Showing papers in "Japanese Journal of Radiology in 2018"

Deep learning with convolutional neural network in radiology

Abstract: Deep learning with a convolutional neural network (CNN) is gaining attention recently for its high performance in image recognition. Images themselves can be utilized in a learning process with this technique, and feature extraction in advance of the learning process is not required. Important features can be automatically learned. Thanks to the development of hardware and software in addition to techniques regarding deep learning, application of this technique to radiological images for predicting clinically useful information, such as the detection and the evaluation of lesions, etc., are beginning to be investigated. This article illustrates basic technical knowledge regarding deep learning with CNNs along the actual course (collecting data, implementing CNNs, and training and testing phases). Pitfalls regarding this technique and how to manage them are also illustrated. We also described some advanced topics of deep learning, results of recent clinical studies, and the future directions of clinical application of deep learning techniques.

Denoising of 3D magnetic resonance images with multi-channel residual learning of convolutional neural network.

Abstract: To test if the proposed deep learning based denoising method denoising convolutional neural networks (DnCNN) with residual learning and multi-channel strategy can denoise three dimensional MR images with Rician noise robustly. Multi-channel DnCNN (MCDnCNN) method with two training strategies was developed to denoise MR images with and without a specific noise level, respectively. To evaluate our method, three datasets from two public data sources of IXI dataset and Brainweb, including T1 weighted MR images acquired at 1.5 and 3 T as well as MR images simulated with a widely used MR simulator, were randomly selected and artificially added with different noise levels ranging from 1 to 15%. For comparison, four other state-of-the-art denoising methods were also tested using these datasets. In terms of the highest peak-signal-to-noise-ratio and global of structure similarity index, our proposed MCDnCNN model for a specific noise level showed the most robust denoising performance in all three datasets. Next to that, our general noise-applicable model also performed better than the rest four methods in two datasets. Furthermore, our training model showed good general applicability. Our proposed MCDnCNN model has been demonstrated to robustly denoise three dimensional MR images with Rician noise.

Pathology and images of radiation-induced hepatitis: a review article

Abstract: Recent advances in highly conformal radiotherapies greatly extend the indications for radiotherapy of liver tumors. However, because of poor tolerance to hepatic radiation, estimation of the intensity of irradiation of the liver is important, particularly for a cirrhotic liver. Knowledge of radiation-induced hepatitis is important for understanding how to optimize hepatic radiation therapy. Pathological changes of the irradiated liver, which include perivenular fibrosis, sinusoidal obstruction, and damage to Kupffer cells and hepatocytes, can be visualized using clinical imaging techniques. This review article discusses and illustrates the pathological and radiological changes of hepatic tumors and the surrounding parenchyma of the irradiated liver.

Radiofrequency ablation versus cryoablation for T1b renal cell carcinoma: a multi-center study

Abstract: To compare the clinical outcomes between radiofrequency ablation (RFA) and cryoablation for the treatment of clinical T1b (cT1b) renal cell carcinoma (RCC). The data of 46 patients [(39 men and 7 women, median age; 73 years, range 39–87 years)] were gathered from 3 institutions. RFA and cryoablation were performed on 23 patients each. The median number of ablation needle was 2 (range 1–4) and 4 (range 3–5, p 0.99). There was no significant difference between local tumor progression rate after RFA and cryoablation [3/21 (14%) vs. 2/23 (9%); P = 0.66]. The 5-year overall survival rates were comparable between RFA and cryoablation (78 vs. 82%; P =0.82). Other than primary technique efficacy, the clinical outcomes between RFA and cryoablation were similar in patients with cT1b RCC.

Evaluation of adaptive radiotherapy (ART) by use of replanning the tumor bed boost with repeated computed tomography (CT) simulation after whole breast irradiation (WBI) for breast cancer patients having clinically evident seroma

Abstract: The aim of this study is to evaluate adaptive radiotherapy (ART) by use of replanning the tumor bed boost with repeated computed tomography (CT) simulation after whole breast irradiation (WBI) for breast cancer patients having clinically evident seroma. Forty-eight patients with clinically evident seroma at the time of planning CT simulation for WBI were included. Two RT treatment plannings were generated for each patient based on the initial CT simulation and tumor bed boost CT simulation to assess seroma and boost target volume (BTV) changes during WBI. Also, dosimetric impact of ART was analyzed by comparative evaluation of critical organ doses in both RT treatment plannings. Median time interval between the two CT simulations was 35 days. Statistically significant reduction was detected in seroma volume and BTV during the conventionally fractionated WBI course along with statistically significant reduction in critical organ doses with ART (p < 0.0001). Our data suggest significant benefit of ART by use of replanning the tumor bed boost with repeated CT simulation after WBI for patients with clinically evident seroma.

