四氢生物蝶呤缺乏症患儿的头颅磁共振成像观察

目的应用磁共振成像技术观察四氢生物蝶呤(BH4)缺乏症患儿脑白质的改变，以了解BH4缺乏对脑髓鞘发育的影响，为判断治疗效果提供影像学根据。方法BH4缺乏症患儿11例，年龄17周至4岁，其中9例经新生儿筛查发现，虽然经过低苯丙氨酸(Phe)饮食治疗将血Phe浓度控制在120～240μmol／L范围内，患者仍出现进行性肌张力低下和智力发育落后。所有患者均经尿蝶呤谱分析、BH4口服负荷试验及红细胞二氢蝶呤还原酶测定，确诊为BH4缺乏症。患儿用0．5T超导型MR仪进行头颅扫描。结果11例患儿均存在髓鞘发育延迟，其中额叶11例，枕叶8例，颞叶4例，顶叶3例，胼胝体发育不良6例。全部病例在T2WI上脑白质内均有弥漫性高信号病灶。结论所有BH4缺乏症患者都存在脑白质病变，推测这种损害不仅可能与高Phe血症有关，且与神经递质的合成障碍有关。     

Cranial MR in phenylketonuria

Phenylketonuria (PKU) is an autosomal recessive disease in which defects in phenylalanine metabolism result in hyperphenylalaninemia. Untreated patients generally have poor motor function and are profoundly retarded. We report a patient with PKU whose cranial magnetic resonance abnormalities correlate with known histopathologic changes. The ability to image the pathologic changes in PKU may have important implications regarding treatment and prognosis of these patients.     

Novel proton MR spectroscopy findings in adenylosuccinate lyase deficiency

Adenylosuccinate lyase (ADSL) deficiency is a rare inborn error of metabolism resulting in accumulation of metabolites including succinylaminoimidazole carboxamide riboside (SAICAr) and succinyladenosine (S‐Ado) in the brain and other tissues. Patients with ADSL have progressive psychomotor retardation, neonatal seizures, global developmental delay, hypotonia, and autistic features, although variable clinical manifestations may make the initial diagnosis challenging. Two cases of the severe form of the disease are reported here: an 18‐month‐old boy with global developmental delay, intractable neonatal seizures, progressive cerebral atrophy, and marked hypomyelination, and a 3‐month‐old girl presenting with microcephaly, neonatal seizures, and marked psychomotor retardation. In both patients in vivo proton magnetic resonance spectroscopy (MRS) showed the presence of S‐Ado signal at 8.3 ppm, consistent with a prior report. Interestingly, SAICAr signal was also detectable at 7.5 ppm in affected white matter, which has not been reported in vivo before. A novel splice‐site mutation, c.IVS12 + 1/G > C, in the ADSL gene was identified in the second patient. Our findings confirm the utility of in vivo proton MRS in suggesting a specific diagnosis of ADSL deficiency, and also demonstrate an additional in vivo resonance (7.5 ppm) of SAICAr in the cases of severe disease. J. Magn. Reson. Imaging 2013;37:974–980. © 2012 Wiley Periodicals, Inc.     

Cranial MR imaging of osteopetrosis

BACKGROUND AND PURPOSE: The purpose of this study was to describe the cranial MR imaging manifestations of osteopetrosis. These features have not previously been reported in the literature. METHODS: Cranial MR studies, obtained with a uniform imaging protocol, were reviewed in 47 patients with osteopetrosis. Thirty-four patients had autosomal recessive (malignant) osteopetrosis (AROP), seven had intermediate osteopetrosis (IOP), and six had either type I or type II autosomal dominant osteopetrosis (ADOP I or II). The prevalence of abnormalities was tabulated and compared with the specific osteopetrosis variants. RESULTS: All patients with osteopetrosis had thickening and sclerosis of the calvaria. Ventriculomegaly, tonsillar herniation, proptosis, and dural venous sinus stenosis were observed in the majority of patients with AROP and ADOP I. Optic nerve sheath dilatation occurred in many of the patients with AROP and in all patients with ADOP I. Acquired cephaloceles were also observed only in these two groups. Optic nerve atrophy and optic canal stenosis were observed in a majority of patients with AROP, IOP, and ADOP II. Middle ear fluid was prevalent in AROP and IOP, present in over half the patients in each group. Features seen most prevalently, or exclusively, in AROP included stenosis of the internal carotid and vertebral arteries and extramedullary hematopoiesis. CONCLUSION: The cranial MR imaging features of osteopetrosis are both shared and unique among the various subtypes of the disease. The specific cranial and intracranial manifestations reflect the predominant calvarial or skull base patterns of bone thickening. The unique features seen in patients with AROP probably reflect the early age of onset and the greater severity of this form of the disease.     

