Brain MR examinations were performed on one normal and 30 abnormal neonates and infants with a variety of clinical problems using pulsed gradient spin echo (PGSE) sequences sensitized in different ...directions to detect changes due to anisotropically restricted diffusion of water within the brain. Anisotropically restricted diffusion was demonstrated within white matter, which appeared to be myelinated with T1-weighted inversion recovery or spin echo sequences and within white matter where the presence of myelin was not demonstrated with these sequences. Cysts and fluid collections were recognised by their low signal intensity using PGSE sequences in the subcortical regions, lentiform nuclei, and periventricular regions. An intracerebral hematoma and a subdural hematoma showed a high signal intensity with PGSE sequences consistent with isotropically restricted diffusion. Chronic infarction displayed a low signal intensity consistent with relatively free isotropic diffusion. Patients with leukodystrophy associated with congenital muscular dystrophy showed an anisotropic pattern with different components of the abnormality present on images with sensitization in different directions. The corticospinal tracts failed to show highlighting in three cases where conventional imaging was normal. In several patients with a history of birth asphyxia, asymmetry and a relative reduction in signal intensity were seen in the corticospinal tracts.
The curative potential of radiotherapy (RT) alone as initial treatment for patients with Stage I-II lymphocyte-predominant Hodgkin lymphoma (LPHL) has not been defined well.
Two hundred two patients ...who were treated between 1969 and 1995 were evaluated in a retrospective, multicenter study.
Patient characteristics were as follows: The median age was 31 years, 75% of patients were male, 80% of patients had Ann Arbor Stage I disease, 1% of patients had bulky disease, 3% of patients had B symptoms, 1% of patients had extranodal involvement, and 80% of patients had supradiaphragmatic disease. The RT fields were a full mantle field in 52% of patients, less than a full mantle field in 24% of patients, an inverted-Y field in 17% of patients, less than an inverted-Y field in 3% of patients, and total lymph node irradiation in 3% of patients. The median dose was 36 Gray. The median follow-up was 15 years. The overall survival (OS) rate at 15 years was 83%, and freedom from progression (FFP) was observed in 82% of patients, including 84% of patients with Stage I disease and 73% of patients with Stage II disease. No recurrent LPHL and only 1 patient with non-Hodgkin lymphoma (NHL) were reported after 15 years. Adverse prognostic factors that were identified on multifactor analysis were as follows: for OS, age 45 years or older (P < 0.0005), the presence of B symptoms (P = 0.002), increasing number of sites (P = 0.015); for FFP, increasing number of sites (P = 0.002). No significant difference was found in FFP in a comparison of patients who received elective mediastinal RT with patients who did not receive mediastinal RT (P = 0.11). Causes of death at 15 years were LPHL in 3% of patients, NHL in 2% of patients, in-field malignancy in 2% of patients, in-field cardiac/respiratory in 4% of patients, and other in 6% of patients.
The current data suggested that RT potentially may be curative for patients with Stage I-II LPHL and raise the possibility that limited-field RT may be used without loss of treatment efficacy. Involved-field RT warrants further investigation for patients with early-stage LPHL.
Magnetic resonance imaging (MRI) is examined with reference to image choice and interpretation, its use in systematic disease evaluation, as well as in differential and comparative diagnosis, and new ...technical developments in this area. It is concluded that the MRI technique provides a wide variety of information whose full potential is yet to be explored. Even though the physics of image interpretation is more complex than for any other imaging technique, the multiparametric nature of MRI, its lack of ionizing radiation, and its capacity to image in any plane are likely to lead to an increasing role in medicinal diagnosis over the next decade.< >
The aim of this study was to identify prognostic factors in newborns with cerebral infarction.
Antenatal and perinatal factors and early clinical, electroencephalogram (EEG), and magnetic resonance ...imaging (MRI) findings were compared with neurodevelopmental outcome in 24 children with evidence of cerebral infarction on neonatal MRI.
