Different perfusion pattern between acute and chronic pulmonary thromboembolism: evaluation with two-phase dual-energy perfusion CT.

OBJECTIVE: The purpose of this study was to evaluate whether two-phase dual-energy CT can differentiate between lung perfusion patterns of patients with chronic pulmonary thromboembolism (PTE) and those of patients with acute PTE. SUBJECTS AND METHODS: A total of 114 patients clinically suspected to have PTE were prospectively enrolled. All patients underwent dual-energy CT at pulmonary artery (PA) and delayed phases. Of 68 patients diagnosed with PTE on CT, 42 were finally included. Iodine-related attenuation values (IRAs) were measured in PA and delayed phases for each lung segment, and IRA change ratios were calculated using the formula 100% × [(IRA of delayed phase) - (IRA of PA phase)]/(IRA of PA phase). RESULTS: Among the 42 patients (19 men and 23 women; mean age, 60.3 ± 13.2 years; range, 28-82 years), 24 had a diagnosis of acute PTE and 18 of chronic PTE. Those segments with both perfusion and filling defects (n = 143) in patients with acute PTE showed no significant changes of mean IRA between PA and delayed phases, whereas the segments from patients with chronic PTE (n = 94) showed significantly increased IRA on delayed phase as compared with PA phase. The mean IRA change ratios in acute and chronic PTE were -3.14% and 191.9%, respectively (p < 0.0001). CONCLUSION: Chronic PTE segments were significantly more enhanced on the delayed phase of two-phase dual-energy CT images than were acute PTE segments, possibly resulting from more extensive systemic collateral formation in chronic PTE. Two-phase dual-energy CT can be used to differentiate distinct regional perfusion patterns between acute and chronic PTE.

The effect of pulmonary blood flow changes on oxygen-enhanced lung magnetic resonance imaging.

In this study, we investigated the effects of changes in pulmonary blood flow on oxygen-enhanced lung magnetic resonance imaging. Increased pulmonary blood flow was produced by intravenous infusion of sildenafil (0.2 mg/kg) in 10 New Zealand white rabbits. Decreased pulmonary blood flow was produced by single subcutaneous injection of monocrotaline (60 mg/kg). A velocity-encoded cine magnetic resonance imaging for pulmonary blood flow and an oxygen-enhanced lung magnetic resonance imaging were performed at baseline, during sildenafil infusion, and after monocrotaline injection. We compared the baseline data to those obtained during sildenafil infusion and after monocrotaline injection for pulmonary blood flow changes and signal intensity enhancement ratios of oxygen-enhanced lung magnetic resonance imaging. Wilcoxon's signed rank test was used for statistical analysis. There was a significant difference between pulmonary blood flow at baseline (418.6±108.9 mL/min) and after sildenafil (491.9±118.0 mL/min; P=0.005) or between pulmonary blood flow at baseline and after monocrotaline administration (356.3±85.8 mL/min; P=0.017). However, there was no significant difference between the signal intensity enhancement ratios at baseline (23.8±11.4%) and after sildenafil (24.0±7.9%; P=0.953) or the signal intensity enhancement ratios at baseline and after monocrotaline administration (22.7±10.3%; P=0.374). Changes in pulmonary blood flow had little effect on the signal intensity enhancement ratio of oxygen-enhanced lung magnetic resonance imaging.

Anomalous origin of the right coronary artery from the left coronary sinus with an interarterial course: subtypes and clinical importance.

