Brain MR in Fukuyama congenital muscular dystrophy.

PURPOSETo determine the MR characteristics of brain abnormalities in Fukuyama congenital muscular dystrophy (FCMD).METHODSWe reviewed 30 MR examinations of 21 patients with FCMD to assess cerebral and cerebellar cortical dysplasia, white matter changes, and miscellaneous abnormalities.RESULTSOn MR images, all patients had thick and bumpy cortices with shallow sulci corresponding to polymicrogyria, and 12 patients had pachygyric cortices with smooth surfaces, corresponding to type II lissencephaly. Both types of cortical dysplasia had characteristic distributions: the first type involved the frontal lobe in all 21 patients and also the parietotemporal lobe in 6 patients; the second type involved the temporooccipital lobes. Eighteen patients had prolonged T1 and T2 signal in the white matter, which was indistinct in neonates and seen infrequently in adolescents. In four patients, abnormal vessels were seen within the pachygyric cortices.CONCLUSIONMR studies of the brain show findings consistent with the known characteristics of FCMD. The MR detection of the two types of cerebral cortical dysplasia with characteristic distribution and cerebellar abnormalities is helpful in the differential and early diagnosis of FCMD.     

Cerebellar MR in Fukuyama congenital muscular dystrophy: polymicrogyria with cystic lesions.

PURPOSETo determine the MR appearance of cerebellar abnormalities in Fukuyama congenital muscular dystrophy.METHODSWe reviewed brain MR images of 25 patients with Fukuyama congenital muscular dystrophy and examined the autopsy specimens of a 23-month-old girl with the disease to determine the pathologic nature of the MR findings.RESULTSMR studies revealed two characteristic cerebellar abnormalities: (a) disorganized cerebellar folia (16 cases) that were recognized as unusual distortions of the cortex; and (b) clusters of intraparenchymal cysts (23 cases). The two lesions were located close to each other, and milder lesions tended to affect only the superior semilunar lobule. The autopsy specimen revealed small cerebellar cysts, which consisted of dilated subarachnoid spaces buried beneath the malformed cortex.CONCLUSIONThe disorganized folia represent cerebellar polymicrogyria, and the presence of cerebellar cysts is related to the polymicrogyria. These two MR changes are often present in Fukuyama congenital muscular dystrophy and are distinct enough to suggest the radiologic diagnosis.     

MR imaging of dural arteriovenous fistulas draining into cerebellar cortical veins

BACKGROUND AND PURPOSE: Retrograde leptomeningeal venous drainage (RLVD) in a dural arteriovenous fistula (DAVF) is associated with intracerebral hemorrhage, nonhemorrhagic neurologic deficit, or death, and recognizing the presence of this drainage is important. We investigated the MR findings of DAVFs draining into cerebellar cortical veins and compared these findings with those of conventional angiography. METHODS: The MR and angiographic findings of six patients (five men, one woman; mean age, 73.4 years) with DAVF with RLVD into cerebellar cortical veins were reviewed retrospectively. Signal intensity characteristics, contrast material enhancement, topography of the lesion, and presence of signal voids were evaluated on MR images. Site of the shunt, feeding arteries, and draining veins were evaluated on angiograms. RESULTS: In all patients, MR images showed high signal intensity on T2-weighted images and peripheral enhancement on gadolinium-enhanced T1-weighted images at the inferior aspect of the cerebellar hemisphere. A combination of posterior meningeal and occipital arteries was the most frequent blood supply (83%) for these DAVFs. In all six patients, the inferior hemispheric vein was the primary draining vein. CONCLUSION: The characteristic MR findings of DAVF draining into cerebellar cortical veins represent venous congestive encephalopathy in the territory of the involved cortical vein.     

Neuropathologic and MR imaging correlation in a neonatal case of cerebellar cortical dysplasia

Little documentation of the correlation between MR imaging findings in isolated cerebellar cortical dysplasia (CCD) and its neuropathologic characteristics exists in the recent literature. We documented a postmortem neuropathologic study of a clinically and radiologically well-documented case of CCD in a neonate with severe hypotonia and status epilepticus. MR imaging revealed a global vermian hypoplasia with marked cortical dysplasia. CCD was associated with a voluminous heterotopic mass. The postmortem neuropathologic study confirmed vermian hypoplasia and CCD, which consisted of right cerebellar cortical polymicrogyria with subcortical heterotopia. CCD is a pathologic entity that could be well diagnosed with MR imaging even in the neonatal period.     

