Faculty Bibliography

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)

We examined the efficacy of a memory difference score (DS: right minus left hemisphere memory) during the Wada test (intracarotid amobarbital procedure, IAP) for predicting seizure laterality and postoperative seizure outcome in 70 left speech dominant patients from two epilepsy centers. DS > or = 2, after addition of 1 point to the left hemisphere injection score to account for aphasia, were noted in 71.4% of patients and correctly predicted surgery side for 98.0% of these patients. The DS related significantly to seizure outcome at 1-year follow-up (p < 0.002) and correctly predicted 80% of patients who were seizure-free. Patients whose DS did not correctly predict seizure laterality more frequently required invasive studies to establish seizure onset. The relationship of the DS to laterality did not differ significantly by class of IAP memory stimuli. When seizures originate from the temporal lobe, the IAP memory DS predicts seizure laterality by assessing the functional adequacy of the involved hemisphere and is predictive of seizure control

Intracranial DAVFs are most commonly found in the cavernous, transverse, and sigmoid sinuses. MR imaging and MR angiography can be used to screen for these lesions and determine if there is cortical venous drainage. Conventional angiography still has a major role in screening and is mandatory prior to any therapy. Spinal DAVFs are uncommon lesions seen predominantly in older men. The diagnosis can be suspected with MR imaging if a large draining vein is seen in association with swelling and enhancement of the conus and increased signal on T2-weighted images. MR angiography shows some promise in identifying the vascular anatomy of these lesions

OBJECTIVE: To determine behavioral correlates of anterior cerebral artery (ACA) and posterior cerebral artery (PCA) perfusion patterns in the intracarotid amobarbital sodium procedure. DESIGN: Multivariate analysis of covariance and partial correlations of behavioral measures to ACA crossflow and PCA filling. SETTING: Angiography and the intracarotid amobarbital procedure at a comprehensive epilepsy center. SUBJECTS: Forty-two patients with intractable epilepsy (right-hemisphere seizure focus [n-23]; left-hemisphere seizure focus [n = 19]). MEASUREMENTS: Internal carotid angiography was performed both at a standard injection rate (8 mL of contrast per second) and at 1 mL/s, which matched the rate of the subsequent amobarbital injection. The degree of ipsilateral PCA and contralateral ACA filling were graded on a seven-point scale and compared with postinjection behavior, language, and memory measures. RESULTS: The ACA crossflow did not correlate significantly with that of any measure. The degree of PCA-filling pattern correlated significantly only with the level of consciousness (r = .31, P < .004), but it was not significant after accounting for the effects of seizure laterality, injection side, and amobarbital dosage. Neither ACA crossflow nor PCA filling correlated significantly with memory. The degree of ACA and PCA filling was overestimated at standard angiography (8 mL of contrast medium per second) injection rates. CONCLUSIONS: Although the degree of PCA filling correlates mildly with the level of consciousness postinjection, possibly by perfusion of thalamic or mesencephalic branches, it is not reliably predictive and is less contributory than the injection side and seizure laterality. The PCA filling is not required to produce valid memory assessment in the intracarotid amobarbital procedure, and ACA crossflow is not predictive of behavioral responses

Most meningiomas are benign and therefore curable lesions. Currently, the best available treatment is complete surgical resection. Toward this end, interventional neuroradiologists should contribute to the efficient and total removal of tumor mass. Although some controversy exists as to the value of the embolization of meningiomas involving the convexity, preoperative embolization certainly is of value in more complex presentations, including giant meningiomas, meningiomas exhibiting malignant or angioblastic characteristics, as well as those involving the skull base, scalp, or critical vascular structures. Several reports have illustrated the importance of preoperative embolization in reducing blood supply to lesions in surgically inaccessible areas. Moreover, several arguments may be advanced in defense of embolization as a method of devascularization superior to dural vessel ligation at the time of operation. Microemboli enter the vascular bed of the tumor and devascularize the lesion irrespective of collateral circulation. In addition, bilateral dural devascularization is easier to accomplish via endovascular techniques and may obviate the need for surgical exposure of the contralateral side during resections of tumors involving the falx or parasagittal region. The tumor necrosis occurring after devascularization by microparticulate emboli may facilitate surgical manipulation. At a theoretical level, embolization may reduce the likelihood of recurrence, particularly from unnoticed invasion of dural venous sinuses or from the surrounding dura. To achieve these goals, embolization should be as complete as possible. This requires a thorough understanding of the disease process and the vascular anatomy involved and superb technique