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Background and Purpose: Leukoencephalopathies of unknown origin constitute a considerable problem in child neurology. The purpose of our ongoing study of the subject was to define new disease entities among them by using primarily MR imaging pattern recognition., Methods: We identified seven unrelated patients with a distinct MR imaging pattern consisting of hypomyelination and atrophy of the basal ganglia (neostriatum) and cerebellum (H-ABC). We reviewed the clinical, MR imaging, MR spectroscopic, and laboratory data., Results: Clinically, the patients' diseases were characterized by variably disturbed early development followed by increasing extrapyramidal movement abnormalities, ataxia, and spasticity. Mental capacity was variably affected, but it appeared to be relatively preserved. Parents were not related, and none of their siblings were affected. No metabolic defect was found. Follow-up MR imaging demonstrated atrophy of the cerebral white matter, neostriatum, and cerebellum, which was most pronounced in the most clinically severe cases. Single-voxel proton MR spectroscopic results were normal in the parietal cortex. In the cerebral white matter, myo-inositol and creatine levels were elevated; this finding was compatible with gliosis. N-acetylaspartate and choline levels were normal, suggesting that neither axonal loss nor active demyelination occurred. Proton MR spectroscopic imaging revealed relatively decreased N-acetylaspartate levels in the frontal region., Conclusion: The uniform and highly characteristic MR imaging findings, in combination with the similarities in the clinical findings, provide evidence of a distinct nosologic entity. The acronym H-ABC is offered to indicate patients sharing these clinical and MR imaging features.

We present a patient with posttraumatic tremor who did not show any [(123)I]FP-CIT uptake in the contralateral putamen and caudate. The absence of hypokinesia and rigidity is surprising in the presence of a striatal dopaminergic denervation that is even more severe than in Parkinson's disease. An explanation, therefore, could be that the lesion in the subthalamic nucleus in our patient prevented the onset of a Parkinson syndrome., (Copyright 2002 Movement Disorder Society)

Purpose: The aim of this study was to evaluate the spectrum of developmental anomalies in the caudal region of patients with anorectal malformations (ARM) and relate them to the new insights in the embryogenesis of this region., Methods: Forty-nine patients with ARM were investigated with magnetic resonance imaging (MRI); 24 preoperatively (preop) and 25 postoperatively (postop). Of this group, 17 patients had a high (or intermediate) ARM, 28 a low ARM, and 4 a cloacal malformation (CM). The evaluation of the imaging studies included the level and type of ARM (preop); the developmental state of the sphincter muscle complex (SMC); and the associated anomalies of spinal cord, spine, and urogenital system. The anomalies detected were ordered and related to recent embryologic observations in the caudal region., Results: With MRI, the level of ARM was depicted effectively in 23 of 24 patients (96%) investigated preop, including 5 of 9 clinically proven fistulae in those with high ARM and CM (56%). Maldevelopment of the SMC was observed in 14 of 49 patients (29%). Associated anomalies of spinal cord and spine were found in 51% of patients, more frequently in those with high ARM, low ARM with fistulae, and cloacal malformations. Associated anomalies of the urogenital system were found in 37% of patients., Conclusions: As illustrated by the current study, MRI has become indispensable for the visualization of the nature of congenital ARM and associated anomalies. Moreover, MRI aids in understanding the morphology and pathogenesis of these complex congenital malformations. Based on the MRI and recent embryologic observations, a new and simplified classification of ARM is introduced, including a more appropriate nomenclature., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

Aim: To study the influence of dietary-supplied long-chain polyunsaturated fatty acids on structural brain maturation in preterm infants and to investigate parameters of functional brain development, relating them to structural maturation. Other studies have suggested that dietary supplementation of long-chain polyunsaturated fatty acids in preterm infants may enhance their visual development. The influence on structural brain development has never been evaluated., Methods: In a prospective, double-blind study, 42 formula-fed premature infants were randomized to be fed either a standard preterm formula without long-chain polyunsaturated fatty acids or an identical formula supplemented with docosahexaenoic acid (0.015 g/100 ml) and arachidonic acid (0.031 g/100 ml). Infants with significant cerebral damage, retinopathy, chronic disease or feeding problems were excluded. Follow-up was focused on assessment of cerebral myelination by MRI. Psychomotor, mental and visual development was analysed and flash-visual evoked potentials were recorded., Results: It was found that progress of myelination, mental and motor development and latencies of visual evoked potentials were not positively influenced by supplementation of long-chain polyunsaturated fatty acids. At each test age, visual acuity was slightly better in the supplemented infants than in the non-supplemented infants, but the difference never reached significance level, Conclusion: Supplementation of long-chain polyunsaturated fatty acids did not have a demonstrable positive influence on structural brain maturation. Related to this finding, in this small cohort of preterm infants without significant neurological damage, sample size being restricted by strict inclusion criteria and MRI procedures, no significant positive effects were found on psychomotor, mental and visual development.

Background and Purpose: To date, the demonstration of Rosenthal fibers on brain biopsy or autopsy specimens is considered a prerequisite for a definitive diagnosis of Alexander disease. We initiated a multiinstitutional survey of MR abnormalities in both presumed and confirmed cases of Alexander disease to assess the possibility of an MR-based diagnosis., Methods: MR imaging studies in three patients with an autopsy-based diagnosis of Alexander disease were analyzed to define MR criteria for the diagnosis. These criteria were then applied to 217 children with leukoencephalopathy of unknown origin., Results: Five MR imaging criteria were defined: extensive cerebral white matter changes with frontal predominance, a periventricular rim with high signal on T1-weighted images and low signal on T2-weighted images, abnormalities of basal ganglia and thalami, brain stem abnormalities, and contrast enhancement of particular gray and white matter structures. Four of the five criteria had to be met for an MR imaging-based diagnosis. In a retrospective analysis of the MR studies of the 217 patients, 19 were found who fulfilled these criteria. No other essentially new MR abnormalities were found in these patients. In four of the 19 patients, subsequent histologic confirmation was obtained. The clinical symptomatology was the same in the patients with and without histologic confirmation and correlated well with the MR abnormalities. MR abnormalities were in close agreement with the known histopathologic findings of Alexander disease., Conclusion: The defined criteria are sufficient for an in vivo MR imaging diagnosis of Alexander disease; only in atypical cases is a brain biopsy still necessary for a definitive diagnosis.

Background and Purpose: We applied functional MR imaging with a learning task in healthy elderly volunteers and in patients with Alzheimer's disease to study brain activation during memory performance. The purpose was to determine the feasibility of functional MR imaging during a learning task in healthy elderly volunteers and in patients with Alzheimer's disease and to test our hypothesis that brain activation is decreased in the medial temporal lobe (MTL) memory system in patients with Alzheimer's disease compared with control volunteers., Methods: In 12 patients with mild to moderate forms of Alzheimer's disease and 10 elderly control volunteers, activation of the MTL memory system was studied. We used two learning tasks that required the encoding of new information into memory. After the functional MR imaging experiment, participants were tested for recognition of the encoded objects., Results: In the elderly control volunteers, activation during memory encoding was observed in medial and lateral temporal lobe structures (fusiform, parietal and occipital parts, and hippocampal formation) and in the frontal cortex, as reported previously in studies of young control volunteers. Focusing on the MTL, we observed that activation was significantly decreased in patients with Alzheimer's disease compared with control volunteers in the left hippocampus and parahippocampal gyrus bilaterally during the first encoding task but not during the second (P < .05, uncorrected)., Conclusion: Functional MR imaging with a learning task seems feasible in elderly volunteers and in patients with Alzheimer's disease. The measured functional signal decrease in MTL areas warrants further exploration of the (early) diagnostic usefulness of functional MR imaging in cases of Alzheimer's disease and other dementias.

