Diffusion MR imaging features of skull base osteomyelitis compared with skull base malignancy.

BACKGROUND AND PURPOSE: SBO is a life-threatening infection that may have radiologic features similar to those of the neoplastic processes. The purpose of this study was to evaluate the DWI findings in SBO to facilitate the differential diagnosis. MATERIALS AND METHODS: The MR imaging findings of 9 patients with SBO were retrospectively evaluated and compared with MR imaging studies from 9 patients with NPC, 9 with lymphoma, and 9 with metastatic disease of the skull base. ADC measurements were performed from the ADC(ST) and the ADC(NST) in all 4 groups. RESULTS: The mean ADC(ST) values were 1.26 ± 0.19 × 10(-3) mm(2)/s for SBO, 0.74 ± 0.18 × 10(-3) mm(2)/s for NPC, 0.59 ± 0.11 × 10(-3) mm(2)/s for lymphoma, and 0.99 ± 0.34 × 10(-3) mm(2)/s for metastatic disease, respectively. The mean ADC value of SBO was significantly higher than those of NPC and lymphoma (P < .0001). There was no significant difference for the comparison of SBO and metastatic lesions. When an ADC value equal to or higher than 1.08 × 10(-3) mm(2)/s was used to rule out lymphoma and NPC, the accuracy was 96%. CONCLUSIONS: Although SBO is a relatively rare condition, its differential diagnosis from neoplastic processes of the skull base is essential to start appropriate treatment promptly. ADC values may help to distinguish patients with SBO from those with malignant lesions.

An extreme lateral lumbar disc herniation mimicking L4 schwannoma.

OBJECTIVE: We herein describe a case with an extraspinal mass distorting the right L4 dorsal root ganglion. Initially presumed to be a nerve root schwannoma, the lesion turned out to be a free disc fragment. METHODS AND RESULTS: A 46-year-old woman presented with a history of mild low back and intense right leg pain. The leg pain was like electrical discharges. Right knee extension was weak together with hyperalgesia and loss of heat sensation in the right LA dermatome. The right patellar reflex was absent. Electromyography showed acute and chronic denervation of muscles innervated by the right L4 nerve root. MR scan showed a right L4-5 extraforaminal mass distorting the L4 dorsal root ganglion. The mass enhanced homogeneously after gadolinium injection and was thought to be a tumor. It was surgically removed using a midline incision and intraspinal, followed by extraspinal dissection. Under the operating microscope, the mass extended between an intact lateral longitudinal ligament and a swollen dorsal root ganglion. Histopathologic examination ruled out a tumor and showed that the mass consisted of degenerated disc material surrounded by a large peripheral zone of neovascularization. CONCLUSION: Extraforaminal periganglionic free, encapsulated disc fragments may mimic tumoral masses, from which they may not be distinguished on MRI.

Fusiform basilar artery aneurysm rapid death with occlusion and subdural-subarachnoid hemorrhage.

Fusiform aneurysms of the posterior circulation constitute a relatively uncommon subgroup of aneurysms. We present a patient with fusiform basilar artery aneurysm accompanied by ectasia and elongation of both supraclinoid parts of the internal carotid arteries, middle cerebral arteries and vertebral arteries. The aneurysm had thrombus formation along its length which progressed to occlude the lumen the day after the patient's admission. Mass effect, progressive infarcts at the territories of posterior inferior cerebellar (PICA) and superior cerebellar (SCA) arteries and brainstem perforators along with subarachnoid and subdural hemorrhage were present.

Diffusion-weighted MR imaging and MR spectroscopy in glutaric aciduria type 1.

Although conventional magnetic resonance imaging (MRI) findings of glutaric aciduria type 1 (GA-1) have been well established, diffusion weighted MR imaging (DWI) and proton MR spectroscopy (MRS) findings are limited. We report widespread restricted diffusion in the white matter and increased diffusion in bilateral putamen in a case of GA-1. The MRS showed decreased N-acetyl-aspartate (NAA)/creatine (Cr) ratio compared with a sex and age-matched control with no significant change in choline (Cho)/Cr ratio. The presence of the lactate peak reflecting disturbed mitochondrial functions in this disease has never been reported.

Diffusion-weighted imaging findings in juvenile metachromatic leukodystrophy.

Magnetic resonance (MR) imaging has an important role in the diagnosis of metachromatic leukodystrophy (MLD). We report diffusion-weighted MR imaging (DWI) findings of four cases of juvenile type MLD. DWI showed restricted diffusion lines with greater areas of increased diffusion in three patients and widespread increased diffusion in one patient. This variability in DWI findings can be related to the histological stage of the disease at the time of imaging, ranging from intracellular metachromatic material accumulation to breakdown of myelin membranes.

Magnetic resonance imaging findings in Kimura's disease.

