Low Tube Voltage Computed Tomography Venography for Patients With Deep Vein Thrombosis of the Lower Extremities　- A Comparison With Venous Ultrasonography.

BACKGROUND: Low tube voltage computed tomography venography (CTV) can be expected to increase imaging contrast and decrease radiation exposure by using iterative reconstruction (IR). This study evaluated the diagnostic ability of low tube voltage CTV with IR for deep vein thrombosis (DVT), compared to ultrasonography (US).Methods and Results:Two experienced radiologists retrospectively reevaluated the CTV data of 55 of 318 consecutive patients suspected of having DVT or pulmonary embolism between December 2015 and April 2017. The 55 patients had undergone both low tube voltage CTV and US (within 1 day before or after CTV). The lower extremity veins were divided into 10 segments. The DVT forms were categorized into 3 types: complete, concentric, and eccentric. We analyzed the 534 overall segments (16 segments excluded in US) measured using both CTV and US. The sensitivity-specificity was overall 73.3-90.0%, for femoropopliteal, it was 90.0-93.2%, and for the calf, it was 71.1-87.2%. The diagnostic accuracy between the 'eccentric only' and 'others' groups focusing on DVT forms was compared, and significant differences were revealed, especially in the muscular vein. CONCLUSIONS: The DVT diagnostic ability above the knee was comparable between low tube voltage CTV with IR and conventional CTV, and the radiation dose was reduced. It was suggested that eccentric DVT measured by CTV tend to be a false-positive, especially in the calf muscular vein.

Quantitative 3D Shape Analysis of CT Images of Thymoma: A Comparison With Histological Types.

OBJECTIVE. The purpose of this study is to differentiate between low- and high-risk types of thymoma using quantitative 3D shape analysis of CT images. MATERIALS AND METHODS. This retrospective study included 44 patients with a pathologic diagnosis of thymoma. Two radiologists semiautomatically contoured CT images of the tumors and evaluated 3D shape parameters-namely, quantitative indicators of surface smoothness, including sphericity, ellipsoidality, and discrete compactness. The visual CT findings that were analyzed included longest diameter, shape (round-oval, lobulated, or irregular), calcification, cystic or necrotic changes, and enhancement pattern (homogeneous or heterogeneous). The difference and discriminating performance between low-risk (types A, AB, and B1) and high-risk (types B2 and B3) thymomas were statistically assessed. Interobserver agreement was determined using the concordance correlation coefficient. RESULTS. Twenty-three low-risk and 21 high-risk thymomas were identified on the basis of pathologic findings. The median values of sphericity and ellipsoidality were significantly higher for low-risk thymomas than for high-risk thymomas (for sphericity, 0.566 vs 0.517; for ellipsoidality, 0.941 vs 0.875; p < 0.05 for both). The AUC values of sphericity and ellipsoidality were 0.704 and 0.712, respectively. The best cutoff values were 0.528 and 0.919 for sphericity and ellipsoidality, respectively. Risk assessment combining these cutoff values and the mode of tumor detection (incidental detection or detection based on the presence of symptoms) improved the AUC value to 0.856 (sensitivity, 81.0% [17 of 21 patients]; specificity, 82.6% [19 of 23 patients]). All 3D shape parameters showed almost perfect interobserver agreement (concordance correlation coefficient, > 0.90). The visual CT findings were not significantly different between low- and high-risk thymomas (p > 0.05 for all). CONCLUSION. Quantitative 3D shape analysis has excellent reproducibility, and combining this technique with information on the detection mode helps differentiate low- from high-risk thymomas.

Japanese Survey of Radiation Dose Associated With Coronary Computed Tomography Angiography　- 2013 Data From a Multicenter Registry in Daily Practice.

BACKGROUND: Although coronary computed tomography angiography (CTA) is frequently used for identifying coronary artery disease, no studies have investigated the radiation dose in detail in Japan. The aim of this study was to estimate the radiation dose of coronary CTA in Japanese clinical practice and to identify the independent predictors associated with radiation dose.Methods and Results:A multicenter, retrospective, observational study (54 institutions) was conducted for estimating the radiation dose of coronary CTA in 2,469 patients between January and December 2013. Independent predictors associated with radiation dose were investigated on linear regression analysis. Median dose-length product (DLP) was 809.0 mGy·cm (IQR, 350.0-1,368.8 mGy·cm), corresponding to an estimated radiation dose of 11 mSv. The DLP per site significantly differed between institutions (median DLP per site, 92-2,131 mGy·cm; P<0.05). Independent predictors associated with radiation dose on multivariable linear regression were body weight, heart rate, non-stable sinus rhythm, scan length, tube voltage setting, electrocardiogram (ECG)-gated scanning protocol, and the image reconstruction technique (P<0.05 each). CONCLUSIONS: The coronary CTA radiation dose was relatively high in 2013, and it varied significantly between institutions. Effective strategies for radiation dose reduction were low tube voltage ≤100 kVp, retrospective ECG-gated scanning with dose modulation technique, prospective ECG-gated scanning, and the iterative reconstruction technique.

