Search

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

To determine the consistency of major hepatocellular carcinoma (HCC) features between CT and MRI based on Liver Imaging Reporting and Data System (LI-RADS) v2018 and to investigate the additional value on gadoxetic acid-enhanced MRI.Patients who underwent dynamic CT and gadoxetic acid-enhanced MRI within 1 month were investigated. Two radiologists evaluated the presence of major HCC features and categorized observations using LI-RADS v2018 algorithm. In addition, each observation was recorded as hyper-, iso-, or hypo-intensity on hepatobiliary-phase (HBP) images.Sixty-one patients with 110 observations were identified. Among 88 observations classified as LR-3, 4 or 5, arterial phase hyper-enhancement and washout appearance showed higher frequencies on CT than on MRI (75.0% vs. 58.0%, P 0.001, and 60.2% vs. 44.3%, P = 0.014, respectively). Of the 59 LR-3 observations categorized on MRI, 70.0% of observations with hypo-intensity on HBP images were HCCs, whereas 89.5% of observations with iso- or hyper-intensity on HBP images were non-HCCs (P 0.001) CONCLUSION: The frequencies of arterial phase hyper-enhancement and washout appearances were higher on CT than on gadoxetic acid-enhanced MRI. For LR-3 observations, adding the hepatobiliary-phase hypo-intensity to major features improved the diagnostic performance of MRI in distinguishing HCCs from non-HCC lesions.

Idiopathic pneumonia syndrome (IPS) is an acute lung dysfunction of non-infectious aetiology and a severe complication following haematopoietic stem cell transplantation (HSCT). Recently, the American Thoracic Society (ATS) updated the concept of IPS and extended the concept to a wider range; it defined IPS as "an idiopathic syndrome of pneumopathy after HSCT, with evidence of widespread alveolar injury and in which infectious aetiologies and cardiac dysfunction, acute renal failure, or iatrogenic fluid overload have been excluded." The ATS also categorised the presumed site of primary tissue injury into three patterns (pulmonary parenchyma, vascular endothelium, and airway epithelium), each of which has several entities. Since the therapeutic strategies for IPS are clearly different from those of infectious diseases, and therapeutic delay causes a poor prognosis, radiologists should be aware of some characteristic HRCT findings of IPS, which includes a wide spectrum of entities. In this article, the characteristic HRCT findings of these entities, including acute interstitial pneumonia/acute respiratory distress syndrome, eosinophilic pneumonia, non-cardiogenic capillary leak syndrome, diffuse alveolar haemorrhage, transfusion-related acute lung injury, organising pneumonia, and bronchiolitis obliterans syndrome, are shown.

With our methods, the lean body weight exhibited the strongest correlation with aortic and hepatic enhancement; therefore, we suggest it as the best body size index with which to determine the appropriate contrast medium dose at hepatic dynamic CT.

Diagnostic imaging is undoubtedly important in modern medicine, and final clinical decisions are often made based on it. Fortunately, Japan has the highest numbers of diagnostic imaging instruments, such as CT and MRI devices, and boasts easy access to them as well as a high level of diagnostic accuracy. In consequence, a very large number of imaging examinations are performed, but diagnostic instruments are installed in so many medical facilities that expert management of these examinations tends to be insufficient. Particularly, in order to avoid risks, clinicians have recently become indifferent to indications of imaging modalities and tend to rely on CT or MRI resulting in increasing the number of imaging examinations in Japan. This is a serious problem from the viewpoints of avoidance of unnecessary exposure and medical economy. Under these circumstances, the Japan Radiological Society and Japanese College of Radiology jointly initiated the preparation of new guidelines for diagnostic imaging. However, the field of diagnostic imaging is extremely wide, and it is impossible to cover all diseases. Therefore, in drafting the guidelines, we selected important diseases and focused on "showing evidence and suggestions in the form of clinical questions (CQs)" concerning clinically encountered questions and "describing routine imaging techniques presently considered to be standards to guarantee the quality of imaging examinations". In so doing, we adhered to the basic principles of assuming the readers to be "radiologists specializing in diagnostic imaging", "simultaneously respecting the global standards and attending to the situation in Japan", and "making the guidelines consistent with those of other scientific societies related to imaging". As a result, the guidelines became the largest ever, consisting of 152 CQs, nine areas of imaging techniques, and seven reviews, but no other guidelines in the world summarize problems concerning diagnostic imaging in the form of CQs. In this sense, the guidelines are considered to reflect the abilities of diagnostic radiologists in Japan. The contents of the guidelines are essential knowledge for radiologists, but we believe that they are also of use to general clinicians and clinical radiological technicians. While the number and contents of CQs are still insufficient, and while chapters such as those on imaging in children and emergency imaging need to be supplemented, the guidelines will be serially improved through future revisions. Lastly, we would like to extend our sincere thanks to the 153 members of the drafting committee who authored the guidelines, 12 committee chairpersons who coordinated their efforts, six members of the secretariat, and affiliates of related scientific societies who performed external evaluation.

We present the case of a 63-year-old woman presenting with a huge pelvic and retroperitoneal high flow arteriovenous malformation (AVM) causing high-output heart failure, who was treated with combined therapies, including transarterial embolization with n-butyl cyanoacrylate–iodized oil mixture (NBCA–lip) and coils for the right ovarian, both internal iliac, 3rd and 4th lumber arteries, venous sclerotherapy using coils and ethanolamine oleate (EO) for the right ovarian and both internal iliac veins with balloon-occluded retrograde transvenous obliteration technique, and direct percutaneous sclerotherapy using the NBCA–lip and EO for the large nidus of AVM under outflow control using occlusion balloon catheters.

