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A 77-year-old man arrived at our hospital with bilateral shoulder pain persisting for several months and headache for 1 month. Giant cell arteritis with polymyalgia rheumatica was suspected. However, considering his medical history of testing positive for syphilis, we submitted a sample for a syphilis serology test, which yielded positive results. The Treponema pallidum hemagglutination assay of cerebrospinal fluid was positive, and a temporal artery biopsy revealed vasculitis, confirming the diagnosis of tertiary syphilis. He was successfully treated for two weeks with penicillin G infusions. Symptoms reminiscent of giant cell arteritis and polymyalgia rheumatica may reveal syphilis, which is called the "great imitator."

Purpose To evaluate whether deep learning reconstruction (DLR) accelerates the acquisition of 1.5-T magnetic resonance imaging (MRI) knee data without image deterioration. Materials and methods Twenty-one healthy volunteers underwent MRI of the right knee on a 1.5-T MRI scanner. Proton-density-weighted images with one or four numbers of signal averages (NSAs) were obtained via compressed sensing, and DLR was applied to the images with 1 NSA to obtain 1NSA-DLR images. The 1NSA-DLR and 4NSA images were compared objectively (by deriving the signal-to-noise ratios of the lateral and the medial menisci and the contrast-to-noise ratios of the lateral and the medial menisci and articular cartilages) and subjectively (in terms of the visibility of the anterior cruciate ligament, the medial collateral ligament, the medial and lateral menisci, and bone) and in terms of image noise, artifacts, and overall diagnostic acceptability. The paired t-test and Wilcoxon signed-rank test were used for statistical analyses. Results The 1NSA-DLR images were obtained within 100 s. The signal-to-noise ratios (lateral: 3.27 ± 0.30 vs. 1.90 ± 0.13, medial: 2.71 ± 0.24 vs. 1.80 ± 0.15, both p p Conclusion Compared with the 4NSA images, the 1NSA-DLR images exhibited less noise, higher overall image quality, and allowed more precise visualization of the menisci and ligaments.

Purpose The purpose of this study was to evaluate whether deep learning reconstruction (DLR) improves the image quality of intracranial magnetic resonance angiography (MRA) at 1.5 T. Materials and methods In this retrospective study, MRA images of 40 patients (21 males and 19 females; mean age, 65.8 ± 13.2 years) were reconstructed with and without the DLR technique (DLR image and non-DLR image, respectively). Quantitative image analysis was performed by placing regions of interest on the basilar artery and cerebrospinal fluid in the prepontine cistern. We calculated the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for analyses of the basilar artery. Two experienced radiologists evaluated the depiction of structures (the right internal carotid artery, right ophthalmic artery, basilar artery, and right superior cerebellar artery), artifacts, subjective noise and overall image quality in a qualitative image analysis. Scores were compared in the quantitative and qualitative image analyses between the DLR and non-DLR images using Wilcoxon signed-rank tests. Results The SNR and CNR for the basilar artery were significantly higher for the DLR images than for the non-DLR images (p p p p = 0.072–0.565), were also significantly higher for the DLR images than for the non-DLR images. Conclusion DLR enables the production of higher quality 1.5 T intracranial MRA images with improved visualization of arteries.

Radiation therapy (RT) continues to play a central role as an effective therapeutic modality for a variety of tumors and vascular malformations in the central nervous system. Although the planning and delivery techniques of RT have evolved substantially during the past few decades, the structures surrounding the target lesion are inevitably exposed to radiation. A wide variety of radiation-induced changes may be observed at posttreatment imaging, which may be confusing when interpreting images. Histopathologically, radiation can have deleterious effects on the vascular endothelial cells as well as on neuroglial cells and their precursors. In addition, radiation induces oxidative stress and inflammation, leading to a cycle of further cellular toxic effects and tissue damage. On the basis of the time of expression, radiation-induced injury can be divided into three phases: acute, early delayed, and late delayed. Acute and early delayed injuries are usually transient and reversible, whereas late delayed injuries are generally irreversible. The authors provide a comprehensive review of the timeline and expected imaging appearances after RT, including the characteristic imaging features after RT with concomitant chemotherapy. Specific topics discussed are imaging features that help distinguish expected posttreatment changes from recurrent disease, followed by a discussion on the role of advanced imaging techniques. Knowledge of the RT plan, the amount of normal structures included, the location of the target lesion, and the amount of time elapsed since RT is highly important at follow-up imaging, and the reporting radiologist should be able to recognize the characteristic imaging features after RT and differentiate these findings from tumor recurrence. ©RSNA, 2020.

To understand the latest pediatric computed tomography (CT) exposure required for the revision of national DRLs.A questionnaire was sent to 409 facilities where the members of the Japanese Society of Radiological Technology and the Japanese Society of Pediatric Radiology are enrolled. We investigated the imaging conditions, CTDIIn all, 43 facilities (11%) responded to our survey. multi detector-row CT (MDCT) systems were available in all surveyed facilities. More than 98% of the MDCT systems had more than 64 detector rows. The CTDIIt is necessary to review the imaging protocol with the attending physician and radiologist and consider further optimization of medical exposure.

To assess the possibility of reducing the image acquisition time for diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) by denoising with deep learning-based reconstruction (dDLR).Seventeen patients with prostate cancer who underwent DWIBS by 1.5 T magnetic resonance imaging with a number of excitations of 2 (NEX2) and 8 (NEX8) were prospectively enrolled. The NEX2 image data were processed by dDLR (dDLR-NEX2), and the NEX2, dDLR-NEX2, and NEX8 image data were analyzed. In qualitative analysis, two radiologists rated the perceived coarseness, conspicuity of metastatic lesions (lymph nodes and bone), and overall image quality. The contrast-to-noise ratios (CNRs), contrast ratios, and mean apparent diffusion coefficients (ADCs) of metastatic lesions were calculated in a quantitative analysis.The image acquisition time of NEX2 was 2.8 times shorter than that of NEX8 (3 min 30 s vs 9 min 48 s). The perceived coarseness and overall image quality scores reported by both readers were significantly higher for dDLR-NEX2 than for NEX2 (P = 0.005-0.040). There was no significant difference between dDLR-NEX2 and NEX8 in the qualitative analysis. The CNR of bone metastasis was significantly greater for dDLR-NEX2 than for NEX2 and NEX8 (P = 0.012 for both comparisons). The contrast ratios and mean ADCs were not significantly different among the three image types.dDLR improved the image quality of DWIBS with NEX2. In the context of lymph node and bone metastasis evaluation with DWIBS in patients with prostate cancer, dDLR-NEX2 has potential to be an alternative to NEX8 and reduce the image acquisition time.

