Development and multicenter validation of deep convolutional neural network-based detection of colorectal cancer on abdominal CT.

OBJECTIVES: This study aims to develop computer-aided detection (CAD) for colorectal cancer (CRC) using abdominal CT based on a deep convolutional neural network. METHODS: This retrospective study included consecutive patients with colorectal adenocarcinoma who underwent abdominal CT before CRC resection surgery (training set = 379, test set = 103). We customized the 3D U-Net of nnU-Net (CUNET) for CRC detection, which was trained with fivefold cross-validation using annotated CT images. CUNET was validated using datasets covering various clinical situations and institutions: an internal test set (n = 103), internal patients with CRC first determined by CT (n = 54) and asymptomatic CRC (n = 51), and an external validation set from two institutions (n = 60). During each validation, data from the healthy population were added (internal = 60; external = 130). CUNET was compared with other deep CNNs: residual U-Net and EfficientDet. The CAD performances were evaluated using per-CRC sensitivity (true positive/all CRCs), free-response receiver operating characteristic (FROC), and jackknife alternative FROC (JAFROC) curves. RESULTS: CUNET showed a higher maximum per-CRC sensitivity than residual U-Net and EfficientDet (internal test set 91.3% vs. 61.2%, and 64.1%). The per-CRC sensitivity of CUNET at false-positive rates of 3.0 was as follows: internal CRC determined by CT, 89.3%; internal asymptomatic CRC, 87.3%; and external validation, 89.6%. CUNET detected 69.2% (9/13) of CRCs missed by radiologists and 89.7% (252/281) of CRCs from all validation sets. CONCLUSIONS: CUNET can detect CRC on abdominal CT in patients with various clinical situations and from external institutions. KEY POINTS: • Customized 3D U-Net of nnU-Net (CUNET) can be applied to the opportunistic detection of colorectal cancer (CRC) in abdominal CT, helping radiologists detect unexpected CRC. • CUNET showed the best performance at false-positive rates ≥ 3.0, and 30.1% of false-positives were in the colorectum. CUNET detected 69.2% (9/13) of CRCs missed by radiologists and 87.3% (48/55) of asymptomatic CRCs. • CUNET detected CRCs in multiple validation sets composed of varying clinical situations and from different institutions, and CUNET detected 89.7% (252/281) of CRCs from all validation sets.

Abbreviated MRI with second shot arterial phase for HCC evaluation: modified version of LI-RADS and recall reduction strategy.

OBJECTIVES: To evaluate the feasibility of simulated abbreviated MRI (AMRI) with second shot arterial phase (SSAP) for HCC surveillance and diagnosis. METHODS: A total of 129 consecutive patients (age, 58.8 ± 11.4 years; male, 71.3%) underwent gadoxetic acid-enhanced MRI using a modified injection protocol for HCC evaluation from July 2017 to February 2018. The modified injection protocol consisted of routine dynamic imaging (6 mL) and SSAP imaging (4 mL). Two radiologists independently reviewed two AMRI sets: AMRI without SSAP (surveillance set) and AMRI with SSAP (diagnosis set). A modified version of the Liver Imaging Reporting and Data System (LI-RADS) for the diagnosis set was devised by referring to contrast-enhanced ultrasound LI-RADS. RESULTS: Sixty-seven patients with HCC and 62 patients without HCC were included. In the surveillance set, sensitivity and specificity for the detection of patients with HCC were 95.5% and 96.8%, and 94.0% and 96.8% in reviewers 1 and 2, respectively. In the diagnosis set, the scores of most HCCs (76/78, 97.4%) were consistent between LI-RADS of full-protocol and modified LI-RADS of AMRI with SSAP protocol. When the HCC surveillance and diagnosis strategy was changed from strategy 1 (AMRI without SSAP) to strategy 2 (AMRI with SSAP), the recall rate significantly decreased from 52.7 to 3.9% (p < 0.001). CONCLUSIONS: The modified LI-RADS score of the AMRI with SSAP protocol showed high agreement with the LI-RADS score of the full protocol. The HCC surveillance and diagnosis strategy using the AMRI with SSAP protocol reduced the recall rate. These results may enable to diagnose HCC simultaneously with surveillance. KEY POINTS: • A modified version of LI-RADS was devised for the diagnostic algorithm using AMRI with the second shot arterial phase (SSAP) by referring to CEUS LI-RADS. • The modified LI-RADS scores using AMRI with SSAP showed a high concordance rate with the conventional LI-RADS score using full-protocol MRI. • The recall rate significantly decreased when the HCC surveillance and diagnosis strategy was changed from strategy 1 (AMRI without SSAP; surveillance then recall test) to strategy 2 (AMRI with SSAP; simultaneous surveillance and diagnosis).