Factors affecting the improvement in the lung perfused blood volume (LPBV) were evaluated based on the presence of intrapulmonary clots (IPCs) after anti-coagulation therapy using 64-slice dual-energy CT.96 patients exhibiting venous thromboembolism underwent initial and repeated LPBV examinations between December 2008 and July 2014. Fifteen patients were excluded due to pulmonary comorbidities, and a total of 81 patients were included in this study. Acute pulmonary embolism (PE) was diagnosed in 46 of the patients (56.7%). LPBV images were three-dimensionally reconstructed with two threshold ranges: 1-120 HU (V120) and 1-5 HU (V5), and the relative value of V5 per V120 expressed as %V5. These values were subsequently compared with indicators of the severity of PE, such as the D-dimer level, heart rate and CT measurements. This study was approved by the local ethics committee.In patients with IPCs, the D-dimer, V5 and %V5values were significantly larger (p≤0.01) in the initial LPBV, although these differences disappeared in subsequent LPBV after treatment. The right ventricular (RV) diameter, RV/left ventricular (RV/LV) diameter ratio and %V5 values were also significantly reduced, whereas the V5 value did not significantly decrease (p=0.07), but V120 value significantly increased (p0.001) after treatment. However, in patients with IPCs the change rate in %V5 [(subsequent-initial)/initial %V5] showed a better correlation with that in V5 (r=0.94, p0.001) rate than that in V120 (r=0.19, p=0.19) after treatment.Increased whole lung perfusion (V120) and a decreased low perfusion volume (V5) affect the improvement in the %V5 values after treatment.

To elucidate what kinds of lesions tend to be overlooked or misinterpreted and why they were overlooked or misinterpreted on chest radiographs in the diagnosis of community-acquired pneumonia (CAP) by comparing radiographic findings with HRCT findings. In 129 patients with CAP (107 bacterial and 22 atypical) and 105 healthy subjects, the chest radiographic findings were correlated with the HRCT findings. The diagnostic accuracy of each chest radiographic finding was evaluated by comparing it with the HRCT finding. The false negative rate of radiographic interpretation tended to be higher for nodules and thickening of the bronchial wall, especially in patients with atypical pneumonia. The most frequent reason for false negative interpretations of nodules and bronchial wall thickening was the overlapping of these findings with airspace consolidation or ground-glass opacity (GGO). Thin lesions were the most frequent reasons for the false negative interpretation of airspace consolidation and GGO. The chest radiographic interpretations of GGO and airspace consolidation were influenced by the thickness of lesions, and those of nodules and thickening of bronchial walls were influenced by coexisting GGO and airspace consolidation and may contribute to a misinterpretation of these lesions and an incorrect diagnosis of CAP.

BackgroundSublingual nitroglycerin capsules or spray is routinely used to treat anginal attacks and to maximally dilate the epicardial coronary arteries during coronary angiography. These dilated coronary vessels have an advantage, but increased heart rates were disadvantageous for coronary computed tomography angiography (CTA).PurposeThe influence of applying nitroglycerin was analyzed regarding the coronary diameter, coronary luminal attenuation, evaluable number of coronary segments, heart rate (HR), HR variability, the optimal reconstruction phase, and image scoring of CTA in the same patients using a 64-slice dual-source CT.Methods and subjectsFifty-two patients with atypical chest pain underwent coronary CTA before and after the administration of sublingual nitroglycerin without heart rate control. The coronary diameter and luminal attenuation were measured on short-axial images in each coronary segment. The coronary vasodilation ratios (VRs) were calculated from the coronary diameters at the same location before and after the use of nitroglycerin. The local institutional review board approved this study and written informed consent was obtained from all the patients.ResultsNo significant differences were noted in the HR variability or optimal reconstruction phase, despite an increase in HR after the use of nitroglycerin. Nitroglycerin significantly enlarged the coronary artery diameter, and VRs of each coronary segment ranged from 7.54% to 22.26%. As compared with baseline coronary diameter, VRs of minor segments (16.91%) were significantly larger than those of major segments (11.35%), and the magnitude of VR correlated with the baseline coronary diameter (r=−0.48, p

Background The aim of this study is to evaluate the accuracy of a newly developed quantitative method using 64-multislice computed tomography angiography (CTA) to detect coronary in-stent restenosis (ISR). Methods and results CTA was performed in 45 patients who underwent stent implantation (79 lesions) and the accuracy to diagnose ISR was evaluated by comparing with invasive coronary angiography (ICA). CTA was evaluated both visually and quantitatively using a new stent restenosis index (SRI) utilizing CT densities at proximal and distal artery lumen from the stented region and the correction value depending on the stent diameter. ICA showed 11 ISR (14%). The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for visual evaluation were 78%, 75%, 35%, 95%, and 76%, respectively. On the other hand, the quantitative evaluation using SRI represents 82%, 93%, 64%, 97%, and 91%, respectively. Conclusions Evaluation of ISR using SRI is superior to the visual estimation of CTA.

Background The cutoff value for assessing the severity of acute pulmonary thromboembolism (PTE) using relative volumetric evaluations of dual-energy perfusion computed tomography (DEpCT) is unclear. Purpose To determine the proper cutoff value for determining the severity of PTE using DEpCT volumetry. Material and Methods A total of 185 patients with venous thromboembolism were included in this study, of whom 61 were diagnosed with acute PTE. DEpCT images were three-dimensionally reconstructed at the following attenuation ranges: 1–2 HU (V2), 1–10 HU (V10), and 1–120 HU (V120). The ratios of low perfusion areas associated with each threshold range per V120 were also calculated, and the relative ratios were expressed as %V2 to %V10. These values were compared with factors indicating the severity of PTE, including the pulmonary arterial pressure, heart rate, CT angiographic obstruction index (CTOI), and right/left ventricular diameter ratio (RV/LV). Results The area under the curve (AUC) of %V2 was highest (0.783) among these values (95% confidence interval, 0.710–0.856) based on the presence of IPCs. The %V2 showed moderate correlations with CTOI (r = 0.36, P = 0.005) and RV/LV (r = 0.36, P = 0.004) in the patients with acute PTE. Conclusion Volumetric evaluations of DEpCT images using the lowest attenuation threshold range (1–2 HU) exhibit the best correlation with factors suggesting the severity of acute PTE.