Out of 24 infants, 19 had an infarction in the territory of a major cerebral vessel and 5 in the borderzone between cerebral arteries. Neuromotor outcome was normal in 17 and abnormal in 7 infants. Of these 7 infants, 5 infants showed a definite hemiplegia, whereas the other 2 showed some asymmetry of tone or function but no definite hemiplegia. None of the adverse antenatal or perinatal factors was significantly associated with abnormal outcome. Neonatal clinical examination was also not always predictive of the outcome. The extent of the lesion on MRI was a better predictor. In particular, it was the concomitant involvement of hemisphere, internal capsule and basal ganglia that was always associated with an abnormal outcome whereas the involvement of only one or two of the three tended to be associated with a normal outcome. EEG was also very helpful. Abnormal background activity either unilateral or bilateral was found in 6 infants and 5 out of 6 developed hemiplegia. In contrast, the presence of seizure activity in presence of a normal background was not related to abnormal outcome.
Early MRI and EEG can help to identify the infants with cerebral infarction who are likely to develop hemiplegia.
Mutations in the skeletal muscle ryanodine receptor (RYR1) gene are associated with a wide range of phenotypes, comprising central core disease and distinct subgroups of multi-minicore disease. We ...report muscle MRI findings of 11 patients from eight families with RYR1 mutations (n=9) or confirmed linkage to the RYR1 locus (n=2). Patients had clinical features of a congenital myopathy with a wide variety of associated histopathological changes. Muscle MR images showed a consistent pattern characterized by (a) within the thigh: selective involvement of vasti, sartorius, adductor magnus and relative sparing of rectus, gracilis and adductor longus; (b) within the lower leg: selective involvement of soleus, gastrocnemii and peroneal group and relative sparing of the tibialis anterior. Our findings indicate that patients with RYR1-related congenital myopathies have a recognizable pattern of muscle involvement irrespective of the variability of associated histopathological findings. Muscle MRI may supplement clinical assessment and aid selection of genetic tests particularly in patients with non-diagnostic or equivocal histopathological features.
The "magic angle" effect consists of the increase in signal intensity observed at a tendon or cartilage in a magnetic resonance image, when the tissue is oriented at an angle of approximately 55deg ...with respect to the main magnetic field B 0 . The exploitation of this phenomenon is often used to assist diagnosis of tendinous and other diseases, although practical difficulties derived from positioning target tissue at the desired orientation inside closed-bore scanners has made this exploitation hard to implement. A 3-DOF MR-compatible mechatronic system has been developed to position a variety of limbs at the magic angle inside a closed- bore scanner, actuated by a custom-developed pneumatic air motor. The system is capable of locating the desired anatomy with high accuracy, and is designed to position the target tissue at a minimal distance from the isocenter. The compatibility of the system is demonstrated, producing negligible artifacts and an insignificant reduction in signal to noise of the image. Preliminary clinical trials scanning the Achilles tendon of healthy volunteers prove the functionality of the device. An increase in signal intensity of up to 21-fold has been recorded in the tendon at the magic angle.
Intravenous Gd-diethylenetriamine pentaacetic acid was used in 16 patients to differentiate between syringomyelia, syringomyelia in association with tumor, and cystic tumor in the spinal cord. ...Contrast enhancement occurred in all 12 histologically proven cases of tumor and enabled clear demarcation of neoplastic tissue from syrinx or cyst. Eleven of the twelve tumors seen in association with spinal cord cavitation were malignant; all tumors apart from one (a schwannoma) were intramedullary in location. Enhanced scans were more helpful than unenhanced scans in diagnosing and defining the extent of tumors associated with a syrinx or cyst.
The brain has been the principal area of clinical interest in proton MR imaging since the first clinical scans in 1980. The technique has evolved rapidly and promises to supplement x-ray CT in a ...number of clinical applications. Recent research advances, such as the development of paramagnetic contrast agents, are now being applied in clinical practice and show considerable promise.
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