Utility of abbreviated MRI in the post-treatment evaluation of rectal cancer.

BACKGROUND: Post-treatment evaluation of patients with rectal cancer (RC) using magnetic resonance imaging (MRI) burdens medical resources, necessitating an exploration of abbreviated protocols. PURPOSE: To evaluate the diagnostic performance of abbreviated MRI (A-MRI) for the post-treatment evaluation of RC patients. MATERIAL AND METHODS: This retrospective study included RC patients who underwent non-contrast rectal MRI and standard liver MRI, as well as abdominal contrast-enhanced computed tomography (CECT) for post-treatment evaluation. A-MRI comprised diffusion-weighted imaging (DWI) and T2-weighted imaging of the upper abdomen and the pelvic cavity. Three radiologists independently reviewed A-MRI, CECT, and standard liver MRI in the detection of viable disease. The diagnostic performances were compared using a reference standard considering all available information, including pathology, FDG-PET, endoscopic results, and clinical follow-up. RESULTS: We included 78 patients (50 men, 28 women; mean age=60.9 ± 10.2 years) and observed viable disease in 34 (43.6%). On a per-patient-basis analysis, A-MRI showed significantly higher sensitivity (95% vs. 81%, P = 0.04) and higher accuracy (93% vs. 82%, P < 0.01), compared to those of CECT, while A-MRI showed comparable sensitivity (91% vs. 91%, P = 0.42) and accuracy (97% vs. 98%, P = 0.06) to that of standard liver MRI. On a per-lesion-based analysis, A-MRI exhibited significantly superior lesion detectability than that of CECT (figure of merit 0.91 vs. 0.77, P < 0.01) and comparable to that of standard liver MRI (figure of merit 0.91 vs. 0.92, P = 0.75). CONCLUSION: A-MRI exhibited higher sensitivity and diagnostic accuracy than those of CECT in the post-treatment evaluation of RC, while it showed comparable performances with standard liver MRI. A-MRI provides diagnostic added value in the follow-up of RC patients.

Discrepancies in Splenic Size Measurement: A Comparative Analysis of Ultrasound and Computed Tomography.

The accurate measurement of splenic size is essential for the diagnosis and management of various gastrointestinal and hematological conditions. While ultrasound (US) and computed tomography (CT) are widely used imaging modalities for assessing splenic size, discrepancies between their measurements have been observed in clinical practice. This study aimed to analyze the measurement differences between US and CT and identify factors influencing these differences. A retrospective analysis of 598 asymptomatic patients who underwent both abdominal US and CT was conducted. Measurements of splenic size obtained from US, axial CT, and coronal CT scans were compared, and various factors such as patient demographics, operator experience, and imaging parameters were evaluated to elucidate their impact on the measurement discrepancies. The results revealed that US consistently underestimated splenic size compared to CT. The magnitude of the discrepancy was influenced by factors such as patient age, body mass index (BMI), depth of the spleen from skin on US and that on CT, visibility of the splenic hilum on US, sonic window quality, and operator experience. This study underscores the importance of considering these factors when interpreting splenic measurements obtained from different imaging modalities in clinical practice.

Comparative study of standard and small transrectal transducers for prostate ultrasonography.

PURPOSE: The objective of this study was to evaluate pain and image quality associated with the use of two different ultrasound transducers. METHODS: Fifty healthy male participants aged 30 years or older were prospectively enrolled. All ultrasound procedures were performed using a V8 machine (Samsung Medison, Seoul, Korea) equipped with EA2-11 (conventional) and miniER7 (small-caliber) transrectal transducers, operated by a single genitourinary radiologist. To minimize bias, one group of volunteers underwent ultrasonography with the conventional transducer first, followed by the small transducer. For the remaining participants, the examinations were performed in the opposite order. Ultrasonography, including the measurement of total prostate and transitional zone volumes, was conducted in accordance with standard practice. After testing with both probes, participants were asked to rate their pain on a 10-point numerical rating scale (NRS). A radiologist then evaluated the quality of the images acquired with each probe using a 5-point numeric scale and compared the prostate volume measurements obtained by each method. RESULTS: The mean NRS scores associated with the conventional and small transducers were 4.7±1.8 and 2.7±1.2, respectively (P<0.05). The mean ultrasound image qualities from the two transducers were statistically similar (4.78 and 4.74, P>0.05). The whole prostate gland volume as measured with the conventional transducer (mean±standard deviation, 24.2±9.1 mL) was greater than the measurement (22.1±8.7 mL) obtained with the small-caliber transducer (P<0.05). However, only two of the 50 whole gland volume measurements differed by more than two standard deviations. CONCLUSION: The use of a small transrectal probe significantly reduced pain without compromising image quality.

