Posterior Cerebral Venous Circulation

Get out your 3d glasses.  This is just a quick anaglyph I extracted from an MR to demonstrate the anatomy of the posterior cerebral venous circulation and practice using Slicer, a nice open source visualization tool available at www.slicer.org. As always, select the image for a larger view.

Update: All is well at UTMC.  We are interviewing residency candidates now and they are all top notch.  The department has undergone a nice renovation.

Dural AVM

CTA: posterior fossa vascular malformation. Prominant subarchnoid venous varices near the torculum (red) and menigeal arterial branches (blue)

A dural arteriovenous malformation is an abnormal connection between a meningeal artery and a meningeal vein or dural venous sinus.


Type I dural arteriovenous malformation are suppied by meningeal arteries and drain into a meningeal vein or dural venous sinus. The flow within the draining vein or venous sinus is anterograde.


The high pressure within a Type II dural AV malformation causes blood to flow in a retrograde fashion into subarachnoid veins which normally drain into the sinus. Typically this is because the sinus has outflow obstruction. Such draining veins form venous varices or aneurysms which can bleed. Type II  malformation need to be treated to prevent hemorrhage. The treatment may involve embolization of the draining sinus as well as clipping or embolization of the draining veins.


Type III dural AV  malformation  drain directly into subarachnoid veins. These veins can form aneurysms and bleed. Type III dural malformation need to be treated to prevent hemorrhage. Treatment can be as simple as clipping the draining vein at the site of the dural sinus. If treatment involves embolization, it will only typically be effective if the glue traverses the actual fistula and enters, at least slightly, the draining vein.

Perthe's Lesion

MR Arthrogram:  Avulsed anterosuperior cartilagenous labrum with periosteal stalk still attached to glenoid

A variation of the Bankart lesion, the Perthes lesion occurs when the scapular periosteum remains intact but is stripped medially, and the anterior labrum is avulsed

from the glenoid but remains partially attached to the scapula by the intact periosteum. Sometimes the laburm settles into its normal position but is detached and unstable.  This type of Perthes lesion may be difficult to diagnose.  This example is displaced and easier to identify.

Traumatic Aortic Tear

CTA chest: Aortic tear at ligamentum arteriosum level with extensive RT hemothorax

Up to 15% of all deaths following motor vehicle collisions are due to injury to the thoracic aorta.  The proximal descending aorta, where the relatively mobile aortic arch can move against the fixed descending aorta at theligamentum arteriousm, is at greatest risk from the shearing forces of sudden deceleration.Chest X-ray is still used as the primary screening study, but has a low sensitivity. The sensitivity of modern CT scanners is reported at 97-100%, with a negative predictive value of 100% and specificity of 83-99%. Many surgeons  rely solely on the CT scan to plan operative or endovascular repair. Endovascular repair of thoracic aortic injury is available.

Reference: trauma.org 9:4, April 2004 Chest Trauma: Traumatic Aortic Injury

Ulcerative Colitis

Fig 1. coronal CT abdomen and pelvis. Mildly distended colon with loss of haustral markings.






Fig 2. Coronal 3d. featureless, lead pipe colon

Ulcerative colitis is a type of inflammatory bowel disease. It involves the large intestine with characteristic ulcers. Symptoms include bleeding and diarrhea. Like Crohns, Ulcerative colitis is an intermittent disease, with periods of active disease and periods that are asymptomatic.

Ulcerative colitis occurs in less than 0.1% of the population. The disease is more prevalent in northern countries. Ulcerative colitis has no definIte cause. These appears to be a genetic component. Treatment is with anti-inflammatory drugs, immunosuppression, and biological therapy targeting specific components of the immune response. Colectomy (partial or total removal of the large bowel through surgery) is occasionally necessary, and is considered to be a cure for the disease.

In patients with long standing disease, a lead-pipe colon can develop. There is hypertrophy of the muscularis mucosa. The thickened muscle layer gives the colon a narrowed ahaustral form. Strictures may also narrow the lumen.


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Caput Medusae

VR image of abdominal wall in a patient with cirrhosis and portal venous hypertension.  Inset is Head of Medusa from God of War II (Sony)

Distended and engorged paraumbilical veins, radiating from the umbilicus across the abdomen to join systemic veins. The name caput medusae (Latin for "head of Medusa") originates from the apparent similarity to Medusa's hair once Athena had turned it into snakes. It is a sign of severe portal hypertension that has decompressed by portal-systemic shunting through the paraumbilical veins. DDX would include IVC obstruction which can also produce abdominal wall collateral veins.

Sorry it has ben a while since last post .

Struma Ovarii

Ultrasound shows a large complex solid and cystic mass  in the RT ovary, which was a mature teratoma.  Pathology shows follicular glands filled with colloid interspersed throughout the tumor

Struma ovarii is a rare ovarian tumor defined by the presence of thyroid tissue comprising more than 50% of the overall mass, usually as part of a teratoma, but sometimes as part of a serous or mucinous cystadenoma. They make up approximately 1% of ovarian tumors. They are benign about 2/3 ‘s of the time. Thyrotoxicosis is seen in 5%. Surgical resection is the treatment.


Yoo SC, Chang KH, Lyu MO, Chang SJ, Ryu HS, Kim HS. Clinical characteristics of struma ovarii. J Gynecol Oncol. Jun 2008;19(2):135-8.