Regression of nodular liver lesions in Wilson's disease.

Long-term follow-up abdominal imaging studies have not been reported previously in patients with the hepatic form of Wilson's disease (WD). This paper reports the case of a 35-year-old woman with symptoms dating back several months and with multiple, nodular liver lesions. The lesions were hyperdense on non-enhanced computed tomography and hypointense on T2-weighted magnetic resonance (MR) images. A diagnosis of WD was established several weeks after her admission to hospital, and chelating treatment was commenced promptly. No abnormalities were found on follow-up MR examinations of the abdomen and brain 4.5 years later. These imaging features suggest that so long as WD is diagnosed in the initial stages, liver nodules can regress with time and complete healing can be achieved with continuous decoppering treatment.

Brain magnetic resonance imaging in tyrosinemia.

A 3.5-year-old girl with tyrosinemia is reported. A computed tomography scan of the abdomen revealed multiple hepatic nodules. Brain magnetic resonance imaging revealed bilateral high-signal changes confined to the globus pallidus on T2-weighted images. Globus pallidus lesions likely represented neuropathologic changes such as astocytosis, delayed myelination, and status spongiosus (myelin splitting and vacuolation).

Walker-Warburg syndrome: diffusion MR imaging.

A 5-month-old boy with Walker-Warburg syndrome is reported. On MR imaging a characteristic pontomesencephalic kink was evident. Collicular fusion, hydrocephalus, callosal dysgenesis, cobblestone lissencephaly, small cerebellar cysts, pontine and cerebellar hypoplasia, and bilateral subretinal hemorrhages were noted. ADC (apparent diffusion coefficient) maps of an echoplanar diffusion MR imaging sequence revealed an elevated diffusion pattern throughout the cerebral white matter, manifested with prominently high ADC values, ranging from 1.82 to 2.45 x 10(-3) mm2/s. This corresponded to prominent hypomyelination. On the other hand, ADC values of the lissencephalic cortex were normal, ranging from 0.95 to 0.97 x 10(-3)mm2/s. In addition, ADC values from the hypoplastic cerebellar hemispheres, and from the hypoplastic pons were normal.

Diffusion magnetic resonance imaging patterns in metabolic and toxic brain disorders.

PURPOSE: To evaluate metabolic and toxic brain disorders that manifest with restricted, elevated, or both restricted and elevated diffusion patterns on diffusion magnetic resonance imaging (MRI). MATERIAL AND METHODS: Echo-planar diffusion MRI examinations were obtained in 34 pediatric patients with metabolic and toxic brain disorders proved by appropriate laboratory studies. The MRI unit operated at 1.5 T with a gradient strength of 30 mT/ meter, and a rise time of 600 micros. b=1000s/mm2 images and apparent diffusion coefficient (ADC) maps with ADC values were studied. RESULTS: Three patterns were observed: 1. A restricted diffusion pattern (high signal on b = 1000 s/mm2 images and low ADC values); 2. an elevated diffusion pattern (normal signal on b = 1000s/mm2 images and high ADC values); and 3. a mixed pattern (coexistent restricted and increased diffusion patterns in the same patient). Disorders manifesting with a restricted diffusion pattern included metachromatic leukodystrophy (n = 2), phenylketonuria (n = 3), maple syrup urine disease (intermediate form) (n = 1), infantile neuroaxonal dystrophy (n = 1), Leigh (n = 2), Wilson (n = 3), and Canavan disease (n = 1). Disorders with an elevated diffusion pattern included phenylketonuria (n = 1), adrenoleukodystrophy (n = 1), merosin-deficient congenital muscular dystrophy (n = 2), mucopolysaccharidosis (n = 2), Lowe syndrome (n = 1), Leigh (n = 2), Alexander (n = 1), Pelizaeus-Merzbacher (n = 1), and Wilson (n = 3) disease. Disorders with a mixed pattern included L-2 hydroxyglutaric aciduria (n = 2), non-ketotic hyperglycinemia (n = 1), infantile neuroaxonal dystrophy (n =2), maple syrup urine disease (n = 1), and Leigh (n = 1) disease. CONCLUSION: The findings suggested that the three different diffusion patterns reflect the histopathological changes associated with the disorders and different stages of a particular disorder. It is likely that the restricted diffusion pattern corresponds to abnormalities related to myelin, and the elevated diffusion pattern to disintegration of the tissue. The mixed pattern has contributions from both myelin abnormalities related to myelin disintegration of the tissue.

