Rob's Radiology

Case 8-3-2010 - Turner's

2010-08-07T13:49:00.000-07:00

Good Job Dr. Van Beek - The answer is Turner's

The key finding is a short 4th metacarpal. There is a differential for this finding. Idiopathic is the most common followed by trauma.

If unsure if metacarpal is shortened can use the metacarpal sign - draw a line that abuts the articular surface of the 4th and 5th digits - the continuation of the line should either abut the articular surface (or really small portion of the head) of the 3rd or not touch it at all. If it transects the 3rd - the 4th and/or 5th digit is short

Sicle Cell/Thalassemia - usually diffuse osseous abnormalities but is often asymmetric

Juvenile idiopathic arthritis - often asymmetric but extensive involvement is common; look for overgrown epiphyses.

Turner's (XO) syndrome has a high association with short 4th metacarpal. It can also be seen involving the 3rd and 5th metacarpals but 4th is most common. May see Madelung deformity of the carpus bones and may see metaphyseal excresences. Resnick describes findings of "drumstick" phalanges and thin bones.

Pseudohypoparathyroidism/Pseudo-Pseudohypoparathyroidism - 4th and 5th metacarpal shortening is most common and may see 1st as well; may see soft tissue and basal ganglia dystrophic calcification; End organ resistance to parathyroid hormone - therefore PTH is elevated and may see osteopenia with variable features of hyperparathyroidism

Hypoparathyroidism - 4th and 5th usually most involved but may have diffuse shortening.

VATER - radial sided shortening or absence

If all digits are involved the differential is different - hypothyroidism, mucopolysaccharidoses, achondroplasia, hypochondroplasia, Noonan syndrome, hypoparathryoidism, chondrodysplasia punctata.

As always - Please don't steal images without asking.

References - StatDx.com and http://chorus.rad.mcw.edu/doc/00368.html ; Bone and Joint Imaging by Resnick and Kransdorf

You Are Not Forgotten

2010-03-07T17:16:00.000-08:00

Sorry, I am studying for Boards. By late May/early June - I will be back. Have fun and I promise the site will be even better.

Rob's radiology

NM Cases 1, 2 and 5

2009-09-12T10:15:00.000-07:00

Case 1 - no activity on Pertechnetate scan - most likely subacute thyroiditis

Case 2 - Single nodule with intense uptake and suppression of the rest of thyroid - autonomous nodule

Case 5- Cold Nodule - concern for thyroid carcinoma which is what it turned out to be.

I-123 and Technitium-99m pertechnetate are most commonly used imaging radionuclides
I-131 can also be used for uptake
I-131 - Beta emitter and has 1/2 life of 8 days. principal gamma emission is 364 emitter. I-131 advantage - low price and ready availability. Disadvantage - long 1/2 life and high-beta emission (esp. to thyroid - about 1 rad/microCi); good for tumor follow up due to long half life
I-123 - same behavior as iodine. Nuclide of choice for thyroid imaging. Decays by electron capture - 159 KeV and 1/2 of 13 hours. Low background activity. Disadvantages - high cost (produced by cyclotron), availability and delivery.
Tech 99m - trapped by thyroid but not organified; 6 hour 1/2 life; 140 KeV - ideal for gamma camera; can give higher doses and acquire quickly w/ less risk of motion; higher background than iodine (only 1-5% trapped); Salivary glands - well seen; preferred nuclide when patient has been on thyroid blocking agents or unable to take medication orally or study must be completed in less than 2 hours.
Both Tech and iodine - cross placenta and secreted in breast milk
NRC recommends stopping breast feeding if I-131 exceeds 1 microCi
I-131 - not recommended for children.
Radioiodine Uptake test - Useful for clinical index of thyroid function.
Often for determining how much uptake will be present for therapy.
Useful for differentiating Grave's from subacute thyroiditis or factitious hyperthyroidism
Basic idea - the more active the gland the more iodine will be taken up. Measurements obtained at 4-6 hours and 24 hours post administration.
4-6 - normal is 6-18%; 24 - 10-30%
Patient should be NPO after midnight
I-123 10-20 microCi; I-131 5 microCi
Neck compared with neck phantom. Probe - 25-30 cm from anterior neck
Equation - (neck counts-thigh counts)/counts in standard1
4-6 hour uptake recommended - esp for the possibility of a rapid turnover Grave's
Factors affecting uptake - Too much iodine in diet (low uptake); too little (high uptake)
Increased uptake factors - hyperthyroidism, early hashimoto's, recovery from subacute thyroiditis, Rebound after antithyroid meds; Enzyme defects; Iodine deficiency; Hypoalbuminemia; TSH; tumor secreted stimulators; Pregnancy
Decreased uptake factors - hypothyroidism; iodine overload (contrast); meds; subacute or autoimmune thyroiditis; thyroid hormone tx; ectopic secretion from tumors (struma-ovarii etc); renal failure
Compounds that decrease uptake - adrenocorticosteroids, amiodarone, bromides, butazolidine, Mercurials, methimazole, Propylthiouracil; nitrates; Perchlorate; salicylates; kelp, Cytomel, synthroid, contrast
Renal failure - iodides are retained leading to larger pool of iodine which will compete with I-123 or I-1316.
B-blockers - do not affect function of thyroid and does not affect uptake.
Chronic Thyroiditis - Hashimoto's - most common form of inflammatory disease of thyroid
Likely Autoimmune; usually female
Thyromegaly - presenting w/ possibly mild hyperthyroidism or hypothyroidism
Early - scan shows diffusely uniform like Grave's
Later - coarse patchy activity - similar to multinodular goiter
Acute (bacterial), subacute (viral or autoimmune) - usually diagnosed on clinical or physical grounds - scanning little role
Subacute - painful swollen gland w/ elevated thyroid hormone levels but depressed uptake - little or no localization
Cold Nodule - Most common - colloid cyst (70-75%)
Carcinoma - 15-25% - this is why every cold nodule should get US and possible biopsy.
Miscellaneous - <15%>
Factors increasing risk of malignancy - younger patients, male, hx of rads to head and neck, hard lesion, other masses in neck, no shrinkage on thyroid hormone, family hx.
Factors decreasing risk - older, female, sudden onset, tender or soft lesion, multiple nodules, shrinkage on thyroid hormone.
US - useful for showing solid versus cystic (not benign vs malignant).
Hot nodules almost always represent hyperfunctioning adenomas of which 1/2 are autonomous
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Often not suppressible by thyroid hormone and independent of pituitary axis.
Can suppress surrounding thyroid
Warm - may represent a cold nodule that has overlying normal thyroid tissue - so have to get multiple views.

July 14 Cases 1-3 answers

2009-07-26T19:39:00.000-07:00

Case 1 - 2 different examples of Meningioma.

Case 2 - BB to the eye.

Case 3 - Epidural hematoma.