Background and Purpose: In the early 1980s, diagnosing periventricular leukomalacia (PVL) in neonates by using cranial sonography was possible for the first time. Our purpose was to investigate the possibility of diagnosing PVL in the acute stage by using MR imaging. We evaluated early MR features of hypoxic-ischemic brain injury in neonates with periventricular densities (flares) on cranial sonograms to determine the added value of MR imaging over sonography alone for early diagnosis of brain damage., Methods: In a prospective study, infants who showed flares and/or cysts on sonograms underwent MR imaging during the (sub)acute stage., Results: Fifty infants were classified according to the highest sonographic grade up to the day of MR imaging: 23 infants had sonographic grade 1 (flares < 1 week), 15 had sonographic grade 2 (flares > or = 1 week), four had sonographic grade 3 (small localized cysts), and eight had sonographic grade 4 (extensive periventricular cysts); none had sonographic grade 5 (multicystic leukomalacia) on the day of MR imaging. Overall, the additional information provided by MR imaging (over sonography alone) consisted of the depiction of hemorrhagic lesions in 64% of the infants. Extent and severity of the hemorrhages varied from isolated punctate lesions to extensive hemorrhages throughout the white matter; the latter were followed by cystic degeneration at autopsy in two infants. In nine of the 12 infants with cystic PVL, MR images showed more numerous or more extensive cysts. In addition, in two infants, MR images showed cysts not present on sonograms. In 32% of the infants, MR imaging provided no additional information; in these children, all but one had flares on sonograms whereas MR images showed no abnormalities or a zone of mild periventricular signal change., Conclusion: MR imaging can depict the precise site and extent of hypoxic-ischemic brain injury at an earlier stage and allows a wider differentiation of lesions as compared with sonography alone. Hemorrhagic PVL is considered to be rare, but was present in 64% of our study population.

Purpose: To categorize leukoencephalopathies of unknown origin into a few major groups by using magnetic resonance (MR) imaging criteria to facilitate further studies, and to assess the possibility of defining "new" (i.e., until now unknown) disease entities within these major groups., Materials and Methods: MR images of 92 patients (55 male, 37 female; mean age, 9.3 years) with a leukoencephalopathy were examined by using a scoring list of 68 items. Seven major categories were defined according to the predominant location of the white matter abnormalities. Statistical analysis was used to assess the validity of these seven categories., Results: Statistical analysis results showed that the seven categories could be well distinguished by either using the defining variables initially accepted as inclusion criteria or selecting a few other variables found to have discriminating value. The additional variables confirmed that the categories are essentially distinct and vary systematically with regard to items other than the inclusion criteria. The existence of two recently defined leukoencephalopathies was confirmed, but no consistent evidence of other new disease entities could be provided., Conclusion: Establishing these seven categories helps in the interpretation of individual studies by demonstrating features that the patient has in common with other patients, and it may facilitate further research on homogeneous subgroups of patients and allow pooling of data across multiple centers.

A number of functional brain imaging studies indicate that the medial temporal lobe system is crucially involved in encoding new information into memory. However, most studies were based on differences in brain activity between encoding of familiar vs. novel stimuli. To further study the underlying cognitive processes, we applied a parametric design of encoding. Seven healthy subjects were instructed to encode complex color pictures into memory. Stimuli were presented in a parametric fashion at different rates, thus representing different loads of encoding. Functional magnetic resonance imaging (fMRI) was used to assess changes in brain activation. To determine the number of pictures successfully stored into memory, recognition scores were determined afterwards. During encoding, brain activation occurred in the medial temporal lobe, comparable to the results obtained by others. Increasing the encoding load resulted in an increase in the number of successfully stored items. This was reflected in a significant increase in brain activation in the left lingual gyrus, in the left and right parahippocampal gyrus, and in the right inferior frontal gyrus. This study shows that fMRI can detect changes in brain activation during variation of one aspect of higher cognitive tasks. Further, it strongly supports the notion that the human medial temporal lobe is involved in encoding novel visual information into memory.

Three patients with 3-hydroxy-3-methylglutaryl coenzyme A lyase deficiency were examined with MR imaging and proton MR spectroscopy. In two patients, both clinically normal, MR images showed a diffuse mild abnormality in signal intensity of the cerebral white matter, with multiple foci of more pronounced signal abnormality superimposed. In the third patient, who was clinically retarded and had a cerebral visual impairment, MR imaging showed, in addition to a diffuse signal abnormality of the cerebral white matter, atrophic scarring of the occipital lobes and abnormal signal intensity of the thalami and basal ganglia. It is highly probable that the additional lesions in the occipital lobes and basal nuclei were related to the episode of severe neonatal hypoglycemia the patient experienced. The MR spectroscopic abnormalities correlated with the degree of disease as evidenced by MR imaging.

In the literature, some controversy still exists about the normal and abnormal development of the human anorectum. Therefore, a three-dimensional and histological study was performed on human embryos. In early anorectal development (< or = 49 days postfertilization), the cloaca plays a crucial role, separated from the amniotic cavity by its cloacal membrane. In the cloaca, the yolk sac/primitive hindgut and allantois/primitive urogenital sinus enter. During the embryonic caudal folding process, incorporation of these structures occurs, including their surrounding extraembryonic mesoderm, which fuses to form the urorectal septum. Consequently, this septum does not grow in the direction of the cloacal membrane, and fusion of these structures is likewise never observed. The cloaca remains as such until the cloacal membrane ruptures by apoptotic cell death. The dorsal part of the cloaca then becomes part of the amniotic cavity, and is by no means involved in the development of the anorectum. The tip of the urorectal septum will become the perineal area. Soon after rupture of the cloacal membrane, during late anorectal development (> or = 49 days postfertilization), a secondary occlusion of the anorectal canal occurs, first due to adhesion, followed by formation of an epithelial "plug" at the level of the anal orifice. Recanalization, by apoptotic cell death, of this secondary occluded anal orifice occurs later during development. Based on these embryological observations, congenital anorectal malformations with an abnormal communication to the exterior are best explained as early embryonic defects. The abnormal communications, usually called fistulae, should be regarded as ectopic anal orifices. Anorectal malformations with the anus in normal position are best explained as late embryonic defects.

Congenital anorectal malformations are found in many forms, and are frequently associated with other anomalies, especially of the spinal cord, spine, and urogenital system. Decisions concerning initial management of children with anorectal malformations can be made only after accurate determination of (a) the level and type of malformation, (b) the type of fistula, (c) the developmental state of the sphincter muscle complex, and (d) the presence of associated anomalies. Magnetic resonance imaging has proven to be the only modality to answer all these crucial questions, and has contributed to a better insight in the morphology and pathogenesis of such complex congenital malformations.