Epidermoid tumor of the pons.

Epidermoid tumors originating from the brainstem are extremely rare. The authors report a patient with an intraaxial epidermoid tumor of the pons. The tumor involved most of the pons and had a small exophytic component.

Lowe syndrome: proton mr spectroscopy, and diffusion mr imaging.

A 3-year-old boy with Lowe syndrome had bilateral periatrial hyperintense lesions intermixed with small cyst-like changes in the periatial regions of the deep white matter at MR imaging. Proton MR spectroscopy revealed prominent myoinositol peaks suggesting the presence of gliosis. b = 1000 s/mm2 images of diffusion MR imaging were negative for the periatrial lesions. ADC maps, however, revealed high ADC values (1.76, and 1.66 x 10(-3) mm2/s), compared to the normal brain parenchyma (0.81 x 10(-3) mm2/s). These diffusion MR imaging findings likely represented gliosis.

Dermoid tumor with involvement of the frontal lobes.

Intraparenchymal location of a dermoid tumor is extremely rare, and there are only four reports in the literature. This article presents a patient with a dermoid tumor with trilobulated components; an extra-axial component in the basal frontal/ethmoidal region, and two intra-axial components located in each frontal lobe. In addition, two small fat-density lesions anterior to the component in the left frontal lobe were present, probably due to partial intraparenchymal rupture of the tumor. The pathogenesis of intra-axial locations is still controversial, and this article proposes that in at least some cases intraparenchymal rupture of dermoids can cause intra-axial dermoids.

Role of the constructive interference in steady-state sequence in the classification of sacral meningeal cysts.

PURPOSE: To investigate the role of the CISS (constructive interference in steady state) sequence in sacral meningeal cysts. MATERIAL AND METHODS: Fourteen patients with sacral meningeal cysts were included. Conventional T1W and T2W sequences and the CISS sequence (TR/TE = 12.25/5.90) were obtained at 1.5-T. The 1-mm-thick base images and multiplanar reformatted images of the CISS sequence were studied. The sacral meningeal cysts were classified by the CISS sequence in accordance with the previously described surgical and histopathological criteria. RESULTS: A total of 25 sacral meningeal cysts were identified in the 14 patients. The cysts and their contents were visualized by the CISS sequence, and the CISS sequence was superior to the T1W and T2W images. Fifteen of the cysts were consistent with type I lesions (extradural meningeal cysts without nerve fibers inside) and 10 cysts with type II lesions (extradural meningeal cysts with nerve fibers inside). There were no type III lesions (intradural meningeal cysts) in the sacral region. CONCLUSION: Previous studies have indicated that conventional MRI as well as magnetic resonance myelography are inconsistent for a classification of sacral meningeal cysts. The CISS sequence with its capability to obtain T2W thin slice acquisitions is superior in showing the nerve root fibers contained in the cysts, which is essential in the differentiation of type I and II cysts. Application of the CISS sequence is recommended in the diagnosis of sacral meningeal cysts.

MR imaging of fetal abnormalities.

Our purpose was to evaluate the capability of ultrafast single-shot fast spin-echo MR imaging to assess normal fetal anatomy and abnormalities of different fetal organ systems. Fetal MR imaging was performed prospectively in consecutive 40 pregnant women because of abnormal findings or suspected fetal abnormalities on prenatal US. No statistically significant difference between US and MR imaging was found for the detection of abnormality in any organ system. MR imaging was slightly superior to US with regard to cerebral abnormalities only. In four (10%) of 40 fetuses, additional information provided by MR imaging altered counseling. However, MR imaging of the extremities-face and soft tissues was limited because of the lack of real-time information.