Transabdominal Ultrasound for Follow-Up of Incidentally Detected Low-Risk Pancreatic Cysts: A Prospective Multicenter Study.

OBJECTIVE. The purpose of this study is to investigate the detection rate of transabdominal ultrasound (TAUS) for pancreatic cysts incidentally detected on CT or MRI as well as the factors that influence detection rates. SUBJECTS AND METHODS. Fifty-seven patients with low-risk pancreatic cysts (n = 77; cyst size, 5 mm to 3 cm) that were incidentally detected on CT or MRI were prospectively enrolled at five institutions. At each institution, TAUS was independently performed by two radiologists who assessed detection of cysts, cyst location and size, and the diameter of the main pancreatic duct (MPD). Cyst detection rates based on cyst size, location, and multiplicity and the body mass index of the patient were compared using the Mann-Whitney test. Kappa statistics and the interclass correlation coefficient were used to evaluate interobserver agreement regarding cyst detection and consistency of cyst size and the diameter of the MPD on TAUS versus prior CT or MRI. RESULTS. The detection rate for known low-risk pancreatic cysts was 81.8% (63/77) and 83.1% (64/77) for TAUS conducted by each of the two radiologists. The detection rate for larger (≥ 10 mm) cysts was significantly higher than that for smaller cysts (89.0% vs 63.6% for TAUS performed and interpreted by radiologist 1 [TAUS 1] and 89.0% vs 68.2% for TAUS conducted and interpreted by radiologist 2 [TAUS 2]; p < .05). A higher detection rate was noted for cysts located outside the tail of the pancreas compared with those located in the tail (89.5% vs 65.0% for TAUS 2; p = .01), and the detection rate was also significantly higher for single cysts than for multiple cysts (90.9% vs 69.7% for TAUS 1; p = .02). However, no significant difference was observed for body mass index. Interobserver agreement was excellent regarding the size of the detected cysts (inter-class correlation coefficient: 0.964 [95% CI, 0.940-0.979] for CT, TAUS 1, and TAUS 2 and 0.965 [95% CI. 0.924-986] for MRI, TAUS 1, and TAUS 2) and the diameter of the MPD (interclass correlation coefficient, 0.934; 95% CI, 0.898-0.959). CONCLUSION. TAUS could be a useful alternative imaging tool for surveillance of known low-risk pancreatic cysts, especially single pancreatic cysts and those that are of larger size (≥ 1 cm) or are located outside the tail.

Second shot arterial phase to overcome degraded hepatic arterial phase in liver MR imaging.

