Ji Eun Nam

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.

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.

Cardioembolic Stroke: Dual-Energy Cardiac CT for Differentiation of Left Atrial Appendage Thrombus and Circulatory Stasis

PURPOSE To assess the diagnostic performance of dual-energy cardiac computed tomography (CT) in the detection of left atrial appendage (LAA) thrombi and differentiation between thrombus and circulatory stasis in patients with stroke, by using transesophageal echocardiography (TEE) as the reference standard. MATERIALS AND METHODS The institutional review board approved this study, and patients provided informed consent. Thirty-two patients with stroke who had atrial fibrillation (AF) and either thrombus or the spontaneous echo contrast (SEC) echo pattern at TEE were prospectively enrolled. For the control group, 31 patients who were planning to undergo AF ablation and who had no abnormalities at TEE were enrolled. All patients underwent dual-energy cardiac CT that was not electrocardiographically gated. For quantitative analysis, iodine concentration was measured on CT images. The statistical significance of differences in mean iodine concentration between thrombus and SEC as measured at CT was assessed by using the Student t test. RESULTS Among the 63 patients, a total of 13 thrombi and 19 instances of SEC were detected at TEE. Using TEE as the reference standard, the overall sensitivity, specificity, positive predictive value, and negative predictive value of dual-energy cardiac CT in the detection of thrombi and SEC in the LAA were 97% (95% confidence interval [CI]: 82%, 100%), 100% (95% CI: 86%, 100%), 100%, and 97%, respectively. At CT, the mean iodine concentration was 1.23 mg/mL ± 0.34 (standard deviation) for thrombus and 3.61 mg/mL ± 1.01 for SEC (P = .001). CONCLUSION Dual-energy cardiac CT is a highly sensitive modality for detecting LAA thrombus and for differentiating thrombus from SEC in patients with stroke.

Thrombus in the Left Atrial Appendage in Stroke Patients: Detection with Cardiac CT Angiography—A Preliminary Report

PURPOSE To assess the diagnostic performance of 64-section cardiac computed tomographic (CT) angiography for detection of left atrial appendage (LAA) thrombi in stroke patients by using transesophageal echocardiography (TEE) as the reference standard. MATERIALS AND METHODS This study was approved by the institutional review board. Records were reviewed from 101 consecutive patients who had experienced a recent stroke (onset within the previous 1 month) from a suspected cardioembolic source and who had undergone both 64-section cardiac CT angiography and TEE within 1 week. The numbers of thrombi in the LAA detected with cardiac CT angiography and with TEE were recorded, and the agreement between thrombus detection with CT and with TEE was assessed by using kappa statistics. RESULTS Eight thrombi in the LAA were detected with TEE, and 12 were detected with cardiac CT angiography. With TEE used as the reference standard, the overall sensitivity, specificity, and accuracy of 64-section cardiac CT angiography for detecting thrombi were 100% (95% confidence interval [CI]): 63%, 100%), 95% (95% CI: 90%, 99%), and 96% (95% CI: 92%, 100%), respectively. The concordance between LAA thrombus detection with 64-section cardiac CT angiography and with TEE was high: 89 patients with no thrombus at CT or TEE; eight patients with thrombus at both CT and TEE; and four patients with thrombus at CT but not at TEE (overall kappa = 0.779 [95% CI: 0.571, 0.987]). CONCLUSION Sixty-four-section cardiac CT angiography is a noninvasive and sensitive modality for detecting thrombi in the LAA of stroke patients. Although TEE is currently considered the reference standard modality for detecting LAA thrombi, 64-section cardiac CT angiography has the potential to become a useful modality for detection of intracardiac thrombus.