Differential diagnosis of uterine smooth muscle tumors using diffusion-weighted imaging: correlations with the apparent diffusion coefficient and cell density.

The purpose of this study is to investigate the utility of the apparent diffusion coefficient (ADC) in differentiating benign and malignant uterine smooth muscle tumors classified by signal intensity (SI) on T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), and to determine the correlation between ADC and tumor cell density. This retrospective study reviewed 168 lesions in 134 cases with pathologically confirmed uterine smooth muscle tumors, including 6 leiomyosarcomas and 3 smooth muscle tumors of uncertain malignant potential, and preoperative magnetic resonance imaging examinations performed between October 2009 and November 2012. T2WI and DWI were also performed for each subject. Tumors were then classified according to SI on T2WI and DWI relative to myometrial SI. The correlation between ADC and tumor cell density was also determined. In Group 1 (high on both T2WI/DWI), mean ADC was significantly lower for leiomyosarcoma (0.91 × 10(-3) mm(2)/s) than for leiomyoma (1.30 × 10(-3) mm(2)/s; p < 0.05) and mean cell density significantly higher for leiomyosarcoma (42.9%) than for leiomyoma (22.4%; p < 0.05). A strong negative correlation was seen between ADC and tumor cell density in Group 1 (Spearman, R = -0.72; p < 0.05). ADC may help to differentiate benign from malignant uterine smooth muscle tumors, particularly tumors with high SI on T2WI and DWI.

Association between pre-treatment computed tomography findings and post-treatment persistent decrease in lung perfusion blood volume.

The purpose of this study was to evaluate pre-treatment CT findings in patients with acute pulmonary embolism (PE) and determine the imaging findings associated with residual hypoperfused segments in post-treatment lung perfused blood volume (LPBV). We evaluated 91 patients with acute PE who underwent dual-energy CT before and after treatment. The location of thrombi (proximal or distal) and patency of the pulmonary artery (occlusive or non-occlusive) were recorded using pre-treatment computed tomography pulmonary angiography (CTPA). Residual hypoperfusion was defined as a perfusion-decreased area seen in both the pre- and post-treatment LPBVs. The association of the location of the thrombus and vascular patency of pre-treatment CTPA with residual hypoperfusion on a segmental and patient basis was examined. In the segment-based analysis, the proportion of residual hypoperfusion in the proximal group was significantly higher than that in the peripheral group (33/125 [26.4%] vs. 9/87 [10.3%], P = 0.004). Patient-based analysis also showed that the proportion of residual hypoperfusion in patients with pre-treatment proximal thrombus was significantly higher than those without (16/42 [38.1%] vs. 3/25 (12.0%); P = 0.022). Pre-treatment vascular patency was not significantly associated with residual hypoperfusion (P > 0.05). Therefore, careful follow-up is necessary, especially in patients with proximal thrombi.

Massive hemoptysis treated with embolization of an ectopic bronchial artery arising from the right thyrocervical trunk: a case report.

BACKGROUND: Ectopic bronchial artery and non-bronchial systemic arteries may be the culprit vessels of hemoptysis. The main cause of clinical failure of bronchial artery embolization is incomplete embolization caused by the misidentification of the culprit arteries by conventional angiography. Multidetector computed tomography angiography is useful for visualizing the culprit arteries. CASE PRESENTATION: An 82-year-old man was admitted with hemoptysis. Preprocedural multidetector computed tomography angiography revealed an ectopic bronchial artery branching from the right thyrocervical trunk. Superselective embolization of the ectopic bronchial artery was performed using gelatin sponge particles and metallic coils. Hemoptysis was controlled by this procedure without any associated complications. CONCLUSIONS: Ectopic bronchial arteries originating from the thyrocervical trunk are rare. Preprocedural multidetector computed tomography angiography is useful for visualizing the culprit arteries of hemoptysis, especially if a patient has an ectopic bronchial artery or an ectopic non-bronchial systemic artery.

