Nonlissencephalic cortical dysplasias: correlation of imaging findings with clinical deficits.

PURPOSE: To establish correlations between MR patterns and clinical outcome in patients with nonlissencephalic cortical dysplasias. PATIENTS AND METHODS: MR and clinical data from 36 patients with cerebral cortical gyral anomalies (other than classical type I or type II lissencephaly) were retrospectively reviewed. RESULT: The five patients with diffuse cortical dysplasia, including two with congenital infections, had microcephaly and severe development delay from a very early age. Infantile spasms occurred in three of the five. Focal areas of cortical dysplasia were most common in the frontal lobes, but were seen in all areas of the brain. The most common MR appearances were 1) a thickened, irregularly bumpy cortex with shallow, wide sulci, and 2) a deep infolding of thickened cortex. The twelve patients with bilateral focal dysplasia had a high incidence of bilateral motor dysfunction (67%), delayed speech (67%), and generalized developmental delay (92%). When the dysplasia was unilateral, contralateral spastic hemiplegia or monoplegia was present in 14 of 19 patients (74%), but dysphasia was uncommon, even in patients with dysplasia in the frontal lobe of the dominant hemisphere. CONCLUSION: Surgical resection of focal areas of cortical dysplasia in patients with medically refractory seizures is becoming more common, and the neuroradiologist will play an increasingly important role in the initial diagnosis and delineation of these anomalies.     

Sporadic meningioangiomatosis: imaging findings with histopathologic correlations in seven patients

Introduction

Meningioangiomatosis (MA) is a rare benign cerebral lesion. We aimed to evaluate the CT and MR features of sporadic MA, with a focus on the correlation between imaging and histopathologic findings.

Methods

CT (n?=?7) and MR (n?=?8) images of eight patients (6 men and 2 women; mean age, 12.8 years; range, 4–22 years) with pathologically proven MA were retrospectively reviewed. After dividing the MA lesions according to their distribution into cortical and subcortical white matter components, the morphologic characteristics were analyzed and correlated with histopathologic findings in seven patients.

Results

CT and MR images showed cortical (n?=?4, 50 %) and subcortical white matter (n?=?7, 88 %) components of MA. All four cortical components revealed hyperattenuation on CT scan and T1 isointensity/T2 hypointensity on MR images, whereas subcortical white matter components showed hypoattenuation on CT scan and T1 hypointensity/T2 hyperintensity on MR images. Two cortical components (25 %) demonstrated enhancement and one subcortical white matter component demonstrated cystic change. Seven cases were available for imaging-histopathologic correlation. In all seven cases, the cortex was involved by MA and six patients (86 %) showed subcortical white matter involvement by MA. There were excellent correlations between the imaging and histopathologic findings in subcortical white matter components, and the accuracy was 100 % (seven of seven); whereas there were poor correlations in cortical components, and the accuracy was 43 % (three of seven).

Conclusions

The cerebral cortex and subcortical white matter were concomitantly involved by MA. Subcortical white matter components of MA were more apparent than cortical components on CT and MR imaging.     

Focal liver lesions: MR imaging with Mn-DPDP--initial clinical results in 40 patients.

Manganese (II) N,N'-dipyridoxylethylenediamine-N,N'-diacetate-5,5'-bis(phosphate) (DPDP) was evaluated as a contrast agent for magnetic resonance (MR) imaging (1.5 T) of focal liver lesions in 40 patients. Doses of 5 and 10 mumol/kg were administered intravenously. Mn-DPDP-enhanced T1-weighted images were compared quantitatively and subjectively with standard T1- and T2-weighted nonenhanced images. Use of Mn-DPDP resulted in a statistically significant increase in signal intensity of liver parenchyma in T1-weighted images at both doses. No enhancement was seen in metastases, cholangiocarcinomas, or lymphomas, while all hepatocellular carcinomas were enhanced. Enhancement was seen in focal nodular hyperplasia and in regenerative nodules. The lesion-to-liver contrast in Mn-DPDP-enhanced gradient-recalled-echo images was superior to that of all precontrast images (P less than .01). The number of nonenhancing malignant liver lesions detected in spin-echo (SE) images was increased (272 in T2-weighted SE images vs 390 in T1-weighted Mn-DPDP-enhanced SE images). Image interpretation (eg, visualization and demarcation of the lesions) was markedly better in Mn-DPDP-enhanced images than in all precontrast images (P less than .001).     