To evaluate the high-resolution CT (HRCT) features of peripherally located small cell lung cancer (SCLC). We retrospectively reviewed the HRCT findings of 33 patients with peripherally located SCLC measuring 30 mm or less. The shape and marginal and internal characteristics of the nodules were evaluated. We also assessed the differences in these HRCT findings associated with the differences in the stages of disease. In 10 surgically treated cases, the HRCT-pathological correlations were evaluated. The findings of a well-defined margin (97.0 %), lobulation (78.8 %), thickening of the bronchovascular bundle (BVB) (57.6 %) and inhomogeneous enhancement (64.0 %) were common. A vermiform/branching and polygonal shape were observed in 33.3 and 21.2 % of cases, respectively. Air bronchograms (15.2 %) and marginal ground-glass opacity (GGO) (3.0 %) were less common findings. The vermiform/branching shape and thickening of the BVB were more frequently observed in non-stage I than in stage I tumors. The pathologic findings showed expansive tumor growth along the lymphatics and minimal necrosis between the tumor nests. A non-round shape and thickening of the BVB were common, while marginal GGO and air bronchogram were less common in small-sized, peripherally located SCLC. Furthermore, the vermiform/branching shape and thickening of the BVB suggested relatively advanced disease.

The aim of this study was to investigate the diagnostic ability of a completely automated computer-assisted diagnosis (CAD) system to detect metastases in bone scans by two patterns: one was per region, and the other was per patient.This study included 406 patients with suspected metastatic bone tumors who underwent whole-body bone scans that were analyzed by the automated CAD system. The patients were divided into four groups: a group with prostatic cancer (N = 71), breast cancer (N = 109), males with other cancers (N = 153), and females with other cancers (N = 73). We investigated the bone scan index and artificial neural network (ANN), which are parameters that can be used to classify bone scans to determine whether there are metastases. The sensitivities, specificities, positive predictive value (PPV), negative predictive value (NPV), and accuracies for the four groups were compared. Receiver operating characteristic (ROC) analyses of region-based ANN were performed to compare the diagnostic performance of the automated CAD system.There were no significant differences in the sensitivity, specificity, or NPV between the four groups. The PPVs of the group with prostatic cancer (51.0 %) were significantly higher than those of the other groups (P0.01). The accuracy of the group with prostatic cancer (81.5 %) was significantly higher than that of the group with breast cancer (68.6 %) and the females with other cancers (65.9 %) (P0.01). For the evaluation of the ROC analysis of region-based ANN, the highest Az values for the groups with prostatic cancer, breast cancer, males with other cancers, and females with other cancers were 0.82 (ANN = 0.4, 0.5, 0.6, 0.7, and 0.8), 0.83 (ANN = 0.7), 0.81 (ANN = 0.5), and 0.81 (ANN = 0.6), respectively.The special CAD system "BONENAVI" trained with a Japanese database appears to have significant potential in assisting physicians in their clinical routine. However, an improved CAD system depending on the primary lesion of the cancer is required to decrease the proportion of false-positive findings.

To evaluate clinical safety and efficacy of percutaneous transhepatic hybrid biliary prostheses for palliative treatment in patients with common bile duct obstruction caused by advanced malignancies. A total of 13 consecutive patients was treated with percutaneous transhepatic biliary endoprostheses concurrently using both plastic and metallic stents. Serum total bilirubin levels before and after stent placement were evaluated. The technical success rate, the period with no obstructive jaundice, patient survival and complications were also assessed. Median bilirubin levels decreased from 3.8 mg/dL before to 1.2 mg/dL after stent placement, and this difference was statistically significant. The median no-jaundice period after bile duct stent placement was 6.0 months (range: 2-11 months), and overall survival time was 7.0 months. Of the 13 patients, nine did not have recurrent jaundice by the time of death, whereas four (31%) had recurrent jaundice. A second intervention was performed in these four patients. A new plastic stent was placed and jaundice did not recur up to the time of death. No serious complications such as cholangitis, pancreatitis or bile duct perforation developed. Percutaneous transhepatic hybrid biliary endoprostheses using both plastic and metallic stents can be useful as non-invasive palliative treatment to relieve jaundice in patients with malignant obstructive jaundice.

The aim of this study was to evaluate the clinical effectiveness of covered Niti-S stent placement under multidetector CT and fluoroscopy guidance for the palliation of dysphagia in patients with cervical esophageal cancer. Under radiological imaging guidance using axial and sagittal CT scans, and fluoroscopy, Niti-S esophageal stents were placed in ten consecutive patients with complete obstruction caused by cervical esophageal cancer (9 men and 1 woman; age range = 54–79 years; mean age = 68.1 years) between February 2010 and December 2011. The procedure time and technical success rate were evaluated. Swallowing improvement was assessed by the following items: ability to eat and/or swallow (graded as follows: 3 = ability to eat normal diet, 2 = ability to eat semisolids, 1 = ability to swallow liquids, 0 = complete obstruction). Procedural and post-procedural complications were also evaluated. Survival (mean ± SD) was examined. The mean (±SD) procedure time was 40 ± 19 min (range = 21–69 min). Stent placement was technically successful in all patients; inadequate stent deployment did not occur in any case. Ability to eat and/or swallow was improved and scored 2.4 (score 3 in 5 cases, score 2 in 4 cases, score 1 in 1 case, and score 0 in no case) after stent placement. No major or post-procedural complications were encountered. The mean survival time was 131 ± 77 days (range = 31–259 days). Niti-S stents appeared to be a safe and effective device for the palliation of dysphagia caused by advanced cervical esophageal cancer. Multidetector CT and fluoroscopy image guidance helped the operators accurately place the stents in the cervical esophagus.

