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Biomedical subjects

M Olree

Publications and source records attributed to M Olree.

8 recordsLinked to original sources
PubMed1999

Renal volume measurements: accuracy and repeatability of US compared with that of MR imaging.

PURPOSE: To determine the accuracy and repeatability of ultrasonography (US) with the ellipsoid formula in calculating the renal volume. MATERIALS AND METHODS: The renal volumes in 20 volunteers aged 19-51 years were determined by using US with the ellipsoid formula and magnetic resonance (MR) imaging with the voxel-count method by two independent observers for each modality. The observers performed all measurements twice, with an interval between the first and second examinations. The voxel-count method was the reference standard. Repeatability was evaluated by calculating the SD of the difference (method of Bland and Altman). RESULTS: Renal volume was underestimated with US by 45 mL (25%) on average. A comparable underestimation was found when the ellipsoid formula was applied to MR images. This indicates that the inaccuracy of US renal volume measurements (a) occurred because the kidney does not resemble an ellipsoid and (b) was not primarily related to the imaging modality. Intra- and interobserver variations in US volume measurements were poor; the SD of the difference was 21-32 mL. For comparison, the SD of the difference in reference-standard measurements was 5-10 mL. CONCLUSION: Use of US with the ellipsoid formula is not appropriate for accurate and reproducible calculation of renal volume.

Adult↗
PubMed1998

In vitro measurement of kidney size: comparison of ultrasonography and MRI.

In this in vitro study, the accuracy and repeatability of magnetic resonance imaging (MRI) and ultrasound (US) in assessing renal length and volume were determined. US and MR images of 20 cadaver pig kidneys were obtained twice and evaluated by two observers for each modality. The fluid displacement method provided the "gold standard." Renal volumes were calculated from the US and MR images using the ellipsoid formula. Additional volume calculations after segmentation of the kidney on MR images were done using the voxel-count method. Volumes calculated with the ellipsoid formula resulted in an average of 24% underestimation (range 5%-48%) of the renal volume for both US and MRI. With the voxel-count method, no significant deviation from the true renal volume was encountered. Repeatability was also greatest with the voxel-count method. Measuring renal length, repeatability was, again, better with MRI compared to US. For reliable calculation of renal size in vitro, MRI with use of the voxel-count method is preferred.

Animals↗
PubMed1997

Preoperative sizing of grafts for transfemoral endovascular aneurysm management: a prospective comparative study of spiral CT angiography, arteriography, and conventional CT imaging.

PURPOSE: To define the impact of spiral computed tomographic angiography (CTA) with image reconstruction on graft selection for Transfemoral Endovascular Aneurysm Management (TEAM) by comparing it to conventional computed tomography (CT) and contrast arteriography. METHODS: Twenty-one candidates for TEAM were included. The diameters of the superior and inferior aneurysm necks and lengths between the graft attachment sites were measured using the three imaging techniques. These measurements and their consequences on graft selection were studied. RESULTS: The difference in length sizing between spiral CTA and arteriography never exceeded 1 cm; however, lengths measured by conventional CT scanning resulted in underestimation of graft length in 91% of patients. Graft diameters were chosen too small in 62% of the patients when based on arteriographic diameter measurements. A graft of similar diameter was selected by spiral CTA and conventional CT scanning in 81% of the patients, while minor oversizing by conventional CT scanning was found in 14%. CONCLUSIONS: Neither conventional CT scanning nor arteriography is adequate as a sole preoperative radiological investigation for TEAM graft sizing. Spiral CTA with image processing produces all information required for selection of the optimal graft size and should be regarded the method of first choice for this purpose.

Aged↗
PubMed1993

Patient-controlled analgesia (PCA) leads to more postoperative pain relief, but also to more fatigue and less vigour.

This investigation evaluated patient-controlled analgesia (PCA) for subjective well-being and mood in the postoperative period in comparison with the intramuscular (im) administration of morphine given on demand. Patients scheduled for elective upper abdominal surgery were assigned at random to either PCA (n = 17) or im morphine (n = 14). The PCA group experienced significantly more pain relief and consumed more morphine than those who received im morphine. The PCA patients suffered from more fatigue and showed less vigour than the im group. Neither preoperative trait anxiety nor locus of control was associated with postoperative pain in either of the groups.

Adult↗