Imaging features of benign mass lesions in the nasal cavity and paranasal sinuses according to the 2017 WHO classification

Abstract: The World Health Organization (WHO) 2017 classification of head and neck tumors has been just published and has reorganized tumors of the nasal cavity and paranasal sinuses. In this classification, three new entities (seromucinous hamartoma, NUT carcinoma, and biphenotypic sinonasal sarcoma) were included, while the total number of tumors has been reduced by excluding tumors if they did not occur exclusively or predominantly in this region. Among these entities, benign tumors were classified as sinonasal papillomas, respiratory epithelial lesions, salivary gland tumors, benign soft tissue tumors, or other tumors. In contrast, inflammatory diseases often show tumor-like appearances. The imaging features of these benign tumors and tumor-like inflammatory diseases often resemble malignant tumors, and some benign lesions should be given attention in the follow-up period and before surgery to avoid recurrence, malignant transformation, or massive bleeding. Understanding the CT and MR imaging features of various benign mass lesions is clinically important for appropriate therapy. The purpose of this article is to describe the clinical characteristics and imaging features of each of clinically important nasal and paranasal benign mass lesions, as classified according to the WHO 2017 classification of head and neck tumors, along with some inflammatory diseases.

Dual energy computed tomography for the head.

Abstract: Dual energy CT (DECT) is a promising technology that provides better diagnostic accuracy in several brain diseases. DECT can generate various types of CT images from a single acquisition data set at high kV and low kV based on material decomposition algorithms. The two-material decomposition algorithm can separate bone/calcification from iodine accurately. The three-material decomposition algorithm can generate a virtual non-contrast image, which helps to identify conditions such as brain hemorrhage. A virtual monochromatic image has the potential to eliminate metal artifacts by reducing beam-hardening effects. DECT also enables exploration of advanced imaging to make diagnosis easier. One such novel application of DECT is the X-Map, which helps to visualize ischemic stroke in the brain without using iodine contrast medium.

Multimodality imaging in secondary postpartum or postabortion hemorrhage: retained products of conception and related conditions.

Abstract: Secondary postpartum hemorrhage (PPH) and postabortion hemorrhage are rare complications. Retained products of conception (RPOC) is among the most common causes of both secondary PPH and postabortion hemorrhage. Other less common causes of secondary PPH are uterine vascular abnormalities such as arteriovenous malformations and pseudoaneurysms. These are usually related to a history of a procedure such as dilation and curettage or cesarean delivery. Subinvolution of the placental site is an idiopathic cause of secondary PPH; this condition may be underrecognized and therefore could have a higher incidence than currently reported. Gestational trophoblastic disease is rare but commonly presents as secondary PPH and resembles RPOC in radiologic appearance. The first-line imaging modality for secondary PPH is ultrasound, but computed tomography and magnetic resonance imaging may be used if the ultrasound findings are indeterminate. Angiography is an important tool for the definitive diagnosis of uterine vascular abnormalities. Appropriate management requires radiologists to be familiar with the multimodality imaging features of secondary PPH or postabortion hemorrhage.

Diagnostic performance of 18 F-FDG PET/CT and whole-body MRI before and early after treatment of multiple myeloma: a prospective comparative study.

Abstract: To determine the diagnostic accuracy of WB-MRI and 18F-FDG PET/CT in detecting infiltration pattern, disease activity, and response to treatment in patients with multiple myeloma (MM). Fifty-six patients with confirmed MM were included in the present study for pre-treatment evaluation. Among these individuals, 22 patients were available for the post-treatment evaluation of response to therapy. All patients were imaged with both WB-MRI and 18F-FDG PET/CT. All radiographic findings of infiltration pattern, disease activity, and response to therapy were compared. The diagnostic performance of both modalities was estimated using bone marrow aspirate and biopsy as the reference test. For detection of active myelomatous tissue at diagnosis, WB-MRI achieved higher sensitivity (94%) than 18F-FDG PET/CT (75%) (p = 0.0039), whereas both modalities achieved the same specificity (80%). For detection of residual myelomatous tissue after treatment, 18F-FDG PET/CT achieved higher specificity (86%) than WB-MRI (43%) (p = 0.0081), whereas both modalities achieved the same sensitivity (75%). WB-MRI is more sensitive than 18F-FDG PET/CT in the diagnosis of MM before treatment; however, 18F-FDG PET/CT is more specific than WB-MRI in detecting residual involvement in treated patients.