PURPOSE: To classify anomalous origins of the right coronary artery (RCA) from the left coronary sinus (AORL) with an interarterial course into two subtypes and to evaluate the clinical importance of each. MATERIALS AND METHODS: Institutional review board approval was obtained for this retrospective study, and informed consent was waived. Through a retrospective review of 22,925 consecutive cardiac computed tomographic (CT) scans, 124 cases of AORL with an interarterial course were identified. These anomalies were classified into two subtypes according to the location of the anomalous RCA ostium: high interarterial course (between the aorta and the pulmonary artery) and low interarterial course (between the aorta and the right ventricular outflow tract). The clinical records were evaluated, and differences in prevalence of typical angina and major adverse cardiac events (MACEs) between the subtypes were analyzed through the χ(2) contingency tables or Fisher exact test. RESULTS: After excluding patients with combined cardiac disease, 87 patients (51 [59%] men, 36 [41%] women; mean age, 56.0 years) were enrolled. Of the 87 patients, 53 had a high interarterial course and 34 had a low interarterial course. A significant difference in the prevalence of typical angina (high [43%] vs low [6%], P = .001) and MACE (high [28%] vs low [6%], P = .012) was observed between the two subtypes. For patients with a high interarterial course, the odds ratio for typical angina was 12.3 (95% confidence interval: 2.7, 56.6), and the odds ratio for MACE was 6.3 (95% confidence interval: 1.3, 29.7). CONCLUSION: The prevalence of typical angina and that of MACE were significantly higher in patients with a high interarterial course than in those with a low interarterial course.

Assessment of atherosclerotic plaques in a rabbit model by delayed-phase contrast-enhanced CT angiography: comparison with histopathology.

The aim of this study was to compare delayed-phase computed tomography angiography (CTA) attenuation values with histopathology, in ability to differentiate between fibrous and lipid-rich plaques in an experimental rabbit model. Twelve atherosclerotic rabbits underwent CTA of the abdominal aorta. The scan protocol included early-phase scans (EP), delayed scans at 90 s after contrast injection (DP(90s)), delayed scans at 10 min after contrast injection (DP(10min)), and delayed scan with saline infusion (DP(Saline)). Plaque composition was analyzed by histopathology (% of lipid-rich, fibrous and macrophage areas) and CT attenuation values in Hounsfield units. Using histopathology as the reference standard (n = 119), the overall sensitivity, specificity and accuracy of 64-slice CTA for the detection of plaques was 59, 100 and 79% for the EP scans; 88, 100 and 94% for the DP(90s) scans; 81, 100 and 90% for the DP(10min) scans; and 53, 100 and 76% for the DP(Saline) scans. CT density measurements showed a substantial overlap between fibrous and lipid-rich plaques, and poor correlations with the percentage of macrophage areas in both fibrous and lipid-rich plaques (r = 0.408, and r = 0.333). In delayed-phase 64-slice CTA, DP(90s) images have the best diagnostic performance for the detection of aortic plaques.

The usefulness of delayed contrast-enhanced cardiovascular magnetic resonance imaging in differentiating cardiac tumors from thrombi in stroke patients.

The objectives of this study were to evaluate the diagnostic value of delayed-enhancement cardiovascular magnetic resonance (DE-CMR) imaging in differentiating cardiac tumors from thrombi in patients with suspected cardio-embolic stroke. Two radiologists blinded to the study protocol retrospectively evaluated MR images of 22 patients (12 men and 10 women; mean age 59.2 years) that had recently experienced a stroke and undergone CMR. Six cardiac tumors and 16 thrombi were confirmed on surgery or follow-up examinations. On DE-CMR, a tumor was defined as an intracardiac mass showing post-contrast enhancement, and a thrombus was defined as an intracardiac mass showing black signal intensity (SI) without post-contrast enhancement. The mean SI in regions of interest in the normal myocardium and cardiac mass were measured using cine-CMR and DE-CMR. Visual assessment of enhancement characteristics of cardiac masses on DE-CMR could accurately differentiate cardiac tumors from thrombi in all cases. On cine-CMR, the mean SI ratios for tumors and thrombi were 1.45 ± 0.45 (range, 1.12-2.16) and 1.39 ± 0.33 (range, 0.87-2.09), respectively (P = 0.745). On DE-CMR, the mean SI ratios for tumors and thrombi were 5.65 ± 2.96 (range, 2.98-9.92) and 1.06 ± 0.43 (range, 0.67-1.95), respectively (P < 0.001). DE-CMR is a non-invasive modality for detecting intra-cardiac mass can differentiate tumors from thrombi in cardio-embolic stroke patients.

Analysis of tumor markers in the cytological fluid obtained from computed tomography-guided needle aspiration biopsy for the diagnosis of non-small cell lung cancer.

