MRI of the brain in HIV-positive patients: what is the value of routine intravenous contrast medium?

Our purpose was to assess the value of routine administration of intravenous gadolinium-DTPA (Gd-DTPA) for cranial MR in a series of human immunodeficiency virus (HIV)-positive patients. Two radiologists retrospectively reviewed 150 consecutive examinations of 104 patients. All patients underwent unenhanced and contrast-enhanced images. Each radiologist independently assessed first the unenhanced images alone and then the pre- and postinjection images together. Then both reviewed the complete study and produced a consensus report. The history, investigations and management were collated separately and were unknown to the radiologists. Contrast-enhanced T1-weighted images showed new focal abnormalities, not seen on the T2-weighted or unenhanced images in 15 (14 %) patients, but almost always in the context of abnormal unenhanced images. In only 2 patients (2 %) did contrast medium reveal abnormalities when the unenhanced study had been considered normal. In only 1 of these (1 %) was the new finding, cytomegalovirus diffuse ependymal enhancement, of clinical importance, although the diagnosis of encephalitis was made on routine examination of cerebrospinal-fluid. The other revealed a toxoplasma lesion in a patient known to have resolving disease. Meningeal disease not suspected on the unenhanced images was shown in 2 patients (2 %). In these case the unenhanced images were abnormal in other respects. Intravenous Gd-DTPA was helpful to the radiologist in making a radiological diagnosis in 11 patients (11 %), usually by improving characterisation of a lesion seen on the unenhanced images. The contribution of intravenous Gd-DTPA in this series does not warrant recommending its use in every case.

Moyamoya disease.

Moyamoya disease is a rare cerebrovascular condition of uncertain aetiology commonly affecting young persons. The disease is mainly seen in Japanese patients. We report two cases of moyamoya disease in Caucasian women and review the postulated aetiological factors and associated conditions as well as the spectrum of invasive and non-invasive imaging modalities useful in the diagnosis and follow-up of the disease, with particular reference to the developing role of magnetic resonance imaging and angiography.

Magnetic resonance renography: optimisation of pulse sequence parameters and Gd-DTPA dose, and comparison with radionuclide renography.

The aim of this study was to assess the feasibility of magnetic resonance renography (MRR) using gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) in comparison with conventional radionuclide renography (RR) using technetium-99m-DTPA (99mTc-DTPA). MRR has many advantages over RR, including lack of ionising radiation, increased spatial resolution, and visible background anatomy. By optimising the pulse sequence, we developed an MRR protocol in which signal intensity is linear with Gd-DTPA concentration over a clinically relevant range. Twenty-nine patients and a volunteer were studied using this protocol. Magnetic resonance renography was performed using three different doses of Gd-DTPA: 0.1 mmol kg-1 (n = 13), 0.05 mmol kg-1 (n = 7), and 0.025 mmol kg-1 (n = 9). Each patient was also assessed using radionuclide renography. The resulting renograms were assessed in terms of time to peak signal intensity, signal decrease after peak, and kidney function ratios calculated from both the areas underneath and the slopes of the uptake curves. We have shown that the MR renograms obtained using low dose Gd-DTPA correlate best with the radionuclide renograms. Remaining discrepancies may be explained by variations in the injection procedures (hence in arterial input functions) and the limited coverage of the three MRR slices compared to the whole body projection of RR. Furthermore, at high local concentrations, signal becomes independent of T1 and is dominated by T2.

Longitudinal field investigation of the moderating and mediating effects of self-efficacy on the relationship between training and newcomer adjustment.

A longitudinal field study examined the moderating and mediating effects of self-efficacy on the relationship between training and the adjustment of newcomers during their 1st year of employment. The results provided some support for the hypothesis that initial self-efficacy moderates the relationship between training and adjustment. Training was more strongly related to posttraining self-efficacy, ability to cope, job performance, and intention to quit the profession for newcomers with low levels of initial self-efficacy mediates the relationship between training and adjustment; however, evidence of complete mediation was found only for ability to cope. Posttraining self-efficacy partially mediated the relationships between training and job satisfaction, organizational and professional commitment, and intention to quit the organization and the profession. Research and practical implications of these findings for the training and the socialization of newcomers are discussed.

Improved MR venography: use of fast short inversion time inversion-recovery technique in evaluation of venous angiomas.

Eleven patients (five female and six male, aged 6-67 years) with venous angiomas underwent axial and coronal T1-weighted and fast short inversion time inversion-recovery (STIR) magnetic resonance (MR) imaging to assess the full extent of the malformations. Images were assessed subjectively by the authors in a nonblinded study. In all patients, fast STIR images depicted more anatomic detail than did T1-weighted images and depicted venous angiomas more clearly than did contrast material-enhanced CT scans but did not help discrimination of arteries and veins.

Tuberculosis in HIV positive patients in South Africa: a comparative radiological study with HIV negative patients.

The radiological appearances of active tuberculosis in human immunodeficiency virus (HIV) positive patients was reviewed. A study group of 61 Black HIV positive patients and a control group of 50 Black HIV negative patients were analysed. The chest radiographs of the HIV seropositive group showed a significantly higher percentage of lymphadenopathy (50%), pleural effusions (38%) and miliary (8%) or interstitial patterns (11%), as compared with those in the seronegative group (8%, 20%, 0% and 4% respectively). Cavitation (38%) and atelectasis (31%) were less common in the seropositive group than in the seronegative group (82% in each category). Thus in an endemic TB environment an awareness of this difference in appearances will allow the radiologist to alert the referring clinician to the possibility of concomitant HIV seropositivity.

[Results of prospective cytological diagnoses of cervical intraepithelial neoplasia]. / Rezultati prospektivne citoloske dijagnoze cervikalne intraepitelne neoplazije.

The value of prospective cytologic diagnosis in cervical intraepithelial neoplasia (CIN) is analysed by means of ROC (receiver operating characteristic) curves. Examined was a group of 160 women with subsequent cone biopsies. The result of a prospective cytologic diagnosis in moderate dysplasia, severe dysplasia and carcinoma in situ is analysed separately, taking into consideration the particular frequencies in the studied group. The most reliable prospective cytologic diagnosis is in moderate dysplasia, followed by carcinoma in situ a slightly more reliable prospective diagnosis than that in severe dysplasia.

[Evaluation of the value of ultrasound in the diagnosis of gynecologic tumors]. / Ocjena vrijednosti ultrazvuka u dijagnostici ginekoloskih tumora.

The value of ultrasound (US) is analysed by means of ROC-curves (receiver operating curves) taking into consideration both the sensitivity and specificity of the method, as well as the prevalence of particular tumours in the examined group. US diagnosis is compared with clinical and surgical findings. The authors have found that the degree of reliability achieved by either the clinical or the US method of diagnosing myomas is almost the same. In the diagnosis of benign cysts and carcinomas, however, US has more advantages.