James B. Naidich

Case report 872

A case of an ancient schwannoma was presented. The rare occurrence of this tumor has resulted in only a few reported cases with descriptions of its features on imaging. Our patients tumor, like one previously reported case, demonstrated calcification on the plain film - a finding not associated with other histologic types of schwannomas. Angiography revealed the tumor to be hypervascular. Evaluation by MRI demonstrated a lobulated, encapsulated soft tissue mass containing several cystic areas that corresponded histologically to areas of necrosis. Hypertrophied blood vessels were seen in the periphery of the tumoral mass. Too few ancient schwannomas have been reported to conclude whether or not radiographic evidence of soft tissue calcification is characteristic of this histologically distinctive subtype of schwannoma. However, since calcification is seen histologically as part of the degenerating process, its presence on plain films could be a feature of this tumor. Furthermore, the presence of cystic areas on MRI is not surprising given the pathological changes that occur in this tumor. We suggest that a diagnosis of ancient schwannoma be considered when a patient presents with a hypervascular soft tissue mass containing amorphous calcification on plain films and cystic areas on MRI. Despite the nonspecificity of these imaging findings, this point is relevant because each of these features suggests the presence of a malignant mass. Awareness of the possibility of a benign ancient schwannoma could obviate unnecessary radical surgery.

Doppler Sonographic Criteria for the Diagnosis of Inferior Mesenteric Artery Stenosis

Objective. The purpose of this study was to define the optimal Doppler criteria for the diagnosis of inferior mesenteric artery (IMA) stenosis in patients with suspected chronic mesenteric ischemia (CMI). Methods. A retrospective review of 205 dedicated color and pulsed Doppler sonographic studies of mesenteric arteries was performed in 205 patients. All studies were performed in patients with suspected CMI. Correlative angiography was available in 50 patients. Results. The IMA was visualized in 176 of 205 Doppler sonographic examinations (86%) and in 92% of the correlative studies. The visualization rate for the detection of a patent IMA by Doppler sonography in this series was 90%. The ranges of the peak systolic velocity (PSV), end‐diastolic velocity (EDV), and mesenteric‐aortic velocity ratio (MAR) in the nonstenotic IMA were 70 to 200 cm/s, 0 to 33 cm/s, and 0.7 to 3.7, respectively. The ranges of the PSV, EDV, and MAR in IMA stenosis were 200 to 485 cm/s, 0 to 177 cm/s, and 0.69 to 8.1. The threshold values for severe IMA stenosis by logistic regression analysis (n = 42) were as follows: PSV, greater than 200 cm/s; EDV, greater than 25 cm/s; and MAR, greater than 2.5, with sensitivities of 90%, 40%, and 80%; specificities of 97%, 91%, and 88%; positive predictive values (PPVs) of 90%, 57%, and 67%; negative predictive values (NPVs) of 97%, 83%, and 93%; and accuracy of 95%, 79%, and 86%, respectively. Conclusions. We found that a PSV of greater than 200 cm/s was the best criterion for the diagnosis of IMA stenosis. The sensitivity, specificity, PPV, NPV, and accuracy for the PSV were 90%, 97%, 90%, 97%, and 95%, respectively.

Computed tomographic evaluation of therapeutically induced changes in primary and secondary brain tumors.

SummaryA prospective study was initiated to evaluate computed tomography as a method for monitoring therapeutically induced changes in brain tumors. Early postoperative scans may be misleading in the evaluation of residual tumor because of trauma to the blood-brain barrier during operation. The size of the dominant mass (17/25), enhancement (11/25), edema (11/25), and ventricular distorition (14/25) were decreased in many patients after radiation therapy. Occasional tumors increased in size during radiation therapy (3/25). Enlargement of the lateral ventricles developed in 9 of 25 patients. Computed tomography offers definite advantages over nuclide brain scans, angiography and other diagnostic studies for evaluating therapeutically induced changes in brain tumors.

Computed tomography in ossification of the posterior longitudinal spinal ligament

SummaryA patient with cervical myelopathy was found to have extensive ossification within the posterior longitudinal ligament. Computed tomography of the spine was of value for precisely defining the degree of narrowing of the spinal canal. The nature of this disease entity is discussed.

The widened interspinous distance: a useful sign of anterior cervical dislocation in the supine frontal projection.

Anterior dislocation of the cervical spine may be detected reliably in the supine frontal projection by evaluating the cervical spinous processes. A widened interspinous distance (ISD) which measures more than one and one-half times the ISD above and more than one and one-half times the ISD below indicates the presence of an anterior cervical dislocation at the level of abnormal widening. Measurements of the interspinous distances from the C3-C4 interval through the C7-T1 interval in 500 patients with normal cervical spines and in 14 patients with documented anterior cervical dislocations revealed neither false positive nor false negative diagnoses by these criteria.

Idiopathic arterial calcification of infancy: a case with prolonged survival

We describe a patient with idiopathic arterial calcification of infancy and the following unusual features of the disease: (1) prolonged survival until age 11 years, (2) discordance between the extent of vascular calcification and clinical manifestations of arterial luminal occlusion, (3) a large area of myocardial calcification, (4) symptoms of cerebral-vascular insufficiency, and (5) spontaneous resolution of hypertension.

The value of MRI in evaluating perirectal and pelvic disease

MRI of the perirectal region is facilitated by the superb soft tissue contrast, multiplanar imaging capability, lack of respiratory motion artifact and absence of clip artifact which can hamper visualization by CT scan. MRI provides distinct advantages over CT scanning without the need for ionizing radiation or the injection of intravenous contrast material. This study reviews the findings in 18 consecutive patients with a variety of perirectal pathologies including rectal carcinoma (3), gynecologic neoplasm (8), sacral lesions (2), pelvic arteriovenous malformations (2), inflammatory bowel disease (2), and a pelvic kidney (1). In the perirectal region, MR was useful to show normal tissue planes, benign processes which can mimic neoplasm, intrapelvic extension of malignancy and adenopathy.

PARASITIC LUMBAR ARTERIAL BLOOD SUPPLY IN RENAL ANGIOMYOLIPOMA

A young woman with azotemia was found to have an angiomyolipoma which had parasitic blood supply from a lumbar artery. Parasitic lumbar arterial blood supply from a lumbar artery. Parasitic lumbar arterial blood supply has previously been considered a strong indication of malignancy. Since this benign lesion had not invaded the adjacent retroperitoneal structures, the phenomenon tends to confirm the postulate that parasitic blood supply to a lesion may occur through hypertrophy of small anastomotic channels normally present between adjacent vessels but not normally seen in angiography.

Double Microcatheter Single Vascular Access Embolization Technique for Complex Peripheral Vascular Pathology

The authors describe an embolization technique that allows safe, controllable exclusion of complex vascular pathologies using a single vascular access and 2 microcatheters. This technique is particularly useful in situations where high flow increases the risk of coil migration and nontarget embolization and in large aneurysms. It affords precise placement and repositioning of coils. This method was used to treat patients with pulmonary arteriovenous malformations, renal arteriovenous fistulae and aneurysms, visceral arterial aneurysms and pseudoaneurysms, an aortic pseudoaneurysm, and occlusion of native parent vessels. The technique facilitated safe and successful endovascular closure in all cases.

Isolated Intrathoracic Injury with Air Bag Use

The restrained (air bag and seatbelt) driver of a vehicle involved in a high-speed motor-vehicle accident sustained a tear of the thoracic aorta with no signs of external injury. Air bag deployment may mask significant internal injury, and a high index of suspicion is warranted in such situations.