OBJECTIVES: Second shot arterial phase (SSAP) imaging is an additional arterial phase image obtained by re-injecting a small amount of contrast medium after routine dynamic imaging in gadoxetic acid-enhanced liver MRI. We aimed to evaluate the feasibility and additional value of a SSAP image in gadoxetic acid-enhanced liver MRI. METHODS: One hundred seventy-two patients who underwent SSAP imaging after re-injection of 4 mL of contrast material after routine dynamic imaging (original) in gadoxetic acid-enhanced liver MRIs were included. Motion artifacts on arterial phase (AP) images were rated using a 5-point scale and were compared between the original AP images and SSAP images. We evaluated visual detection rates of arterial hypervascularity on the original AP and SSAP images and their subtraction images in patients with hypervascular hepatocellular carcinoma (HCC). RESULTS: The motion artifact of the SSAP images was significantly lower than that of the original AP images (mean score, 1.76 vs 2.06; p < 0.001). In particular, motion artifacts reduced significantly in the SSAP images of patients with substantial motion artifacts in their original AP images (2.28 vs 3.28; p < 0.001). Among the 30 HCC lesions showing hypervascularity on original AP images, only four (4/30, 13.3%) appeared hyperintense on SSAP images. However, subtraction images of SSAP clearly demonstrated arterial hypervascularity in all HCCs. CONCLUSION: SSAP images showed significantly fewer motion artifacts than the original AP images. Subtraction images of SSAP maintained the detectability of arterial hypervascularity, although SSAP images showed poor visual detection of arterial hypervascularity of HCC. KEY POINTS: • Arterial phase images obtained after a second injection of a small amount of contrast medium (second shot arterial phase [SSAP]) improved motion artifacts compared to the original AP images. • The motion artifacts improved significantly in the SSAP images of patients with substantial motion artifacts in their original AP images. • Subtraction images of SSAP demonstrated the arterial hypervascularity characteristic of HCC at a level comparable to that of the original AP image.

Newly Categorized Seromucinous Tumor of the Ovary: Magnetic Resonance Imaging Findings.

OBJECTIVE: The aim of this study was to describe magnetic resonance imaging findings of newly categorized ovarian seromucinous tumors. METHODS: We retrospectively reviewed the images of 29 patients with seromucinous tumor for the following factors: size, configuration, signal intensity (SI), and accompanying ovarian endometriosis. RESULTS: Thirty-two tumors (17 benign, 7 borderline, 8 carcinoma) were found on computed tomography or magnetic resonance imaging. Their mean size was 11.4 cm. Benign tumors appeared as unilocular or multilocular cystic masses. Borderline tumors and carcinomas appeared as complex cystic-solid masses. T2-weighted SI of the solid portion was hyperintense in borderline tumors and intermediate in carcinomas. Endometriosis was present in 18 tumors, and hemorrhage (on images) in 20. CONCLUSIONS: The imaging features of seromucinous tumors varied by tumor type. More than half of tumors were accompanied by endometriosis. High T2-weighted SI of the solid portion could be a specific feature of borderline tumors. It is hard to differentiate seromucinous carcinomas from other endometriosis-related carcinomas.

Use of Imaging to Predict Complete Response of Colorectal Liver Metastases after Chemotherapy: MR Imaging versus CT Imaging.

Purpose To compare the diagnostic performances of contrast agent-enhanced computed tomography (CT) and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced liver magnetic resonance (MR) imaging (referred to as EOB MR imaging) in the evaluation of disappearing colorectal liver metastases (CRLMs) after chemotherapy. Materials and Methods The eight institutional review boards approved this retrospective study and waived the requirement for informed consent. On the basis of retrospective searches in eight hospitals, 87 patients with 393 CRLMs, each patient with one or more CRLM that later disappeared on contrast-enhanced CT scans after chemotherapy, and subsequently underwent surgery for the CRLMs, were enrolled. The anonymized imaging data and case report forms were sent to the central review system and independently reviewed by four radiologists. All anonymized data were randomly allocated into two groups (groups A and B), which were read by two independent readers. True absence of tumor was defined as pathologic absence of tumor for resected lesions and no in situ recurrence within 1 year after surgery for lesions left unresected at each 3-month follow-up contrast-enhanced CT. Positive predictive values for absence of tumor and for residual tumor on contrast-enhanced CT and EOB MR images were compared by using a generalized estimating equation. Results Among 393 CRLMs, the positive predictive value for absence of tumor on EOB MR images (78.0%; 95% confidence interval [CI]: 63.68%, 87.74%) was significantly higher than that on contrast-enhanced CT scans (35.2%; 95% CI: 25.11%, 46.79%; P < .001). The positive predictive value for residual tumor on CT scans (86.0%; 95% CI: 78.61%, 91.16%) was higher than that on EOB MR images (83.8%; 95% CI: 77.50%, 88.67%) without statistical significance (P = .330). Conclusion EOB MR imaging was superior to contrast-enhanced CT imaging for assessment of disappearing CRLMs after chemotherapy. © RSNA, 2017 Online supplemental material is available for this article.