Renal Doppler ultrasonography for predicting non-diabetic kidney disease in patients with diabetes.

PURPOSE: This study was conducted to assess the role of renal Doppler ultrasonography (US) in predicting non-diabetic kidney disease (NDKD) in patients with diabetes, using histologic findings as the reference standard. METHODS: Fifty-nine consecutive patients with diabetes who underwent renal Doppler US and native kidney biopsy were included in this retrospective, single-institutional study. Based on histologic findings, patients were classified as having diabetic nephropathy (DN) or NDKD. Renal Doppler US findings, including cortical echogenicity, corticomedullary differentiation, and the resistive index (RI), were compared between DN and NDKD. A subgroup analysis according to chronic kidney disease (CKD) status was also performed. RESULTS: Cortical echogenicity and corticomedullary differentiation showed no significant differences between DN and NDKD (P=0.887 and P>0.99, respectively), whereas the RI was significantly higher in patients with DN than in those with NDKD (P=0.032). The subgroup analysis revealed a significant difference in the RI between DN and NDKD in patients with diabetes and CKD (P=0.010), but a significant difference was not found in those without CKD (P=0.713). When limited to patients with diabetes and CKD, the RI had an area under the curve value of 0.759, sensitivity of 57.1%, specificity of 81.0%, positive likelihood ratio of 3.0, and negative LR of 0.5 for predicting NDKD, using a cutoff value of ≤0.69. CONCLUSION: Renal Doppler US may be useful in predicting NDKD in patients with diabetes and CKD.

Motion-Corrected versus Conventional Diffusion-Weighted Magnetic Resonance Imaging of the Liver Using Non-Rigid Registration.

It is challenging to overcome motion artifacts in diffusion-weighted imaging (DWI) of the abdomen. This study aimed to evaluate the image quality of motion-corrected DWI of the liver using non-rigid registration in comparison with conventional DWI (c-DWI) in patients with liver diseases. Eighty-nine patients who underwent 3-T magnetic resonance imaging (MRI) of the liver were retrospectively included. DWI was performed using c-DWI and non-rigid motion-corrected (moco) DWI was performed in addition to c-DWI. The image quality and conspicuity of hepatic focal lesions were scored using a five-point scale by two radiologists and compared between the two DWI image sets. The apparent diffusion coefficient (ADC) was measured in three regions of the liver parenchyma and in hepatic focal lesions, and compared between the two DWI image sets. Moco-DWI achieved higher scores in image quality compared to c-DWI in terms of liver edge sharpness and hepatic vessel margin delineation. The conspicuity scores of hepatic focal lesions were higher in moco-DWI. The standard deviation values of ADC of the liver parenchyma were lower in the moco-DWI than in the c-DWI. Moco-DWI using non-rigid registration showed improved overall image quality and provided more reliable ADC measurement, with an equivalent scan time, compared with c-DWI.

Computed Tomography Indicators for Differentiating Stage 1 Borderline Ovarian Tumors from Stage I Malignant Epithelial Ovarian Tumors.

Preoperative diagnosis of borderline ovarian tumors (BOTs) is of increasing concern. This study aimed to determine computed tomography (CT) features in differentiating stage 1 BOTs from stage I malignant epithelial ovarian tumors (MEOTs). A total of 170 ovarian masses (97 BOTs and 73 MEOTs) from 141 consecutive patients who underwent preoperative CT imaging were retrospectively analyzed. Two readers independently and retrospectively reviewed quantitative and qualitative CT features. Multivariate logistic analysis demonstrated that a larger tumor size (p = 0.0284 for reader 1, p = 0.0391 for reader 2) and a smaller solid component (p = 0.0007 for reader 1, p = 0.0003 for reader 2) were significantly associated with BOTs compared with MEOTs. In the subanalysis of cases with a solid component, smaller (p = 0.0092 for reader 1, p = 0.0014 for reader 2) and ill-defined (p = 0.0016 for reader 1, p = 0.0414 for reader 2) solid component was significantly associated with BOTs compared with MEOTs. Tumor size and the size and margin of the solid component were useful for differentiating stage 1 BOTs from stage 1 MEOTs on CT images.

