Purpose To evaluate the performance of an edge-based registration technique in correcting for respiratory motion artifacts in MR renographic data and to examine the efficiency of a semi-automatic software package in processing renographic data from a cohort of clinical patients. Materials and Methods The developed software incorporates an image-registration algorithm based on the generalized Hough transform of edge maps. It was used to estimate GFR, RPF, and MTT from 36 patients who underwent free-breathing MR renography at 3T using saturation-recovery turbo-FLASH. Processing time required for each patient was recorded. Renal parameter estimates and model-fitting residues from the software were compared to those from a previously reported technique. Inter-reader variability in the software was quantified by the standard deviation of parameter estimates among three readers. GFR estimates from our software were also compared to a reference standard from nuclear medicine. Results The time taken to process one patient’s data with the software averaged 12 ± 4 minutes. The applied image registration effectively reduced motion artifacts in dynamic images by providing renal tracer-retention curves with significantly smaller fitting residues (P < 0.01) than unregistered data or data registered by the previously reported technique. Inter-reader variability was less than 10% for all parameters. GFR estimates from the proposed method showed greater concordance with reference values (P < 0.05). Conclusion These results suggest that the proposed software can process MR renography data efficiently and accurately. Its incorporated registration technique based on the generalized Hough transform effectively reduces respiratory motion artifacts in free-breathing renographic acquisitions.

Glomerular filtration rate (GFR) measurements are critical in patients with hepatic cirrhosis but potentially erroneous when based on serum creatinine. New equations for estimated GFR (eGFR) have shown variable performance in cirrhotics, possibly because of inaccuracies in reference methods for measured GFR (mGFR). The primary objective was to compare the performance of 4 improved eGFR equations with a 1-compartment, 2-sample plasma slope intercept 99m Tc-DTPA mGFR method to determine whether any of the eGFR calculations could replace plasma 99m Tc-DTPA mGFR in patients with cirrhosis. The secondary objective was to test the hypothesis that mGFR using voluntary voided urine collections introduces error compared with plasmaonly methods. Methods: Fifty-four patients with hepatic cirrhosis underwent mGFR determinations from 2 plasma samples at 1 and 3 h after intravenous administration of 185 MBq of 99m Tc-DTPA. GFR was also generated by a UV/P calculation derived from blood and urine samples. These mGFRs were compared with the eGFRs generated by 4 estimating equations: MDRD (Modified Diet in Renal Disease), CKD-EPI (Chronic Kidney Disease-Epidemiology Collaboration) (serum creatinine [SCr]), CKD-EPI (cystatin [CysC]), and CKD-EPI (CysC1SCr). eGFRs were compared with mGFRs by Pearson correlation, precision, bias, percentage bias, and accuracy (eGFRs varying by ,10% [p10], ,20% [p20] or ,30% [p30] from the corresponding mGFR). Results: All eGFRs showed poorer performance when the UV/P 99m Tc-DTPA mGFR was used as the reference than when the plasma 99m Tc-DTPA mGFR was used. When compared with the plasma 99m Tc-DTPA mGFR method, the performance of all eGFR equations was superior to most published reports. There was a moderately good positive correlation between eGFRs and mGFRs. When compared with plasma 99m Tc-DTPA mGFR, precision of eGFRs was in the range of 14-20 mL/min and showed a negligible bias. Compared with the plasma 99m Tc-DTPA mGFR, CKD-EPI (CysC1SCr) showed the best overall performance and accuracy, at 85.19% (p30), 75.93% (p20), and 42.59% (p10). Conclusion: Estimating equations for measuring eGFR performed better than in most published reports, attributable to use of the plasma 99m Tc-DTPA mGFR method as a reference. CKD-EPI (CysC1SCr) eGFR showed the best overall performance. However, more discriminating methods may be required when accurate GFR measurements are necessary. mGFR measurements using urine collections may introduce error compared with plasma-only methods.

to aid pregnant women with OUD in overcoming challenges faced within clinical care and research, subsequently improving the health of mothers and infants. Clinicians and researchers working with such vulnerable populations have an obligation to address and attend to the well-being of participants. Research staff, particularly those without a clinical background, need to be trained on the concerns addressed above, counseled on how and when to provide referrals and long-term support, and given adequate clinical support tsshemselves.