The medical staff involved in fluoroscopy-guided procedures are at potential risks of radiation-induced cataract. Therefore, proper monitoring of the lens doses is critical, and radiation protection should be provided to the maximum extent that is reasonably achievable. The collar dosimeter is necessary to avoid underestimation of the lens dose, and the third dosimeter behind the protective eyewear would be helpful for those who are likely to exceed the dose limit. The reduction of the patient doses will correspondingly reduce the staff doses. Proper placement of the ceiling-mounted shields and minimization of the face-to-glass gap are the keys to effective shielding. The optimization of procedures and devices that help maintain a distance from the irradiated area and to prevent the looking-up posture will substantially reduce the lens dose.

T2-weighted imaging (T2WI) is a key sequence of MRI studies of the pancreas. The single-shot fast spin echo (single-shot FSE) sequence is an accelerated form of T2WI. We hypothesized that denoising approach with deep learning-based reconstruction (dDLR) could facilitate accelerated breath-hold thin-slice single-shot FSE MRI, and reveal the pancreatic anatomy in detail.To assess the image quality of thin-slice (3 mm) respiratory-triggered FSE T2WI (Resp-FSE) and breath-hold fast advanced spin echo with and without dDLR (BH-dDLR-FASE and BH-FASE, respectively) at 1.5 T.MR images of 42 prospectively enrolled patients with suspected pancreaticobiliary disease were obtained at 1.5 T. We qualitatively and quantitatively evaluated image quality of BH-dDLR-FASE related to BH-FASE and Resp-FSE.The scan time of BH-FASE was significantly shorter than that of Resp-FSE (30 ± 4 s and 122 ± 25 s, p 0.001). Qualitatively, dDLR significantly improved BH-FASE image quality, and the image quality of BH-dDLR-FASE was significantly better than that of Resp-FSE; as quantitative parameters, the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of BH-dDLR-FASE were also significantly better than those of Resp-FSE. The BH-dDLR-FASE sequence covered the entire pancreas and liver and provided overall image quality rated close to excellent.The dDLR technique enables accelerated thin-slice single-shot FSE, and BH-dDLR-FASE seems to be clinically feasible.

This study aimed to evaluate whether the image quality of 1.5T magnetic resonance imaging (MRI) of the knee is equal to or higher than that of 3T MRI by applying deep learning reconstruction (DLR).Proton density-weighted images of the right knee of 27 healthy volunteers were obtained by 3T and 1.5T MRI scanners using similar imaging parameters (21 for high resolution image and 6 for normal resolution image). Commercially available DLR was applied to the 1.5T images to obtain 1.5T/DLR images. The 3T and 1.5T/DLR images were compared subjectively for visibility of structures, image noise, artifacts, and overall diagnostic acceptability and objectively. One-way ANOVA and Friedman tests were used for the statistical analyses.For the high resolution images, all of the anatomical structures, except for bone, were depicted significantly better on the 1.5T/DLR compared with 3T images. Image noise scored statistically lower and overall diagnostic acceptability scored higher on the 1.5T/DLR images. The contrast between lateral meniscus and articular cartilage of the 1.5T/DLR images was significantly higher (5.89 ± 1.30 vs. 4.34 ± 0.87, P0.001), and also the contrast between medial meniscus and articular cartilage of the 1.5T/DLR images was significantly higher (5.12 ± 0.93 vs. 3.87 ± 0.56, P0.001). Similar image quality improvement by DLR was observed for the normal resolution images.The 1.5T/DLR images can achieve less noise, more precise visualization of the meniscus and ligaments, and higher overall image quality compared with the 3T images acquired using a similar protocol.

Background/Aims: We aimed to investigate incidence, characteristics, and possible risk factors of pancreatic cancer in patients under observation for hepatocellular carcinoma (HCC) because the association of hepatitis virus B infection and pancreatic cancer has been reported. Patients and Methods: We performed a retrospective cohort study in the Gastroenterology Department of a University Hospital in Japan between 2004 and 2012. A total of 1848 patients who underwent treatment for HCC were included at the initiation of treatment for HCC (mean follow-up period, 33.6 months). The patients received trimonthly radiological follow-ups. Newly developed cases of pancreatic cancer during follow-up for HCC were compared with that of an age- and sex-matched theoretical cohort from national statistics. Possible predisposing factors for pancreatic cancer related to HCC were assessed. Cumulative probabilities of developing a pancreatic cancer were compared using log-rank test. Results: About 13 of 1848 patients developed pancreatic cancer (mean follow-up period, 45.2 months). The risk ratio for all patients was 3.02 (log-rank test: P =0.01). Statistical analyses showed no effects of the following factors on the development of pancreatic cancer: age, sex, follow-up period, alcohol intake, laboratory data, presence of hepatitis virus, characteristics of HCC, type of treatment, number of radiological examinations, and cumulative effective dose. Conclusions: Increased incidence of pancreatic cancer was found in patients under observation for HCC in a relatively small cohort. HCC or other common underlying conditions might be a risk factor for development of pancreatic cancer.

A primary aortoduodenal fistula (PADF) has rarely been reported as a complication of testicular cancer. A 48-year-old Japanese male with relapsed retroperitoneal lymph node metastases received four courses of paclitaxel, ifosfamide, and cisplatin (TIP). On day 19 of the fourth cycle of TIP, he developed hematochezia and hypovolemic shock. Angiography confirmed the presence of a PADF, and we then deployed an endovascular stent graft in the aorta. Although the bleeding improved, the patient died of re-bleeding that developed 18 days later. It is important to recognize this severe complication in order to achieve its early diagnosis and optimal surgical intervention.

Japanese Diagnostic Reference Levels (DRLs) were released as "Japan DRLs 2015" from Japan Network for Research and Information on Medical Exposure (J-RIME) in June 2015. In "Japan DRLs 2015", DRLs in angiography and interventional procedures are set at a fluoroscopic dose rate of 20 mGy/min at the interventional reference point using a phantom. In order to achieve optimization with DRLs, then it need to be revised regularly. Therefore, we (research group to examine the effect of Japan DRLs 2015 and the necessity of additional items in angiography and vascular interventions) examined the effects of "Japan DRLs 2015" on angiography and interventional procedures. And we also investigated for DRLs revision in the future. As a result, it turned out that it is important to create DRLs in medical procedures that can be effectively used in clinical settings.