Phase-contrast cine MR flow imaging through the aqueduct was used to establish the diagnosis of normal pressure hydrocephalus (NPH), and to predict outcome after shunting. From 1990-1994 16 patients, who were participants in the Dutch Normal Pressure Hydrocephalus Study [3], were studied. The patients included in this study met clinical and CT-scan criteria as described in this study, underwent cine phase-contrast MR imaging prior to placement of a CSF shunt, and had a follow-up 12 months after the operation. Claustrophobic patients, patients with a pacemaker or extremely agitated patients were excluded. Normal Flux was calculated in each patients, as the average difference in caudal and rostral flux (Fdiff) +2 times standard deviation (0.97 cc/sec) [2]. The clinical outcome was measured with a modified scale of activities of daily living (ADL) as described by Rankin. Of the 16 patients, 8 could not be evaluated due to restlessness during MR measurements, disabling cerebral vascular accidents or death before the end of the follow-up period. Of the remaining 8 patients, 5 had a normal flux, of which only one improved. Two patients had a Fdiff twice the normal range, which improved in both patients. One patient had no measurable flux, consistent with an aqueduct stenosis; he too improved. Overall, there was a concordance of MR findings with final outcome after shunting in 7 out of 8 patients. This pilot study, therefore, support the need to further evaluate flow with MR imaging techniques to select patients with shunt responsive NPH.

We compared MRI criteria used to predict conversion of suspected multiple sclerosis to clinically definite multiple sclerosis. Seventy-four patients with clinically isolated neurological symptoms suggestive of multiple sclerosis were studied with MRI. Logistic regression analysis was used to remove redundant information, and a diagnostic model was built after each MRI parameter was dichotomized according to maximum accuracy using receiver operating characteristic analysis. Clinically definite multiple sclerosis developed in 33 patients (prevalence 45%). The optimum cut-off point (number of lesions) was one for most MRI criteria (including gadolinium-enhancement and juxta-cortical lesions), but three for periventricular lesions, and nine for the total number of T2-lesions. Only gadolinium-enhancement and juxta-cortical lesions provided independent information. A final model which, in addition, included infratentorial and periventricular lesions, had an accuracy of 80%, and having more abnormal criteria, predicted conversion to clinically definite multiple sclerosis strongly. The model performed better than the criteria of Paty et al. (Neurology 1988; 38: 180-5) and of Fazekas et al. (Neurology 1988; 38: 1822-5). We concluded that a four-parameter dichotomized MRI model including gadolinium-enhancement, juxtacortical, infratentorial and periventricular lesions best predicts conversion to clinically definite multiple sclerosis.

Purpose: To compare two magnetic resonance (MR) imaging techniques for demonstration of vascular contact with the trigeminal nerve., Materials and Methods: Thirteen patients with unilateral trigeminal neuralgia and 50 control subjects underwent three-dimensional fast inflow with steady-state precession (FISP) and contrast material-enhanced magnetization-prepared rapid acquisition gradient-echo (MP-RAGE) MR imaging. The images were independently reviewed by two neuroradiologists, who were blinded to the clinical details. Six of the 13 patients underwent surgery., Results: Vascular contact with the trigeminal nerve at the root entry zone was seen on FISP images in 10 of 13 (77%) symptomatic nerves and in eight of 113 (7%) asymptomatic nerves (P < .001). MP-RAGE and FISP images demonstrated arterial contacts equally well. MP-RAGE images demonstrated one additional venous contact at the root entry zone in a patient with ipsilateral trigeminal neuralgia. Interobserver agreement was good for both FISP (kappa = 0.69) and MP-RAGE (kappa = 0.78) images. The presence of vascular contact at the root entry zone, seen on preoperative MR images, was confirmed in all six patients who underwent surgery., Conclusion: Both FISP and MP-RAGE MR imaging are useful in demonstrating vascular contact with the trigeminal nerve at the root entry zone in patients with trigeminal neuralgia.

Purpose: To investigate the intersubject and intrasubject variability of the activated area in the visual cortex with functional MR imaging., Methods: Double-section gradient-echo MR images were acquired at 1.5 T in 28 healthy volunteers using the fast low-angle shot (FLASH) technique. Visual stimulation was obtained with light-emitting diode (LED) goggles. Eighteen volunteers were studied twice. The size of the activated areas in the visual cortex and the increase in signal were measured. A reproducibility ratio for size (R[size]) and for location (R[overlap]) was calculated on a scale of 0.0 to 1.0., Results: Activation was seen in 89% of the subjects. The size of the activated area was widely variable among subjects: mean, 460 +/- 284 mm2; range, 0 to 1029 mm2 in the first study in all volunteers. Signal increases ranged from 3.2% to 10.9%, with a mean of 6.6 +/- 1.7%. The mean values of intrasubject variability testing were R(size) = 0.83 +/- 0.16 and R(overlap) = 0.31 +/- 0.11., Conclusion: Functional MR imaging with the FLASH technique is useful in identifying certain cortical areas that have quite variable locations among subjects. This study provides reference data for the intrasubject and intersubject variability of the activation pattern of the visual cortex.

A survey was performed of magnetic resonance imaging (MRI) findings in 21 patients with congenital muscular dystrophy (CMD) with cerebral abnormalities to evaluate the contribution of MRI to the classification of CMD patients. In 5 patients with Walker-Warburg syndrome (WWS), MRI showed hydrocephalus due to aqueduct stenosis, generalized cerebral cortical agyric or pachygyric polymicrogyria, diffuse cerebral hemispheric white matter abnormalities, and malformations of posterior fossa structures. In 4 patients with muscle-eye-brain disease, MRI showed cortical dysplasia, but less severe than in WWS. The cerebral white matter either was normal or contained multiple focal abnormalities. Malformations of posterior fossa structures were present. Eight patients, classified as having classic merosin-deficient CMD (MD-CMD), had diffuse cerebral hemispheric white matter abnormalities, no other abnormalities. One patient with MD-CMD had only a few, focal white matter abnormalities. Three CMD patients had occipital agyria, otherwise normal gyration, multifocal or more diffuse cerebral white matter changes, and variable hypoplasia of pons and vermis. Two of the 3 patients had negative muscle merosin staining. The conclusion of the study is that MRI is an important adjunct in the classification of CMD patients. CMD with occipital agyria can be regarded as a newly recognized, separate CMD subtype.

Purpose: To determine whether the MR appearance of the spinal cord in patients with multiple sclerosis (MS) differs according to clinical subtype., Methods: The spinal cords of 20 healthy control subjects and 60 patients with MS (22 with relapsing-remitting disease, 22 with secondary-progressive disease, and 16 with primary-progressive disease) were examined with sagittal dual-echo spin-echo MR imaging and with axial T2*-weighted gradient-echo MR imaging. Two interpreters scored the images for focal lesions and for diffuse abnormalities. Cross-sectional areas of the cords were measured at the C-2 level., Results: No abnormalities were found in any of the control subjects nor in two of the patients. Fifty (83%) of 60 patients had focal lesions. Diffuse abnormality and focal lesions were found in 50% of patients with secondary-progressive MS, in 25% of patients with primary-progressive disease, and in 18% of patients with relapsing-remitting disease. Diffuse abnormality without focal lesions was found in seven patients with primary-progressive MS and in one patient with secondary-progressive MS. Patients with diffuse abnormalities had a smaller cross-sectional area of the spinal cord and they suffered from more disability than did patients without diffuse abnormalities., Conclusion: The MR appearance of the spinal cord differs among clinical subgroups of MS. Diffuse abnormality of the spinal cord is associated with a progressive clinical course and greater disability.

