A review of adherence to the guidelines for coronary CT angiography quantitative stenosis grading thresholds in published research.

BACKGROUND: The degree of coronary stenosis of potential hemodynamic significance is central to the interpretation of coronary computed tomography angiography (CCTA), but has been variably defined in the literature. Societal guidelines have attempted to address this issue via recommended thresholds. OBJECTIVES: We surveyed the various thresholds for defining significant coronary stenosis reported in research published since the introduction of the Society for Cardiovascular Computed Tomography guidelines regarding the interpretation and reporting of CCTA. METHODS: We systematically reviewed the results of bibliographic searches of all original research articles on CCTA, focusing on studies reporting > 25 subjects, to assess the definitions of severity of coronary lesions as found on CCTA. To enable comparisons, we stratified the methods of reporting lesion severity into ≥ 50%, 50% to 69%, and "others" (including infrequent reporting methods). RESULTS: Fifty-nine11 published studies were identified and met inclusion criteria. Eighteen studies reported the severity of coronary stenosis using a definition of 50% to 69% as moderate stenosis; 35 studies defined ≥ 50% coronary stenosis as "stenosis," "significant stenosis," or "obstructive lesion" without distinguishing a threshold for moderate versus severe stenosis. Six studies utilized other thresholds, such as 20% to 75%, 40% to 69%, 40% to 70%, 40% to 79%, and 50% to 75% to define moderate coronary stenosis. CONCLUSIONS: Fifty-three of 59 studies were graded in accordance with the recommended threshold of ≥ 50% defining potentially significant stenosis, with 18 studies reporting precisely in accordance with the guidelines-recommended thresholds of ≥ 50% narrowing as defining moderate stenosis and ≥ 70% narrowing as defining severe stenosis. Six studies were reported using alternative thresholds for significant stenosis. However, a majority of research studies published since 2009 do not follow the societal guidelines for stenosis grading, since these studies do not clearly describe the degree of coronary stenosis.

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.