Prognostic utility of sestamibi lung uptake does not require adjustment for stress-related variables: A retrospective cohort study

BACKGROUND: Increased (99m)Tc-sestamibi stress lung-to-heart ratio (sLHR) has been shown to predict cardiac outcomes similar to pulmonary uptake of thallium. Peak heart rate and use of pharmacologic stress affect the interpretation of lung thallium uptake. The current study was performed to determine whether (99m)Tc-sestamibi sLHR measurements are affected by stress-related variables, and whether this in turn affects prognostic utility. METHODS: sLHR was determined in 718 patients undergoing (99m)Tc-sestamibi SPECT stress imaging. sLHR was assessed in relation to demographics, hemodynamic variables and outcomes (mean follow up 5.6 ± 1.1 years). RESULTS: Mean sLHR was slightly greater in males than in females (P < 0.01) and also showed a weak negative correlation with age (P < 0.01) and systolic blood pressure (P < 0.01), but was unrelated to stress method or heart rate at the time of injection. In patients undergoing treadmill exercise, sLHR was also positively correlated with peak workload (P < 0.05) but inversely with double product (P < 0.05). The combined explanatory effect of sex, age and hemodynamic variables on sLHR was less than 10%. The risk of acute myocardial infarction (AMI) or death increased by a factor of 1.7–1.8 for each SD increase in unadjusted sLHR, and was unaffected by adjustment for sex, age and hemodynamic variables (hazard ratios 1.6–1.7). The area under the ROC curve for the unadjusted sLHR was 0.65 (95% CI 0.59–0.71, P < 0.0001) and was unchanged for the adjusted sLHR (0.65, 95% CI 0.61–0.72, P < 0.0001). CONCLUSION: Stress-related variables have only a weak effect on measured sLHR. Unadjusted and adjusted sLHR provide equivalent prognostic information for prediction of AMI or death

Gadobutrol-enhanced cardiac magnetic resonance imaging for detection of coronary artery disease

BACKGROUND: Gadolinium-based contrast agents were not approved in the United States for detecting coronary artery disease (CAD) prior to the current studies. OBJECTIVES: The purpose of this study was to determine the sensitivity and specificity of gadobutrol for detection of CAD by assessing myocardial perfusion and late gadolinium enhancement (LGE) imaging. METHODS: Two international, single-vendor, phase 3 clinical trials of near identical design, "GadaCAD1" and "GadaCAD2," were performed. Cardiovascular magnetic resonance (CMR) included gadobutrol-enhanced first-pass vasodilator stress and rest perfusion followed by LGE imaging. CAD was defined by quantitative coronary angiography (QCA) but computed tomography coronary angiography could exclude significant CAD. RESULTS: Because the design and results for GadaCAD1 (n = 376) and GadaCAD2 (n = 388) were very similar, results were summarized as a fixed-effect meta-analysis (n = 764). The prevalence of CAD was 27.8% defined by a ≥70% QCA stenosis. For detection of a ≥70% QCA stenosis, the sensitivity of CMR was 78.9%, specificity was 86.8%, and area under the curve was 0.871. The sensitivity and specificity for multivessel CAD was 87.4% and 73.0%. For detection of a 50% QCA stenosis, sensitivity was 64.6% and specificity was 86.6%. The optimal threshold for detecting CAD was a ≥67% QCA stenosis in GadaCAD1 and ≥63% QCA stenosis in GadaCAD2. CONCLUSIONS: Vasodilator stress and rest myocardial perfusion CMR and LGE imaging had high diagnostic accuracy for CAD in 2 phase 3 clinical trials. These findings supported the U.S. Food and Drug Administration approval of gadobutrol-enhanced CMR (0.1 mmol/kg) to assess myocardial perfusion and LGE in adult patients with known or suspected CAD

Application of Staging Systems for Differentiated Thyroid Carcinoma in an Endemic Goiter Region With Iodine Substitution

OBJECTIVE: To evaluate and compare staging systems for differentiated thyroid carcinoma and predicted outcome in an endemic goiter region with iodine substitution and to examine the risk profile of differentiated thyroid carcinoma and compare it against nongoiter regions. SUMMARY BACKGROUND DATA: Differentiated (papillary or follicular) thyroid carcinoma has a favorable prognostic outcome. In numerous studies prognostic factors have been identified and staging systems created, particularly in Anglo-American centers (nonendemic goiter regions), to evaluate individual prognostic outcome. METHODS: In a retrospective study, the authors assessed 440 patients with differentiated thyroid carcinoma (papillary, n = 293; follicular, n = 147) and a long-term follow-up of median 10.6 years to determine the predictive accuracy of nine staging systems applicable to the study population; the systems were compared by calculating the proportion of variation explained. RESULTS: With regard to cause-specific mortality, the difference between the respective stages and/or risk groups was highly significant for every staging system. By means of calculating the proportion of variation explained, MACIS scoring supplied the most reliable prognostic information for differentiated thyroid carcinoma (relative importance 16.93%). EORTC and UICC/AJCC systems had a relative importance of 16.34% and 13.96%, respectively, also a high level of accuracy; this implies that they are superior to the other six staging systems. If we separate papillary and follicular carcinoma, for the former the MACIS score with a relative importance of 15.05% is clearly superior to the other staging systems, whereas for the latter the EORTC score and the UICC/AJCC staging system, with relative importance of 17.04% and 16.58%, respectively, yield the best prognostic information. CONCLUSIONS: By applying staging systems in an endemic goiter region with iodine substitution, the best prognostic information for papillary thyroid carcinoma has been achieved with the MACIS score, while for follicular thyroid carcinoma the EORTC score and the UICC/AJCC system have the best prognostic accuracy. Because of the individual factors, which are easy to obtain and generally available (age, T, N, M classification), the uncomplicated handling, and the widespread use and the good predictive accuracy, the UICC/AJCC classification is the staging system of choice for comparing published results

Dosimetry and First Clinical Evaluation of the New 18F-Radiolabeled Bombesin Analogue BAY 864367 in Patients with Prostate Cancer

UNLABELLED The aim of this first-in-man study was to demonstrate the feasibility, safety, and tolerability, as well as provide dosimetric data and evaluate the imaging properties, of the bombesin analogue BAY 864367 for PET/CT in a small group of patients with primary and recurrent prostate cancer (PCa). METHODS Ten patients with biopsy-proven PCa (5 with primary PCa and 5 with prostate-specific antigen recurrence after radical prostatectomy) were prospectively selected for this exploratory clinical trial with BAY 864367, a new (18)F-labeled bombesin analogue. PET scans were assessed at 6 time points, up to 110 min after intravenous administration of 302 ± 11 MBq of BAY 864367. Imaging results were compared with (18)F-fluorocholine PET/CT scans. Dosimetry was calculated using the OLINDA/EXM software. RESULTS Three of 5 patients with primary disease showed positive tumor delineation in the prostate, and 2 of 5 patients with biochemical relapse showed a lesion suggestive of recurrence on the BAY 864367 scan. Tumor-to-background ratio averaged 12.9 ± 7.0. The ratio of malignant prostate tissue to normal prostate tissue was 4.4 ± 0.6 in 3 patients with tracer uptake in the primary PCa. Mean effective dose was 4.3 ± 0.3 mSv/patient (range, 3.7-4.9 mSv). CONCLUSION BAY 864367, a novel (18)F-labeled bombesin tracer, was successfully investigated in a first-in-man clinical trial of PCa and showed favorable dosimetric values. Additionally, the application was safe and well tolerated. The tracer delineated tumors in a subset of patients, demonstrating the potential of gastrin-releasing-peptide receptor imaging