Although early diagnosis of Kimura's disease, a rare chronic inflammatory disorder most commonly presenting with asymmetric swelling in the head and neck region, is helpful in avoiding unnecessary diagnostic tests and starting prompt treatment, only a few reports emphasized radiological findings in detail. Magnetic resonance imaging findings showing the infiltrative nature of the disease and diffuse loss of fat tissue even in nonpalpable normally appearing regions of the head and neck in a young man with Kimura's disease are presented in this report.

Rim enhancement of meningiomas on fast FLAIR imaging.

We investigated the enhancement patterns of meningiomas on fast fluid-attenuated inversion-recovery (FLAIR) images and related them to the size and histology of the tumour and the associated oedema. We studied 30 meningiomas with T2-weighted fast spin-echo (SE) images plus T1-weighted SE images with magnetisation-transfer saturation and fast FLAIR before and after contrast enhancement at 0.5 tesla. There were 21 meningiomas (70%) which showed peripheral (rim) enhancement on fast FLAIR, while only one, which showed heavy central calcification, enhanced peripherally on the SE images. Of the meningiomas with capsular enhancement on fast FLAIR 20 (95%) were more than 2 cm in diameter. The nine 9 smaller meningiomas enhanced homogeneously. This difference was statistically significant pattern ( P<0.01). All meningiomas which had associated oedema showed the capsular pattern although their number (6; 20%) was to small to analyse statistically. Only 11 (36%) tumours were examined histologically; peripheral enhancement was observed in all types of meningioma. This pattern may help to differentiate meningiomas from other extra-axial masses.

Does transverse apex coincide with coronal apex levels (regional or global) in adolescent idiopathic scoliosis?

STUDY DESIGN: Cross-sectional. OBJECTIVES: To identify the regional and global apexes of curves in adolescent idiopathic scoliosis and to compare the levels of those with the most rotated vertebral levels on computed tomography scans. SUMMARY OF BACKGROUND DATA: The terminology regarding the terms and definitions had been arbitrary until being refined and standardized by the Scoliosis Research Society Working Group on Three-Dimensional Terminology of Spinal Deformity. Apical vertebra or disc is defined as the most laterally deviated vertebra or disc in a scoliosis curve, but the most rotated vertebra (or disc) has not been included in this terminology. One study suggested that the most rotated vertebral level was always located at the apex. METHODS: Thirty-three structural curves of 25 consecutive patients scheduled for surgery for thoracic or thoracolumbar scoliosis were analyzed with standing anteroposterior radiographs and computed tomography scans covering the curve apexes and pelvis. Thoracic and lumbar curves were evaluated separately for all Type II curves. Vertebral rotations were normalized by the rotation of the pelvis. The most rotated vertebral (or disc) levels (transverse apex) were compared with the regional and global apex levels (vertebra or disc) (coronal apexes) of the corresponding curves separately. RESULTS: Regional and global apexes were at the same level in 18 (54.5%) curves, and within half a level in another 15 (45.4%), and the regional apex was one level higher in two curves (95% confidence levels: -0.82, +0.88). Comparison of the most rotated levels with regional and global apex levels revealed a higher variability, extending up to two levels for the global apex (95% confidence levels: -1.19, +1.54 levels for the global and -1.0, +1.41 levels for the regional apexes). CONCLUSION: This study demonstrated that the regional or global apex of a given curve is the most rotated level in only a minority of the curves. The most rotated level may be as far as two levels from the global apex and one level from the regional apex.

Measurement of vertebral rotation in standing versus supine position in adolescent idiopathic scoliosis.

Thirty-three structural curves of 25 patients with adolescent idiopathic scoliosis were evaluated using computed tomography (CT) scans and plain radiography. The average Cobb angle on standing radiographs was 55.72 degrees and was observed to be corrected spontaneously to 39.42 degrees while the patients were in supine position (29.78% correction). Average apical rotation according to Perdriolle was 22.75 degrees on standing radiographs and 16.78 degrees on supine scanograms. The average rotation according to Aaro and Dahlborn on CT scans was 16.48 degrees. Radiographic measurements were significantly different from axial CT slice or scanogram measurements (p = 0.000), but the two latter measurements, both obtained in the supine position, did not appear to be different (p = 0.495). Deformities on the transverse plane as well as on the coronal plane are influenced by patient positioning. If the patient lies supine, the scoliosis curve corrects spontaneously to some degree on both planes. Measurements obtained from the scanograms by the Perdriolle method in the supine position are very similar to those obtained by CT. Perdriolle's is a simple, convenient, and reliable method to measure rotation on standing radiograms.

Fusiform aneurysms detected 5 years after removal of an atrial myxoma.

Neurological signs frequently accompany atrial myxomas. Association of multiple cerebral aneurysms in patients with atrial myxomas are less common than embolic infarctions. The development of aneurysms years after the cardiac tumor removal is rare, and few MR images have been reported to date. A case of multiple peripheral fusiform aneurysms detected 5 years after tumor resection is presented in this report, together with MR images and CT and angiographic images.

Pleuropulmonary blastoma in a child presenting with pneumothorax.

