MR and CT evaluation of intracranial sarcoidosis

Fourteen patients with CNS manifestations of neurosarcoidosis were evaluated by MR imaging and CT. Evaluations were done on a 0.5-T superconductive magnet with T1- and T2-weighted sequences. CT with contrast was obtained in all patients. The granulomatous lesions were classified by location into basilar, convexity, intrahemispheric, and periventricular white-matter involvement. Hydrocephalus with or without an associated lesion was also noted. MR determined the presence of disease in all patients (100%), but was less accurate than CT in depicting disease in two patients (14%). CT determined the presence of disease in 12 patients (85%) and was less accurate than MR in delineating hypothalamic involvement in two patients and periventricular white-matter disease in three patients. There was great variability in the appearance of intracranial sarcoidosis on MR. Three patients had lesions that were isointense or hypointense (relative to cerebral cortex) on both T1- and T2-weighted images while nine patients had lesions that were hyperintense on T2-weighted images. Convexity involvement and hydrocephalus were well documented by both CT and MR. These results indicate that both MR and CT are helpful in fully evaluating a patient with suspected intracranial sarcoidosis.     

Head trauma: comparison of MR and CT--experience in 100 patients

The results of CT and MR imaging were reviewed retrospectively and compared in 100 patients who experienced clinically significant head trauma. The findings were analyzed on the basis of several parameters in an attempt to establish objective clinical guidelines for the use of each diagnostic technique. CT remains the screening method of choice in evaluating acute severe head trauma; however, MR revealed additional clinically relevant findings in all four cases in which the patient's clinical symptoms were disproportionate to the CT findings. MR was equal or superior to CT in the evaluation of all patients with acute minor head trauma and in 94 of 95 patients examined in the subacute, chronic, or remote phase of injury, irrespective of the severity or pathologic nature of their injuries. All subacute contusions (21 lesions) and white-matter shearing lesions (18 cases) were demonstrated to particular advantage on MR compared with CT, as were all subdural hematomas (of 52 small subdural collections, 58% were detected only by MR). Although surgical management was not altered by the additional information provided by MR, the implications regarding the medical management and disposition of the patients with head trauma were significant.     

Leukoencephalopathy in normal and pathologic aging: 1. CT of brain lucencies

Central white matter lucencies are commonly seen in CT scans of elderly patients. Reports in the literature have implicated demyelination due to subcortical vascular disease (Binswanger disease) as the cause of these lucencies. Binswanger disease, however, is thought to be rare. Because of this apparent discrepancy we decided to determine the incidence and to attempt to define the clinical significance of the CT white-matter changes in a study population at New York University Medical Center. The studies of 275 normal and demented subjects, ages 23 to 85 years, were reviewed. All subjects received neurologic, psychiatric, and medical evaluation, formal psychometric evaluation of their cognitive status, and a CT scan. CT scans were evaluated for the presence and severity of white-matter changes (leukoencephalopathy). The incidence and severity of white-matter changes increased significantly with age (p less than 0.01). Leukoencephalopathy was consistently more common in demented patients than in normal subjects, but the difference was not statistically significant, and the severity of the leukoencephalopathy was not related to the severity of dementia (p less than 0.05). Five patients (ages 74 to 95 years) with a clinical diagnosis of Alzheimer disease who had CT evidence of lucencies were examined at autopsy. Neuropathology demonstrated extensive changes of Alzheimer disease in one brain and mild-to-moderate changes in the other four brains; areas of white-matter rarefaction were present in all brains, with microscopic evidence of arteriolar hyalinization. This study demonstrates that leukoencephalopathy is strongly related to the aging process and is seen in both "normal" and cognitively impaired individuals who have no other evidence of vascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)     

Subacute sclerosing panencephalitis: evaluation with CT and MR.