Comparison of biannual ultrasonography and annual non-contrast liver magnetic resonance imaging as surveillance tools for hepatocellular carcinoma in patients with liver cirrhosis (MAGNUS-HCC): a study protocol.

BACKGROUND: Ultrasonography (US) is recommended as a standard surveillance tool for patients with a high risk of developing hepatocellular carcinoma (HCC). However, the low sensitivity of US for small HCC can lead to surveillance failure, resulting in advanced stage tumor presentations. For the early detection of HCC in high-risk patients and to improve survival and prognosis, a new efficient imaging tool with a high sensitivity for HCC detection is needed. The purpose of this study is to evaluate and compare the feasibility and efficacy of non-contrast magnetic resonance imaging (MRI) with US as a surveillance tool for HCC in patients with liver cirrhosis. METHODS: MAGNUS-HCC is a prospective, multicenter clinical trial with a crossover design for a single arm of patients. This study was approved by six Institutional Review Boards, and informed consent was obtained from all participants. All patients will undergo liver US every 6 months and non-contrast liver MRI every 12 months during a follow-up period of 3 years. If a focal liver lesion suspected of harboring HCC is detected, dynamic liver computed tomography (CT) will be performed to confirm the diagnosis. After the last surveillance round, patients without suspicion of HCC or who are not diagnosed with HCC will be evaluated with a dynamic liver CT to exclude false-negative findings. The primary endpoint is to compare the rate of detection of HCC by US examinations performed at 6-month intervals with that of yearly non-contrast liver MRI studies during a 3-year follow-up. The secondary endpoint is the survival of the patients who developed HCC within the 3-year follow-up period. DISCUSSION: MAGNUS-HCC is the first study to compare the feasibility of non-contrast MRI with US as a surveillance tool for the detection of HCC in high-risk patients. We anticipate that the evidence presented in this study will establish the efficacy of non-contrast MRI as a surveillance tool for HCC in high-risk patients. TRIAL REGISTRATION: The date of trial registration ( NCT02551250 ) in this study was September 15, 2015, and follow-up is still ongoing.

Washout appearance in Gd-EOB-DTPA-enhanced MR imaging: A differentiating feature between hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase and focal nodular hyperplasia-like nodules.

PURPOSE: To identify the most reliable imaging features for differentiating hepatocellular carcinoma with paradoxical uptake on the hepatobiliary phase (HCCpara ) from focal nodular hyperplasia (FNH)-like nodules using Gd-EOB-DTPA-enhanced MRI. MATERIALS AND METHODS: This was a retrospective study. Twenty patients with HCCpara and 21 patients with FNH-like nodules were included. The following MRI features were evaluated using 3.0 Tesla unit by two radiologists: signal intensity (SI) on T1-, T2-, and diffusion-weighted imaging (DWI), arterial enhancement pattern, washout appearance on the portal venous phase (PVP) and/or transitional phase (TP), uptake pattern on the hepatobiliary phase (HBP), "T2 scar," "EOB scar," and chemical shift on in- and out-of-phase images. Multivariate logistic regression analysis was performed to assess MRI features for prediction of HCCpara . RESULTS: Compared with FNH-like nodules, HCCpara had significantly more frequent heterogeneous T1 SI (P < 0.0001), T2 hyperintensity (P = 0.032), heterogeneous arterial enhancement (P < 0.0001), washout appearance on the PVP and/or TP (P < 0.0001), heterogeneous uptake on the HBP (P < 0.0001), absence of "EOB scar" (P < 0.0001), and hyperintensity on DWI (P = 0.004). Multivariate logistic regression analysis revealed washout appearance as the only independent imaging feature associated with HCCpara (odds ratio, 7.019; P = 0.042). Washout appearance also showed the best diagnostic performance with a sensitivity of 90% and a specificity of 100%. CONCLUSION: Washout appearance on the PVP and/or TP is the most reliable imaging feature for differentiating HCCpara from FNH-like nodules. LEVEL OF EVIDENCE: 3 J. MAGN. RESON. IMAGING 2017;45:1599-1608.

