MRI of five patients with mitochondrial neurogastrointestinal encephalomyopathy

OBJECTIVE: The purpose of this study was to retrospectively review MR images of the brain in five patients diagnosed with mitochondrial neurogastrointestinal encephalomyopathy. CONCLUSION: Our research supports previously reported findings of confluent abnormal cerebral white matter in patients with mitochondrial neurogastrointestinal encephalomyopathy. In contrast to prior studies, our cohort of five patients showed that involvement of the corpus callosum as well as the capsular white matter, basal ganglia, thalami, midbrain, pons, and cerebellar white matter is not rare and does not preclude the diagnosis of mitochondrial neurogastrointestinal encephalomyopathy.     

儿童线粒体脑肌病的MRI表现

目的回顾性研究20例线粒体脑肌病患儿(年龄10个月到14岁)的MRI表现.方法20例由肌肉活检及实验室检查证实为线粒体脑肌病的患儿,脑内均有MRI阳性表现,研究其MRI表现的类型.结果20例患儿脑内病灶均表现为T1WI低、T2WI高信号,8例有不同程度的脑萎缩.18例患儿主要为灰质受累,其中10例为只有深部灰质病变;4例为深部灰质和大脑皮质同时受累.4例为深部灰质病变合并脑梗塞而同时累及灰质和白质.2例主要为白质受累,表现侧脑室后角旁白质异常信号.结论儿童线粒体脑肌病的MRI表现是多样性的.当儿童脑MRI表现为灰质(尤其是深部灰质)异常信号、灰质萎缩、不典型梗塞、不典型白质病变且合并临床难以解释的神经、肌肉等多系统的症状时,应考虑到线粒体肌病的可能.     

Positron emission tomography using pyruvate-l-11C in two cases of mytochondrial encephalomyopathy

Positron emission tomography (PET) using pyruvate-1-11C was carried out to investigate the in vivo metabolism of pyruvate in the brains of patients with mitochondrial encephalomyopathy and Leigh's disease. Two epileptic patients were studied as control subjects. Radioactivity was eliminated from the brain tissue of the epileptic patients soon after injection of pyruvate-1-11C. PET images of mitochondrial encephalomyopathy patients showed an increase in radioactivity in the cerebral cortex, basal ganglia and thalamus, with elimination of radioactivity being slower than that of epileptic patients. One patient with Leigh's disease showed similar PET images. PET using pyruvate-1-11C is useful for the evaluation of mitochondrial energy metabolism in the brain.     

线粒体脑肌病的MR诊断价值

目的探讨MR对线粒体脑肌病的诊断价值。方法回顾分析6例经临床和病理证实的线粒体脑肌病患者的MR表现。结果6例线粒体脑肌病的脑部病灶均表现为长T1长T2信号,病变主要累及颞叶、顶枕叶灰白质,甚至基底节区、脑干,大部分呈对称分布,呈多发性,游走性,与血管支配区分布不一致,还可见基底节钙化和脑萎缩。DWI显示病变多表现为ADC值升高。结论线粒体脑肌病的脑部MR表现具有一定的特征性,MR检查对线粒体脑肌病的诊断具有重要提示价值,结合肌肉活检可明确该病的诊断。     

Cerebral oxygen and glucose metabolism and blood flow in mitochondrial encephalomyopathy: a PET study

Cerebral blood flow (CBF), oxygen metabolism (CMRO₂), and glucose metabolism (CMRGlc) were measure using positron emission tomography in five patients diagnosed as having mitochondrial encephalomyopathy. The molar ratio between the oxygen and glucose consumptions was reduced diffusely, as CMRO₂ was markedly decreased and CMRGlc was slightly reduced. The CBF showed less changes. The CBF increase on hypercapnia was smaller than normal, though this was not significant. CBF with hypocapnia demonstrated a significant reduction compared with the normal. These results suggest that oxidative metabolism is imparied and anaerobic glycolysis relatively stimulated, due to a primary defect of mitochondrial function, and that mild lactic acidosis occurs in brain tissue because of impaired utilisation of pyruvate in the TCA cycle. As these findings appear to indicate directly a characteristic of this disease, such measurements may be a useful tool for assessment of the pathophysiology and for diagnosis of mitochondrial encephalomyopathy.     

