Sung Min Ko

Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: comparison with cardiac magnetic resonance imaging and conventional coronary angiography

ObjectiveTo evaluate the feasibility and diagnostic accuracy of adenosine-stress dual-energy computed tomography (DECT) for detecting haemodynamically significant stenosis causing reversible myocardial perfusion defect (PD) compared with stress perfusion magnetic resonance imaging (SP-MRI) and conventional coronary angiography (CCA).MethodsFifty patients with known coronary artery disease (CAD) detected by dual-source CT (DSCT) were investigated by contrast-enhanced, stress DECT with high- and low-energy x-ray spectra settings during adenosine infusion. A colour-coded iodine map was used for evaluation of myocardial PDs compared with rest DSCT perfusion images. Reversible myocardial PDs according to the stress DECT/rest DSCT were compared with SP-MRI on a segmental basis and CCA on a vascular territorial basis.ResultsA total of 697 myocardial segments and 123 vascular territories of 41 patients were analysed. Three hundred one segments and 72 vascular territories in 38 patients showed reversible PDs on stress DECT. Stress DECT had 89% sensitivity, 78% specificity and 82% accuracy for detecting segments with reversible PDs seen on SP-MRI (n = 28). Compared with CCA (n = 41), stress DECT had 89% sensitivity, 76% specificity and 83% accuracy for the detection of vascular territories with reversible myocardial PDs that had haemodynamically relevant CAD.ConclusionAdenosine stress DECT can identify stress-induced myocardial PD in patients with CAD.

Diagnostic Performance of Combined Noninvasive Anatomic and Functional Assessment With Dual-Source CT and Adenosine-Induced Stress Dual-Energy CT for Detection of Significant Coronary Stenosis

OBJECTIVE The purpose of our study was to prospectively evaluate the incremental diagnostic value of combined dual-source coronary CT angiography (CTA) and CT myocardial perfusion imaging (MPI) for the detection of significant coronary stenoses. SUBJECTS AND METHODS Forty-five patients with known coronary artery disease detected by dual-source coronary CTA were investigated by adenosine-induced stress dual-source CTA and conventional coronary angiography. Analysis was performed in three steps: classification of coronary stenosis severity using dual-source coronary CTA, identification of myocardial perfusion defects using rest and stress CT MPI, and reclassification of coronary stenosis severity according to combined dual-source coronary CTA and CT MPI. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of dual-source coronary CTA before and after CT MPI were calculated on a per-vessel basis compared with conventional coronary angiography as the standard of reference. RESULTS Dual-source coronary CTA revealed 87 significantly stenotic vessels in 45 patients. Conventional coronary angiography revealed significant stenoses in 73 vessels in 42 patients. CT MPI showed myocardial perfusion defects in 81 vessel territories in 43 patients. After the CT MPI analysis, dual-source coronary CTA identified significant stenoses in 77 coronary vessels in 42 patients. Sensitivity, specificity, PPV, and NPV of the dual-source coronary CTA on a per-vessel basis before CT MPI were 91.8%, 67.7%, 73.6%, and 87.5%, respectively, and after CT MPI were 93.2%, 85.5%, 88.3%, and 91.4%, respectively. The area under the receiver operating characteristic curve increased significantly from 0.798 to 0.893 (p = 0.004). CONCLUSION Combined dual-source coronary CTA and CT MPI provides incremental diagnostic value compared with dual-source coronary CTA alone for the detection of significant coronary stenoses.

Myocardial Bridging of the Left Anterior Descending Coronary Artery: Depiction Rate and Morphologic Features by Dual-Source CT Coronary Angiography