Low-Tube Voltage Computed Tomography During Hepatic Arterial Phase: The Effect of Body Habitus on Image Quality.

PURPOSE: This study aimed to evaluate the impact of body habitus factors on image quality of low-tube voltage computed tomography (CT) during the hepatic arterial phase. MATERIALS AND METHODS: Ninety-seven patients (66 men, 31 women; age range, 26-78 years) who underwent clinically indicated liver dynamic CT examination were enrolled in the study. Analysis with 80-kVp CT and intermediate tube current (277-337 mA) was performed in the late hepatic arterial phase using a 320-detector row scanner with adaptive iterative dose reduction 3-dimensional reconstruction. Patient body habitus was measured using body weight (BW), body mass index (BMI), lateral width (LW) of the abdomen, and muscle volume (MV) of the abdominal wall. On hepatic arterial phase, the mean image noise and contrast-to-noise ratio (CNR) for the aorta and liver were assessed. The correlations between body habitus factors and image quality parameters were evaluated. RESULTS: In all patients, MV showed the strongest correlation with image noise, followed by BW and LW (r = 0.684, 0.570, and 0.555, respectively). The BMI showed the fourth strongest correlation with image noise among all body habitus factors (r = 0.377). With respect to CNR of the aorta, MV and BW showed the strongest inverse correlation (r = -0.590 and -0.600, respectively), followed by LW and BMI (r = -0.557 and -0.423, respectively). Regarding the CNR of the liver, MV showed the strongest inverse correlation (r = -0.279), although the correlation efficiency was weak compared with other correlations. CONCLUSIONS: Among various body habitus factors, MV showed the strongest association with image noise and CNR in the hepatic arterial phase using 80-kVp CT.

Intravoxel incoherent motion magnetic resonance imaging to predict vesicoureteral reflux in children with urinary tract infection.

OBJECTIVES: To compare the diffusion parameters of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) between the "reflux" and the "non-reflux" kidneys, and to evaluate the feasibility of using IVIM DWI to predict vesicoureteral reflux (VUR) in children with a urinary tract infection (UTI). METHODS: Eighty-three kidneys from 57 pediatric patients with a UTI were classified into "reflux" and "non-reflux" groups according to voiding cystourethrography (VCUG) results. The apparent diffusion coefficient (ADC), true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (PF) were measured and compared in the renal pelvis of both groups. Four indices (D*/ADC, PF/ADC, D*/D, and PF/D) were calculated and receiver operating characteristic (ROC) curve analyses were performed. RESULTS: VURs were detected on VCUG in 21 kidneys. PF and D* were significantly higher in the "reflux" group than in the "non-reflux" group. The indices were all significantly higher. The PF/D index showed the best diagnostic performance in predicting VUR in children with UTI (Az = 0.864). CONCLUSION: PF and D* were significantly higher in the "reflux" kidney than in the "non-reflux" kidney. Our new index (PF/D) could prove useful for predicting VUR. KEY POINTS: • IVIM DWI is both radiation-free and contrast media-free. • IVIM DWI index is easily calculated by combining diffusion parameters. • IVIM DWI may help predict VUR in children with UTI. • PF is significantly higher in the "reflux" than the "non-reflux" kidneys. • A new VUR index, PF/D could prove useful for predicting VUR.

Using intravoxel incoherent motion MR imaging to evaluate cortical defects in the first episode of upper urinary tract infections: preliminary results.