It has been suggested that subjects with increased vertical craniofacial dimensions have relatively oblique orientated jaw muscles with a reduced possibility to restrain the vertical component of craniofacial growth. To test this hypothesis, relationships were investigated between the spatial orientation of the jaw muscles and the craniofacial morphology. Computer reconstructions of the external shape of the jaw muscles of 30 adult males with a normal skull were made with the use of serial magnetic resonance imaging (MRI) scans. The orientation of the jaw muscles was defined by a regression line through the centroids of the serial cross-sections. Sagittal and frontal projections of the moment arms of the muscles were measured with respect to the centre of the ipsilateral condyle. Craniofacial morphology was analysed three-dimensionally using lateral head films and coronal MRI scans. The cephalometric data were analysed statistically using regression and factor analyses. Six cephalometric factors with Eigen values higher than 1 were correlated with jaw muscle orientation and moment arm data, using a multiple regression analysis. The anterior face height factor was significantly correlated with the orientation of the jaw opening muscles in the sagittal plane but was not significantly correlated with the orientation of the mandibular elevators. The sagittal moment arms of the mandibular elevators showed significant correlations with the factors describing the gonial angle and the posterior face height. It was concluded that the variation of spatial orientation of the human jaw closing muscles is predominantly associated with the variation of mandibular morphology (expressed by the gonial angle) and the posterior face height. The orientation of the jaw opening muscles shows significant relationships with anterior vertical craniofacial dimensions. The hypothesis that persons with an increased anterior face height have relatively oblique orientated jaw elevators was rejected.

Rationale and Objectives: Definition of optimal magnetic resonance (MR) scanning plane and conventional MR sequence for the detection of mesial temporal sclerosis (MTS)., Methods: Coronal and axial T2-weighted images and axial T2-weighted images parallel to the long axis of the hippocampus (APLAH) and coronal inversion recovery (IR) images were obtained in patients with medically intractable temporal lobe epilepsy in their phase 1 preoperative evaluation. Thirty-three consecutive MR scans were reviewed by a panel of three radiologists. Twenty-three patients had MR abnormalities consistent with MTS, and ten scans were normal. To assess the best single scanning technique, another group of three radiologists, who were masked to all patient data, individually assessed the different planes and sequences of the 33 studies presented separately in a random fashion. For each plane and sequence, the likelihood (L) ratio for the correct diagnosis was determined separately., Results: For all planes considered separately, a likelihood ratio of 4.4 was optimal for the coronal T2-weighted images. The likelihood ratio of APLAH T2 was 2.2; of axial T2, 3.9; of coronal IR, indefinite because of 100% specificity., Conclusions: For the assessment of MTS, coronal T2-weighted images were considered the best single scanning technique.

A study was performed in 48 neurologically normal preterm and term-born infants, with a postconceptional age at MRI varying between 30 2/7 and 46 weeks and a mean age of 34 2/7 weeks. The purpose of the study was to determine the normal progress of myelination on MRI in that age range. T1- and T2-weighted images of the brain were assessed for changes in signal intensity of white matter relative to gray matter. Multiple sites in the brainstem, cerebellum and cerebral hemispheres were assessed separately. The findings were correlated with the ages of the infants. As judged from relative signal intensities, myelin was present at the post-conceptional age of 30-34 weeks in the following structures: tegmentum pontis (in particular medial lemniscus), superior and inferior colliculi, decussation of the superior cerebellar peduncles, crura cerebri, ventrolateral thalamus, lateral globus pallidus, dorsolateral putamen, dentate nucleus, middle and superior cerebellar peduncles, vermis cerebelli, cortex bordering the central sulcus and hippocampus. Little progress in myelination was noticed up to the post-conceptional age of 46 weeks. Between 34 and 46 weeks, myelin appeared in the lateral part of the posterior limb of the internal capsule and in the central part of the corona radiata and became more prominently visible in the cortex bordering the central sulcus.

We identified nine children with a leukoencephalopathy of similar type according to clinical and MRI findings. The patients included three affected sibling pairs. The age range was 3 to 19 years. The onset of the disease was in childhood; the course was both chronic-progressive and episodic. There were episodes of deterioration following infections and minor head traumas, and these could results in unexplained coma. In eight patients with advanced disease, MRI revealed a diffuse cerebral hemispheric leukoencephalopathy, in which increasing areas of the abnormal white matter had a signal intensity close to that of CSF on all pulse sequences. In one patient in the early stages of disease, initial MRI showed diffusely abnormal cerebral white matter, which only reached the signal characteristics of CSF at a later stage. In the patients in whom the disease was advanced, magnetic resonance spectroscopy (MRS) of the white matter showed an almost complete disappearance of all normal signals and the presence of glucose and lactate, compatible with the presence of mainly CSF and little brain tissue. Spectra of the cortex were much better preserved. However, in addition to the normal resonances, there were signals representing lactate and glucose. MRS of the white matter in the patient whose disease was at an early stage was much less abnormal. Autopsy in one patient confirmed the presence of extensive cystic degeneration of the cerebral white matter with reactive change and a preserved cortex. Typical involvement of pontine tegmental white matter was suggested by MRI and confirmed by autopsy. The disease probably has an autosomal recessive mode of inheritance, but the basic metabolic defect is not known.

Aims: The accuracy of magnetic resonance angiography in detecting proximal coronary artery stenoses is unclear. We postulated that fast magnetic resonance angiography is capable of (1) imaging proximal coronary arteries, and (2) detecting stenoses of > or = 50% of their luminal diameter., Methods and Results: Thirty-five patients, referred for analysis of angina pectoris, underwent both conventional angiography and magnetic resonance angiography of coronary arteries. A fast k-space segmented gradient-echo technique was used during breath-holds. Two observers, blinded to the results of conventional angiography, independently analysed the magnetic resonance studies for (1) length of visualized segments, and (2) presence of signal voids indicative of stenoses. From 140 proximal arteries, 15 (11%) were excluded because of incomplete imaging or degraded image quality. Mean length of the visualized segments was 9 +/- 4 mm for the left main, 62 +/- 16 mm for the left anterior descending, 21 +/- 9 mm for the left circumflex and 89 +/- 32 mm for the right coronary artery. Sensitivity for detecting > or = 50% luminal diameter stenoses was 0.00 for the left circumflex, 0.53 for the left anterior descending coronary artery, 0.71 for the RCA and 1.00 for the left main artery. Specificity varied from 0.73 for the left anterior descending coronary artery to 0.96 for the left circumflex. Inter-observer agreement was 0.90., Conclusion: Thus, segmented magnetic resonance angiography is capable of non-invasive imaging of proximal coronary anatomy. Its good accuracy in detecting left main coronary artery disease, intermediate accuracy in detecting right coronary artery and left anterior descending coronary artery stenoses, and low accuracy in detecting left circumflex lesions fit within a range of sensitivities and specificities found by others. Further technical advances are necessary to make the technique clinically robust.

