Prospective comparison of computed tomography, diffusion-weighted magnetic resonance imaging and [11C]choline positron emission tomography/computed tomography for preoperative lymph node staging in prostate cancer patients.

PURPOSE: The aim of this study was to prospectively compare diffusion-weighted magnetic resonance imaging (DWI) and [(11)C]choline positron emission tomography/computed tomography (PET/CT) with computed tomography (CT) for preoperative lymph node (LN) staging in prostate cancer (PCa) patients. METHODS: Between June 2010 and May 2012, CT, DWI and [(11)C]choline PET/CT were performed preoperatively in 33 intermediate- and high-risk PCa patients undergoing radical prostatectomy (RP) and extended pelvic lymph node dissection (ePLND) including obturator fossa and internal, external and common iliac fields. Patient- and field-based performance characteristics for all three imaging techniques based on histopathological results are reported. Imaging techniques were compared by means of the area under the curve (AUC). RESULTS: LN metastases were detected in 92 of 1,012 (9%) LNs from 14 of 33 (42%) patients. On patient-based analysis, sensitivity, specificity and accuracy for CT were 57, 68 and 64%, respectively, for DWI were 57, 79 and 70%, respectively, and for [(11)C]choline PET/CT were 57, 90 and 76%, respectively. On field-based analysis, these numbers for CT were 47, 94 and 88%, respectively, for DWI were 56, 97 and 92%, respectively, and for [(11)C]choline PET/CT were 62, 96 and 92%, respectively. Neither DWI nor [(11)C]choline PET/CT performed significantly better than CT on pairwise comparison of patient- and field-based results. CONCLUSION: All three imaging techniques exhibit a rather low sensitivity with less than two thirds of LN metastases being detected on patient- and field-based analysis. Overall diagnostic efficacy did not differ significantly between imaging techniques, whereas distinct performance characteristics, esp. patient-based specificity, were best for [(11)C]choline PET/CT followed by DWI and CT.

Myocardium: dynamic versus single-shot CT perfusion imaging.

PURPOSE: To determine the diagnostic accuracy of dynamic computed tomographic (CT) perfusion imaging of the myocardium for the detection of hemodynamically relevant coronary artery stenosis compared with the accuracy of coronary angiography and fractional flow reserve (FFR) measurement. MATERIALS AND METHODS: This study was approved by the institutional review board and the Federal Radiation Safety Council (Bundesamt für Strahlenschutz). All patients provided written informed consent. Thirty-two consecutive patients in adenosine stress conditions underwent dynamic CT perfusion imaging (14 consecutive data sets) performed by using a 256-section scanner with an 8-cm detector and without table movement. Time to peak, area under the curve, upslope, and peak enhancement were determined after calculation of time-attenuation curves. In addition, myocardial blood flow (MBF) was determined quantitatively. Results were compared with those of coronary angiography and FFR measurement by using a receiver operating characteristic (ROC) analysis. In addition, threshold values based on the Youden index and sensitivity and specificity were calculated. RESULTS: Area under the ROC curve, sensitivity, and specificity, respectively, were 0.67, 41.4% (95% confidence interval [CI]: 23.5%, 61.1%), and 86.6% (95% CI: 76.0%, 93.7%) for time to peak; 0.74, 58.6% (95% CI: 38.9%, 76.5%), and 83.6% (95% CI: 72.5%, 91.5%) for area under the curve; 0.87, 82.8% (95% CI: 64.2%, 94.1%), and 88.1% (95% CI: 77.8%, 94.7%) for upslope; 0.83, 82.8% (95% CI: 64.2%, 94.1%), and 89.6% (95% CI: 79.6%, 95.7%) for peak enhancement; and 0.86, 75.9% (95% CI: 56.5%, 89.7%), and 100% (95% CI: 94.6%, 100%) for MBF. The thresholds determined by using the Youden index were 148.5 HU · sec for area under the curve, 12 seconds for time to peak, 2.5 HU/sec for upslope, 34 HU for peak enhancement, and 1.64 mL/g/min for MBF. CONCLUSION: The semiquantitative parameters upslope and peak enhancement and the quantitative parameter MBF showed similar high diagnostic accuracy. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13121441/-/DC1.

Prognostic implications of coronary CT angiography-derived quantitative markers for the prediction of major adverse cardiac events.