PURPOSE: To compare intravoxel incoherent motion diffusion weight imaging IVIM-DWI MRI with DMSA for the evaluation of cortical defect in pediatric upper urinary tract infection (UTI) patients. MATERIALS AND METHODS: Forty-three kidneys of 22 pediatric patients with the first episode of febrile upper UTI were evaluated. DWI using IVIM model was performed with eight b factors. The presence of cortical defect was evaluated on apparent diffusion coefficient (ADC) map. DMSA was used as the standard of reference. ADC, true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (F) in both defect and nondefect area were calculated and compared. RESULTS: Cortical defects were detected in 14 kidneys by IVIM-DWI. The sensitivity, specificity, positive predictive value, and negative predictive value of IVIM-DWI MRI for the detection of defects was 93.3%, 100%, 100%, and 96.5%, respectively. Mean values of ADC, D, D*, and F were 1.12 ± 0.15, 1.05 ± 0.10, 33 ± 17 (× 10(-3) mm(2) /s), and 0.14 ± 0.09 in the defect foci. In normal foci, ADC, D, D*, and F were 1.37 ± 0.09, 1.31 ± 0.10, 43 ± 19 (× 10(-3) mm(2) /s), and 0.12 ± 0.04, respectively. ADC and D were significantly lower in defect group than nondefect group (P < 0.01). CONCLUSION: IVIM-DWI can allow both direct visualization and quantitative measurement of cortical defects.

Intraoperative contrast-enhanced sonographic portography combined with indigo carmine dye injection for anatomic liver resection in hepatocellular carcinoma: a new technique.

We present a method of intraoperative contrast-enhanced sonographic portography combined with indigo carmine dye injection for anatomic liver resection in hepatocellular carcinoma. During surgery, before dye infusion into the feeding portal vein, the targeted portal vein branch was directly punctured, and a microbubble contrast agent was administered under sonographic guidance. Simultaneous enhancement of the resected hepatic parenchyma with a microbubble contrast agent and blue dye improved estimation of the segmental border in the cutting plane and the tumor resection margin during liver surgery.

"Nondefect" of arterial enhancing rim on hepatobiliary phase in 3.0-T gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced liver magnetic resonance imaging: distinguishing hepatic abscess from metastasis.

OBJECTIVE: The objective of this study was to retrospectively determine the findings of Gd-EOB-DTPA (gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid)-enhanced magnetic resonance imaging (MRI) to distinguish abscess from metastasis of the liver. METHODS: Among patients who underwent Gd-EOB-DTPA MRI from March 2008 to December 2011, 32 patients with abscess or metastasis were included, and all lesions showed arterial rim enhancement. Twenty-one abscesses and 19 metastases were included. Two radiologists assessed how the arterial enhancing rim showed in hepatobiliary phase (HBP) and classified the signal intensity of the rim into defect zone, gray zone, and uptake zone. The frequency of showing nondefect, which means gray or uptake zone between both lesions, was compared using Pearson χ test. RESULTS: The rim of arterial enhancement in 3 abscesses (14.3%) and 15 metastases (78.9%) showed defect zone in HBP. Six abscesses (28.6%)and no metastases showed gray zone, and 12 abscesses (57.1%) and 4 metastases (21.1%) showed uptake zone. The frequency of nondefect in the rim of arterial enhancement on HBP was significantly higher in abscesses (85.7% of abscesses, 21.1% of metastases, P < 0.001). CONCLUSIONS: A reliable finding that distinguished abscess from metastasis was nondefect of arterial enhancing rim on HBP in Gd-EOB-DTPA MRI. This is a meaningful feature for differentiating abscess from metastasis, especially when evaluating patients with primary malignancy.

Contrast-enhanced sonography for screening of vascular complication in recipients following living donor liver transplantation.

The purpose of this article is to discuss the role of CEUS for screening of vascular complication in recipients admitted to ICU following LDLT, effect of microbubble contrast agent on Doppler phenomenon, CEUS technique, and illustrate CEUS findings in recipients with complication following LDLT. CEUS can enhance the role of US in the diagnosis of postoperative vascular complication in recipients following living donor liver transplantation at the bedside.

