Anatomic correlates of memory from intracarotid amobarbital injections with technetium Tc 99m hexamethylpropyleneamine oxime SPECT.

OBJECTIVE: To better identify regions of the brain affected by intracarotid amobarbital injections and to more precisely predict whether resections of specific brain regions will cause postoperative memory deficits. DESIGN: We modified the standard intracarotid amobarbital procedure by adding a radioactive tracer to the amobarbital injection, thereby providing better correlation between behavior and deactivated brain region. SETTING: Tertiary-care hospital center with a dedicated program for medical and surgical treatment of epilepsy. PATIENTS: We studied 39 patients with medically intractable epilepsy drawn from a regional referral base. INTERVENTION: Intracarotid injection of 125 mg of sodium amobarbital with 37 MBq of technetium Tc 99m hexamethylpropyleneamine oxime (HMPAO), followed by language and memory testing. MAIN OUTCOME MEASURES: The distribution of amobarbital as measured by single photon emission computed tomographic imaging of HMPAO and patient performance on memory tasks. RESULTS: Medial temporal regions were irrigated by the amobarbital in only 28% of the injections. Overall, findings suggest that medial temporal and lateral neotemporal cortex play a role in memory. CONCLUSIONS: The regions involved in memory function vary by individual, as does the distribution of amobarbital. Thus, the most accurate method of determining correlation of brain region with memory function during intracarotid amobarbital injection involves the use of a tracer such as HMPAO.

Arterial changes after thrombolysis and percutaneous transluminal angioplasty in vertebrobasilar thrombosis.

We present clinicopathologic findings in a patient treated with intraarterial thrombolysis and angioplasty for vertebrobasilar thrombosis. Autopsy revealed a marked inflammatory infiltrate within the vertebral artery at the site of catheter manipulation. This finding may have important implications for the use of interventional angiography in cerebrovascular disease.

Histologic abnormalities associated with gadolinium enhancement on MR in the initial hours of experimental cerebral infarction.

PURPOSE: To determine the histologic changes associated with gadopentetate dimeglumine enhancement on MR images in acute focal cerebral ischemia. METHODS: In each of two baboons, a microcatheter was used to occlude partially the middle cerebral artery and reduce cerebral blood flow for approximately 3.5 hours. The catheter was then removed allowing reperfusion for approximately 3.5 hours. In two other baboons, cerebral blood flow was completely and irreversibly interrupted by injecting liquid adhesive into the middle cerebral artery. T2-weighted and serial enhanced T1-weighted MR images were obtained. Brain specimens were studied histopathologically. RESULTS: In the animals with incomplete and reversible reduction of cerebral blood flow, postcontrast T1-weighted images obtained during the initial 3 hours of ischemia showed focal areas of hypointensity. These areas were enhanced on later images. The areas of signal abnormality were subsequently found to be necrotic and were characterized by neuronal cytolysis and vascular "plugging." In the animals with complete and irreversible interruption of cerebral blood flow, no abnormal signal intensity or enhancement was observed. Histologic abnormalities were milder in these animals. CONCLUSIONS: Contrast enhancement on MR images in the initial hours of cerebral ischemia was associated with histologic evidence of tissue necrosis but was not associated with milder ischemic changes.

Treatment of dural carotid-cavernous fistulas via the superior ophthalmic vein.

Symptomatic patients with dural carotid-cavernous fistulas often require treatment. Traditional therapies, which often are not completely successful, include manual common carotid artery compression and embolization via transarterial routes. This report describes four symptomatic patients with spontaneous dural carotid-cavernous fistulas who were treated unsuccessfully with transarterial embolotherapy and subsequently treated successfully by having a detachable balloon introduced into the cavernous sinus via the superior ophthalmic vein, which was surgically exposed. The fistulas resolved without complications. Treatment of dural carotid-cavernous fistulas by means of the transvenous approach via the superior ophthalmic vein may be of benefit in selected patients.

Giant serpentine aneurysms: a review and presentation of five cases.

We present five cases of giant serpentine aneurysms (large, partially thrombosed aneurysms containing tortuous vascular channels with a separate entrance and outflow pathway) and review 28 cases reported in the literature. Giant serpentine aneurysms should be considered as a subgroup of giant aneurysms, distinct from saccular and fusiform varieties, given their unique clinical presentation and radiographic features.

