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Star Wars IV: The Force Takes Chewbacca

Another fun trivia question for Washington Redskins fans. In 1974, the Washington Redskins offered a professional wrestler a contract to play professional football. The wrestler turned down the football contract to make far more money as a wrestler. Which wrestler was offered a contract by the Redskins?

As you walk the Hollywood Walk of Fame, you pass by the beautiful and historic Grauman's Chinese Theater. Every day, you can walk by the theater and see panhandlers dressed up as stars such as Marilyn Monroe and Superman, offering to pose with tourists for a nominal fee.

Well, sometimes the panhandlers can be a bit aggressive. In probably the best news story ever, a 6-foot 4-inch tall man, dressed in a hairy Chewbacca costume was aggressively offering to pose for a picture with two asian tourists on a guided tour. The tour guide did not appreciate Chewbacca bothering his customers, so he yelled "Stop bothering the tourists!"

Infuriated by the tour guide's comment, Chewbacca screamed "NOBODY TELLS THIS WOOKIEE WHAT TO DO!" and proceeded to headbutt the tour guide. Chewbacca was then arrested by police and taken away in his giant hairiness.

Well, that news story was a great segue into the answer to the trivia question. Both Chewbacca and the wrestler were hairy, large and had very little grasp of the english language. Nobody got this one, huh? Oh well, the answer is Andre the Giant. And for those of you who still don't know who he is, he's the big guy from "The Princess Bride" movie.

Developmental venous anomaly

Findings

Initial noncontrast head CT (Figure 1) shows abnormal hyperdensities within the right Sylvian fissure and adjacent insular cortex, raising the possibility of a vascular malformation.
Follow-up T2-weighted MR image (Figure 2) shows multiple linear increased signal intensity foci in the deep white matter converging near the ventricular surface. These represent dilated medullary veins of the caput medusa.
Cerebral angiography during the arterial phase (Figure 3) is normal while the venous phase (Figure 4) shows umbrella-like medullary veins converging on two collector veins (red arrows in Figure 4) which then empty into a normal venous system.


Diagnosis: Developmental venous anomaly


Developmental venous anomaly (DVA), also known as venous malformation or venous angioma, refers to aberrant venous development and is composed of a network of dilated medullary veins converging in a radial or umbrella-like fashion onto a large collector vein. The collector vein follows an aberrant course to empty into normal superficial or deep veins. A DVA can occur in the cerebrum, cerebellum, or brainstem and is characterized by normal intervening parenchyma. As it is a normal variant, clinically significant hemorrhage is unusual and should raise the possibility of a concomitant cavernous angioma or other vascular malformation.

On CT, a small DVA may not be visualized; however, a large DVA may be seen as a hyperdense lesion.

Blood flow within DVAs is slow, which produces fluid-like signal intensity rather than flow void on MR imaging. Strong contrast enhancement is typical; the lack thereof should raise doubt about the diagnosis of DVA.

On cerebral angiography, the classic “Medusa head” appearance is visualized on the venous phase, with the arterial and capillary phases normal.

Myeloma with cord compression

Findings

Sagittal T1-image (Figure 1) in a patient with multiple myeloma shows a large epidural mass in the midthoracic region with associated cord deformity. The mass displaces the epidural fat. Postsurgical changes are seen in the lower spine consistent with repair of a prior compression deformity. Marrow signal is heterogeneous throughout.
Sagittal T2 image (Figure 2) in a patient with multiple myeloma shows a large epidural mass in the mid-thoracic region with associated cord deformity. The normal CSF signal is completely displaced by the mass. Post-surgical changes are seen in the lower spine consistent with repair of a prior compression deformity. Marrow signal is heterogeneous throughout
Post-contrast T1 axial image (Figure 3) demonstrates compression of the cord anteriorly by a large epidural mass.


Diagnosis: Myeloma with cord compression


Myeloma patients with abnormal neurological findings suggesting cord compression should be evaluated by MRI when available. Imaging exam should be primarily targeted, based on the results of motor and reflex tests, rather than pain or sensory level.
Spinal cord compression is a neurological emergency that may be diagnosed by the presence of a mass lesion abutting the cord with cord deformity, or abnormal cord T2-signal.

Acute spinal cord compression is a potentially devastating neurological emergency that requires both prompt diagnosis and intervention to prevent permanent impairment. The frequency of metastatic cord compression is increasing as cancer prevalence rises and new treatment modalities prolong patient survival. Close cooperation between clinical services and diagnostic radiologists is essential for patient triage. This is especially true in cases where patients cannot be fully examined neurologically. Magnetic resonance imaging is the study of choice in evaluating these patients; it is noninvasive, does not involve radiation, and provides for investigation of both osseous and soft tissue lesions.