Usefulness of Corticomedullary-Phase CT Urography in Patients with Suspected Acute Renal Colic Visiting the Emergency Department.

Purpose: To evaluate the sensitivity of corticomedullary-phase imaging for detecting urinary stones in patients with renal colic who visited the emergency department. Materials and Methods: This retrospective study included 253 patients with suspected renal colic from two tertiary hospitals in South Korea, who visited the emergency department and underwent CT urography. Two radiologists blinded to the clinical history independently reviewed the corticomedullary-phase images. The sensitivity for identifying urinary stones were evaluated for each reviewer. After the initial evaluation, the images were re-evaluated based on patient history. The sensitivity of re-evaluation were recorded. Results: Of 253 patients, 150 (59%) had urinary stones. Among them, significant stones were observed in 138 patients (92%), and obstructive changes on CT in 124 patients (82.7%). For identifying significant urinary stones, the sensitivity was 98.6% (136/138) for both the reviewers. For identifying significant urinary stones with urinary obstruction, the sensitivity was 99.2% (123/124) for reviewer 1, and 100% (124/124) for reviewer 2. The sensitivity for identifying significant stones increased from 98.6% to 100% for reviewer 1, and from 98.6% to 99.3% for reviewer 2 in the re-evaluation session. Conclusion: The corticomedullary-phase CT urography was sensitive for diagnosing urolithiasis in patients with acute renal colic who visited the emergency department.

Clear Cell Borderline Tumor of the Ovary: A Case Report.

Clear cell borderline ovarian tumor (CCBOT) is quite rare, and only a few cases of CCBOT have been reported. Unlike most borderline ovarian tumors, CCBOTs appear solid because they are almost always pathologically adenofibromatous. Herein, we report the MRI findings of a CCBOT discovered in a 22-year-old female.

Hepatocellular carcinoma pathologic grade prediction using radiomics and machine learning models of gadoxetic acid-enhanced MRI: a two-center study.

PURPOSE: To develop a radiomics-based hepatocellular carcinoma (HCC) grade classifier model based on data from gadoxetic acid-enhanced MRI. METHODS: This retrospective study included 137 patients who underwent hepatectomy for a single HCC and gadoxetic acid-enhanced MRI within 60 days before surgery. HCC grade was categorized as low or high (modified Edmondson-Steiner grade I-II vs. III-IV). We used the hepatobiliary phase (HBP), portal venous phase, T2-weighted image(T2WI), and T1-weighted image(T1WI). From the volume of interest in HCC, 833 radiomic features were extracted. Radiomic and clinical features were selected using a random forest regressor, and the classification model was trained and validated using a random forest classifier and tenfold stratified cross-validation. Eight models were developed using the radiomic features alone or by combining the radiomic and clinical features. Models were validated with internal enrolled data (internal validation) and a dataset (28 patients) at a separate institution (external validation). The area under the curve (AUC) of the validation results was compared using the DeLong test. RESULTS: In internal and external validation, the HBP radiomics-only model showed the highest AUC (internal 0.80 ± 0.09, external 0.70 ± 0.09). In external validation, all models showed lower AUC than those for internal validation, while the T2WI and T1WI models failed to predict the HCC grade (AUC 0.30-0.58) in contrast to the internal validation results (AUC 0.67-0.78). CONCLUSION: The radiomics-based machine learning model from gadoxetic acid-enhanced liver MRI could distinguish between low- and high-grade HCCs. The radiomics-only HBP model showed the best AUC among the eight models, good performance in internal validation, and fair performance in external validation.

Obstruction at middle hepatic venous tributaries in modified right lobe grafts after living-donor liver Transplantation: diagnosis with contrast-enhanced US.

