Impact of Abnormal Remote Stress Myocardial Blood Flow by Dynamic CT Perfusion on Clinical Outcomes.

The objective of this study was to investigate the incremental prognostic value for adverse events of myocardial blood flow (MBF) derived from stress computed tomography perfusion (CTP) at remote myocardium over cardiac risk factors and ischemia. We prospectively analyzed 242 patients who underwent dynamic CTP and CT angiography. Adverse events were defined as a composite of all-cause mortality, non-fatal myocardial infarction, unstable angina, heart failure requiring hospitalization, peripheral artery disease, and stroke. MBF value was calculated in each myocardial segment and ischemia was defined as mild decrease in MBF in two consecutive segments or moderate decrease in a single segment accompanied with a coronary stenosis ≥50%. The mean MBF of the non-ischemic segments was defined as remote MBF. We divided the patients into two groups by median MBF value of 1.15 ml/min/g. During a median follow-up of 18 months, 18 patients had adverse events. Annual event rate showed a significant difference between patients with low (≤1.15 ml/min/g) and high (>1.15 ml/min/g) MBF (6.1% vs 1.8%, p = 0.02). Univariate analysis showed that low MBF was a significant predictor of events (hazard ratio (HR): 3.4; 95% confidence interval (CI): 1.2 to 12.0; p = 0.02). This relationship maintained significant after adjusted for the presence of ischemia and cardiac risk factors (HR: 3.0; 95%CI: 1.1 to 11.1; p = 0.04). In conclusion, MBF value ≤1.15 ml/min/g derived from dynamic CTP in remote myocardium is significantly related with poor outcome and this relationship was independent of myocardial ischemia and cardiac risk factors.

Double region of interest timing bolus technique following endovascular aortic repair: Short-term prognosis analysis.

OBJECTIVES: To compare the incidence rate of reintervention in patients with and without complication findings at aortic computed tomography using double region of interest timing bolus (DRTB) method after endovascular stent placement of the aorta. METHODS: We included 40 patients who underwent computed tomography of the aorta using DRTB method after endovascular stent placement. DRTB method allows to scan the aorta with a short injection time of 9 s by synchronizing the scan speed to the aortic flow. Complication findings at computed tomography were defined as endoleak, rupture, occlusion, and infection. The primary endpoint was reintervention, which was defined as any of the following three events: conversion to open repair, graft revision, or secondary intervention. RESULTS: The mean contrast medium during computed tomography angiography was 38.6 ± 3.9 mL. Complication findings at computed tomography were present in 10 patients (25%): endoleak (n = 9) and infection (n = 1). During a median follow-up of 7 months (interquartile range, 4-11 months), two patients experienced reintervention. Kaplan-Meier curves by complication findings showed that event rate at 6 months was significantly higher in patients with complication findings than in patients without (20% vs 0%, p = 0.01). No patients without complication findings at computed tomography experienced reintervention. CONCLUSIONS: No complication findings at computed tomography after intervention of the aorta resulted in good prognosis in patients who underwent aortic computed tomography using DRTB method.

Aortic CT angiography using the double region of interest timing bolus technique: feasibility of 80 kVp scanning in lean patients.

To investigate the feasibility of aortic computed tomography angiography (CTA) performed at 80 kVp in lean patients using the double region of interest timing bolus (DRTB) technique compared to 100 kVp scanning. This study was approved by the institutional ethics committee, and all patients provided written informed consent. We prospectively included 165 patients from July 2018 to February 2019. We used an 80 kVp protocol when the maximal tube current did not exceed the limit using automatic exposure control; otherwise, 100 kVp was selected. The scan parameters for aortic CTA were determined from the test scan data. Enhancement at six points of the aortoiliac arteries and noise at the bifurcation level were measured. We compared the enhancement and signal to noise ratio (SNR) using Student's t-test. The tube voltage was 80 kVp in 87 patients (53%). The enhancement of the aortoiliac arteries was significantly higher (449.3 ± 77.8 vs 378.7 ± 53.1 HU, p < 0.0001) and the SNR was similar (42.4 ± 11.1 vs 40.0 ± 10.6, p = 0.17), and the amount of contrast medium was lower (33.0 ± 2.5 vs 41.8 ± 3.3 ml, p < 0.001) in the 80 kVp group compared to the 100 kVp group. Reducing the tube current to 80 kVp could decrease the amount of contrast medium used compared to the 100 kVp protocol, while maintaining image quality, for aortic CTA using the DRTB technique.

