Ronald Pokrupa

The Effect of Nimodipine on the Evolution of Human Cerebral Infarction Studied by PET

Fourteen patients were studied by positron emission tomography (PET) within 48 h of onset of a hemispheric ischemic stroke and again 7 days later. After the first set of PET scans, the patients were randomized to receive either nimodipine (n = 7) or a carrier solution (n = 7) by intravenous infusion. The infusions were maintained until the end of the second PET studies. CBF, cerebral blood volume (CBV), oxygen extraction ratio (OER), CMRO2, and CMRglc were measured each time. These metabolic and perfusion measurements were performed by standard methods. A surface map of each metabolic and perfusion measurement in the cortical mantle was generated by interpolating between the available slices. The various surface maps representing the physiological characteristics determined in the same or subsequent studies were aligned so that all data sets could be analyzed identically using an array of square regions of interest (ROIs). The functional status of each ROI was recorded at the two intervals following the cerebrovascular accident to characterize the evolution of the infarct, penumbra, and normal brain regions. We presumed the ischemic penumbra to be cortical regions in the proximity of the infarct and perfused at CBF values between 12 and 18 ml/100 g/min on the first PET scan, while densely ischemic regions had CBF of <12 nl/100 g/min and normally perfused brain >18 ml/100 g/min. In the densely ischemic zone, CBF increased more in the nimodipine-treated group than in the carrier group. As well, in this region nimodipine reversed the decline in CMRO2 noted in the carrier group, the difference in the changes being significant. In the penumbra zone, comparable trends were noted in OER and CMRO2 but the difference in the changes between the two groups did not reach statistical significance. Changes in CMRglc and CBV were comparable between the two groups in both cortical regions.

Three-dimensional Computed Tomographic Angiography of Cerebral Aneurysms

We describe our technique and results of dynamic, reconstructed, three-dimensional (3-D) computed tomographic (CT) angiography in our first 18 patients with either complex aneurysms, producing subarachnoid hemorrhage or the compression of neighboring structures, or small asymptomatic aneurysms, and assess the role of this technique in treatment planning. A dynamic, infused CT scan producing 1.5-mm cuts of the area of interest was performed, and the two-dimensional images were reconstructed in three dimensions with the ISG Allegro system (ISG Technologies, Toronto, Ontario, Canada). Results were compared with intra-arterial digital subtraction angiography and magnetic resonance angiography. All aneurysms over 3 mm and half of the aneurysms less than or equal to 3 mm were demonstrated by 3-D CT angiography. The neck of the aneurysm, its relationship to the parent artery and associated branches, and its relationship to surrounding bony structures, such as the anterior clinoid, were also demonstrated. This was especially useful for ophthalmic aneurysms. The 3-D image could be rotated on the screen to mimic the operative approach. The active, filling portion and the thrombosed part of partially thrombosed, giant aneurysms could be seen on the same image, and the active, filling portion could be better appreciated with 3-D CT angiography than with magnetic resonance angiography. A partially treated, acrylic-coated aneurysm that could not be completely assessed otherwise has been demonstrated by this technique. 3-D CT angiography is useful in the evaluation of aneurysms, especially when the local anatomy is obscured or distorted by its mass or by the anterior clinoid.(ABSTRACT TRUNCATED AT 250 WORDS)

Proton magnetic resonance spectroscopic imaging can predict length of survival in patients with supratentorial gliomas.