PURPOSE: To investigate the ability of contrast material-enhanced ultrasonography (US) to help diagnose obstruction of middle hepatic venous (MHV) tributaries soon after living-donor liver transplantation with modified right lobe grafts. MATERIALS AND METHODS: The institutional review board approved the study and waived requirement for informed consent. Sixty-five consecutive patients (48 men, 17 women; mean age, 52.8 years; range, 33-69 years) who underwent living-donor liver transplantation with modified right lobe grafts between February and May 2009 were included. All patients underwent contrast-enhanced US and Doppler US on postoperative day 1 and underwent computed tomography (CT) within 7 days after US. At contrast-enhanced US, parenchymal enhancement patterns in the territory of each MHV tributary during arterial and portal venous phases were evaluated. With use of most frequent enhancement patterns in patients with obstruction at MHV tributaries as a criterion, diagnostic performance of contrast-enhanced US was compared with that of Doppler US for diagnosis of obstruction at MHV tributaries; CT was the reference standard. Generalized estimating equations were used to adjust for data clustering. RESULTS: Of 148 MHV tributaries in 65 patients, 36 (24.3%) in 31 patients were diagnosed as obstructed at CT. With arterial high echogenicity or portal low echogenicity used as a criterion for hepatic venous obstruction, contrast-enhanced US had sensitivity, specificity, and accuracy of 91% (33 of 36), 97% (109 of 112), and 95% (142 of 148), respectively, whereas Doppler US had values of 83% (30 of 36), 86% (97 of 112), and 85% (127 of 148), respectively. Contrast-enhanced US was significantly more specific and accurate than Doppler US for diagnosis of obstruction at MHV tributaries (P=.024 and .01, respectively). Arterial high echogenicity was noted only in the hepatic venous obstruction group. CONCLUSION: Contrast-enhanced US can help accurately assess hepatic venous obstruction at MHV tributaries after living-donor liver transplantation with a modified right lobe graft. Contrast-enhanced US was significantly more specific than Doppler US, with arterial hyperenhancement in the affected area being specific to hepatic venous obstruction.

The effectiveness of erythromycin in reducing stent-related tissue hyperplasia: an experimental study with a rat esophageal model.

BACKGROUND: Erythromycin is not only a potent antibiotic; it also has effects of reduction of inflammation and suppression of protein synthesis. PURPOSE: To evaluate the impact of erythromycin on tissue hyperplasia after stent placement in a rat esophageal model. MATERIAL AND METHODS: A total of 21 rats were included. After placement of self-expanding stents in the mid esophagus, the rats were divided into two experimental groups and one control group. The rats in the experimental groups received daily intraperitoneal injections of erythromycin for 5 weeks; 4 mg/kg (group A, n = 7) and 8 mg/kg (group B, n = 7). Those in the control group (n = 7) received 1 mL of saline intraperitoneally. After sacrifice, histologic analysis was done for thickness of the papillary projection, granulation tissue area, percentage of granulation tissue area, and degree of inflammatory cell infiltration. The statistical significance of differences between groups was assessed by Mann-Whitney U test. RESULTS: Tissue hyperplasia as reflected in thickness of papillary projection, granulation tissue area, and percentage of granulation tissue area, was higher in the control group than in the experimental groups, although there was no statistical significance (P = 1.00, 0.332, and 0.263, respectively). However, degree of inflammatory cell infiltration was significantly lower in the experimental groups than the control group (P = 0.025), and the higher dosage of erythromycin reduced inflammatory cell infiltration significantly (P = 0.037). CONCLUSION: Intraperitoneal administration of erythromycin is very effective in reducing inflammation after stent placement in a rat esophageal model but has no significant effect on granulation tissue formation.

Ultrasonographic atlas of splenic lesions.

Ultrasonography (US) is widely used for abdominal imaging. Its noninvasiveness, extensive range of application, and low cost make US a useful and valuable tool for the detection, diagnosis, and follow-up of splenic abnormalities. Concomitantly with the increasing frequency of imaging, more splenic lesions are being discovered and the requirements for the differential diagnosis are rising. In this pictorial essay, we introduce the representative US findings of many different splenic lesions, including normal sonographic findings, normal variants and congenital anomalies, infectious conditions, benign and malignant neoplasms, and non-neoplastic lesions. Knowledge of the US features of various splenic lesions will help narrow the differential diagnosis and guide clinical decision-making.