Double ROI Timing Bolus Technique to Perform Aortic CT Angiography With a 9-Second Contrast Injection Duration.

OBJECTIVE. The purpose of this study was to investigate the feasibility of a double ROI timing bolus technique for performing aortic CT angiography (CTA) with 40 mL of contrast medium over 9 seconds. SUBJECTS AND METHODS. A prospective study from February to July 2018 included 106 patients with clinical indications for evaluation of aortic aneurysm or dissection or suspected aortic disease. Forty-seven of these patients had undergone prior aortic CTA by the conventional method. The scanning speed for the double ROI timing bolus technique was calculated from the time-attenuation curves of the ascending and descending aorta by use of the timing bolus data to synchronize aortic flow. The conventional scan was obtained by injection of 1.7 mL of contrast medium per kilogram of body weight for 25 seconds. Enhancement of six points on the aortoiliac arteries and superior vena cava was measured. The t test was used to compare the values. RESULTS. Use of the double ROI timing bolus method significantly reduced the amount of contrast medium injected compared with the amount for the conventional method (40.0 mL vs 88.0 ± 9.4 mL, p < 0.001). Use of the method significantly increased aortoiliac enhancement (403.3 ± 76.0 HU vs 359.7 ± 61.5 HU, p < 0.001) and significantly decreased enhancement of the superior vena cava (118.9 ± 46.2 HU vs 239.2 ± 130.5 HU, p < 0.001) compared with the conventional method. In the group with prior CTA images available, the effective dose was significantly lower with the double ROI timing bolus than with the conventional method (8.3 ± 1.7 mSv vs 12.4 ± 3.2 mSv, p < 0.01). CONCLUSION. Use of the double ROI timing bolus method can dramatically reduce the amount of contrast medium used during aortic CTA while improving aortic enhancement and reducing radiation dose.

Feasibility of dynamic myocardial CT perfusion using single-source 64-row CT.

BACKGROUND: Dynamic myocardial computed tomography perfusion (CTP) is an emerging technique to diagnose significant coronary stenosis. However, this procedure has not been reported using single-source 64-row CT. OBJECTIVE: To investigate the radiation dose and the diagnostic performance of dynamic CTP to diagnose significant stenosis by catheter exam. METHODS: We prospectively included 165 patients who underwent CTP exam under adenosine stress using a single-source 64-row CT. MBF was calculated using the deconvolution technique. Quantitative perfusion ratio (QPR) was defined as the myocardial blood flow (MBF) of the myocardium with coronary stenosis divided by the MBF of the myocardium without significant stenosis or infarct. Of the 44 patients who underwent subsequent coronary angiography, we assessed the diagnostic performance to diagnose ≥50% stenosis by quantitative coronary analysis (QCA). RESULTS: The average effective dose of dynamic CTP and the entire scans were 2.5 ±â€¯0.7 and 7.3 ±â€¯1.8 mSv, respectively. The MBF of the myocardium without significant stenosis was 1.20 ±â€¯0.32 ml/min/g, which significantly decreased to 0.98 ±â€¯0.24 ml/min/g (p < 0.01) in the area with ≥50% stenosis by CT angiography. The QPR of the myocardium with QCA ≥50% stenosis was significantly lower than 1 (0.84 ±â€¯0.32, 95% confidence interval (CI), 0.77-0.90, p < 0.001). The accuracy to detect QCA ≥50% stenosis was 82% (95%CI, 74-88%) using CT angiography alone and significantly increased to 87% (95%CI, 80-92%, p < 0.05) including QPR. CONCLUSION: Dynamic myocardial CTP could be performed using 64-row CT with a low radiation dose and would improve the diagnostic performance to detect QCA ≥50% stenosis than CT angiography alone.