HRCT texture analysis for pure or part-solid ground-glass nodules: distinguishability of adenocarcinoma in situ or minimally invasive adenocarcinoma from invasive adenocarcinoma.

Abstract: To distinguish between adenocarcinoma in situ (AIS)–minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) showing pure or part-solid ground-glass nodules (GGNs) by high-resolution computed tomography (HRCT) texture analysis. This retrospective study included 101 consecutive patients with 115 pure or part-solid GGNs ≤ 3 cm diameter, which were surgically resected and pathologically diagnosed with AIS, MIA, or IAC (48 AIS–MIA and 67 IAC) between April 2011 and March 2015. Each tumor was manually segmented on axial CT images, and the following texture features were calculated: volume, mass, mean CT value, variance, skewness, kurtosis, entropy, uniformity, and percentile CT numbers (10th, 25th, 50th, 75th, 90th, 95th percentiles). The differences between AIS–MIA and IAC were statistically evaluated using univariate, multivariate, and receiver operating characteristic analysis. Compared with IAC, AIS–MIA had significantly greater skewness, kurtosis, and uniformity, whereas in the other parameters, AIS–MIA demonstrated significantly lower values than those of IAC. Multivariate analysis revealed that independent differentiators were the 90th percentile CT numbers (P < 0.001) and entropy (P = 0.005) with an excellent accuracy (area under the curve, 0.90). The 90th percentile CT numbers and entropy can accurately distinguish AIS–MIA from IAC.

Pleomorphic adenoma of salivary glands: common and uncommon CT and MR imaging features

Abstract: Pleomorphic adenoma (PA) is the most common salivary gland tumor and is characterized by cytomorphological and architectural diversity. On CT and MR images, PAs are shown as well-defined lesions occasionally accompanied by characteristic lobulated contours. On T2-weighted images, typical PAs show marked hyperintensity, which reflects the abundant myxochondroid stroma, with a hypointense rim indicating the fibrous capsule. However, intratumoral signal intensity varies according to the cellular density, proportion of epithelial and stromal components, and type of stromal components. In addition, a variety of secondary histological changes, including fibrosis, lipometaplasia, ossification, cystic degeneration, and infarction, occur rarely in PAs; therefore, they are associated with difficulty in differential diagnosis from other salivary gland tumors. This review article describes the common and uncommon CT and MR imaging features of PA of the salivary glands.

Global and Japanese regional variations in radiologist potential workload for computed tomography and magnetic resonance imaging examinations

Abstract: In Results of Abstract, the first sentence should read as: The radiologist potential workload in Japan was 2.78-4.17 times higher than those in other countries.

Comparison of detectability of breast cancer by abbreviated breast MRI based on diffusion-weighted images and postcontrast MRI

Abstract: To compare the detectability of unenhanced abbreviated magnetic resonance imaging (MRI) based on diffusion-weighted imaging (DWI) and abbreviated postcontrast MRI for breast cancer. The study population consisted of 87 patients undergoing breast MRI between December 2016 and March 2017 in a clinical setting. All breast MRIs were performed using a 1.5-T MRI scanner with a 16-channel breast radiofrequency coil. The abbreviated protocols based on DWI (AP1) and postcontrast MRI (AP2) were assessed independently by two radiologists. Sensitivity and specificity were calculated. Receiver operating characteristic analysis was performed and the areas under the curves (AUCs) were compared between AP1 and AP2. The study included 87 patients with 89 breast cancer lesions ≤ 2 cm in diameter. The sensitivity/specificity for AP1 and AP2 for reader 1 was 89.9/97.6% and 95.5/90.6%, respectively, and those for reader 2 was 95.5/94.1% and 98.9/94.1%, respectively. The AUCs for AP1 and AP2 for reader 1 were 0.9629 and 0.9640 (p = 0.95), respectively, and those for reader 2 were 0.9755 and 0.9843 (p = 0.46), respectively. The detectability of the unenhanced abbreviated protocol based on DWI would be comparable to that of abbreviated postcontrast MRI for breast cancer.