Quantitative magnetic resonance imaging of chronic kidney disease: an experimental in vivo study using rat chronic kidney disease models.

BACKGROUND: Recent advances in magnetic resonance imaging (MRI) may allow it to be an alternative emerging tool for the non-invasive evaluation of renal parenchymal disease. PURPOSE: To validate the usefulness of quantitative multiparametric MRI protocols and suggest the suitable quantitative MR sequence protocol to evaluate parenchymal fibrosis using an animal model of chronic kidney disease (CKD) by long-term adenine intake. MATERIAL AND METHODS: In this prospective animal study, 16 male Wistar rats were analyzed and categorized into three groups. Rats in the CKD groups underwent 0.25% adenine administration for three or six weeks. Quantitative MRI protocols, including diffusion-weighted imaging (DWI), T1ρ (T1 rho), and T2* mapping were performed using a 9.4-T animal MR scanner. A semi-quantitative histopathologic analysis for renal fibrosis was conducted. Quantitative MR values measured from anatomic regions of kidneys underwent intergroup comparative analyses. RESULTS: The apparent diffusion coefficient (ADC) and T1 (T1 rho) values were significantly increased in all CKD groups. Values measured from the cortex and outer medulla showed significant intergroup differences. Total ADC values tended to increase according to periods, and T1ρ values increased in three weeks and decreased in six weeks. CONCLUSION: Quantitative MRI protocols could be a non-invasive assessment modality in the diagnosis and evaluation of CKD. Particularly, T1ρ may be a suitable MR sequence to quantitatively assess renal parenchymal fibrosis.

Association of Hepatic Steatosis Index with Nonalcoholic Fatty Liver Disease Diagnosed by Non-Enhanced CT in a Screening Population.

The noninvasive diagnosis of hepatic steatosis is of increasing concern. This study investigated the association of hepatic steatosis determined by non-enhanced CT criteria with clinical parameters in a screening population. Asymptomatic patients who underwent abdominal CT at our healthcare center were retrospectively analyzed (n = 339). Two radiologists measured the attenuation values of the liver parenchyma and spleen using non-enhanced CT images. CT criteria for hepatic steatosis were (a) absolute liver attenuation value <48 Hounsfield units (HU), (b) liver-to-spleen attenuation ratio <0.8, and (c) attenuation difference between the liver and spleen <-10. Body mass index (BMI) and hepatic steatosis index (HSI) were calculated, and laboratory findings were recorded. The association of hepatic steatosis with clinical parameters was assessed using univariate and logistic regression analyses. The presence of hepatic steatosis was significantly associated with the levels of serum fasting glucose and triglycerides, the alanine aminotransferase to aspartate aminotransferase (ALT/AST) ratio, BMI, and HSI values using any of the CT criteria. Logistic regression analysis revealed that the serum fasting glucose level and HSI were significantly associated with hepatic steatosis using criterion (a), while the ALT/AST ratio and HSI were associated with hepatic steatosis using criteria (b) and (c). The presence of hepatic steatosis on non-enhanced CT should be considered to indicate possible clinical profile abnormalities regarding metabolic syndrome.

Clinical experience of robotic myomectomy for fertility preservation using preoperative magnetic resonance imaging predictor.

OBJECTIVE: This study aimed to demonstrate the use of preoperative magnetic resonance imaging (MRI) findings to select the optimal surgical technique between single-site (SS) and multi-site (MS) robotic myomectomy based on clinical experience, for the preservation of fertility. METHODS: Ninety-eight patients who underwent SS or MS robotic myomectomy using the da Vinci® Si system after undergoing MRI were evaluated retrospectively. The correlation between preoperative MRI findings and the intraoperative or postoperative findings during robotic myomectomy for the preservation of fertility was analyzed. The reproductive outcome was investigated when the patient wished to conceive. RESULTS: The mean age of the patients was 35.68±5.04 years and 80 patients (81.6%) were nulliparous. The total diameter of myomas on MRI was 106.75±54.52 mm. The number of resected myomas was 4.31±4.39 (range, 1-27), and the total weight of resected myomas was 293.11±281.13 (range, 30-1,260) g. Myomas with high signal intensity on MRI required less time for resection. MS robotic myomectomy was performed for an increased number and total diameter of a myoma or a deep-seated myoma. Postoperatively, all patients resumed normal menstruation. Of the 15 patients who wished to conceive, 12 (80%) conceived successfully. Of these, uterine dehiscence occurred in 1 patient and 10 patients underwent an uneventful cesarean section. CONCLUSION: SS or MS robotic myomectomy can be recommended for patients who wish to conserve fertility. However, the optimal surgical technique should be selected based on preoperative MRI findings to predict an effective surgical process and the successful preservation of fertility.