PURPOSE: The aim of this study was to prospectively assess whether analysis of the tumor markers cytokeratin 19 fragments (CYFRA 21-1), carcinoembryonic antigen (CEA), and squamous cell carcinoma (SCC) antigen in cytological fluid can improve the performance of computed tomography (CT)-guided needle aspiration biopsy (NAB) in the diagnosis of non-small cell lung cancer (NSCLC). METHODS: A total of 100 patients (men:women = 41:59, mean age: 63 years) with suspected malignant pulmonary lesions were prospectively enrolled for CT-guided NAB procedures. Levels of CYFRA 21-1, CEA, and SCC in the cytological fluid were measured by immunoradiometric assays. The cutoff value for tumor markers was selected on the basis of best accuracy through receiver operating characteristic curves. The sensitivity and areas under the curve (AUC) of NAB alone were compared with those of NAB combined with cytological tumor markers (CYFRA 21-1, CEA, and SCC). RESULTS: Among 100 patients, 71 (71%) had NSCLC and 29 (29%) had benign lesions. The sensitivity, specificity, and accuracy for diagnosing NSCLC were 85.7%, 100%, and 89%, respectively, for NAB alone. The sensitivity increased significantly for NAB combined with a tumor marker compared with NAB alone (100% for CYFRA 21-1, 92.9% for CEA, and 94.2% for SCC; p = 0.001, p = 0.025, and p = 0.014, respectively). The AUC of NAB with CYFRA 21-1 was significantly larger than the AUC of NAB alone (p = 0.001). CONCLUSION: Evaluation of tumor markers CYFRA 21-1, CEA, and SCC in the cytological fluid can improve the diagnostic performance of CT-guided NAB for NSCLC. Of these markers, CYFRA 21-1 is the most useful cytological tumor marker.

Dual-enhanced cardiac CT for detection of left atrial appendage thrombus in patients with stroke: a prospective comparison study with transesophageal echocardiography.

BACKGROUND AND PURPOSE: A noninvasive method with high reliability and accuracy comparable to transesophageal echocardiography for identification of left atrial appendage thrombus would be of significant clinical value. The aim of this study was to assess the diagnostic performance of a dual-enhanced cardiac CT protocol for detection of left atrial appendage thrombi and for differentiation between thrombus and circulatory stasis in patients with stroke. METHODS: We studied 83 consecutive patients with stroke (56 men and 27 women; mean age, 62.6 years) who had high risk factors for thrombus formation and had undergone both dual-source CT and transesophageal echocardiography within a 3-day period. CT was performed with prospective electrocardiographic gating, and scanning began 180 seconds after the test bolus. RESULTS: Among the 83 patients, a total of 13 thrombi combined with spontaneous echo contrast and 14 spontaneous echo contrasts were detected by transesophageal echocardiography. All 13 thrombi combined with spontaneous echo contrast were correctly diagnosed on CT. Using transesophageal echocardiography as the reference standard, the overall sensitivity and specificity of CT for the detection of thrombi and circulatory stasis in the left atrial appendage were 96% (95% CI, 78% to 99%), and 100% (95% CI, 92% to 100%), respectively. On CT, the mean left atrial appendage/ascending aorta Hounsfield unit ratios were significantly different between thrombus and circulatory stasis (0.15 Hounsfield unit versus 0.27 Hounsfield unit, P=0.001). The mean effective radiation dose was 3.11 mSv. CONCLUSIONS: Dual-enhanced cardiac CT with prospective electrocardiographic gating is a noninvasive and sensitive modality for detecting left atrial appendage thrombus with an acceptable radiation dose.

Low-dose electrocardiography synchronized nonenhanced computed tomography for assessing left atrium and pulmonary veins before radiofrequency catheter ablation for atrial fibrillation.

