Browsing by Author "Du Toit, R."
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- ItemThe diagnostic accuracy of integrated positron emission tomography/computed tomography in the evaluation of pulmonary mass lesions in a tuberculosis-endemic area(Health and Medical Publishing Group, 2015) Du Toit, R.; Shaw, J. A.; Irusen, E. M.; Von Groote-Bidlingmaier, F.; Warwick, J. M.; Koegelenberg, C. F. N.Background. Integrated positron emission tomography/computed tomography (PET-CT) is a well-validated modality for assessing pulmonary mass lesions and specifically for estimating risk of malignancy. Tuberculosis (TB) is known to cause false-positive PET-CT findings. Objective. To investigate the utility of PET-CT in the evaluation of pulmonary mass lesions and nodules in a high TB prevalence setting. Methods. All patients referred for the evaluation of a solitary pulmonary nodule or mass and who underwent PET-CT scanning over a 3-year period were included. The PET-CT findings, including maximum standardised uptake value (SUVmax), were compared with the gold standard (tissue or microbiological diagnosis). The sensitivity, specificity, positive and negative predictive values and diagnostic accuracy for malignant disease were calculated according to the SUVmax cut-off of 2.5 and a proposed cut-off obtained from a receiver operating characteristic (ROC) curve. Results. Forty-nine patients (mean (standard deviation) age 60.1 (10.2) years; 29 males) were included, of whom 30 had malignancy. Using an SUVmax cut-off of 2.5, PET-CT had a sensitivity, specificity, positive and negative predictive value and diagnostic accuracy for malignancy of 93.3%, 36.8%, 70.0%, 77.8% and 71.4%, respectively. After a ROC curve analysis, a suggested SUVmax cut-off of 5.0 improved the specificity to 78.9% and the diagnostic accuracy to 86.7%, with a small reduction in sensitivity to 90.0%. Conclusions. The diagnostic accuracy of PET-CT in the evaluation of pulmonary mass lesions using the conventional SUVmax cut-off of 2.5 was reduced in a TB-endemic area. An SUV cut-off of 5.0 has a higher specificity and diagnostic accuracy for malignancy, with a comparable sensitivity.
- ItemFrequent fetal heart-rate monitoring for early detection of abruptio placentae in severe proteinuric hypertension(Health & Medical Publishing Group, 1988) Odendaal, H. J.; Pattinson, R. C.; Du Toit, R.; Grove, D.Abruptio placentae occurred in 16 of 132 patients with severe pre-eclampsia who were admitted to an obstetric high-risk ward before 34 weeks' gestation. These 16 patients were compared with those who did not develop abruptio placentae. Systolic and diastolic blood pressure levels, proteinuria and birth weights did not differ significantly between the two groups. Apgar scores were significantly lower in the abruptio placentae group. There were 6 intra-uterine and 2 neonatal deaths in the abruptio placentae group (50% perinatal mortality (PNM)) and 3 intra-uterine and 16 neonatal deaths in the other group (18% PNM). Four patients with abruptio placentae presented with abnormal fetal heart-rate patterns and 8 with abdominal pain. No warning signs were present in 3 patients and the fetal heart-rate pattern before delivery was not available in 1 patient. Abnormal fetal heart-rate patterns were present in 5 of the 8 patients who presented with pain. Abruptio placentae occurring in patients with severe proteinuric hypertension carries a high PNM. Frequent monitoring of the fetal heart rate sometimes helps to diagnose fetal distress before the clinical signs of abruption become apparent.
- ItemMitral valve apparatus : echocardiographic features predicting the outcome of percutaneous mitral balloon valvotomy(Clinics Cardiv Publishing, 2007-06) Du Toit, R.; Brice, E. A. W.; Van Niekerk, J. D.; Doubell, A. F.Objectives: To evaluate the significance of involvement of subvalvular apparatus in the outcome of percutaneous mitral balloon valvotomy (PMBV) in patients with mitral stenosis (MS) and to determine the predictive value of chordal length compared with current echocardiographic scores. Methods: Patients with significant MS were selected according to the Massachusetts General Hospital score (MGHS). Chordal lengths were assessed as additional markers of disease. Standard percutaneous valvotomies were performed. Valve area was assessed post-procedure with follow-up over one year. Results: Thirty-nine patients were prospectively studied. Valve area increased from a mean (SD) 0.97 (0.26) cm² to 1.52 (0.38) cm² with procedural success in 31 (79.5%) patients. There was no correlation (r = 0.09) between the MGHS and final valve area (FVA). There was a positive correlation between anterior chordal length and FVA (r = 0.66; p = 0.01). An FVA ≥ 1.5 cm² was associated with higher mean chordal lengths (p = 0.01). A positive correlation was seen between valve area pre-procedure and FVA (r = 0.61; p < 0.01). Conclusions: The MGHS is valuable in the selection of patients for PMBV, but fails to separate selected patients into prognostic groups. Assessment of chordal length provides useful additional information, predicting the outcome of PMBV more accurately. Our data may support the earlier use of PMBV (asymptomatic patients).
- ItemThe use of the polymerase chain reaction test in the diagnosis of tuberculosis(Health & Medical Publishing Group, 1991) Van Helden, P. D.; Du Toit, R.; Jordaan, A.; Taljaard, B.; Pitout, J.; Victor, T.Current techniques for laboratory diagnosis of tuberculosis have some serious limitations. These include the high cost and time required for the current assays. The development of a rapid, sensitive, specific and low-cost assay is therefore of considerable importance. We report here the development and laboratory testing of a polymerase chain reaction DNA-based diagnostic test for the presence of Mycobacterium tuberculosis in sputum. The assay shows a high level of sensitivity and specificity and requires considerably less capital, consumables and time inputs than existing laboratory tests. We believe this technology is ready for large-scale evaluation and use, particularly in hospital-based laboratories.