To evaluate the effects of the single-energy metal artifact reduction (SEMAR) algorithm on image quality of cerebral CT and CT angiography (CTA) for patients who underwent intracranial aneurysm coiling. Twenty patients underwent cerebral CT and CTA using a 320-detector row CT after intracranial aneurysm coiling. Images with and without application of the SEMAR algorithm (SEMAR CT and standard CT images, respectively) were reconstructed for each patient. The images were qualitatively assessed by two independent radiologists in a blinded manner for the depiction of anatomical structures around the coil, delineation of the arteries around the coil, and the depiction of the status of coiled aneurysms. Artifact strength was quantitatively assessed by measuring the standard deviation of attenuation values around the coil. The strength of artifacts measured in SEMAR CT images was significantly lower than that in standard CT images (25.7 ± 10.2 H.U. vs. 80.4 ± 67.2 H.U., p

Undifferentiated uterine sarcoma (UUS) is a high-grade sarcoma with no specific differentiation; however, it exhibits variable positivity for CD10 as an immunohistochemical marker of endometrial stroma, suggesting immunohistochemical differentiation into endometrial stroma. It has been reported that some low-grade endometrial stromal sarcoma pulmonary metastatic foci show cystic changes; however, whether pulmonary metastatic UUS foci are solid or cystic remains undescribed. A 63-year-old woman underwent a hysterectomy. The subsequent pathologic diagnosis was UUS. After the operation, she was treated with chemotherapy; however, pulmonary solitary shadow was radiologically detected. Eight months after the gynecologic operation, her pulmonary lesion was surgically resected. Pathologically, the lesion consisted of a cyst containing serous fluid with thick whitish wall composed of tumor cells, which led to the diagnosis of metastatsis of UUS. The cyst seemed to be formed via secondary degeneration. She remains healthy without recurrence 28 months after her first visit to our hospital.

To compare image quality characteristics of high-resolution computed tomography (HRCT) in the evaluation of interstitial lung disease using three different reconstruction methods: model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASIR), and filtered back projection (FBP).Eighty-nine consecutive patients with interstitial lung disease underwent standard-of-care chest CT with 64-row multi-detector CT. HRCT images were reconstructed in 0.625-mm contiguous axial slices using FBP, ASIR, and MBIR. Two radiologists independently assessed the images in a blinded manner for subjective image noise, streak artifacts, and visualization of normal and pathologic structures. Objective image noise was measured in the lung parenchyma. Spatial resolution was assessed by measuring the modulation transfer function (MTF).MBIR offered significantly lower objective image noise (22.24±4.53, P0.01 among all pairs, Student's t-test) compared with ASIR (39.76±7.41) and FBP (51.91±9.71). MTF (spatial resolution) was increased using MBIR compared with ASIR and FBP. MBIR showed improvements in visualization of normal and pathologic structures over ASIR and FBP, while ASIR was rated quite similarly to FBP. MBIR significantly improved subjective image noise (P0.01 among all pairs, the sign test), and streak artifacts (P0.01 each for MBIR vs. the other 2 image data sets).MBIR provides high-quality HRCT images for interstitial lung disease by reducing image noise and streak artifacts and improving spatial resolution compared with ASIR and FBP.

To investigate the radiological findings prognostic for the development of pancreatic adenocarcinoma in a cohort of patients with hepatocellular carcinoma, using multiphasic computed tomography (CT). A case–cohort study performed in a single university hospital. A database of patients who received hepatocellular carcinoma (HCC) treatment and trimonthly follow-up with four-phase dynamic CT was used (n = 1848). The cohort group was randomly extracted from the database (n = 103). The case group comprised nine patients from the database who developed pancreatic adenocarcinoma. The radiological findings were assessed during follow-up (average, 32 months). The incidence of pancreatic mass, inhomogeneous parenchyma, loss of fatty marbling and main pancreatic duct dilatation gradually increased from 4 to 13 months before the diagnosis of pancreatic adenocarcinoma. There was a significantly higher incidence of pancreatic mass, inhomogeneous parenchyma and loss of fatty marbling on CT at baseline (average, 34 months before diagnosis) in the case group compared with the cohort group (P values < 0.01) and those findings at baseline were revealed as prognostic factors for pancreatic carcinogenesis, respectively (log-rank test, P values < 0.001). Several radiological findings observed on multiphasic CT can assist in predicting pancreatic carcinogenesis well in advance. • Pancreatic findings in multiphasic CT help predict development of pancreatic adenocarcinoma. • Key findings are mass, inhomogeneous parenchyma and loss of fatty marbling. • Those findings were observed 34 months before confirmed diagnosis of adenocarcinoma. • Those findings were prognostic factors for pancreatic carcinogenesis.

This study aimed to investigate the frequency of fat retention in the bladder using postoperative computed tomography (CT) and the associated imaging or clinical findings in patients who underwent renal tumor surgery. We retrospectively reviewed postoperative CT images from 123 patients who underwent surgery for renal tumors (92 patients after partial nephrectomy and 31 after total nephrectomy). Furthermore, we evaluated preoperative tumor characteristics per an established standardized nephrometry scoring system (the R.E.N.A.L Nephrometry Score) for patients with partial nephrectomy. We also investigated whether collecting system repair occurred during surgery. Fat retention in the bladder was found in 5 patients (5.4%) after partial nephrectomy, but was not observed in any patients after total nephrectomy. No fat retention was seen immediately after partial nephrectomy (4–8 days), but occurred 2–15 months after the surgery. Subsequently, intravesical fat retention disappeared in 3 patients (8, 24, and 16 months later), and it persisted from 19–22 months after surgery in the remaining 2 patients. Collecting system repair occurred in 25 patients (27%) with partial nephrectomy. There was no statistically significant association between fat retention in the bladder and intraoperative collecting system repair (p = 0.12). The association with intravesical fat retention was not significant for either tumor size, distance to the collecting system, or the R.E.N.A.L. Nephrometry Score. Fat retention in the bladder after partial nephrectomy can be observed using CT, although it is relatively rare. It is clinically asymptomatic and disappears spontaneously in most cases.

We reviewed six cases suspected of having fish bones in the bile ducts on follow-up CT following pancreaticoduodenectomy. The period from surgery to CT examination in which fishbone migration was first suspected ranged from 282 to 1157 days with a median of 517 days. The fish bone in the bile duct disappeared in five out of six cases on subsequent CT. One case was complicated by hepatolithiasis, and the other five cases showed no biliary complications. In two cases, wandering of fish bones in the jejunal limb was observed on CT images before their migration into the bile ducts. Asymptomatic migration of fish bones to the bile ducts following pancreaticoduodenectomy is not rare, but serious complications can occasionally occur. Indications of intervention may be controversial in asymptomatic cases, but once fish bones are observed in the biliary tree or the jejunal limb, dietary instructions advising not to swallow fish bones may be a good option to prevent complications.

Objective To obtain information about the basic biliary anatomy of livers with right-sided ligamentum teres (RSLT). Summary of background data RSLT is a relatively rare anomaly with a reported incidence of 0.2–1.2%. Although the portal/hepatic venous and arterial anatomy of livers with RSLT has already been established, the biliary architecture of such livers remains unclear. Methods RSLT was detected in 48 patients during 12,071 consecutive image readings (0.4%). Of these patients, the cholangiograms of 46 patients were analyzed, and their intrahepatic biliary tree confluence patterns were classified. Results The following four unique biliary confluence patterns were identified in livers with RSLT: the symmetrical type (23/46), independent right lateral type (13/46), total left type (6/46), and total right type (1/46). Analyses of the portal and arterial branching patterns of these livers showed that there were no correlations between their biliary confluence patterns and their portal or arterial ramification patterns. Conclusion The basic biliary architecture of livers with RSLT was clarified. As the RSLT patients' anomalous biliary confluences differed from those seen in normal livers and were difficult to predict, preoperative cholangiography should be performed prior to complex hepatobiliary surgery involving livers with RSLT to ensure patient safety., Mini-Abstract: A review of 46 livers revealed 4 distinct biliary confluence patterns in livers exhibiting right-sided ligamentum teres (RSLT). As the biliary architecture is completely independent of the portal or arterial ramification patterns and difficult to predict, preoperative cholangiography should be performed to avoid incidental injuries to the biliary tree during major hepatectomy in livers with RSLT.