Bilateral simultaneous cavernous sinus sampling using corticotropin-releasing hormone in the evaluation of Cushing disease.

PURPOSE: To determine whether bilateral, simultaneous, cavernous sinus sampling after corticotropin-releasing hormone (CRH) stimulation offers as accurate detection and lateralization of Cushing disease as inferior petrosal sinus sampling does. METHODS: Seventeen consecutive patients with hypercortisolism and with high-dose dexamethasone suppression test results suggesting Cushing disease underwent bilateral cavenous sinus sampling with CRH stimulation. The diagnosis of Cushing disease was established in all patients by histologic examination or, if no tumor was found at surgery, by subtotal resection of the gland or radiation therapy resulting in eventual hypocortisolism or normal adrenal function and clinical remission. RESULTS: The sensitivity of cavenous sinus sampling with and without CRH in detecting Cushing disease was 94% and 71%, respectively. The abnormal side of the pituitary was correctly identified in all patients who had criteria for lateralization, yielding a positive predictive value of 100%. CONCLUSIONS: This small series suggests that cavernous sinus sampling with CRH is as accurate as inferior petrosal sinus sampling in detecting Cushing disease and perhaps more accurate in lateralizing the abnormality within the pituitary gland.

Intraarterial thrombolysis in vertebrobasilar occlusion.

PURPOSE: To report our experience using intraarterial thrombolysis in the treatment of vertebrobasilar occlusion. METHODS: Twelve patients with 13 angiographically proved thromboses of the vertebrobasilar system underwent local intraarterial thrombolysis with urokinase. Angiographic and clinical outcomes were analyzed with respect to clinical examination at presentation, arterial occlusion patterns, and time to recanalization. RESULTS: The overall mortality was 75%. Recanalization could not be achieved in 3 of 13 treatments; all patients in whom recanalization failed died. The mortality rate was 60% in those patients in whom recanalization was successful. Coma or quadriparesis at the time of therapy uniformly predicted death. There were two cases each of bilateral proximal vertebral occlusions and midbasilar occlusions and nine cases of bilateral distal vertebral occlusions. There were three cases of fatal rethrombosis after initial successful thrombolysis. The mortality rate in the recanalized group before rethrombosis was 30%. There were two fatal hemorrhages of the central nervous system. CONCLUSION: Recanalization of the vertebrobasilar system is necessary but not sufficient for effective treatment of vertebrobasilar occlusive disease. The site of occlusion may help predict angiographic and clinical outcome. Time to initiation of thrombolysis is not an invariable correlate of survival, although clinical condition at presentation may be. Rethrombosis and hemorrhage are significant problems affecting mortality after successful thrombolysis.

Assessing adequacy of collateral circulation during balloon test occlusion of the internal carotid artery with 99mTc-HMPAO SPECT.

A balloon test occlusion of the internal carotid artery was performed in 11 patients with internal carotid artery aneurysms. Tolerance by patients was assessed by a combination of clinical examination; angiography; electroencephalography; 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) single-photon emission computed tomography (SPECT) with relative quantification; and, in four patients, 99mTc-HMPAO SPECT with absolute quantification of cerebral blood flow. During test occlusion, angiography showed a patent circle of Willis in all patients. No patient developed new clinical findings or electroencephalographic changes. The SPECT studies of five patients in whom 99mTc-HMPAO was injected during test occlusion demonstrated changes from their baseline SPECT studies. The internal carotid artery was permanently occluded in two of these patients, neither of whom became symptomatic because of the occlusion. Three patients who demonstrated no changes between baseline and test occlusion SPECT studies underwent permanent occlusion of the internal carotid artery without incident, and postoperative SPECT images were unchanged from baseline. Our preliminary results suggest that patients who have no changes between baseline and test occlusion 99mTc-HMPAO SPECT studies should have adequate collateral circulation to sustain cerebral blood flow after occlusion of the internal carotid artery if no thromboembolic episodes occur. In contrast, a patient's tolerance of permanent occlusion cannot be consistently and reliably predicted if there are changes between baseline and test occlusion SPECT studies. In these patients, absolute quantitation of cerebral blood flow is important. Greater numbers of patients are required to confirm these initial results.

