Non-diagnostic coronary artery calcification and stenosis: a correlation of coronary computed tomography angiography and invasive coronary angiography.

Background Heavy coronary artery calcification (CAC) impairs diagnostic accuracy of coronary computed tomography angiography (cCTA) and is considered to be a major limitation. Purpose To investigate the effect of non-evaluable CAC seen on cCTA on clinical decision-making by determining the degree of subsequent invasive testing and to assess the relationship between non-evaluable segments containing CAC and significant stenosis as seen in invasive coronary angiography (ICA). Material and Methods The study comprised of 356 patients who underwent cCTA and subsequent ICA within 2 months between 2005 and 2009. Clinical reports were reviewed to identify the indications for referral to ICA. In a subset of 68 patients where non-diagnostic CAC on cCTA and significant stenosis on ICA were present in the same segment, we correlated and analyzed the underlying stenosis severity of the lesion on ICA to the cCTA. Lesions with CAC were analyzed in a standardized fashion by application of reading rules. Results Non-diagnostic CAC on cCTA prompted ICA in 5.6% of patients. CAC occurred at the site of maximum stenosis in segments with stenosis <50% (95.9% [47/49]), 50-69% (82.4% [28/34]), 70-99% (64.5% [31/48]), and 100% (33.3% [1/3]). At the point of maximum calcium deposit, non-obstructive disease was present in 61.2%. Application of reading rules resulted in a 44% reduction in non-diagnostic cCTA reads. Conclusion Severe CAC may prompt further investigation with ICA. There is less CAC with increasing lesion severity at the point of maximum stenosis. Additional application of reading rules improved non-diagnostic cCTA reads.

Effect of the 2010 task force criteria on reclassification of cardiovascular magnetic resonance criteria for arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND: We sought to evaluate the effect of application of the revised 2010 Task Force Criteria (TFC) on the prevalence of major and minor Cardiovascular Magnetic Resonance (CMR) criteria for Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) versus application of the original 1994 TFC. We also assessed the utility of MRI to identify alternative diagnoses for patients referred for ARVC evaluation. METHODS: 968 consecutive patients referred to our institution for CMR with clinical suspicion of ARVC from 1995 to 2010, were evaluated for the presence of major and minor CMR criteria per the 1994 and 2010 ARVC TFC. CMR criteria included right ventricle (RV) dilatation, reduced RV ejection fraction, RV aneurysm, or regional RV wall motion abnormalities. When quantitative measures of RV size and function were not available, and in whom abnormal size or function was reported, a repeat quantitative analysis by 2 qualified CMR physicians in consensus. RESULTS: Of 968 patients, 220 (22.7%) fulfilled either a major or a minor 1994 TFC, and 25 (2.6%) fulfilled any of the 2010 TFC criterion. Among patients meeting any 1994 criteria, only 25 (11.4%) met at least one 2010 criterion. All patients who fulfilled a 2010 criteria also satisfied at least one 1994 criterion. Per the 2010 TFC, 21 (2.2%) patients met major criteria and 4 (0.4%) patients fulfilled at least one minor criterion. Eight patients meeting 1994 minor criteria were reclassified as satisfying 2010 major criteria, while 4 patients fulfilling 1994 major criteria were reclassified to only minor or no criteria under the 2010 TFC.Eighty-nine (9.2%) patients had alternative cardiac diagnoses, including 43 (4.4%) with clinically significant potential ARVC mimics. These included cardiac sarcoidosis, RV volume overload conditions, and other cardiomyopathies. CONCLUSIONS: Application of the 2010 TFC resulted in reduction of total patients meeting any diagnostic CMR criteria for ARVC from 22.7% to 2.6% versus the 1994 TFC. CMR identified alternative cardiac diagnoses in 9.2% of patients, and 4.4% of the diagnoses were potential mimics of ARVC.

Coronary computed tomography angiography at 140 kV versus 120 kV: assessment of image quality and radiation exposure in overweight and moderately obese patients.