Clinical use of cardiac PET/MRI: current state-of-the-art and potential future applications

Abstract: Combined PET/MRI is a novel imaging method integrating the advances of functional and morphological MR imaging with PET applications that include assessment of myocardial viability, perfusion, metabolism of inflammatory tissue and tumors, as well as amyloid deposition imaging. As such, PET/MRI is a promising tool to detect and characterize ischemic and non-ischemic cardiomyopathies. To date, the greatest benefit may be expected for diagnostic evaluation of systemic diseases and cardiac masses that remain unclear in cardiac MRI, as well as for clinical and scientific studies in the setting of ischemic cardiomyopathies. Diagnosis and therapeutic monitoring of cardiac sarcoidosis has the potential of a possible 'killer-application' for combined cardiac PET/MRI. In this article, we review the current evidence and discuss current and potential future applications of cardiac PET/MRI.

Artificial intelligence using neural network architecture for radiology (AINNAR): classification of MR imaging sequences

Abstract: The confusion of MRI sequence names could be solved if MR images were automatically identified after image data acquisition. We revealed the ability of deep learning to classify head MRI sequences. Seventy-eight patients with mild cognitive impairment (MCI) having apparently normal head MR images and 78 intracranial hemorrhage (ICH) patients with morphologically deformed head MR images were enrolled. Six imaging protocols were selected to be performed: T2-weighted imaging, fluid attenuated inversion recovery imaging, T2-star-weighted imaging, diffusion-weighted imaging, apparent diffusion coefficient mapping, and source images of time-of-flight magnetic resonance angiography. The proximal first image slices and middle image slices having ambiguous and distinctive contrast patterns, respectively, were classified by two deep learning imaging classifiers, AlexNet and GoogLeNet. AlexNet had accuracies of 73.3%, 73.6%, 73.1%, and 60.7% in the middle slices of MCI group, middle slices of ICH group, first slices of MCI group, and first slices of ICH group, while GoogLeNet had accuracies of 100%, 98.1%, 93.1%, and 94.8%, respectively. AlexNet significantly had lower classification ability than GoogLeNet for all datasets. GoogLeNet could judge the types of head MRI sequences with a small amount of training data, irrespective of morphological or contrast conditions.

Variations in the origins of the thyroid arteries on CT angiography.

Abstract: To investigate the anatomical variations in the origins of the thyroid arteries on CT angiography images. The presence and the origins of the superior thyroid artery, the inferior thyroid artery, and the thyroidea ima artery were retrospectively evaluated based on carotid CT angiography examinations. The bifurcation level of the common carotid artery with respect to the cervical vertebrae and disc spaces was also determined. A total of 640 patients were included in the study. The right and left superior thyroid arteries arose from the external carotid artery in 413 (64.5%) and 254 (39.7%) patients, from the bifurcation of the common carotid artery in 131 (20.5%) and 148 (23.1%) patients, and from the common carotid artery in 90 (14.1%) and 226 (35.3%) patients, respectively. We could not observe the right and the left superior thyroid arteries in 6 (0.9%) and 12 (1.9%) of the patients, respectively. However, the right and left inferior thyroid arteries were not identified in 14 (2.2%) and 45 (7%) of the patients, respectively. The thyroidea ima artery was detected in 2.3% of the patients. The visualization of thyroid arteries on CT angiography images enables the anatomy of the arterial supply system of the thyroid gland to be explored in a noninvasive manner prior to surgery.

Smoking-related lung abnormalities on computed tomography images: comparison with pathological findings

Abstract: Smoking-related lung abnormalities are now an increasing public health concern. According to the findings of large-cohort studies, approximately 8% of smokers have interstitial lung abnormalities, which are associated with a relatively high risk of all-cause mortality. We reviewed the radiological and pathological findings of smoking-related interstitial lung diseases, such as respiratory bronchiolitis-interstitial lung disease, desquamative interstitial pneumonia, and airspace enlargement with fibrosis. We have also discussed the histological basis of unclassifiable interstitial pneumonia in smokers, which exhibits airway-centered cystic lesions with fibrosis. A variety of radiological findings coexist in the lungs of a smoker. This overlapping of multiple pathological conditions might cause the radiological patterns of diseases to become unclassifiable. Therefore, diagnosis should be performed not on the basis of a single radiological finding, but in a comprehensive manner, by including clinical symptoms and disease behavior. Among interstitial abnormalities in smokers, the usual interstitial pneumonia (UIP) pattern is correlated with a worse prognosis than others. Basal-predominant subpleural reticulation is a clue for accurate diagnosis of UIP, which can be achieved by computer-aided quantitative analysis.