Pelizaeus-Merzbacher disease: diffusion MR imaging and proton MR spectroscopy findings.

A 5-Year-old boy is reported with genetically confirmed Pelizaeus-Merzbacher disease. On chemical-shift spectroscopic imaging choline (Cho) peaks were prominently decreased in the white matter resulting in markedly high NAA/Cho ratios, and low Cho/Cr ratios, compared to five control cases. Low Cho levels could be indicative of the dysmyelinating disorder in the disease. On b=1000 s/mm(2) images of diffusion MRI, a tigroid pattern was evident, and there was no apparent signal abnormality. However, on ADC maps high signal and high ADC values were evident in the white matter ranging from 1.16 to 1.52 X 10(-3) mm(2)/s, compared to the ADC values of nine control cases, consistent with some disintegration of the white matter secondary to lack of myelination. On the other hand, the ADC values of the cortex were normal (0.79-0.95 X 10(- 3) mm(2)/s). These findings on spectroscopy and diffusion MRI likely represented deficient myelination in the disease.

Diffusion MRI findings in neonatal brain abscess.

In neonates and infants, bacterial brain abscess is rare, and the diffusion weighted MR imaging appearance of such abscesses has not been reported. We report the diffusion weighted MR findings of a brain abscess in a 25-day-old boy. The lesion initially had a large cystic component with some high-signal pyogenic material inside on diffusion-weighted (b=1000 sec/mm(2))images. The ADC value of this material was low (0.59 x 10(-3) mm(2)/sec), compared to the value from normal cerebellar parenchyma (0.78 x 10(-3) mm(2)/sec). The unusual initial appearance mimicked a cystic tumor. The lesion markedly decreased in size over 20 days after antibiotic therapy with persistent high-signal pyogenic material. In addition, at the initial presentation b=1000 sec/mm(2) images revealed high-signal changes in the brain parenchyma compressed by markedly dilated ventricles, consistent with ischemia. Also, ADC values of perilesional vasogenic edema (1.74 x 10(-3) mm(2)/sec), and that of transependymal resorption of CSF (1.56 x 10(-3) mm(2)/sec) were noted at the initial stage.

Subacute sclerosing panencephalitis with pontine involvement.

In subacute sclerosing panencephalitis, brainstem involvement is rare. This paper reports an 11-year-old boy with the disease with prominent pontine involvement. Diffusion magnetic resonance imaging had superior information with respect to involvement of the nerve fibers. In the ventral part of the pons, the regions containing the longitudinal pontine nerve bundles were spared bilaterally and symmetrically. The pontine tegmentum was also spared. High signal in the affected regions was revealed by b = 1000 s/mm2 images. The apparent diffusion coefficient values in these regions were low, ranging between 0.43 x 10(-3) to 0.54 x 10(-3) mm2/s. Those of the spared tegmentum and longitudinal bundles were normal, ranging between 0.89 x 10(-3) to 1.04 x 10(-3) mm2/s, compared with the values from the normal-appearing regions of the cerebellar parenchyma.

Diffusion MRI in the postmortem brain: case report.

Postmortem brain of a ten-month-old child was examined by MR imaging, and diffusion MR imaging at the 12th hour after death in order to disclose the cause of death. There were basal ganglion lesions indicating a mitochondrial disorder. There was a prominent difference between the ADC values of the white matter (0.28+/-0.04 x 10(-3) mm2/s) and cortex (0.42+/-0.04 x 10(-3) mm2/s), and this was statistically significant (p< 0.0001). This difference suggested that in the postmortem brain the conditions in the white matter leading to restriction of movement of water molecules are more severe than that in the cortex.

Diffusion MRI and spectroscopy in Rasmussen's encephalitis.