Recently contrast-enhanced cardiac computed tomography (CT) was found to be useful for imaging the left atrium and pulmonary veins (PVs) before radiofrequency catheter ablation in patients with atrial fibrillation. However, the risks of contrast agent in patients with impaired renal function must be considered. We investigated the accuracy of low-dose electrocardiographically synchronized nonenhanced cardiac CT (NECT) for identifying PV anatomy. One hundred eight consecutive patients who underwent cardiac CT before radiofrequency catheter ablation of atrial fibrillation were included. Nonenhanced cardiac computed tomogram was retrospectively evaluated for each patient by 2 radiologists for the following PV anatomy: conventional pattern, conjoined ostium, and accessory PVs with number and location. Sensitivity and specificity for variations in PVs were calculated using contrast-enhanced cardiac computed tomogram as the reference standard. Detection rates for each variation were also calculated. Twenty-one right PV (RPV) variations and 11 left PV (LPV) variations were observed. NECT showed a high diagnostic performance in detecting variations in PVs for the 2 observers. For RPV variations overall sensitivity was 97.6% and specificity was 96.6%. For LPV variations overall sensitivity was 90.9% and specificity was 97.9%. Overall detection rates for variation between the 2 observers were 97.1% for accessory RPV from the right middle lobe, 100% for 4 ostia with accessory RPV from the right middle lobe and accessory RPV from the superior segment of the right lower lobe, 100% for accessory RPV from the superior segment of the right lower lobe, 88.9% for conjoined ostium of the LPV, and 100% for accessory LPV from the left lingular segment. In conclusion, variations in PV anatomy were detected with great accuracy by NECT.

CT fluoroscopy-guided lung biopsy versus conventional CT-guided lung biopsy: a prospective controlled study to assess radiation doses and diagnostic performance.

OBJECTIVE: We evaluated radiation doses, complication rates, and diagnostic accuracy for CT-guided percutaneous needle aspiration biopsy (NAB) procedures of pulmonary lesions performed with or without fluoroscopic guidance. METHODS: A total of 142 patients were prospectively enrolled to receive CT-guided NAB with (Group I, n = 72) or without (Group II, n = 70) fluoroscopic guidance. Outcome measurements were patient and doctor radiation dose, and complication rate. Sensitivity, specificity and accuracy were calculated based on 123 NAB results. RESULTS: The mean estimated effective patient radiation dose was 6.53 mSv in Group I and 2.72 mSv in Group II (p < 0.001). The mean estimated effective doctor dose was 0.054 mSv in Group I and 0.029 mSv in Group II (p < 0.001). The complication rate was significantly different between the two groups (13.4% versus 31.4%, p = 0.012). Sensitivity, specificity and accuracy for diagnosing pulmonary lesions were 97.8%, 100% and 98.4% in group I and 95.3%, 100% and 89.5% in group II (p > 0.05). CONCLUSIONS: CT fluoroscopy-guided NAB of pulmonary lesions provides high diagnostic accuracy and can be performed with significantly fewer complications. However, radiation exposure to both patient and doctor were significantly higher than conventional CT-guided NAB.

Diagnostic accuracy of 64-slice multidetector computed tomography for selecting coronary artery bypass graft surgery candidates.

OBJECTIVE: The objective of our study was to investigate the diagnostic accuracy of computed tomographic coronary angiography for the selection of candidates for coronary artery bypass graft surgery. METHODS: Institutional review board approval was obtained. We included 172 patients (mean age, 63 years; 127 men and 45 women) with a suspicion of coronary artery disease who underwent both computed tomographic coronary angiography and conventional coronary angiography. We established eligible criteria for coronary artery bypass graft surgery based on American College of Cardiology/American Heart Association practice guidelines: 3-vessel disease, left main coronary artery disease, and left main coronary artery equivalent disease. Results of computed tomographic coronary angiography and conventional coronary angiography were reviewed retrospectively by 2 radiologists and 2 cardiologists who were unaware of the other examiners' findings. Diagnostic performances of computed tomographic coronary angiography were calculated, with conventional coronary angiography as the reference standard. RESULTS: The overall sensitivity, specificity, positive predictive value, and negative predictive value of computed tomographic coronary angiography for the selection of coronary artery bypass graft surgery candidates were 85.9%, 96.0%, 93.8%, and 90.7%, respectively. We also obtained high diagnostic performances for 3-vessel disease (sensitivity, 83.1%; specificity, 96.5%; positive predictive value, 92.5%; negative predictive value, 91.6%), left main coronary artery disease (sensitivity, 94.7%; specificity, 96.7%; positive predictive value, 78.3%; negative predictive value, 99.3%), and left main coronary artery equivalent disease (sensitivity, 100%; specificity, 100%; positive predictive value, 100%; negative predictive value, 100%). CONCLUSIONS: Patients selected as candidates for coronary artery bypass graft surgery with conventional coronary angiography can also be relatively accurately classified by using computed tomographic coronary angiography with 64-slice multidetector computed tomography.