OBJECTIVE: To evaluate quantitative markers derived from coronary CT angiography (coronary CTA) for the prediction of major adverse cardiac events (MACE). MATERIALS AND METHODS: Pooled data from two centers in the US and Europe were retrospectively analyzed. Forty-six patients (65.5 ± 8.1 years, 62% male) with suspected coronary artery disease (CAD) who had undergone dual-source CCTA and had experienced MACE within 12 months were included and compared to a Framingham risk score matched cohort (n = 46) without MACE. Various quantitative markers derived from coronary CTA were compared between both groups: Total plaque volume (TPV), calcified and non-calcified plaque volumes (CPV and NCPV), plaque burden (%), remodeling index, lesion length, presence of Napkin-ring sign, segment involvement score (SIS), and segment stenosis score (SSS). Discriminatory power of these markers for predicting MACE was assessed. RESULTS: Patients with MACE had significantly more obstructive CAD with higher plaque burden, SSS, and SIS (all p < 0.05) compared to controls. MACE-related lesions showed higher median TPV (122.6 mm3 vs. 76.3 mm3), NCPV (67.3 mm3 vs. 56.1 mm3), plaque burden (66.3% vs. 44.9%), greater lesion length (23.1 mm vs. 19.2 mm), and higher prevalence of Napkin-ring sign (63% vs. 32%) (all p < 0.05). On multivariable analysis, odds ratios (OR) for MACE on a per-patient level were 1.07 for plaque burden (p = 0.0002) and 1.13 for SSS (p = 0.049). On a per-lesion basis OR for lesion length was 1.05 (p = 0.042), 1.03 for plaque burden (p = 0.018), 1.28 for remodeling index (p = 0.026), and 1.68 for the Napkin-ring sign (p = 0.031). At receiver operating characteristics analysis a combination of markers (Framingham risk score + Napkin-ring sign + lesion length + remodeling index) showed the highest predictive value for MACE (AUC 0.92, p = 0.013). CONCLUSION: Coronary CTA-derived markers portend predictive value for MACE on a per-patient (plaque burden and SSS) and per-lesion level (lesion length, plaque burden, remodeling index, and Napkin-ring sign). A combination of markers added to the Framingham risk score has the highest predictive power.

Dual-source RF transmission in cardiac SSFP imaging at 3 T: systematic spatial evaluation of image quality improvement compared to conventional RF transmission.

The purpose of this investigation was to systematically evaluate the spatial distribution of image quality improvement with dual-source radiofrequency (RF) transmission in cardiac steady-state free precession sequences at 3.0 T. Imaging with and without dual-source RF transmission was performed in 30 patients. Contrast-to-noise ratio for the left ventricular myocardium was significantly higher using dual-source RF transmission, but improvement was not uniformly distributed. The posterior myocardium showed significantly less contrast-to-noise ratio gain than all other cardiac regions. Signal-to-noise ratio increase was higher in the right than in the left ventricle. Subjective image quality was significantly enhanced by parallel RF transmission.

Dynamic CT perfusion imaging of the myocardium using a wide-detector scanner: a semiquantitative analysis in an animal model.

BACKGROUND: Functional assessment of myocardial perfusion in computed tomography (CT) is a challenge. OBJECTIVE: To evaluate CT dynamic myocardial perfusion imaging (MPI) using a wide-detector scanner. METHODS: Time to peak (TTP), peak enhancement (PE), upslope (US), and the area under the curve (AUC) were calculated in 12 pigs (256-slice multidetector CT scanner). RESULTS: The entire myocardium was covered by the scan volume. TTP was increased, and PE, US, and AUC were decreased in poststenotic myocardium. CONCLUSION: CT MPI with complete coverage of the myocardium is feasible, providing evaluation of the physiological significance of coronary artery stenosis.

256-slice CT angiographic evaluation of coronary artery bypass grafts: effect of heart rate, heart rate variability and Z-axis location on image quality.

PURPOSE: The objective of this study is to assess the effect of heart rate, heart rate variability and z-axis location on coronary artery bypass graft (CABG) image quality using a 256-slice computed tomography (CT) scanner. METHODS: A total of 78 patients with 254 CABG (762 graft segments) were recruited to undergo CABG assessment with 256-slice CT and prospective ECG-gating. Two observers rated graft segments for image quality on a 5-point scale. Quantitative measurements were also made. Logistic and cumulative link mixed models were used to assess the predictors of graft image quality. RESULTS: Graft image quality was judged as diagnostic (scores 5 (excellent), 4 (good) and 3 (moderate)) in 96.6% of the 762 segments. Interobserver agreement was excellent (kappa ≥0.90). Graft image quality was not affected by heart rate level. However, high heart rate variability was associated with an important and significant image quality deterioration (odds ratio 4.31; p  =  0.036). Distal graft segments had significantly lower image quality scores than proximal segments (p ≤ 0.02). Significantly higher noise was noted at the origin of the mammary grafts (p  =  0.001), owing to streak artifacts from the shoulders. CONCLUSION: CABG imaging with 270-msec rotation 256-slice CT and prospective ECG-gating showed an adequate image quality in 96.6% of graft segments, and an excellent interobserver agreement. Graft image quality was not influenced by heart rate level. Image quality scores were however significantly decreased in patients with high heart rate variability, as well as in distal graft segments, which are closer to the heart.