PURPOSETo evaluate the progression of CT and MR changes of the brain in subacute sclerosing panencephalitis (SSPE) as a basis for assessing the effects of different types of therapy.METHODSFifty-two patients with SSPE were examined, 44 with MR imaging and 42 with CT of the brain on one or more occasions. A total of 92 MR and 67 CT studies were performed.RESULTSCorrelation between the clinical status and the MR findings in admission was poor. Of 20 patients with clinically advanced disease, only 8 had marked MR abnormalities; 6 had normal or almost normal findings on MR examinations. Two of 4 patients with clinically mild disease had advanced MR changes. The progression of the MR findings appeared to follow a constant pattern. The earliest pathologic finding was focal, high-T2-intensity white matter changes; later atrophic changes followed. The atrophy lagged behind the white matter changes and was thus mild when white matter changes were moderate or severe. In the most advanced stage, when the patient was in a neurovegetative state, an almost total loss of white matter had usually taken place. At this stage, the corpus callosum was also thin. Basal ganglia changes, usually involving the putamina, were seen in one third of patients and cortical gray matter changes were seen in one fourth of patients examined with MR imaging. In 2 of 20 patients, MR changes regressed in parallel with clinical improvement following therapy, but in 5 patients clinical improvement was accompanied by progression of MR changes.CONCLUSIONThe progress of MR abnormalities seen in patients with SSPE seems to follow a constant pattern, but the severity of MR changes does not always correlate well with the clinical findings. Caution must therefore be used when evaluating the effects of therapy.     

Wilson disease of the brain: MR imaging

Twenty-three patients with biochemically proved Wilson disease underwent magnetic resonance (MR) imaging of the brain. Positive findings, believed secondary to this condition, were found in 15 subjects. Findings varied among patients, but there were striking similarities between certain groups of patients. Areas of abnormal signal were seen in the lenticular, thalamic, caudate, and dentate nuclei, as well as in the brain stem; in these areas, the abnormalities were bilaterally symmetric. A smaller number of patients had asymmetric focal white-matter lesions. Correlation of the MR findings with clinical symptoms was generally good. Repeat imaging was performed on five patients at intervals ranging from 4 to 8 months; none showed significant interval change.     

Central nervous system disease in acquired immunodeficiency syndrome: prospective correlation using CT, MR imaging, and pathologic studies

A prospective study compared the abilities of high-resolution computed tomography (HRCT) and magnetic resonance (MR) imaging in detection and evaluation of central nervous system disease in neurologically symptomatic patients with acquired immunodeficiency syndrome (AIDS). Eighteen CT scans and 19 MR images in 14 patients were compared. HRCT images with contrast material enhancement were superior to unenhanced 0.35-T MR images for differentiating a lesion from surrounding edema, discriminating between lesions in close proximity, locating lesions for biopsy, judging lesion activity, detecting small cortical lesions with minimal edema, and spatial resolution. MR imaging was superior to CT scanning in evaluation of white-matter lesions and detection of small lesions surrounded by edema. MR imaging exhibited higher contrast resolution and greater sensitivity. Complementary uses of MR and CT imaging are suggested.     

Central nervous system changes after radiation therapy and/or chemotherapy: correlation of CT and autopsy findings

This is a restrospective correlative study of cranial computed tomography (CT) and autopsy findings in 50 patients after central nervous system radiation therapy and/or chemotherapy. Most patients had more than one posttherapy CT scan and all cases were autopsied. Twenty-six cases (52%) showed no posttherapy CT changes. In 18 cases (36%) enlargement of intracranial subarachnoid spaces and/or ventricles was seen on CT, but only two of these cases showed gross atrophy on postmortem examination; even in these, the cortex was histologically normal, suggesting that these CT changes may be reversible. In six cases a decrease in white-matter density was seen on CT. Two of these cases were histologically normal, two cases showed some white-matter rarefaction, one case contained multiple foci of white-matter and vessel well necrosis, and one case had progressive multifocal leukoencephalopathy.     

Radiation effects on cerebral white matter: MR evaluation

The purpose of this study was to evaluate the white-matter changes associated with cranial radiation by MR imaging. The MR scans of 95 patients receiving conventional external beam radiation for a wide variety of central nervous system tumors were reviewed. Moderately T2-weighted spin-echo images with a 2000-msec repetition time and 56-msec-echo time were analyzed for white-matter abnormalities without knowledge of the patient's history. These were correlated with radiation dose, port, and time interval since completion of therapy, and then compared with an age-matched control group of 180 patients with nonirradiated, space-occupying, intracranial lesions. Radiation-related lesions were characterized as symmetric, high-signal foci in the periventricular white matter. Relative sparing of the posterior fossa, basal ganglia, and internal capsules was noted. In patients older than 20 years, these changes paralleled those seen in ischemia but were more prevalent (p less than .005). In 25 patients with sequential MR scans, these findings remained stable. In those patients with limited treatment fields, for example, pituitary adenomas, no statistical differences were seen between radiation-treated and nontreated groups. Cerebral white-matter changes that mimic deep white-matter infarction are frequently seen in response to therapeutic radiation. There is a variable incidence of radiation effects, becoming more marked in older patients. MR interpretation must consider the neuropathologic consequences of therapeutic radiation, which include demyelination, microvascular occlusion, and blood-brain barrier breakdown.     