Rectal carcinoma treated by preoperative irradiation: MR imaging and histopathologic correlation.

We evaluated the role of MR imaging in assessing the effect of preoperative irradiation in 11 patients with primary rectal carcinoma. Findings on MR images obtained before radiotherapy and 5-6 weeks afterward were analyzed and correlated with the histopathological findings (nine patients) or the findings at laparotomy (two patients). Before irradiation, the tumor volumes on MR images were between 3.3 and 51.7 cm3 (mean 19.7 cm3). After irradiation, the volumes were from 0.8 to 33.2 cm3 (mean, 10.4 cm3), representing a decrease in volume of 11% to 88% (mean, 55%). On the MR images obtained before irradiation, the tumors were confined to the bowel wall in four cases (stage A-B1), penetrated the perirectal fat in six cases (stage B2), and involved an adjacent organ in one case (stage B3). After irradiation, no apparent changes were seen in the MR appearance of the local tumor stage in nine of the 11 patients. In one patient, progression of stage was suspected on the postirradiation MR images, but this was not confirmed at histologic examination. In one patient, possible downstaging occurred after irradiation, although this could not be proved. Our findings suggest that MR imaging may be useful for determining the effect of preoperative radiotherapy on rectal carcinomas.     

Liver adenomatosis: clinical, histopathologic, and imaging findings in 15 patients

PURPOSE: To report and correlate the clinical, histopathologic, and imaging findings in 15 patients with liver adenomatosis. MATERIALS AND METHODS: Fifteen adult patients had more than 10 hepatic adenomas each and no history of glycogen storage disease or anabolic steroid use. Ten of them underwent bolus-enhanced dynamic computed tomography (CT) with or without magnetic resonance (MR) imaging, ultrasonography, and/or angiography. RESULTS: Clinical abnormalities included abdominal pain in 11 (73%) and hepatomegaly in 10 (67%) patients, and abnormal liver function in 10 (91%) of 11 patients. The number of adenomas in each patient was 10-50 at imaging, but many more lesions were found in the resected specimens. Hemorrhage was commonly found within adenomas at histopathologic analysis, but only four patients had clinical and imaging evidence of substantial hemorrhage. In all patients, the adenomas increased over time, and two patients developed hepatocellular carcinoma. CT and MR features of the adenomas included evidence of hypervascularity (63%), intratumoral fat (50% of patients at CT, 80% at MR), and decreased conspicuity at portal venous and delayed-phase imaging. Fifty percent of patients had congenital or acquired hepatic vascular abnormalities. CONCLUSION: The imaging and histopathologic features of individual adenomatous lesions are similar to those reported in young women who are taking oral contraceptives. However, the lesions in liver adenomatosis are not steroid dependent but rather multiple, progressive, and symptomatic, and they are more likely to lead to impaired liver function, hemorrhage, and perhaps malignant degeneration.     

