SPECT/CT significantly improved the specificity and positive predictive value of bone scintigraphy in cancer patients. In breast cancer patients, we found a slight increase in sensitivity. SPECT/CT had a significant effect on clinical management because of correct downstaging and upstaging, better definition of the extent of metastases, and a reduction in further diagnostic procedures.

After renal transplantation monitoring and detection of slight-to-moderate changes in GFR is a prerequisite for an optimal patient management. Recently, several equations to estimate GFR were developed and verified in the MDRD study cohort. However, little is known about the application of the MDRD formulas in the setting of renal transplantation. We prospectively conducted a study of the GFR estimates of the Cockcroft and Gault (C&G), MDRD6-, MDRD7 and the abbreviated MDRD (aMDRD) with the true GFR as measured by99m Tc-DTPA clearance in 95 consecutive patients 6.5, 5.3-7.7 years (mean, 95% CI) after renal transplantation.On average the DTPA clearance was 37.4, 34.4-40.4 mL/min/1.73m 2 , which differed significantly from estimates of GFR by C&G (52.6, 48.3-56.9 mL/min/1.73m 2 ), MDRD7 (44.8, 40.7-49.0 mL/min/1.73m 2 ), MDRD6 (43.8, 39.9-47.7 mL/min/1.73m 2 ) and aMDRD (46.6, 42.4-50.9 mL/min/1.73m 2 ). Bias was lowest for MDRD6 (6.4 mL/min/1.73m 2 ) and highest for C&G (15.2 mL/min/1.73m 2 ). Precision was similar for MDRD7 and aMDRD (10.6 and 11.1 mL/min/1.73m2 ) but significantly better for MDRD6 (8.6 mL/min/1.73m 2 ; p < 0.035). Accuracy within 50% of real GFR was 55.8% for C&G, 83.2% for aMDRD, 87.4% for MDRD7 and 90.5% for MDRD6. MDRD equations perform significantly better than the commonly used C&G formula. Moreover, the MDRD6 equation provides the best diagnostic performance, and should therefore be preferred in renal transplant recipients.

Our data suggest a significant improvement of GFR estimation in liver cirrhotics by means of the Cys C-based Hoek and Larsson formulae. However, all estimates remain a crude approximation of true GFR and thus cannot replace gold standard methods.

BTP serum levels may serve as a surrogate marker for residual renal function since HD and HDF do not exert clinical relevant alterations on them. Furthermore, BTP serum concentrations appear strongly associated to RD.

Cystatin C (Cys C) has been shown to be an alternative marker of renal function. However, estimation of the glomerular filtration rate (GFR) based on Cys C has received little attention. Recently, several Cys C-based equations were developed in different patient cohorts. To date, the benefit of a Cys C-based GFR calculation in patients after renal transplantation (RTx) remains to be elucidated. We compared the diagnostic accuracy of three Cys C-based formulae (Larsson, Hoek, Filler which used an immunonephelometric method) with the results of the Modification of Diet in Renal Disease (MDRD) formula. GFR was measured by means of technetium-diethylenetriamine pentaacetic acid ((99m)Tc-DTPA) clearance in 108 consecutive patients after RTx. Correlation coefficients of all calculated GFR estimates with the true GFR were high but did not differ significantly from one another (0.83-0.87). The MDRD and Filler equations overestimated GFR significantly, whereas the Larsson equation significantly underestimated GFR. Bias of the Hoek formula was negligible. Precision of the Hoek (8.9 ml/min/1.73 m(2)) and Larsson equations (9.6 ml/min/1.73 m(2)) were significantly better than MDRD equations (11.4 ml/min/1.73 m(2); P< or =0.035 each). Accuracy within 30% of real GFR was 67.0 and 65.1% for the MDRD and Filler formulae, and 77.1% for the Larsson and Hoek formulae, respectively. Accuracy within 50% of true GFR for the Hoek formula (97.2%) was better than for the MDRD equations (85.3%). Cys C-based formulae may provide a better diagnostic performance than creatinine-based equations in GFR calculation after RTx.