Benign gallbladder diseases: Imaging techniques and tips for differentiating with malignant gallbladder diseases.

Benign gallbladder diseases usually present with intraluminal lesions and localized or diffuse wall thickening. Intraluminal lesions of the gallbladder include gallstones, cholesterol polyps, adenomas, or sludge and polypoid type of gallbladder cancer must subsequently be excluded. Polyp size, stalk width, and enhancement intensity on contrast-enhanced ultrasound and degree of diffusion restriction may help differentiate cholesterol polyps and adenomas from gallbladder cancer. Localized gallbladder wall thickening is largely due to segmental or focal gallbladder adenomyomatosis, although infiltrative cancer may present similarly. Identification of Rokitansky-Aschoff sinuses is pivotal in diagnosing adenomyomatosis. The layered pattern, degree of enhancement, and integrity of the wall are imaging clues that help discriminate innocuous thickening from gallbladder cancer. High-resolution ultrasound is especially useful for analyzing the layering of gallbladder wall. A diffusely thickened wall is frequently seen in inflammatory processes of the gallbladder. Nevertheless, it is important to check for coexistent cancer in instances of acute cholecystitis. Ultrasound used alone is limited in evaluating complicated cholecystitis and often requires complementary computed tomography. In chronic cholecystitis, preservation of a two-layered wall and weak wall enhancement are diagnostic clues for excluding malignancy. Magnetic resonance imaging in conjunction with diffusion-weighted imaging helps to differentiate xathogranulomatous cholecystitis from gallbladder cancer by identifying the presence of fat and degree of diffusion restriction. Such distinctions require a familiarity with typical imaging features of various gallbladder diseases and an understanding of the roles that assorted imaging modalities play in gallbladder evaluations.

Korean ureter length: A computed tomography-based study.

Purpose: We measured ureter length in healthy Koreans using reformatted computed tomography (ULCT) and found ways to indirectly estimate ureter length by measuring LLCT, the length between the ureteropelvic junction and the ureterovesical junction, and standing and sitting height. Materials and Methods: A total of 508 ureters of 254 healthy patients (median age, 55.0 years; 148 males and 106 females) were included in this retrospective study. ULCT, LLCT, and sitting and standing body height were measured. Results: The mean left and right ULCT were 25.2±2.2 and 25.0±2.2 cm, respectively. The mean left and right LLCT were 21.1±1.8 and 20.3±1.9 cm, respectively. Standing and sitting body height were 164.1±8.9 and 88.3±4.3 cm, respectively. Height was significantly correlated with ULCT, but this relation was not linear (r2=0.064 standing height, 0.062 sitting height). However, LLCT showed a significant linear correlation with ULCT (r2=0.485). ULCT can be estimated indirectly by the following equation: ULCT=0.823×LLCT+8.093. Conclusions: We could measure the ureteral length of healthy Koreans by ULCT. ULCT could be estimated indirectly by LLCT and standing and sitting height. Of these variables, LLCT provided the most accurate estimate of ureteral length.

Guidelines for Transrectal Ultrasonography-Guided Prostate Biopsy: Korean Society of Urogenital Radiology Consensus Statement for Patient Preparation, Standard Technique, and Biopsy-Related Pain Management.