OBJECTIVEWe compared the ability of proton magnetic resonance spectroscopic imaging (1H-MRSI) measures with that of standard clinicopathological measures to predict length of survival in patients with supratentorial gliomas. METHODSWe developed two sets of leave-one-out logistic regression models based on either 1) intratumoral 1H-MRSI features, including maximum values of a) choline and b) lactate-lipid, c) number of 1H-MRSI voxels with low N-acetyl group values, and d) number of 1H-MRSI voxels with high lactate-lipid values, all (a–d) of which were normalized to creatine in normal-appearing brain, or 2) standard clinicopathological features, including a) tumor histopathological grade, b) patient age, c) performance of surgical debulking, and d) tumor diagnosis (i.e., oligodendroglioma, astrocytoma). We assessed the accuracy of these two models in predicting patient survival for 6, 12, 24, and 48 months by performing receiver operating characteristic curve analysis. Cox proportional hazards analysis was performed to assess the extent to which patient survival could be explained by the above predictors. We then performed a series of leave-one-out linear multiple regression analyses to determine how well patient survival could be predicted in a continuous fashion. RESULTSThe results of using the models based on 1H-MRSI and clinicopathological features were equally good, accounting for 81 and 64% of the variability (r2) in patients’ actual survival durations. All features except number of 1H-MRSI voxels with lactate-lipid/creatine values of at least 1 were significant predictors of survival in the 1H-MRSI model. Two features (tumor grade and debulking) were found to be significant predictors in the clinicopathological model. Survival as a continuous variable was predicted accurately on the basis of the 1H-MRSI data (r = 0.77, P < 0.001; median prediction error, 1.7 mo). CONCLUSIONOur results suggest that appropriate analysis of 1H-MRSI data can predict survival in patients with supratentorial gliomas at least as accurately as data derived from more invasive clinicopathological features.

Diagnosis and treatment of ossification of the posterior longitudinal ligament of the spine : report of eight cases and literature review

PURPOSE Ossification of the posterior longitudinal ligament (OPLL) is a common, well-recognized cause of spinal stenosis and myelopathy in Japan. Although also common in whites, especially among the elderly, it has received little scientific attention. We wish to increase awareness of this important cause of myelopathy, and to determine if the clinical characteristics of OPLL are similar in non-Japanese and Japanese patients. PATIENTS AND METHODS The clinical and radiologic features of eight cases of OPLL are presented. These cases combined with 73 non-Japanese cases gathered from the English literature are contrasted with 2,125 Japanese cases of OPLL. RESULTS Similarities among non-Japanese and Japanese cases included: (1) male predominance; (2) peak age at onset of symptoms in the sixth decade; (3) clinical presentation, which ranged from asymptomatic to quadriplegia, with progressive or acute onset of neurologic deterioration; (4) greater than 95% localization to the cervical spine, spastic quadriparesis being the most common neurologic presentation; (5) an association with several rheumatic conditions including diffuse idiopathic skeletal hyperostosis (DISH), spondylosis, and ankylosing spondylitis; and (6) neurologic improvement with either conservative or surgical treatment in a significant proportion of patients. Differences between the two groups were minimal and included a higher mean age at onset (although onset in both groups occurred within the sixth decade) and a greater proportion of patients with DISH and with the continuous type of OPLL in the non-Japanese group. CONCLUSION The clinical characteristics of OPLL are similar in Japanese and non-Japanese patient populations. Increased awareness of this condition, which has potentially devastating neurologic complications, will favorably influence diagnosis, treatment, and outcome.

Spontaneous dissecting aneurysm of the extracranial vertebral artery.

Spontaneous dissection of a cervical vertebral artery secondary to fibromuscular hyperplasia is uncommon, is often painful, and may be followed after a latent interval by further symptoms of embolism, occlusion, or hemorrhage. Accordingly, the lesion is potentially hazardous and warrants treatment when recognized.