Data for comparison of computed tomography angiography and dynamic myocardial perfusion to detect significant stenosis by coronary angiography.

This article describes data related to a research article titled "Feasibility of dynamic myocardial CT perfusion using single-source 64-row CT", Tomizawa et al. (in press) [1]. Decrease in the myocardial blood flow could be calculated by performing stress dynamic computed tomography perfusion. This article compares the receiver operating characteristics curve of computed tomography angiography and dynamic myocardial perfusion to diagnose significant stenosis by invasive coronary angiography.

Longer diabetes duration reduces myocardial blood flow in remote myocardium assessed by dynamic myocardial CT perfusion.

AIMS: To investigate the relationship of type 2 diabetes duration and myocardial blood flow (MBF) assessed by myocardial CT perfusion. MATERIALS AND METHODS: We prospectively included 140 patients with type 2 diabetes who underwent dynamic myocardial CT perfusion exam. MBF of the remote myocardium was calculated using the deconvolution technique and the Voronoi method. The relationships of MBF and diabetic duration, diabetic complications, conventional risk factors, coronary calcium, and coronary stenosis were assessed by logistic regression analysis. RESULTS: A weak but significantly negative relationship was present between diabetes duration and MBF (R2 = 0.05, p < 0.01). The average MBF of patients with a duration of >8 years was 13% lower than that of the remaining patients (1.11 ±â€¯0.35 vs 1.28 ±â€¯0.27 ml min-1 g-1, p < 0.01). Duration of one year was associated with a 6% increased risk for low MBF (<1.18 ml min-1 g-1) (odds ratio 1.06, 95% confidence interval 1.01-1.12, p < 0.05). Calcium score was also a significant factor for low MBF (odds ratio 1.08 (per 100 Agatston units), 95% confidence interval 1.01-1.17, p < 0.05). CONCLUSION: Longer diabetes duration is associated with lower MBF independent of conventional cardiac risk factors or the presence of coronary stenosis.

Simplified Bernoulli formula to predict flow limiting stenosis at coronary computed tomography angiography.

OBJECTIVE: To compare the diagnostic performance of estimated energy loss (EEL) with diameter stenosis (DS) to estimate significant stenosis by fractional flow reserve (FFR). MATERIALS AND METHODS: One hundred twenty-five patients were included. EEL was calculated using DS, lesion length, minimal lumen area and left ventricular volume. FFR ≤ 0.80 was determined significant. RESULTS: EEL improved the accuracy from 63% (95% confidence interval (CI): 55-72%) to 83% (95% CI: 75-89%, p < 0.0001). EEL increased the area under the receiver operating characteristics curve from 0.63 to 0.85 (p < 0.0001). CONCLUSIONS: EEL improved the diagnostic performance to detect functionally significant stenosis than DS.

High-risk Plaque and Calcification Detected by Coronary CT Angiography to Predict Future Cardiovascular Events After Percutaneous Coronary Intervention.

RATIONALE AND OBJECTIVES: The purpose of this study was to investigate whether high-risk plaque (HRP) and calcium assessed by coronary computed tomography (CT) could predict future cardiovascular events after second-generation drug-eluting stent (DES) placement. MATERIALS AND METHODS: We analyzed 317 patients from December 2012 to April 2015 who underwent coronary CT followed by DES placement. HRP was defined as a plaque with positive remodeling and low attenuation or a plaque with a napkin-ring sign. Coronary calcium was assessed by Agatston score (AS). Patients were divided into three groups: low risk, HRP negative and AS <400; intermediate risk, HRP positive and AS ≥400; high risk, HRP positive and AS ≥400. The primary end point was a composite of all-cause mortality, myocardial infarction, fatal arrhythmia, or repeated revascularization. Kaplan-Meier analysis was used to estimate the distribution of time to events. RESULTS: A total of 74 events (23%) occurred during a median follow-up of 25.8 months. Patients with primary end points had HRP more frequently (70% vs 51%, P = 0.003) and were more calcified (AS, 471 [interquartile range, 143-1614] vs 289 [interquartile range, 63-787]; P = 0.01) than patients without primary end points. The frequency of primary end point increased significantly in the intermediate- and high-risk patients (P = 0.0011). Multivariate analysis showed that the hazard ratio of the intermediate- and high-risk groups was 1.91 (95% confidence interval, 1.04-3.77; P = 0.037) and 2.66 (95% confidence interval, 1.27-5.73; P = 0.009), respectively. CONCLUSION: Plaque and calcification analysis by coronary CT could predict future cardiovascular events after second-generation DES placement.