Use of contrast enhancement and high-resolution 3D black-blood MRI to identify inflammation in atherosclerosis.

OBJECTIVES: We investigated the contributing factors for plaque enhancement and examined the relationships between regional contrast enhancement and the inflammatory activity of atherosclerotic plaques in an experimental rabbit model using contrast-enhanced high-resolution 3-dimensional (3D) black-blood magnetic resonance imaging (MRI) in comparison with histopathologic analysis. BACKGROUND: Inflammation plays a critical role in plaque initiation, progression, and disruption. As such, inflammation represents an emerging target for the treatment of atherosclerosis. MRI findings suggest that contrast agent-induced signal enhancement is associated with the degree of macrophage infiltration and neovessels that can be detected in plaque. METHODS: Ten atherosclerotic rabbits and 3 normal control rabbits underwent high-resolution 3D contrast-enhanced black-blood MRI. Magnetic resonance images and the corresponding histopathologic sections were divided into 4 quadrants. Plaque composition was analyzed for each quadrant according to histopathologic criteria (percent of lipid-rich, fibrous, macrophage area and microvessel density) and imaging criteria (enhancement ratio [ER], ER = signal intensity(post)/signal intensity(pre)). Multiple linear regression analysis was performed to determine independent factors for plaque enhancement. RESULTS: A total of 62 noncalcified plaques (n = 248; 156 lipid-rich quadrants and 92 fibrous quadrants) were identified based on histopathologic analysis. Mean ER values were significantly higher in atherosclerotic vessel walls than in normal vessel walls (2.03 ± 0.25 vs. 1.58 ± 0.15; p = 0.017). The mean ER values were significantly higher in lipid-rich quadrants compared with the fibrous quadrants (2.14 ± 0.31 vs. 1.84 ± 0.21; p = 0.001). Mean ER values were significantly higher in macrophage-rich plaques compared with the macrophage-poor plaques (2.21 ± 0.28 vs. 1.81 ± 0.22; p = 0.001). Using multiple regression analysis, macrophage area and microvessel density were associated independently with ER values that reflected plaque enhancement (p < 0.001). CONCLUSIONS: Contrast-enhanced high-resolution 3D black-blood MRI may be an efficient method to detect plaque inflammation.

Radiologic findings of lung lobe torsion in reconstructed multidetector computed tomography image lead to early detection.

Torsion of the remaining lung lobe after lobectomy is a rare complication, and sometimes, diagnosis can be difficult. But early detection is important to prevent resection and fatal complication. We present a case of left lower lobe torsion with reconstructed image of multidetector computed tomography (MDCT) findings, which propose a possibility of early detection on retrospective review after surgical reduction. Multiplanar reconstruction of MDCT image, 3-dimensional CT angiography, and CT bronchography could provide important diagnostic clues.

Coronary artery anomalies: detection on coronary artery calcium scoring scan.

OBJECTIVE: The objective of this study was to evaluate the accuracy of coronary artery calcium scanning in identifying coronary anomalies and potentially high-risk interarterial courses. MATERIALS AND METHODS: Ninety-five consecutive patients who were diagnosed with a coronary anomaly on CT coronary angiography were enrolled, and 95 age- and sex-matched individuals in whom any coronary anomalies were excluded on CT coronary angiography were used as control subjects (total, 190 patients; 106 men and 84 women; mean age, 58 +/- 12 years). The coronary artery calcium scan for each patient was retrospectively evaluated by three radiologists for the presence of coronary anomalies and the presence of an interarterial course in cases of suspected anomaly. Interobserver agreement was assessed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of a coronary artery calcium scan for coronary anomalies and their interarterial courses were calculated, with CT coronary angiography as the reference standard. RESULTS: Almost perfect interobserver agreement was achieved in evaluating coronary anomalies and interarterial courses (kappa = 0.81 and 0.92, respectively). We achieved a high grade of diagnostic performance of coronary artery calcium scanning in detecting coronary anomalies (sensitivity, 79-80%; specificity, 95-98%; PPV, 94-97%; and NPV, 82-83%) and interarterial courses (sensitivity, 88-91%; specificity, 95-97%; PPV, 84-91%; and NPV, 97%). CONCLUSION: Coronary anomalies and interarterial courses were detected with great accuracy on coronary artery calcium scans.