The Korean Society of Urogenital Radiology (KSUR) aimed to present a consensus statement for patient preparation, standard technique, and pain management in relation to transrectal ultrasound-guided prostate biopsy (TRUS-Bx) to reduce the variability in TRUS-Bx methodologies and suggest a nationwide guideline. The KSUR guideline development subcommittee constructed questionnaires assessing prebiopsy anticoagulation, the cleansing enema, antimicrobial prophylaxis, local anesthesia methods such as periprostatic neurovascular bundle block (PNB) or intrarectal lidocaine gel application (IRLA), opioid usage, and the number of biopsy cores and length and diameter of the biopsy needle. The survey was conducted using an Internet-based platform, and responses were solicited from the 90 members registered on the KSUR mailing list as of 2018. A comprehensive search of relevant literature from Medline database was conducted. The strength of each recommendation was graded on the basis of the level of evidence. Among the 90 registered members, 29 doctors (32.2%) responded to this online survey. Most KSUR members stopped anticoagulants (100%) and antiplatelets (76%) one week before the procedure. All respondents performed a cleansing enema before TRUS-Bx. Approximately 86% of respondents administered prophylactic antibiotics before TRUS-Bx. The most frequently used antibiotics were third-generation cephalosporins. PNB was the most widely used pain control method, followed by a combination of PNB plus IRLA. Opioids were rarely used (6.8%), and they were used only as an adjunctive pain management approach during TRUS-Bx. The KSUR members mainly chose the 12-core biopsy method (89.7%) and 18G 16-mm or 22-mm (96.5%) needles. The KSUR recommends the 12-core biopsy scheme with PNB with or without IRLA as the standard protocol for TRUS-Bx. Anticoagulants and antiplatelet agents should be discontinued at least 5 days prior to the procedure, and antibiotic prophylaxis is highly recommended to prevent infectious complications. Glycerin cleansing enemas and administration of opioid analogues before the procedure could be helpful in some situations. The choice of biopsy needle is dependent on the practitioners' situation and preferences.

Prediction of Necrotizing Pancreatitis on Early CT Based on the Revised Atlanta Classification.

Purpose: To investigate the clinical and CT features at admission to predict the progression to necrotizing pancreatitis (NP) in patients initially diagnosed with interstitial edematous pancreatitis (IEP). Materials and Methods: Patients with IEP who underwent contrast-enhanced CT at admission and follow-up CT (< 14 days) were included (n = 178). Two radiologists performed a consensus review of follow-up CT scans and diagnosed the type of acute pancreatitis as IEP or NP. Laboratory findings at admission were recorded. Clinical, CT, and laboratory findings were compared between the IEP-IEP group and IEP-NP group using the chi-square test and the t-test. Multivariate analysis was also performed. Results: There were 112 and 66 patients in the IEP-IEP and the IEP-NP groups, respectively. The proportion of patients with alcohol etiology was significantly larger in the IEP-NP group. Among the CT findings, the presence of peripancreatic fluid and heterogeneous parenchymal enhancement were more frequently observed in the IEP-NP group. Among the laboratory variables, serum C-reactive protein levels and white blood cell counts were significantly higher in the IEP-NP group. Multivariate analysis revealed that the presence of peripancreatic fluid and heterogeneous parenchymal enhancement were significant findings distinguishing the two groups. Conclusion: CT findings, such as the presence of peripancreatic fluid and heterogeneous pancreatic parenchymal enhancement, may be helpful in predicting the progression to NP in patients initially diagnosed with IEP.

Assessing significant fibrosis using imaging-based elastography in chronic hepatitis B patients: Pilot study.

BACKGROUND: Accurate detection of significant fibrosis (fibrosis stage 2 or higher on the METAVIR scale) is important especially for chronic hepatitis B (CHB) patients with high viral loads but with normal or mildly elevated alanine aminotransferase (ALT) levels because the presence of significant fibrosis is accepted as the indication for antiviral treatment. Liver biopsy is the reference standard for diagnosing significant fibrosis, but it is an invasive procedure. Consequently, noninvasive imaging-based measurements, such as magnetic resonance elastography (MRE) or two-dimensional shear-wave elastography (2D-SWE), have been proposed for the quantitative assessment of liver fibrosis. AIM: To explore MRE and 2D-SWE to identify fibrosis stage, and to compare their performance with that of serum-based indices. METHODS: The study enrolled 63 treatment-naïve CHB patients with high viral loads but with normal or mildly elevated ALT levels who underwent liver biopsy before a decision was made to initiate antiviral therapy. MRE and 2D-SWE were performed, and serum-based indices, such as FIB-4 and aspartate transaminase to platelet ratio index (APRI), were calculated. The diagnostic performances of MRE, 2D-SWE, FIB-4, and APRI for assessing significant fibrosis (≥ F2) and cirrhosis (F4) were evaluated with liver histology as the reference standard, using receiver operating characteristic analyses. RESULTS: The liver fibrosis stage was F0/F1 in 19, F2 in 14, F3 in 14, and F4 in 16 patients, respectively. MRE significantly discriminated F2 from F0/1 (P = 0.022), whereas 2D-SWE showed a broad overlap in distinguishing those stages. MRE showed a higher correlation coefficient value with fibrosis stage than 2D-SWE with fibrosis stage (0.869 vs 0.649, Spearman test; P < 0.001). Multivariate linear regression analyses showed that fibrosis stage was the only factor affecting the values of MRE (P < 0.001), whereas body mass index (P = 0.042) and fibrosis stage (P < 0.001) were independent factors affecting 2D-SWE values. MRE performance for diagnosing significant fibrosis was better [area under the curve (AUC) = 0.906, positive predictive value (PPV) 97.3%, negative predictive value (NPV) 69.2%] than that of FIB-4 (AUC = 0.697, P = 0.002) and APRI (AUC = 0.717, P = 0.010), whereas the performance of 2D-SWE (AUC = 0.843, PPV 86%, NPV 65%) was not significantly different from that of FIB-4 or APRI. CONCLUSION: Compared to SWE, MRE might be more precise non-invasive assessment for depicting significant fibrosis and for making-decision to initiate antiviral-therapy in treatment-naïve CHB patients with normal or mildly-elevated ALT levels.