Little is known about disorder-specific biomarkers of bipolar disorder (BD) and major depressive disorder (MDD). Our aim was to determine a neural substrate that could be used to distinguish BD from MDD. Our study included a BD group (10 patients with BD, 10 first-degree relatives (FDRs) of individuals with BD), MDD group (17 patients with MDD, 17 FDRs of individuals with MDD), and 27 healthy individuals. Structural and functional brain abnormalities were evaluated by voxel-based morphometry and a trail making test (TMT), respectively. The BD group showed a significant main effect of diagnosis in the gray matter (GM) volume of the anterior cingulate cortex (ACC; p = 0.01) and left insula (p < 0.01). FDRs of individuals with BD showed significantly smaller left ACC GM volume than healthy subjects (p < 0.01), and patients with BD showed significantly smaller ACC (p < 0.01) and left insular GM volume (p < 0.01) than healthy subjects. The MDD group showed a tendency toward a main effect of diagnosis in the right and left insular GM volume. The BD group showed a significantly inverse correlation between the left insular GM volume and TMT-A scores (p < 0.05). Our results suggest that the ACC volume could be a distinct endophenotype of BD, while the insular volume could be a shared BD and MDD endophenotype. Moreover, the insula could be associated with cognitive decline and poor outcome in BD.

The effect of the procedural variability in image acquisition on the quantitative assessment of bone scan is unknown. Here, we have developed and performed preanalytical studies to assess the impact of the variability in scanning speed and in vendor-specific γ-camera on reproducibility and accuracy of the automated bone scan index (BSI). Methods: Two separate preanalytical studies were performed: a patient study and a simulation study. In the patient study, to evaluate the effect on BSI reproducibility, repeated bone scans were prospectively obtained from metastatic prostate cancer patients enrolled in 3 groups (Grp). In Grp1, the repeated scan speed and the γ-camera vendor were the same as that of the original scan. In Grp2, the repeated scan was twice the speed of the original scan. In Grp3, the repeated scan used a different γ-camera vendor than that used in the original scan. In the simulation study, to evaluate the effect on BSI accuracy, bone scans of a virtual phantom with predefined skeletal tumor burden (phantom-BSI) were simulated against the range of image counts (0.2, 0.5, 1.0, and 1.5 million) and separately against the resolution settings of the γ-cameras. The automated BSI was measured with a computer-automated platform. Reproducibility was measured as the absolute difference between the repeated BSI values, and accuracy was measured as the absolute difference between the observed BSI and the phantom-BSI values. Descriptive statistics were used to compare the generated data. Results: In the patient study, 75 patients, 25 in each group, were enrolled. The reproducibility of Grp2 (mean ± SD, 0.35 ± 0.59) was observed to be significantly lower than that of Grp1 (mean ± SD, 0.10 ± 0.13; P < 0.0001) and that of Grp3 (mean ± SD, 0.09 ± 0.10; P < 0.0001). However, no significant difference was observed between the reproducibility of Grp3 and Grp1 (P = 0.388). In the simulation study, the accuracy at 0.5 million counts (mean ± SD, 0.57 ± 0.38) and at 0.2 million counts (mean ± SD, 4.67 ± 0.85) was significantly lower than that observed at 1.5 million counts (mean ± SD, 0.20 ± 0.26; P < 0.0001). No significant difference was observed in the accuracy data of the simulation study with vendor-specific γ-cameras (P 5 0.266). Conclusion: In this study, we observed that the automated BSI accuracy and reproducibility were dependent on scanning speed but not on the vendor-specific γ-cameras. Prospective BSI studies should standardize scanning speed of bone scans to obtain image counts at or above 1.5 million. (Less)

Giant cell tumours (GCTs) are benign tumours commonly found in the long bones. Rarely, they may occur in the larynx, often resulting in hoarseness and anterior neck swelling. Since Wessely reported the first case of laryngeal GCT in 1940, 35 cases have been identified. Herein, we present a case of a 53-year-old male with GCT of the larynx that showed T1 and T2 hypointense signal on MRI, presumably owing to abundant haemosiderin deposition. We also discuss the imaging findings of CT and 18F-fludeoxyglucose positron emission tomography scans, as well as the pathological correlation.

To evaluate the high-resolution computed tomography (CT) findings of primary lung cancer with cavitation and compare the findings in adenocarcinoma and squamous cell carcinoma.The high-resolution CT findings of tumours with cavitation were retrospectively evaluated in 60 patients. Forty-seven of the lesions were diagnosed as adenocarcinomas; 13 were diagnosed as squamous cell carcinomas. The diameters of the tumour and cavity, the maximum thickness of the cavity wall, shape of the cavity wall, the number of cavities, and the presence of ground-glass opacity, bronchial obstruction, intratumoural bronchiectasis, emphysema, and honeycombing were evaluated. The mechanisms of cavity formation were examined according to the pathological features.The maximum thickness of the cavity wall was significantly greater in squamous cell carcinomas than in adenocarcinomas (p=0.002). Ground-glass opacity and intratumoural bronchiectasis were significantly more common in adenocarcinomas than in squamous cell carcinomas (p0.001 and p=0.040, respectively). Regarding the pathological findings, intratumoural bronchiectasis with or without alveolar wall destruction contributed to a significant difference between adenocarcinoma and squamous cell carcinoma (p0.001; odds ratio [OR], 20.35; 95% confidence interval [CI], 3.87-107.10).The cavity wall tends to be thicker in squamous cell carcinomas than in adenocarcinomas. The presence of ground-glass opacity and intratumoural bronchiectasis is strongly suggestive of adenocarcinoma.

The classification of diffuse lung opacities in high-resolution computed tomography(HRCT) images is an important step for developing a computer-aided diagnosis(CAD) system. In designing the CAD system for classifying diffuse lung opacities in HRCT images, a histogram feature has been shown to be effective. In order to improve further the classification performance of the CAD system, we have proposed the use of a local histogram feature vector. The experimental results show that the proposed method leads to clear improvement of the classification performance.