Computed tomographic fluoroscopy-guided needle aspiration biopsy as a second biopsy technique after indeterminate transbronchial biopsy results for pulmonary lesions: comparison with second transbronchial biopsy.

OBJECTIVE: The purpose of this study was to compare the diagnostic performance of computed tomographic (CT) fluoroscopy-guided percutaneous transthoracic needle aspiration biopsy (NAB) and transbronchial lung biopsy (TBLB) after indeterminate bronchoscopy in patients with suspected malignant pulmonary lesions. METHODS: We included 77 patients who underwent CTF-NAB (n = 53) or TBLB (n = 24) as a second biopsy for pulmonary lesions because of inconclusive pathologic results on initial TBLB. Sensitivity, specificity, and diagnostic accuracy were calculated and compared between the 2 groups using the Fisher exact test. Sensitivity and diagnostic accuracy were also compared according to lesion depth (central vs peripheral), lesion location (upper vs lower), and lesion size (<2 vs 2-3 vs >3 cm). RESULTS: There were 50 (65%) malignant and 27 (35%) benign lesions. The overall sensitivity, specificity, and accuracy for diagnosing pulmonary lesions were 84%, 100%, and 91% for NAB and 50%, 100%, and 63% for TBLB. The sensitivity and accuracy for diagnosing pulmonary lesions were significantly different between the 2 groups (P = 0.019, and P = 0.008). The sensitivity and accuracy of TBLB for diagnosing lesions was significantly different according to the lesion size (P = 0.025, and P = 0.048). CONCLUSION: A second biopsy using CT fluoroscopy-guided NAB is a useful diagnostic modality for exact diagnosis of pulmonary lesions in cases of inconclusive pathologic results on initial TBLB.

Delayed enhancement magnetic resonance imaging is a significant prognostic factor in patients with non-ischemic cardiomyopathy.

BACKGROUND: Delayed enhancement (DE) on cardiac magnetic resonance imaging (CMR) is a marker of myocardial fibrosis. The absence of DE in CMR is a predictor of left ventricular (LV) functional improvement in patients with non-ischemic cardiomyopathy (NICM), so in the present study it was investigated whether presence of DE has prognostic significance in patients with NICM at long-term follow-up. METHODS AND RESULTS: The 79 patients (56.4+/-13.5 years, 48 males) with NICM (LV ejection fraction <35%, no significant coronary artery disease) were monitored for occurrence of cardiac events. CMR was performed to assess DE. Cardiac events were defined as rehospitalization (because of worsening of heart failure), cardiac transplantation or death. There were 37 patients without and 42 patients with DE. The mean follow-up duration was 19+/-10 months. There was 1 event (2.7%, 1 rehospitalization) in the DE (-) group, whereas 13 events (30.9%, 1 death, 1 transplantation, 11 rehospitalizations) occurred in the DE (+) group. The event-free survival was significantly longer in the DE (-) group than in the DE (+) group (38.9+/-1.0 vs 28.4+/-2.7 months, P<0.01). Multivariate regression analysis revealed that presence of DE was the most potent, independent predictor of cardiac events (hazard ratio 8.06, confidence interval 1.03+/-63.41, P<0.05). CONCLUSIONS: The presence of DE in CMR is a significant predictor of future cardiac events in patients with NICM.

Evaluation of coronary artery in-stent restenosis by 64-section computed tomography: factors affecting assessment and accurate diagnosis.

