Faculty Bibliography

OBJECTIVE AND IMPORTANCE: We present a patient who experienced a subarachnoid hemorrhage secondary to a dissecting aneurysm of the right posteroinferior cerebellar artery (PICA). The use of an encircling clip in treating the aneurysm while preserving supply to brain stem perforators originating near the dissecting segment and the distal PICA territory was key in the operative management. CLINICAL PRESENTATION: A 48-year-old patient with a history of hypertension presented with subarachnoid hemorrhage confirmed by computed tomography of the brain. Successive cerebral angiography revealed a dynamic change in the configuration of the dissection, with expansion of the associated focal ectasia. OPERATIVE MANAGEMENT: At surgery, three brain stem perforators adjacent to the aneurysm were visualized. The dissecting segment was reconstructed with an encircling Sundt clip and muslin wrap, which preserved the flow through the PICA and brain stem perforators. CONCLUSION: A patient suffering from a dissecting PICA aneurysm and subarachnoid hemorrhage was successfully treated with direct surgical reconstruction of the parent artery, sparing the perforators to the medulla

PURPOSE: Our goal was to evaluate non-breath-hold Gd-enhanced 3D MR angiography (MRA) for the detection of atherosclerotic occlusive disease of the aortic arch vessels and to compare image quality with two breath-hold techniques. METHOD: One hundred sixty consecutive patients with known or clinically suspected atherosclerotic cerebrovascular occlusive disease underwent Gd-enhanced 3D MRA of the aortic arch and great vessels. One hundred twenty-six examinations were performed with the body coil after infusion of 40 ml of Gd-DTPA; 89 of these were performed without breath-holding and 37 were acquired during suspended respiration. Thirty-four examinations were performed in a body phased-array coil with breath-holding, a timing examination, and 20 ml of contrast agent by manual (n = 17) or power (n = 17) injection. Images were evaluated for the presence of blurring and ghosting artifacts and venous enhancement. Of the 27 patients who underwent non-breath-hold MRI and digital subtraction angiography (DSA), two readers blinded to the DSA results retrospectively evaluated the MRA examinations for the presence of occlusive disease of the innominate, carotid, subclavian, and vertebral arteries. DSA correlation was not evaluated for the 71 breath-hold studies. RESULTS: Sensitivity and specificity for arch vessel occlusive disease with non-breath-hold MRA were 38 and 94% for Reader A and 38 and 95% for Reader B. Breath-holding significantly reduced blurring and ghosting artifacts (p < 0.001) when compared with non-breath-hold imaging, and use of 20 ml of contrast medium, with a timing examination, resulted in significantly less venous enhancement than seen with 40 ml (p < 0.001). CONCLUSION: Non-breath-hold Gd-enhanced 3D MRA is insensitive for detecting arch vessel occlusive disease. Breath-hold imaging, in conjunction with a timing examination and a lower dose of contrast agent, improves image quality, but further studies are needed to assess diagnostic accuracy

The authors examined interhemispheric memory transfer in 32 patients with lateralized temporal lobe complex partial epilepsy (15 right onsets, 17 left onsets). Visually presented verbal, nonverbal, and two types of dually encodable stimuli were displayed during amobarbital anesthesia, and recognition memory was tested with verbal and nonverbal (pointing) response modalities. No relationship was found between the material specificity of stimuli and response modality. The only significant findings were for poorer recognition memory after injection of the hemisphere contralateral to the seizure focus. Visual information presented predominantly to one hemisphere during anesthesia is available to the other hemisphere for recognition memory on clearing

Arteriovenous fistula of the scalp secondary to punch autograft technique is a relatively uncommon occurrence, similar to traumatic scalp arteriovenous fistulas from other causes. A pulsatile subcutaneous mass with an associated thrill or bruit and symptoms including pain or headache is a common presentation. Angiography is required for full diagnostic evaluation. Angioarchitecture may appear complex, even with a single-hole fistula. Super-selective angiography and embolization facilitate surgery and provide essential information regarding angioarchitecture. Complete excision of the lesion is curative. Identification and resection of the draining vein is mandatory to ensure a complete resection. The lesion may extend across traditional anatomic planes. Ligation of proximal feeding arteries is inadequate and potentially harmful. Histopathology of the traumatic arteriovenous fistula may appear similar to that of an arteriovenous malformation. Acquired arteriovenous fistulas and congenital arteriovenous malformations are markedly similar in their ultimate histopathology, angioarchitecture, angiographic appearance, hemodynamics, and treatment requirements. They should be considered to represent a spectrum of the same disease state rather than discrete entities

