Patients' Views of Cardiac Computed Tomography Angiography Compared With Conventional Coronary Angiography

Modified calcium subtraction in dual-energy CT angiography of the lower extremity runoff: impact on diagnostic accuracy for stenosis detection

OBJECTIVES

To investigate the diagnostic accuracy of a modified three-material decomposition calcium subtraction (CS) algorithm for the detection of arterial stenosis in dual-energy CT angiography (DE-CTA) of the lower extremity runoff compared to standard image reconstruction, using digital subtraction angiography (DSA) as the reference standard.

METHODS

Eighty-eight patients (53 males; mean age, 65.9 ± 11 years) with suspected peripheral arterial disease (PAD) who had undergone a DE-CTA examination of the lower extremity runoff between May 2014 and May 2015 were included in this IRB-approved, HIPAA-compliant retrospective study. Standard linearly blended and CS images were reconstructed and vascular contrast-to-noise ratios (CNR) were calculated. Two independent observers assessed subjective image quality using a 5-point Likert scale. Diagnostic accuracy for ≥ 50% stenosis detection was analyzed in a subgroup of 45 patients who had undergone additional DSA. Diagnostic accuracy parameters were estimated with a random-effects logistic regression analysis and compared using generalized estimating equations.

RESULTS

CS datasets showed higher CNR (15.3 ± 7.3) compared to standard reconstructions (13.5 ± 6.5, p < 0.001). Both reconstructions showed comparable qualitative image quality scores (CS, 4.64; standard, 4.57; p = 0.220). Diagnostic accuracy (sensitivity, specificity, positive and negative predictive values) for CS reconstructions was 96.5% (97.5%, 95.6%, 90.9%, 98.1) and 93.1% (98.8%, 90.4%, 82.3%, 99.1%) for standard images.

CONCLUSIONS

A modified three-material decomposition CS algorithm provides increased vascular CNR, equivalent qualitative image quality, and greater diagnostic accuracy for the detection of significant arterial stenosis of the lower extremity runoff on DE-CTA compared with standard image reconstruction.

KEY POINTS

• Calcified plaques may lead to overestimation of stenosis severity and false positive results, requiring additional invasive digital subtraction angiography (DSA). • A modified three-material decomposition algorithm for calcium subtraction provides greater diagnostic accuracy for the detection of significant arterial stenosis of the lower extremity runoff compared with standard image reconstruction. • The application of this algorithm in patients with heavily calcified vessels may be helpful to potentially reduce inconclusive CT angiography examinations and the need for subsequent invasive DSA.

Acceptance of Combined Coronary CT Angiography and Myocardial CT Perfusion versus Conventional Coronary Angiography in Patients with Coronary Stents--Intraindividual Comparison

Objectives

To evaluate how well patients with coronary stents accept combined coronary computed tomography angiography (CTA) and myocardial CT perfusion (CTP) compared with conventional coronary angiography (CCA).

Background

While combined CTA and CTP may improve diagnostic accuracy compared with CTA alone, patient acceptance of CTA/CTP remains to be defined.

Methods

A total of 90 patients with coronary stents prospectively underwent CTA/CTP (both with contrast agent, CTP with adenosine) and CCA as part of the CARS-320 study. In this group, an intraindividual comparison of patient acceptance of CTA, CTP, and CCA was performed.

Results

CTP was experienced to be significantly more painful than CTA (p<0.001) and was associated with a higher frequency of dyspnea (p<0.001). Comparison of CTA/CTP with CCA revealed no significant differences in terms of pain (p = 0.141) and comfort (p = 0.377). Concern before CTA/CTP and CCA and overall satisfaction were likewise not significantly different (p = 0.097 and p = 0.123, respectively). Nevertheless, about two thirds (n = 60, 68%) preferred CTA/CTP to CCA (p<0.001). Moreover, patients felt less helpless during CTA/CTP than during CCA (p = 0.026). Lack of invasiveness and absence of pain were the most frequently mentioned advantages of CTA/CTP over CCA in our patient population.

Conclusions

CCA and combined CTA/CTP are equally well accepted by patients; however, more patients prefer CTA/CTP. CTP was associated with more intense pain than CTA and more frequently caused dyspnea than CTA alone.

Trial Registration

ClinicalTrials.gov NCT00967876

Coronary computed tomography angiography - tolerability of β-blockers and contrast media, and temporal changes in radiation dose

OBJECTIVE

To determine the risk in administering β-blockers, contrast-induced nephropathy (CIN) and the trend in X-ray use, during coronary computed tomography angiography (CCTA).

METHODS

A total of 416 patients were referred for elective CCTA. To achieve a resting heart rate below 60 beats per minute, oral and/or intravenous β-blockers were administered. Using questionnaires, information on the adverse effects of β-blockers was collected from the patients. The levels of s-creatinine and estimated GFR (eGFR) were measured before and after contrast enhanced CCTA. Radiation exposure was compared with the exposure 3 years earlier.

RESULTS

There was no significant difference in the symptoms (dizziness, lipothymia and palpitations) between patients with and patients without β-blocker pretreatment. Compared to baseline values, the decrease in s-creatinine was not significant (75.2 vs. 74.6 μmol/L, p = 0.09), while the increase in eGFR was not significant (78 vs. 79 mL/min, p = 0.17). Also, subgroups of patients with hypertension, hypercholesterolemia, diabetes or pre-existing slight impairment in renal function did not develop CIN. The mean radiation exposure decreased from 17.5 to 6.7 mSv, p < 0.0001.

CONCLUSIONS

In terms of the side effects of β-blockers and contrast media, there were no short term complications to CCTA. Furthermore, the radiation dose has been dramatically diminished over the last three years.

Patient preferences for coronary computed tomography angiography versus conventional catheter angiography for the diagnosis of coronary artery disease

RATIONALE AND OBJECTIVES

The aims of the study were: 1) to assess the baseline health-related quality of life (HRQOL) of patients with coronary artery disease (CAD) using the standard gamble; 2) to evaluate and compare patients' preference for catheter versus computed tomography (CT) coronary angiography using the wait tradeoff (WTO) and rating scales; and 3) to calculate test disutility for catheter and CT coronary angiography.

MATERIALS AND METHODS

Thirty patients with CAD who underwent both CT and catheter angiography were interviewed by telephone within 6 months of testing. Patients were asked about their baseline symptoms and quality of life, their experience preparing for both CT and catheter angiography, their desire to undergo CT or catheter angiography, and immediate treatment versus having a waiting period between test results and treatment for a hypothetical "ideal test" with no side effects. Test disutility for CT and catheter angiography were calculated and compared.

RESULTS

The mean and median baseline HRQOL utility values were 0.72 and 0.91. The patients were willing to wait a mean (median) time of 12 (3) days after the ideal test for the test results to avoid undergoing CT angiography. They were willing to wait a mean (median) of 7 (3) days after the ideal test for test results, to avoid undergoing catheter angiography. There was no significant difference between waiting times or between patients' rating for their experience preparing for the two tests. Test disutility for CT angiography was 1.30 quality-adjusted life days (QALD) versus 2.16 QALD for catheter angiography (P > .05).

CONCLUSION

There was no significant difference in patient preference and test disutility between CT and catheter angiography in our small series. Future rigorously planned and adequately powered studies are required to confirm these findings in larger patient populations.