PURPOSE: To determine factors affecting the ability of 64-multislice computed tomography (MSCT) to detect, assess, and accurately diagnose significant coronary arterial in-stent restenosis (ISR). MATERIALS AND METHODS: The institutional review board approved this study and waived informed consent. Sixty patients underwent CT coronary angiography using 64-MSCT, after implantation of coronary artery stents (n=91). We assessed diagnostic accuracy for ISR with CT in comparison with conventional coronary angiography as the gold standard, visually and with measurement of in-stent coronary lumen density. Possible factors that influenced the diagnostic performance of CT were evaluated, which included image quality (IQ), stent characteristics, and location. RESULTS: Sixty-nine stents (75.8%) were assessable. Low IQ, location in the left circumflex coronary artery, and narrow stent diameter were associated with poor assessment (P<0.05). In stents that could be assessed, sensitivity, specificity, positive predictive value, and negative predictive value of 64-MSCT were 90.0%, 73.5%, 58.1%, and 94.7%, respectively, for significant ISR. The diagnostic accuracy in assessable stents showed a significant increase with better IQ, thinner strut thickness, and nondrug eluting stent. False-positive diagnoses of ISR by CT were explained by coronary lumen density measurements. CONCLUSIONS: Evaluation of stents by 64-MSCT is not recommended in stents with diameters of < or = 2.75 mm or stents located at the left circumflex coronary artery. The diagnostic accuracy of 64-MSCT is affected by IQ and strut thickness in assessable stents. Significant ISR can be excluded with high reliability in selected patients.

Quantification of regional calcium burden in chronic total occlusion by 64-slice multi-detector computed tomography and procedural outcomes of percutaneous coronary intervention.

BACKGROUND: One of the most important reasons for failure of percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) is calcified plaque, which either prevents passage of guide wire or ruptures after balloon inflation. We sought to evaluate whether quantified calcium contents of CTO on multi-detector computed tomography (MDCT) correlate with immediate procedural outcomes. METHODS: Sixty-four patients with 72 CTO lesions who underwent 64-slice MDCT prior to PCI were investigated. The lesions were divided into 2 groups according to procedural outcomes (55 lesions with PCI-success group, 17 lesions with PCI-failure group). Clinical, angiographic and MDCT parameters, including regional calcium volume (RCaV), regional calcium score (RCaS), regional calcium equivalent mass (RCaEq), and relative calcium area at the most calcified cross section of CTO (%CaS/CSA), were compared between the two groups. RESULTS: The duration of CTO was shorter in PCI-success group than PCI-failure group (7.16 ± 10.5 vs 15.59 ± 14.92 months, p=0.011), and the procedural success rate was 76.3%. Regional calcium-related parameters (RCaV 52.86 ± 58.39 vs 7.26 ± 15.27 mm(3), p<0.001; RCaS 72.71 ± 78.4 vs 9.66 ± 20.2, p<0.001; RCaEq 12.58 ± 12.97 vs 1.84 ± 3.716 mgCaHA, p<0.001; %CaS/CSA 53.9 ± 20.3 vs 30.4 ± 17.1%, p=0.009) in the occluded segment were higher and the occlusion length was longer (37.44 ± 27.48 vs 22.00 ± 18.04 mm, p<0.021) in PCI-failure group compared to PCI-success group. Multivariate regression analysis showed that only %CaS/CSA was a significant determinant of PCI-failure. CONCLUSIONS: Precise quantification of regional calcification and measurement of the occluded segment by high resolution MDCT can deliver important information for predicting procedural outcomes in PCI of CTO.

Quantification and characterization of obstructive coronary plaques using 64-slice computed tomography: a comparison with intravascular ultrasound.

PURPOSE: The aim of this study was to determine the diagnostic accuracy of 64-slice computed tomography (CT) coronary angiography in the quantification and characterization of obstructive coronary plaques in comparison with intravascular ultrasound (IVUS). MATERIALS AND METHODS: Thirty-nine patients were selected who underwent both CT coronary angiography (CTCA) and IVUS. For each stenotic site (n = 61), the maximum vessel cross-sectional area, lumen cross-sectional area, plaque area, and percentage of luminal obstruction were measured. Plaque composition was analyzed according to IVUS (plaque echogenicity and classified into several types: calcified, mixed, fibrous, and soft plaques) and CTCA criteria (Hounsfield units [HU]). The correlation between CTCA and IVUS measurements was determined using Pearson correlation coefficient. The statistical significance of differences in the CT densities of plaques among plaque types determined by IVUS was assessed using the Scheffe method. RESULTS: The correlation coefficients for the measurements of the lumen, vessel, plaque area, and percentage of luminal obstruction were r = 0.712, r = 0.654, r = 0.753, and r = 0.799, respectively. The mean CT density values for soft (n = 10), fibrous (n = 11), mixed (n = 31), and calcified plaques (n = 9) were 54 +/- 13 HU, 82 +/- 17 HU, 162 +/- 57 HU, and 392 +/- 155 HU, respectively. Computed tomography density measurements were not significantly different between soft and fibrous plaques (P = 0.224). CONCLUSIONS: Sixty-four-slice CTCA is a noninvasive modality that allows quantification of coronary artery plaques. However, reliable classification of noncalcified plaques as vulnerable or stable plaques based on CT density measurements is currently limited.