Magnetization transfer MR imaging in patients with posttraumatic epilepsy

BACKGROUND AND PURPOSE: Intractable epilepsy is a well-recognized complication following head trauma, and many factors have been implicated in its pathogenesis. This study was performed to determine the severity of tissue damage after severe head injury as assessed with magnetization transfer (MT) MR imaging and the relationship of this damage with seizure intractability. METHODS: Forty-four patients, 13 without seizures (disease controls) and 31 with seizures, underwent T1-weighted MT MR imaging 1-10 years after head trauma. Phase-corrected gradient-echo (GRE) imaging was also performed in all patients to look for the presence of hemosiderin. All patients were evaluated for the presence of an MT abnormality beyond an abnormality seen on T2-weighted images, an MT abnormality within a T2 abnormality, and hemosiderin deposition. RESULTS: Patients with an MT abnormality beyond a T2 abnormality had a significantly higher intractability of seizures compared with those with an MT abnormality within a T2 abnormality (P <.05). In addition, the mere presence of hemosiderin deposit was not associated with seizure intractability; however, gliosis around the hemosiderin as seen on T1-weighted MT images was associated with seizure intractability. CONCLUSIONS: T1-weighted MT imaging may be of value in predicting the intractability of the seizure in delayed posttraumatic epilepsy.     

CT and MR imaging evaluation of neck infections with clinical correlations

Infection of the neck is a common clinical problem in all age groups, especially children and young adults. The clinical symptoms and signs are often suggestive of the diagnosis. Imaging studies including CT and MR imaging are frequently required to confirm the diagnosis but more importantly to localize the infectious process and search for and delineate an abscess cavity. Ultrasound has also been used in the evaluation of superficial neck infections, especially to determine fluid accumulation. Conventional films consisting of an anteroposterior and lateral view were the examination before the introduction of CT in 1972. Conventional films can still be used for a preliminary survey, especially of the retropharyngeal space when there is a question of a retropharyngeal phlegmon or abscess.     

Visualization of inner ear dysplasias in patients with sensorineural hearing loss : High-resolution MR imaging and volume-rendered reconstructions

Purpose: We evaluated a data acquisition and post-processing protocol for inner ear (IE) assessment by MR imaging in patients, suffering from various labyrinth malformations.Material and Methods: MR IE studies of 158 consecutive patients (316 IEs) suffering from sensorineural hearing loss without evidence of an acoustic neurinoma were reviewed for pathologies of the IE and internal acoustic meatus. High-resolution MR data of all abnormal IE studies (n=45) were post-processed to previously standardized 3D volume rendered (VR) reconstructions.Results: In 9 patients (5.7%) the following IE dysplasias were detected: malformation of the cochlea (6 IEs), vestibulum (4 IEs), semicircular canals (12 IEs) and vestibular aqueduct/endolymphatic sac (10 IEs). One patient showed evidence of an aplasia of the vestibulocochlear nerve. In 4 patients multiple IE dysplasias were encountered. Comprehensive 3D visualization of all labyrinthine dysplasias was achieved by the use of two VR reconstructions. The overall time for bilateral IE assessment amounted to 30-35 min.Conclusion: The imaging protocol allows for rapid and comprehensive visualization of various IE dysplasias, based on a limited number of VR reconstructions.     

Diffusion and perfusion MR imaging in cases of Alzheimer's disease: correlations with cortical atrophy and lesion load.