We studied the appearance of retinoblastoma on unenhanced and gadolinium-enhanced images and the accuracy of tumour staging with MR imaging. The MR images were obtained in 18 children with retinoblastoma and compared with histopathological findings after enucleation. The MR imaging included T1-weighted and dual-echo T2-weighted images before, and T1-weighted images after, gadopentetate dimeglumine injection. The contrast between tumour and ipsilateral vitreous strongly increased (57 %) after gadolinium on T1-weighted images (p = 0.004). Tumour was strongly hypointense as compared with ipsilateral vitreous in all patients using heavily T2-weighted (TE = 120 ms) images (p = 0.001). The estimated T2 of tumour (mean 96 + 14 ms) did not correlate with histological grading or degree of calcification. Unenhanced T1-weighted MR images rightfully excluded extrascleral growth in 16 of 16 cases, but its presence was confirmed after enucleation in only one of 2 abnormal MR scans. Invasion of the optic nerve behind the cribriform plate was confirmed in 2 of 3 abnormal gadolinium-enhanced MR scans, but also in 1 of the 15 cases in which MR images were normal. The T2-weighted images were useful in assessing retinal detachment. We conclude that heavily T2-weighted images, unenhanced T1-weighted images and gadolinium-enhanced T1-weighted MR images are complementary in characterizing and staging retinoblastoma.

Using both quantitative computer-assisted analysis and visual estimation the MR imaging response of brain metastases to whole-brain radiotherapy (WBRT) was prospectively studied in 49 patients. Compared to the computer-assisted analysis, the precision of the visual estimation (by two readers in conference) of tumor response was determined. Also the radiological response was related to the clinical response. Six weeks after WBRT follow-up MR was performed in 27 of 49 patients. Of the remaining 22 patients without follow-up MR, 9 had died or deteriorated due to neurologic decline. In four patients (15%) tumor increase was demonstrated by computer-assisted analysis; in the other 23 patients tumor remained stable (15%) or decreased (70%). In 11 of the 27 patients, a second follow-up MR was obtained 26 wk after WBRT demonstrating tumor increase in seven patients (64%). Complete discordance between both assessment methods was noticed in only 4 of 38 MR scans (27 scans 6 wk after WBRT and 11 scans 26 wk after WBRT) with small quantitative changes in tumor volume. In 26 of 38 (68%) observations 6 and 26 wk after WBRT, there was a positive correlation between change in tumor volume and change in the Neurologic Status. Visual estimation analysis seems an appropriate method of routine therapy monitoring in individual patients with brain metastases. The computer-assisted analysis should be considered if precise response monitoring becomes critical.

The purpose of this study was, first, to evaluate correlations between four potential magnetic resonance (MR) parameters for severe tissue destruction in multiple sclerosis (MS) lesions. Second, to evaluate the effect of incidental magnetization transfer (MT) effect on hypointense lesions in multislice T1 spin echo (SE) imaging. In 49 lesions, from 10 MS patients, MT ratio (MTR), T1 relaxation time, signal intensity (SI) on T1-weighted SE images normalized to normal-appearing white matter (NAWM), and SI normalized to cerebrospinal fluid (CSF) were measured. Differences in contrast of hypointense lesions were measured between single slice and multislice imaging. MTR correlated significantly (p < .001) with longitudinal relaxation rates (1/T1) (r = 0.84), SI normalized to NAWM (r = 0.78), and SI normalized to CSF (r = 0.75). The degree of reduction in contrast, caused by multislice imaging, correlated significantly with MTR of lesions (r = 0.60, p < .001), leading to reduction of hypointense lesion load (p < .01). We conclude that all four MR markers for severe tissue destruction are highly correlated when applied to selected hypointense lesions on T1-weighted SE images. Due to "incidental" off-resonance excitation, contrast and hypointense lesion load will be reduced in multislice T1-weighted SE images.

Occasionally, striking abnormalities are found on MRI in patients with mild neurological disturbances. In most of these cases the diagnosis is not immediately evident and the history does not provide an unequivocal explantation. We present a patient with extensive symmetrical white matter abnormalities in the posterior temporal, temporo-occipital and parietal regions, 24 years after documented severe meningococcal meningoencephalitis. A meningitic vasculitis, affecting the insular branches of the middle cerebral arteries, could have been responsible for these changes.

Inhomogeneous patient samples have been used in previous studies to determine the power of magnetic resonance imaging (MRI) for trial monitoring in multiple sclerosis (MS). These power-calculations might not be applicable to the active relapsing-remitting patient who is preferably included in trials. In order to reevaluate the power-calculations for MRI in the monitoring of treatment in strictly relapsing-remitting MS and to compare the power of different trial designs we studied 12 relapsing-remitting MS patients prospectively for a median period of 12 months using monthly clinical assessments and gadolinium-enhanced MRI. A median number of two clinical relapses/patient occurred of which a median of one was treated with steroids. A median of 1.59 new lesions/scan/patient was detected (range 0-8). The total number of new active lesions correlated significantly with study period relapses (SRCC = 0.72, P = 0.023). Computer simulations using the bootstrap technique yielded mostly lower power values for a parallel groups design than in previous studies except for short follow-periods in larger samples. In this-sample the open cross-over design was found to be between 20 and 40% more powerful. Results of power-calculations are clearly sample dependent implying that for treatment trial monitoring using MRI in relapsing-remitting MS conservative sample size estimates are to be used. In an active patient group open cross-over trial designs could be a very powerful alternative to parallel groups design.

Changes in cortical metabolism and cerebral perfusion may be recorded non-invasively with functional magnetic resonance imaging (fMRI). In pilot experiments, using fMRI with photic stimulation, we found differences between activated areas when the left or the right eye was stimulated separately. In this study we investigated whether this could be explained by ocular dominance. We studied 26 healthy volunteers (mean age 23.3 +/- 3.5 years). Ocular dominance was determined by means of the near-far alignment test. fMRI-measurements consisted of a double-slice gradient echo sequence. Slices were acquired placed parallel on either side of the calcarine fissure. Visual stimulation was done with goggles with two LED matrices (red light, 8 Hz); each in front of one eye. In each subject, the left and right eye were stimulated separately and together, in a randomly alternating order. Twenty-two subjects showed activation, of whom eight subjects had a dominant left eye and 14 a dominant right eye. In general the size of the activated area was bigger upon stimulation of the dominant eye. The difference with the area upon stimulation of the non-dominant eye was statistically significant in the right eye dominant group. These results indicate that the dominant eye actually activates a larger area of the primary visual cortex than the non-dominant eye. This provides for the first time a functional basis for the concept of ocular dominance.

Purpose: To compare cardiac-triggered dual-echo spin-echo and magnetization transfer-prepared gradient-echo (MT-GE) MR imaging in the detection of multiple sclerosis (MS) lesions in the spinal cord., Methods: The cervical spinal cord in 20 patients with MS and in nine healthy volunteers was examined with spin-echo and MT-GE MR imaging. Sagittal images were scored for number of lesions, certainty about lesions, image quality, and visual hindrance by artifacts in random order by two radiologists separately and in a blinded manner., Results: In one healthy volunteer, a lesion was seen on images obtained with both images. Lesion/cord contrast-to-noise ratio was equal on both the MT-GE and T2-weighted spin-echo images. MT-GE images showed better image quality and fewer artifacts than the spin-echo images did. The readers found approximately the same number of lesions. However, the number of definite lesions was higher for the spin-echo sequence than for the MT-GE sequence. One reader found 45 definite lesions with spin-echo and 34 definite lesions with MT-GE. For the other reader, these numbers were 37 (spin-echo) and 31 (MT-GE). On the spin-echo images, 90% of the patients were considered to have definite lesions; on the MT-GE images, the readers found definite lesions in 65% (reader 1) and in 70% (reader 2) of the patients., Conclusion: Image quality was better with the MT-GE technique than with the spin-echo technique, and lesion/cord contrast-to-noise ratio on the MT-GE images was equal to that of T2-weighted spin-echo images. However, for detecting spinal cord MS lesions in the sagittal plane, the spin-echo images were preferred to the MT-GE images.