Accuracy of computed tomography angiography to identify thin-cap fibroatheroma detected by optical coherence tomography.

BACKGROUND: Thin-cap fibroatheroma (TCFA) is assumed to cause acute coronary syndromes. OBJECTIVE: To compare the accuracy of different models for diagnosing TCFA using parameters derived by CT, validated against optical coherence tomography (OCT). METHODS: One hundred twenty-nine plaques in 106 patients were analyzed using data acquired by 64-row CT with a reconstruction thickness of 0.67 mm and an increment of 0.33 mm. TCFA was defined by OCT as a plaque with lipid content in ≥2 quadrants and the thinnest part of the fibrous cap measuring ≤65 µm. The following parameters were obtained from CT: remodeling index (RI), proportion of low-attenuation (LA) volume (<60 HU), minimum CT number and napkin-ring sign (NRS). We compared three models to predict TCFA: Model 1, RI > 1.1, minimum CT number <30 HU and NRS; Model 2, RI > 1.1, minimum CT number <30 HU or NRS; Model 3, regression model using RI, proportion of LA volume and NRS. RESULTS: In OCT, 83 plaques fulfilled the criteria of TCFA. The area under the receiver operating characteristics curve significantly (p < 0.01) increased to 0.96 (95% confidence interval (CI), 0.92-1.0) in model 3 as compared to models 1 (0.74, 95% CI, 0.68-0.80) and 2 (0.72, 95% CI, 0.67-0.79). Diagnostic accuracy of model 3 (93%) was significantly higher than that of models 1 (67%, p < 0.001) and 2 (80%, p = 0.001). Sensitivity and specificity of model 3 was 94% and 91%, respectively. CONCLUSION: Diagnostic performance to identify TCFA by coronary CTA improves when RI and proportion of LA volume are used as continuous values rather than dichotomizing these parameters.

A clinical model to identify patients with high-risk plaque by coronary computed tomography angiography.

OBJECTIVES: Current clinical models predict the pre-test probability of obstructive coronary artery disease, but these models do not predict the presence of high-risk plaques. Thus the objective of this study was to propose a model to predict high-risk plaque assessed by coronary computed tomography (CT) angiography. METHODS: This study was a retrospective cross-sectional study. A clinical model was derived from 2392 patients and verified by 733 patients who underwent coronary CT suspected of coronary artery disease. High-risk plaque was defined as a plaque with positive remodeling (remodeling index>1.1), low attenuation (<30Hounsfield units) and napkin-ring sign. The risk score was calculated from the following 6 variables with a maximum of 24 points: age, sex, hemoglobin A1c, systolic blood pressure, high-density lipoprotein and smoking status. RESULTS: The proportion of patients with high-risk plaque was 11% and 17% in the derivation and validation cohort, respectively. The area under the receiver operation characteristic curve was 0.71 (95% confidence interval (CI): 0.68 to 0.74) in the derivation cohort and 0.75 (95% CI: 0.70 to 0.79) in the validation cohort. The frequency of high-risk plaques was 4% in the low-risk group (≤8 points) while it was 53% in the high-risk group (≥17 points) of the derivation cohort. CONCLUSIONS: We propose a scoring system to detect high-risk plaque assessed by coronary CT. Patients in the high-risk group have a high prevalence of high-risk plaque and might benefit from lipid lowering therapy.