U-Net-based image segmentation of the whole heart and four chambers on pediatric X-ray computed tomography.

This study aimed to determine whether a U-Net-based segmentation method could be used to automatically extract regions of the whole heart and atrioventricular regions from pediatric cardiac computed tomography images with high accuracy. Pediatric cardiac contrast computed tomography images with no abnormalities (n = 20; patient age, 0-13 years; mean 5 years) were used for segmentation of the whole heart and each atrioventricular region using U-Net. Segmentation accuracy was evaluated using the Dice similarity coefficient. The mean Dice similarity coefficient for the whole-heart segmentation was high at 0.95. There were no significant differences between age categories. The median Dice similarity coefficients for segmentation of the atria and ventricles were good (> 0.86). There were significant differences between age categories at some sites. Differences in the Dice similarity coefficient may have occurred because the target diseases and examination procedures differed according to subject age. There was no clear tendency for similar values between subjects of school age, close to adulthood, and newborns; good agreement was obtained in all age categories. These results suggest that U-Net-based segmentation may be useful for automatic extraction of the whole heart and atrioventricular regions from pediatric computed tomography images.

Brown adipose tissue dysfunction promotes heart failure via a trimethylamine N-oxide-dependent mechanism.

Low body temperature predicts a poor outcome in patients with heart failure, but the underlying pathological mechanisms and implications are largely unknown. Brown adipose tissue (BAT) was initially characterised as a thermogenic organ, and recent studies have suggested it plays a crucial role in maintaining systemic metabolic health. While these reports suggest a potential link between BAT and heart failure, the potential role of BAT dysfunction in heart failure has not been investigated. Here, we demonstrate that alteration of BAT function contributes to development of heart failure through disorientation in choline metabolism. Thoracic aortic constriction (TAC) or myocardial infarction (MI) reduced the thermogenic capacity of BAT in mice, leading to significant reduction of body temperature with cold exposure. BAT became hypoxic with TAC or MI, and hypoxic stress induced apoptosis of brown adipocytes. Enhancement of BAT function improved thermogenesis and cardiac function in TAC mice. Conversely, systolic function was impaired in a mouse model of genetic BAT dysfunction, in association with a low survival rate after TAC. Metabolomic analysis showed that reduced BAT thermogenesis was associated with elevation of plasma trimethylamine N-oxide (TMAO) levels. Administration of TMAO to mice led to significant reduction of phosphocreatine and ATP levels in cardiac tissue via suppression of mitochondrial complex IV activity. Genetic or pharmacological inhibition of flavin-containing monooxygenase reduced the plasma TMAO level in mice, and improved cardiac dysfunction in animals with left ventricular pressure overload. In patients with dilated cardiomyopathy, body temperature was low along with elevation of plasma choline and TMAO levels. These results suggest that maintenance of BAT homeostasis and reducing TMAO production could be potential next-generation therapies for heart failure.

Computed tomography findings of acute gastric peptic ulcer.

PURPOSE: To report the computed tomography (CT) findings of acute peptic ulcer disease (PUD) and to evaluate the usefulness of contrast media for diagnosis. METHODS: This retrospective study included 51 patients diagnosed with acute gastric peptic ulcer by endoscopy. Using a κ analysis, two radiologists independently reviewed contrast-enhanced emergency CTs performed within 24 h of endoscopy. Evaluation findings included low-attenuation wall thickening, focal wall thickening, focal luminal outpouching, perigastric fat stranding, ascites, adjacent lymphadenopathy, and high-density gastric contents. Of the 51 patients, 48 underwent both non-contrast-enhanced and contrast-enhanced CT, and two radiologists also evaluated the presence or absence of these findings on a non-contrast-enhanced CT. McNemar's test was used to evaluate the contrast media's usefulness. RESULTS: Interobserver variability of perigastric fat stranding revealed substantial agreement between evaluators, and other findings had almost perfect agreement. High-density gastric contents were the most recognized findings (60%). Low-attenuation focal wall thickening and focal luminal outpouching were observed in relatively large numbers (~50%) of the cases on contrast-enhanced CT. The CT examinations using contrast media provided significantly higher detectability of low-attenuation wall thickening and focal luminal outpouching than CT examinations without using contrast media. CONCLUSION: Acute PUD can be suspected in patients with nonspecific abdominal symptoms in whom emergency CT shows high-density gastric contents, focal low-attenuation wall thickening, and/or focal luminal outpouching. Our study showed that contrast media are useful for diagnosis.