The purpose of this study was to compare the proton-density (PD)-weighted fast spin-echo (FSE) and fast-recovery FSE (FRFSE) sequences for the evaluation of the anatomical structures of the knee.24 healthy volunteers who underwent MRI by both sagittal PD-weighted FSE and FRFSE sequences were evaluated. The signal-to-noise ratio, contrast-to-noise ratio (CNR) and anatomical detail visualisation were compared for the two techniques.The mean CNRs and reader ratings for both readers were significantly higher for the PD-weighted FRFSE images than for the PD-weighted FSE images in the cartilages/the femorotibial joint effusion and the cruciate ligaments/the effusion around the cruciate ligaments; however, the mean CNRs and reader ratings for both readers were significantly higher for the PD-weighted FSE sequences than for the PD-weighted FRFSE sequences in the cartilages/the menisci and the cruciate ligaments.The main advantages of the PD-weighted FRFSE sequence are the increase in contrast between fluid and non-fluid tissues and the time saved by using the procedure. However, in the absence of joint effusion, the PD-weighted FRFSE sequence generates a poorer contrast between the cartilage and meniscus, the cruciate ligaments and fat of the intercondylar fossa.

The purpose of the study was to evaluate the respiratory variation of the extrahepatic bile duct in morphology including shape, length and duct diameter on the breath-hold magnetic resonance cholangiopancreatography (MRCP) obtained during deep inspiration and deep expiration in patients with or without biliary diseases.This study included 102 patients with or without biliary diseases. Breath-hold MRCP was obtained twice during the end-inspiration and the end-expiration. MRCP images were evaluated for the length, maximal diameter and "bowing" of the extrahepatic bile duct.In the normal group, the mean maximal diameter of the extrahepatic bile duct was significantly larger on the end-inspiratory MRCP (8.0 ± 2.0 mm) than on the end-expiratory MRCP (7.3 ± 1.8 mm) (P.0001), while it was not significantly different in the dilated group. In the normal group, 25 (39%) of 65 patients had an increase in the mean maximal diameter of more than 1 mm at the end-inspiration, whereas 4 (11%) of 37 patients in the dilated group had it. The bowing of the extrahepatic bile duct on the end-inspiratory MRCP was observed in 60 (92%) of 65 normal patients, while it was seen in 22 (60%) of 37 patients with biliary dilatation (P.0001).Deep inspiratory and expiratory MRCP demonstrated the respiratory variations of the extrahepatic bile duct in the shape (bowing), length and maximal duct diameter in patients with nondilated bile ducts. Awareness of this normal phenomenon will be important for the correct interpretation of MRCP in patients with or without biliary diseases.

BACKGROUND Patients with head and neck cancer frequently require gastrostomy feeding. The aim of this study was to evaluate the safety and feasibility of percutaneous radiologic gastrostomy with push-type gastrostomy tubes using a rupture-free balloon (RFB) catheter under computed tomography (CT) and fluoroscopic guidance in patients with head and neck cancer with swallowing disturbance or trismus. METHODS Percutaneous CT and fluoroscopic gastrostomy placement of push-type gastrostomy tubes using a RFB catheter was performed in consecutive patients with head and neck cancer between April 2007 and July 2010. The technical success, procedure duration, and major or minor complications were evaluated. RESULTS Twenty-one patients (14 men, 7 women; age range, 55-78 years; mean age, 69.3 years) underwent gastrostomy tube placement. The tumor location was the pharynx (n = 8), oral cavity (n = 7), and gingiva (n = 6). Gastrostomy was performed in 15 patients during treatment and 6 patients after treatment. Percutaneous radiologic gastrostomy was technically successful in all patients. The median procedure time was 35 ± 19 (interquartile range) minutes (range, 25-75). The average follow-up time interval was 221 days (range, 10-920 days). No major complications related to the procedure were encountered. No tubes failed because of blockage, and neither tube dislodgement nor intraperitoneal leakage occurred during the follow-up periods. CONCLUSION Percutaneous CT and fluoroscopic-guided gastrostomy with push-type tubes using a RFB catheter is a relatively safe and effective means of gastric feeding, with high success and low complication rates in patients with head and neck cancer in whom endoscopy was not feasible.

To evaluate the high-resolution computed tomography (HRCT) findings of novel influenza virus (n-IFV) pneumonia and compare them with the findings for seasonal (s-IFV) pneumonia. We evaluated 29 cases of pure IFV pneumonia that occurred between 1990 and 2010. We evaluated the existence, extent, and patterns of HRCT findings and compared these features between s-IFV and n-IFV. Consolidation was less frequent in s-IFV than in n-IFV (40.0 vs. 84.2%, respectively; p = 0.014). Consolidation with a loss of volume was frequent in n-IFV (62.5%). There was no significant difference in the occurrence of ground-glass opacity (GGO) between s-IFV and n-IFV (100 vs. 84.2%, respectively). GGO with reticular opacities was more frequent in s-IFV than in n-IFV (70.0 vs. 25.0%, respectively; p = 0.024). The frequency of nodules was not significantly different between the two groups. The mosaic pattern was more frequent in s-IFV than in n-IFV patients (80.0 vs. 15.8%, respectively; p = 0.0007). Mucoid impaction was more frequent in patients with n-IFV than with s-IFV (52.6 vs. 10.0%, respectively; p = 0.025). Consolidation and mucoid impaction were more frequent in n-IFV, whereas GGO with reticular opacities and a mosaic pattern occurred more frequently in s-IFV; otherwise, there were no significant differences between the two groups.

To clarify whether the uptake of SPIO increases or decreases in areas of fatty change compared with surrounding areas of nonfatty change at SPIO-enhanced MR imaging.Approval for this retrospective study was obtained from our institutional review board. This study included 14 patients with nondiffuse fatty infiltration of the liver who underwent SPIO-enhanced MR imaging. Additionally, 30 patients without nondiffuse fatty infiltration of the liver were also evaluated.Among 14 patients, areas of fatty change showed relatively high signal intensity in 7 patents, indicating decreased uptake of SPIO in areas of fatty change. In these 7 patients, 4 had mild cirrhosis and 3 did not have cirrhosis. The mean percentage of signal intensity loss (42%) of fatty areas was significantly lower (p0.007) than that of adjacent areas of nonfatty change (52%). In the remaining 7 of 14 patients, areas of fatty change showed relatively low signal intensity, indicating increased uptake of SPIO in areas of fatty change. Among these 7 patients, 6 had advanced cirrhosis. The mean percentage of signal intensity loss (47%) of fatty areas was significantly higher (p0.008) than that of adjacent areas of nonfatty change (31%).The uptake of SPIO generally decreased in areas of fatty change compared with normal liver parenchyma at SPIO-enhanced MR imaging. However, in patients with advanced cirrhosis, areas of fatty change shows relatively low signal intensity because the uptake of SPIO in surrounding areas of nonfatty change severely decreased probably due to liver fibrosis.