Relationship of hepatic steatosis severity and coronary artery disease characteristics assessed by coronary CT angiography.

The objective of this study was to investigate the relationship between the severity of hepatic steatosis and coronary artery disease characteristics assessed by coronary computed tomography (CT) angiography. This retrospective analysis consisted of 2028 patients. Hepatic steatosis was evaluated by liver attenuation on unenhanced CT and the patients were divided into four groups (≥60 HU, 54-59 HU, 43-53 HU, ≤42 HU). Coronary calcification was calculated using the Agatston method. Obstructive disease was defined as ≥50 % stenosis assessed by CT. A high-risk plaque was defined by a remodeling index >1.1 and low attenuation (<30 HU). Patients with a segment involvement score >4 were determined to have extensive disease. Logistic regression analysis was performed to study multivariate associations. Severity of hepatic steatosis was associated with coronary calcification (p = 0.02), obstructive disease (p < 0.0001), presence of a high-risk plaque (p = 0.0001) and extensive disease (p = 0.001) in the univariate analysis. However, the relationships were attenuated in the multivariate analysis with the exception of obstructive disease (p = 0.04). Liver attenuation of <54 HU was significantly associated with obstructive coronary artery disease independent of conventional risk factors such as age, sex, diabetes mellitus, hypertension, dyslipidemia and smoking (hepatic attenuation 43-53 HU, odds ratio 1.52, 95 % confidence interval 1.11-2.10, p = 0.01; ≤42 HU, odds ratio 1.65, 95 % confidence interval 1.10-2.45, p = 0.02). Although conventional risk factors were stronger predictors of coronary calcification and plaque formation, the severity of hepatic steatosis remained an independent risk factor for obstructive coronary artery disease. Coronary CT angiography may play a potential role in risk stratification for patients with hepatic steatosis.

The association of hemoglobin A1c and high risk plaque and plaque extent assessed by coronary computed tomography angiography.

The objective of this study was to investigate the relationship of Hemoglobin A1c (HbA1c) and plaque characteristics including high risk plaque and plaque extent. We retrospectively examined 1079 consecutive coronary computed tomography (CT) angiography scans and the HbA1c results. We divided the patients into four groups by the HbA1c status: non-diabetic, ≤6.0; borderline, 6.1-6.4; diabetic low, 6.5-7.1; diabetic high, >7.1. We determined segment involvement score >4 as extensive disease. High risk plaque was defined as two feature positive (FP) plaque which consists of positive remodeling (remodeling index >1.1) and low attenuation (<30 HU). Univariate and multivariate analysis including conventional cardiovascular risk factors, symptoms and medication was performed. Univariate analysis showed that diabetic patients as well as borderline patients were significantly related with 2FP plaque and extensive disease. Although the relationship of borderline patients and 2FP plaque was marginal in multivariate analysis [odds ratio (OR) 1.53, 95% confidence interval (CI) 0.95-2.40, p = 0.07], the elevation of HbA1c was strongly associated with 2FP plaque (diabetic low, OR 2.19, 95% CI 1.37-3.45, p < 0.005; diabetic high, OR 4.14, 95% CI 2.57-6.67, p < 0.0005). The association of HbA1c elevation and extensive disease was quite similar between borderline and diabetic patients (borderline, OR 1.96, 95% CI 1.29-2.95, p < 0.005; diabetic low, OR 1.94, 95% CI 1.25-3.01, p < 0.005; diabetic high, OR 2.19, 95% CI 1.39-3.43, p < 0.005). Patients with elevated HbA1c of >6.0 are potentially at risk for future cardiovascular events due to increased high risk plaque and extensive disease, even below the diabetic level of 6.5. Coronary CT could be used for risk stratification of these patients.

Difference of coronary artery disease severity, extent and plaque characteristics between patients with hypertension, diabetes mellitus or dyslipidemia.