The purpose of this study was to evaluate the diffusion MRI and proton MR spectroscopy findings in a rare disorder, Rasmussen's encephalitis. Diffusion MRI studies of 3 cases of Rasmussen's encephalitis were performed using the echo-planar trace sequence (TR=5700 ms, TE=139.03 ms). The gradient-echo diffusion sequence, PSIF (TR=21.6 ms, TE=5 ms), which is a reverse FISP sequence, and proton MR spectroscopy (TR=1500 ms, TE=40 ms) were applied in two patients. The trace sequence revealed high apparent diffusion coefficient values at the diseased regions (1.21+/-0.13 x 10(-3) mm2/s), compared with normal parenchymal values in 12 control cases (0.84+/-0.09 x 10(-3) mm2/s), indicating increased motion of water molecules (disintegration of the tissue) in these regions. The PSIF sequence revealed pixel value differences between the two hemispheres. Proton MR spectroscopy revealed decreased N-acetyl aspartate peaks, compared with five control cases.

Metachromatic leukodystrophy. Diffusion MR imaging and proton MR spectroscopy.

Metachromatic leukodystrophy is characterized by dysmyelination caused by a deficiency of arylsulfatase-A. In a 17-month-old boy with metachromatic leukodystrophy, an echo-planar diffusion MR sequence revealed a restricted diffusion pattern in the deep white matter, manifested by high-signal on b=1000 s/mm2 images, and low ADC values (0.56 x 10(-3) mm2/s). Proton MR spectroscopy revealed a marked decrease in choline, a metabolite related to myelin turnover. These observations consisting of a restricted diffusion pattern on diffusion MR imaging, and decreased choline peaks on proton spectroscopy, likely represented dysmyelination in metachromatic leukodystrophy.

Diffusion MR imaging of giant cell tumors in tuberous sclerosis.

Giant cell tumors were studied by diffusion MR imaging in three patients with tuberous sclerosis. Diffusion MR imaging was performed on a 1.5-T unit with a gradient strength of 30 mT/m. b = 1000 seconds/mm2 images, and apparent diffusion coefficient (ADC) maps were studied. ADC values were recorded from ADC maps with particular care to obtain the values from the noncalcified regions of the giant cell tumors. ADC values of the normal brain parenchyma and hamartomas were also recorded by multiple evaluations. The ADC values in all three giant cell tumors (0.78, 0.92, and 0.92 x 10-3mm2/s) were within the ranges of the normal brain parenchyma (0.62-1.04 x 10-3mm2/s), and they were prominently less than those of parenchymal hamartomas (1.18-1.86 x 10-3mm2/s). The finding of ADC values of the noncalcified portions of the giant cell tumors being identical to those of normal brain parenchyma is consistent with the presence of normal molecular motion of water, hence relatively normal tissue integrity within these tumors. This was likely a reflection of benignity of these slowly growing tumors.

Diffusion MR imaging changes associated with Wilson disease.

We herein report the case of a patient with Wilson disease. The patient underwent echo-planar diffusion MR imaging twice, 1.5 years apart. The lesions were in the putamina and caudate nuclei. At the first examination, undertaken after onset of extrapyramidal symptoms, a restricted diffusion pattern was evident. It is likely that this corresponded to cell swelling caused by the accumulation of copper. On the images obtained 1.5 years later, an opposite pattern (an elevated diffusion pattern) was noted. It is likely that this reflected necrosis, spongiform degeneration, and demyelination, which are among the known histopathologic changes associated with Wilson disease.

Rhombencephalosynapsis and a Chiari II malformation.

Rhombencephalosynapsis is an anomaly of the hindbrain characteristically presenting with cerebellar fusion and absence of cerebellar vermis on magnetic resonance imaging. Its association with spinal anomalies has not been reported previously. We report a unique case, a 22-year-old man with cerebellar fusion associated with a cervicothoracic meningomyelocele, diastematomyelia, tethering of the spinal cord, and dorsal dermal sinuses. In addition, cerebellar tonsillar herniation and tectal beaking similar to that seen in Chiari II malformations were present. These findings suggest that rhombencephalosynapsis can be associated with spinal malformations and, furthermore, that cases with the common features of rhombencephalosynapsis and a Chiari II malformation can exist. Such an association likely represents a new anomaly of the hindbrain and spine.