Search

Adult T-cell leukaemia (ATL) is a T-cell lymphoid neoplasm caused by human T-cell leukaemia virus type I (HTLV-I). Radiological findings in central nervous system (CNS) involvement have not been well characterised. We reviewed the MRI of 18 patients with ATL who developed new neurological symptoms or signs, and pathology specimens from a 53-year-old woman who died of ATL. MRI findings were divided into three categories: definite, probable, and other abnormal. Definite and probable findings were defined as ATL-related. The characteristic findings were multiple parenchymal masses with or without contrast enhancement adjacent to cerebrospinal fluid (CSF) spaced and the deep grey matter of both cerebral hemispheres, plus leptomeningeal lesion. One patient had both cerebral and spinal cord lesions. Other abnormal findings in eight patients included one case of leukoencephalopathy caused by methotrexate. The histology findings consisted of clusters of tumour cells along perivascular spaces, and scattered infiltration of the parenchyma, with nests of tumour cells. Leptomeningeal infiltration by tumour spread into the parenchyma and secondary degeneration of the neuronal tracts was observed. MRI was useful for detecting CNS invasion by ATL and differentiating it from other abnormalities. The MRI findings seemed to correlate well with the histological changes.

Our purpose was to evaluate and compare the performance of ultra-fast single-shot T2-weighted sequences: echo-planar imaging (EPI) versus half-Fourier single-shot turbo spin-echo (HASTE) and to assess the usefulness of their combined reading. Comparative experiments on a phantom as well as a prospective clinical study in 47 patients were done. Axial images acquired with the following methods were compared: (a) HASTE; (b) segmented HASTE (s-HASTE); (c) single-shot spin-echo EPI (SE-EPI); and (d) gradient-echo EPI (GREEPI). Quantitative and qualitative criteria as well as lesion detectability were analyzed against the "gold standard" fast spin-echo (FSE) sequence. For contrast and contrast-to-noise ratio (CNR) between gray and white matter, GRE-EPI was best. The visibility of small markedly hyperintense lesion was best with HASTE and s-HASTE in the clinical study. Small hyperintense lesions were detected equally well with all four sequences, although all performed significantly worse than FSE. The two HASTE variants were better than the EPIs for the extraaxial lesions. The combination of the GRE-EPI and s-HASTE was judged best, and sometimes superior to the FSE image. HASTE or EPI alone cannot substitute for FSE in the screening evaluation of the brain. However, together, EPI and HASTE could provide comparable diagnostic information to that of FSE because their combination compensates for their individual limitations.

This work investigated whether turbo magnetic resonance angiography (MRA) can replace conventional MRA in screening examination of intracranial arteries. A phantom was used to evaluate the effect of the zero-filling interpolation (ZFI) technique on spatial resolution and partial volume effect. Thirty-one consecutive patients underwent both turbo MRA with a slice thickness of 0.7 mm (data were measured as 1.33 mm sections) and conventional MRA with 1.0 mm sections. In the phantom studies, ZFI did not improve the spatial resolution, but the partial volume effect was somewhat reduced. In the clinical evaluation, turbo MRA showed better signal-to-noise and contrast-to-noise ratios of the intracranial major vessels than conventional MRA. The lesions included cerebral aneurysms less than 3 mm in diameter, occlusive vascular disease, arteriovenous malformations, and arteriovenous fistulas. These were all depicted on both turbo MRA and conventional MRA. Turbo MRA is a useful screening procedure because of its capability of delineating lesions in approximately half the usual imaging time. J. Magn. Reson. Imaging 1999;10:939-944.