MR of brain involvement in progressive facial hemiatrophy (Romberg disease): reconsideration of a syndrome.

PURPOSETo gain further insight into the pathogenesis of progressive facial hemiatrophy, a sporadic disease of unclear etiology characterized by shrinking and deformation of one side of the face.METHODSWe investigated possible brain involvement. MR of the head and face was performed in three female patients with progressive facial hemiatrophy. The central-nervous-system findings were correlated to a clinical protocol and a review of the literature.RESULTSOne patient with epilepsy had abnormal brain findings confined to the cerebral hemisphere homolateral to the facial hemiatrophy. These consisted of monoventricular enlargement, meningocortical dysmorphia, and white-matter changes.CONCLUSIONSThese MR findings, and corresponding neuroradiologic data disclosed by the review, indicate that homolateral hemiatrophy occasionally occurs in a subgroup of patients with progressive facial hemiatrophy. The MR features do not seem consistent with an underlying simple or nutritive atrophic process. We propose chronic localized meningoencephalitis with vascular involvement as a possible underlying cause of the occasional brain involvement in progressive facial hemiatrophy.     

CT findings in a case of deficiency of 3-hydroxy-3-methylglutaryl-CoA-lyase

Summary Two CT scans have been performed on a child with a biochemically confirmed 3-HMG-CoA-lyase deficiency. Macrocephalus, widespread hypodensity of the white matter with cystic alterations and progressive dilatation of the ventricles were found. The clinical features and CT findings are surprisingly similar to findings in patients with spongy degeneration (Canavan).     

Human brain infarcts: Gd-DTPA-enhanced MR imaging

During Food and Drug Administration phase II and III clinical trials for gadolinium DTPA, the paramagnetic agent was used to study 11 patients with 20 subacute and chronic cerebral infarcts. Five patients had numerous periventricular and deep white-matter lesions, probably due to chronic ischemic disease. Magnetic resonance (MR) imaging was performed 4-30 days after the ictus, preceded by computed tomography (CT) in all but one case. In most cases, the nonenhanced spin-echo (SE) images, obtained at 500-msec repetition times and 30-msec echo times, failed to demonstrate the infarct, and in general the gadolinium-enhanced SE 500/30 images matched the contrast material-enhanced CT scans in pattern. Periventricular lesions and small, deep, white-matter infarcts that were chronic and asymptomatic were not enhanced by gadolinium MR. However, three small, symptomatic capsular and brain-stem infarcts showed definite enhancement. Usually the enhancement was visible at 3 minutes, increasing to a peak at 30 minutes. At 55 minutes, the enhancement increased in the medium-aged infarcts (8-14 days), while it decreased in the late infarcts (15-30 days). The T2 relaxation time-weighted pulse sequences were most sensitive for demonstrating all infarcts, but without the aid of a contrast agent, they were frequently poor in specificity.     

Imaging studies in a unique familial dysmyelinating disorder.

We report the imaging findings in five patients with a unique dysmyelinating disorder. MR studies of these infants showed obstructive hydrocephalus caused by mass effect produced by an enlarged cerebellum. The white matter of an enlarged cerebrum and cerebellum showed delayed myelination. Proton spectroscopy showed normal N-acetylaspartate (NAA) levels. While the dysmyelinating disorder was clearly differentiated from Canavan disease by an absence of elevated NAA and differing histopathologic findings and autosomal-dominant inheritance pattern, there were similarities to this disease in the presentation and, to some extent, in the initial imaging findings.     

Deceptively normal MR in early infantile Krabbe disease.

The authors present two cases of 5-month-old children with early infantile Krabbe disease studied by CT and MR. Both infants had characteristic CT scans for the disease consisting of symmetric hyperdensity involving the cerebellum, thalami, caudate, corona radiata, and brain stem. One of the infants had a deceptively normal initial MR examination, with dramatic progression of the white-matter disease over the following 4 months.     