Left atrial appendage thrombi in stroke patients: detection with two-phase cardiac CT angiography versus transesophageal echocardiography.

PURPOSE: To assess the diagnostic accuracy of two-phase 64-section cardiac computed tomographic (CT) angiography for detection of left atrial appendage (LAA) thrombi and differentiation between thrombus and circulatory stasis in patients with stroke, with transesophageal echocardiography (TEE) as the reference standard. MATERIALS AND METHODS: This study was institutional review board approved, and all patients gave written informed consent. Fifty-five consecutive patients (36 men, 19 women; mean age, 61 years) who had recently experienced a stroke, had high-risk factors for thrombus formation, and underwent both two-phase 64-section cardiac CT angiography and TEE up to 5 days apart were examined. Agreement between CT and TEE for detection of thrombus was assessed with kappa statistics. For quantitative analysis, the LAA-ascending aorta attenuation ratio (LAA/AA, in Hounsfield units) was measured on early- and late-phase CT images. The significance of differences in CT attenuation measurements were assessed by using the Student t test. RESULTS: A total of 14 thrombi were detected in the 55 patients at TEE. With TEE as the reference standard, the overall sensitivity, specificity, and positive and negative predictive values of cardiac CT angiography for the detection of thrombus in the LAA were 100% (14 of 14 patients), 98% (40 of 41 patients), 93% (14 of 15 patients), and 100% (40 of 40 patients), respectively. Concordance between cardiac CT angiography and TEE for the detection of thrombus in the LAA was high (overall kappa = 0.953). Mean LAA/AA values were significantly different between thrombus (0.29 HU +/- 0.12 [standard deviation]) and circulatory stasis (0.85 HU +/- 0.12) on late-phase CT images (P < .001). CONCLUSION: Two-phase 64-section cardiac CT angiography is a noninvasive sensitive modality for detecting LAA thrombi and differentiating thrombus from circulatory stasis in stroke patients.

Cardiac computed tomographic angiography for detection of cardiac sources of embolism in stroke patients.

BACKGROUND AND PURPOSE: We assessed the diagnostic performance of 2-phase 64-slice cardiac computed tomographic angiography (CCTA) for the detection of a cardiac source of embolism in stroke patients using transesophageal echocardiography (TEE) as the reference standard. METHODS: We selected 137 patients who had experienced a recent episode of stroke and had undergone both 2-phase 64-slice CCTA and TEE within a period of 5 days. A potential cardiac source of embolism detected at both CCTA and TEE was recorded, and echocardiographic findings were categorized into high- and medium-risk sources based on the TOAST (Trial of Org 10172 in Acute Stroke Treatment) classification. RESULTS: Of 137 patients, 100 abnormal findings in 91 patients were found on TEE, and 46 patients had no abnormal finding on TEE. The overall sensitivity, specificity, positive predictive value, and negative predictive value of the 64-slice CCTA for detecting cardiac sources of embolism were 89% (95% CI, 82%, 95%), 100% (95% CI, 90%, 100%), 100% (95% CI, 95%, 100%), and 81% (95% CI, 70%, 92%), respectively. TEE detected a total of 47 high-risk sources of embolism, whereas CT detected 44 lesions. For medium-risk sources of cardiac embolic stroke, TEE detected a total of 53 abnormal findings, whereas CT detected 44 abnormal findings. Of 53 lesions, there were 8 false-negative results on CT (5 patent foramen ovale and 3 atrial septal aneurysm). CONCLUSIONS: Two-phase 64-slice CCTA is a noninvasive and useful modality for detecting high-risk cardiac sources of embolism in stroke patients.