Proton MR spectroscopy of polymicrogyria and heterotopia

BACKGROUND AND PURPOSE: Proton MR spectroscopy of the brain allows noninvasive in vivo assessment of metabolites, which may be useful in understanding the biology of malformations of cortical development. The aim of this study was to determine the MR spectroscopic characteristics of polymicrogyria and heterotopia compared with those of normal frontal lobe white matter. METHODS: We recruited 22 patients with radiographic findings characteristic of polymicrogyria, nine patients with radiographic findings characteristic of heterotopia, and 10 control subjects into the study. The MR imaging technique consisted of high-spatial-resolution axial dual-echo and gradient-echo 3D volume imaging. A single-voxel point-resolved technique (1600/135 [TR/TE]) was used to acquire spectra from the region of neocortical malformation and from frontal lobe white matter in control subjects. The differences in N-acetyl moieties (NA)/creatine (Cr), NA/choline (Cho), and Cho/Cr ratios among patients with heterotopia, those with polymicrogyria, and control subjects were compared by using the Kruskal-Wallis test followed by the Mann-Whitney U (Wilcoxon) test. RESULTS: No statistically significant differences were noted in the NA/Cr, NA/Cho, and Cho/Cr ratios between the polymicrogyria group and controls, the heterotopia group and controls, or the polymicrogyria and heterotopia groups. CONCLUSION: Both heterotopia and polymicrogyria are malformations of cortical development that occur at a relatively late stage of brain development. The neurons and glia in these lesions are mature, and the metabolites appear to be similar to those of normal adult frontal white matter.     

Magnetic resonance perfusion imaging in malformations of cortical development

BACKGROUND: Malformations of cortical development vary in neuronal maturity and level of functioning. PURPOSE: To characterize regional relative cerebral blood volume (rCBV) and difference in first moment transit time (TTfm) in polymicrogyria and cortical tubers using magnetic resonance (MR) perfusion imaging. MATERIAL AND METHODS: MR imaging and dynamic T2*-weighted MR perfusion imaging were performed in 13 patients with tuberous sclerosis complex, 10 with polymicrogyria, and 18 controls with developmental delay but no macroscopic brain abnormality. Regions of interest were placed in cortical tubers or polymicrogyric cortex and in the contralateral normal-appearing side in patients with malformations. In "control" subjects, regions of interest were placed in the frontal and parietal lobes in both hemispheres. The rCBV and TTfm of the tuber/contralateral side (rCBV(R)TSC and DeltaTT(FM)TSC) as well as those of the polymicrogyria/contralateral side (rCBV(R)PMG and DeltaTT(FM)PMG) were assessed. The right-to-left asymmetry of rCBV and TTfm in the control group was also assessed (rCBV(R)Controls and DeltaTT(FM)Controls). RESULTS: There was no significant asymmetry between right and left rCBV or TTfm (P>0.05) in controls. There was significant reduction in rCBV(R)TSC compared to rCBV(R)Controls (P<0.05), but no significant difference in DeltaTT(FM)TSC compared to DeltaTT(FM)Controls (P>0.05). There were no significant differences between rCBV(R)PMG and rCBV(R)Controls (P>0.05) or DeltaTT(FM)PMG and DeltaTT(FM)Controls (P>0.05). CONCLUSION: Our findings imply that cerebral blood volume of polymicrogyria is similar to normal cortex, but there is reduced cerebral blood volume in cortical tubers. The lower rCBV ratio of cortical tubers may be related to known differences in pathogenetic timing of the underlying abnormalities during brain development or the presence of gliosis.     