Solitary pulmonary capillary hemangioma (SPCH) is a rare disease, first described about autopsy cases in 2000 and about surgically resected cases in 2006. To date, only 9 surgically resected cases have been published in English. Here, we report 7 original cases with surgery (median age, 54 y; 4 females, 2 never-smokers). All patients were asymptomatic, and all nodules were detected by computed tomography (CT). The median (range) size of nodule was 11 (8 to 16) mm. Six of 7 cases showed the part-solid nodule appearance and 1 showed pure ground-glass nodule appearance in CT findings. The growth speed was very slow. No abnormal uptake of fluorine-18 fluorodeoxyglucose was observed in systemic positron-emission CT in all 3 cases we examined. No patients died from SPCH. Histologically, SPCH manifested as a solitary lesion composed of densely proliferating and dilated capillaries without cytologic atypia within the alveolar septa. In addition, capillaries of SPCH spread into the vascular lumen and involved the walls of bronchioles with protrusion into the lumen. Immunohistochemically, capillaries of SPCH uniformly expressed endothelial markers, such as CD31, CD34, and Factor VIII; and α-smooth muscle actin positive cells were also observed. To be accurately diagnosed, especially in intraoperative frozen sections, SPCH should be conceived as an entity that presents as a solitary nodule in CT. We propose that SPCH is an unrecognized benign capillary proliferative disease.

e18562 Background: Although patients with locoregional advanced maxillary sinus squamous cell carcinoma (MSSCC) are often treated with surgery followed by postoperative radiotherapy (RT), the cosmetic and functional outcomes are unsatisfactory. Moreover, the efficacy and safety of intra-arterial chemoradiotherapy are controversial. Methods: In this study, we investigated the efficacy and safety of low-dose cisplatin administration through the superficial temporal artery (STA) combined with definitive RT in patients with MSSCC. Between January 2009 and December 2018, 57 patients were administered weekly intra-arterial infusions of cisplatin (30–50 mg/m2/5h) through the STA with simultaneous intravenous infusions of sodium thiosulfate. Overall response rate (ORR), local progression-free survival (LFS), maxillectomy-free survival (MFS), progression-free survival (PFS), overall survival (OS), and safety were evaluated retrospectively. The impact of clinical factors on survival was investigated using the Cox proportional hazard models. Results: The median follow-up time was 44 months (range, 10–80 months). There were 4, 26, 23, and 4 patients with cT2, cT3, cT4a, and cT4b, respectively. All patients completed the planned treatment except for one patient who discontinued owing to facial palsy. The ORR was 98% with 51 and 5 patients having complete and partial responses, respectively. The 3-year LFS, PFS, and OS were 74%, 63%, and 81%, respectively for all patients and 100%, 81%, and 94%, respectively for 22 patients received 70 Gy irradiation. Notably, the 3-year MFS was 95% for all patients and 100% in patients received 70 Gy RT. The most common grade 3 or more toxic event was oral mucositis (22.8%). Additionally, 4 (7.0%) patients had catheter-related infections. Late grade 3 or more adverse events included optic nerve disorder (8.8%), osteonecrosis (7.0%), encephalopathy (1.8%), and increased creatinine levels (1.8%). Salvage surgery including hard palate resection and orbital exenteration were performed in 2 and 1 patients, respectively. No clinical factor was correlated with survival outcomes in our study cohort. Conclusions: Low-dose cisplatin through STA combined with RT, especially 70 Gy RT, was associated with promising tumor response, high organ preservation rate, and tolerable adverse events in MSSCC patients. Further prospective studies are warranted to compare these outcomes with primary surgery.

Background/objectives To demonstrate the utility of portal encasement as a criterion for early diagnosis of local recurrence (LR) after pancreaticoduodenectomy (PD) for pancreatic ductal adenocarcinoma (PDAC). Methods A total of 61 patients who underwent PD for PDAC were included in this retrospective study. Portal stenosis was evaluated by sequential postoperative computed tomography (CT) scans and correlated with disease recurrence. In addition to the conventional LR diagnostic criterion of a growing soft tissue mass, LR was evaluated using portal encasement as an additional diagnostic criterion. Portal encasement was defined as progressive stenosis of the portal system accompanied by a soft tissue mass, notwithstanding the enlargement of the mass. Results Benign portal stenosis was found on the first postoperative CT imaging in 16 patients. However, stenosis resolved a median of 81 days later in all but one patient whose stenosis was due to portal reconstruction during PD. Portal encasement could be distinguished from benign portal stenosis based on the timing of emergence of the portal stenosis. Portal encasement developed in 13 of the 19 patients with LR, including 6 patients in whom the finding of portal encasement led to the diagnosis of LR a median of 147 days earlier with our diagnostic criterion compared with the conventional diagnostic criteria. Conclusions Portal encasement should be considered as a promising diagnostic criterion for earlier diagnosis of LR after PD for PDAC.

Artifacts caused by metallic implants appear as dark and bright streaks at computed tomography (CT), which severely degrade the image quality and decrease the diagnostic value of the examination. When x-rays pass through a metal object, depending on its size and composition, different physical effects negatively affect the measurements in the detector, most notably the effects of photon starvation and beam hardening. To improve image quality and recover information about underlying structures, several artifact reduction methods have been introduced in modern CT systems. Projection-based metal artifact reduction (MAR) algorithms act in projection space and replace corrupted projections caused by metal with interpolation from neighboring uncorrupted projections. MAR algorithms primarily suppress artifacts that are due to photon starvation. The dual-energy CT technique is characterized by data acquisition at two different energy spectra. Dual-energy CT provides synthesized virtual monochromatic images at different photon energy (kiloelectron volt) levels, and virtual monochromatic images obtained at high kiloelectron volt levels are known to reduce the effects of beam hardening. In clinical practice, although MAR algorithms can be applied after image acquisition, the decision whether to apply dual-energy CT for the patient usually needs to be made before image acquisition. Radiologists should be more familiar with the clinical and technical features of each method and should be able to choose the optimal method according to the clinical situation.