Purpose The purpose of this work was to assess the changes of signal intensity on constructive interference in steady state (CISS) 3D Fourier transformation (3DFT) MRI after administration of Gd-DTPA and to evaluate the efficacy of contrast-enhanced CISS-3DFT MRI to depict the seventh and eighth cranial nerves affected by vestibular schwannomas. Method All scans were carried out on a 1.5 T MR unit. First, an experimental study was conducted to evaluate the changes in signal intensity of the CISS-3DFT sequence in relation to the concentration of contrast medium. Second, nine consecutive patients with 11 vestibular schwannomas underwent CISS-3DFT imaging before and after contrast agent administration. Signal intensities of the tumors and nerves were measured and compared between the pre- and postcontrast images. Visualization of the facial and cochlear nerves was rated on pre- and postcontrast CISS imaging independently. Results On the phantom study, the CISS-3DFT sequence showed a constant increase in signal intensity as the concentration of Gd-DTPA increased. The contrast between the nerves and tumors significantly increased after contrast agent administration (from 0.1 to 9.0 as mean contrast-to-noise ratio). The ability to depict the nerves was also significantly higher for postcontrast CISS-3DFT imaging than for precontrast. Conclusion Although the CISS-3DFT sequence offers similar contrast as other heavily T2-weighted sequences, the signal intensity of contrast-enhanced tumors increased on CISS-3DFT imaging. Contrast-enhanced CISS imaging was valuable for evaluating the seventh and eighth cranial nerves affected by vestibular schwannomas.

We used constructive interference in steady state (CISS) 3D Fourier transform (3DFT) MRI data sets to obtain three-dimensional (3D) virtual MRI endoscopic views of the intracranial cerebrospinal fluid (CSF) spaces, processing them with a commercially available perspective endoscopic algorithm. We investigated the potential of the intracranial virtual MRI endoscopy applied to visualisation of the pathology in 13 patients with surgically confirmed trigeminal neuralgia (3), hemifacial spasm (3), acoustic neuroma (3), suprasellar germinoma (1), Langerhans cell histiocytosis (1), lateral ventricle nodules (1) and pituitary dwarfism (1). All images were acquired using a 1.5-T imager employing a circular polarised head coil. The CISS-3DFT data sets were transferred to a workstation for processing with the perspective endoscopic algorithm. Postprocessing for virtual MRI endoscopy was possible for all data sets. The lesions in 12 patients, and their complex anatomical relationships with the surrounding structures, were well seen on the 3D images. A small acoustic neuroma in the internal auditory meatus was not seen using virtual endoscopy. Although virtual MRI endoscopy has limitations, it provides 3D images which cannot be acquired using any other procedure.

Recent advances in three-dimensional (3D) data acquisition and postprocessing technologies have been playing a important role in widening the potential applications of 3D display. The authors described new applications of a virtual endoscopic algorithm for 3D display of high resolution MR images: (a) intracranial intravascular virtual MR endoscopy using the 3D fast imaging with steady state precession (FISP) sequence, and (b) virtual MR endoscopy of the cerebrospinal fluid (CSF) spaces using the constructive interference in steady state (CISS) three-dimensional Fourier transform (3DFT) sequence. The virtual endoscopic images were displayed with use of a commercially available perspective volume-rendering algorithm. Our initial experience showed that virtual MR endoscopy can be performed to observe the intracranial arteries and CSF spaces from the viewpoints within themselves. Although the clinical use of the intracranial virtual MR endoscopy has not been established yet, the images obtained are very attractive and further investigations in this field will be expected.

To prospectively compare diffusion-tensor magnetic resonance (MR) imaging anisotropy measurements of white matter (WM) regions in early and late treatment groups of Krabbe disease patients treated with stem cell transplantation.The study was approved by the Institutional Review Board and was compliant with Health Insurance Portability and Accountability Act; informed consent was obtained from the families of all patients. Patients with early-onset Krabbe disease (four girls and three boys) underwent diffusion-tensor MR imaging before and after stem cell transplantation. Fractional anisotropy (FA) values from serial studies were compared in patients who underwent transplantation at less than 1 month (early group, two girls and one boy) and those who underwent transplantation at 5-8 months (late group, two girls and two boys). FA values were measured in the genu and splenium of the corpus callosum, the frontal WM, and the internal capsule; were compared with those of five age-matched children in the comparison group (normal MR images and no proved neurologic disease); and were expressed as a ratio. Images obtained after transplantation were evaluated at approximately 1 (n = 7), 2 (n = 6), 3 (n = 1), and 4 (n = 1) years.Before transplantation, mean FA ratios in the early group for all four WM regions ranged between 97% and 117%. At 1 year, mean FA ratios at all locations were either 92% or 93%. At 2 years after transplantation, mean FA ratios were between 83% and 92%. In one patient imaged at 3 years, the mean FA ratio was 97%; in another patient imaged at 4 years, the mean FA ratio was 77%. Before transplantation, mean FA ratios in the late group ranged between 55% and 74%. Mean FA ratios were between 37% and 50% at 1 year after transplantation and between 36% and 39% at 2 years.All patients had decreases in FA ratios over time. The early group had higher initial FA ratios and lower subsequent decreases, which may indicate amelioration of the dysmyelinating process.