Cranial MR imaging in neurofibromatosis

Cranial MR images of 53 patients with neurofibromatosis were reviewed to determine the nature, extent, and number of intracranial abnormalities present. All patients studied met tentative definitions established for the diagnosis of neurofibromatosis. Twenty-three were scanned for evaluation of known CNS of cranial nerve involvement; the remainder were neurologically asymptomatic patients without suspected lesions referred for screening. Single lesions were noted in 32 patients. Multiple lesions were identified in 14 patients. Seven had normal scans. In 23 patients small focal areas of increased signal on T2-weighted scans within the brain were though to represent heterotopias. Eight patients had chiasmal gliomas and two had optic nerve gliomas. Nine patients had parenchymal gliomas, two had ischemic changes, and one had a colloid cyst. Extraaxial lesions included acoustic neuromas (five patients), meningiomas (four), trigeminal neurofibromas (one), and dysplasia of a sphenoid wing (two). Of the 30 asymptomatic patients referred for screening, lesions were found in 23. MR was found to be an excellent method of imaging known disease and of detecting lesions in asymptomatic patients. Because of the large number of asymptomatic lesions detected in this population, a screening MR study is recommended in patients with neurofibromatosis.     

Congenital muscular dystrophy with merosin deficiency: 1H MR spectroscopy and diffusion-weighted MR imaging

PURPOSE: To prospectively use hydrogen 1 ((1)H) magnetic resonance (MR) spectroscopy and apparent diffusion coefficient (ADC) maps to try to explain the discrepancy between the extensive white matter (WM) abnormalities observed at MR imaging and the relatively mild neurocognitive decline in patients with merosin-deficient congenital muscular dystrophy (CMD). MATERIALS AND METHODS: The hospital ethics committee approved this study, and informed consent was obtained. Nine patients (five boys, four girls; age range, 3-9 years; mean, 6 years +/- 2 [standard deviation]) with merosin-deficient CMD underwent T1-weighted, T2-weighted, fluid-attenuated inversion recovery, and diffusion-weighted MR imaging and (1)H MR spectroscopy, which was performed in the parieto-occipital WM (POWM) and frontal WM (FWM) by using stimulated-echo acquisition mode. Metabolite (N-acetylaspartate [NAA], choline-containing compounds [Cho], and myo-inositol [mI]) ratios were calculated in relation to creatine/phosphocreatine (Cr) and water (H(2)O). NAA/Cho was also calculated. ADCs were calculated in approximately the same locations that were studied with spectroscopy. For comparison, (1)H MR spectroscopy (n = 10) and ADC mapping (n = 7) were also performed in 10 healthy age- and sex-matched control subjects (three boys, seven girls; age range, 4-9 years; mean, 6 years +/- 1). Statistical analysis involved the t test for comparison between different groups; correlation between ADC and spectroscopy results was studied with the Pearson test. RESULTS: MR imaging revealed evidence of bilateral WM involvement in all patients. Whereas their NAA/Cr and Cho/Cr were normal, their mI/Cr was slightly increased compared with that in control subjects (P = .03 in FWM and P = .07 in POWM), and their NAA/Cho was decreased in POWM (P = .03). NAA/H(2)O, Cr/H(2)O, Cho/H(2)O, and mI/H(2)O were considerably decreased (P < .05 for all) and ADC values were increased (P < .001) in WM in all patients versus these values in WM in control subjects. There was significant correlation between ADC values and metabolite/water ratios (r = -0.777 to -0.967, P < .05). CONCLUSION: ADC mapping and (1)H MR spectroscopy reveal abnormally high free-water concentrations in the WM of patients with merosin-deficient CMD.     