Hepatocellular adenoma (HCA) is a rare primary benign tumor of the liver, which occurs predominantly in young and middle-aged women. Recently, the subclassification of HCA was proposed by the Bordeaux group. Subsequently, characteristic radiological and clinical features have been revealed in each HCA subtype. According to the previous literature, diffuse intratumoral fat deposition is a very common finding in hepatocyte nuclear factor 1α-negative HCA, but this finding has been reported in β-catenin-positive HCA in the literature for only one case. In this case report, we report the second case of β-catenin-positive HCA with MR imaging sign of diffuse intratumoral fat deposition, confirmed immunohistologically on the basis of a surgical specimen. In addition, our case showed hypovascularity and isointensity on the hepatobiliary phase which have been reported as characteristic findings in β-catenin-positive HCA. Diffuse intratumoral fat deposition can be observed in β-catenin-positive HCA, which has a greater probability of malignant transformation than other types of HCA.

The current data article provides behavioral and neuroimaging data for the research article ''Relatedness-dependent rapid development of brain activity in anterior temporal cortex during pair-association retrieval” (Jimura et al., 2016) [1]. Behavioral performance is provided in a table. Fig. 2 of the article is based on this table. Brain regions showing time effect are provided in a table. A statistical activation map for the time effect is shown in Fig. 3C of the article.

Arteriovenous fistula is any abnormal connection between an artery and a vein that bypasses the normal capillary bed and shunts arterial blood directly to the venous circulation. Uterine arteriovenous fistula (UAVF) is a potentially life-threatening condition by causing massive bleeding. This report describes a case of UAVF with massive hemorrhage. Prior to surgery, endovascular catheters for balloon occlusion were placed within bilateral uterine arteries. During surgery, the surgeon requested temporary balloon inflation for navigating and identifying inflow arteries. The balloon was kept inflated during the ligation of the vessels. Once ligation was completed, the balloon was deflated to confirm hemostasis. A total hysterectomy with removal of the UAVF was successfully achieved without significant blood loss. The fistula, in the resected specimen, was confirmed histologically with Elastica van Gieson staining. The preoperative placement of endovascular balloon-occlusion catheters should be considered when hysterectomy is planned where UAVF is located at the cardinal ligament.

To determine whether dose-reduced CT with model-based iterative image reconstruction (MBIR) is a useful tool with which to diagnose hepatic steatosis.This prospective clinical study approved by our Institutional Review Board included 103 (67 men and 36 women; mean age, 64.3 years) patients who provided written informed consent to undergo unenhanced CT. Images of reference-dose CT (RDCT) with filtered back projection (R-FBP) and low- and ultralow-dose CT (dose-length product; 24 and 9% of that of RDCT) with MBIR (L-MBIR and UL-MBIR) were reconstructed. Mean CT numbers of liver (CT[L]) and spleen (CT[S]), and quotient (CT[L/S]) of CT[L] and CT[S] were calculated from selected regions of interest. Bias and limits of agreement (LOA) of CT[L] and CT[L/S] in L-MBIR and UL-MBIR (vs. R-FBP) were assessed using Bland-Altman analyses. Diagnostic methods for hepatic steatosis of CT[L]48 Hounsfield units (HU) and CT[L/S]1.1 were applied to L-MBIR and UL-MBIR using R-FBP as the reference standard.Bias was larger for CT[L] in UL-MBIR than in L-MBIR (-3.18HU vs. -1.73HU). The LOA of CT[L/S] was larger for UL-MBIR than for L-MBIR (±0.425 vs. ±0.245) and outliers were identified in CT[L/S] of UL-MBIR. Accuracy (0.92-0.95) and the area under the receiver operating characteristics curve (0.976-0.992) were high for each method, but some were slightly lower in UL-MBIR than L-MBIR.Dose-reduced CT reconstructed with MBIR is applicable to diagnose hepatic steatosis, however, a low dose of radiation might be preferable.

BACKGROUND Preoperative administration of clear fluids by mouth has recently been endorsed as a way to improve postoperative outcomes. A carbohydrate-containing beverage supplemented with electrolytes or proteins may have additional benefits for patients' satisfaction. However, effects on gastric residual, nausea, and emesis and the effectiveness of these beverages for improving patients' hydration status have not been well defined. METHODS We evaluated changes in gastric volume over time by magnetic resonance imaging, as well as blood glucose levels, before and after administration of 500 mL oral rehydration solution (ORS) containing 1.8% glucose and electrolytes in 10 healthy volunteers. The same volume of an oral nutritional supplement (ONS) containing 18% glucose and supplemental arginine (545 mOsm/kg) was given to the same population using a crossover design. RESULTS The mean (median, 95% confidence interval) gastric fluid volume at 1 hour after oral ingestion was 55.0 (55.3, 39.0-70.9) mL in the ORS group, whereas 409.2 (410.9, 371.4-447.0) mL in the ONS group (P = 0.0002). The gastric fluid volume of all participants in the ORS group returned to

We aimed to compare the radiation dose and image quality of a minimal phase window centered at 77 % compared with a wide phase window in coronary CT angiography using the second-generation 320-row CT.Eighty patients with heart rate ≤75 bpm were retrospectively included. The first 40 patients underwent scanning with a wide phase window (65-85 %), while the last 40 patients underwent scanning with a minimal phase window centered at 77 %. Subjective image quality was graded using a 4-point scale (4 = excellent). Image noise and contrast-to-noise ratio at the proximal segments were also analyzed. The mean effective dose was derived from the dose length product multiplied by a chest conversion coefficient (κ = 0.014 mSv mGy(-1) cm(-1)).Minimal phase window scanning centered at 77 % reduced the radiation dose by 30 % compared with wide phase window scanning (1.7 vs 2.4 mSv, p = 0.0009). The subjective image quality showed no significant difference (3.75 vs 3.76, p = 0.77). No significant difference was observed in the image noise, CT number, and contrast-to-noise ratio.Radiation dose could be reduced while maintaining image quality by use of a minimal phase window centered at 77 % compared with a wide phase window in coronary CT angiography using the second generation 320-row CT.

To determine whether superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging could demonstrate signal recovery delay in irradiated areas of rat livers. We also investigated the relationship between MR imaging and histological findings.Twelve rats received 20 μmol iron/kg of SPIO followed by X-irradiation to the right upper abdomen 4 h later. Radiation doses were 0, 50 and 70 Gy. Hepatic signals were assessed on unenhanced T 2 (*) -weighted images for up to 7 days using a 9.4-Tesla scanner. The livers were excised on day 7 and examined histologically.Normalized relative signal intensity of 70 Gy-irradiated right liver lobe (2.36 ± 0.22) and 50 Gy-irradiated right liver lobe (2.37 ± 0.46) was significantly lower than that of the non-irradiated right liver lobe (4.04 ± 0.28) on day 7, respectively (p 0.05). Pearson product-moment correlation coefficient between relative intensity of the liver and the number of hepatic iron deposits was -0.588 (p 0.01).Superparamagnetic iron oxide-enhanced MR imaging could demonstrate signal recovery delay in irradiated areas of rat livers. It seems that the signal recovery delay in irradiated areas was due to SPIO-derived iron deposition. Hepatic signal recovery could be a novel diagnostic marker for delineation of irradiated areas.