Sorry my family got back from long trip so not a lot of time for detailed descriptions. Will do more later promise.

As far as Case 2 - the movie was -

Case 1 Answer 7-6-2009 Thyroid (Grave's) Ophthalmopathy

2009-07-12T15:23:00.000-07:00

What we see is enlargement of the extraocular muscles that "spares" the myotendinous junction.

This is Thyroid Ophthalmopathy

Usually occurs in patients with Grave's disease - but can be seen in any thyroid state

Resolves in >90% of patients

Most common cause of proptosis in adults

Histology - inflammatory leukocytic infiltration with edema and deposition of mucopolysaccharides - leading to fibrosis, lipomatosis, fatty degeneration.

Can compress optic nerve leading to optic neuropathy

Can cause diplopia due to muscle entrapment

Proptosis - can lead to corneal ulcers and conjunctival congestion

Most frequently involves medial and inferior recti - IMSLow - Inferior, medial, superior, lateral; muscles >4 mm

More frequent in women but more severe in men

Expansion of orbital fat

Upper and lower eyelid retraction

Often bilateral and symmetric

Painless

TX - prednisone, radiotherapy, surgical decompression, thyroid surgery, I-131

DDX - pseudotumor (painful, unilateral, involves tendons, inflammed fat, good response to steroids) [can be idiopathic, sarcoid, endocrine, focal infections, foreign bodies], cavernous hemangioma of the orbit, Histiocytosis X, cavernous sinus thrombosis, intraconal varices, lacrimal gland tumor and don't forget mets (usually osseous)

Imaging - Ultrasound, CT (good bone imaging and shows all the features but has radiation), MRI

References: http://emedicine.medscape.com/article/383412-overview ; Neuroradiology Companion by Mauricio Castillo and Primer of Diagnostic Imaging by Weissleder et al.

Case 2 Answer 7-6-2009 - Perineural spread.

2009-07-12T14:14:00.000-07:00

The imaging demonstrates a lesion in Meckel's cave that is low on T1, dark on T2 and enhances. There is denervation atrophy of the pterygoid muscles on the right and opacification of the right mastoid air cells.

With imaging like this, you need to think of peritumoral spread along the cranial nerves. This is an odd example in that biopsy revealed Lymphoma.

Perineural spread - tumor or other pathology spreads along tissues of neural sheath
Common in head and neck cancer
In head and neck cancer - major negative prognostic indicator
Most common malignancies - salivary, mucosal and cutaneous
Adenoid cystic frequently spreads by perineural tumor spread
SCC of mucosal and cutaneous can
Desmoplastic melanoma is common
Often present at time of diagnosis; rarely present prior to detection
Can present as recurrence or occur at the same time as recurrence
Common hx - new cranial neuropathy
Any tumor that are adjacent the skull base foramina are at risk of Perineural tumor spread; esp - masticator space, Meckel's cave, cavernous sinus and Pterygopalatine fossa
Perineural spread - can be retrograde (toward CNS) or antegrade (away from CNS)
Benign - some benign disorders spread along cranial nerves (essentially like PNS or similar to it by imaging) - schwannoma/neurofibroma, meningioma, rhinocerebral mucormycosis, sarcoidosis etc.
Signs and Symptoms - pain and paresthesias
V3 - weakness and denervation of muscles of mastication
Facial - variable weakness or paralysis
Most commonly affected - trigeminal and facial
V2 (maxillary) and V3 (mandibular) - most common branches of CN V involved
V1 - sensory to eye, lacrimal gland, conjunctiva, some nasal mucosa and upper face
V1 - often from cutaneous lesion in supraorbital region; rare for intraorbital process to spread to V1
V2 - sensory to mid and upper lateral face, mucosa of palate, sinonasal region, maxillary gingiva and maxillary teeth
V2 - to spread along V2 from nasopharynx - must access pterygopalatine fossa (PPF) - often by nasal cavity then sphenopalatine foramen
V2 - from skin along maxillary distribution - infraorbital nerve or zygomatic nerve
Pterygopalatine fossa - Pterygopalatine ganglion, internal maxillary artery; bounded posteriorly by pterygoid plates, medially by palatine bone, anteriorly by maxillary sinus
PPF - communicates laterally with infratemporal fossa with pterygomaxillary fissure
PPF - communicates w/ intracranial space by foramen rotundum
PPF - communicates with nasal cavity (medially) via sphenopalatine foramen
PPF - Vidian nerve provides preganglinonic parasympathetic component of pterygopalatine ganglion
PPF - communicates with greater and lesser palatine foramina inferiorly through the palate
V3 - sensory innervation to skin of lower face and pre-auricular/temporal region, mandibular teeth, mucosa of mandibular gingiva, floor of mouth, ant 2/3 of tongue, buccal mucosa
V3 - motor to musscles of mastication, mylohyoid and anterior digastric
V3 - PNS - travel through foramen Ovale to Meckel's cave
Facial Nerve (CN VII) - typically only 2 branches are affected - descending facial nerve (from parotid malignancies or lesions that involve the parotid) and the GSPN (greater superficial petrosal nerve)
Descending facial nerve - can travel to geniculate ganglionand even through labyrinthine segment to involve internal auditory canal
GSPN - small branch that leaves geniculate ganglion and exits superior surface of temporal bonte through facial hiatus to become intracranial; courses anteromedially beneath Meckel's cave to foramen Lacerum to join deep petrosal nerve (carotid sympathetic plexus) and become the Vidian nerve through Vidian canal
Imaging - minimum need axial T1, axial T2, and 3 plane postcon T1 (with at least one in fat-suppressed form)
T1 - look for loss of normal fat
Look for widening of foramina - foramen ovale, mandibular foramen, foramen rotundum, PPF, foramen and canal for infraorbital nerve, vidian canal, palatine foramen, stylomastoid foramen, descending facial canal
Look for enhancement
Look for involvement of Meckel's cave
Indirect findings - denervation of masticator muscles, anterior digastric, mylohyoid
Early denervation - T2 bright and enhancement with post con
Late - atrophy and fatty infiltration

Reference - MR Imaging of Perineural Tumor Spread by Lawrence E. Ginsberg; Neuroimaging Clinics of North America 14 (2004) 663-667

6-27-2009 Case 2 answer - Capillary Telangiectasia

2009-07-06T18:18:00.000-07:00

Lesion that is not seen on T1 precon but demonstrates "stipple" enhancement on postcontrast images in the pons - this is consistent with capillary telangiectasia.