The purpose of this study was to evaluate the image quality (IQ) of dual-source CT (DSCT) versus single-source CT (SSCT). A total of 100 patients underwent 64-section CT coronary angiography (50 DSCT, 50 SSCT). Three observers evaluated the IQ of each coronary segment using a four-point scale (1, excellent; 2, good; 3, fair; 4, no assessment). The IQ of DSCT coronary angiography was compared with SSCT coronary angiography on a per-patient, per-vessel, and per-segment basis using the chi-squared test. The DSCT image quality score (IQS) was significantly lower on a per-patient basis and per-vessel basis for all vessels and on a per-segment basis for some segments (1, 2, 4PD, 4AV, 7, 9, 11, 12, 13) compared with SSCT. The DSCT IQS was significantly lower for certain segments (2, 4PD, 11, 13) with high heart rates (≥70 beats/min). The DSCT IQS was significantly lower for certain segments (1, 2, 3, 4PD, 4AV, 7, 8, 9, 10, 12, 13) with low heart rates (

OBJECTIVE To determine whether it is possible to use bone single-photon emission tomography (SPECT) as a substitute for magnetic resonance (MR) imaging for differentiating malignant from benign vertebral compression fractures (VCFs). METHODS Ninety-seven fractures in patients who underwent both bone SPECT and MR imaging were included in our study. These 97 fractures were divided into two groups: malignant and benign VCFs. Two radiologists separately classified VCFs into malignant and benign according to the criteria for classifying VCFs on the planar, SPECT, and MR imaging as malignant or benign, as reported by many investigators earlier. In addition, 97 fractures were divided into two groups based on the MR images: VCFs with complete and partial replacement of the normal fatty marrow. The sensitivity, specificity, and accuracy of both the observers were calculated. RESULTS The accuracy of the MR images was significantly greater than that of the SPECT images for both the observers (observer 1, P

The purpose of our study was to evaluate the correlation between the Kellgren-Lawrence (KL) radiographic score and the femoral and tibial cartilage volumes determined by MRI in patients with knee osteoarthritis. The effect of meniscal tears and extrusion on the cartilage volume was also examined.Knee cartilage was evaluated by MRI in 74 patients (20 men and 54 women) who were categorized according to the KL score. Sagittal fat-suppressed 3D spoiled gradient-echo images were obtained to calculate the cartilage volume. The cartilage volume was determined for the lateral femoral cartilage, medial femoral cartilage, lateral tibial cartilage, and medial tibial cartilage. The femoral condylar bone volume was measured to adjust for bone size in each cartilage volume measurement.After adjusting for age, sex, and femoral condylar bone volume, the cartilage volumes were significantly different between the grades in all compartments. Additionally, significant correlations were observed between the KL score and the adjusted cartilage volumes of lateral femoral cartilage and lateral tibial cartilage without a meniscal tear and between the KL score and the adjusted cartilage volume of medial femoral cartilage with and without a meniscal tear.These findings showed a significant negative association between cartilage volume and the KL score. The cartilage volume of medial femoral cartilage may be more affected by the severity of osteoarthritis grade than the presence of a meniscal tear. In contrast, the cartilage volume in the lateral tibiofemoral compartment may be easily affected by the presence of a meniscal tear.

The effect of computed tomography (CT) density-based, non-uniform photon attenuation correction (AC) on lung perfusion distribution and the clinical significance were evaluated.40 patients with pulmonary emphysema, 32 with pulmonary thromboembolism, 25 with lung cancer and 8 normal controls underwent deep-inspiratory breath-hold (DIBrH) Tc-99m-MAA perfusion SPECT, using a dual-head SPECT system and a respiratory tracking device. Scatter-corrected DIBrH SPECT was automatically co-registered with DIBrH CT. AC of DIBrH SPECT was performed using an attenuation coefficient map of a variable-effective linear coefficient calculated from CT pixel density of the co-registered DIBrH CT. The effect of AC on pulmonary perfusion was evaluated by comparison with uncorrected SPECT.After AC, lung perfusion in normal lungs was increased predominantly at deep lungs near the mediastinum and vertebrae and at the upper-middle lungs, with systematic increases of radioactivity (145 ± 28%) and significant enhancement of physiological gravitational ventral-dorsal gradient (P0.01). Throughout the lung diseases, AC significantly enhanced perfusion defect clarity and heterogeneity (P0.001), without noticeable artifacts. The correlation between perfusion heterogeneity and the lung diffusing capacity for carbon monoxide was significantly improved in patients with emphysema (P0.005).CT density-based, non-uniform AC of DIBrH perfusion SPECT provides better assessment of physiologic or impaired perfusion distributions in normal and lung diseases.

