Gadolinium enhancement: improved MRI detection of retinoblastoma extension into the optic nerve

We performed T1-, T2-, proton density-weighted, and T1-weighted gadolinium-enhanced MRI on 24 patients with retinoblastoma, using a 1.5 T superconducting unit and head and orbital surface coil imaging. All patients underwent a complete ophthalmologic examination, including B-scan ultrasonography. CT was performed on 10 of 24 patients. Pathologic correlation was obtained in 18 patients who required enucleation. Contrast-enhanced T1-weighted MRI with fat suppression was the sequence most sensitive to optic nerve extension and provided the greatest differentiation between tumor and uninvolved extrascleral tissue. Retinoblastoma demonstrated contrast enhancement.     

Optic nerve dysplasia associated with meningeal defect in Sprague-Dawley rats

The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine (123I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of 123I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of 123I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). 123I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data [left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)], plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data [mean low frequency (MLF) and high frequency power (MHF)] and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of 123I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the 123I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure.     

Varicella zoster virus retrobulbar optic neuritis preceding retinitis in patients with acquired immune deficiency syndrome

A 10-year-old girl with lupus vulgaris following single BCG vaccination is reported. She had a 15 x 20 cm painless lesion covering her left shoulder, axilla, triceps and biceps region. PPD test was positive. Histopathological picture was identical to lupus vulgaris.     

Further evidence of acoustic invariance in speech production: the stop-glide contrast

We have conducted a detailed comparative acoustic analysis of the labial stop and glide, [b] and [w], and we have attempted to identify an invariant acoustic property which can accurately distinguish stops and glides. To this end, we conducted three experiments. In experiment I, we undertook computer analysis of the labial stop [b] and the labial glide [w] as produced in five vowel contexts by two speakers. Results indicated that transition durations and formant frequencies often differed considerably in these two classes of sounds--and to a much greater extent than suggested in previous perception experiments. In experiment II we examined a measure of amplitude--unit energy. We calculated the degree of relative amplitude change occurring in the vicinity of the stop and glide release and found reliably larger changes in energy associated with the stop release than the glide release across vowel contexts and speakers. These changes seemed to provide an invariant property characterizing the stop--glide contrast. In experiment III we tested the generality of our claims by examining a new set of data consisting of the stops [d] and [g] and the glide [y]. Results of this experiment further supported our hypothesis. We have related our findings to a general theory of acoustic invariance in speech.     

Precipitation of a cholegraphic contrast medium in a dog

Following intravenous injection of medium for cholegraphy, calcium salt was precipitated in the tubules of rats and a 'gallstone' containing contrast medium developed in a dog. A review is given of biotransformation of contrast media in the biliary and urinary tracts.     

Follow-up study in patients with neuritis retrobulbaris (author's transl)

In 11 patients with multiple sclerosis (MS) and eight patients in whom MS was not verified visus, computerized perimetry, bipolar flash evoked cortical potential (H-EP) and pattern-reversal evoked cortical response (M-EP) were recorded in the acute stage and convalescent period of neuritis retrobulbaris. In the acute stage visual field deficiencies, diminutions of H-EP and M-EP amplitudes and increases in H-EP latencies were seen in both eyes in all cases. The most severe pathologic changes were found in the worst eyes in the group without MS. In the convalescent period a complete restitution of the electro-ophthalmological parameters was found in neither group of patients by statistical methods. Restitution was more common in patients who were not suffering from MS.     

Cytokine production and the pathogenesis of experimental autoimmune neuritis and Guillain-Barré syndrome

Acute inflammatory demyelinating polyradiculoneuropathy (Guillain-Barré syndrome, GBS) and its animal model experimental autoimmune neuritis (EAN) are prototypes of T cell-mediated autoimmune diseases affecting the peripheral nervous system (PNS). Perivascular accumulation of macrophages and T lymphocytes in the PNS, and high levels systemically of PNS myelin antigen-reactive T cells are characteristic features of both diseases, thereby suggesting a pathogenic role for immunoregulatory cytokines. Here we summarise recent studies that have clearly documented that Th1/Th2/Th3 cytokines are differently upregulated during various clinical phases of EAN and GBS. The observations indicate that the role of cytokines in immune regulation and autoimmune disease is more complex than a simple Th1-Th2 dichotomy would suggest. New treatments may be searched for that counteract this complex cytokine imbalance. Treatments with antibodies that selectively target certain pro-inflammatory cytokines, as well as with immunomodulatory preparations that promote cytokines that beneficially influence the disease course should be in focus of future therapeutic trials.     

The size of acoustic neuromas: CT and MRI

The growth rate of acoustic neuromas is very variable: some tumours grow rapidly, some do not grow and some even get smaller. When making treatment decisions, it may be important to have an idea of the growth rate of the individual tumour, and this is only possible when there are comparable examinations. We performed both CT and MRI on 15 patients. Two radiologists estimated the size of their acoustic neuromas. There was a significant difference between the two examiners' calculations of tumour volumes on CT and between the first examiner's CT and MRI volume calculations. No difference was found between the two MRI volume estimations or the second examiner's estimation of volumes on CT and MRI. Measurements of the maximal tumour diameter along the pyramid showed good concordance. We conclude that measurement the size of acoustic neuromas is reproducible with MRI and the measurement of the maximal tumour diameter is in practice a better parameter for comparison than calculation of real volume.     

