CT Perfusion Versus Coronary CT Angiography in Patients With Suspected In-Stent Restenosis or CAD Progression.

OBJECTIVES: The goal of this study was to assess the diagnostic performance of coronary computed tomography angiography (CTA) alone, adenosine-stress myocardial perfusion assessed by computed tomography (CTP) alone, and coronary CTA + CTP by using a 16-cm Z-axis coverage scanner versus invasive coronary angiography (ICA) and fractional flow reserve (FFR) as the clinical standard. BACKGROUND: Diagnostic performance of coronary CTA for in-stent restenosis detection is still challenging. Recently, CTP showed additional diagnostic power over coronary CTA in patients with suspected coronary artery disease. However, few data are available on CTP performance in patients with previous stent implantation. METHODS: Consecutive stable patients with previous coronary stenting referred for ICA were enrolled. All patients underwent stress myocardial CTP and rest CTP + coronary CTA. Invasive FFR was performed during ICA when clinically indicated. The diagnostic rate and diagnostic accuracy of coronary CTA, CTP, and coronary CTA + CTP were evaluated in stent-, territory-, and patient-based analyses. RESULTS: In the 150 enrolled patients (132 men; mean age 65.1 ± 9.1 years), the CTP diagnostic rate was significantly higher than that of coronary CTA in all analyses (territory based [96.7% vs. 91.1%; p < 0.0001] and patient based [96% vs. 68%; p < 0.0001]). When ICA was used as gold standard, CTP diagnostic accuracy was significantly higher than that of coronary CTA in all analyses (territory based [92.1% vs. 85.5%, p < 0.03] and patient based [86.7% vs. 76.7%, p < 0.03]). The concordant coronary CTA + CTP assessment exhibited the highest diagnostic accuracy values versus ICA (95.8% in the territory-based analysis). The diagnostic accuracy of CTP was significantly higher than that of coronary CTA (75% vs. 30.5%; p < 0.001). The radiation exposure of coronary CTA + CTP was 4.15 ± 1.5 mSv. CONCLUSIONS: In patients with coronary stents, CTP significantly improved the diagnostic rate and accuracy of coronary CTA alone compared with both ICA and invasive FFR as gold standard.

Low-Dose Coronary CT Angiography in Patients with Atrial Fibrillation: Comparison of Image Quality and Radiation Exposure with Two Different Approaches.

RATIONALE AND OBJECTIVES: To evaluate image quality, coronary interpretability and radiation exposure of coronary CT angiography (CCTA) performed in patients with atrial fibrillation (AF) with the latest scanner generation, comparing two different technical approaches. A new scanner that combines a 0.23 mm spatial resolution, a new generation of iterative reconstruction, fast gantry rotation time and the intracycle motion-correction algorithm to improve the temporal resolution was recently introduced in the clinical field. MATERIALS AND METHODS: We enrolled 105 consecutive patients with chronic AF who performed CCTA with a whole-heart coverage high-definition CT scanner (16-cm z-axis coverage with 256 detector rows, 0.28 s gantry rotation time). Five of them were excluded for impaired renal function. Patients were randomized between a double acquisition protocol (50 patients, group 1) or a single acquisition protocol (50 patients, group 2). The image quality, coronary segment interpretability and effective dose (ED) of CCTA were assessed. RESULTS: The mean HR during the scan was 85.6±21 bpm in group 1 vs. 83.7±23 bpm in Group 2, respectively (p < ns). In group 2, overall image quality was high and comparable with that of group 1 (Likert scale =3.2 ± 1.4 vs. 3.3 ± 1.2, p = ns, in group 1 and 2, respectively). Coronary interpretability was high and similar between the two groups (97.5% and 97.1% in group 1 and 2, p = ns, respectively). Mean ED was significantly higher in group 1 than in group 2 (5.3 ± 1.8 mSv vs. 2.7 ± 0.7 mSv, p < 0.001). CONCLUSION: The novel whole-heart coverage CT scanner allows to perform CCTA with a single-acquisition protocol with high image quality and low radiation exposure in AF patients.