Pleuropulmonary blastoma is an uncommon primary malignant tumor of the lung. Surgery is the most important part of the treatment. Despite the use of chemotherapy with or without radiotherapy, the prognosis is poor. Here we report on the case of a 2.5 year-old boy presenting with pneumothorax who turned out to have a right hemithoracic mass. The patient underwent surgical resection of the mass. Pathologic diagnosis was type II pleuropulmonary blastoma. Postoperative thoracic CT showed nodular residual densities so the patient was given adjuvant combination chemotherapy with cisplatin and etoposide. He has been disease free for 12 months.

Merosin-deficient congenital muscular dystrophy with mental retardation and cerebellar cysts unlinked to the LAMA2, FCMD and MEB loci.

We report a case of congenital muscular dystrophy with secondary merosin deficiency, structural involvement of the central nervous system and mental retardation in an 8-year-old girl from a consanguineous family. She had early-onset hypotonia, generalized muscle wasting, with weakness especially of the neck muscles, joint contractures, mental retardation and high creatine kinase. Muscle biopsy showed dystrophic changes with partial deficiency of the laminin alpha(2) chain. Cranial magnetic resonance imaging revealed multiple small cysts in the cerebellum, without cerebral cortical dysplasia or white matter changes. The laminin alpha(2) chain (6q2), Fukuyama type congenital muscular dystrophy (9q31-q33) and muscle-eye-brain disease (1p32-p34) loci were all excluded by linkage analysis. We suggest that this case represents a new entity in the nosology of congenital muscular dystrophy.

Riedel's thyroiditis in multifocal fibrosclerosis: CT and MR imaging findings.

Riedel's thyroiditis is a rare disorder of unknown etiology and may be seen isolated or as a part of multifocal fibrosclerosis. It is important to distinguish Riedel's thyroiditis from thyroid carcinoma. Reports about imaging features of Riedel's thyroiditis are limited in the radiologic literature. We describe herein CT and MR imaging features of Riedel's thyroiditis in a case of multifocal fibrosclerosis with previously unreported radiologic observations.

Magnetic resonance imaging in growth hormone deficiency: relationship between endocrine function and morphological findings.

Magnetic resonance imaging (MRI) using gadopentetate dimeglumine (Gd-DTPA) improves the delineation of hypothalamic-pituitary structures and facilitates the detection of anatomical abnormalities which are indicators of permanent growth hormone deficiency (GHD). The aim of this study was to determine the frequency of neuroradiological abnormalities in 85 (52 M, 33 F) patients with hereditary or idiopathic forms of isolated GHD (IGHD) or multiple pituitary hormone deficiency (MPHD) and also to investigate the relationship between anatomical findings and hormonal status. Pituitary hypoplasia with absent or thin infundibulum and ectopic posterior pituitary (EPP) were the most frequent findings in 39 patients with MPHD, whereas in 46 patients with IGHD the most frequent finding was pituitary hypoplasia without neuroradiological abnormalities. All patients whose infundibulum was not visualized after Gd-DTPA injection belonged to the MPHD group; therefore, absence of pituitary stalk can be a good indicator of the severity of hormonal deficiencies. Pituitary hypoplasia was found in all patients with familial IGHD. Among patients with abnormalities of the hypothalamic pituitary area on MRI, normal or breech delivery frequency distributed equally. Therefore it seems that mechanical or hypoxic prenatal events cannot be the primary etiological factor in all patients with neuroradiological abnormalities since half of these patients had normal delivery and birth history. The localization of the bright spot of the posterior pituitary at the level of the median eminence, midstalk position or at the end of the infundibulum may suggest a neuronal migration defect which may occur during early embryogenesis. In conclusion, in children with GHD a careful examination of the hypothalamic pituitary area by MRI after enhancement helps to establish the diagnosis and predicts the prognosis.

Evaluation of velopharyngeal insufficiency with magnetic resonance imaging and nasoendoscopy.

Several radiological methods have been utilized to assess velopharyngeal function. The more recent imaging technique, magnetic resonance imaging (MRI), which has a number of advantages over radiographic and computed tomographic imaging, has been used rarely for evaluating velopharyngeal insufficiency. In this study, 5 normal volunteers and 10 patients with surgically repaired cleft palate were examined with MRI using midsagittal, coronal, and axial images. Nasoendoscopy was also performed to complete and confirm the diagnoses. Complete and tight closure of the velopharynx and full backward and upward movement of the soft palate was observed in volunteers. In coronal images, medial movement of lateral pharyngeal walls could also be seen. Despite this, patients with surgically repaired cleft palate had some degree of motion of the soft palate, ranging from no movement to maximal movement. In most of the patients, short soft palates with restricted motion was seen. MRI visualizes the velopharyngeal sphincter in all planes and provides high-resolution images of the soft tissues. Objective measurements can be made as well. In this study, MRI and nasoendoscopy were used together in the diagnosis of velopharyngeal insufficiency and gave satisfactory results.