The purpose of this study was to investigate the difference of coronary artery disease (CAD) severity and extent as well as plaque characteristics between patients with either one of hypertension (HT), diabetes mellitus (DM) or dyslipidemia (DL). We retrospectively reviewed the records of 1,161 patients (HT 442, DM 77, DL 248, no disease 394) who underwent coronary computed tomography angiography. Stenosis severity was classified as normal, non-obstructive (1-49 % stenosis), moderate (50-69 % stenosis) or severe (≥70 % stenosis). Segment involvement score (SIS) and segment severity score (SSS) was calculated. We defined patients at risk as patients with obstructive CAD or non-obstructive CAD with extensive disease (SIS ≥ 5). Plaque characteristics were evaluated including positive remodeling, low attenuation and spotty calcification. Obstructive CAD was most frequent in DM patients, followed by HT and DL patients (34, 19 and 15 %, respectively, p < 0.0001). DM patients had more extensive disease than HT and DL patients (SIS 3.1 vs 2.1 vs 1.4, SSS 4.0 vs 2.7 vs 2.0). DM patients were more at risk than HT and DL patients (p < 0.05). The prevalence of positive remodeling, low attenuation and spotty calcium were all highest in DM patients (p < 0.005, vs HT and DL), while low attenuation was more frequent in DL than HT patients (p < 0.005). The median calcium score of HT and DM patients were higher than DL patients (p < 0.01 and p < 0.005, respectively), while no significant difference was observed between HT and DM patients. In conclusion, DM patients possessed more high risk plaque and obstructive as well as extensive CAD compared with HT and DL patients. Coronary calcification was similarly high in HT and DM patients. Low attenuation plaque was more frequent in DL than HT patients.

Phase I/II multicenter study of transarterial chemoembolization with a cisplatin fine powder and porous gelatin particles for unresectable hepatocellular carcinoma: Japan Interventional Radiology in Oncology Study Group Study 0401.

PURPOSE: A multicenter phase I/II study of transarterial chemoembolization with a fine cisplatin powder and gelatin particles (GPs) for multifocal hepatocellular carcinoma (HCC) was conducted. Primary endpoints were dose-limiting toxicity (DLT) and recommended dose (RD). Secondary endpoints were the incidence and severity of adverse events and tumor response. MATERIALS AND METHODS: Nonselective transarterial chemoembolization was performed until all tumor enhancement disappeared. Lipiodol was not used. In the phase I study, the cisplatin dose was escalated from 35 mg/m(2) to 65 mg/m(2) in 15-mg/m(2) increments to determine DLT and RD. In the phase II study, 40 patients were treated with the RD. Toxicity was assessed by Common Toxicity Criteria for Adverse Effects (version 3.0), and tumor response was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST; version 1.0) and European Association for the Study of the Liver (EASL) criteria. RESULTS: A total of 46 patients were enrolled. As no DLT occurred at any dose level in the phase I study, RD was determined as 65 mg/m(2). In the phase II study, the treatment was discontinued in one patient as a result of vasovagal response. Toxicities of grade 3 or higher included nausea (2.2%), pancreatitis (2.2%), cholecystitis (2.2%), thrombocytopenia (8.7%), hyperbilirubinemia (2.2%), and increased aspartate aminotransferase (28.3%) and alanine aminotransferase (21.7%) levels. Tumor response rates under RD were 25.6% and 64.1% by RECIST and EASL criteria, respectively. CONCLUSIONS: Nonselective transarterial chemoembolization with fine cisplatin powder and GPs was well tolerated and effective in patients with multifocal HCC at the RD of 65 mg/m(2).

Pulmonary venous invasion, determined by chest computed tomographic scan, as a potential early indicator of zygomycosis infection: a case series.

