Although conventional proton magnetic resonance imaging has increased our ability to detect brain tumors, it has not enhanced to nearly the same degree our ability to diagnose tumor type. Proton magnetic resonance spectroscopy is a safe, noninvasive means of performing biochemical analysis in vivo. Using this technique, we characterized and classified tissue from normal brains, as well as tissue from the five most common types of adult supratentorial brain tumors. These six tissue types differed in their pattern across the six metabolites measured. 'Leaving-one-out' linear discriminant analyses based on these resonance profiles correctly classified 104 of 105 spectra, and, whereas conventional preoperative clinical diagnosis misclassified 20 of 91 tumors, the linear discriminant analysis approach missed only 1. Thus, we have found that a pattern-recognition analysis of the biochemical information obtained from proton magnetic resonance spectroscopy can enable accurate, noninvasive diagnosis of the most prevalent types of supratentorial brain tumors.

Summary: 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 main tained until the end of the second PET studies. CBF, cerebral blood volume (CBV), oxygen extraction ratio (OER), CMR02, and CMRglc were measured each time. These metabolic and perfusion measurements were per formed by standard methods. A surface map of each met abolic and perfusion measurement in the cortical mantle was generated by interpolating between the available slices. The various surface maps representing the physi ological characteristics determined in the same or subse quent 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 cerebrovascu- 523 lar 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/loo g/min on the first PET scan, while densely isch emic regions had CBF of <12 nlllOO glmin and normally perfused brain> 18 ml/loo 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 CMR02 noted in the carrier group, the difference in the changes being signif icant. In the penumbra zone, comparable trends were noted in OER and CMR02 but the difference in the changes between the two groups did not reach statistical significance. Changes in CMRglc and CBV were compa rable between the two groups in both cortical regions.

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IntroductionWhile numerous studies have documented evidence for plasticity of the human brain there is little evidence that the human spinal cord can change after injury. Here, we employ a novel spinal fMRI design where we stimulate normal and abnormal sensory dermatomes in persons with traumatic spinal cord injury and perform a connectivity analysis to understand how spinal networks process information.MethodsSpinal fMRI data was collected at 3 Tesla at two institutions from 38 individuals using the standard SEEP functional MR imaging techniques. Thermal stimulation was applied to four dermatomes in an interleaved timing pattern during each fMRI acquisition. SCI patients were stimulated in dermatomes both above (normal sensation) and below the level of their injury. Sub-group analysis was performed on healthy controls (n = 20), complete SCI (n = 3), incomplete SCI (n = 9) and SCI patients who recovered full function (n = 6).ResultsPatients with chronic incomplete SCI, when stimulated in a dermatome of normal sensation, showed an increased number of active voxels relative to controls (p = 0.025). There was an inverse relationship between the degree of sensory impairment and the number of active voxels in the region of the spinal cord corresponding to that dermatome of abnormal sensation (R2 = 0.93, p<0.001). Lastly, a connectivity analysis demonstrated a significantly increased number of intraspinal connections in incomplete SCI patients relative to controls suggesting altered processing of afferent sensory signals.ConclusionsIn this work we demonstrate the use of spinal fMRI to investigate changes in spinal processing of somatosensory information in the human spinal cord. We provide evidence for plasticity of the human spinal cord after traumatic injury based on an increase in the average number of active voxels in dermatomes of normal sensation in chronic SCI patients and an increased number of intraspinal connections in incomplete SCI patients relative to healthy controls.

Twelve patients were studied within 48 hours of stroke using positron emission tomography to determine cerebral blood flow (CBF), cerebral metabolic rate for oxygen (CMRO2), oxygen extraction fraction, cerebral blood volume, cerebral pH (CpH), and cerebral metabolic rate for glucose (CMRGlc), the last calculated using published normal rate constants (CMRGlc[N]) and those for severe ischemia. In these studies, a cortical region of severe ischemia (I) was outlined, its metabolic and perfusion properties evaluated, and its length measured. The contralateral uninvolved cortical rim (C) in these patients and the cortical rim in 5 older normal patients were used for comparison. The length of region I correlated with the neurological deficit measured independently by a clinical scoring method. The 12 patients fell into two groups: Group I (8 patients), whose CBF in I was 9.3 +/- 2.5 ml/100 gm/min (mean +/- SEM) and was in every patient lower than that in C (33.1 +/- 2.2), and Group 2 (4 patients), whose CBF in I was 42.1 +/- 8.5 ml/100 gm/min and was in every case higher than that in C (28.2 +/- 1.5). In Group I, region I showed a CMRGlc(N)/CMRO2 ratio of 0.22 +/- 0.06 and a CpH of 6.83 +/- 0.06. In Group 2, the same ratio in the region I was 0.58 +/- 0.09 and the CpH was 7.12 +/- 0.05. The CMRGlc (N)/CMRO2 ratio for the contralateral hemisphere was comparable in the two groups. Our data suggest that, within 48 hours of the clinical onset of stroke, the ischemic cortex is already reperfused in one third of patients. Those ischemic regions with persistent hypoperfusion appear acidotic, whereas in the reperfused regions, despite evidence of an increased CMRGlc/CMRO2 ratio, acidosis is not evident. The implications of these findings for therapies proposed in acute human cerebral ischemia are discussed.

Our results suggest that appropriate analysis of (1)H-MRSI data can predict survival in patients with supratentorial gliomas at least as accurately as data derived from more invasive clinicopathological features.

Spinal angiolipomas are distinct, benign lesions composed of mature lipocytes admixed with abnormal blood vessels. Three new cases of spinal angiolipoma are presented and 34 previously reported cases are analyzed. The 37 total cases (23 females and 14 males) ranged in age from 17 to 73 years (mean 43 years; median 45 years). The mean age of the female patients was older than that for the males (45.0 vs. 41.6 years; p < 0.001, Student's t-test) and most were peri- or postmenopausal. Prior to diagnosis, 97% of the patients had weakness of the lower extremities, 94% had sensory dysfunction, 84% had hyperreflexia and spasticity, 51% had sphincter dysfunction, and 41% had back pain lasting from 1 to 180 months (mean 28 months). Five (22%) of the 23 female patients were pregnant and two had exhibited significant weight gain coincident with the onset of symptoms. The angiolipomas were extradural in 35 patients and intramedullary in two; seven of the extradural lesions infiltrated the surrounding bone. The tumors extended from C-6 to L-4 and had a predilection for the midthoracic region (53% of cases). Plain radiographs were abnormal in 11 (39%) of 28 patients and in all patients with bone infiltration. Myelograms were abnormal in 97% of 32 patients and showed a complete block in 63% of patients. Computerized tomography (CT) and magnetic resonance (MR) imaging revealed the fat-density lesions in all cases studied. There was vascular enhancement in three of five cases with contrast-infused CT and in the one case with gadolinium-infused MR imaging. All patients improved following resection of the epidural lesions and internal decompression of the intramedullary lesions. It is concluded that spinal angiolipomas predominantly affect women. They involve the thoracic (especially the midthoracic) region, and produce symptoms and signs of spinal compression and, in some cases, bone erosion and pathological fractures. Their symptomatology can be exacerbated by pregnancy and weight gain, suggesting that vascular engorgement and the presence of obesity influence their evolution. Their preponderance in older, peri-, or postmenopausal women, and their clinical exacerbation in pregnant women support a role for hormonal influence. Magnetic resonance imaging is the investigation of choice for the diagnosis of these lesions. Surgery is universally successful in relieving symptoms.

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 Alzheimer's 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)