Grading system to categorize breast MRI using BI-RADS 5th edition: a statistical study of non-mass enhancement descriptors in terms of probability of malignancy

Abstract: To analyze the association of breast non-mass enhancement descriptors in the BI-RADS 5th edition with malignancy, and to establish a grading system and categorization of descriptors. This study was approved by our institutional review board. A total of 213 patients were enrolled. Breast MRI was performed with a 1.5-T MRI scanner using a 16-channel breast radiofrequency coil. Two radiologists determined internal enhancement and distribution of non-mass enhancement by consensus. Corresponding pathologic diagnoses were obtained by either biopsy or surgery. The probability of malignancy by descriptor was analyzed using Fisher’s exact test and multivariate logistic regression analysis. The probability of malignancy by category was analyzed using Fisher’s exact and multi-group comparison tests. One hundred seventy-eight lesions were malignant. Multivariate model analysis showed that internal enhancement (homogeneous vs others, p < 0.001, heterogeneous and clumped vs clustered ring, p = 0.003) and distribution (focal and linear vs segmental, p < 0.001) were the significant explanatory variables. The descriptors were classified into three grades of suspicion, and the categorization (3, 4A, 4B, 4C, and 5) by sum-up grades showed an incremental increase in the probability of malignancy (p < 0.0001). The three-grade criteria and categorization by sum-up grades of descriptors appear valid for non-mass enhancement.

Simultaneous whole-body and breast 18F-FDG PET/MRI examinations in patients with breast cancer: a comparison of apparent diffusion coefficients and maximum standardized uptake values

Abstract: To compare standardized uptake value (SUV) and apparent diffusion coefficient (ADC) values acquired using a PET/MRI scanner in breast cancer patients. Whole-body PET/MRI and breast PET/MRI were performed in 108 consecutive patients. Ninety-four patients who had a total of 100 breast cancers were analyzed. SUVmax and ADCmean acquired using breast PET/MRI were compared with pathologic prognostic factors. All the lesions were visually detectable using PET and diffusion-weighted imaging (DWI) on breast PET/MRI; however, lesions were visually undetectable on whole-body DWI in 13 patients (13%) or on whole-body PET in 7 patients (7%). An analysis of ADCmean and SUVmax demonstrated a statistically significant correlation between whole-body imaging and breast imaging (rho = 0.613, p < 0.001 and rho = 0.928, p < 0.001, respectively). In a univariate analysis, SUVmax was significantly correlated with HER2 status (p < 0.001), Ki-67 (p = 0.014), tumor size (p = 0.0177), and nuclear grade (p = 0.0448). In multiple regression analysis, only tumor size (p = 0.00701) was shown to independently influence SUVmax. Prone breast imaging was more sensitive than whole-body PET/MRI for detection of breast cancers. Both SUVmax and ADCmean showed limited correlation with pathologic prognostic factors.

Examining alterations in GABA concentrations in the basal ganglia of patients with Parkinson's disease using MEGA-PRESS MRS.

Abstract: The aim of this study was to compare the gamma-amino butyric acid (GABA) levels in the left basal ganglia (BG) of patients with Parkinson’s disease (PD) to those of healthy control (HC) volunteers using proton magnetic resonance spectroscopy (1H MRS). The GABA+ signal—the composite signal from GABA, macromolecules (MMs), and homocarnosine—was detected. GABA+ levels were examined in 21 PD patients and 15 age- and sex-matched HCs. 3T-1H-MRS using the Mescher–Garwood point-resolved spectroscopy (MEGA-PRESS) sequence was performed in order to detect GABA+ levels in the left BG, and the spectra were processed using the Gannet software. Differences in GABA+ levels between the two groups were analyzed using independent t-test analysis. The GABA+ levels were significantly lower (P < 0.001) in the left BG of the patients with PD (1.31 ± 0.21 i.u.) than in the left BG of the HCs (1.62 ± 0.26 i.u.). The lower GABA+ levels in the left BG of the PD patients suggest that GABA plays an important role in the pathogenesis of PD. The reduced GABA+ levels in the PD patients may be associated with GABAergic dysfunction.