Many etiologies can result in acute spinal cord compression. These include trauma, infection, neoplasm, degenerative disc disease, and others. Differentiation between these various causes of acute cord compression relies on a combination of clinical history, neurological exam, and imaging findings. However, the constellation of imaging findings indicative of cord compression are similar, regardless of the causative process.

In evaluating the patient, close cooperation between clinical staff and the diagnostic radiologist is essential. Information from the neurological exam is critical for localization of the lesion and optimization of the imaging protocol. Whole spine imaging is generally undesirable as it is more time-consuming, expensive, and difficult for patients who are often in considerable pain. It further lowers resolution on exams that are often suboptimal, secondary to severe patient pain and patient movement. Spinal sensory levels on neurological examination may be up to several segments below the anatomic level of cord compression. Evaluation of motor function and reflexes is very useful for lesion localization.

There has been considerable debate within the literature on the precise radiological definition of cord compression. Animal models suggest that both direct mass effect on the cord and impingement on the epidural venous plexus contribute to pathology. Spinal cord compression may be defined as the presence of a mass lesion abutting the cord with the complete loss of intervening CSF. This must be accompanied by deformation of the spinal cord, or the presence of signal changes within the cord. The findings are best visualized on T2-weighted images. If the patient is concurrently symptomatic, acute intervention is mandated with the specific type of intervention determined by the underlying disease process.

Supraclinoid Aneurysm- A Case Report

Case Submitted by Dr MGK Murthy Sr Consultant Teleradiology Providers

Case Details and Discussion

55 yr old lady complains of chronic headache of 10 yrs duration with increasing severity
she is normotensive and has no neurological deficit Routine MRI shows well defined regular heterogenous altered signal intensity extraaxial lesion in left paracavernous and supraclinoid locations with an intensely enhancing nodule within on contrast as well as hypointense periphery with no significant perilesional oedema- likely to be partially thrombosed internal carotid giant aneurysm with thrombus within. DSA is the solution. At times Meningimas which are cystic, haemangioblstomas and pilocytic astrocytomas could present a diagnostic difficulty. However intense nodular enhancement, lack of perilesional oedema, chronic headache of long duration with no deficit are supportive of aneurysm. Supraclinoid component is suggested as intracavernous ICA appears compressed and shows normal flow void.

MRI features in Placental Invasion

The value of specific MRI features in the evaluation of suspected placental invasion by Lax A et al in Magn Reson Imaging 2007 Jan;25(1):87-93. Epub 2006 Nov 14 points out that MRI can be a useful adjunct to ultrasound in diagnosing placenta accreta prenatally. Three features that are seen on MRI in patients with placental invasion appear to be useful for diagnosis: uterine bulging; heterogeneous signal intensity within the placenta; and the presence of dark intraplacental bands on T2W imaging.

Craniopharyngioma

Findings

There is a well-circumscribed suprasellar mass that is predominantly cystic with focal rim calcifications (Figure 1).
The pituitary gland appears normal (Figure 2). Fluid-fluid level is noted with bright signal on T1-WI (Figure 3), T2-WI and FLAIR (Figure 4 and Figure 5). Post contrast image show minimal enhancement along the periphery of the lesion with no enhancement of the lesion itself.


Diagnosis: Craniopharyngioma


Key points

Craniopharyngiomas are benign dysodontogenic epithelial tumors derived from Rathke pouch epithelium. These tumors are mostly suprasellar (75%), with intrasellar extension seen in 20% of cases.

Two types of Craniopharyngioma are classically described:
1) Childhood form- Peak 5-15 years. Has cyst formation and calcification. Has an adamantinomatous microscopic pattern and carries poor prognosis.
2) Adult form- Peaks in sixth decade. Shows papillary squamous epithelium. Symptoms are usually due to mass effect-headache, visual disturbances, behavioral changes, hydrocephalus, and endocrine dysfunction.

Craniopharyngiomas are WHO Grade I lesions. These are multilobulated, multicystic masses. The cyst may contain variations of highly proteinaceous fluid, cholesterol, and blood products.

On CT, these appear as large, lobulated heterogeneous suprasellar masses. Intrasellar extension may enlarge the sella and cause erosion of dorsum sellae. Cysts may vary in density, depending on contents. Calcification may be peripheral or irregular and nodular.

High-signal intensity within a suprasellar mass should raise suspicion of craniopharyngioma. Cyst contents are typically hyperintense on T2 and FLAIR images. Enhancement is heterogeneous in the solid portion of the tumor, with the cyst walls enhancing strongly. Cyst contents show a broad lipid spectrum on MRS (0.9 ppm to 1.5 ppm). Infiltration is common, making complete surgical resection difficult.