Morphological dissociation between visual pathways and cortex: MRI of visually-deprived patients with congenital peripheral blindness.

MRI was used to study possible morphological changes in the visual system in 12 patients suffering from congenital blindness of peripheral (ocular) origin. While their optical pathways showed degeneration, hypoplasia or atrophy in 7 out of 12 cases, the occipital cortex appeared normal in all cases. This dissociation between afferent pathways and the cortex is contrary to the assumption that visually deprived cortex may undergo degeneration. The finding is congruent with evidence that the occipital cortex is used for other, nonvisual functions.

MRI in a case of Sandhoff's disease.

An 18-month-old girl was examined by MRI for progressive psychomotor retardation. T2-weighted images demonstrated abnormal high signal in the putamina and low signal in the thalamus (due probably to calcification). Although the cerebral cortex was markedly atrophic, there were signs of brain enlargement because of swelling of the extensively diseased white matter. The diagnosis of Sandhoff's disease was established by low serum levels of hexosaminidase A and B.

Infratentorial brain maturation: a comparison of MRI at 0.5 and 1.5T.

Our purpose was to establish parameters for normal infratentorial brain maturation at 0.5 and 1.5 T and to evaluate the field strength criteria for the assessment of infratentorial brain maturation with MRI. We examined 27 children with normal psychomotor development (3 days to 24 months) with a 1.5 T system and 22 (4 days to 29 months) with a 0.5 T system; standard T2-weighted spin-echo sequences (TR/TE 2500/90 ms at 1.5 T and TR/TE 2200/90 ms at 0.5 T) were obtained. The signal intensity of infratentorial anatomical structures compared to their surroundings was classified as high, isointense or low by three neuroradiologists. For anatomical structures with age-related contrast changes, the time of these changes was determined statistically for the 0.5 T and 1.5 T system independently. The delineation of the structures without age-related contrast changes at the two field strengths was compared using a chi 2 test. Age-related contrast changed were found in the same anatomical structures ("marker sites") at 0.5 and 1.5 T. Generally, these changes were apparent in larger structures (pons, middle cerebellar peduncles, medulla, cerebellar folia, red nuclei, cerebral peduncles), with only slight field-strength-dependent differences in the time of the contrast changes. Contrast changes from high to isointense signal were observed slightly earlier at 0.5 T and changes from isointense to low signal slightly later at 0.5 T. The delineation of the smaller anatomical structures was significantly better at 1.5 T but these structures did not show age-related contrast changes. The differences in the assessment of infratentorial brain maturation between 0.5 and 1.5 T can be attributed to a lower signal-to-noise ratio at lower magnetic field strengths. These differences do not complicate temporal classification of the stage of infratentorial brain maturation using the same "marker sites" and the same temporal criteria at 0.5 or 1.5 T. However, higher field strengths are preferable for the assessment of smaller structures with physiological signal differences; this may imply better detection of small lesions at higher field strengths.

MRI in patients with general paresis.

Few cases of MRI in neurosyphilis have been reported. We examined the value of MRI in patients with general paresis; MRI was performed on four HIV-negative patients with parenchymatous neurosyphilis. It demonstrated frontal and temporal atrophy, subcortical gliosis and, in one patient, increased ferritin in the basal ganglia. The progression of the lesions on MRI correlated well with the neuropsychiatric disturbances. The MRI findings correlated with the well-known neuropathological findings. This combination of pathological findings in neurosyphilis has not been described before and we suggest that MRI is of prognostic value in patients with general paresis.

Identification of "premyelination" by diffusion-weighted MRI.