Most are in pons - but can be seen in cerebral, cerebellar and spinal cord tissue
Nearly always asymptomatic and no further intervention necessary
16-20% of intracerebral vascular malformations at autopsy
CT - almost always normal
T1 - hypo to iso to brain
T2 - normal (often) or slightly hyperintense
T2* - can be normal or low in signal - but not due to hemorrhage or calcification - and likely represents deoxyhemoglobin in slow flowing blood
T1 postcon - brush like or stippled pattern
No mass effect
2/3 have enlarged vessel that may represent a draining vein.
Often considered an acquired lesion and may represent obstructed venous drainage
Can be seen in association with cavernomas and AVMs
Does not show up on angiography

Reference - http://www.ajnr.org/cgi/content/full/22/8/1553 and http://emedicine.medscape.com/article/337451-overview

6-27-2009 Case 1 Answer - Choroid Plexus Carcinoma

2009-07-06T17:19:00.000-07:00

CT - demonstrates a hyperdense structure in the lateral ventricle causing hydrocephalus in a young patient. Pathology revealed a choroid plexus carcinoma.

Neoplasms of ventricular system are usually easy to recognize but pathology is sometimes difficult to determine by imaging characteristics
Choroid plexus - found in the ventricles - highly vascular and produces CSF
Choroid plexus neoplasms - usually highly vascular and produce hydrocephalus
Benign - papilloma; Malignant - carcinoma
Most frequently found in atria and posterior portion of lateral ventricles
Other highly vascular tumors are commonly seen in this site - mets and meningioma
Ependymal cells - ependymoma
Subependymal glial cells - subependymomas and subependymal giant cell astrocytoma
Septum pellucidum - central neurocytoma
Choroid plexus - found most commonly in atria, third ventricle and 4th ventricle (not seen in temporal horns or aqueduct of Sylvius)
50% of tumors are in lateral ventricles, 40% in 4th and 5% in 3rd.
Rare - extraventricular areas like CPA, suprasellar cistern etc
Choroid plexus tumors aren't that common overall but 10-20% of brain tumors in those less than 1 yr.
80% are benign papilloma and rest are carcinoma
Those in lateral ventricle are most likely to present <10
Most present due to symptoms of hydrocephalus
Other symptoms - cranial nerve palsies, seizures, coma, and one report of psychosis
Choroid plexus tumors - have an association with Li-Fraumeni and Aicardi syndromes
Choroid plexus papilloma - 5 yr survival - practically 100%
Choroid plexus carcinoma - 5 yr survival - 26-50%
Choroid plexus tumors - cauliflower like well circumscribed masses with lobulations
hemorrhage and cyst formation can be seen
Signs of carcinoma - necrosis and parenchymal invasion
Lateral ventricle choroid plexus - attached at trigone
3rd ventricle - attached at roof
4th ventricle - attached at posterior medullary velum
Can have ball-valve effect for hydrocephalus
Atypical choroid plexus papilloma - one or 2 histologic malignant features but not enough for carcinoma
Papilloma and Carcinoma (but much more frequent for carcinoma) can have seeding of CSF
CT - most tumors are iso or hyperattenuating
CT - with enhancement - avid enhancement
CT - 24% see calcifications
T1 MR - iso or hypo to brain
T2 - variable and often see flow voids within the lesion
T1 postcon - avid enhancement
Carcinoma - may have more variable CT and MR appearance; may have less hydrocephalus; look for parenchymal invasion and vasogenic edema
Carcinoma - Increased uptake on FDG PET
Imaging - papilloma and carcinoma has a lot of overlap therefore unless obvious malignant features are present cannot exclude carcinoma when imaging looks like a papilloma
Lateral ventricular lesions - supplied by anterior choroidal, medial posterior choroidal and lateral posterior choroidal arteries
4th ventricular - choroidal branches of PICA
Lesions in trigone - less than 10 - think papilloma/carcinoma; 10-40 - think low grade glial like ependymoma or subependymoma; >/= 40 - think meningioma, mets, lymphoma
Intraventricular meningioma - rare and almost always older (caveat - 1/5 of all meningiomas in children are intraventrciular)

References - http://radiographics.rsnajnls.org/cgi/content/full/22/6/1473 and http://www.ajnr.org/cgi/content/full/20/5/882

6-23-2009 Case 1 - DNET

2009-06-27T08:18:00.000-07:00

Alright - the images from top to bottom - CT, FLAIR, GRE/T2*, ADC, DWI, postcon T1, precon T1 and T2

This case represents a Dysembryoplastic Neuroepithelial Tumor (DNET).

1. Benign tumor of neuroepithelial tissue arising from cortical or deep grey matter.

2. Virtually always in patients with refractory partial seizures

3. Majority - younger (in 20's or younger) and male

4. Neurologic deficits are not common

5. temporal (often amygdala/hippocampus) > frontal > parietal; can also be seen in caudate, pons, and cerebellum

6. Cerebellar - present with vertigo, ataxia and gait disturbances

7. Tend to be stable, recurrence is rare but malignant degeneration has occured - therefore long term follow up is recommended.

9. Imaging - similar to low-grade gliomas - can be difficult do differentiate from diffuse astrocytoma, ganglioglioma and oligodendroglioma

10. CT - hypoattenuating mass with occasional calcifications, may see remodeling of inner table; minimal or no mass effect; may resemble a stroke but no evolution over time

11. MR - low signal on T1, high on T2 without surrounding edema; 1/3 enhance and usually peripheral or nodular (i.e. 2/3 don't); if enhancing - may be something more ominous

12. Some have a "soap bubble" appearance; some appear like an enlarged gyrus; can have multicystic appearance

13. Often when cortical - wedge shaped with point toward ventricle

14. FLAIR - mixed hypo/iso with bright rim; GRE - occasionally bleed and can be confused with cavernoma (rare); PD - hyperintense rim; No restricted diffusion

15. HMPAO - hypoperfusion (ictal may have uptake); No uptake on Thallium-201; PET - hypometabolism

16. DDX - Taylor Dysplasia (single Tubersous sclerosis lesion - expand gyrus, nonenhancing, looks like a tuber), Neuorepithelial cyst (nonenhancing single or complex cyst, no bright rim), ganglioglioma (strong enhancement, calcs, cyst), PXA (enhancing nodule adjacent to pia and look for dural tail)

References - http://radiographics.rsnajnls.org/cgi/content/full/21/6/1533 ; statdx.com

Case 2 - Developmental Venous Anomaly

2009-06-27T07:43:00.000-07:00

This is a postcon T1 image. It has a "medusa head" appearance of enhancing branching pattern in left frontal lobe. This represents dilated veins in a Developmental Venous Anomaly (DVA). You do not biopsy it.