Ultrasonography of traumatic injuries to limb peripheral nerves: technical aspects and spectrum of features

Abstract: Traumatic injury to limb peripheral nerves represents an important cause of morbidity and disability. Timely diagnosis and treatment are crucial to optimizing outcomes. The initial evaluation requires a careful history, a thorough physical examination, and electrodiagnostic tests, which lead in most cases to a diagnostic suspicion, but fail to provide an extensive qualitative and quantitative assessment of the nerve damage. Ultrasonography (US) is a low-cost, non-invasive technique which allows for direct visualization of nerve internal structure. It enables performing dynamic examinations and nerves can be followed over long distances in a limb in relatively short times, adding paramount information to extensively characterize the specific type of lesion, and to plan the appropriate treatment. Magnetic resonance imaging (MRI) is complementary to US, especially in examining deep-seated and proximal nerve segments, but is expensive, not available in all institutions and less accepted by patients. The purpose of this review is to describe the role of ultrasonography in the setting of traumatic injury to peripheral nerves, analyzing the main US features in specific types of trauma. Technical aspects with key considerations for optimization are discussed. A brief comparative evaluation between US and MRI is also provided.

18F-FDG PET/CT can predict chemosensitivity and proliferation of epithelial ovarian cancer via SUVmax value.

Abstract: This study aimed to explore the clinical and prognostic significance of 18F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) in epithelial ovarian cancer (EOC). We retrospectively investigated 48 EOC patients who underwent preoperative 18F-FDG PET/CT and primary cytoreductive surgery at our hospital between January 2010 and June 2015. None of these patients received neoadjuvant chemotherapy. PET/CT parameters including the maximum and average standardized uptake value (SUVmax, SUVavg), the metabolic tumor volume (MTV) were measured. Tumor proliferation marker Ki67 was evaluated using immunohistochemistry. The relationships between the PET/CT parameters and chemosensitivity, tumor proliferation, and overall survival (OS) were analyzed, respectively. The median (range) SUVmax, SUVavg, and MTV values were 11.42 (3.14–20.20), 4.8 (2.55–9.47), and 150.11 (0.19–792.46), respectively. Overall, 93.8% (45/48) of patients had high-grade serous ovarian cancer. The SUVmax value had a positive correlation with the Ki67 index (P = 0.030, r = 0.314), and a higher SUVmax level was associated with chemosensitivity (P = 0.026). However, neither SUVavg nor MTV had associations with the patients’ clinicopathological parameters. None of these three PET/CT parameters were found to be potential predictors of OS. Preoperative 18F-FDG PET/CT had a predictive value on chemosensitivity and proliferation after primary debulking surgery in EOC patients noninvasively.

Internal mammary lymph node metastases in breast cancer: what should radiologists know?

Abstract: The internal mammary lymph node (IMLN) chain is a pathway through which breast lymphatic drainage flows. The internal mammary lymphatic vessel runs around the internal mammary artery and veins with IMLN in the parasternal intercostal spaces. IMLN metastasis, which forms a part of clinical TNM staging, may negatively affect the prognosis of primary breast cancer patients. IMLN metastasis is clinically detected using ultrasound, computed tomography, magnetic resonance imaging, and 18F-deoxyglucose positron emission tomography computed tomography. The uptake of radioactive tracers in IMLN with clinically negative axillary lymph nodes is often identified using sentinel lymph node mapping (SLNM) in primary breast cancer patients. The indication for IMLN biopsy or resection that is clinically detected or visualized using SLNM is controversial. The clinically suspicious IMLN may be considered for ultrasound-guided fine-needle aspiration. First IMLN recurrence needs to be biopsied. Irradiation of the breast, chest wall, and/or regional nodal irradiation, including IMLN, following lumpectomy or postmastectomy is recommended. Although radiation therapy for IMLN recurrence may improve clinical outcomes, it is also associated with pulmonary and cardiac toxicities. This review covers the local anatomy of IMLN, lymph drainage and image findings of IMLN with a discussion.

Accuracy of early CT findings for predicting disease course in patients with acute pancreatitis.