Safe amounts of contrast medium for angiocardiography in neonates and infants

The results were analysed of 485 (biplane) cineangiocardiograms performed in 200 consecutive cardiac investigations on neonates (under 4 wk) and infants (4 wk to 1 yr). 10 deaths occurred during or within 24 h of cardiac catheterization, all in patients who were profoundly acidemic because of their hemodynamic disturbance. A total dose of Cardio-Conray at any one investigation of 4-5 ml/kg body weight was satisfactory and without undue risk. Single injections of 1.5-2.0 ml/kg body weight were safe whilst providing optimal diagnostic information. The interval between multiple injections did not appear to affect the risk to the patients.     

Improvement of lesions shown on MRI and CT scan by administration of dichloroacetate in patients with Leigh syndrome

Brain lesions exhibited on MRI and CT scan in 2 patients with mitochondrial encephalomyelopathy representing Leigh syndrome were improved by administration of dichloroacetate (DCA). One patient had pyruvic acid dehydrogenase complex (PDHC) deficiency, the other had complex I deficiency. The efficacy of DCA was transient in the patient with the PDHC deficiency, lasting for about 2.5 months. The patient died at the age of 6, about 2 years after the initiation of DCA treatment. DCA administration was started in the patient with complex I deficiency when he was 15 months old and it is still effective at his present age of 24 months. His motor ability is developing, and he could walk without support at the age of 19 months. DCA administration should be tried in patients with mitochondrial diseases.     

Preservation of cranial nerve function after treatment of acoustic neurinomas with fractionated stereotactic radiotherapy. Preliminary observations in 26 patients

Twenty-seven acoustic tumors in 26 patients were treated with multiple fractionated linear-accelerator-based stereotactic radiotherapy (SRT). All patients with intact pretreatment facial nerve function with either small or large tumor volumes have thus far experienced no treatment-related facial neuropathy, including 9 patients with a mean follow-up of 22.4 +/- 1.6 months. The incidence of evaluable trigeminal neuropathy was 13%, and in 5 of 7 patients with serviceable pretreatment hearing, audiometry was unchanged in the immediate posttreatment period. Longer follow-up will be necessary to evaluate hearing preservation after SRT. Tumor response with central necrosis was seen in all assessable patients. SRT can be performed for cerebellopontine angle tumors with accuracy and reproducibility. It achieves a biological response similar to single fraction radiosurgery and may lower the incidence of facial and trigeminal neuropathies.     

Experiences with gadodiamide, a non-ionic contrast agent, in MRI of brain metastases

29 patients suffering from brain metastases were studied with a single (0.1 mmol/kg body weight) and triple dose (0.3 mmol/kg) of gadodiamide, a non-ionic MR contrast agent. The study was performed using an extended imaging protocol with application of T1-weighted images in three orientations. Number of definite and suspected metastases, lesion contrast, edema delineation, and flow artefacts were evaluated. Most of the definite metastases were found in triple dose images. However, the total lesion number could only be determined by looking on all sequences as a whole. Furthermore, the number of suspected metastases could be significantly reduced with triple dose images, but once more all sequences were needed to do so. Flow artefacts were significantly increased by triple dose, whereby lesion contrast and edema delineation was considerably improved. The conclusion is that the combination of high dose application of the contrast agent and an optimized imaging protocol facilitates sufficient imaging of brain metastases. This is important for therapeutical considerations, because patients with more than 1-2 metastases will be treated primarily with radiation therapy instead of neurosurgery.     

Air contrast colon examination in patients with colostomies

A readily feasible technique for producing an excellent air contrast examination of the colon in patients with colostomies is described. The technique employes no special equipment and is easily tolerated by patients. Indications for the examination include a symptomatic patient with a negative conventional enema or suspicious single column examination. The surprisingly high incidence of both benign and malignant coexisting colonic neoplasms is reviewed.     

Computerized evaluation of tumor volume with MRI. Applications to the surveillance of acoustic neurinoma

Routine volume measurement techniques most often produce a rough approximate with poor accuracy for smaller structures. The results are generally improved by increasing the examination time, so that the technique then becomes unusable in daily practice. We propose a semiautomated volume calculation method with MRI, and its application to the surveillance of non-operated acoustic neuromas. This calculation technique, based on a threshold-setting method, allows accurately delineating the contours of the structures to be measured on each section and quickly calculating the total volume. After testing its reliability on control volumes, this techniques has been used to assess the evolutive nature of 16 acoustic neuromas with mild symptoms in 15 patients rejected for surgery. The radiological examinations were 428 days apart in average. On the basis of the obtained results, a theoretic tumor doubling time was calculated, thus allowing comparison between all patients. All controlled neuromas had a theoretic doubling time ranging from 427 to 4,884 days, corresponding to little- or non-evolutive lesions, which may be explained by the series selection bias excluding evolutive tumors referred to surgery. Owing to its rapidity and easy use, this semiautomated volume calculation technique for MRI seems to be very interesting as it allows reliably quantifying a volume variation that is usually estimated approximately.