PURPOSE Lung perfusion impairment in patients with pulmonary arteriovenous fistula (AVF) was evaluated by automated deep inspiratory breath-hold (DIBrH) perfusion single-photon emission computed tomography (SPECT)-CT fusion images. METHODS Participants were 14 patients with a single (N=6) or multiple nodular AVFs (N=8) diagnosed by contrast-enhanced CT scan and/or pulmonary angiography. After the injection of 185MBq Tc-99m-macroaggregated albumin, a whole-body scan was obtained to quantify an intrapulmonary right-to-left shunt. Subsequently, DIBrH SPECT was obtained using the continuous rotating acquisition mode of a dual-headed SPECT system, which was automatically coregistered with DIBrH CT. The anatomic relationship between AVF and perfusion defects was assessed on the fusion images. RESULTS The whole-body scan depicted systemic organs indicating the presence of an intrapulmonary right-to-left shunt in all the patients. DIBrH SPECT showed 34 perfusion defects in these patients, which were located at the AVF and in the surrounding lungs of the AVF on the fusion images, regardless of the absence of morphologic abnormality on CT in all the patients. These defects were considered to be caused by the 'steal phenomenon' associated with the high and fast pulmonary arterial flow to each AVF, which were more extensive and severe in the multiple AVFs compared with a single AVF (P=0.0012), occasionally extending to the entire lobe with AVF or even to the adjacent lobe. In five patients, the fusion images detected a total of six tiny AVFs with unexpectedly extensive 'steal phenomenon'-induced defects, which had been missed by other radiological imaging techniques. The summed value of the shunt index estimated by the whole-body scan and the lung perfusion defect extent estimated by DIBrH SPECT was significantly correlated with PaO2 in all the patients (P < 0.0001), with a better correlation compared with the shunt index alone. CONCLUSION In addition to the right-to-left shunt, 'steal phenomenon'-induced perfusion defects are common in the surrounding lung of pulmonary nodular AVF and cause hypoxemia. DIBrH SPECT-CT fusion images contribute to the objective evaluation of 'steal phenomenon'-induced lung perfusion impairment in AVF and the detection of tiny, subtle AVFs that may be missed by other radiological imaging techniques.

The purpose of this study was to evaluate the safety and feasibility of percutaneous radiologic gastrostomy placement of push-type gastrostomy tubes using a rupture-free balloon (RFB) catheter under computed tomography (CT) and fluoroscopic guidance. A total of 35 patients (23 men and 12 women; age range 57–93 years [mean 71.7]) underwent percutaneous CT and fluoroscopically guided gastrostomy placement of a push-type gastrostomy tube using an RFB catheter between April 2005 and July 2008. Technical success, procedure duration, and complications were analyzed. Percutaneous radiologic gastrostomy placement was considered technically successful in all patients. The median procedure time was 39 ± 13 (SD) min (range 24–78). The average follow-up time interval was 103 days (range 7–812). No major complications related to the procedure were encountered. No tubes failed because of blockage, and neither tube dislodgement nor intraperitoneal leakage occurred during the follow-up period. The investigators conclude that percutaneous CT and fluoroscopically guided gastrostomy placement with push-type tubes using an RFB catheter is a safe and effective means of gastric feeding when performed by radiologists.

PURPOSE: Cross-sectional lung ventilation (V)-perfusion (Q) imbalance in primary pulmonary arterial hypertension (PAH) and passive pulmonary hypertension (PH) was characterized by automated V/Q single-photon emission computed tomography (SPECT). MATERIALS AND METHODS: Technegas/macro-aggregated albumin SPECT-derived V/Q SPECT and V/Q profile were automatically built to characterize cross-sectional lung V-Q imbalance in 12 patients with primary (idiopathic or familial) PAH and 15 patients with passive PH associated with left ventricular dysfunction or failure. The abnormality of V/Q distribution in these patients was correlated with PaO2 and pulmonary arterial pressure and with lung morphologic changes on computed tomography (CT). RESULTS: Markedly low V/Q ratios (reverse V-Q mismatch) in the background lungs with heterogeneous V/Q distribution was seen in 12 of the 12 (100%) patients with primary PAH and in 10 of the 15 (66%) patients with passive PH, which were predominantly seen in the upper lung zone. Including these regions with reverse V-Q mismatch, the V/Q profile frequently showed flattened peaks with asymmetric and broadened V/Q distribution in all patients, with significant correlation between the standard deviation of V/Q ratios in the entire lungs and PaO2 and mean pulmonary arterial pressure (both; P

There has been concern regarding the usefulness of diffusion-weighted imaging (DWI) to evaluate the ischemic lesions associated with carotid artery stent placement (CAS). Some small lesions may be detected not by standard DWI but by thin-slice DWI alone, since most of the cerebral lesions are very small in size and clinically silent. The purpose of this study is to compare the detectability of the small ischemic lesions after CAS by standard and thin-slice DWI. Both standard DWI with slice thickness of 6 mm and thin-slice DWI with slice thickness of 2 mm were obtained at the same MR examination within 2 to 7 days after 20 procedures of CAS in 17 patients. Number and measured diameter size of the detected lesions on both DWI were compared. All CAS procedures in 17 patients were successfully completed. The focal ischemic lesions were detected in 14 of 20 on thin-slice DWI and seven examinations on standard DWI. The total numbers of hyperintense lesions were 31 on thin-slice DWI and ten on standard DWI (p

Tc-99m-Technegas–MAA single photon emission computed tomography (SPECT)-derived ventilation (V)/perfusion (Q) quotient SPECT was used to assess lung V–Q imbalance in patients with pulmonary emphysema. V/Q quotient SPECT and V/Q profile were automatically built in 38 patients with pulmonary emphysema and 12 controls, and V/Q distribution and V/Q profile parameters were compared. V/Q distribution on V/Q quotient SPECT was correlated with low attenuation areas (LAA) on density-mask computed tomography (CT). Parameters of V/Q profile such as the median, standard deviation (SD), kurtosis and skewness were proposed to objectively evaluate the severity of lung V–Q imbalance. In contrast to uniform V/Q distribution on V/Q quotient SPECT and a sharp peak with symmetrical V/Q distribution on V/Q profile in controls, lung areas showing heterogeneously high or low V/Q and flattened peaks with broadened V/Q distribution were frequently seen in patients with emphysema, including lung areas with only slight LAA. V/Q distribution was also often asymmetric regardless of symmetric LAA. All the proposed parameters of V/Q profile in entire lungs of patients with emphysema showed large variations compared with controls; SD and kurtosis were significantly different from controls (P

This is a report of fluoro-deoxy-glucose positron emission tomography/computed tomography (F-18-FDG PET/CT) findings in a case of T-cell lymphoma-associated hemophagocytic syndrome, with “periportal low attenuation” and edematous gall-bladder wall thickening. FDG PET/CT showed diffuse inten

This is a case study of a 66-year-old woman who had a vascular malformation of the small bowel that was visualized on computed tomography enteroclysis (CTE). She presented with repeated tarry stool and severe anemia. Although the source of bleeding was not identified on upper and lower gastrointestinal endoscopy, active bleeding was revealed by capsule endoscopy in the deep jejunum. The cause of bleeding was not found on capsule endoscopy. CTE was requested as double-balloon endoscopy would have been difficult because of strong adhesion of the small intestine. A continual subtle vascular malformation of the jejunum, starting from the third jejunal branch end, was demonstrated on CTE with dynamic contrast enhancement. Because this vascular malformation was considered the cause of small intestinal bleeding, selective arterial coil embolization was performed. After embolization, the repeated tarry stool disappeared and the severe anemia dramatically improved. CTE may be a safe and useful method for determining the cause of small intestinal bleeding and for subsequent therapy.