Reversibility of white matter changes and dementia after treatment of dural fistulas.

We describe two patients with dural fistulas who presented with dementia and diffuse white matter signal changes on MR that significantly improved after surgery. One patient had preoperative embolization.

Irreversible regional cerebral ischemia: serial MR imaging and proton MR spectroscopy in a nonhuman primate model.

PURPOSE: To delineate the changes in proton MR spectroscopy and imaging that occur with acute, irreversible ischemia of the basal ganglia of a baboon. MATERIALS AND METHODS: The M1 segments of the middle cerebral arteries of six adult male baboons were occluded by endovascular means with microcatheters and N-butyl cyanoacrylate adhesive. Cerebral blood flow measurements were taken with positron emission tomography or radioactive microsphere techniques. Serial spatially localized proton MR spectroscopy of the basal ganglia and MR imaging of the brain were performed. The distribution of ischemic and infarcted tissue was demonstrated by histopathologic techniques or triphenyltetrazolium chloride staining. RESULTS: Radioactive microsphere or positron emission tomography measurements demonstrated no significant cerebral blood flow within the basal ganglia after occlusion of the middle cerebral artery. Proton MR spectroscopy of the basal ganglia demonstrated increasing cerebral lactate and decreasing N-acetyl aspartate within 30 minutes of middle cerebral artery occlusion. Changes in the MR imaging signal intensity of the basal ganglia were observed as early as 3.1 hours on T2-weighted, 3.3 hours on T1-weighted, and 6.1 hours on spin density-weighted images. The distribution of these changes correlated well with the histopathologic features of ischemia and infarction that were seen throughout the basal ganglia. CONCLUSION: Changes in MR imaging signal intensity corresponded to ischemia and infarction in our baboon model of acute irreversible ischemia of the basal ganglia. Increasing cerebral lactate and decreasing N-acetyl aspartate preceded changes in MR imaging signal intensity.

Treatment of symptomatic cervical carotid dissections with endovascular stents.

OBJECTIVE: Symptomatic dissections of the cervical carotid artery (CCA) can be spontaneous or secondary to trauma and may be associated with pseudoaneurysms. Surgical treatment is often difficult or unavailable. We report the successful use of endovascular stents in the treatment of symptomatic dissection of the CCA. METHODS: Five consecutive patients with symptomatic CCA dissection were seen at our institution. There were four female patients and one male patient, ranging in age from 19 to 56 years. One dissection was spontaneous. The others were secondary to a gunshot wound (one patient), blunt neck trauma (two patients), and endovascular treatment of atherosclerotic carotid bifurcation disease (one patient). Balloon-expandable and self-expanding stents were placed via a transfemoral approach. RESULTS: Success in restoring the carotid lumen with two to five stents in each patient was angiographically demonstrated. There were no procedure-related complications. All patients experienced significant clinical improvement within the first 24 hours and complete long-term recovery. CONCLUSION: Symptomatic dissections of the CCA can be successfully treated by using endovascular stents.

Validation of transcranial Doppler ultrasound with a stereotactic neurosurgical technique.

Vessel identification during a transcranial Doppler (TCD) ultrasound examination is usually based on well-established inferential criteria without confirmation by imaging. Part of a routine study involves taking measurements from the M1 segment of the middle cerebral artery (MCA) and the A1 segment of the anterior cerebral artery (ACA) at the points of maximum mean linear blood flow velocity (LBFV). The authors tested the hypothesis that insonation is from the midpoints of the M1 and A1 segments during clinical TCD examinations. Conventional hand-held TCD examinations were performed on five volunteers. The points of maximum mean LBFV of the M1 and A1 segments of the MCA and ACA were located. Measurements were also taken from the midpoints of the M1 and A1 segments using a magnetic resonance (MR) imaging-guided stereotactic TCD technique. Values for depths of insonation and maximum mean LBFV obtained with the two techniques were compared. There was no significant difference between the two techniques for the measured values of depth of insonation of either the individual vessels (p > 0.11) or the aggregate (p = 0.46). There was a significant difference between the aggregate maximum mean LBFV measurements (p = 0.0022). The hand-held technique systematically produced higher maximum mean LBFV than the MR-guided stereotactic technique. The authors conclude that when using traditional criteria for TCD examination of the ACA and MCA, the points of insonation approximate the middle of the A1 and M1 segments.