Comparison of magnetic resonance imaging with transthoracic echocardiography in the diagnosis of ventricular septal defect-associated coronary cusp prolapse.

PURPOSE: To compare magnetic resonance imaging (MRI) with transthoracic echocardiography (TTE) in the diagnosis of coronary cusp prolapse (CCP) as a complication of ventricular septal defect (VSD). MATERIALS AND METHODS: Twenty-three patients (10 males, 13 females, mean age 9 years) with clinically suspected CCP were included in a retrospective study. Long and short axis cine images and electrocardiogram (ECG)-gated axial T1-weighted image MRI images were evaluated for deformity and protrusion of right and noncoronary cusps. We compared MRI and TTE results. We compared the agreement between MRI and TTE in outlet VSD and membranous VSD. RESULTS: On MRI, 19 patients had right coronary cusp prolapse (RCCP), three had noncoronary cusp prolapse (NCCP), and one patient had RCCP and NCCP on MRI. Twenty-two patients had RCCP on TTE and none had NCCP. Seventeen patients had outlet defects and six patients had a membranous defect at operation. All patients with an outlet VSD had RCCP on both MRI and TTE. The agreement between MRI and TTE in outlet VSD was better than in membranous VSD. CONCLUSION: MRI results corresponded with TTE results in patients with outlet VSDs, but discordant results were observed in patients with membranous VSDs.

Characteristics and CT features of subcarinal air collections/main bronchial diverticula.

The aim of this study was to evaluate the characteristics and CT features of subcarinal air collections on thin-section multidetector-row computed tomography (MDCT). Two hundred asymptomatic adult subjects without a history of pulmonary disease underwent MDCT. The CT appearances and characteristics of foci of extraluminal air contiguous to the main bronchus in the subcarinal region were retrospectively analysed. Subcarinal air collections were found in 81 of 200 subjects (41%) and were spotty or microtubular in 67 of 81 subjects and rounded or oval in the other 14. Each subcarinal air focus communicated, or seemed to communicate, with the adjacent bronchus in 76 of 81 cases. Our data demonstrate that extraluminal air foci in the subcarinal region are common CT findings and routinely depicted on thin-section MDCT, and that most of these lesions seem to be main bronchial diverticula. Cystic air foci in the subcarinal region should be called subcarinal air cysts. The precise recognition of these cysts improves the ability to avoid misidentification, such as pneumomediastinum.

A novel program to accurately quantify infarction volume by (99m)Tc MIBI SPECT, and its application for re-analyzing the effect of erythropoietin administration in patients with acute myocardial infarction.

BACKGROUND: This study aimed to apply a software to calculate myocardial infarction (MI) volume by single-photon emission computed tomography. METHODS AND RESULTS: The cardioVol software has been developed to reconstruct 3D figures from sequential short axis images. We re-analyzed the data from the EPO/AMI-I Study. The MI volume at baseline correlated with maximum creatine kinase. The MI volume significantly decreased during the 6-month follow up in the erythropoietin (EPO) group, but not in the control group. The decrements of MI volume in the EPO group were significantly larger than those in the control group. CONCLUSIONS: The efficacy of EPO was further confirmed by the software.

Single-dose intravenous administration of recombinant human erythropoietin is a promising treatment for patients with acute myocardial infarction - randomized controlled pilot trial of EPO/AMI-1 study -.

BACKGROUND: Erythropoietin (EPO) has been found to have anti-apoptotic and tissue protective effects on the myocardium. The aim of the present pilot study was to observe the safety and efficacy of EPO administration for patients with acute myocardial infarction (AMI). METHODS AND RESULTS: Patients admitted with AMI had all undergone successful percutaneous coronary intervention (PCI). Patients were randomly assigned to 2 groups (control and EPO groups), and given 12,000 IU EPO iv or saline after PCI. The primary endpoints were the difference between the acute phase and chronic phase (6 months after the attack) regarding left ventricular function as measured on electrocardiogram-gated single-photon emission computed tomography. Thirty-six patients (control 16, EPO 20) were eligible for analysis. Left ventricular ejection fraction (LVEF) significantly increased in the EPO group (from 51.0+/-19.6% to 58.5+/-15.0%, P=0.0238), but not in the control group. Further analysis was separately undertaken in patients with occlusion in the left anterior descending artery (LAD) and others (non-LAD). LVEF was <50% in most patients in the LAD subgroup, and LVEF significantly increased in the EPO group (37.5+/-13.0 to 52.7+/-15.8, P=0.0049), but not in the control group. EPO administration did not trigger any adverse clinical events. CONCLUSIONS: EPO administration is a promising treatment for AMI.