Magnetic resonance imaging findings of Machado-Joseph disease: histopathologic correlation

PURPOSE: To determine the characteristic magnetic resonance imaging (MRI) findings of early- and late-stage Machado-Joseph disease (MJD) and to examine correlation with pathologic specimens. PATIENTS AND METHODS: Four patients genetically diagnosed with MJD and a familial case of MJD were all examined using MRI. Machado-Joseph disease was pathologically confirmed in one of the four genetically diagnosed patients, and the findings were compared with the MRI results. RESULTS: In all three patients who had MJD for less than 8 years, MRI confirmed mild cerebellar atrophy, particularly in the vermis, and atrophic changes in the superior cerebellar peduncle. Mild pontine atrophy was observed in these three patients. Atrophic changes in the pontine tegmentum were more prominent than those of the pontine base in these patients. Two of the three patients showed mild frontal atrophy. Of the five total patients, two had the disease for over 10 years and showed progressive atrophy of the brainstem and mild frontal atrophy. These two patients also showed pallidal atrophy. One autopsied case in which the disease duration was 17 years showed a typical pathologic picture of MJD. Macroscopic findings for this patient showed marked atrophy of the pons, mild cerebellar atrophy (particularly in the vermis), marked atrophy of the superior cerebellar peduncle, severe involvement of motor nuclei, and atrophy and discoloration of the pallidum and subthalamic nuclei. CONCLUSION: In the early stages of MJD, mild pontine atrophy, particularly in the tegmentum, and mild cerebellar atrophy are typical MRI findings. Atrophic changes in the brainstem may be progressive. Pallidal atrophy may be observed in patients with long disease duration. These findings correlated with the pathologic findings.     

Advanced imaging of melorheostosis with emphasis on MRI

Objective: To describe the CT and MR imaging appearance of both osseous and extraosseous manifestations of melorheostosis. Design and patients: We retrospectively reviewed the CT (n=7) and/or MR imaging findings (n=12) of 17 patients with characteristic radiographic findings of melorheostosis (undulating cortical hyperostosis with marked uptake on radionuclide bone scintigraphy). Results: CT and MR imaging revealed cortical hyperostosis as high attenuation and low signal intensity on all MR pulse sequences, respectively. Encroachment on the marrow space was seen in all cases resulting from endosteal involvement. Thirteen patients demonstrated 14 soft tissue masses with infiltrative margins in 80% of cases and seven showed extensive mineralization on CT or MR imaging (low intensity on all pulse sequences). Seven soft tissue masses were predominantly nonmineralized with intermediate signal intensity on T1-weighted and intermediate to high signal on T2-weighted MR images corresponding to vascularized fibrous tissue with variable collagen content pathologically. Enhancement after intravenous gadolinium was seen in all patients imaged with soft tissue masses (n=2). Two patients demonstrated muscle atrophy resulting from nerve involvement. Conclusions: The osseous abnormalities in melorheostosis are identical on advanced imaging and radiographs. Mineralized or nonmineralized soft tissue masses should be recognized as another manifestation of this disease as opposed to a more ominous finding, making biopsy unwarrranted. Received: 16 January 2001 Accepted: 21 February 2001     

Crossed cerebellar hypoperfusion in unilateral major cerebral artery occlusive disorders.

We evaluated regional blood flow and oxygen metabolism in the cerebral and cerebellar cortices of 15 patients with unilateral major cerebral artery occlusive disorders with PET. These patients showed a cortical blood flow asymmetry in middle cerebral artery distribution. Only subcortical abnormalities were detected on computed tomography. Nine patients showed crossed cerebellar hypoperfusion, a reduction in contralateral cerebellar blood flow, while six did not. No difference in the degree of cerebral blood flow asymmetry existed between the two patient groups. However, oxygen metabolism asymmetry was more pronounced and was more closely matched to blood flow asymmetry in patients with crossed cerebellar hypoperfusion. These findings suggest that a major cause of cerebral cortical blood flow reduction is reduced metabolic demand in patients with crossed cerebellar hypoperfusion. Crossed cerebellar hypoperfusion may have clinical significance as a reflection of the cerebral metabolic state on blood flow images.     