Objective To evaluate the depiction rate and morphologic features of myocardial bridging (MB) of the left anterior descending coronary artery (LAD) using dual-source CT (DSCT). Materials and Methods CT scans from a total of 1,353 patients who underwent DSCT were reviewed retrospectively for LAD-MB. Seventy-eight patients were excluded due to poor image quality or poor enhancement of the coronary artery. The length and depth of the MB were analyzed and classified as superficial or deep with respect to the depth (≤ 1 or > 1 mm) of the LAD tunneled segment. Superficial MB was subdivided into complete or incomplete types according to full or partial encasement of the myocardium. Results Of the 1,275 patients included in this study, 557 cases of MB were found from 536 patients (42%). Superficial MB was observed in 368 of 557 (66%) cases, and deep MB was seen in 189 of 557 (34%) cases. Superficial MB showed 2 types: complete (128 of 368, 35%) and incomplete (240 of 368, 65%). The mean length of a tunneled segment for superficial MB was 16.4 ± 8.6 mm. The mean length and depth of a tunneled segment for deep MB were 27.6 ± 12.8 mm and 3.0 ± 1.4 mm, respectively. The incidence of atherosclerotic plaques in a 2-cm-long segment proximal to MB was 16%. Conclusion The depiction rate of LAD-MB using DSCT in a large series of patients was 42%, with two-thirds of MB segments being the superficial type.

Diagnostic Performance of Dual-Energy CT Stress Myocardial Perfusion Imaging: Direct Comparison With Cardiovascular MRI

OBJECTIVE The purpose of this study was to assess the diagnostic performance of stress perfusion dual-energy CT (DECT) and its incremental value when used with coronary CT angiography (CTA) for identifying hemodynamically significant coronary artery disease. SUBJECTS AND METHODS One hundred patients with suspected or known coronary artery disease without chronic myocardial infarction detected with coronary CTA underwent stress perfusion DECT, stress cardiovascular perfusion MRI, and invasive coronary angiography (ICA). Stress perfusion DECT and cardiovascular stress perfusion MR images were used for detecting perfusion defects. Coronary CTA and ICA were evaluated in the detection of ≥50% coronary stenosis. The diagnostic performance of coronary CTA for detecting hemo-dynamically significant stenosis was assessed before and after stress perfusion DECT on a per-vessel basis with ICA and cardiovascular stress perfusion MRI as the reference standard. RESULTS The performance of stress perfusion DECT compared with cardiovascular stress perfusion MRI on a per-vessel basis in the detection of perfusion defects was sensitivity, 89%; specificity, 74%; positive predictive value, 73%; negative predictive value, 90%. Per segment, these values were sensitivity, 76%; specificity, 80%; positive predictive value, 63%; and negative predictive value, 88%. Compared with ICA and cardiovascular stress perfusion MRI per vessel territory the sensitivity, specificity, positive predictive value, and negative predictive value of coronary CTA were 95%, 61%, 61%, and 95%. The values for stress perfusion DECT were 92%, 72%, 68%, and 94%. The values for coronary CTA and stress perfusion DECT were 88%, 79%, 73%, and 91%. The ROC AUC increased from 0.78 to 0.84 (p=0.02) with the use of coronary CTA and stress perfusion DECT compared with coronary CTA alone. CONCLUSION Stress perfusion DECT plays a complementary role in enhancing the accuracy of coronary CTA for identifying hemodynamically significant coronary stenosis.

Bicuspid Aortic Valve: Spectrum of Imaging Findings at Cardiac MDCT and Cardiovascular MRI

OBJECTIVE Cardiac MDCT and cardiovascular MRI have become widely used for the evaluation of cardiovascular disease, including aortic valve disease. The purpose of this article is to present the cardiac MDCT and cardiovascular MRI findings of bicuspid aortic valve, its various complications, and other congenital cardiovascular malformations. CONCLUSION Radiologists should be aware of the clinical significance and the varied appearance of bicuspid aortic valve at cardiac MDCT and cardiovascular MRI.

Assessment of global left ventricular function with dual-source computed tomography in patients with valvular heart disease