Screening and follow-up of chronic liver diseases with understanding their etiology in clinics and hospitals.

BACKGROUND AND AIM: Considering the increasing prevalence of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis (NASH), the development of an effective screening and follow-up system that enables the recognition of etiological changes by primary physicians in clinics and specialists in hospitals is required. METHODS: Chronic hepatitis B (HBV) and C (HCV), NASH, and alcoholic steatohepatitis (ASH) patients who were assayed for Mac-2-binding protein glycosylation isomer (M2BPGi) (n = 272) and underwent magnetic resonance elastography (MRE) (n = 119) were enrolled. Patients who underwent MRE were also tested by ultrasound elastography (USE) (n = 80) and for M2BPGi (n = 97), autotaxin (ATX) (n = 62), and platelet count (n = 119), and their fibrosis-4 (FIB-4) index was calculated (n = 119). RESULTS: FIB-4 index >2, excluding HBV-infected patients, M2BPGi >0.5, ATX >0.5, and platelet count <20 × 104/µL were the benchmark indices, and we took into consideration other risk factors, such as diabetes mellitus and age, to recommend further examinations, such as USE, based on the local situation to avoid overlooking hepatocellular carcinoma (HCC) in the clinic. During specialty care in the hospital, MRE exhibited high diagnostic ability for fibrosis stages >F3 or F4; it could efficiently predict collateral circulation with high sensitivity, which can replace USE. We also identified etiological features and found that collateral circulation in NASH/ASH patients tended to exceed high-risk levels; moreover, these patients exhibited more variation in HCC-associated liver stiffness than the HBV and HCV patients. CONCLUSIONS: Using appropriate markers and tools, we can establish a stepwise, practical, noninvasive, and etiology-based screening and follow-up system in primary and specialty care.

Detectability of the choroid plexus of the third ventricle with magnetic resonance ventriculography.

PURPOSE: To clarify the detectability of the choroid plexus of the third ventricle (ChPl3V) with magnetic resonance ventriculography (MRVn) employing a steady-state free precession (SSFP) sequence in comparison to surgical endoscopic movies as a golden standard, as we encountered some clinical cases of total agenesis of corpus callosum (ACC) where we could not recognize the choroid plexus of the third ventricle and found no previous article addressing this problem. MATERIALS AND METHODS: This retrospective study included consecutive patients from 2010 to 2016 for whom endoscopic evaluation of the third ventricle was conducted. The anterior portion of the right and left streaks of ChPl3V was evaluated in 8 patients on 16 sites, while the posterior portion of both streaks of ChPl3V was evaluated in 13 patients on 26 sites. Sensitivity of MRVn to visualize ChPl3V with endoscopic movies as the golden standard was calculated. RESULTS: Sensitivity of MRVn in visualizing the anterior portion of ChPl3V was 0.813, and that for the posterior portion 0.692. The anterior portion of ChPl3V was visualized in all cases where no tumor contacted the foramen of Monro. CONCLUSION: MRVn visualizes the anterior portion of ChPl3V with significant sensitivity and the posterior portion with lower one.

Assessment of a simple method of heart weight estimation by postmortem computed tomography.

BACKGROUND: Measurement of heart weight is important when investigating cause of death, but there is presently no satisfactory method of heart weight estimation by postmortem computed tomography (PMCT). METHOD: We investigated 33 consecutive cases that underwent both PMCT and autopsy between February 2008 and June 2014. Heart and left ventricular (LV) weights were calculated by PMCT morphometry. We used a simple method to estimate LV weight: We assumed that LV was an ellipsoid and multiplied its volume on PMCT with myocardial specific gravity. We then compared the various heart and LV weights using linear regression. The calculated and estimated LV weights on PMCT were also compared. RESULTS: It was not possible to predict heart weight at autopsy from PMCT (R2 = 0.53). However, heart weight at autopsy could be accurately predicted from LV weight calculated by PMCT (R2 = 0.77). In addition, there was a strong correlation between the estimated and calculated LV weights by PMCT (R2 = 0.92). Heart weight at autopsy could also be accurately predicted using the PMCT-estimated LV weight (R2 = 0.72). CONCLUSION: Heart weight at autopsy could be accurately predicted using a simple method in which LV volume was assumed to be an ellipsoid on PMCT.

Measuring noncalcified coronary atherosclerotic plaque using voxel analysis with MDCT angiography: a pilot clinical study.