Zygomycosis is a life-threatening fungal infection, and its successful treatment requires early diagnosis. To establish radiologic and clinical criteria for early diagnosis, we reviewed 3 post-mortem cases with zygomycosis secondary to hematological diseases. In all cases, an irregular dilatation of pulmonary veins on computed tomography suggested venous invasion by fungal hyphae, which was confirmed at autopsy. In addition, serum samples tested negative for the Aspergillus galactomannan antigen in all cases. These distinguishing radiologic and clinical features may contribute to an earlier diagnosis; more radical treatments, such as amphotericin-B or pulmonary resection; and a more successful outcome for patients with zygomycosis.

Preoperative localization of small peripheral pulmonary nodules by percutaneous marking under computed tomography guidance.

The outcome of computed tomography (CT)-guided percutaneous marking for the preoperative localization of small peripheral pulmonary nodules was analyzed retrospectively. This procedure, in which 21-gauge markers were placed near nodules under local anesthesia on the day of surgery, concerned the patients who received video-assisted thoracoscopic surgery as a primary operative technique. The study included all the 57 patients who underwent CT-guided percutaneous marking before pulmonary resection. The mean nodule size was 1.1 cm. Pneumothorax and pulmonary bleeding were observed in 28 and 17 patients, respectively. Other complications included pain (four), subcutaneous bleeding (two) and dislodgment of the marker (one). Wedge resection during thoracotomy was necessary in seven patients because of severe adhesions (four), multiple wedge resections (one), dislodgment of the marker (one) and difficulty in identifying a nodule (one). Pathological studies revealed 24 metastatic lung tumors, 19 bronchioloalveolar carcinomas (BACs), five adenocarcinomas with mixed subtypes, three granulomas, two atypical adenomatous hyperplasias and six miscellaneous others. Wedge resection for malignancy was performed in 39 patients with 41 lesions. The median follow-up period was 46 months. A positive surgical margin and recurrence at the surgical stump were observed in one case each. In conclusion, preoperative CT-guided marking was safe and effective, although marker dislodgment, positive surgical margin and recurrence at the surgical stump were observed infrequently.

Adaptive statistical iterative reconstruction for volume-rendered computed tomography portovenography: improvement of image quality.

PURPOSE: Adaptive statistical iterative reconstruction (ASIR) is a reconstruction technique for computed tomography (CT) that reduces image noise. The purpose of our study was to investigate whether ASIR improves the quality of volume-rendered (VR) CT portovenography. MATERIALS AND METHODS: Institutional review board approval, with waived consent, was obtained. A total of 19 patients (12 men, 7 women; mean age 69.0 years; range 25-82 years) suspected of having liver lesions underwent three-phase enhanced CT. VR image sets were prepared with both the conventional method and ASIR. The required time to make VR images was recorded. Two radiologists performed independent qualitative evaluations of the image sets. The Wilcoxon signed-rank test was used for statistical analysis. Contrast-noise ratios (CNRs) of the portal and hepatic vein were also evaluated. RESULTS: Overall image quality was significantly improved by ASIR (P < 0.0001 and P = 0.0155 for each radiologist). ASIR enhanced CNRs of the portal and hepatic vein significantly (P < 0.0001). The time required to create VR images was significantly shorter with ASIR (84.7 vs. 117.1 s; P = 0.014). CONCLUSION: ASIR enhances CNRs and improves image quality in VR CT portovenography. It also shortens the time required to create liver VR CT portovenographs.

Endometrial stromal sarcoma located in the myometrium with a low-intensity rim on T2-weighted images: report of three cases and literature review.

Endometrial stromal sarcoma (ESS) most commonly grows from the uterine endometrium into the endometrial cavity; it is rarely located in the myometrium alone, where it may resemble degenerated leiomyoma on magnetic resonance imaging (MRI). We present three cases of intramyometrial ESS mimicking degenerated leiomyoma, all of which have a characteristic low-intensity rim on T2-weighted images. Histopathological examination revealed the rim to consist of fibrous tissue layers and/or a decrease in free water caused by distortion of myometrial tissue following tumor expansion. ESS should be included in the differential diagnosis of intramyometrial mass with low-intensity rim on T2-weighted image, especially if the mass shows degeneration with no or mild intratumoral hemorrhage.