Our aim was to review the MRI appearances of primary intracranial germ-cell tumours (GCT). We reviewed the MRI studies of 32 patients: 19 with germinomas, five with teratomas, one with an embryonal carcinoma, five with mixed and two with malignant nongerminomatous GCT. Eleven were in the pineal region, 12 suprasellar, five in the both sites, two in the basal ganglia and two in the corpus callosum. Contrast-enhanced images were available for 27 patients. The solid parts of GCT were nearly isointense with grey matter on both T1- and T2-weighted images. In seven patients with nongerminomatous GCT high-signal components were found on T1-weighted images, representing haemorrhage, high-protein fluid or fat. Cystic components were detected in 17 of 27 patients; eight germinomas and all nine nongerminomatous GCT had cysts. The solid components of germinomas enhanced homogeneously in eight cases and heterogeneously in 10, while all nongerminomatous GCT showed heterogeneous enhancement. MRI features tumours can facilitate correct diagnosis of GCT, including histological subtypes.

A first-pass, contrast-enhanced three-dimensional (3D) magnetic resonance (MR) angiography with short acquisition time was performed for three consecutive cases with suspected spinal arteriovenous fistula (AVF). This MR technique demonstrated the feeding arteries and draining veins of the spinal dural AVF, and was very useful for the definite diagnosis of the lesions as a disease with arteriovenous shunt. With this MR technique, we could localize the feeding artery and shunt before conventional angiography. J. Magn. Reson. Imaging 2000;12:949–952. © 2000 Wiley-Liss, Inc.

Purpose: To investigate the MR dynamic patterns of neurohypophyseal germ cell tumors (GCTs) for differential diagnosis of infundibular diseases affecting young people. Material and Methods: Eleven patients with neurohypophyseal GCTs underwent dynamic MR studies with T1-weighted spin-echo (SE) or turbo SE techniques. Other infundibular lesions, including adenohypophysitis (n=3), Langerhans' cell histiocytosis (LCH, n=2), and 1 hemangioblastoma from von Hippel-Lindau disease, were also evaluated. Serial images were obtained every 15 s (turbo SE) or 30 s (SE technique) for 240 s after rapid injection of contrast medium. The dynamic patterns were analyzed quantitatively with the contrast medium enhancement ratio. Results: On dynamic MR images, GCTs typically showed a gradual enhancement increase with a peak between 105 s and 180 s, while two showed a relatively rapid increase. LCH and hemangioblastoma showed a dynamic pattern similar to GCTs, while adenohypophysitis demonstrated a sharp rise and a steeper wash-out with an obvious peak before 90 s. Conclusion: Typical dynamic pattern of GCTs was the gradual enhancement increase without wash-out. Dynamic MR imaging can distinguish GCTs from adenohypophysitis, but is not useful for differentiation from LCH.

The degree of tumor malignancy generally correlates to tumor grade, and the direct measurement of tumor vasculature is desired. Dynamic susceptibility contrast magnetic resonance imaging can provide relative cerebral blood volume and, therefore, is one of the most reliable methods to evaluate tumor vasculature in vivo. Tumor vessel size is extremely variable due to complex tumor angiogenesis, and the gradient-echo echo-planar imaging (GE-EPI) technique, which is sensitive to the total vascular bed, is well suited for this purpose. As many studies have shown, dynamic susceptibility contrast magnetic resonance imaging is more useful for grading glioma than conventional magnetic resonance imaging. We found that this technique can also provide supplementary information to differentiate between malignant lymphoma and glioma because the absence of tumor neovascularization of malignant lymphoma leads to low rCBV, which is in contrast to those of malignant gliomas. Indeed, this technique can be used for the differentiation of extra-axial tumors such as between meningioma and neurinoma. Recently, this technique has been focused toward determining the stereotactic biopsy site, monitoring the embolization of effect in meningioma, or evaluation of treatment effects after radiation therapy. However, the value of tumor rCBV is affected by many conditions such as the T1 relaxivity effects of gadolinium in the extravascular space. To establish the usefulness of this technique, further examination will be needed.