BACKGROUND: Although a tube potential of 140 kV is available on most computed tomography (CT) scanners, its incremental diagnostic value versus 120 kV has been controversial. PURPOSE: To retrospectively evaluate the image quality and radiation exposure of cardiac computed tomography angiography (CCTA) performed at 140 kV in comparison to CCTA at 120 kV in overweight and moderately obese patients. MATERIAL AND METHODS: Eighty-eight patients who were referred for CCTA between January 2010 and May 2012 were included. Forty-four patients who were overweight or moderately obese (body mass index [BMI], 25-35 kg/m(2)) underwent CCTA with dual-source CT (DSCT) scanner at 140 kV. Forty-four match controls who underwent CCTA with DSCT at 120 kV were identified per BMI, average heart rate, scan indication, and scan acquisition mode. All scans were performed per routine protocols with direct physician supervision. Quantitative image metrics (CT attenuation, image noise, contrast-to-noise ratio [CNR], and signal-to-noise ratio [SNR] of left main [LM] and proximal right coronary artery [RCA]) were assessed. Effective radiation dose was compared between the two groups. RESULTS: Overall, all scans were diagnostic without any non-evaluable coronary segment per clinical report. 140 kV had a lower attenuation and image noise versus 120 kV (P<0.01). Both SNR and CNR of proximal coronary arteries were similar between 140 kV and 120 kV (SNR, LM P=0.93, RCA P=0.62; CNR, LM P=0.57, RCA P=0.77). 140 kV was associated with a 35.3% increase in effective radiation dose as compared with 120 kV (5.1 [3.6-8.2] vs. 3.3 [2.0-5.1] mSv, respectively; P<0.01). CONCLUSION: 140 kV CCTA resulted in similar image quality but a higher effective radiation dose in comparison to 120 kV CCTA. Therefore, in overweight and moderately obese patients, a tube potential of 120 kV may be sufficient for CCTA with diagnostic image quality.

Weekly dose reports: the effects of a continuous quality improvement initiative on coronary computed tomography angiography radiation doses at a tertiary medical center.

RATIONALE AND OBJECTIVES: Numerous protocols have been developed to reduce cardiac computed tomography angiography (cCTA) radiation dose while maintaining image quality. However, cCTA practice is highly dependent on physician and technologist experience and education. In this study, we sought to evaluate the incremental value of real-time feedback via weekly dose reports on a busy cCTA service. MATERIALS AND METHODS: This time series analysis consisted of 450 consecutive patients whom underwent physician-supervised cCTA for clinically indicated native coronary evaluation between April 2011 and January 2013, with 150 patients before the initiation of weekly dose report (preintervention period: April-September 2011) and 150 patients after the initiation (postintervention period: September 2011-February 2012). To assess whether overall dose reductions were maintained over time, results were compared to a late control group consisting of 150 consecutive cCTA exams, which were performed after the study (September 2012-January 2013). Patient characteristics and effective radiation were recorded and compared. RESULTS: Total radiation dose was significantly lower in the postintervention period (3.4 mSv [1.7-5.7] and in the late control group (3.3 mSv [2.0-5.3] versus the preintervention period (4.1 mSv [2.1-6.6] (P = .005). The proportion of high-dose outliers was also decreased in the postintervention period and late control period (exams <10 mSv were 88.0% preintervention vs. 97.3% postintervention vs. 95.3% late control; exams <15 mSv were 98.0% preintervention vs. 100.0% postintervention vs. 98.7% late control; exams <20.0 mSv were 98.7% preintervention vs. 100.0% postintervention vs. 100.0% late control). CONCLUSION: Weekly dose report feedback of site radiation doses to patients undergoing physician-supervised cCTA resulted in significant overall dose reduction and reduction of high-dose outliers. Overall dose reductions were maintained beyond the initial study period.

Resolution of an intracardiac mass with chemotherapy.

Right atrial intracardiac tumours are uncommonly seen during echocardiography. Our patient presented with primary mediastinal large B-cell lymphoma with intracardiac involvement. The tumour was seen by echocardiography and the extent of the tumour was defined by CT scan of the chest. Following chemotherapy directed to her specific tumour cell type, there was complete resolution of the intracardiac mass.

Assessment of image quality and radiation dose of prospectively ECG-triggered adaptive dual-source coronary computed tomography angiography (cCTA) with arrhythmia rejection algorithm in systole versus diastole: a retrospective cohort study.

