MR evaluation of the articular cartilage of the femoral head during traction. Correlation with resected femoral head

As a result of a high percentage of hypoactive upper poles of kidneys in traditional 99mTc-dimercaptosuccinic acid (DMSA) SPECT, a prospective study was conducted using 180 degrees acquisition technique compared with 360 degrees to minimize tissue attenuation. METHODS: Anterior 180 degrees, posterior 180 degrees and 360 degrees renal SPECT images were obtained simultaneously using a dual-head camera. Forty-one subjects without renal disease and 16 subjects with 21 cortical defects were included in this study. The total counts of the raw data in the anterior 180 degrees, posterior 180 degrees and full 360 degrees were calculated. Small regions of interest were drawn over the cortex of the kidney on coronal and reoriented sagittal slices. Quantitative evaluation of regional activity was performed on the same frames in all three acquisition methods. RESULTS: Comparison of the total renal counts between the anterior and posterior 180 degrees data showed reduced counts in the anterior 180 degrees data collection (P < 0.01). Visual evaluation of the reconstructed images from anterior 180 degrees, posterior 180 degrees and full 360 degrees data collection showed the best image uniformity in the posterior 180 degrees image. The upper/lower pole ratio in the posterior 180 degrees renal SPECT images increased significantly in comparison to full 360 degrees renal SPECT images (P < 0.01) and anterior 180 degrees SPECT images (P < 0.01). The renal defects were more clearly visualized in the posterior 180 degrees renal SPECT images than the full 360 degrees renal SPECT images. The defect/normal cortex ratios in the posterior 180 degrees renal SPECT images were much lower than those from the full 360 degrees SPECT images (P < 0.01) and those from the anterior 180 degrees SPECT images (P < 0.01). CONCLUSION: The posterior 180 degrees acquisition technique can avoid the problem of hypoactive upper pole and can be less time consuming in 99mTc-DMSA SPECT images. It also provides superior lesion contrast in the clinical evaluation of patients with renal scarring.