The purpose of this study was to assess the value of the fast STIR sequence in comparison with the T1-weighted fat-suppressed contrast-enhanced sequence in the evaluation of soft-tissue tumors.Sixty-seven soft-tissue tumors imaged with both STIR and T1-weighted fat-suppressed contrast-enhanced sequences were evaluated. The signal-to-noise and contrast-to-noise ratios of the tumors in comparison with normal muscle, bone marrow, and fat were measured. Subjective image contrast between soft-tissue tumors and the nearest normal tissue was evaluated by two observers. The observers classified the soft-tissue tumors as benign or malignant using a 5-point scale, and sensitivity, specificity, and accuracy were calculated. The results of the two readings were assessed with receiver operating characteristic analysis.The contrast-to-noise ratios of all tumors in comparison with muscle (p0.01), bone marrow (p0.05), and fat (p0.05) were significantly higher on the fast STIR images than on the T1-weighted fat-suppressed contrast-enhanced images. Both observers' mean ratings of benign, malignant, and all tumors in comparison with muscle on fast STIR images were significantly higher than those on T1-weighted fat-suppressed contrast-enhanced images. For both observers, the mean sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve in evaluation of the fast STIR images did not differ significantly from those in evaluation of the T1-weighted fat-suppressed contrast-enhanced images.The fast STIR sequence is excellent for evaluation of soft-tissue tumors, and contrast-enhancement is not always needed.

Nonspecific interstitial pneumonia (NSIP) and usual IP (UIP) preferentially involve subpleural lung zones (SPLZ), and may result in characteristic regional lung function impairment. The aim of this study was to characterize cross-sectional lung ventilation (V)-perfusion (Q) imbalance in these disorders on automated V/Q quotient single photon emission computed tomography (SPECT).99mTc-technegas/macroaggregated albumin SPECT-derived V/Q quotient SPECT and V/Q profile were automatically built for assessment of cross-sectional lung V-Q imbalance in 38 patients with NSIP or UIP. The findings of V/Q quotient SPECT were correlated with lung CT morphology. The results were compared with 12 healthy nonsmoker controls and 48 patients with chronic obstructive pulmonary disease.V/Q quotient SPECT showed 81 crescentic SPLZ with high V/Q ratios in 32 patients (84%) with NSIP or UIP, which were not observed in controls and patients with chronic obstructive pulmonary disease. Sixty-three (77.7%) of them were located at high-attenuation areas (reticular and/or ground-glass opacities) with or without small cystic air spaces (honeycombing and/or traction bronchiectasis) on CT, and 12 (14.8%) at normal lung areas. V/Q profile at the lung sections with crescentic SPLZ with high V/Q ratios showed flattened peaks with broadened V/Q ratio distribution compared with controls, and standard deviation of V/Q ratios in the entire lungs was significantly correlated with partial oxygen arterial blood pressure (P = 0.0009) and predicted diffusing capacity of the lungs for carbon monoxide (P = 0.0139). Five of eight patients with NSIP or UIP and with worsening of hypoxemia showed an extension of SPCZ with high V/Q ratios on follow-up V/Q quotient SPECT, without significant changes on CT.A high prevalence of crescentic SPLZ with high V/Q ratios is a characteristic feature of lung V-Q imbalance causing alveolar gas exchange impairment in NSIP and UIP.

The aim of this study was to determine the adequate MR sequence for the lesion conspicuity of hepatocellular lesions with increased iron uptake on superparamagnetic iron oxide (SPIO)-enhanced MRI.SPIO-enhanced MRI was performed using a 1.5-T system. Among 25 patients with hypovascular hepatocellular nodules on contrast-enhanced dynamic CT (no early enhancement at arterial phase and hypoattenuation at equilibrium phase), 39 lesions with increased iron uptake on SPIO-enhanced MRI were evaluated. SPIO-enhanced MRI included (1) T1-weighted in-phase gradient recalled echo (GRE) images, (2) T2-weighted fast spin echo (FSE) images, (3) T2*-weighted GRE with moderate TE (7 ms) and (4) long TE (12 ms). The lesion-to-liver contrast-to-noise ratios of the hepatocellular nodule and the signal-to-noise ratio (SNR) of the hepatic parenchyma were calculated by one radiologist for a quantitative assessment. MR images were reviewed retrospectively by two independent radiologists to compare the subjective lesion conspicuity in each image set based on a four-point rating scale.The mean lesion-to-liver contrast-to-noise ratios with T2*-weighted GRE with moderate TE (7 ms) was highest (5.79+/-3.71) and was significantly higher than those with T1-weighted, in-phase images (3.79+/-3.23, P.01), T2-weighted images (2.72+/-1.52, P.001) and T2*-weighted GRE with long TE (12 ms) (3.93+/-2.69, P.05). The subjective rating of lesion conspicuity was best on the T2*-weighted GRE with moderate TE (7 ms), followed by that on the T2*-weighted GRE with moderate TE (7 ms; P.05).T2*-weighted GRE sequence with moderate TE (7 ms) showed high lesion-to-liver contrast-to-noise ratios in hepatocellular lesions with increased iron uptake on SPIO-enhanced MRI, indicating better lesion conspicuity of hypointense hepatocellular nodules in cirrhosis or chronic hepatitis.