BACKGROUND AND PURPOSE: Perfusion and diffusion-weighted MR imaging are powerful new imaging techniques for evaluating tissue pathophysiology in association with many neurologic disorders, such as neurodegenerative diseases. The purpose of our study was to evaluate the sensitivity and specificity of dynamic susceptibility contrast-enhanced MR imaging and diffusion-weighted MR imaging in cases of Alzheimer's disease and to assess the role of atrophy in the quantification of cortical perfusion. METHODS: Thirty-nine participants were studied: 18 patients with moderate cognitive impairment with probable Alzheimer's disease, 16 patients with mild impairment with possible or probable Alzheimer's disease, and 15 group-matched elderly healthy comparison volunteers. Relative values of temporoparietal, sensorimotor, and hippocampal regional cerebral blood volume (rCBV) were measured as a percentage of cerebellar rCBV, and group classification was assessed with logistic regression. Brain atrophy was used as a covariate to assess its role in rCBV quantification. Regions of interest placed on orientation-independent apparent diffusion coefficient maps allowed the calculation of apparent diffusion coefficient values and relative anisotropic indices of the head of the caudate nuclei, thalamus, parietal, frontal, and hippocampal cortices bilaterally, genu and splenium of corpus callosum, and anterior and posterior white matter in patients with Alzheimer's disease and in control volunteers. RESULTS: Temporoparietal rCBV ratios were reduced bilaterally in the patients with Alzheimer's disease. Sensitivity was 91% in moderately affected patients with Alzheimer's disease and 90% in patients with mild cases. Specificity was 87% in healthy comparison volunteers. Lower values of sensitivity and specificity were obtained for sensorimotor (73%, 50%, and 67%, respectively) and hippocampal cortices (80%, 80%, and 65%, respectively). Using brain atrophy as a covariate, patients with Alzheimer's disease still showed a statistically significant reduction of rCBV compared with control volunteers. Diffusion-weighted MR imaging analysis only showed a trend, with no statistic significance, of reduction of anisotropy in posterior white matter. CONCLUSION: Dynamic susceptibility contrast-enhanced MR imaging of rCBV may be an alternative to nuclear medicine imaging for the evaluation of patients with Alzheimer's disease. When brain atrophy is used as a covariate, differences in rCBV still persist between patients with Alzheimer's disease and control volunteers, suggesting that perfusion impairment is unrelated to atrophy. No significant results for either white or gray matter were obtained using diffusion-weighted MR imaging.     

Transneuronal degeneration in patients with temporal lobe epilepsy: evaluation by MR imaging

The aim of this study was to assess the MR imaging findings of transneuronal degeneration of limbic system in the patients with temporal lobe epilepsy, and to detect the influence of surgery on the anatomy of the limbic system. Axial and coronal T1- and T2-weighted MR images were retrospectively analyzed in 34 patients with temporal lobe epilepsy, focusing on transneuronal degeneration. In 17 of the 34 patients, MR images were also analyzed after selective amygdalo-hippocampectomy. Atrophy of the fornix, mamillary body, mamillothalamic tract (MTT), and thalamus ipsilateral to the epileptic focus was demonstrated on MR images in 14.7, 17.6, 8.8, and 11.8% of the 34 patients, respectively. Focal hyperintensity of the thalamus was found on T2-weighted images in 8.8% of the 34 patients. In 17 patients who were evaluated before and after surgery, transneuronal degeneration was seen more frequently after surgery: fornix (11.8 vs 29.4%), mamillary body (11.8 vs 52.9%), MTT (5.9 vs 11.8%), and thalamus (11.8 vs 11.8%). Transneuronal degeneration of the limbic system is clearly demonstrated by MR imaging in patients with temporal lobe epilepsy, and surgical intervention induces transneuronal degeneration more frequently.     

Cerebral aspergillosis: MR imaging and histopathologic correlation.

The authors report a case of intracranial aspergillosis secondary to immunosuppression. Signal intensity changes in the lesion on brain MR are compared with gross and histopathologic findings at autopsy. A peripheral ring of low signal intensity relates to a dense population of Aspergillus hyphal elements and small areas of hemorrhage. CT findings are included for comparison.     