1. DVA - aka venous vascular malformation or venous angioma
2. Congenital venous anatomical variant in venous drainage of brain.
3. 2% of population and is the most common venous malformation
4. Incidental and don't cause symptoms
5. If symptoms - likely due to a cavernoma which are sometimes seen in conjunction with DVA
6. No surgery as can cause venous infarct
7. 15-30% are associated with another vascular malformation (cavernoma, AVM, capillary telangiectasia) - the most common is a cavernoma
8. Complications - hemorrhage (likely from associated cavernoma), thrombosis of venous malfomation (which leads to venous infarct and can lead to hemorrhage), seizures (mentioned in literature but not much literature to support claim)
9. DVA - fine network of enlarged medullary venules that join to form central venous flow tract that drains to superficial or deep venous system
10. Thought to occur as alternative when normal drainage is not present.
11. CT - not seen on noncon; contrasted CT - large vascular structure in brain parenchyma w/ smaller radiating veins and the large vascular structure draining to superficial or deep venous system
12. MRI - best seen on postcon images - spoke wheel or caput medusa of venules to larger vein that will drain to deep or superficial venous system; intervening brain parenchyma is normal; draining vein usually has straight course
13. If draining vein is near lateral ventricle - usually drains to subependymal vein which is often enlarged
14. Look for other vascular malformations - MRI preferred method

Reference - emedicine.com

Femoral Artery Pseudoaneurysm - Answer Case 1 6/14/2009

2009-06-21T11:44:00.001-07:00

This series of images from an abd/pelvis CT demonstrates a hyperdense focus of contrast adjacent to the left common femoral artery with a small neck communicating the two. The patient had a recent cardiac catheterization. This represents a Left common femoral artery pseudoaneurysm.

1. < 5% of arterial access

2. Risks - large catheter, anticoagulation, calcified arteries, HTN, too low a puncture, obesity

3. Physical Exam - pulsatile hematoma at puncture site with a bruit.

4. Ultrasound - rapid diagnosis

5. Small - spontaneously resolve

6. Complication - infection and rupture

7. Tx - surgery, ultrasound guided compression and ultrasound guided thrombin injection

8. US-compression - neck - compress 20-30 min - complications are embolization and thrombosis

9. US-thrombin - thrombin 1000 Units/mL - use 1mL syringe - slow injection into pseudoaneurysm away from the neck; occasionally require more than 1 injection; complication - distal thrombosis from thrombin in system.

Reference - VIR requisites (Kaufman et al)

Pneumotosis - Answer Case 2 6/14/2009

2009-06-21T11:41:00.001-07:00

In this image, there is air outlining the wall of large bowel. This reflects pneumotosis intestinalis. The differential for this process is long.

DDx
1. Mesenteric ischemia/infarction.
2. Necrotizing enterocolitis
3. Post anastomosis
4. Intestinal obstruction/volvulus
5. Gastric, duodenal ulcers
6. Perforation of diverticulum
7. Pseudomembranous colitis
8. Post endoscopy and post trauma
9. COPD
10. Steroids
11. Collagen vascular disease
12. Mesenteric abscess
13. Neoplastic bowel wall damage

Therefore, the key is to know the patient's history and clinical scenario. This turned out to be a benign pneumotosis.

reference - http://www.ajronline.org/cgi/content/full/177/6/1319; uhrad; http://radiographics.rsnajnls.org/cgi/content/full/22/5/1093

Colon cancer - Answer Case 3 6/14/2009

2009-06-21T11:37:00.000-07:00

The first image from a single contrast water soluble enema demonstrates abrupt cutoff in the descending colon. CT images of the abdomen and pelvis demonstrates descending bowel wall thickening and adjacent lymph nodes consistent with cancer of the colon. Additionally, there is a hypodense lesion in the liver that is irregular and most likely represents a metastasis to the liver.

TAR syndrome Case 3 6/7/2009

2009-06-13T15:11:00.001-07:00

So what we see is bilateral absent radii. Absence of the radius is associated with multiple disorders and syndromes. Therefore because both radii are missing suggests a syndrome and the history of thrombocytopenia helps come up with a diagnosis.

TAR syndrome - thrombocytopenia absent radius syndrome.

Differential - Fanconi's Anemia, VACTERL syndrome (Vertebral anomalies, anal atresia, cardiac anamolies, tracheo-esophageal fistula, radial ray anomalies) etc.

Fanconi's - oftentimes has missing thumbs. Short stature, skeletal dysplasias, bone marrow failure, cellular sensitivity and risk for solid tumors and leukemias; needs bone marrow transplant; generally considered to be Auto recessive.

VACTERL - obviously has a lot of other additional problems.

References - http://www.wikipedia.org/ and http://www.medcyclopaedia.com/

Melorheostosis - Case 2 6/7/2009.

2009-06-13T14:17:00.000-07:00

What we see is hyperostosis of the cortical bone of the left humerus. It is benign in appearance. No soft tissue mass, no abnormal periosteal reaction or destructive changes. This is most consistent with melorheostosis.

Classically described as flowing hyperostosis
Dripping candle wax sign
Monostotic (single bone), monomelic (single limb), or polyostotic (multiple bones) - but often on a single side of body even when polyostotic
Often follows a sclerotome
Irregular thickening of cortical bone (cortical hyperostosis)
Rare sclerosing bone dysplasia
Patient's often discovered incidentally when looking for something else
When symptomatic - often doesn't present till late teens early adulthood - limb stiffness and pain
Can progress to disability even amputation.
Can cause muscle contractures, tendon and ligament shortening and soft tissue involvement; growth disturbances (increased width, angulation, unequal limb length)
Soft tissue - tense, erythematous and shiny skin; anomalous pigmentation; induration and edema of subq tissues; fibrosis; weakness and atrophy of muscles; and linear scleroderma
Predominately limbs with lower more common than upper extremity
Also can be seen in skull, facial bones, ribs and vertebrae
If clavicle, scapula, or pelvis - adjacent limb usually also involved
Can have endosteal hyperostosis as well
Can appear like osteopoikilosis - esp in tarsal and carpal areas
Pelvis and scapula (flat bones) - may appear radiating or localized sclerotic patches
25% have soft tissue calc and/or ossification
Can be associated with linear scleroderma, osteopoikilosis, osteopathia striata, Neurofibromatosis, tuberous sclerosis, hemangiomas
Have also been associated with glomus tumors and AVMs
5 basic imaging patterns - classic, osteoma-like, myositis-ossificans like, osteopathia striata like, mixed

References - http://radiology.rsnajnls.org/cgi/content/full/246/2/638 ; Bone and Joint Imaging (Resnick - i.e. Baby Resnick)

Situs Inversus - Case 1 6/7/2009

2009-06-13T13:34:00.000-07:00

Great job - Elisha - you got it within 5 minutes of posting.

So the first image shows dextrocardia. In the original set, the second image shows the stomach bubble on the scout film on the right. In the second image shown here, the stomach is clearly on the right and the ileocecal valve is noted on the left (best seen at the left iliac crest).

This patient has situs inversus.