Treatment of carotid-cavernous sinus fistulas using a superior ophthalmic vein approach.

The authors describe the method and results of treatment of 12 consecutive patients with carotid-cavernous sinus fistulas (CCFs). Treatment was by embolization via a transvenous approach through the superior ophthalmic vein (SOV). The CCFs (two direct and 10 dural) had previously been treated unsuccessfully or, for mechanical reasons, could not be treated by the standard techniques of endoarterial balloon occlusion, particle or glue embolization of feeding vessels from one or both external carotid arteries, or transvenous occlusion of the fistula via the ipsilateral inferior petrosal sinus. All 12 patients were successfully treated either by advancement of a detachable balloon catheter through the ipsilateral SOV into the cavernous sinus with subsequent inflation and detachment of the balloon (11 patients) or by introduction of multiple thrombogenic coils into the fistula via the ipsilateral SOV (one patient). All patients had complete resolution of symptoms and signs after successful occlusion of the CCF. There were no intraoperative complications; however, one patient required postoperative embolization of a residual posteriorly draining fistula via the ipsilateral external carotid artery, and another developed a persistent abducens nerve paresis that eventually required surgical correction. Ten (83.3%) of the 12 patients underwent cerebral angiography 3 to 6 months after surgery, and none showed evidence of a recurrent fistula. Similarly, none of the 12 patients developed recurrent symptoms and signs suggesting recurrence of the fistula during a follow-up period that ranged from 6 months to 10 years (mean 64 months). It is concluded that the transvenous approach to the cavernous sinus through the SOV is a safe and effective treatment of both direct and dural CCFs that are not amenable to transarterial or other transvenous approaches.

Relationships among the subjective quality, magnetic resonance spectra, and price of wine: a randomized trial.

RATIONALE AND OBJECTIVES: We sought to discriminate among wines on the basis of three techniques: physical properties such as smell, taste, and quality; market price; and chemical analysis using proton nuclear magnetic resonance (MR) spectroscopy. METHODS: A randomized, double-masked, controlled crossover wine-tasting trial was conducted. Participants included seven men and seven women affiliated with an urban academic medical center, half of whom were physicians. The interventions consisted of eight red and eight white wines, including two respective, lower priced control wines. Each subject sampled all wines. Participants rated the overall quality of wine samples on a 5-point scale. The outcome measures were mean wine quality score, market price, and visual analysis of proton nuclear MR spectra. RESULTS: One subject dropped out. Three white wines (ps = .0245, .0275, and .0425) and two red wines (ps = .0072 and .0128) were rated significantly higher than their respective, lower priced control wines. The mean wine quality score was not significantly correlated with market price (white wine, rho = .371, p = .326; red wine, rho = -.072, p = .8492). Visual analysis of proton nuclear MR spectra from the highest scoring wines and their respective control wines revealed more similarities than differences. CONCLUSION: Quality assurance of wine may best be left to the discriminating palate rather than market price or visual analysis of proton nuclear MR spectra.

Radionuclide imaging of a rectus sheath hematoma caused by insulin injections.

CT scanning, MRI, and ultrasonography are the imaging procedures of choice for the study of rectus sheath hematomas. A rectus sheath hematoma was evaluated scintigraphically after the intravenous administration of Tc-99m labeled RBC, which confirmed the hematoma, demonstrated the sites of bleeding, and revealed continued bleeding.

Failure of technetium-99m sulfur colloid uptake by the femoral head. Aseptic necrosis or normal variation?

The hips of 79 asymptomatic patients having Tc-99m sulfur colloid liver/spleen scans were imaged. Patients were not studied if they had a disease associated with nonvisualization of the femoral heads. The first group consisted of 47 consecutive patients who were imaged in a neutral position. Eighteen right and 18 (38.3%) left hips showed no activity. The second group consisted of 32 consecutive patients who were imaged in an internally rotated position. Seven (21.9%) right and nine (28.1%) left hips showed no activity. This study concludes that failure of uptake of Tc-99m sulfur colloid by the femoral head is seen in a sufficiently large group of patients to limit its use in diagnosing aseptic necrosis.