Background Left ventricular (LV) function is a vital parameter for prognosis, therapy guidance, and follow-up of cardiovascular disease. Dual-source computed tomography (DSCT) provides an accurate analysis of global LV function. Purpose To assess the performance of DSCT in the determination of global LV functional parameters in comparison with cardiovascular magnetic resonance (CMR) and two-dimensional transthoracic echocardiography (2D-TTE) in patients with valvular heart disease (VHD). Material and Methods A total of 111 patients (58 men, mean age 49.9 years) with known VHD and who underwent DSCT, 2D-TTE, and CMR a period of 2 weeks before undergoing valve surgery were included in this study. LV end-systolic volume (ESV), end-diastolic volume (EDV), stroke volume (SV), and ejection fraction (EF) were calculated by DSCT using the threshold-based technique, by 2D-TTE using a modified Simpsons method, and by CMR using Simpsons method. Agreement for parameters of LV global function was determined with the Pearsons correlation coefficient (r) and Bland-Altman analysis. All the DSCT and CMR data-sets were assessed independently by two readers. Results Fifty of the total 111 patients had aortic VHD, 29 patients had mitral VHD, and 32 patients had mixed aortic and mitral VHD. An excellent inter-observer agreement was seen for the assessment of global LV function using DSCT (r = 0.910–0.983) and CMR (r = 0.854–0.965). An excellent or good correlation (r = 0.93, 0.95, 0.87, and 0.71, respectively, P < 0.001) was noted between the DSCT and 2D-TTE values for EDV, ESV, SV, and EF. EDV (33.7 mL, P < 0.001), ESV (12.1 mL, P < 0.001), SV (21.2 mL, P < 0.001), and EF (1.6%, P = 0.019) were significantly overestimated by DSCT when compared with 2D-TTE. An excellent correlation (r = 0.96, 0.97, 0.91, and 0.94, respectively, P < 0.001) between DSCT and CMR was seen in the evaluation of EDV, ESV, SV, and EF. EDV (15.9 mL, P < 0.001), ESV (7.3 mL, P < 0.001), and SV (8.5 mL, P < 0.001) were significantly underestimated, but EF (1.1%, P = 0.002) was significantly overestimated by DSCT when compared with CMR. Conclusion Our study showed that DSCT measurements of global LV function using the threshold-based technique were highly reproducible and compared more favorably with CMR measurements using Simpsons method than those of 2D-TTE using the modified Simpsons method. DSCT enables accurate quantification of global LV function in patients with VHD.

Multi-modality imaging for the assessment of myocardial perfusion with emphasis on stress perfusion CT and MR imaging

Abstract High-quality and non-invasive diagnostic tools for assessing myocardial ischemia are necessary for therapeutic decisions regarding coronary artery disease. Myocardial perfusion has been studied using myocardial contrast echo perfusion, single-photon emission computed tomography, positron emission tomography, cardiovascular magnetic resonance, and, more recently, computed tomography. The addition of coronary computed tomography angiography to myocardial perfusion imaging improves the specificity and overall diagnostic accuracy of detecting the hemodynamic significance of coronary artery stenosis. This study reviews the benefits, limitations, and imaging findings of various imaging modalities for assessing myocardial perfusion, with particular emphasis on stress perfusion computed tomography and cardiovascular magnetic resonance imaging.

Cardioembolic Origin in Patients With Embolic Stroke: Spectrum of Imaging Findings on Cardiac MDCT

OBJECTIVE The purpose of this article is to show various cardiac MDCT findings of a cardioembolic origin in patients with embolic stroke. CONCLUSION Cardiac MDCT is an emerging technique for the identification and assessment of a cardioembolic origin in patients with embolic stroke. In the near future, it will play an increasing role in the assessment of patients with a suspected embolic stroke.

Linear Fat Deposition in the Middle Layer of the Left Ventricular Myocardium: Computed Tomographic Findings

We report here a case of streaky fat deposition in the middle layer of the left ventricular myocardium, without any underlying etiology, and this was seen on computed tomography coronary angiography. This report suggests that left ventricular middle layer fat deposition should be investigated in order to determine its etiology, the pathogenesis and the prognosis.

Background uptake of breast-specific gamma imaging: correlation with mammographic breast density and background enhancement of breast MRI

PURPOSE To investigate the relationship between background uptake of breast-specific gamma imaging (BSGI) mammographic breast density and background enhancement of breast magnetic resonance imaging (MRI). MATERIALS AND METHODS The level and texture of background uptake of BSGI, mammographic breast density, and background enhancement of breast MRI are retrospectively reviewed in 104 patients. RESULTS Heterogeneous and increased background uptake of BSGI was significantly correlated with high mammographic breast density (P=.016, P=.001) and increased background enhancement of breast MRI (P=.015, P=.017). CONCLUSION Interpreting BSGI of women showing high mammographic breast density or background enhancement of breast MRI needs to be carried out with caution.