Abstract: To investigate whether computed tomography (CT)-based scoring systems obtained within 72 h of symptoms onset can predict disease course in acute pancreatitis. Between October 2007 and December 2015, 189 patients (age range 21–93 years) who underwent abdominopelvic CT for the diagnosis of acute pancreatitis were included in the study. Balthazar grade and original and modified versions of CT severity index (CTSI) measurements were carried out for each patient. There were significant associations between each CT based scoring system and development of pancreatic and extrapancreatic complications (p 6 for CTSI and > 9 for the modified version of CTSI achieved a specificity of 98.7 and 99.2% for predicting pancreatic and extrapancreatic complications with areas under the curve (AUC) of 0.96 and 0.96, respectively. Balthazar grade of > C yielded a sensitivity of 98.4% for predicting pancreatic and extrapancreatic complications with an AUC of 0.95. The modified version of CTSI had the most significant association with pancreatic and extrapancreatic complications (HR: 3.22; p = 0.002, HR: 2.99, p = 0.003, respectively). Pancreatic necrosis was the only parameter significantly associated with mortality (HR: 5.83, p = 0.045). Early CT scan has an important role in prediction of complications and the management of acute pancreatitis.

Predictors of active arterial hemorrhage on angiography in pelvic fracture patients

Abstract: To determine predictors of active angiographic hemorrhage in pelvic fracture patients. This retrospective study included 66 trauma patients who had major hemorrhages due to pelvic fractures, and who underwent pelvic angiography between January 2012 and December 2014. The study population comprised 31 males and 35 females (mean age 44.2 ± 20.7 years). The main outcome was active hemorrhage on pelvic angiography. Clinical and imaging variables including demographics, hemodynamic parameters, injury severity, types of pelvic fracture, laboratory data, blood transfusions and CT findings were analyzed. Multivariate logistic regression was used to identify predictors of active angiographic hemorrhage. Of the 66 study patients included, 41 patients had active angiographic hemorrhage. These patients had more blood transfusions, higher activated partial thromboplastin times and higher rates of contrast extravasation on CT (p < 0.05). Three independent predictors of active angiographic hemorrhage were identified, including contrast extravasation on CT (OR: 74.6, p < 0.001), more than 8 units of RBC transfusions (OR: 12.5, p = 0.018) and ISS ≥ 16 (OR: 11.1, p = 0.029). Contrast extravasation on CT, high volume RBC transfusions and ISS ≥ 16 can help us to select pelvic fracture patients for angiography more precisely.

Definitive radiotherapy for hilar and/or mediastinal lymph node metastases after stereotactic body radiotherapy or surgery for stage I non-small cell lung cancer: 5-year results.

Abstract: The optimal treatment for hilar or mediastinal lymph node (LN) recurrence developing after stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer remains unclear. This study evaluated 5-year results of radiotherapy in such patients in comparison with those for postoperative LN metastases. Between 2004 and 2013, 27 patients with hilar and/or mediastinal LN metastases without local recurrence and distant metastasis after SBRT (n = 14) or surgery (n = 13) were treated with definitive conventional radiotherapy. The median total dose for treating metastatic LN was 60 Gy for the post-SBRT group and 66 Gy for the post-surgery group. The median follow-up for the 5 surviving patients was 62 months. The overall survival, cause-specific survival, progression-free survival, and local control rates at 5 years after mediastinal irradiation were 14%, 45%, 21%, and 58%, respectively, for the 14 patients in the post-SBRT group. These rates were 36%, 45%, 39%, and 92%, respectively for the post-surgery group (p = 0.066, 0.64, 0.38, and 0.41, respectively). Four patients in the post-SBRT group survived 3 or more years (range 36–92 months) after mediastinal irradiation. A proportion of patients in both groups achieved long-term survival by conventional radiotherapy.

Ultrasound imaging of the anorectal malformation during the neonatal period: a comprehensive review

Abstract: Anorectal malformation (ARM) is classified as low, intermediate, or high; accurate diagnosis of the type during the early neonatal period is important to determine the appropriate initial surgical approach. This review assesses the role of ultrasound examination in the classification of ARM during the neonatal period, with a focus on landmarks on the sonogram, the approach used for sonography, and the optimal examination timing. The following three factors on the sonogram are used for the classification: location of the fistula, the distance between the distal rectal pouch and the anal dimple (perineum) (P-P distance), and the relationship between the puborectalis muscle and the distal rectal pouch. Three approaches can be used to evaluate ARM by ultrasonography, namely, suprapubic, perineal, and infracoccygeal approaches. Each approach has its own advantages and disadvantages. Optimal timing of the ultrasound examination is also important with respect to each factor to classify ARM. We have described the pitfalls of ultrasound in diagnosis of cases, namely ARM with Down syndrome (which tends to be without fistula), ARM with low birth weight, ARM with unusual location of fistula, ARM with opened fistula (where the P-P distance is unreliable), and cloacal malformation (variation of the high-type ARM).