Diagnostic accuracy of coronary CT angiography performed in 100 consecutive patients with coronary stents using a whole-organ high-definition CT scanner.

AIMS: To evaluate image quality, interpretability, diagnostic accuracy and radiation exposure of coronary CT angiography (CCTA) performed with a new scanner equipped with 0.23-mm spatial resolution, new generation iterative reconstruction, 0.28-second gantry rotation time and intra-cycle motion-correction algorithm in consecutive patients with coronary stents, including those with high heart rate (HR) and atrial fibrillation (AF). MATERIALS AND METHODS: We enrolled 100 consecutive patients (85 males, mean age 65 ±â€¯10 years) with previous coronary stent implantation scheduled for clinically indicated non-emergent invasive coronary angiography (ICA). Image quality, coronary interpretability and diagnostic accuracy vs. ICA were evaluated and the effective dose (ED) was recorded. RESULTS: Mean HR during the scan was 67 ±â€¯13 bpm. Twenty-six patients had >65 bpm HR during scanning and 13 patients had AF. Overall, image quality was high (Likert = 3.2 ±â€¯0.9). Stent interpretability was 95.8% (184/192 stents). Among 192 stented segments, CCTA correctly identified 22 out of 24 with >50% in-stent restenosis (ISR) (sensitivity 92%). In a stent-based analysis, specificity, positive and negative predictive values and diagnostic accuracy for ISR detection were 91%, 99%, 60% and 91%, respectively. In a patient-based analysis, CCTA diagnostic accuracy was 85%. Overall, mean ED of CCTA was 2.4 ±â€¯1.2 mSv. CONCLUSIONS: A whole-organ CT scanner was able to evaluate coronary stents with good diagnostic performance and low radiation exposure, also in presence of unfavorable HR and heart rhythm. TRANSLATIONAL ASPECT: The present study is the first to evaluate the CCTA capability of detecting in-stent restenosis in consecutive patients, including those with high HR and AF, using a recent scanner generation that combines improved spatial and temporal resolution with wide coverage. Using the whole-organ high-definition CT scanner we obtained high quality images of coronary stents with good interpretability and diagnostic accuracy combined with low radiation exposure, even in patients with unfavorable HR or heart rhythm for CCTA evaluation.

Myocardial deformation in iron overload cardiomyopathy: speckle tracking imaging in a beta-thalassemia major population.

Traditional echocardiography is unable to detect neither the early stages of iron overload cardiomyopathy nor myocardial iron deposition. The aim of the study is to determine myocardial systolic strain indices in thalassemia major (TM), and assess their relationship with T2*, a cardiac magnetic resonance index of the severity of cardiac iron overload. 55 TM cases with recent cardiac magnetic resonance (CMR-T2*) underwent speckle tracking analysis to assess regional myocardial strains and rotation. The results were compared with a normal control group (n = 20), and were subsequently analyzed on the basis of the CMR-T2* values. Two TM groups were studied: TM with significant cardiac iron overload ("low" T2*, ≤20 ms; n = 21), and TM with normal T2* values ("normal" T2*, >20 ms; n = 34). TM patients show significant, uniform decrease in circumferential and radial strain (P < 0.05), and a remarkable reduction in end-systolic rotation, both global, and for all segments (P < 0.001). No significant differences were found between the low- and the normal T2* group either in regional strains and rotation or in standard echocardiographic and CMR parameters. Spearman's correlation coefficient shows no significant correlation between myocardial strains, rotation and cardiac T2* values. In conclusion, our results are in accordance with recent evidence that myocardial iron overload is not the only mechanism underlying iron cardiomyopathy in TM. Strain imaging can predict subclinical myocardial dysfunction irrespective of CMR-T2* values, although it cannot replace CMR-T2* in assessing cardiac iron overload. Finally, it might be useful to appropriately time cardioactive treatment.