OBJECTIVE: The purpose of this study was to compare white matter maturation as demonstrated with diffusion-weighted MRI and with myelin-sensitive histological staining. MATERIALS AND METHODS: The diffusion-, T1-, and T2-weighted SE MRI at 4.7 T was performed weekly in a total of 16 rat pups, aged from 5 days to 8 weeks, 2 animals evaluated per week. Heavily diffusion-weighted sequences were obtained with the diffusion-sensitizing gradient switched alternately in two orthogonal directions. To enhance signal intensity of anisotropic structures, a synthesized image (referred to as the "anisotropy index map") was constructed from the ratio of pairs of images acquired with diffusion sensitization of identical magnitude but orthogonal direction sensitivity. The anisotropy index maps were used for comparison with T1-weighted and heavily T2-weighted SE sequences and histological sections, respectively. RESULTS: The first evidence of diffusion anisotropy on anisotropy index maps preceded initial myelin as well as neurofibril staining by 5-12 days and T2 shortening by 2 weeks. The T1-weighted sequences did not yield visible changes and were not helpful for the assessment of ongoing white matter maturation in this model. CONCLUSION: Magnetic resonance imaging signal intensity changes based on anisotropic water diffusion were demonstrated in regions of unmyelinated cerebral white matter tracts of albino rat pups before the onset of histologically detectable myelin. The ability of in vivo mapping of premyelinating white matter maturation indicates a new diagnostic use of MRI in evaluating cerebral white matter maturation.

Early infantile form of Krabbe disease with optic hypertrophy: serial MR examinations and autopsy correlation.

The development of white matter lesions in a case of autopsy-proved early infantile form of Krabbe disease was monitored by serial MR examinations. Hypertrophy of the optic nerves was present late in the course of the patient's disease and is a remarkable feature in this case.

[Nuclear magnetic resonance tomography findings in obsessive-compulsive disorder]. / Kernspintomographische Befunde bei der Zwangserkrankung.

Eighteen patients with a DSM-III-R diagnosis of obsessive-compulsive disorder (OCD) were imaged by MR and compared to a control group of 18 patients with clinically diagnosed unspecific headaches. Weighted spin-echo sequences were carried out with a 1.5T unit in both axial and coronal planes T1 (TR 700/TE 15 ms) and T2 (TR 2500/TE 15.70). The ferritin distributions in the basal ganglia and in the midbrain were evaluated; in addition, the width of the pars compacta in the midbrain on the basis of the criteria of Braffmann et al. 1988, the widths of the inner subarachnoid spaces on the basis of the ventricular index quotient VIQ (TerBrugge, 1986), and the widths of the outer subarachnoid spaces were conducted. The latter was undertaken by three independent investigators whose results were in agreement with one another. In 12 of the OCD patients (n = 18) there was a total of 25 pathological MRI findings; in the control group there were 6 pathological MRI findings in only 6 of the patients (n = 18). In conclusion pathological changes were found at different locations, but a connection between a specific neuroanatomic system and obsessive-compulsive disorder could not be demonstrated.

Jarisch-Herxheimer reaction in a patient with neurosyphilis.

A 40 year old man presented with progressive personality changes in the previous six months. Specific serological tests for syphilis in blood and CSF were highly positive and CSF sedimentation showed signs of an inflammatory process. Ten hours after the start of penicillin treatment a severe symptomatic Jarisch-Herxheimer reaction with alteration of level of consciousness, pupillary changes, and focal neurological signs developed. Jarisch-Herxheimer reaction may occur in various settings, particularly in the treatment of syphilis. Investigation of CSF before the treatment may predict a potential risk. Corticosteroid treatment has been suggested for prevention.

MR assessment of brain maturation: comparison of sequences.

PURPOSE: To evaluate the role of short-inversion-time inversion-recovery (STIR) sequences in assessment of brain maturation. METHODS: Twenty-seven infants and young children with normal neurologic development were examined by 1.5-T MR using a circularly polarized head coil. Axial T1-weighted and T2-weighted and spin-echo and STIR images were obtained. Signal intensity of different anatomic structures at individual sequences was classified relatively to reference sites and temporal sequence of signal intensity was observed. RESULTS: Signal intensity changes on T1-weighted and T2-weighted spin-echo sequences occurred at ages described in various previous publications. On STIR images intensity changes became apparent at a time between T1-weighted and T2-weighted images. The advantages of the STIR sequence were improved assessment of myelination of subcortical cerebral white matter from 6 to 14 months and good contrast between white matter lesions and cerebrospinal fluid. CONCLUSION: Our results suggest that from 0 to 6 months myelination can be assessed best using a combination of T1-weighted and T2-weighted images; from 6 to 14 months a combination of T2-weighted and STIR images seems to be advantageous; after 14 months the use of only T2-weighted sequences is sufficient. After 14 months STIR images may be useful in detecting small periventricular white matter lesions or in cases with retarded myelination and isointensity between gray matter and white matter.