Diagnostic Accuracy of CT Fluoroscopy-Guided Needle Aspiration Biopsy of Ground-Glass Opacity Pulmonary Lesions

OBJECTIVE The purpose of this study was to evaluate the diagnostic performance of CT fluoroscopy-guided percutaneous needle aspiration biopsy of ground-glass opacity (GGO) pulmonary lesions. MATERIALS AND METHODS Twenty-eight patients with GGO lesions who underwent CT fluoroscopy-guided needle aspiration biopsy were enrolled in this study. GGO lesions were divided into three groups according to their size: group 1, lesions < or = 10 mm (n = 10); group 2, lesions 11-20 mm (n = 10); and group 3, lesions > 20 mm (n = 8). Sensitivity, specificity, and diagnostic accuracy were calculated on the basis of 28 needle aspiration biopsy results and were compared among the three groups using Fishers exact test. Diagnostic accuracy was also compared according to length of needle path (< 5 cm vs 5-9 cm vs > 9 cm) and GGO component (50-90% vs > 90%). Each case was reviewed for complications, which included pneumothorax, thoracostomy tube insertion, and hemoptysis. RESULTS There were 17 (61%) malignant and 11 (39%) benign lesions. Three (10%) biopsy results were nondiagnostic, all of which were confirmed as benign. The sensitivity, specificity, and accuracy of CT fluoroscopy-guided needle aspiration biopsy for diagnosing GGO were 67%, 100%, and 80% in group 1; 71%, 100%, and 80% in group 2; and 75%, 100%, and 88% in group 3. The diagnostic accuracy of CT fluoroscopy-guided needle aspiration biopsy for diagnosing GGO was not significantly different among the three groups (p > 0.05). The diagnostic accuracy was not significantly different according to the length of the needle path (p > 0.05). However, diagnostic accuracy was significantly more accurate in mixed GGO lesions than in pure GGO lesions (p = 0.046). Five patients (18%) developed a pneumothorax, two of whom (7%) required placement of a thoracostomy tube. Mild hemoptysis occurred in three patients (11%). CONCLUSION CT fluoroscopy-guided needle aspiration biopsy is a useful diagnostic technique for GGO pulmonary lesions and has an acceptable complication rate, even for small and deeply located lesions. The diagnostic accuracy is influenced by the GGO component.

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.

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.

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.

Automatic Tube Potential Selection with Tube Current Modulation (APSCM) in coronary CT angiography: Comparison of image quality and radiation dose with conventional body mass index-based protocol

BACKGROUND The use of Automatic Tube Potential Selection with Tube Current Modulation (APSCM) may lower radiation dose, but it is unknown whether image quality is maintained. OBJECTIVE The aim of this study was to evaluate the radiation dose and image quality of APSCM application compared with conventional body mass index (BMI)-based examination protocol for coronary computed tomography angiography (CTA). METHODS Consecutive patients (n = 487) were retrospectively enrolled: 239 patients who underwent coronary CTA with APSCM (APSCM group) and 248 patients who underwent coronary CTA with a BMI-based tube potential (in kV) and tube current-time product (in mAs) protocol (BMI-based group). Comparison of quantitative and qualitative image quality and radiation dose was performed. RESULTS The use of APSCM found significant reduction in radiation dose compared with the BMI-based protocol, with a significantly more frequent use of 80 kV (P < 0.0001). Diagnostic image quality was maintained, with no significant difference between the 2 groups (P = 0.887). CONCLUSION The use of APSCM for coronary CTA significantly reduced radiation dose while maintaining image quality; therefore, it is feasible in daily practice which covers patients with various BMI values.

Air-trapping zone surrounding sclerosing hemangioma of the lung.

We present two cases of sclerosing hemangioma of the lung with a peculiar radiologic finding: an air-trapping zone surrounding the tumor. On microscopic examinations, the tumor was of the hemangiomatous subtype, and the radiolucent zone corresponded to enlarged alveoli with septal destruction. A possible mechanism in the production of an air-trapping zone around a sclerosing hemangioma is bleeding from the highly vascular tumor followed by expectoration in communication with an airway. We reviewed the literature on the air meniscus sign in sclerosing hemangioma and concluded that although it is not a common finding, it could be of help in the confident diagnosis of sclerosing hemangioma and in differentiating it from other benign tumors of the lung.