Metabolic and destructive brain disorders in children: findings with localized proton MR spectroscopy

The diagnostic potential of volume-selective proton magnetic resonance (MR) spectroscopy in vivo was evaluated in 20 children and young adults with various neurodegenerative brain disorders. All patients were examined with MR spectroscopy in conjunction with MR imaging of the brain on a whole-body imager at 1.5 T. Comparison of spectra in our patients with those of children with normal myelination (prominent signals from N-acetylaspartate [NAA], creatine/phosphocreatine, and choline) revealed a marked decrease of NAA in 12 of 17 patients with focal or generalized demyelination. In patients with Canavan disease, NAA signal intensity was markedly increased, but no choline signal was found. Increased signal intensity from lactate occurred in patients with Leigh disease, neuroaxonal dystrophy, Schilder disease, and Cockayne disease, which indicated a disturbed energy metabolism in the examined region. These results demonstrate that proton MR spectroscopy can be applied in a clinical environment to facilitate diagnosis of hereditary and acquired brain disorders in children.     

Leukoaraiosis: correlation of MR and CT findings with blood flow, atrophy, and cognition

Hypodense periventricular white-matter lesions detected by CT (leukoaraiosis) and high-intensity T2 signals detected by MR imaging were correlated with measurements of local cerebral blood flow (LCBF), cerebral atrophy, and cognitive performance. Subjects studied included elderly volunteers who were neurologically normal (n = 6), patients with chronic cerebral infarctions and intact cognition (n = 2), patients with multiinfarct dementia (n = 14), and patients with Alzheimer dementia (n = 9). Leukoaraiosis correlated with periventricular high-intensity lesions detected by MR, LCBF reductions, cognitive impairments, and cerebral atrophy. Moderate to severe leukoaraiosis was associated with LCBF reductions in the cortex, basal ganglia, and frontal white matter. Periventricular MR lesions correlated with cerebral atrophy but not with cognitive impairments or reductions in LCBF. The exquisite sensitivity of MR revealed small lesions that did not correlate with LCBF reductions and cognitive impairments. Remote subcortical white-matter lesions detected by MR did not correlate with periventricular MR lesions, leukoaraiosis, LCBF, cerebral atrophy, or cognitive performance, indicating little clinical relevance. We concluded that diffuse cerebral hypoperfusion, particularly in combination with the poor collateral circulation of white matter surrounding the lateral ventricles, is responsible for leukoaraiosis.     

MR of Leigh's disease (subacute necrotizing encephalomyelopathy)

MR images of three patients with Leigh's disease (subacute necrotizing encephalomyelopathy) were compared with CT findings. In all patients typical lesions in the basal ganglia were identified with both MR and CT. In two patients MR permitted identification of additional lesions not detected with CT. In one patient progression of MR abnormalities over a 4-month period correlated well with clinical deterioration in neurologic status. T2-weighted images with a repetition time (TR) greater than 1950 msec and an echo time (TE) greater than or equal to 60 msec or inversion-recovery images with a 50-msec TE, 1213-msec inversion time, and 3000-msec TR were advantageous in identifying multiple necrotic lesions in the brainstem, deep gray matter, periventricular white matter, and cerebral cortex. In this series MR was more sensitive in detecting and localizing multifocal necrotic lesions of Leigh's disease than CT was, and thus may be a useful diagnostic tool for patients with the appropriate clinical and laboratory abnormalities.     

Lumbar herniated disk disease and canal stenosis: prospective evaluation by surface coil MR, CT, and myelography

Sixty patients with suspected lumbar herniated disk and/or canal stenosis were studied prospectively with surface coil MRI, CT, and/or myelography, and the results were compared with the surgically confirmed abnormality. Forty-eight patients had lumbar surgery at 62 levels. There were no negative explorations. Thirty-nine patients had a myelogram and CT. Thirty of the CTs were performed following the injection of metrizamide for myelography. Nine patients had a CT without intrathecal contrast material 1 to several days before the myelogram. Six patients had myelography only, and three patients had CT only. All studies were evaluated for the location and type of disease in a forced choice fashion. Independent of the surgically correlated levels, there was 86.8% agreement between the MR and CT studies in all patients at 151 levels and 87.2% agreement between MR and myelography at 218 levels. At the operative levels, there was 82.6% agreement between MR and surgical findings for both type and location of disease; 83% agreement between CT and surgical findings; and 71.8% agreement between myelography and surgical findings. There was 92.5% agreement when MR and CT were used jointly, and 89.4% agreement when CT and myelography were used jointly. The results of this study indicate that a technically adequate MR examination was equivalent to CT and myelography in the diagnosis of lumbar canal stenosis and herniated disk disease. CT and MR can be complementary studies, and surface coil MR can be viewed as an alternative to myelography.     