Reye's syndrome with cortical laminar necrosis: MRI

Serial MRI findings are described in two patients with Reye's syndrome, demonstrating diffuse cortical and white matter changes. In the acute stage, T2-weighted images showed subtle but definite laminar high signal and contrast-enhanced T1-weighted images laminar enhancement, along the entire cerebral cortexbilateraly. In the chronic stage, unenhanced T1-weighted images showed diffuse cortical laminar high signal. These characteristic MRI features seemed very similar to those of laminar cortical necrosis in hypoxic brain damage. MRI also displayed delayed white matter changes with cerebral atrophy.     

Posterior reversible encephalopathy syndrome: utility of fluid-attenuated inversion recovery MR imaging in the detection of cortical and subcortical lesions

BACKGROUND AND PURPOSE: Posterior reversible encephalopathy syndrome (PRES) is typically characterized by headache, altered mental functioning, seizures, and visual loss associated with imaging findings of bilateral subcortical and cortical edema with a predominantly posterior distribution. Our goal was to determine whether fluid-attenuated inversion recovery (FLAIR) imaging improves the ability to detect subtle peripheral lesions of PRES, as compared with conventional MR techniques. METHODS: Sixteen patients with clinical and imaging findings consistent with PRES were studied. Thirteen patients had undergone transplantation and had cyclosporin A neurotoxicity. Fast-FLAIR images were compared with spin-echo proton density- and T2-weighted images. RESULTS: FLAIR imaging improved diagnostic confidence and conspicuity of the T2 hyperintense lesions of PRES, typically in the subcortical white matter of the parietooccipital regions bilaterally. On all 23 abnormal MR studies, FLAIR was judged superior to proton density- and T2-weighted images for the detection of PRES in the supratentorial brain. In a mean of 6.7 of 23 studies, FLAIR findings prompted a raise in the grade of disease severity. FLAIR also showed cortical involvement in 94% of patients with PRES and in a mean of 46% of the total lesion burden. In four cases, subtle lesions were virtually undetectable without FLAIR. Brain stem or cerebellar disease was encountered in 56% of patients. CONCLUSION: FLAIR improves the ability to diagnose and detect subcortical and cortical lesions in PRES as compared with proton density- and T2-weighted spin-echo images. We therefore believe that FLAIR should be performed in patients with suspected PRES to allow more confident recognition of the often subtle imaging abnormalities.     

Cerebellar vermian atrophy after neonatal hypoxic-ischemic encephalopathy

BACKGROUND AND PURPOSE: Although pathologic evidence of cerebellar injury due to birth asphyxia is well described, neuroimaging evidence is sparse. The primary purpose of this retrospective study was to evaluate the early and late imaging findings in the cerebellum of patients who had neonatal hypoxic-ischemic encephalopathy with thalamic edema shown by neonatal CT. The secondary aims were to validate thalamic edema shown by neonatal CT as a marker of thalamic injury and to assess the late cerebral cortical abnormalities associated with neonatal thalamic edema. METHODS: Fifty-five neonates with thalamic edema shown by CT performed when patients were 3 days old were identified from a cohort of full-term neonates with hypoxic-ischemic encephalopathy. Twenty-six of the 55 underwent follow-up neuroimaging. All sonograms, CT scans, and MR images of the brains of the 55 neonates were retrospectively reviewed by two pediatric neuroradiologists. The examinations were reviewed for evidence of hemorrhage, edema, atrophy, and CT attenuation or MR signal intensity abnormalities in the cerebellum, basal ganglia, and cerebral cortex. The neonatal autopsy findings in four cases were reviewed separately by a pediatric neuropathologist. RESULTS: Of the 55 neonates with thalamic edema shown by neonatal CT, 28 (51%) had thalamic edema with diffuse cerebral cortical edema, and 27 (49%) had thalamic edema without diffuse cortical edema. The cerebellar vermes appeared normal on all neonatal sonograms, CT scans, and MR images. However, atrophy of the cerebellar vermis was found in 12 (46%) of 26 patients by use of follow-up studies (95% CI, 27-65%). One of the 12 patients also had cerebellar hemispheric atrophy. Cerebellar vermian atrophy was shown at follow-up in eight (67%) of 12 patients who had neonatal thalamic edema with cortical sparing, compared with four (29%) of 14 patients who had thalamic edema with diffuse cortical edema. The difference did not reach statistical significance. The thalami appeared abnormal on follow-up neuroimages in 25 of 26 cases. Different patterns of cortical atrophy were observed on the images of patients who had thalamic edema with cortical sparing compared with those obtained in patients who had thalamic edema with cortical involvement. CONCLUSION: Cerebellar vermian atrophy is a frequent finding on follow-up images of patients in whom neonatal CT showed hypoxic-ischemic encephalopathy with abnormal thalami.     