Rationale Budd-Chiari syndrome (BCS), which causes congestive hepatopathy and aggravates cirrhosis, is typically treated by interventional angioplasty to ameliorate blood flow. X-ray venography is useful for the evaluation of inferior vena cava (IVC) stenosis and determination of treatment timing, but it is invasive and thus unsuitable for repeated examinations. The development of a simple method for the prediction of IVC stenosis would reduce the burden on patients with BCS. Patient concerns We report here our experience of 2 patients with BCS who underwent percutaneous transluminal angioplasty (PTA). The first patient was a 39-year-old male who underwent PTA to expand his stenotic IVC. The second patient was a 19-year-old male who underwent PTA 3 times due to restenosis of his IVC. Diagnoses Both patients were diagnosed with BCS with severe obstruction of the IVC. Interventions We evaluated the hepatic vein (HV) waveform by Doppler ultrasonography and measured liver stiffness (LS) using transient elastography (TE) before and after PTA. Outcomes In case 1, the phasic oscillation of the HV waveform recovered and the LS value decreased after PTA. Both improvements were maintained for ∼3 years, reflecting the long-term patency of the IVC. In case 2, the HV waveform and the LS value improved temporarily after PTA, but then deteriorated gradually. Monitoring of the HV waveform and LS value allowed retreatment prior to total occlusion of the IVC and abrogated the risk of intravascular needle puncture. Lessons Monitoring of the HV waveform and the LS value enables safe management of patients with BCS who may require PTA.

To investigate the effect of saline flush on coronary CT angiography of proximal, middle, and distal coronary artery segments, using 320-row CT, and to compare two injection duration protocols as to amount of contrast in the right heart chambers.This retrospective study was approved by the local ethics committee, and the requirement for informed consent to participate in this study was waived. The final study group included 108 patients who underwent coronary CT angiography. The first 36 patients received contrast medium without saline flush (group 1); the next 36 patients received contrast medium for 14s and saline flush (group 2); the last 36 patients received contrast medium for 12s and saline flush (group 3). The CT number, noise, contrast-to-noise ratio (CNR), and number of segments with a CT number greater than 325 Hounsfield units (HU) were recorded for proximal, middle, and distal segments.The CT numbers and the CNR in groups 2 and 3 were significantly higher than that in group 1 (p0.005); the difference between groups 2 and 3 was not significant. The proportion of segments greater than 325HU improved with saline flush (p0.05), with a larger improvement in the distal segments.Saline flush improves enhancement and CNR of coronary arteries, particularly of distal segments, in coronary CT angiography using 320-row CT. An average contrast medium injection of 44mL was feasible using a saline flush.

The purpose of this article is to noninvasively visualize intrabiliary bile movement using an MRI spin-labeling technique and administration of water, full-fat milk, and negative contrast agent as stimuli for bile excretion.Six healthy volunteers underwent three studies with each of three oral liquid agents (water, full-fat milk, and manganese chloride solution) for a total of 18 MRI studies. Oblique-coronal T2-weighted images of the common bile duct were acquired at an inversion time of 1500 milliseconds after pulse labeling using a spin-labeling technique with an inversion pulse, repeated at intervals of 22 seconds. Bile flow rate was measured before and for 50 minutes after administration of the oral liquid agents, and its correlation with the change in gallbladder volume was assessed.Both anterograde and retrograde intermittent bile movements were successfully visualized in the common bile duct. The summation of excreted bile volume calculated from spin-labeled images correlated significantly with a decrease in gallbladder volume (p = 0.011). Milk stimulated significantly prolonged bile flow; flow was momentary with manganese chloride and mild with water; however, gallbladder volume decreased only in milk studies (p = 0.003). Biliary flow early after oral intake correlated significantly with gallbladder contractility at 50 minutes after oral intake (p = 0.049).A new method for visualizing intrabiliary bile movement in semi-real time (22-second time resolution) using an MRI spin-labeling technique was proposed. Bile was shown to be excreted in a to-and-fro type of movement. Administration of water and negative contrast agent may induce temporary bile excretion.

To assess the image quality and radiation dose reduction in various heart rates in coronary CT angiography using the second-generation 320-detector row CT compared with the first-generation CT. Ninety-six patients were retrospectively included. The first 48 patients underwent coronary CT angiography with the first-generation 320-detector row CT, while the last 48 patients underwent with the second-generation CT. Subjective image quality was graded using a 4-point scale (4, excellent; 1, unable to evaluate). Image noise and contrast-to-noise ratio were also analyzed. Subgroup analysis was performed based on the heart rate. The mean effective dose was derived from the dose length product multiplied by a conversion coefficient for the chest (κ = 0.014 mSv × mGy(-1) × cm(-1)). The overall subjective image quality score showed no significant difference (3.66 vs 3.69, respectively, p = 0.25). The image quality score of the second-generation group tended to be higher than that of the first-generation group in the 66- to 75-bpm subgroup (3.36 vs 3.53, respectively, p = 0.07). No significant difference was observed in image noise and contrast-to-noise ratio. The overall radiation dose reduced by 24 % (3.3 vs 2.5 mSv, respectively, p = 0.03), and the reduction was substantial in patients with higher heart rate (66- to 75-bpm, 4.3 vs 2.2 mSv, respectively, p = 0.009; >75 bpm, 8.2 vs 3.7 mSv, respectively, p = 0.005). The second-generation 320-detector row CT could maintain the image quality while reducing the radiation dose in coronary CT angiography. The dose reduction was larger in patients with higher heart rate.

Purpose The purpose of this study was to evaluate whether model-based iterative reconstruction (MBIR) enables dose reduction over adaptive iterative reconstruction (ASIR) while maintaining diagnostic performance. Methods In this institutional review board-approved and Health Insurance Portability and Accountability Act-compliant study, 59 patients (mean [SD] age, 64.7 [13.4] years) gave informed consent to undergo reference-, low-, and ultralow-dose chest computed tomography (CT) with 64-row multidetector CT. The reference- and low-dose CT involved the use of automatic tube current modulation with fixed noise indices (31.5 and 70.44 at 0.625 mm, respectively) and were reconstructed with 50% ASIR-filtered back projection blending. The ultralow-dose CT was acquired with a fixed tube current-time product of 5 mA s and reconstructed with MBIR. Two radiologists evaluated 2.5- and 0.625-mm-slice-thick axial images from low-dose ASIR and ultralow-dose MBIR, recorded the pattern of each nodule candidate, and assigned each a confidence score. A reference standard was established by a consensus panel of 2 different radiologists, who identified 84 noncalcified nodules with diameters of 4 mm or greater on reference-dose ASIR (ground-glass opacity, n = 18; partly solid, n = 11; solid, n = 55). Sensitivity in nodule detection was assessed using the McNemar test. Jackknife alternative free-response receiver operating characteristic (JAFROC) analysis was applied to assess the results including confidence scores. Results Compared with the low-dose CT, a 78.1% decrease in dose-length product was seen with the ultralow-dose CT. No significant differences were observed between the low-dose ASIR and the ultralow-dose MBIR for overall nodule detection in sensitivity (P = 0.48-0.69) or the JAFROC analysis (P = 0.57). Likewise, no significant differences were seen for ground-glass opacity, partly solid, or solid nodule detection in sensitivity (P = 0.08-0.65) or the JAFROC analysis (P = 0.21-0.90). Conclusions Model-based iterative reconstruction enables nearly an 80% reduction in radiation dose for chest CT from a low-dose level to an ultralow-dose level, without affecting nodule detectability.