MR imaging in the presurgical workup of patients with drug-resistant epilepsy

BACKGROUND AND PURPOSE: Whether an epileptic lesion is detected with MR imaging depends on the quality of the images and the expertise of the reader. We analyzed the role of 1.5-T MR imaging in the presurgical evaluation of patients with drug-resistant epilepsy at one center. METHODS: In a 2-year prospective study, 385 patients with drug-resistant epilepsy underwent standardized MR imaging at 1.5 T. We analyzed whether lesions were detected, whether they were precisely characterized by MR imaging, and whether lesion characterization allowed us to estimate seizure outcomes. RESULTS: Lesions were found on MR images in 318 patients (83%). Following presurgical evaluation, 209 (66%) underwent surgery, and 109 (34%) did not. Freedom from seizures was achieved in 130 (70%) of 186 patients. Nine (14%) of 66 patients without an MR imaging lesion underwent surgery; histopathologic findings were unrevealing in seven patients, and five (56%) achieved freedom from seizures. Hippocampal sclerosis was the most common lesion (52%) and correctly characterized in 101 (97%) of 104 patients. Glioneuronal tumors (20%) were sometimes imprecisely characterized: Four nonenhancing gangliogliomas were mistaken for focal cortical dysplasias. Outcomes were not different between lesion groups. However, there were trends toward a favorable outcome for focal cortical dysplasias with balloon cells and an unfavorable outcome for gyral scars. CONCLUSION: MR imaging detection of lesions influences further presurgical workup, though lesion characterization does not allow us to predict seizure outcome. If MR imaging fails to depict a lesion and patients undergo surgery because of electrophysiologic findings, histopathologic findings are often unrevealing.     

Lymphomas: MR imaging contrast characteristics with clinical-pathologic correlations

Mean pixel intensity ratios, contrast parameters, and T1-T2 cross products relative to fat and muscle were derived from T1-weighted and T2-weighted images obtained at 1.5 T in 32 patients with non-Hodgkin lymphomas and 20 with Hodgkin disease. Lymphomas were relatively homogeneous: Only 6% of the lesions had broad, bimodal, or skewed distributions of pixel intensities that could be attributed to intrinsic heterogeneity. On average, lymphomas were hypointense to fat and slightly hyperintense to muscle in T1-weighted images but isointense to fat and hyperintense to muscle in T2-weighted images. Low-, intermediate-, and high-grade non-Hodgkin lymphomas had identical imaging characteristics. The most striking and significant result was the greater brightness of lymphomas with dense fibrosis in T2-weighted images, which explains the trend toward greater brightness of Hodgkin disease than that of non-Hodgkin lymphomas and greater brightness of lymphomas in the mediastinum than of lymphomas in other locations. Neither a contrast parameter nor the T1-T2 cross product added information not evident with the use of simple mean pixel intensity ratios.     

Prostatic carcinoma and benign prostatic hyperplasia: MR imaging with histopathologic correlation

Twenty-eight patients with prostatic carcinoma who underwent magnetic resonance (MR) imaging and subsequent radical prostatectomy were studied. The resected prostates were sectioned axially, and the whole-mount prostatic specimen was compared with the corresponding MR images. The carcinoma could be identified in 20 cases (71%), but the tumor volume was underestimated in 12 patients (43%). In 19 of 20 visualized cases (95%), the carcinoma was seen as an area of low signal intensity within the peripheral zone on T2-weighted images. However, in one case the signal intensity of the carcinoma was higher than that of the remainder of the peripheral zone. All carcinomas were located within the peripheral zone. The accuracy of MR imaging in the prediction of extraglandular tumor spread was 82%, with a sensitivity of 37.5% and a specificity of 100%. Nineteen patients (67%) exhibited histologically benign hyperplasia, which could be identified on MR images in 10 cases (53%). The signal intensities of the nodules varied. All areas of benign hyperplasia were located within the central zone. The location of the pathologic changes must therefore be considered in differential diagnosis.     

前列腺癌和增生的MRI与病理对照研究

目的 研究前列腺癌不同ＭＲＩ表现的病理基础,以提高ＭＲＩ对前列腺癌和增生诊断的准确性。方法 观察经病理证实的４３例前列腺癌和４０例增生患者的前列腺形态及信号改变,并加以比较,前列腺癌组中１７例取前列腺左右两侧外周区上中下、左右移行区上下共１０点进行穿刺,对穿刺组织分别进行病理检查,同时计算癌变组织占总穿刺体积的百分比,并与其ＭＲＩ进行对比。结果 前列腺癌形态规则３１例,不规则１２例,增生组分别为３