Three patients with propionic acidemia were studied. The first patient was diagnosed at the age of 9 mo, 3 mo after he developed hypotonia and choreoathetoid movements after an upper respiratory tract infection. The second patient was diagnosed at the age of 1.5 mo when she became comatose after nasogastric tube feeding because of failure to thrive. The third patient was diagnosed at the age of 5 d when she presented with feeding difficulties, hypotonia, and respiratory insufficiency. Magnetic resonance imaging (MRI) of the brain in all patients revealed delayed myelination and some cerebral atrophy. In the patient with choreoathetosis, MRI showed bilateral abnormalities in the signal intensity of the putamen and caudate nuclei. MRI of the other two patients showed normal basal ganglia. Proton magnetic resonance spectroscopy (1H MRS) from a voxel located in the basal ganglia revealed a decrease in N-acetylaspartate and myo-inositol peaks and an elevation of glutamine/ glutamate. The presence of spectroscopic abnormalities in a stable metabolic condition, in particular the rise in glutamine/ glutamate, indicates that the metabolic balance on cerebral parenchymal level is less optimal than estimated from biochemical analysis of urine, plasma, or cerebrospinal fluid.

Recently, we described an as yet unidentified white matter disorder in eight patients which probably has an autosomal recessive mode of inheritance. The disease was characterized by megalencephaly and leukoencephalopathy with onset during the 1st year of life and a delayed onset of slowly progressive neurological dysfunction. No basic biochemical defect could be identified. Brain biopsy was performed in one of the patients and the histopathological findings are described in the present report. A spongiform leukoencephalopathy was revealed, without cortical involvement. Most vacuoles were covered by single five-layered membranes, representing single myelin lamellae. Some vacuoles were partially covered by multi-lamellar myelin sheaths or oligodendroglial cell extensions. The vacuoles were never found in the middle or inner parts of myelin sheaths, but involved the outermost lamellae of myelin sheaths only, whereas the remainder of the myelin sheaths remained undisturbed. The histopathological findings place the disease among the vacuolating myelinopathies, although it is distinct from the well-known forms. Possible pathophysiological mechanisms are splitting of the outermost myelin lamellae at the intraperiod line or a disturbance of compaction of the outermost myelin lamellae at the intraperiod line.

Purpose: To provide a practical standard for normal development of gyri and sulci in preterm and term neonates., Materials and Methods: Thirty-nine living preterm infants without substantial neurologic problems underwent magnetic resonance (MR) imaging of the brain. Five infants who were born at term but died of a nonneurologic disorder within 1 week and who underwent autopsy were examined after death with MR imaging. Seven cerebral surface areas were defined, and the development of gyri and sulci in each area was assigned a score between 1 and 5., Results: The postconceptional age (PCA) range of the newborns was 30-42 weeks. When the gyral development scores were assessed as a function of PCA, four transition points could be discerned for the brain as a whole; these transitions occurred at PCAs of 32, 34, 37, and 40 1/2-41 weeks. These four transition points allowed the general gyral development to be divided into five stages. Development of gyri and sulci was most advanced in the area of the central sulcus and the medical occipital area. Development was latest in the frontobasal and frontopolar areas and the anterior part of the temporal lobe., Conclusion: A simple staging system allows easy assessment of the progress of cerebral gyration and sulcation in preterm and term infants.

Objective: MR coronary angiography is most often performed using two-dimensional techniques. Although three-dimensional (3D) acquisitions do have important advantages, they take too long for a single breath-hold and are thus susceptible to respiratory motion artifacts. The purpose of this study was to investigate the accuracy of a unique respiratory-gated 3D MR angiographic technique in identifying the proximal coronary arteries in patients suspected of having coronary artery disease. In addition, we investigated the capability of this technique to detect proximal stenoses., Subjects and Methods: We performed a prospective blinded study in 20 patients who were referred for conventional coronary angiography. A cardiac-gated 3D gradient-echo sequence with fat suppression was used. Retrospective respiratory gating was performed using navigator echoes of the diaphragm position. Using multiplanar reformatting, two independent readers blindly analyzed the data sets for visualization of major coronary arteries, lengths of imaged segments, and detection of significant stenoses (> 50% occlusion of the luminal diameter by conventional angiography)., Results: Seventy-seven of 80 (96%) coronary arteries were positively identified. In one patient, an anomalous coronary anatomy was readily identified and confirmed by conventional angiography. The average lengths of the imaged segments of the right, left main, left anterior descending, and left circumflex coronary arteries were 58 +/- 13 mm, 9 +/- 5 mm, 59 +/- 16 mm, and 24 +/- 10 mm, respectively. Overall sensitivity for the detection of stenoses was low (38%), with a specificity of 95%. Interobserver agreement was 0.92, with a kappa value of 0.65., Conclusion: Respiratory-gated 3D MR angiography allows accurate identification of proximal coronary arteries and may be valuable for 3D imaging of coronary anomalies. Further technical improvements are required to enhance the value of the technique in detecting stenoses.

Objective: To investigate the frequency of lumbosacral anomalies, the association with urogenital abnormalities, and the correlation with defaecation pattern by magnetic resonance imaging (MRI)., Methods: A prospective analysis was performed of routine MRI in patients with anorectal malformations. Between 1990 and 1994, MRI was performed in 43 such patients: 31 boys and 12 girls. Twenty four had a high anorectal malformation, 16 had a low anorectal malformation, and three had Currarino's triad. MRI was performed before reconstruction in 26, and postoperatively in 17. Urogenital anomalies were found in 21., Results: Abnormalities of the spinal cord and spine were found with MRI in 20 patients (46.5%); caudal regression syndrome in 10, tethered cord in two, a combination of both in three, and other spinal anomalies in five. These anomalies were found in 30% of the patients with low anorectal malformations, and in 50% with high anorectal malformations. In patients with urogenital malformations, MRI more often showed spinal anomalies (13/21, 62%) than in patients without (7/22, 32%). In high anorectal malformations, defaecation was more often a problem in patients with spinal anomalies (12/15, 80%) than in patients without (2/8, 25%)., Conclusions: Spinal anomalies in the lumbosacral region were found with MRI in 46.5% of patients with anorectal malformations. Since presence of these anomalies seems to be related to clinical outcome, MRI should be performed routinely in all such patients.

A case-control study of epilepsy in multiple sclerosis (MS) is presented using magnetic resonance (MR) imaging to semiquantitatively assess cortical-subcortical lesion load. In this sample of 13 pairs of cases with MS and epilepsy and controls with MS without epilepsy we found statistically higher cumulated cortical-subcortical lesion loads in the cases than in the controls (Wilcoxon, P = 0.036). Total lesion loads (cortical-subcortical plus deep white matter loads) did not differ significantly (P > 0.1) between cases and controls. The relative risk for seizures as determined by the odds ratio of a cortical-subcortical lesion load of > or = 20 was 8.8 (chi 2 = 5.23, P 0.025), the odds ratio of a large (> 1 cm) cortico-subcortical lesion was 4.7 (chi 2 = 4.9, P < 0.05), while the 2 MR criteria combined show an odds ratio of 19.2 (chi 2 = 8.0, P < 0.005). We conclude that: first, the presence of cortical-subcortical lesions in part accounts for the occurrence of seizures in MS patients; second, due to the substantial overlap of MR imaging scores between cases and controls the ultimate use of these MR imaging findings in the management of individual patients or in the organizations of trials should depend on the expected benefit of the treatment. If the benefit is only moderate or not known a cautious approach with exclusion of cases showing a substantial cortical-subcortical lesion load on MR imaging seems appropriate in trials with drugs, like 4-aminopyridine, that lower the epileptic threshold.

