Diagnostic accuracy of sub-mSv prospective ECG-triggering cardiac CT in young infant with complex congenital heart disease

Abstract

To explore the clinical value and evaluate the diagnostic accuracy of sub-mSv low-dose prospective ECG-triggering cardiac CT (CCT) in young infants with complex congenital heart disease (CHD). A total of 102 consecutive infant patients (53 boys and 49 girls with mean age of 2.9 ± 2.4 m and weight less than 5 kg) with complex CHD were prospectively enrolled. Scans were performed on a 64-slice high definition CT scanner with low dose prospective ECG-triggering mode and reconstructed with 80 % adaptive statistical iterative reconstruction algorithm. All studies were performed during free breathing with sedation. The subjective image quality was evaluated by 5-point grading scale and interobserver variability was calculated. The objective image noise (standard deviation, SD) and contrast to noise ratio (CNR) was calculated. The effective radiation dose from the prospective ECG-triggering mode was recorded and compared with the virtual conventional retrospective ECG-gating mode. The detection rate for the origin of coronary artery was calculated. All patients also underwent echocardiography before CCT examination. 81 patients had surgery and their preoperative CCT and echocardiography findings were compared with the surgical results and sensitivity, specificity, positive and negative predictive values and accuracy were calculated for separate cardiovascular anomalies. Heart rates were 70-161 beats per minute (bpm) with mean value of 129.19 ± 14.52 bpm. The effective dose of 0.53 ± 0.15 mSv in the prospective ECG-triggering cardiac CT was lower than the calculated value in a conventional retrospective ECG-gating mode (2.00 ± 0.35 mSv) (p < 0.001). The mean CNR and SD were 28.19 ± 13.00 and 15.75 ± 3.61HU, respectively. The image quality scores were 4.31 ± 0.36 and 4.29 ± 0.41 from reviewer 1 and 2 respectively with an excellent agreement between them (Kappa = 0.85). The detection rate for the origins of the left and right coronary arteries was 96 and 90 %, respectively. The detection rates of the origins of left coronary artery and right coronary artery in all cases were 96 % (78/81) and 90 % (73/81), respectively. Twenty cases of conotruncal anomalies and ALCAPA were validated surgically and the accuracy of cardiac CT diagnosis was 95 % (19/20). The overall deformity based sensitivity, specificity, positive predictive value and negative predictive value were 94.0.1, 99.9, 98.6, 99.5 % respectively, by CCT, and 88.2, 99.9, 97.8, 99.0 %, respectively, by echocardiography. Prospective ECG-triggering CCT with sub-mSv effective dose provides excellent imaging quality and high diagnostic accuracy for young infants with complex CHD.

Evaluation of the CT imaging findings in patients newly diagnosed with chronic thromboembolic pulmonary hypertension

“…Third, although retrospectively ECG-triggered MDCTA more clearly depicts ventricular morphology than helical CT scanning mode, retrospective ECG-gating is currently not recommended as a routine MDCTA protocol because of its higher radiation dose compared with helical scanning mode. Recent studies showed that the use of prospective ECG-gating significantly reduces the radiation exposure to patients undergoing MDCTA and yields diagnostic image quality in the assessment of coronary arteries [ 42 – 45 ], coronary artery bypasses [ 46 ], and congenital heart disease [ 47 ] with lower radiation dose. Future studies are warranted that evaluate the diagnostic accuracy of low-dose prospectively ECG-triggered MDCTA in patients with CTEPH.…”

A prospective evaluation of contrast and radiation dose and image quality in cardiac CT in children with complex congenital heart disease using low-concentration iodinated contrast agent and low tube voltage and current

“…The scan parameters for prospective scanning were the same as that of our previous study. 8 The detailed parameters were as follows: prospectively ECGtriggered step-and-shoot axial scanning and a collimation of 64 3 0.625 mm with a scan field of view of 25 cm and gantry rotation time of 0.35 s. The data acquisition window was 380 ms with padding technique. The centre of the data acquisition window was set at 35-45% of the R-R interval when heart rate was over 75 bpm and at 65-85% of the R-R interval when heart rate was lower than 75 bpm.…”

Cardiovascular CT in Cyanotic Congenital Heart Disease

“…Since then, innovations such as prospective ECG gating, ECG-controlled tube current modulation, high-pitch helical scanning, lower tube potentials, wider detector coverage, and iterative reconstruction techniques have dramatically lowered radiation exposure [33,34]. Today, sub-milliSievert scans are achievable in many children [35]. However, effective doses still vary widely, and recently published pediatric cardiac-specific dose-length product conversion or "k-"factors suggest that k-factors, and therefore effective cardiac radiation doses, in children are considerably higher than previously believed [32,36].…”

“…With dual-source scan technology and wide detector coverage, studies can be obtained in a single heartbeat without requiring a breath hold for most indications. General anesthesia and paralysis are not necessary in most patients [35,36]. While cardiac MRI in critically ill and often unstable patients poses significant risks because of study length, need for sedation, the need to change MRI-incompatible ventilators and lines, and difficulties with closely monitoring patients inside the scanner, cardiac CT mitigates these risks.…”