Situs - describes position of cardiac atria and viscera
Situs solitus - normal position
Situs inversus - mirror image of situs solitus
Cardiac situs - dictated by atria. (but not the apex - i.e. you can have reversal of left and right atria but apex still points to left)
Can have situs inversus with cardiac in normal axis (levocardia) or dextrocardia.
When there is situs inversus - the lungs are often inverted as well - the left has 3 lobes and the right has 2 lobes.
Dextrocardia may be present but viscera is in the correct position.
When mirror image is exact - called situs inversus totalis.
When can't tell - situs ambiguous - heterotaxy - liver may be midline, spleen absent or multiple, atrial morphology unclear, and possibly malrotated bowel.
2 primary types of situs ambiguous - asplenia syndrome (right isomerism) and polysplenia syndrome (left isomerism)
Classic asplenia - double right sidedness - bilateral right atria, absent speen, both lungs have 3 lobes, central liver, aorta and IVC on same side of spine
Classic polyspenia - double left sidedness - multiple spleens, bilateral left atria, IVC dicontinuity with azygos or hemiazygos continuation, both lobes of lungs have 2 lobes
All the different varieties are rare - with situs inversus - 0.01%
Situs inversus totalis - associated with Kartagener syndrome (primary ciliary dyskinesia) (my patient didn't have it).
Kartagener's - repeated sinus and pulmonary infections - with pulmonary sometimes leading to bronchiectasis (esp lower lobes); 20% of patients with situs inversus; transmitted by Auto Recessive; only 50% of those with Kartagener's have situs inversus; also reduced fertility or infertility is common
Situs inversus - normal life expectancy (except for those with severe pulmonary complications and those with cardiac anomalies)
False positive and negative results are usually due to human error with labeling - that is why quality assurance is so important.

Reference - http://www.emedicine.com/ - Dr. Annamaria Wilhelm from Mayo Clinic

5/17/2009 case 3 answer

2009-05-23T21:32:00.000-07:00

The finding is dislocation of the left shoulder with fracture of the greater tuberosity. This is an excellent example of how you need to look at all corners of the film. If this patient had multiple injuries, the dislocation could be missed with possible complications later.

5/17/2009 case 2

2009-05-23T21:02:00.000-07:00

The image above is the follow up examination. The original image demonstrated a pathologic fracture within a lytic lesion. If you look closely, there is a splinter of cortical bone at the bottom of this image which was obtained with the patient upright and represents the "fallen fragment" sign. This sign is consistent with a cystic structure i.e. a simple bone cyst. This is the most common location for a simple bone cyst and 20% of SBC's have the "fallen fragment" sign.

SBC

originally defined in 1910
fluid filled cyst commonly in the metaphysis of long bones
benign
idiopathic - possibly venous obstruction and blockage of interstitial fluid drainage in an area of rapidly growing/remodeling cancellous bone
cyst contains serous fluid and maybe blood products
May have septa especially after fracture.
wall - mesothelial cells and sometimes multinucleated giant cells
M:F; 2:1; usually in the first or second decade of life
usually single - if multiple tend to be older and male
Humers and femur are most common (esp proximally) ; less common - tib, fib, radius, ulna
older patients (esp >20) - calcaneus and iliac bone and other flat bones
Asymmetric unless fx
X-ray - well defined (geographic), lytic lesion with narrow zone of transition, intramedullary and usually abut the physis. thin sclerotic wall
May cause thinning and expansion of the bone and can be multiloculated.
Fallen fragment sign - pathognomonic
Tx - curretage, bone grafting, steroid injections, cryotherapy, nailing

reference: emedicine.com and http://radiology.rsnajnls.org/cgi/reprint/209/3/884-b?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=fallen+fragment+sign&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

5/17/2009 case 1

2009-05-23T20:32:00.000-07:00

On the first image - there is loss of the Arcs of Gilula and a pie shaped lunate bone. On the lateral view, there is loss of normal alignment between radius and lunate and the lunate with the capitate. This is called the "spilled teacup" sign. Additionally, there is a dorsal (posterior) chip of bone which signifies a fracture of the triquetral bone of the wrist. This is called a transtriquetral lunate fracture-dislocation.

Lunate dislocations - are the most severe and most unstable of the carpal dislocations. There are multiple tears of the carpal ligaments such as the scapholunate ligament, lunocapitate, lunotriquetral and radiolunate ligaments. The most common dislocation is the perilunate dislocation which is where the alignment between the lunate and capitate is disrupted but the radius-lunate alignment is maintained.

reference: http://www.ajronline.org/cgi/reprint/133/3/503.pdf and http://radiographics.rsnajnls.org/cgi/content/full/28/6/1771?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=lunate+dislocation&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT

5/9/2009 Case 5 Answer

2009-05-15T18:30:00.001-07:00

This poor unfortunate patient was having complications with the patient's hemodialysis catheter. Evaluation demonstrates large clot burden in the IVC above the renal vein origins. This patient is at risk for pulmonary embolus.

Treatment options include - IVC filter placement, oral anticoagulation and thrombolysis. Because the patient has multiple venous occlusions in the neck and upper extremity veins, IVC filter cannot be placed.

References: VIR Requisites (Kaufman et al)

5/9/2009 Case 4 - Answer

2009-05-15T18:18:00.000-07:00

What we see is active extravasation from the distal common iliac artery on the right just above the bifurcation.

Treatment - could include surgery or endovascular stent-graft placement

Interventional techniques are not ideal in Ehlers-Danlos patients as they have a lot of complications but in this emergent case it is acceptable. Endovascular stent-graft was applied.

Reference - VIR Requisites (Kaufman et al)

5/9/2009 Case 3 - Answer

2009-05-15T18:03:00.000-07:00

The first image demonstrates a narrowing in the cephalic vein. The second image shows angioplasty of the vein. The third image (which is the image from the Rob's Radiology fan page) demonstrates extravasation after angioplasty.

The procedure is a fistulogram with resultant complication from angioplasty.

Surprisingly, treatment often is easily treated with inflating the balloon until the bleeding stops. The vein often seals after the inflation and no further problems are usually seen. Other treatments include compression or stent-grafts. But stent-grafts are not ideal for crossing joints as in this case which is at the elbow.

Other acute complications - thrombosis and dissection. Thrombosis can be treated by drug or mechanical. Dissection can also be treated with balloon.

References - VIR Requisites (Kaufman et al) and Handbook for Interventional Radiologic Procedures (Kandarpa and Aruny)

5/9/2009 Case 2 - answer

2009-05-15T15:55:00.000-07:00

The CT - demonstrates contrast adjacent to the iliac limb in the aneurysm sac (it changed on the delayed scan so is not a calcification).

The angiogram - demonstrates the endograft in the aorta and selective catheterization of the artery that supplies a lumbar artery that is causing an endoleak to the sac around the graft.

The answer is type II endoleak in association with an abdominal aortic endograft repair of an abdominal aortic aneurysm.