Surgical Considerations in Cerebral Amyloid Angiopathy

In cerebral amyloid angiopathy, the contractile elements of the leptomeningeal and cortical arteries are replaced by noncontractile amyloid beta protein. The incidence of amyloid angiopathy increases with advancing age. It is associated with Alzheimers disease and spontaneous cerebral hemorrhage. The latter can have the characteristic acute computed tomographic appearance of a hematoma at the cortex-white matter junction with extension of blood into the subarachnoid, subdural, and intraventricular spaces. Multiple hemorrhages are frequent. Additional bleeding can occur after evacuation of the hematoma, and postoperative hemorrhage can occur after cortical biopsy. To elucidate the role of surgery in this condition, we have reviewed 20 consecutive operated cases of cerebral amyloid angiopathy. A first group of 8 patients with senila dementia underwent cortical biopsy without resultant hemorrhage. A second group of 6 patients in good clinical condition had delayed evacuation of a spontaneous cerebral hematoma from cerebral amyloid angiopathy because of the radiological misdiagnosis of a hemorrhage within a tumor. One patient died of a pulmonary embolism, and another had subsequent multiple hemorrhages that were ultimately fatal. A third group of 6 patients in poor neurological condition had the acute evacuation of a spontaneous cerebral hematoma to relieve intracranial hypertension. All died or were severely disabled. One had repeated hemorrhages which added a progressively more severe organic dementia onto an initial hemiplegia.(ABSTRACT TRUNCATED AT 250 WORDS)

Glioependymal cysts : CT and MR findings

Four patients with intracranial glioependymal cysts were evaluated in our institution in the last 7 years. All underwent surgical drainage and biopsy of the cyst wall. Cranial CT revealed a uniformly hypodense lesion with no contrast enhancement in all cases. Magnetic resonance imaging studies revealed a well defined cyst that was isointense to CSF on T1-weighted images and iso- or mildly hyperintense to CSF on proton density and T2-weighted images. In one case, a fluid-fluid level was demonstrated within the cavity, indicating the presence of fluid with a high protein content. A diagnosis of glioependymal cysts can be suggested based on CSF-like intensity patterns on T1-weighted images and iso- or mild hyperintensity on T2-weighted images.

Conservative therapy of atlantoaxial osteomyelitis: A case report

Study Design A rare case of C1‐C2 vertebral osteomyelitis treated conservatively is described. The radiologic findings as well as the follow‐up evaluation are reported. Objective To increase knowledge about the pathogenesis and treatment of vertebral osteomyelitis in the high cervical region. Summary of Background Data This is one of the first cases reported of successful conservative treatment of osteomyelitis at this level. Methods In a 58‐year‐old man with lumbar staphylococcal infection, a subsequent cervical infection developed. Because the lumbar spondylitis was treated promptly, the cervical osteomyelitis was treated at a very early stage of development. Results Operative decompression is the treatment most often used in osteomyelitis at the C1‐C2 level. This is an extremely unusual circumstance in which early treatment of the infection negated the need for surgery. Conclusion Conservative treatment of osteomyelitis at the C1‐C2 level can be efficacious in the correct setting.

Primary ectopic meningioma of the neck: MR features.

Although meningiomas represent 15% of the tumors of the CNS, primary ectopic meningioma is a very rare finding. Four mechanisms for the formation of ectopic meningioma have been suggested: (a) direct extension of an intracranial lesion; (b) distant metastasis from an intracranial meningioma; (c) origin from arachnoid cells within the sheaths of cranial nerves; and (d) origin from embryonic nests of arachnoid cells. The case we present underwent a complete neuroradiological screening, and, although the neuroradiological findings were nonspecific to provide a correct diagnosis, they were useful for assessment of the tumor extension and for surgical planning. Particularly, magnetic resonance gave a panoramic view of the tumor and suggested its extensive vascularization, which was confirmed later by angiography.

Subacute enlarging cerebral hematoma from amyloid angiopathy: case report.

We report the case of a 74-year-old woman who, during a 36-hour period, developed progressive, focal neurological deficits and eventual coma associated with a spontaneously enlarging intraparenchymal hematoma resulting from cerebral amyloid angiopathy. The subacute, progressive enlargement of the hematoma, confirmed by serial computed tomographic scans, supports the hypothesis that hematomas enlarge in amyloid angiopathy as a result of the replacement of the contractile elements of the arterial wall by noncontractile amyloid protein. This interference with vasoconstriction, the first phase of hemostasis, may be supplemented by local endothelial dysfunction causing alterations in the chemical mediators of hemostasis, thereby promoting hemorrhage and hematoma enlargement.