Mitochondrial defects, defects in gluconeogenesis, and biotin-responsive multiple carboxylase deficiency are disorders characterized by primary lactic acidosis. In this review, characteristic findings in magnetic resonance imaging (MRI) of the brain, as related to histopathological abnormalities, are described for the different disorders and the diagnostic value of the MRI findings is discussed. Inborn errors of metabolism with primary lactic acidosis should be considered in particular when MRI shows lesions similar to or reminiscent of effects of focal or generalized hypoxia-ischaemia, or when MRI shows signs of chronic neurodegeneration, but rarely in cases with predominantly white-matter changes.

Background: The clinical significance of anomalously originating coronary arteries depends on their proximal course. Diagnosis of this course by conventional x-ray coronary angiography alone may be equivocal. We postulated that with fast magnetic resonance (MR) angiography, accurate detection of anomalous coronary arteries and unambiguous delineation of their proximal course is feasible., Methods and Results: In a selected group of 38 patients, 19 of them having an anomalously originating coronary artery, a fast MR angiographic technique was used to study the proximal coronary anatomy. Blinded analysis of randomly ordered MR studies was performed independently by two observers. Both origin and proximal course of the coronary arteries were defined. Two cardiologists reviewed all x-ray coronary angiograms. After the separate analyses, a final consensus result was defined for each patient. In 37 patients, successful MR coronary angiography could be performed. Interobserver agreement for determining both origin and proximal course was 100%. An x-ray coronary angiogram was available in 36 patients. In 3 patients (all with an anomalous left main coronary artery originating from the right aortic sinus), there was disagreement about the proximal course between the results of MR and x-ray coronary angiography. Review of these cases demonstrated that MR angiography had unambiguously visualized the proximal coronary artery course, whereas the results of x-ray angiography had been equivocal. Thus, sensitivity and specificity for detecting anomalous coronary arteries and delineating their proximal course were 100%., Conclusions: These data suggest that fast MR angiography is highly accurate in determining the origin and delineating the proximal course of anomalous coronary arteries, even in those cases in which x-ray coronary angiographic diagnosis is difficult or even erroneous.

In children, several neurological disorders are characterised by spongiform leukoencephalopathy. MRI of the brain typically shows white matter swelling, but does not enable differentiation of the various underlying disorders. The aim of this article is optimisation of the diagnostic value of MRI in leukoencephalopathy accompanied by swelling. MRI-based inclusion criteria were met by 20 patients in our database. The images were analysed using a detailed scoring list. In 13 of the 20 patients the clinical diagnosis was known (11 definite and 2 probable diagnoses). Characteristic MRI abnormalities could be defined in these patients. Of the 7 patients without a diagnosis, 5 had identical MRI abnormalities: diffuse hemisphere swelling and typical cysts in frontoparietal subcortical white matter and the tips of the temporal lobes. The clinical picture was also similar in these patients, suggesting a similar disease.

The purpose of this study was to investigate the feasibility of first-pass MR imaging for measurement of regional myocardial blood flow in human beings. The first pass of the contrast agent Gd-DTPA through the myocardium was imaged in 12 normal volunteers with an ECG-gated Turbo-Flash sequence. The MTT of the contrast agent through the myocardium after a bolus injection was derived from curves of SI versus time. The bolus was injected through an intravenous catheter, which was advanced to the central venous position (preferably the right atrium). To investigate myocardial input function, different bolus concentrations and catheter positions were compared. It is concluded that first-pass MR imaging is feasible in human subjects when a central injection of 0.03 mmol/kg of Gd-DTPA is applied. MTT values were similar throughout the myocardium of normal subjects at rest, reflecting normal perfusion. Absolute values of MTT were related to the myocardial input.

Magnetic resonance imaging (MRI) is being used as an outcome criterion in therapeutic trials in multiple sclerosis (MS) on the assumption that it, as a sensitive marker of biologic disease activity, could serve as a surrogate marker of disability. We evaluated the relation between MRI findings and disability in a quantitative follow-up study of 48 MS patients. Median duration of follow-up was 24 months (range, 10 to 42 months). Computer-assisted volume measurements employing a seed-growing technique yielded a standard error of measurement of 0.275 cm2. The median total area of the hyperintense lesions on the initial T2-weighted images was 8.4 cm2. The median increase was 0.76 cm2/yr (9%). In a subgroup (n = 19) with short-TR/short-TE spin-echo (SE) images, we measured the hypointense lesion load. The median total area of the lesions at entry was 0.70 cm2, with a median increase of 0.28 cm2/yr (40%). The total area of the hyperintense lesions on the initial T2-weighted images showed a weak correlation with the Expanded Disability Status Scale score at entry (Spearman rank correlation coefficient [SRCC] = 0.30; 0.02 < p < 0.05). The increase in disability showed a positive correlation (SRCC = 0.19) with the increase in hyperintense lesion load on the T2-weighted SE images, but this correlation did not reach statistical significance (p = 0.09), probably because of lack of clinical progression.(ABSTRACT TRUNCATED AT 250 WORDS)

Severe or even mild hyperhomocysteinaemia can cause a wide range of neurological problems. In recent years its vascular complications, including cerebral stroke, in children and young adults have gained special interest, because hyperhomocysteinaemia is treatable and recurrence of vascular incidents may be preventable. Current knowledge about biochemical mechanisms leading to hyperhomocysteinaemia, the pathogenesis of vascular pathology and neurological disfunction, and the various patterns of cerebral damage are reviewed. The significance of MRI in diagnosis, follow-up and research on hyperhomocysteinaemia is discussed.

The purpose of this study was to develop a standardized method of 2D MRA of the proximal 50 mm of the major epicardial coronary arteries. Therefore the efficacy of fixed imaging planes (transverse, coronal, sagittal, 30-degree RAO equivalent, and 60-degree LAO equivalent) in imaging coronary arteries was compared to that of oblique planes defined by the operator on a previously obtained image. 3D data sets obtained by a respiratory-gated 3D MRA method in eight patients with a mean age of 57 years were studied by multiplanar reformatting. Efficacy of planes was expressed as an IOE. Fixed transverse imaging planes proved to be equally efficacious as operator-defined planes in imaging the left main (IOE 2.2 +/- 1.0 vs 2.2 +/- 0.9, p = NS) and LAD (IOE 6.0 +/- 1.9 vs 8.2 +/- 2.0, p = NS). Operator-defined planes were superior to fixed imaging planes in imaging the RCA (IOE 6.3 +/- 1.2 vs 3.5 +/- 1.2, p < 0.001) and the LCx (IOE 6.2 +/- 2.3 vs 4.8 < 2.3, p < 0.05). On the basis of these results, a standardized 2D MRA protocol for the proximal coronary arteries was proposed. Pitfalls in interpretation of coronary MRA images were discussed.