Cerebral amyloid angiopathy-related inflammation: imaging findings and clinical outcome

Introduction

We aim to investigate the clinical onset, computed tomography (CT) and magnetic resonance (MR) imaging findings, and follow-up of patients with cerebral amyloid angiopathy (CAA)-related inflammation, an uncommon but clinically striking presentation of CAA.

Methods

We retrospectively reviewed the clinical manifestations, CT/MR imaging findings, and outcome of ten consecutive patients with CAA-related inflammation. In each patient, a brain CT study was performed at hospital admission, and brain MR imaging was carried out 2 to 4 days later. Clinical and radiologic follow-up findings were evaluated in all patients.

Results

The most common clinical onset was rapidly progressive cognitive decline, followed by focal neurological signs. Brain CT/MR showed unenhanced expansive subcortical lesions, corresponding to areas of vasogenic edema, associated with chronic lobar, cortical, or cortical–subcortical micro/macrohemorrhages. Clinical symptoms recovered in a few weeks under treatment in eight patients and spontaneously in the remaining two. MRI follow-up at 2 to 12 months after treatment showed resolution of the lesions. Three patients experienced symptomatic disease recurrence, with new lesions on CT/MR.

Conclusion

In the absence of histological data, early recognition of the clinical symptoms and typical radiologic features of CAA-related inflammation is essential to enable timely establishment of proper treatment.     

Extrahepatic abdominal imaging in patients with malignancy: comparison of MR imaging and helical CT in 164 patients

The purpose of this study was to compare the performance of magnetic resonance (MR) imaging using currently available techniques with contrast-enhanced single-phase helical computed tomography (CT) in depicting extrahepatic disease in patients with malignancy. At two institutions, 164 patients with known or suspected malignancy underwent abdominal imaging with contrast-enhanced helical CT and MR imaging. The prospective interpretations of the CT scans and MR examinations were used to assess the sensitivity of each imaging test in detecting benign and malignant extrahepatic disease at 17 anatomic sites. Imaging findings were compared with results of surgery in 57 patients and with the combined results of image-guided biopsy, follow-up cross-sectional imaging studies, other concurrent imaging tests, and clinical follow-up. For the 164 patients, helical CT scans depicted 221 of 316 (70%) sites of proven extrahepatic tumor compared with 288 sites (91%) (P < 0.0001) for MR imaging. For the 57 patients who underwent exploratory laparotomy, helical CT scans depicted 101 of 154 (66%) findings of surgically confirmed extrahepatic tumor compared with MR imaging, which depicted 139 sites (90%) (P < 0.0001). Anatomic sites at which MR imaging showed a significantly greater detection of extrahepatic tumor included the peritoneum, bowel, and vascular and osseous structures. For depiction of benign extrahepatic disease, there was no significant difference between helical CT and MR imaging. MR imaging, using currently available T1-weighted, RARE T2-weighted, and gadolinium-enhanced imaging, is effective in depicting extrahepatic disease in patients with malignancy. Compared with single-phase helical CT scanning, MR imaging shows an advantage in depicting tumor involving the peritoneum, omentum, bowel, and osseous and vascular structures.     

Brachial plexus: correlation of MR imaging with CT and pathologic findings

Thirty-two patients with symptoms referable to the brachial plexus were evaluated with magnetic resonance (MR) imaging. Sixteen patients had undergone concurrent computed tomography (CT). MR imaging demonstrated normal findings in 16, 12 neoplasms, three cases of trauma, and one case of possible neural edema. Of the 16 patients with normal findings on MR images, eight had CT scans that were also normal. In one patient, MR images showed that the "mass" seen on CT was actually a tortuous blood vessel. In six of the 12 cases of neoplasm in which CT scans were available, MR imaging revealed more extensive disease. In the other six cases of tumor, MR imaging provided sufficient clinical information to obviate the need for CT or any other imaging modality. MR imaging provided definitive diagnoses in the three cases of trauma without further imaging. In one patient with paresthesia, MR imaging showed high signal intensity of the nerves on T2-weighted images, which was compatible with neural edema. A concurrent CT scan was normal.