To evaluate the impact on image quality of three different image reconstruction techniques in the cervicothoracic region: model-based iterative reconstruction (MBIR), adaptive statistical iterative reconstruction (ASIR), and filtered back projection (FBP).Forty-four patients underwent unenhanced standard-of-care clinical computed tomography (CT) examinations which included the cervicothoracic region with a 64-row multidetector CT scanner. Images were reconstructed with FBP, 50% ASIR-FBP blending (ASIR50), and MBIR. Two radiologists assessed the cervicothoracic region in a blinded manner for streak artifacts, pixilated blotchy appearances, critical reproduction of visually sharp anatomical structures (thyroid gland, common carotid artery, and esophagus), and overall diagnostic acceptability. Objective image noise was measured in the internal jugular vein. Data were analyzed using the sign test and pair-wise Student's t-test.MBIR images had significant lower quantitative image noise (8.88 ± 1.32) compared to ASIR images (18.63 ± 4.19, P0.01) and FBP images (26.52 ± 5.8, P0.01). Significant improvements in streak artifacts of the cervicothoracic region were observed with the use of MBIR (P0.001 each for MBIR vs. the other two image data sets for both readers), while no significant difference was observed between ASIR and FBP (P0.9 for ASIR vs. FBP for both readers). MBIR images were all diagnostically acceptable. Unique features of MBIR images included pixilated blotchy appearances, which did not adversely affect diagnostic acceptability.MBIR significantly improves image noise and streak artifacts of the cervicothoracic region over ASIR and FBP. MBIR is expected to enhance the value of CT examinations for areas where image noise and streak artifacts are problematic.

Unicentric Castleman’s disease is a rare, benign lymphoproliferative disorder that is curable with surgical resection. However, significant bleeding often occurs during surgery because of tumor hypervascularity. We herein present a case of hyaline-vascular-type mediastinal unicentric Castleman’s disease, successfully resected using video-assisted thoracoscopic surgery with preoperative embolization. In the present case, tumor hypervascularity and feeding vessels were revealed by computed tomography (CT), which led us to perform preoperative angiography and embolization to the tumor feeding arteries to reduce intraoperative bleeding. Castleman’s disease should be considered in the differential diagnosis of hypervascular mediastinal tumors. Tumor vascularity should be assessed prior to surgery, and preoperative embolization should be considered.

The orbitofrontal cortex (OFC) is involved in cognitive functions, and is also closely related to autonomic functions. The OFC is densely connected with the hypothalamus, a heterogeneous structure controlling autonomic functions that can be divided into two major parts: the lateral and the medial. Resting-state functional connectivity has allowed us to parcellate the cerebral cortex into putative functional areas based on the changes in the spatial pattern of connectivity in the cerebral cortex when a seed point is moved from one voxel to another. In the present high spatial-resolution fMRI study, we investigate the connectivity-based organization of the OFC with reference to the hypothalamus. The OFC was parcellated using resting-state functional connectivity in an individual subject approach, and then the functional connectivity was examined between the parcellated areas in the OFC and the lateral/medial hypothalamus. We found a functional double dissociation in the OFC: the lateral OFC (the lateral orbital gyrus) was more likely connected with the lateral hypothalamus, whereas the medial OFC (the medial orbital and rectal gyri) was more likely connected with the medial hypothalamus. These results demonstrate the fundamental heterogeneity of the OFC, and suggest a potential neural basis of the OFC–hypothalamic functional interaction.

Objective.To compare the image quality of coronary computed tomography angiography (CCTA) acquired under two conditions: 75% fixed as the acquisition window center (Group 75%) and the diagnostic phase for calcium scoring scan as the center (CS; Group CS).Methods.320-row cardiac CT with a minimal acquisition window (scanned using “Target CTA” mode) was performed on 81 patients. In Group 75% (n= 40), CS was obtained and reconstructed at 75% and the center of the CCTA acquisition window was set at 75%. In Group CS (n= 41), CS was obtained at 75% and the diagnostic phase showing minimal artifacts was applied as the center of the CCTA acquisition window. Image quality was evaluated using a four-point scale (4-excellent) and the mean scores were compared between groups.Results.The CCTA scan diagnostic phase occurred significantly earlier in CS (75.7 ± 3.2% vs. 73.6 ± 4.5% for Groups 75% and CS, resp.,p= 0.013). The mean Group CS image quality score (3.58 ± 0.63) was also higher than that for Group 75% (3.19 ± 0.66,p< 0.0001).Conclusions.The image quality of CCTA in Target CTA mode was significantly better when the center of acquisition window is adjusted using CS.

Purpose To study the three-dimensional movement of internal tumor bed fiducial and breast skin markers, using 320-multislice computed tomography (CT); and to analyze intrafractional errors for breast cancer patients undergoing breast irradiation. Methods and Materials This study examined 280 markers on the skin of the breast (200 markers) and on the primary tumor bed (80 markers) of 20 patients treated by external-beam photon radiotherapy. Motion assessment was analyzed in 41 respiratory phases during 20 s of cine CT in the radiotherapy position. To assess intrafractional errors resulting from respiratory motion, four-dimensional CT scans were acquired for 20 patients. Results Motion in the anterior–posterior (A/P) and superior–inferior (S/I) directions showed a strong correlation (|r| > 0.7) with the respiratory curve for most markers (79% and 70%, respectively). The average marker displacements between maximum and minimum value during 20 s for the 200 breast skin metal markers were 1.1 ± 0.3 mm, 2.1 ± 0.6 mm, and 1.6 ± 0.4 mm in the left–right, A/P, and S/I directions, respectively. For the 80 tumor bed clips, displacements were 0.9 ± 0.2 mm in left–right, 1.7 ± 0.5 mm in A/P, and 1.1 ± 0.3 mm in S/I. There was no significant difference in the motion between breast quadrant regions or between the primary site and the other regions. Conclusions Motion in primary breast tumors was evaluated with 320-multislice CT. Very little change was detected during individual radiation treatment fractions.