Endoleaks are leakage of blood into the excluded aneurysm sac after endograft treatment for an aneurysm (usually AAA)
Endoleaks are classified and the type has prognostic factors and can indicate the severity of need for treatment.
Type I - defect in apposition of an end of the stent-graft (proximal or distal) that leads to leakage into the sac.
- can be seen immediately after deployment due to steep angulation, incomplete expansion, or tortuosity.
- can be seen late due to changes from shrinking of the sac
- high pressure situation and needs to be treated urgently.
- contrast seen centrally with extension to the affected edge of the graft; us - may show pulsation at the edge.
Type II - most common - a branch is supplying retrograde flow into the aneurysmal sac
- low pressure situation and may not need repair if the sac is decreasing in size
- imaging - peripheral contrast within sac
- if increasing in size - should treat with embolizing of branch
- often in abdominal aorta - lumbar or IMA is source.
- many close spontaneously
Type III - break in body of stent graft or defect in components
- high pressure situation requiring urgent care
- a jet may be visible - contrast seen around graft
- often large amount of contrast seen.
Type IV - opacification of sac seen at time of procedure and no obvious source identified and stop on their own
Type V - "endotension" - increasing size of sac (over studies) without sign of source - not emergent but needs treatment.

reference: http://www.ajronline.org/cgi/content/full/192/4/W178

5/9/2009 Case 1 - answer

2009-05-15T15:17:00.000-07:00

The plain film demonstrates massive dilatation of the sigmoid colon. The CT demonstrates massive dilatation of the descending and particularly the sigmoid with a transition in the distal sigmoid. No focal lesion or obstructing process identified.

These findings are consistent with Ogilvie's syndrome or Pseudoobstruction of the colon.

Can be acute or chronic
Acute needs rapid decompression especially when there is dilatation of the cecum (to prevent rupture).
Not paralytic ileus as it has a transition but not obstructive as no stricture will be found and the air should change with position.
Treatment - can be conservative - NG, enemas, neostigmine - or aggressive with colonoscopic decompression or even percutaneous cecostomy.
Loss of parasympathetic ganglions may be a factor
Transition is often seen at splenic flexure (not our case) which may be related to change in parasympathetic control from vagus to sacral nerves at this level.
Acute - often related to recent surgery (of any sort) or major illness.
Chronic - recurrent and rarely perforates.

References: http://www.ajronline.org/cgi/content/full/190/6/1521 ; http://radiographics.rsnajnls.org/cgi/reprint/6/6/995.pdf

5/3/09 case 3 answer

2009-05-08T20:26:00.001-07:00

Fan's of Rob's Radiology - the image shows a port overlying the chest wall on the right and the detached catheter portion embolized into the pulmonary arterial system.

Diagnosis - detached catheter embolized into the PA system.

Next step - Consult IR who can retrieve the tubing with snares under fluoroscopy.

This is an uncommon complication.

5/3/2009 Case 2 Answer

2009-05-08T20:14:00.001-07:00

Fan's of Rob's Radiology

The original image shows an esophogram that has contrast in the airway. Going back and looking at the oral transfer - the patient is aspirating.

Therefore - the primary team needs to be notified about the severity and fact that the patient is aspirating spontaneously. Other information that is helpful is whether the patient responds and knows that he/she is aspirating. This patient cannot be trusted to eat or drink. This patient is at high risk for pneumonia and other problems.

You do not want to use water soluble contrast agents (like gastrograffin) as this can cause a life-threatening mediastinitis when aspirated. Therefore, barium is the contrast of choice.

5/3/2009 Case 1 Answer

2009-05-08T19:33:00.000-07:00

Fans of Rob's Radiology - this is a Colloid Cyst.

Benign lesion in the anterior 3rd ventricle (near foramen of Monro)
Neuroepithelial in origin - is the leading theory
Can cause sudden death by obstructing the foramen of Monro
May have pendulous attachment to 3rd ventricular roof
Usually found in adults but has been reported in children
Often found incidentally
Headaches - brief and intermittent
Headaches - in some patients are positional
Hydrocephalus, drop attacks, momentary loss of consciousness, progressive dementia, papilledema, diplopia,
CT - typically dense and near the foramen of Monro
MRI - variable appearance depending on the contents - most common Bright on T1 and dark on T2
Can be followed but commonly surgically resected to prevent the risk of sudden death.

references - http://www.ajnr.org/cgi/content/full/21/8/1470 and emedicine.com

The best case of whatever it is - Answer

2009-05-08T18:56:00.000-07:00

The answer is - Acute epiploic appendagitis

This is inflammation of the epiploic appendages (fat outpouching on the serosal surface of the colon). This is likely secondary to torsion or venous obstruction in this fat outpouching.

It has a nonspecific presentation. Commonly has focal tenderness (usually lower abdomen/pelvis). The most common presentation is focal left lower quadrant pain. It is most commonly in the sigmoid followed by descending, cecum and then the ascending. Commonly misdiagnosed as diverticulitis or appendicitis. Often in 4th-5th decade and usually male. Risk factors - obesity, hernia and "unaccostomed exercise".

Typical imaging appearance - CT - fatty process adjacent to the colon (commonly 1-3 cm but can be as big as 5 cm) with enhancing rim and adjacent inflammatory changes. It often has a dense center that represents the occluded central vein (about 54% of the time) - aka central dot sign.

US - oval noncompressible hyperechoic focus adjacent to colon at site of maximum tenderness with no central flow on color doppler.

MRI - T1 and T2 show lesion that looks like fat that has a peripherally enhancing rim on postcon T1 fat sat.

Evolution - images obtained at 6 months or greater show total resolution.

Treatment - conservative with pain medications.

Complications - RARE - adhesions, bowel obstruction, intussusception, intraperitoneal loose body (does that mean the appendage falls off and calcifies as loose body in the abdomen? - not clear from reference) and abscess formation.

DDX - Omental infarcts, sclerosing mesenteritis, acute diverticulitis, fatty masses in peritoneum

references - http://www.ajronline.org/cgi/content/full/183/5/1303 ; http://radiographics.rsnajnls.org/cgi/content/full/25/6/1521 - Notice that the primary author is same guy

Eye Test - the Answer

2009-05-02T07:36:00.000-07:00

So the plain films (see photo album on Rob's Radiology fan page on Facebook) demonstrate subcutaneous emphysema and air streaks outlining the mediastinum and proximal vessels. This is consistent with:

Pneumomediastinum.