Posturographic measurement of body sway in survivors of severe closed head injury.

Postural imbalance was measured in 39 survivors of severe closed head injury 7 to 66 months after head injury using a posturographic platform. The results were compared with those derived from age-matched healthy control subjects. Severe postural imbalance, particularly in an anteroposterior direction, was found in 16 patients, whereas 9 patients showed moderate imbalance and 14 patients showed normal results in the posturographic investigation. Low initial Glasgow Coma Scale scores and deep parenchymal brain lesions demonstrated by magnetic resonance imaging were shown to be significant indicators of subsequent severe postural imbalance. The duration of posttraumatic amnesia, the localization and size of cortical contusions and subcortical white matter lesions, on the contrary, were not associated with postural imbalance in the long-term outcome.

Cranial MR imaging and cerebral 99mTc HM-PAO-SPECT in patients with subacute or chronic severe closed head injury and normal CT examinations.

Eighteen patients in the subacute or chronic state following severe closed head injury with normal cranial CT scans were examined by MR and 99mTc HM-PAO SPECT. Correlations were sought between these 2 imaging modalities and the clinical outcome, as defined by the Glasgow Outcome Scale (GOS) score. Both MR and SPECT revealed cerebral damage in all patients examined but structural and functional alterations did not coincide topographically in 64.9% of lesions. Nevertheless, complementary injury patterns suggesting poor recovery were found; cortical contusions and diffuse axonal injury (MR) in conjunction with cortical and thalamic hypoperfusion (SPECT) were noticed in 8 out of 12 patients with unfavorable outcome (GOS = III and IV). The synthesis of MR and SPECT information clearly enhanced the ability both to accurately assess posttraumatic brain damage and to improve patients' outcome prediction.

Superparamagnetic particles as oral contrast medium in magnetic resonance imaging of patients with treated ovarian cancer--comparison with plain MRI.

In 23 patients with treated ovarian cancer, 24 magnetic resonance (MR) examinations of the abdomen and pelvis were performed before and after administration of an oral superparamagnetic contrast medium. Depiction of bowel loops was judged sufficient in 47% with plain scans and in 85% with enhanced scans. Minor artefacts attributed to the agent were noted in 32% of examinations and were classified as disturbing in 8%. The diagnostic information obtained after contrast enhancement was estimated to be superior to that from plain MRI in 20% of patients. The use of oral contrast medium did not alter the MR diagnosis of "tumour recurrence" or "disease-free" in any patient. Our results suggest that superparamagnetic iron oxide is an effective and reliable approach to negative bowel contrast enhancement, increasing the confidence level when distinguishing intestines from solid structures.

[The importance of magnetic field strength in the MR diagnosis of multiple sclerosis: a comparison of 0.5 and 1.5 T]. / Bedeutung der Magnetfeldstärke in der MR-Diagnostik der multiplen Sklerose: Ein Vergleich von 0.5 und 1.5T.

The value of magnetic resonance (MR) to establish the diagnosis of multiple sclerosis (MS) is well known. This study was undertaken to compare MR imaging of the brain of MS patients at high (1.5T) and mid (0.5T) field strength. 25 patients with MS underwent two consecutive MR studies within one hour, each consisting of axial proton density and T2-weighted spin-echo images. Lesions in the supratentorial white matter and corpus callosum and those in the brain stem and cerebellum were separately counted. At 1.5T significantly more lesions were seen than at 0.5T (p < 0.05). Although T2-weighted images at 1.5T added significant information compared to images obtained at 0.5T, in none of our 25 patients the diagnosis was missed at 0.5T. However, at 1.5T dissemination in space was better demonstrated, suggesting MR scanning with high field-units to be favourable in patients with clinically suspected MS.

[Stenosis of the extracranial carotid artery]. / Stenose der extrakraniellen Arteria carotis.