Purpose Recurrence of hepatocellular carcinoma (HCC) is very common even after curative resection or ablation. This retrospective study compared the radiologic features of recurrent HCC seen by computed tomography (CT) to evaluate our empirical protocol of CT surveillance using 4-month intervals. Materials and Methods A total of 113 patients who were diagnosed with a first HCC recurrence after radiofrequency (RF) ablation between January 2005 and December 2006 were enrolled at a single center. Definite HCC was defined as hyperattenuation in the arterial phase with washout in the portal venous phase, and a diagnosis of naive and recurrent HCC was based on dynamic CT findings. Recurrent nodules were classified according to the enhancement patterns of previous CT images. The treatment modality for recurrent HCC and survival were evaluated. Results One hundred seventy-seven nodules were diagnosed as recurrent HCC: 31 (17.5%) had already been diagnosed on previous CT images as typical HCC, 72 (40.6%) had arterial hypervascularity without washout in the portal venous phase, 21 (11.9%) showed portal venous phase washout without arterial hypervascularity, and no lesions were noted in the remaining 49 (27.7%). Tumor size at recurrence was smaller than 2 cm in diameter in 98 (86.7%) cases. One hundred four patients were treated for recurrent HCC with RF ablation. The 5-year survival rate after recurrence was 49.8%. There was no significant difference in survival among groups divided by the enhancement pattern on the previous CT examination. Conclusions Dynamic CT in 4-month intervals is an acceptable recurrence-monitoring strategy because it detects most recurrent nodules at a stage at which RF ablation is still feasible.

We compared diagnostic ability for detecting hepatic metastases between gadolinium ethoxy benzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) on a 1.5-T system, and determined whether DWI is necessary in Gd-EOB-DTPA-enhanced MRI for diagnosing colorectal liver metastases.We assessed 29 consecutive prospectively enrolled patients with suspected metachronous colorectal liver metastases; all patients underwent surgery and had preoperative Gd-EOB-DTPA-enhanced MRI. Overall detection rate, sensitivity for detecting metastases and benign lesions, positive predictive value, and diagnostic accuracy (Az value) were compared among three image sets [unenhanced MRI (DWI set), Gd-EOB-DTPA-enhanced MRI excluding DWI (EOB set), and combined set].Gd-EOB-DTPA-enhanced MRI yielded better overall detection rate (77.8-79.0 %) and sensitivity (87.1-89.4 %) for detecting metastases than the DWI set (55.9 % and 64.7 %, respectively) for one observer (P0.001). No statistically significant difference was seen between the EOB and combined sets, although several metastases were newly detected on additional DWI.Gd-EOB-DTPA-enhanced MRI yielded a better overall detection rate and higher sensitivity for detecting metastases compared with unenhanced MRI. Additional DWI may be able to reduce oversight of lesions in Gd-EOB-DTPA-enhanced 1.5-T MRI for detecting colorectal liver metastases.

To prospectively evaluate dose reduction and image quality characteristics of chest CT reconstructed with model-based iterative reconstruction (MBIR) compared with adaptive statistical iterative reconstruction (ASIR).One hundred patients underwent reference-dose and low-dose unenhanced chest CT with 64-row multidetector CT. Images were reconstructed with 50 % ASIR-filtered back projection blending (ASIR50) for reference-dose CT, and with ASIR50 and MBIR for low-dose CT. Two radiologists assessed the images in a blinded manner for subjective image noise, artefacts and diagnostic acceptability. Objective image noise was measured in the lung parenchyma. Data were analysed using the sign test and pair-wise Student's t-test.Compared with reference-dose CT, there was a 79.0 % decrease in dose-length product with low-dose CT. Low-dose MBIR images had significantly lower objective image noise (16.93 ± 3.00) than low-dose ASIR (49.24 ± 9.11, P0.01) and reference-dose ASIR images (24.93 ± 4.65, P0.01). Low-dose MBIR images were all diagnostically acceptable. Unique features of low-dose MBIR images included motion artefacts and pixellated blotchy appearances, which did not adversely affect diagnostic acceptability.Diagnostically acceptable chest CT images acquired with nearly 80 % less radiation can be obtained using MBIR. MBIR shows greater potential than ASIR for providing diagnostically acceptable low-dose CT images without severely compromising image quality.• Model-based iterative reconstruction (MBIR) creates high-quality low-dose CT images. • MBIR significantly improves image noise and artefacts over adaptive statistical iterative techniques. • MBIR shows greater potential than ASIR for diagnostically acceptable low-dose CT. • The prolonged processing time of MBIR may currently limit its routine use in clinical practice.

Objectives To investigate the relationship between cardiac output, end diastolic volume and the contrast enhancement in coronary CT angiography using 320-detector CT. Materials and methods A total of 38 patients underwent coronary CT angiography by using a 320-detector CT scanner (detector configuration, 320 × 0.5 mm). The attenuation value of the ascending aorta at the level of the orifice of the left main trunk was measured. The cardiac output (CO), end diastolic volume (EDV) and stroke volume (SV) were measured by echocardiography. The EDV was normalized to the body surface area (BSA). The total blood volume injected from the left ventricle from the beginning of the contrast agent injection to the time of image acquisition was determined to be the total injected blood volume (TIV), which is a product of SV and the number of heart beats from the initiation of contrast agent injection to the scan. Results There was a negative correlation between the attenuation of the ascending aorta and CO (r = −0.44, P = 0.0053). However, the negative correlation between the attenuation of the ascending aorta and TIV was stronger (r = −0.52, P = 0.0007). There was a negative correlation between the attenuation of the ascending aorta and EDV/BSA (r = −0.45, P = 0.0039). Conclusion In 320-detector CT, contrast enhancement in CCTA with a lesser amount of contrast medium decreases when cardiac output is high. Patients with larger EDV/BSA may also show decreased attenuation.

We evaluated the sensitivity and specificity of post-vascular phase (Kupffer imaging) by contrast-enhanced ultrasonography (CEUS) using perflubutane microbubbles (Sonazoid) in comparison with conventional B-mode ultrasonography (US) for the detection of hepatocellular carcinoma (HCC) nodules.A total of 100 treatment-naïve HCC patients admitted at our hospital between December 2007 and June 2009 were consecutively enrolled. The sensitivity and specificity of conventional and contrast-enhanced US were evaluated on a liver segment basis using dynamic CT as a reference standard. Movie files of conventional and enhanced US were stored separately for each segment (e.g., lateral, medial, anterior, and posterior) and reviewed randomly by two blinded readers.A total of 138 HCC nodules (mean diameter 20.3 mm) were detected in 123 of 400 segments. Detection sensitivity of B-mode US was 0.837 for reader A and 0.846 for reader B, and that of CEUS was 0.732 for reader A and 0.831 for reader B. Specificity of B-mode US was 0.902 for reader A and 0.949 for reader B, and that of CEUS was 0.986 for reader A and 0.978 for reader B. CEUS false positives were mainly due to misidentification of hepatic cysts. A significant proportion of false-negative nodules are hyperechoic in B-mode US, likely because echogenicity hampers visualization of the defect in Kupffer imaging.Kupffer imaging by CEUS with Sonazoid showed very high specificity but rather mediocre sensitivity for HCC detection. CEUS is highly suitable for confirmatory diagnosis of HCC; however, caution should be exercised in reaching a diagnosis based only on CEUS.