Objective: The MR findings in a characteristic pattern of hypoxic-ischemic brain damage in term infants are described., Materials and Methods: The MR images of seven patients with cerebral palsy and a specific pattern of central cortico-subcortical cerebral damage were studied retrospectively and correlated with clinical findings., Results: All seven patients were born at term. Five of the seven patients had a clear history of severe perinatal asphyxia. All children had severe encephalopathic symptomatology, including spastic tetraplegia, extrapyramidal symptoms, and a mental deficit. The MR showed localized atrophy of the cortex and in addition cystic changes, gliosis, and tissue loss of the adjacent white matter. In all patients, the lesions were band shaped in the left-right direction and characteristically located in areas bordering the central sulcus. The segment of the corpus callosum underlying the affected area was always thin. In some patients, lesions were also found bilaterally in the occipital regions, hippocampus, and basal ganglia. The areas involved match the regions that are known to show active myelination on MR in the term neonate., Conclusion: Recognition of this specific pattern on MR in children with cerebral palsy enables the classification of such lesions as resulting from peri- or postnatal asphyxia, even if the perinatal history is unknown or equivocal, and makes other etiologies less likely.

An identical syndrome of cerebral leukoencephalopathy and megalencephaly with infantile onset was discovered in 8 children, including 2 siblings. Neurological findings were initially normal or near normal, despite megalencephaly and magnetic resonance imaging (MRI) evidence of severe white matter affection. Slowly progressive ataxia and spasticity developed, while intellectual functioning was preserved for years after onset of the disorder. MRI characteristics included diffuse abnormality in signal intensity and swelling of the cerebral hemispheral white matter with cyst-like spaces in the frontoparietal and anterior-temporal subcortical areas. MR spectra were relatively mildly abnormal. Screening for inborn errors, especially those that cause either megalencephaly or white matter disease or both was negative. A distinguishing feature of the present disorder is the apparently severe abnormality of the cerebral white matter as demonstrated by MRI, which contrasts with the remarkably slow course of functional deterioration.

Purpose: To determine whether gadolinium can improve the sensitivity and specificity of MR imaging for the initial diagnosis of multiple sclerosis., Methods: Patients (n = 57) with neurologic symptoms suggesting multiple sclerosis were studied prospectively. MR imaging consisted of T2-weighted and gadolinium-enhanced T1-weighted spin-echo images. Lumbar puncture was performed for cerebrospinal fluid analysis in 34 patients., Results: After imaging, 17 patients (35%) had clinically definite multiple sclerosis. Cerebrospinal fluid examination had a sensitivity of 69% and specificity of 38%. Using liberal criteria, the sensitivity of T2-weighted MR imaging was 94% and the specificity 55%; using more strict criteria, the specificity increased to 65% with a sensitivity of 88%. Gadopentetate dimeglumine enhancement increased the specificity further to 80% with a loss of sensitivity (59%)., Conclusion: Gadolinium enhancement increases the specificity of MR imaging in the early diagnosis of multiple sclerosis.

The syndrome of autosomal recessive pontocerebellar hypoplasia, microcephaly, severely impaired mental and motor development, and extrapyramidal dyskinesia is a distinct system degeneration, previously designated pontocerebellar hypoplasia type 2 (PCH-2). To further characterize its clinical and neuroimaging features, we compiled data from 10 nonrelated pedigrees. Six pedigrees were Dutch, two Swedish, and two German. All 16 patients showed an identical profile of virtually absent developmental milestones, early-onset severe chorea, and microcephaly together with pontocerebellar hypoplasia. Family distribution supports autosomal recessive transmission. The present data support the PCH-2 phenotype as a distinct neurogenetic entity.

Fluid attenuated inversion recovery (FLAIR) sequences produce selective cerebrospinal fluid (CSF) suppression by employing a very long inversion time (TI). We used the FLAIR sequence to study patients with multiple sclerosis (MS) at 0.6 T. So far, a very long TR (and long acquisition time) has been used in a fully relaxed (FR-FLAIR) system. To speed up the FLAIR sequences, we used a shorter TR, and demonstrated that complete CSF suppression can be maintained with partial saturation (PS-FLAIR) by reducing TI at the same time. The introduction of partial saturation, however, reduced the contrast between lesions and normal appearing white matter (NAWM). Suboptimal CSF suppression therefore had to be accepted to maintain sufficient lesion to NAWM contrast. Using a TE of 60 ms, the PS-FLAIR and FR-FLAIR performed equally well in the detection of MS-lesions, although the former provided poorer CSF suppression. Both FLAIR sequences, however, provided poorer constrast between lesions and NAWM compared to conventional spin-echo sequences. Although the long acquisition time of the FLAIR sequence can be reduced by using partial saturation, complete CSF suppression and good lesion to NAWM contrast are incompatible at short TRs. Using a TE of 60 ms, conventional spin-echo sequences detect more lesions and provide better contrast between lesions and NAWM than FLAIR sequences in MS patients.

From April 1992 to January 1993, radiology expert opinion for MRI procedures was offered by means of teleradiology. The experiment was carried out in addition to an existing service of a mobile MRI unit. MRI images were sent by means of teleradiology via regular telephone lines from the mobile MRI unit to an academic hospital, which served as expert consultation centre. During this period, 43 requests for expert opinions were performed. This article describes the clinical effects of these expert opinions, and the technical and organisational requirements to perform teleradiology in daily clinical practice.

Purpose: To determine the frequency of appearance of various MR signs in mesial temporal sclerosis, to determine the optimal scanning planes for their visualization, and to propose a histologic explanation for the diminished demarcation between gray and white matter in the temporal lobe, a frequent MR finding in patients with mesial temporal sclerosis., Methods: MR scans of 14 surgically treated patients with epilepsy and histologically proven mesial temporal sclerosis were assessed for the presence of six features: feature 1, high signal intensity in the hippocampus; 2, reduced hippocampal size; 3, ipsilateral atrophy of the hippocampal collateral white matter; 4, enlarged temporal horn; 5, reduced gray-white matter demarcation in the temporal lobe; and 6, decreased temporal lobe size., Results: Feature 1 was present in 14 patients and was best appreciated on the T2-weighted images in planes parallel to the long axes of the hippocampi. Feature 2, present in 12 patients, and feature 6, present in 9 patients, were optimally seen in the coronal planes and on the inversion-recovery sequences in particular. Feature 3, present in 12 patients, was optimally seen on the coronal T2-weighted images. Feature 4, seen in 11 patients, was equally well seen in all planes (transverse, coronal, and parallel to the long axes of the hippocampi). Feature 5, seen in 10 patients, was best appreciated on the T2-weighted images in the planes of the long axes of the hippocampi. Histologic investigation of the temporal lobe white matter in the 10 patients with feature 5 demonstrated on the MR scan showed abnormalities in 7 cases. Oligodendroglia cell clusters were found in 6, with concomitant corpora amylacea in 1 case and perivascular macrophages with pigment a sole finding in another case., Conclusion: Of the six features found in cases of mesial temporal sclerosis on MR, increased hippocampal signal intensity is the most consistent. A decreased gray-white matter demarcation in the temporal lobe parenchyma is also a frequent feature of this disease. A combination of multiple scanning planes results in an optimal demonstration of lesions.