Magnetic resonance angiography (MRA) as well as intraarterial digital subtraction angiography (DSA) were performed in 45 patients suffering from cerebrovascular disease, both procedures within one week of each other. MRA und DSA were evaluated separately for every patient retrospectively by two experienced radiologists on consensus basis. The results were then compared using catheter angiography as gold standard. Evaluation was confined to the common and internal carotid arteries (CCA, ICA) in the neck subdivided into 5 grades of stenosis. A comparative assessment was impossible in 9% cases due to motion artifacts and patient malposition. Out of 18 verified CCA stenoses 13 were demonstrated by MRA and 39 out of 44 ICA stenoses were assessed by MRA. There was a highly significant correlation between degree of stenosis detected by the two methods. Spearman Rank correlation coefficients of 0.824 and 0.913 were found for CCA and ICA, respectively.

Haemorrhage in intracerebral arteriovenous malformations: detection with MRI and comparison with clinical history.

Fifty-one patients with 59 angiographically proven cerebral arteriovenous malformations (AVMs) were examined by high-field MRI to detect blood breakdown products. Results were correlated with the history of intracranial bleeding. Evidence of previous episodes of haemorrhage was seen in 10 of 12 patients (83.3%) with verified bleeding, in 4 of 9 patients (44.4%) with symptoms which could suggest bleeding and in 6 of 30 patients (20%) with negative histories. Because of the known rebleeding rate and the increased risk of associated complications, identification of the subgroup who had had haemorrhage and should therefore be considered for surgery may be beneficial. MRI can make a contribution to management by demonstrating prior haemorrhage in patients with an inadequate clinical history.

MRI of spondylitis.

MRI of proven spondylitis was performed in 39 patients. Acute spondylitis appeared hypointense on T1-weighted and hyperintense on T2-weighted images. Following intravenous administration of Gd-DTPA, enhancement of the marrow and disc was seen. With progressive healing an increasing signal was seen on T1-weighted images. This was caused by the presence of focal fat marrow representing the first sign of therapy response. As healing progressed, the T1-signal increased due to fatty marrow, while the T2-signal decreased as well as the enhancement following Gd-DTPA administration. Therefore, MR imaging can be recommended as the method of choice for early diagnosis of spondylitis and assessment of therapy response.

Septo-optic dysplasia and growth hormone deficiency: accelerated pubertal maturation during GH therapy.

We report four patients (three male, one female) with septo-optic dysplasia and growth hormone deficiency. All had GH therapy for a period of four to eight years until reaching final height. In all four cases bone maturation during puberty was accelerated (1.4 to 1.9 "years"/year), resulting in a final height which was clearly below the predicted height. The progress of pubertal stages was very short in all patients. In three patients TSH and prolactin release after TRH stimulation were increased. These data support a hypothalamic original of the endocrine disorder. Insufficient GH release, even after repeated GHRH stimulation, is in contrast to this assumption. In one case there was a late manifestation of neurohormonal diabetes insipidus, which indicates the possibility of later disease progression. MR imaging of the brain demonstrated variable malformation of the septum pellucidum, chiasma and nervus opticus or the pituitary gland, respectively.

Case report: lipoma of the liver--ultrasound, CT and MR imaging.

A case of lipoma of the liver is presented; ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) findings are reviewed and compared with previous reports. The ultrasound pattern and appearance of the tumour in CT as well as MRI are discussed.

High-resolution real-time sonography and MR imaging in assessment of osteocartilaginous exostoses.

High-resolution real-time ultrasonography (US) and MR imaging, using both spin-echo (SE) and gradient-echo (GE) sequences, were performed prospectively in 14 patients with solitary osteocartilaginous exostoses to assess cartilage cap thickness and bursa formation. Results were compared to surgical and histopathologic findings in all cases. Both US and MR imaging were useful in evaluating exostotic cartilage cap thickness, which is supposed to be the most reliable sign of malignant transformation. Hyaline cartilage matrix had distinctive features in US and MR imaging caused by its specific histologic composition. The formation of bursae over the protruding exostoses, which results in pain and clinically could raise the suspicion of growth and malignant transformation, was demonstrated best using GE sequences. MR imaging was thus superior to US in the detection of bursa formation.