Wilson病脑MRI表现：附九例报告及文献复习

作者报告９例肝豆状核变性病人的脑磁共振扫描结果。发现不同部位出现不同程度的高低异常信号。结合文献及病理学理论对这些信号变化进行了分析。高信号的出现与胶质增生及局部水肿有关；而低信号与重金属铜及铁沉积有关。     

MR and proton MR spectroscopy of the brain in hyperhomocysteinemia caused by methylenetetrahydrofolate reductase deficiency.

MR imaging showed severe atrophy and large areas without myelination in the brain of a girl with methylenetetrahydrofolate reductase deficiency. Proton MR spectroscopy revealed mild signal reduction of N-acetylaspartate. After treatment with betaine, a second MR imaging study revealed a decrease in the size of the hypomyelinated zones that was paralleled by improved clinical status and laboratory findings.     

Cranial MR imaging in hypomelanosis of Ito

Hypomelanosis of Ito (HI) is a rare neurocutaneous syndrome frequently associated with neurologic abnormalities. Approximately 95 cases have been reported in the literature. Intracranial findings demonstrated by magnetic resonance imaging in a patient with HI include hemimegalencephaly, abnormal white matter signal, and small discrete bilateral periventricular cysts. No gray matter heterotopias or other migrational abnormalities were identified. Periventricular cystic lesions have not been described previously in this condition.     

In vivo pyruvate detected by MR spectroscopy in neonatal pyruvate dehydrogenase deficiency

We present a unique finding of an elevated level of pyruvate at 2.37 ppm revealed by in vivo MR spectroscopy of a female neonate. Low fibroblast pyruvate dehydrogenase (PDH) complex activity subsequently confirmed a diagnosis of PDH deficiency. Abnormalities of brain development consistent with PDH deficiency were also evident on fetal and postnatal MR images. To our knowledge, this is the first report of pyruvate being shown in vivo in a child and the first report of MR spectroscopy aiding in the diagnosis of inborn error in pyruvate metabolism before confirmation by conventional enzymatic testing. This finding has potential implications for earlier diagnosis in patients with defects in mitochondrial metabolism.     

Cranial postoperative site: MR imaging appearance

The ability to diagnose adverse postcraniotomy or postcraniectomy events is essential for proper postoperative care. The importance of identifying postoperative changes on CT has previously been shown. The purpose of this study is to assess the normal and abnormal MR changes that may be seen in the postcraniotomy/postcraniectomy period. The postoperative MR, CT, and medical records of 41 postcraniotomy patients and 26 postcraniectomy patients were reviewed. Reasons for choosing craniectomy over craniotomy included decompression, infected flap, bony involvement by tumor, and posttraumatic skull. In general, the postoperative normal anatomy was better seen with MR. Postoperative events included hemorrhage (two), infection (five), cyst formation (10), and recurrent tumor (five). In general, MR was found to be more useful than CT for the detection of hemorrhage and infection after craniotomy or craniectomy and for the proper localization of postoperative cysts. MR proved to be a useful method for following postoperative sites in the skull.     

Cranial MR imaging of sequelae of prefrontal lobotomy

BACKGROUND AND PURPOSE: Although prefrontal lobotomy is an obsolete treatment for schizophrenia, we still encounter patients who have undergone this procedure. The purpose of this study was to describe the MR imaging findings of sequelae of prefrontal lobotomy. METHODS: We retrospectively reviewed cranial MR images of eight patients with schizophrenia who underwent prefrontal lobotomy approximately 50 years previously. RESULTS: In all patients, a bilateral cavitary lesion with a thick wall was found in the frontal white matter. The genu of the corpus callosum was mildly to markedly atrophic. The size and location of the cavity and the degree of callosal atrophy were correlated. CONCLUSION: MR imaging is useful for the diagnosis of sequelae of prefrontal lobotomy, including cavitary lesions with dense walls of gliosis and secondary degeneration of the genu of the corpus callosum.     

Cranial MR imaging findings of potassium chlorate intoxication

We present the case of a patient who attempted suicide by ingesting matchstick heads (55% potassium chlorate). The patient presented to the emergency room with loss of consciousness, and MR imaging revealed symmetric hyperintense signal within the deep gray matter and medial temporal lobes. The patient improved after undergoing conventional treatment and hyperbaric oxygen.     