Shrinkage of hepatocellular carcinoma after radiofrequency ablation following transcatheter arterial chemoembolization: Analysis of contributing factors.

OBJECTIVE: This study was conducted to investigate tumor shrinkage and influencing factors in patients with hepatocellular carcinoma (HCC) from radiofrequency (RF) ablation following transcatheter arterial chemoembolization (TACE). METHODS: A total of 222 patients underwent combined sequential treatment of TACE and RF ablation for HCC at our institution between 2008 and 2014. Of those, 86 patients (men, 68; women, 18) who achieved compact iodized oil tagging and complete ablation were included for this retrospective study. We measured three-dimensional tumor diameters and calculated tumor volumes on pre-treatment CT/MRI and follow-up CT scans performed post-TACE, post-ablation, and 1 month post-treatment, respectively. To compare periodically generated tumor diameters and volumes, repeated measures analysis of variance (ANOVA) was applied. Multiple linear regression analysis was performed to identify factors impacting tumor shrinkage after RF ablation. RESULTS: Diameters and volumes of HCCs declined significantly in the immediate aftermath of RF ablation (i.e., between post-TACE and post-ablation CT scans) (p < 0.001, for both). Mean reduction rates in tumor diameter and volume immediately after RF ablation were 18.2 ± 9.1% and 44.4 ± 14.6%, respectively. Of note, tumors of left hepatic lobe and in subphrenic or perivascular locations showed lower rates of post-ablative volume reduction than those in counterpart locations (p = 0.002, 0.046, 0.024, respectively). Tumor size and liver function did not influence tumor shrinkage after RF ablation. CONCLUSION: In patients with HCC, significant tumor shrinkage occurs immediately after RF ablation. The degree of shrinkage in response to ablative treatment seems to vary by tumor location.

Low-Tube-Voltage CT Urography Using Low-Concentration-Iodine Contrast Media and Iterative Reconstruction: A Multi-Institutional Randomized Controlled Trial for Comparison with Conventional CT Urography.

Objective: To compare the image quality of low-tube-voltage and low-iodine-concentration-contrast-medium (LVLC) computed tomography urography (CTU) with iterative reconstruction (IR) with that of conventional CTU. Materials and Methods: This prospective, multi-institutional, randomized controlled trial was performed at 16 hospitals using CT scanners from various vendors. Patients were randomly assigned to the following groups: 1) the LVLC-CTU (80 kVp and 240 mgI/mL) with IR group and 2) the conventional CTU (120 kVp and 350 mgI/mL) with filtered-back projection group. The overall diagnostic acceptability, sharpness, and noise were assessed. Additionally, the mean attenuation, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and figure of merit (FOM) in the urinary tract were evaluated. Results: The study included 299 patients (LVLC-CTU group: 150 patients; conventional CTU group: 149 patients). The LVLC-CTU group had a significantly lower effective radiation dose (5.73 ± 4.04 vs. 8.43 ± 4.38 mSv) compared to the conventional CTU group. LVLC-CTU showed at least standard diagnostic acceptability (score ≥ 3), but it was non-inferior when compared to conventional CTU. The mean attenuation value, mean SNR, CNR, and FOM in all pre-defined segments of the urinary tract were significantly higher in the LVLC-CTU group than in the conventional CTU group. Conclusion: The diagnostic acceptability and quantitative image quality of LVLC-CTU with IR are not inferior to those of conventional CTU. Additionally, LVLC-CTU with IR is beneficial because both radiation exposure and total iodine load are reduced.