Changes in the ADC of diffusion-weighted MRI with the oscillating gradient spin-echo (OGSE) sequence due to differences in substrate viscosities

Abstract: Compared with the conventional pulsed gradient spin-echo (PGSE) sequence, diffusion-weighted imaging (DWI) with the oscillating gradient spin-echo (OGSE) sequence can shorten the diffusion time by changing the frequency. The purpose was to investigate whether n-alkanes are suitable as isotropic phantoms for estimating the diffusion coefficient with the OGSE sequence. We investigated changes in the apparent diffusion coefficient (ADC) due to differences in the viscosities of nine n-alkane phantoms with different numbers of carbon atoms from C8H18 to C16H34 using OGSE and PGSE sequences at 21 °C. Effective diffusion times of 4.3, 5.1, 6.5, 9.3, 20, 40, and 60 ms were used. The T2 relaxation times of each n-alkane phantom were measured using quantitative synthetic magnetic resonance imaging (MRI). Circular regions of interest were placed manually within the alkane phantoms on ADC and T2 maps. In each alkane phantom, changes in mean ADC values were almost constant with changes in diffusion times. Viscosities and ADC values showed inverse proportionality, as expected theoretically. The ADC values of alkanes do not depend on diffusion times. The n-alkanes can be useful phantoms for assessing the accuracy of clinical protocols of DWI with the OGSE sequence.

DCE-MRI time–intensity curve visual inspection to assess pathological response after neoadjuvant therapy in locally advanced rectal cancer

Abstract: To investigate the potential of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to discriminate responder from non-responder patients after preoperative chemoradiotherapy (pCRT) in locally advanced rectal cancer (LARC). One hundred and fifty-eight consecutive patients were enrolled in this prospective study. We compared morphological MRI (mMRI) using T2-weighted images about tumor presence and invasiveness, and functional DCE-MRI using time–intensity curve (TIC) visual inspection (qMRI), classifying TIC shape into three types: type 1, persistent enhancement; type 2, high enhancement with plateau; type 3, high enhancement with wash-out. Clinical TNM was obtained before and after CRT by radiological consensus of two expert radiologists. Pathological tumor–nodes–metastasis classification and tumor regression grade (TRG) were confirmed as the golden standard. Non-parametric test, sensitivity, specificity, and positive and negative predictive values were calculated. Ninety-eight patients (62%) were classified as responders (TRG ≤ 2), while 60 (38%) were classified as non-responders. Sensitivity, specificity, and accuracy were 52, 78, and 62% for mMRI, and 81, 85, and 82% for qMRI, respectively. TIC visual inspection may be one of the potential biomarkers over morphological analysis using DCE-MRI data to assess pathological response after pCRT in LARC.

Three-dimensional computed tomographic angiography with computed tomographic colonography for laparoscopic colorectal surgery

Abstract: To prospectively correlate the preoperative vessel anatomy in three-dimensional computed tomographic angiography with computed tomographic colonography (3D-CTA with CTC) with that in laparoscopic surgery for colorectal cancer. The study protocol was approved by our institutional review board. The study population consisted of 101 patients with colon cancer who underwent 3D-CTA with CTC between June 2016 and January 2018. Two radiologists assessed the branching patterns of sigmoid arteries (SAs) and right colonic artery (RCA), the position between the ileocolic artery (ICA) and superior mesenteric vein (SMV), and the existence of an accessory middle colonic artery (aMCA). The vessel anatomy on 3D-CTA with CTC was correlated with that of intraoperative findings. Ninety-eight examinations (97.0%) were technically successful. Between preoperative and intraoperative vessel anatomy, the branching patterns of SAs were concordant in all 29 cases with rectosigmoid and descending colon cancer. The branching patterns of RCA and the position between the ICA and SMV were completely concordant in 32 cases of cecal and ascending colon cancer. No aMCA was identified either intraoperatively or by imaging analysis. 3D-CTA with CTC guided the surgeons to determine the resection margin of the relevant vessels for laparoscopic colorectal surgery.