Pneumomediastinum - air in the mediastinum
Sources
- rupture of alveoli - most common cause - increased pressure (ventilator, mucous plug, foreign body, strain against closed glottis) or damage of cells (pneumonia, emphysema, ARDS)
- laceration of tracheobronchial tract
- GI tract (esp esophagus)
- passage of air from head and neck (sinus fx, dental extraction, vascular channels etc), retroperitoneum, chest wall
The mediastinum communicates with the submandibular space, retropharyngeal space and vascular sheaths in the neck
The retroperitoneum communicates with the mediastinum through the sternocostal insertion of the diaphragm which also communicates with flanks and pelvis
Retroperitoneum also communicates through the periaortic and periesophageal spaces
Clinically - often asymptomatic. Can cause dyspnea and chest pain
Complications - can cause pneumothorax; rarely - cause hypotension due to decreased venous return to the heart from high pressure in pneumomediastinum
Features
Radiograph - look for lucent streaks and bubbles - especially a pleural line above the left heart lateral to PA and aortic arch on frontal view
Lateral View - Air may outline ascending aorta, PA, trachea and bronchi; can outline thymus, sternal insertion of diaphragm and brachiocephalic veins.
Lateral - can see air outline anterior to the heart - in a "pneumoprecardium"
Continuous diaphragm - air between diaphragm and pericardium
Naclerio's V sign - air along descending aorta inserts into an insertion along left hemidiaphragm and forms a V shape (frontal view)
Ring around the artery sign - air around right pulmonary artery (best seen on lateral)
infants - thymic spinnaker sign
Can also get apical cap of lucency - can look like pneumothorax but won't move with position
Pneumomediastinum usually doesn't completely surround the heart and usually has multiple thin streaks

Vs. Pneumopericardium

Usually from penetrating trauma or recent heart surgery
If from ventilator will have pneumomediastinum usually as well - but requires much higher pressures than pneumomediastinum
Not as common as Pneumomediastinum
Often a complete band seen around left ventricle and right atrium
Does not usually extend into the neck or upper mediastinum
Halo sign - band around the entire heart
May outline ascending aorta and main PA but does not extend to arch or trachea
Pneumopericardium - can change with position but pneumomediastinum won't

References - http://www.ajronline.org/cgi/reprint/166/5/1041 ; http://radiographics.rsnajnls.org/cgi/content/full/20/4/1043 ; and Primer of Diagnostic Imaging by Weissleder et al.

What's happening here? - Answer

2009-05-02T05:57:00.001-07:00

So what we see here is air in the stomach and proximal duodenum but not in the rest of the digestive tract. This is the so-called "Double Bubble" sign.

The double bubble is indicative of obstruction of the duodenum. This can be from intrinsic or extrinsic etiologies. Far and away the most common consideration is duodenal atresia. The differential should include duodenal web and stenosis, annular pancreas, Ladd's bands, malrotation, preduodenal portal vein and duodenal or retroperitoneal tumor.

Considerations for next step - Depends on clinical appearance. Surgery consult, possible upper GI. If the patient has any signs of peritoneal symptoms - Ladd's bands and malrotation with volvulus must be considered and may urgently/emergently go to surgery. If the patient is doing well and surgery may be delayed then may want to do Upper GI to exclude malrotation.

This example - Annular Pancreas. The annular pancreas can present in a variable pattern. The pancreas may actually encircle the duodenum or the ventral pancreas could be incorporated into the wall of the duodenum. According to radiographics, only 10% actually obstruct the duodenum. According to emedicine, it always causes at least some stenosis if not outright atresia like in this case. It is a congenital variant. It can be isolated or associated with other congenital anomalies. In neonates when symptomatic - presents like above with obstructive symptoms such as biliary vomiting or as pancreatitis. In adults - if symptomatic at all - may present with "peptic ulcer" symptoms, pancreatitis, or duodenal obstruction.

Duodenal Atresia

Extreme end of the spectrum (diaphragm or web, stenosis then atresia)
Failure of recanalization (favored theory) vs. ischemia
Death without surgery - due to electrolyte loss and fluid imbalance
Associated with Trisomy 21 (Down's) - approximately 20-30%
Anomalies (such as Down's and others) are found in 50% of patients - heart disease, VACTERL, renal anomalies, TE fistula
If has esophageal atresia as well - stomach will be fluid filled midabdominal mass as it is obstructed on both ends
Prenatally - polyhydramnios and double bubble on ultrasound.
Clinically - often have bile stained vomiting
Stenosis and web - are not complete obstructions so often will have some air beyond the narrowing in the 2nd portion of the duodenum.
Patients should do well after corrective surgery.

references: http://radiology.rsnajnls.org/cgi/content/full/220/2/463 , http://radiographics.rsnajnls.org/cgi/content/full/26/3/715 , emedicine.com and Primer of Diagnostic Imaging by Weissleder et al.

What is your Diagnosis? - Answer

2009-05-02T05:05:00.000-07:00

The finding - tracheal deviation to the left.
The differential - superior mediastinal masses - Thyroid goiter, thyroid malignancy, adenopathy, lymphatic malformation (and cysts), aneurysm, vascular masses (malformations, hemangiomas), Ascending through thoracic inlet - Small Cell, parathyroid mass (uncommon), not commonly listed but I have seen - esophageal cancer.

The most likely diagnosis - far and away the most common is thyroid goiter. This case turned out to be thyroid cancer.

Workup - The first and easiest is history and physical exam. Next may consider ultrasound. Ultrasound can demonstrate the thyroid and find areas of concern and be used for biopsy. If the history and physical exam is inconsistent with thyroid - may consider CT.

The patient had ultrasound which revealed a worrisome lesion. The lesion was biopsied showing thyroid cancer. The patient had surgery and the second image is from an I-123 scan which is used to find areas of residual thyroid and possible metastases. There is normal uptake in the salivary glands and GI tract and 2 foci of uptake in the thyroid bed and a lymph node. The patient is then treated with I-131 which is radioactive Iodine that is taken up by thyroid tissue and then the Iodine radiates it. Patients do remarkably well after the therapy but will have to be on lifetime of thyroid hormone replacement.

references - Primer of Diagnostic Imaging by Weissleder et al.

What's This Complication of Crohn's Colitis? - Answer

2009-04-29T17:14:00.000-07:00

So Fans of Rob's Radiology - The answer is a fistula from the colon with the subcutaneous tissue and soft tissue abscess.