Multiparametric MR imaging of peripheral zone prostate cancer: effect of postbiopsy hemorrhage on cancer detection according to Gleason score and tumour volume.

OBJECTIVE: To evaluate effect of postbiopsy hemorrhage on detection of peripheral zone (PZ) prostate cancer by multiparametric MR imaging according to Gleason score and tumor volume. METHODS: This retrospective study included 54 biopsy-proven prostate cancer patients (median age, 67.0 years) who underwent multiparametric MR imaging. Two independent readers evaluated each sextant of the PZ using the PI-RADS v2. One reader recorded the presence or absence of hemorrhage per sextant on T1 weighted MR images. Areas under the receiver operating characteristic curves (AUCs) were used to evaluate cancer detection accuracy. RESULTS: Postbiopsy hemorrhage was noted in 122 (37.7%) of 324 sextants of all patients. There was no significant difference in the AUC for detection of cancer with Gleason score ≥3 + 4 or volume ≥0.5 ml between sextants with and without hemorrhage (with hemorrhage, reader 1, 0.83 for Gleason score ≥3 + 4, 0.84 for tumor volume ≥0.5 ml; reader 2, 0.74 for Gleason score ≥3 + 4, 0.77 for tumor volume ≥0.5 ml; without hemorrhage, reader 1, 0.86 for Gleason score ≥3 + 4, 0.88 for tumor volume ≥0.5 ml; reader 2, 0.79 for Gleason score ≥3 + 4, 0.83 for tumor volume ≥0.5 ml; p > 0.2 for all). CONCLUSION: Postbiopsy hemorrhage did not negatively affect the detection of clinically significant PZ prostate cancer on multiparametric MR imaging. Advances in knowledge: Under influence of postbiopsy hemorrhage, multiparametric MR can be useful for the detection of clinically significant PZ prostate cancer.

Estimation of hepatic fat fraction using modified Dixon magnetic resonance imaging techniques: effect of liver cirrhosis.

PURPOSE: To evaluate modified Dixon MRI techniques in hepatic fat estimation and to assess the effect of cirrhosis. METHODS: 235 patients who underwent liver MRI were included. Correlation between modified Dixon techniques with MRS was assessed. Accuracy of MR techniques in hepatic fat estimation was calculated, and the result was compared between patients with/without liver cirrhosis. RESULTS: Correlation between modified Dixon and MRS was better in group without liver cirrhosis, and accuracy of modified Dixon method was higher in group without liver cirrhosis. CONCLUSIONS: Modified Dixon techniques estimate hepatic fat fraction noninvasively, but the result can be influenced by the presence of liver cirrhosis.

Comparison of Nonspherical Polyvinyl Alcohol Particles and Microspheres for Prostatic Arterial Embolization in Patients with Benign Prostatic Hyperplasia.

PURPOSE: To report early results following prostatic artery embolization (PAE) and compare outcomes between nonspherical polyvinyl alcohol (PVA) particles and microspheres to treat lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). METHODS: PAE was performed in nine patients (mean age: 78.1 years) with symptomatic BPH. Embolization was performed using nonspherical PVA particles (250-355 µm) in four patients and microspheres (300-500 µm) in five patients. RESULTS: PAE was technically successful in all nine patients (100%). During a mean follow-up of 10.1 months, improvements in mean International Prostate Symptom Score (IPSS), Quality of Life (QoL), prostatic volume (total volume and transition zone), and peak urinary flow (Qmax) were 9.8 points, 2.3 points, 28.1 mL, 17.8 mL, and 4.5 mL/s, respectively. Clinical success was obtained in seven of nine patients (78%). Patients in the microsphere group showed greater improvement in IPSS, QoL, prostatic volume, and Qmax compared to patients in the nonspherical PVA particle group. However, significant difference was noted only in the prostatic volume. CONCLUSION: PAE is a feasible, effective, and safe treatment option for BPH with LUTS. Use of microspheres showed greater prostatic volume reduction compared to nonspherical PVA particles.