OBJECTIVE: The purpose of our study was to evaluate a new method using voxel analysis for quantifying noncalcified plaque in coronary arteries using MDCT angiography (MDCTA) compared with luminal stenosis by catheter coronary arteriography. MATERIALS AND METHODS: Forty-one normal and eight abnormal arterial cross sections with noncalcified plaque selected from 40 patients undergoing MDCTA were analyzed for percentage of stenosis and plaque volume using a voxel analysis technique. RESULTS: Using voxel analysis, the normal arterial wall thickness was determined to be 0.8 +/- 0.4 mm. Attenuation values (in Hounsfield units) for normal segments ranged between 30 and 175 H and for abnormal (plaque-containing) segments ranged from -49 to 139 H (p < 0.05). Plaque volume measurements varied from 0.90 to 156 mm(3) with good interobserver correlation (R(2) = 0.9671). Percentage of stenosis correlated with quantitative coronary arteriography measurement (R(2) = 0.55). Voxel analysis underestimated the percentage of stenosis (Pearson's correlation coefficient, 1.2; p = 0.03). CONCLUSION: The study shows that the voxel analysis technique appears to be an accurate and reproducible method to measure arterial wall thickness, noncalcified plaque, and degree of arterial stenosis using density values measured in Hounsfield units. The technique may be useful on further correlative studies.

Measuring noncalcified coronary atherosclerotic plaque using voxel analysis with MDCT angiography: phantom validation.

OBJECTIVE: This purpose of this study was to evaluate the accuracy and reproducibility of a voxel analysis technique for measuring noncalcified plaque in the coronary arteries. MATERIALS AND METHODS: Polyethylene phantoms representing noncalcified plaque were scanned in both MDCT and micro-CT scanners and inter- and intrareader variability of volume calculation was performed. RESULTS: Volume measurements by both MDCT and micro-CT were comparable to the true volume as measured by micrometry (< 3%, p = 0.05). CONCLUSION: There appears to be no significant difference (< 3%) between MDCT and micro-CT measurements.

Diagnostic limitations of 10 mm thickness single-slice computed tomography for patients with suspected appendicitis.

PURPOSE: The aim of this retrospective analysis was to evaluate the accuracy of 10 mm thickness single helical computed tomography (CT) examination for confirming the diagnosis of appendicitis or providing a diagnosis other than appendicitis, including underlying periappendical neoplasms. MATERIALS AND METHODS: From April 1, 2001 to March 30, 2005, a total of 272 patients with suspected appendicitis underwent CT examinations. Of the 272 patients, 106 (39%) underwent surgery. Seven CT examinations for seven patients were excluded because of inconsistency of the CT protocol. We therefore reviewed 99 CT images (99 patients) with correlation to surgical-pathological findings to clarify the diagnostic accuracy of CT examinations. We compared the postoperative diagnosis with the preoperative CT report. The final diagnoses were confirmed by macroscopic findings at surgery and pathological evaluations if necessary. RESULTS: Of the 99 patients, 87 had acute appendicitis at surgery. The sensitivity, specificity, and accuracy of CT were 98.9%, 75.0%, and 96.0%, respectively. The positive predictive value and negative predictive value were 96.6% and 90.0%, respectively. Among nine patients in the true-negative category, five had colon cancers; and among three patients in the false-positive category, two had cancer of the cecal-appendiceal region as the underlying disease. CONCLUSION: CT examination is useful for patients with suspected appendicitis, but radiologists should be aware of the limitation of thick-sliced single helical CT. They should also be aware of the possibility of other diseases, including coincident abdominal neoplasms and underlying cecal-appendiceal cancer.

[A new method to obtain right-to-left shunt index of the lung using 99mTc-MAA pulmonary perfusion scintigraphy and first-pass dynamic data acquisition].

Generally a right-to-left shunt index in pulmonary area was calculated from total body and pulmonary area by scintillations count using 9mTc-MAA pulmonary perfusion scintigraphy. In this study, we devised a newly calculation method for right-to-left shunt index in pulmonary area from 9mTc-MAA pulmonary perfusion scintigraphy by first-pass dynamic data. We compared the proposed method with the conventional method in 26 patients (9 men and 17 women; 3-26 years old): 23 patients with congenital biliary atresia (CBA) post operation and the other 3 patients with right-to-left shunt from hepatopulmonary syndrome. As a result, there was a positive correlation of the index values between the proposed method and the conventional method (r = 0.929). Thus, the present method should be clinically useful.