Congenital cytomegalovirus infection of the brain: imaging analysis and embryologic considerations.

PURPOSETo analyze the cortical gyral patterns and myelination patterns in a series of patients with congenital cytomegalovirus infections involving the central nervous system, to correlate them with known developmental events, and to develop a consistent theory regarding their embryogenesis.METHODSThe MR (11 patients) and CT (four patients) studies of 11 patients with congenital cytomegalovirus infections involving the brain were retrospectively reviewed. Analysis was made of myelination patterns, cortical gyral patterns, other areas of maldeveloped brain, and focal brain lesions.RESULTSLissencephaly was found in four patients. These patients had very thin cerebral cortices, extremely diminished volume of white matter, delayed myelination, small cerebella, and very enlarged lateral ventricles. Focal areas of dysplastic cortex, presumably polymicrogyria, were found in five patients. These patients had slightly thickened irregular cerebral cortices, slightly diminished volume of white matter, delayed myelination, variably small cerebella, and slightly enlarged lateral ventricles. Two patients had normal cerebral cortices, slightly diminished volume of white matter, delayed myelination, normal cerebella, and slightly enlarged lateral ventricles. Periventricular lesions, representing calcification, or perhaps blood, were seen in all groups.CONCLUSIONSWe postulate that the patients with lissencephaly suffer injury before 16 or 18 weeks gestational age, whereas those with regions of polymicrogyria are injured between approximately 18 and 24 weeks gestational age. Those with normal gyral patterns are probably injured during the third trimester and may have active infections at birth. Moreover, we propose that the finding of cerebellar hypoplasia and myelination delay in association with diffuse lissencephaly or cortical dysplasia should suggest the diagnosis of congenital cytomegalovirus infection.     

Polymicrogyria without porencephaly/schizencephaly. MRI analysis of the spectrum and the prevalence of macroscopic findings in the clinical population

Although the diagnosis of polymicrogyria currently depends largely on non-invasive imaging, no large imaging-based studies of polymicrogyria have been reported. Previous anatomic studies of polymicrogyria have been based on autopsy studies and most of the cases in those series were associated with porencephaly or schizencephaly. This retrospective MRI analysis of a group of patients with polymicrogyria, without associated porencephaly or schizencephaly, was conducted to elucidate gross morphological findings of polymicrogyria in a clinical population. Seventy-one patients with polymicrogyria diagnosed by MRI were reviewed by two radiologists. The location of polymicrogyria, the associated white matter anomalies and other associated central nervous system anomalies were assessed. The polymicrogyria was unilateral in 30 (42%) patients, bilateral in 41 (58%) patients. The lobes involved in polymicrogyria were frontal 69%, parietal 63%, temporal 38%, and occipital 7%. The cortex in the Sylvian fissures was involved in 80%. The striate cortex, cingulate gyrus, hippocampus and the gyrus rectus were often spared. Diminished volume of white matter was noted in 48%, perivascular space dilatation in 27% and large cortical veins in 51%. Polymicrogyria develops in specific topological regions, the majority being centered around the Sylvian fissures, and a minority in the inferior and medial aspects of the cerebral hemispheres or the occipital lobes. Diminished volume of the white matter and dilated perivascular spaces deeply embedded close to the dysplastic cortex and abnormal cortical venous enlargement superficial to the dysplastic cortex may be useful adjuncts in making the diagnosis.     

MR of cerebellar cortical dysplasia.