Quantitative assessment of the total myocardial uptake ratio of 123I-BMIPP by using the Ishii-MacIntyre method is useful for predicting cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy

We evaluated the usefulness of the total myocardial uptake ratio (TMUR) of 15-(p-[123I]iodophenyl)-3(R,S)-methyl-pentadecanoic acid (123I-BMIPP) for predicting cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy. Six patients with mitochondrial encephalomyopathy, four with myotonic dystrophy, and 10 control subjects were studied. Quantitative assessment of 123I-BMIPP dynamic myocardial imaging was performed, and the TMUR of 123I-BMIPP was calculated according to the Ishii-MacIntyre method. Then, the TMUR was compared in the 10 patients and 10 healthy controls, and all patients were followed for 56.1+/-22.1 months to evaluate cardiac complications. TMUR in patients (2.69+/-0.64) was significantly (P =0.01) lower than that in controls (3.28+/-0.25). Three patients in whom the TMUR value was above 3.00 had no cardiac complications. On the other hand, all patients in whom TMUR was below 3.00 had some kind of cardiac complication during the follow-up period. Two patients showed progressive conduction abnormality and underwent pacemaker implantation, one patient had sick sinus syndrome and underwent pacemaker implantation, another patient showed non-sustained ventricular tachycardia and paroxysmal atrial fibrillation, and four of seven patients, including one with a pacemaker, showed an increased cardiothoracic ratio value over 50%. In conclusion, measurement of the TMUR by the Ishii-MacIntyre method is useful for evaluating the development of cardiac complications in patients with mitochondrial encephalomyopathy or myotonic dystrophy.     

Predominant cerebellar volume loss as a neuroradiologic feature of pediatric respiratory chain defects

BACKGROUND AND PURPOSE: Predominant cerebellar involvement has not been previously reported as a common neuroradiologic feature in pediatric mitochondrial cytopathies. Here we report the neuroradiologic findings of predominant cerebellar volume loss in children with various mitochondrial disorders. METHODS: A retrospective analysis of the medical records of 400 consecutive patients referred for evaluation of mitochondrial encephalomyopathies was performed. In 113 cases, definite diagnosis of mitochondrial disease was based on the modified adult criteria that include clinical, histologic, biochemical, functional, molecular, and metabolic parameters. RESULTS: Predominant cerebellar volume loss with progressive cerebellar atrophy and, less often, cerebellar hypoplasia were found in a heterogeneous group of patients with mitochondrial disease that consisted of four patients with complex I deficiency; four patients with multiple respiratory chain deficiencies; two patients with combined complex I + III and II + III deficiencies, including one patient with partial coenzyme Q10 deficiency; three patients with complex II deficiency; two patients with complex IV deficiency; one patient with mitochondrial neurogastrointestinal encephalomyopathy; and two patients with mitochondrial encephalomyopathy, lactic acidosis, and strokes. CONCLUSION: Our retrospective study shows that isolated or predominant cerebellar involvement can be found in various respiratory chain defects or mitochondrial disorders expanding the classical neuroradiologic findings observed in mitochondrial encephalomyopathies. The diagnostic workup in patients with neuromuscular features whose brain MR imaging exhibits cerebellar volume loss should include the evaluation for mitochondrial encephalomyopathies.     

HMPAO-SPECT imaging resembling Alzheimer-type dementia in mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS)

Single-photon emission computed tomography (SPECT) of the brain using hexamethyl propylene amine oxime (HMPAO) was performed in a 37-year-old patient suffering from mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS). Reduced blood flow was observed bilaterally in the parieto-occipital regions (resembling Alzheimer type dementia) and in the right parietal lobe.     

儿童线粒体脑肌病的脑部MRI表现与诊断

目的探讨儿童线粒体脑肌病的脑部MRI表现及其诊断价值。方法搜集1996年1月至2002年12月经病理与实验室检查证实的16例儿童线粒体脑肌病及其脑部MRI表现，并进行回顾性分析。结果16例患儿脑MRI均有多发对称性片状略长T1和长T2异常信号，其中单纯脑深部灰质受累9例，大脑皮质和深部灰质同时受累6例，单纯白质受累l例。临床主要表现为进行性智力减退(12例)和肌力减退(10例)。骨骼肌活检病理检查可见破碎样红纤维及异常线粒体。结论进行性智力和肌力减退是儿童线粒体脑肌病最常见的临床表现；脑深部灰质多发对称性斑片状异常信号是儿童线粒体脑肌病脑部MRI的主要表现；脑MRI是诊断儿童线粒体脑肌病的重要手段，但儿童线粒体脑肌病的确诊有赖于肌肉活检和基因检查。     

MRI在小儿线粒体脑肌病中的诊断价值

目的　探讨MRI在小儿线粒体脑肌病中的诊断价值。方法　搜集自 1996 -0 1～ 2 0 0 0 -12经MRI检查、病理及实验室检查证实的小儿线粒体脑肌病 16例进行回顾性分析。结果　 16例患者脑内病灶均表现为多发对称性略长T1、长T2 信号 ,其中单纯脑深部灰质受累 9例 ,大脑皮质和深部灰质同时受累 4例 ,灰、白质同时受累 2例 ,单纯白质受累 1例。结论　多样化的临床和MRI表现是小儿线粒体脑肌病的特点 ;MRI对小儿线粒体脑肌病的诊断有较大帮助。