There is considerable variability among epilepsy centers in the methods and interpretations of the intracarotid amobarbital procedure. Prominent among these differences is the determination of language representation and assessment of language functions. Some centers rely on speech arrest following amobarbital injection as a marker for language representation, whereas other centers examine verbal output for the presence of aphasic errors. The present study assessed the pattern of language recovery following amobarbital injection in epilepsy patients who were candidates for temporal lobectomy. Language recovery from dominant hemisphere injection (left or right) followed a stereotypical progression, with 71.8% of patients showing return of vocalization followed by return of naming and comprehension. Repetition deficits with paraphasic errors persisted the longest (mean = 12'30'), with a conduction aphasia persisting after the acute global aphasia resolved. Although two patients interpreted as left hemisphere language dominant were mute following right hemisphere injection, all language functions were intact immediately upon resumption of vocalization and they showed no other signs of aphasia such as paraphasias or anomia. Possible explanations for serial language recovery and persistent conduction aphasia are discussed. These findings have significant implications for the determination of cerebral language dominance

Although computed tomography and, more recently, magnetic resonance imaging, have supplanted pneumoencephalography and angiography in the initial evaluation of patients with suspected intracranial neoplasms, angiography may still have an important role in the diagnosis and management of such individuals. It can define normal arterial and venous anatomy (important information in planning surgical approaches to some lesions), show vascular abnormalities associated with intracranial tumors, evaluate the integrity of the collateral circulation, incorporate functional testing for eloquent brain in the vicinity of a lesion, and be used in conjunction with the administration of intra-arterial chemotherapy

Magnetic resonance and computed tomographic angiography have been increasingly applied to the study of disease affecting the cerebral vasculature. Despite these advances, however, conventional cerebral angiography clearly remains the diagnostic gold standard and essential guide to any microneurosurgical or endovascular therapeutic decision concerning cerebral aneurysms. Detailed cerebral angiography is a dynamic study and is influenced by prior axial imaging. It should be tailored to the specific circumstance to obtain information required for selection of the most beneficial treatment

Spinal angiography is an infrequently performed radiologic procedure requiring much skill and knowledge for its proper application. Most commonly, spinal angiography is used in the diagnosis of spinal arteriovenous malformations and in the delineation of vascular tumors of the spinal cord. Less usual indications may include preoperative evaluation of the spinal cord vasculature prior to surgeries involving the descending thoracic aorta or ventrolateral approaches to the spine, particularly in patients undergoing repeat operations. Spinal angiography should address three crucial considerations for the surgeon or neurointerventionalist: (1) the exact location and anatomic configuration of the lesion, (2) the vascularity of a lesion and identification of all feeding and draining vessels, and (3) depiction of the regional vascular anatomy of the spinal cord in relation to the lesion. Considering the relatively longer length of the procedure, larger contrast volumes, and increased complexity (as measured by catheter exchanges required) of spinal angiography, however, certain angiographic techniques (e.g., digital subtraction angiography, the use of general anesthesia, or placement of a groin sheath to facilitate catheter exchanges) and the use of low osmolality contrast agents should be considered to improve the quality of the examination while reducing risk

PURPOSE: To assess the safety of high-dose nonionic contrast media (CM) during a single radiologic procedure. MATERIALS AND METHODS: From November 1991 to August 1995, 255 high-dose angiographic procedures were performed in 228 patients with normal serum creatinine (SCr) levels (< or = 1.6 mg/dL [141 mumol/L]). All patients received 250-800 mL low-osmolarity CM (300 mg iodine per milliliter). Pre- and postprocedure SCr levels were assessed. Urine output was measured daily in the 75 patients who received more than 400 mL CM. With linear regression analysis, a dose-related elevation in SCr levels was calculated. RESULTS: No patient developed abnormal SCr levels (> 1.6 mg/dL [141 mumol/L]) as a result of the CM. Among the patients who received more than 400 mL, none developed oliguria over the first 36 hours. With follow-up up to 3 years, no patient experienced delayed clinical renal failure. In 11 (4.3%) patients, the SCr levels increased more than 25%, but all increases were within expected limits (chi 2 analysis). Linear regression analysis revealed a 0.015 mg/dL (1 mumol/L) increase in SCr levels per 100 mL CM. CONCLUSION: Intravenous administration of high-dose low-osmolarity iodinated CM appears safe in patients without renal dysfunction or other underlying risk factors, in doses as large as 800 mL (300 mg iodine per milliliter)