In this study, we sought to evaluate the image quality and effective radiation dose of prospectively ECG-triggered adaptive systolic (PTA-systolic) dual-source CTA versus prospectively triggered adaptive diastolic (PTA-diastolic) dual-source CTA in patients of unselected heart rate and rhythm. This retrospective cohort study consisted of 41 PTA-systolic and 41 matched PTA-diastolic CTA patients whom underwent clinically indicated 128-slice dual source CTA between December 2010 to June 2012. Image quality and motion artifact score (both on a Likert scale 1-4 with 4 being the best), effective dose, and CTDIvol were compared. The effect of heart rate (HR) and heart rate variability [HRV] on image motion artifact score and CTDIvol was analyzed with Pearson's correlation coefficient. All 82 exams were considered diagnostic with 0 non-diagnostic segments. PTA-systolic CTA patients had a higher maximum HR, wider HRV, were less likely to be in sinus rhythm, and received less beta-blocker vs. PTA-diastolic CTA patients. No difference in effective dose was observed (PTA-systolic vs. PTA-diastolic CTA: 2.9 vs. 2.2 mSv, p = 0.26). Image quality score (3.3 vs. 3.5, p < 0.05) and motion artifact score (3.5 vs. 3.8, p < 0.05) were lower in PTA-systolic CTAs than in PTA-diastolic CTAs. For PTA-systolic CTAs, an increase in HR was not associated with a negative impact on motion artifact score nor CTDIvol. For PTA-diastolic CTA, an increase in HR was associated with increased motion artifacts and CTDIvol. HRV demonstrated no correlation with motion artifact and CTDIvol for both PTA-systolic and PTA-diastolic CTAs. In conclusion, both PTA-diastolic CTA and PTA-systolic CTA yielded diagnostic examinations at unselected heart rates and rhythms with similar effective radiation, but PTA-systolic CTA resulted in more consistent radiation exposure and image quality across a wide range of rates and rhythms.

Evolution of coronary computed tomography radiation dose reduction at a tertiary referral center.

PURPOSE: We aimed to assess the temporal change in radiation doses from coronary computed tomography angiography (CCTA) during a 6-year period. High CCTA radiation doses have been reduced by multiple technologies that, if used appropriately, can decrease exposures significantly. METHODS: A total of 1277 examinations performed from 2005 to 2010 were included. Univariate and multivariable regression analysis of patient- and scan-related variables was performed with estimated radiation dose as the main outcome measure. RESULTS: Median doses decreased by 74.8% (P<.001), from 13.1 millisieverts (mSv) (interquartile range 9.3-14.7) in period 1 to 3.3 mSv (1.8-6.7) in period 4. Factors associated with greatest dose reductions (P<.001) were all most frequently applied in period 4: axial-sequential acquisition (univariate: -8.0 mSv [-9.7 to -7.9]), high-pitch helical acquisition (univariate: -8.8 mSv [-9.3 to -7.9]), reduced tube voltage (100 vs 120 kV) (univariate: -6.4 mSv [-7.4 to -5.4]), and use of automatic exposure control (univariate: -5.3 mSv [-6.2 to -4.4]). CONCLUSIONS: CCTA radiation doses were reduced 74.8% through increasing use of dose-saving measures and evolving scanner technology.

Coronary computed tomography angiography during arrhythmia: Radiation dose reduction with prospectively ECG-triggered axial and retrospectively ECG-gated helical 128-slice dual-source CT.