Cranial MRI and MR angiography in Menkes' syndrome

We report two boys with Menkes' syndrome who underwent cranial MRI and MR angiography (MRA). In both, CT and MRI revealed progressive cerebral atrophy with a subdural haematoma or effusion. Delayed myelination or dysmyelination of the white matter was suggested. Tortuosity of the cervical and intracranial vessels was well demonstrated by MRA, obviating more invasive conventional angiography should it be thought necessary to demonstrate the characteristic systemic vascular changes of this syndrome.     

Cranial CT and MR in the Klippel-Trenaunay-Weber syndrome.

This report describes the intracranial CT and MR findings in two cases of Klippel-Trenaunay-Weber Syndrome. The findings are 1) markedly enhancing choroid plexuses, 2) severe cerebral atrophy, 3) cerebral calcifications, and 4) angiomatous leptomeningeal enhancement. The findings may resemble those seen in cases of bilateral Sturge-Weber syndrome. The two diseases should be distinguishable by the external stigmata. The authors raise the question of a spectrum of involvement in the angiodysplasias of Klippel-Trenaunay-Weber syndrome and Sturge-Weber syndrome with considerable overlap.     

MR spectroscopy in schizophrenia

The purpose of this study is to review the MR spectroscopic literature regarding schizophrenia. However, as there are over 250 primary MRS articles and dozens of MRS review articles on the subject already, this study will take a different approach. First, the clinical features of schizophrenia will be described. The background neuroanatomy and biochemistry relevant to schizophrenia will be reviewed, as many readers of this journal are unlikely to be familiar with these fields. A current model of the abnormal neural circuitry in schizophrenia will be presented, and predictions extrapolated about relevant metabolite changes over time. Finally, the existing MRS literature will be reviewed in the context of our existing anatomical and chemical knowledge, and future MRS research directions will be elaborated.     

Cranial MR findings in chronic toluene abuse by inhalation

BACKGROUND AND PURPOSE: Chronic abuse of toluene by inhalation causes variable white matter changes and thalamic hypointensity on T2-weighted MR images. The purpose of our study was to assess cranial MR findings in a large series of patients who chronically abuse toluene-containing solvents to investigate the factors causing the qualitative variability of white matter changes and thalamic hypointensity. METHODS: We studied the neurologic signs, symptoms, and cranial MR findings in 41 patients who chronically abused thinner, a toluene-containing solvent. We classified white matter changes as diffuse or restricted. We tested the associations of the development of white matter lesions and thalamic hypointensity with patient age at onset of abuse and duration of abuse. RESULTS: MR images revealed white matter lesions in 46% of the patients, atrophic dilatation of ventricles and sulci in 27%, and thalamic hypointensity in 20%. White matter changes were restricted in 53% and diffuse in 47%. The development of white matter changes and thalamic hypointensity were significantly associated with duration of abuse longer than 4 years (P <.05 and P <.01, respectively). CONCLUSION: White matter changes seem to start in the deep periventricular white matter, and they spread into peripheral white matter, causing the loss of gray matter-white matter differentiation with continued toluene abuse. The deposition of iron due to demyelination and axonal loss is the most probable mechanism for the thalamic hypointensity found in solvent abusers.     

Cranial postoperative site: assessment with contrast-enhanced MR imaging

To define duration and patterns of postoperative contrast material enhancement, the authors evaluated magnetic resonance (MR) images obtained with gadolinium diethylenetriaminepentaacetic acid (DTPA) in 46 patients who had undergone major intracranial surgery. Intervals between surgery and MR imaging ranged from 1 day to 40 years (median, 1.3 years). Moderate or marked brain and dural enhancement was noted in nearly every patient imaged within 3 months of surgery, but all brain enhancement was gone by 1 year. Abnormal dural enhancement was noted in every patient imaged within 1 year of surgery and in approximately 50% at 1-2 years afterward. One patient had persistent mild enhancement of the dura 40 years after surgery. MR images revealed enhancement in several sites not frequently recognized on computed tomographic (CT) scans. Brain and meningeal enhancement with Gd-DTPA at cranial operative sites was more extensive and persisted much longer than is commonly seen on contrast-enhanced CT scans. Enhancement of the brain or pia mater does not normally last beyond 1 year, but dural enhancement may persist for decades.