MR imaging findings are described in four patients with cerebellar cortical dysplasia. Typically, cerebellar disorganized folia were seen as an irregular bumpy gray-white matter interface. In addition, cystlike cortical abnormalities were observed in two patients and associated supratentorial developmental abnormalities were seen in three patients. To our knowledge, cerebellar cortical dysplasia without supratentorial abnormalities, as seen in one patient, has not been reported before. We suggest that cerebellar cortical dysplasia represents a spectrum of abnormalities ranging from mild to extensive in severity.     

MR imaging of corpus callosotomy

MR findings in 13 patients who underwent corpus callosotomy for medically intractable seizures were reviewed. Preoperative MR studies were available in nine patients: five showed at least one morphological and/or MR signal abnormality including corpus callosal thinning (four cases), cerebellar atrophy (two cases), cortical atrophy (two cases), and periventricular hyperintensity on T2-weighted images (one case). Four patients had normal MR studies. Postoperative MR studies were obtained in 11 patients with subtotal callosotomy and two with total callosotomy. Of all pulse sequences, sagittal T1-weighted images best showed the surgical division, although two cases displayed a coaptation artifact, which was misleading. A surgical clip placed at the posterior extent of the callosotomy was best visualized with sagittal T1-weighted imaging. Two patients (15%) had MR findings consistent with subacute blood in the callosum, and three patients (23%) demonstrated parafalcial hyperintensity on T2-weighted images 1 week after callosotomy. Motion artifact was a significant problem with coronal imaging and T2-weighted pulse sequences in postoperative patients. Patients selected for corpus callosotomy may have a normal baseline MR or show nonspecific abnormalities. MR imaging is an effective method for evaluating callosal division, and in some cases, may demonstrate signal changes consistent with surgically related edema and/or blood.     

Analysis and classification of cerebellar malformations

BACKGROUND AND PURPOSE: Because of improved visualization of posterior fossa structures with MR imaging, cerebellar malformations are recognized with increasing frequency. Herein we attempt to describe and propose a rational classification of cerebellar malformations. METHODS: MR images obtained in 70 patients with cerebellar malformations were retrospectively reviewed. The cerebellar malformations were initially divided into those with hypoplasia and those with dysplasia. They were then divided into focal and diffuse malformations. Finally, they were separated according to other features, such as brain stem involvement and cerebral involvement. RESULTS: All patients with diffuse cerebellar dysplasia (muscular dystrophy [n = 10], cytomegalovirus [n = 6], lissencephaly [n = 3],) had abnormalities of the cerebrum. Patients with focal cerebellar dysplasia of the Joubert (n = 12) and rhombencephalosynapsis (n = 8) types had variable cerebral dysplasia. Patients with nonsyndromic focal cerebellar dysplasia (isolated focal cerebellar cortical dysplasia [n = 2], cerebellar heterotopia with cerebellar cortical dysplasia [n = 1], idiopathic diffuse cerebellar dysplasia [n = 1], Lhermitte-Duclos syndrome [n = 1]) and those with cerebellar hypoplasia (isolated cerebellar hypoplasia [n = 6], pontocerebellar hypoplasia type 1 [n = 1]) had normal cerebra. Patients with features of Dandy-Walker malformation (n = 19) had both hypoplasia and dysplasia of the cerebellum. No notable difference was found between the cerebella of patients with large fourth ventricle cysts (Dandy-Walker malformations) and those without large fourth ventricle cysts (isolated cerebellar hypoplasia). Therefore, the Dandy-Walker malformation seems to be heterogeneous. CONCLUSION: Use of this classification system helps in the segregation and understanding of the relationship among cerebellar malformations. Although it will undoubtedly require revisions, this classification is a first step in combining imaging with molecular biology to facilitate understanding of cerebellar development and maldevelopment.     

Infantile-onset spinocerebellar ataxia: MR and CT findings.