BACKGROUND: Arrhythmia during coronary computed tomography angiography (coronary CTA) acquisition increases the risk of nondiagnostic segments and high radiation exposure. An advanced arrhythmia rejection algorithm for prospectively electrocardiogram (ECG)-triggered axial scans using dual-source CT (DSCT) examinations has recently been reported. OBJECTIVE: We compared image quality and effective dose at DSCT examinations using prospectively ECG-triggered axial scanning with advanced arrhythmia rejection software (PT-AAR) versus retrospectively ECG-gated helical scanning with tube-current modulation (RG-TCM) during arrhythmia. METHODS: This was a retrospective case-control study of 90 patients (43 PT-AAR, 47 RG-TCM) with arrhythmia (defined as heart rate variability [HRV] > 10 beats/min during data acquisition) referred for physician-supervised coronary CTA between April 2010 and September 2011. A subset of 22 cases matched for body mass index, HR, HRV, and other scan parameters was identified. Subjective image quality (4-point scale) and effective dose (dose length product method) were compared. RESULTS: PT-AAR was associated with lower effective dose than RG-TCM (4.1 vs 12.6 mSv entire cohort and 4.3 vs 9.1 mSv matched controls; both P < 0.01). Image quality scores were excellent in both groups (3.9 PT-AAR vs 3.6 RG-TCM) and nondiagnostic segment rates were low (0.1% vs 0.6%). Significantly higher image quality scores were found with PT-AAR in the entire cohort (P < 0.05), and in matched controls with high HRV > 28 beats/min (P < 0.05). CONCLUSIONS: In patients with variable heart rates, prospectively ECG-triggered axial DSCT with arrhythmia rejection algorithm is feasible and can decrease radiation exposure by ∼50% versus retrospectively ECG-gated helical DSCT, with preserved image quality.

Comparison of dual-source 64-slice adenosine stress CT perfusion with stress-gated SPECT-MPI for evaluation of left ventricular function and volumes.

BACKGROUND: Evaluation of left ventricular (LV) volumes and ejection fraction (LVEF) represent important components of pharmacologic stress imaging with either myocardial CT perfusion (CTP) or gated single-photon emission CT (SPECT) myocardial perfusion imaging (SPECT-MPI). OBJECTIVES: We compared measurements of left ventricular function and volumes obtained with CTP and SPECT-MPI. METHODS: Forty-seven patients (mean age, 62 ± 11 years; male, n = 39) underwent stress CTP and SPECT-MPI. LVEF (in %), end-systolic volume (ESV; in mL), and end-diastolic volume (EDV; in mL) derived from stress CTP images were compared with SPECT-MPI. RESULTS: Stress CTP was in good agreement with SPECT-MPI for quantification of LVEF (r = 0.91), EDV (r = 0.75), and ESV (r = 0.83; all P < 0.001). The mean LVEF measured by stress CTP (66% ± 17%) was similar to SPECT-MPI (64% ± 15%). Similar values were also derived for mean EDV (123 ± 30 mL vs 120 ± 34 mL) and ESV (44 ± 28 mL vs 51 ± 34 mL) for CTP and SPECT-MPI, respectively. Good agreement was also shown between both techniques for the assessment of regional wall motion with identical wall motion scores in 95.3% of the segments (κ = 0.79). CONCLUSIONS: LVEF and LV volume parameters as determined by dual-source 64-slice adenosine stress CTP show a high correlation with values obtained with stress-gated SPECT-MPI.

A comparison of reconstruction and viewing parameters on image quality and accuracy of stress myocardial CT perfusion.

BACKGROUND: Myocardial stress computed tomography perfusion (CTP) has similar diagnostic accuracy for detecting perfusion defects (PDs) versus single-photon emission computed tomography (SPECT). However, the optimal diagnostic viewing and image processing parameters for CTP are unknown. OBJECTIVE: We sought to compare the diagnostic accuracy of different image processing techniques, cardiac phases, slice thicknesses, and viewing parameters for detection of PDs. METHODS: A stress and rest dual-source CTP protocol was performed with adenosine. Twelve subjects with severe stenosis proven by quantitative coronary angiography (QCA), with corresponding territorial defects at SPECT, were selected as well as 7 controls (subjects with similar clinical suspicion but negative QCA and SPECT). Short-axis stress images were processed with 3 techniques: minimum intensity projection (MinIP), maximum intensity projection, and average intensity multiplanar reconstruction (MPR), 3 thicknesses (1, 3, 8 mm), and 2 phases (systolic, mid-diastolic). The resulting images (n = 1026) were randomized and interpreted by independent readers. RESULTS: Diastolic reconstructions (8-mm MPR) showed the highest sensitivity (81%) to detect true PDs. The highest accuracy was achieved with the 8-mm (61%) and 1-mm (61%) MPR diastolic images. The most sensitive and accurate systolic reconstructions were 3-mm MinIP images. These findings related to viewing in relatively narrow window width and window level settings. CONCLUSION: Viewing parameters for optimal accuracy in detection of perfusion defects on CTP differ for systolic and diastolic images.