Crohn's - named after Dr. Crohn
Transmural process (mucosa, submucosa, muscularis propria and adventitia) vs Ulcerative Colitis which is primarily mucosal
One of the diseases included in Inflammatory Bowel Disease (IBD)
Can involve anywhere from mouth to anus (but usually is either small bowel only, small bowel and colon [45%], or colon only)
2 peaks of presentation 15-35 then 50-80
Risk factors - urban dwellers, whites, Jewish, family history, smoking, OCP, maybe diet
Presentation - fever, abdominal pain, diarrhea, weight loss, obstruction, rarely blood in stool (usually means colonic involvement)
Alternating attacks and remissions
Initially a mucosal process that leads to transmural inflammatory changes with caseating granulomas
Transmural inflammation leads to strictures, obstruction, fistulas, perforation, malabsorption, abscesses
Increased risk of adenocarcinoma of colon and small bowel and lymphoma
Skip lesions - noncontiguous involvement (unlike UC which starts at rectum and travels proximally)
Early imaging - asymmetric, skip lesions, cobblestonse, aphthous ulcers (partial), linear ulcers, fissuring, mural thickening, inflammatory pseudopolyps
Early CT - mural thickening, mural enhancement, target or double halo sign
Subacute to Chronic CT - mural thickening (homogenous and nonenhancing = fibrosis or stricture vs. enhancing wall = reversible inflammatory disease); fibrofatty proliferation (creeping fat), LAD, hypervascularity, inflammatory stranding, phlegmon/abscess
Comb sign - prominent dilated vasa recta
Complications - sinus tracts, fistula, abscess, carcinoma
Extraintestinal -
Hepatobiliary - steatosis (20-50%), Primary sclerosing cholangitis (1-4%), hepatic abscess
Pancreatic - pancreatitis
Musculoskeletal - arthritis; sacroileitis-spondylitis
GU - nephrolithiasis (2-10%)
Eyes - uveitis
Skin - erythema nodosum and erythema gangrenosum
Lab - positive ASCA (Anti-S Cerevisiae Antibodies) and negative p-ANCA is suggestive of Crohn's while vice versa is suggestive of UC.
Treatment - ASA, steroids, immunosuppressives for those difficult to control (Azathioprine, 6-Mercaptopurine and Remicade)
Surgery - for severe strictures, cancer, abscesses or complicated fistulas; in uncomplicated fistulas - often a nuissance and not treated surgically just treat infections. Even after surgery it is common to have recurrence at the site of surgery.
The above case is a complicated fistula and required surgery.
Diet is designed based on location and severity of disease.

References - emedicine.com and AFIP Radiologic Pathology Course 7th Edition

The Arcuate Sign

2009-04-26T11:27:00.000-07:00

The arcuate sign - is a fracture of the styloid of the fibula at the insertion of the arcuate ligament complex (arcuate ligament, popliteofibular ligament and fabellofibular ligament). It is important because fracture at this site is associated with ACL or PCL tear and posterolateral corner injury. If not caught early can lead to instability, early osteoarthritis and failure of the cruciate ligament repair.

references: http://www.ajronline.org/cgi/content/full/180/2/381 and http://radiology.rsnajnls.org/cgi/content/full/244/2/620

Pleomorphic Xanthoastrocytoma

2009-04-25T19:30:00.000-07:00

We have FLAIR, T1, T2, postcon sag T1 and precon sag T1. The patient was in mid 20's with a history of seizures. The lesion is located near/on the surface of the supratentorial brain. It is cystic with a mural nodule. The nodule is slightly low to brain on T1 and slightly bright to brain on T2 with a avid enhancement.

Differential includes - Meningioma (because the lesion is difficult to exclude that it is not extraaxial), DIG (but the patient is way too old), ganglioglioma, Pleomorphic xanthoastrocytoma, pilocytic astrocytoma, metastasis and oligodendroglioma.

Taking history, age and characteristic imaging appearance the most likely a pleomorphic xanthoastrocytoma.

This is a rare tumor (1% of all brain tumors)

Wide age range in literature - but most in late teens and early 20's

WHO II - but often recurs and not sensitive to chemo or rads

Tx - surgery; If recurs - surgery

Classic appearance - cystic mass with mural nodule that is adjacent to the leptomeninges

However - 52% in literature - no cystic component

Temporal > parietal > frontal > occipital; (10% in more than one lobe)

CT - iso or hypoattenuating lesion on noncon

CT - calcs rare; rare to have erosion of skull or lytic lesions

T1 - iso to hypo to gray matter

T2 - slightly bright or iso to gray

T1 post con - avid enhancement

71% of one series - had involvement of leptomeninges hence can be confused with a meningioma

The peripheral component is single most common feature

Reference - There is an excellent reference to superficial gliomas from the AFIP http://radiographics.rsnajnls.org/cgi/content/full/21/6/1533?eaf - highly recommend reading it.

Images are from Rob's Radiology - please don't take without permission.

Hepatocellular Carcinoma

2009-04-22T19:03:00.000-07:00

The 1st image is CT of liver during arterial phase. The 2nd image is during the portal venous phase and the third is during the delayed phase. This lesion is in a patient with Hepatitis B. With this enhancement pattern, the most likely diagnosis is hepatocellular carcinoma.
Hepatocellular Carcinoma - malignant tumor of hepatocellular origin (duh)

Most common primary malignancy of the liver

Most commonly found in diseased livers - cirrhosis of any cause (such as alcohol), viral hepatitis, and metabolic liver disease (America - alcohol, steroid use, hemochromatosis)

Commonly invade vascular system - especially the portal vein

No fibrous stroma - hemorrhage and necrosis - can rupture and cause hemoperitoneum

3 common growth patterns - solitary, multiple nodules, diffuse infiltrative

Presentation - fever of unknown origin, abdominal pain, malaise, hepatomegaly

AFP can be elevated (and often is - 70-80% or so); like to see >400; >1000 can be presumptive in correct clinical setting

Can produce paraneoplastic syndromes - erythrocytosis, hypoglycemia, hypercalcemia, hirsutism

CT - look for signs of cirrhosis, hemochromatosis etc; arterial - hyper enhancing; PV - iso to hypodense; delayed - often iso maybe hypo - sometimes a capsule is shown

MRI - considered the favored study - T1 - iso, hyper, hypo to liver; T2 - usually hyper; superparagmagnetic iron - may help because no or few kupffer cells;

US - variable appearance and small ones can look like hemangioma (bright/echogenic) - larger are usually heterogenous in echogenicity
Rare associations - thorotrast, primary sclerosing cholangitis, primary biliary cirrhosis, OCP's, 1-antitrypsin deficiency, porphyria cutanea tarda

Treatment - Percutaneous alcohol, RF ablation, TACE but definitive is transplant

Differentials - dysplastic nodules and regenerative nodules. Also consider Hemangioma and focal confluent fibrosis.

Regenerative - rarely 2cm or greater. Can be siderotic or nonsiderotic. Siderotic nodules if large enough are hyperdense nodules in the liver on noncontrast and enhance like normal liver. Siderotic may be dark on T1 and T2 (esp T2). Nonsiderotic might be bright on T1.

Dysplastic nodules - precursor to HCC. Can enhance similar to HCC but don't usually. Often bright on T1 and dark on T2.

references - emedicine.com and Radiographics. 2001;21:S117-S132. Images from Rob's Radiology collection. Please do not copy without permission.

Rob's Radiology

2009-04-21T17:46:00.000-07:00

This is a new foray into information on radiology from my perspective. Hopefully, I will be able to update cases and interesting information. The image to the left is a fascinating case of a patient with rupture of abdominal aortic aneurysm where you can actually see the blood squirt through the defect into the peritoneum.