PURPOSETo report the MR and CT findings in a hereditary disease, infantile-onset spinocerebellar ataxia (IOSCA).METHODSWe studied the brains of 17 patients with infantile-onset spinocerebellar ataxia with CT and/or MR to determine the presence of cerebellar and brain stem atrophy and parenchymal lesions.RESULTSCerebellar cortical atrophy was seen in 13 patients. The degree of atrophy correlated with increasing age and clinical deterioration. Brain stem atrophy was seen in 8 patients. It was never severe, and the basis pontis was not flattened even in the most severe cases. Hyperintense lesions were noted within the white matter of cerebellum, in the dentate nuclei, and in the middle cerebellar peduncles in 3 patients. The upper cervical cord was seen in 9 patients and showed mild to moderate atrophy in 4. The basal ganglia and cerebral hemispheres were normal, except in 2 patients transient cortical and subcortical lesions developed during episodes of status epilepticus; mild cortical brain atrophy subsequently developed.CONCLUSIONThe brain MR and CT findings of patients with infantile-onset spinocerebellar ataxia correspond to the neuropathologic entities of cerebellar cortical atrophy, olivopontocerebellar atrophy, and spinocerebellar atrophy. The appearance of the findings followed a uniform time sequence from cerebellar cortical atrophy in the early stage of the disease to olivopontocerebellar atrophy and spinocerebellar atrophy in the later stage. The severity of atrophy correlated with clinical deterioration.     

MR of the brain in mitochondrial myopathy.

PURPOSETo determine the spectrum of MR findings in patients with mitochondrial myopathy and correlate them with central nervous system symptoms and signs.METHODSWe performed a prospective evaluation of the MR findings of eight patients with mitochondrial myopathy (three with Kearns-Sayre syndrome and five with chronic progressive external ophthalmoplegia), six of whom had central nervous system symptoms or signs (ataxia, sensorineural hearing loss, or cognitive dysfunction).RESULTSAll six patients with neurologic symptoms or signs had multiple abnormal MR findings, whereas patients without neurologic symptoms had either normal MR findings (one patient) or the solitary finding of cortical atrophy (one patient). Abnormal MR findings consisted of cerebral cortical atrophy (seven patients), cerebellar atrophy (six patients), and hyperintense signal abnormalities on T2-weighted images within the cerebral white matter (three patients), cerebellar white matter (one patient), basal ganglia (three patients), brain stem (one patient), and thalamus (one patient). In two patients, the cerebral white matter signal abnormalities were primarily peripheral and involved the arcuate fibers. All patients with ataxia had abnormal cerebellar findings on MR imaging, but there was poor correlation between other neurologic features and MR findings.CONCLUSIONSCerebral and cerebellar atrophy are the most common MR findings in Kearns-Sayre syndrome and chronic progressive external ophthalmoplegia. White matter and deep gray nuclei abnormalities, presumed to result from the diffuse spongiform encephalopathy reported in these patients, can also be seen. Patients with abnormal neurologic findings typically have multiple abnormalities on MR imaging, which frequently do not correlate with specific symptoms.     

上颌骨动静脉畸形的影像学特点

目的：研究上颌骨动静脉畸形（AVM）的X线、CT及MRI表现。方法对17例上颌骨AVM进行增强CT检查,其中3例行曲面断层X线检查,6例行增强MRI检查。结合血管造影（DSA）检查,分别观察病变部位、形态、边界、内部结构、邻近结构侵犯以及增强后密度／信号特征。结果病灶主要位于磨牙区（15／17）,临床以上颌牙龈反复渗血或急性出血者常见,其他表现包括脸部肿胀或搏动性肿物、脸部麻木。X线上主要表现为病灶部位的密度增高。增强CT上根据颌骨的改变可大致分为2类：Ⅰ类,膨胀性及溶骨性骨质破坏（n＝12）;Ⅱ类,弥漫性骨小梁增粗,类似“磨砂玻璃”样改变（n＝5）。17例患者均有不同程度的骨质破坏及周围软组织侵犯、可见供血动脉稍增粗或增粗迂曲的回流静脉、上颌窦腔不同程度抬高;14例患侧颈外静脉（或其他回流静脉）增宽或提前显影;牙根吸收者6例。M RI上Ⅰ类主要表现为不同程度流空效应,Ⅱ类主要表现为T1 WI等低信号,T2 WI高信号,增强后明显强化。结论增强CT扫描能显示颌骨AVM病灶范围及血管侵犯情况,可为首选检查。