Deuk Jae Sung

Detectability of low and intermediate or high risk prostate cancer with combined T2-weighted and diffusion-weighted MRI

AbstractObjectivesTo evaluate the incremental value of diffusion-weighted imaging (DWI) in combination with T2-weighted imaging to detect low (Gleason score, ≤ 6) and intermediate or high risk (Gleason score, ≥ 7) prostate cancer.MethodsFifty-one patients who underwent MRI before prostatectomy were evaluated. Two readers independently scored the probability of tumour in eight regions of prostate on T2-weighted images (T2WI) and T2WI combined with apparent diffusion coefficient (ADC) maps. Data were divided into two groups—low risk and intermediate or high risk prostate cancer—and correlated with histopathological results. Diagnostic performance parameters, areas under the receiver-operating characteristic curve (AUCs) and interreader agreement were calculated.ResultsFor both readers, AUCs of combined T2WI and ADC maps were greater than those of T2WI in intermediate or high risk (reader 1, 0.887 vs. 0.859; reader 2, 0.732 vs 0.662, P < 0.05) prostate cancers, but not in low risk (reader 1, 0.719 vs 0.725; reader 2, 0.685 vs. 0.680, P > 0.05) prostate cancers. Weighted κ value of combined T2WI and ADC maps was 0.689.ConclusionsThe addition of DWI to T2-weighted imaging improves the accuracy of detecting intermediate or high risk prostate cancers, but not for low risk prostate cancer detection.Key Points• Gleason scores influence diagnostic performance of MRI for prostate cancer detection. • Addition of DWI does not improve low risk prostate cancer detection. • Combined T2WI and DWI may help select intermediate or high risk patients.

Bisphenol A inhibits penile erection via alteration of histology in the rabbit

Despite extensive research into the toxicity of bisphenol A (BPA), no report of its effect on erectile function exists. We performed this study to investigate the effect of BPA on erectile function. New Zealand white rabbits were treated intraperitoneally with 150 mg/kg of BPA every other day for 12 days (cumulative dose of 900 mg/kg). Four and 8 weeks after administration of BPA, the contractions and relaxation of cavernosal tissue strips were significantly suppressed in the BPA-treated animals compared to the control animals. Histologically, thickening of tunica albuginea, subtunical deposition of fat and decreased sinusoidal space with consequent increase of trabecular smooth muscle content were observed in the BPA-treated animals. These results suggest that xenoestrogen BPA may affect the erectile function through evident histological changes of the penis.

The Incidence and Anatomy of Accessory Pudendal Arteries as Depicted on Multidetector-Row CT Angiography: Clinical Implications of Preoperative Evaluation for Laparoscopic and Robot-Assisted Radical Prostatectomy

Objective To help preserve accessory pudendal arteries (APAs) and to ensure optimal postoperative sexual function after a laparoscopic or robot-assisted radical prostatectomy, we have evaluated the incidence of APAs as detected on multidetector-row CT (MDCT) angiography and have provided a detailed anatomical description. Materials and Methods The distribution of APAs was evaluated in 121 consecutive male patients between February 2006 and July 2007 who underwent 64-channel MDCT angiography of the lower extremities. We defined an APA as any artery located within the periprostatic region running parallel to the dorsal vascular complex. We also subclassified APAs into lateral and apical APAs. Two radiologists retrospectively evaluated the origin, course and number of APAs; the final APA subclassification based on MDCT angiography source data was determined by consensus. Results We identified 44 APAs in 36 of 121 patients (30%). Two distinct varieties of APAs were identified. Thirty-three APAs (75%) coursed near the anterolateral region of the prostatic apex, termed apical APAs. The remaining 11 APAs (25%) coursed along the lateral aspect of the prostate, termed lateral APAs. All APAs originated from the internal obturator artery and iliac artery or a branch of the iliac artery such as the inferior vesical artery. The majority of apical APAs arose from the internal obturator artery (84%). Seven patients (19%) had multiple APAs. Conclusion APAs are more frequently detected by the use of MDCT angiography than as suggested by previous surgical studies. The identification of APAs on MDCT angiography may provide useful information for the surgical preservation of APAs during a laparoscopic or robot-assisted radical prostatectomy.

Chemotherapy-induced Focal Hepatopathy in Patients with Gastrointestinal Malignancy: Gadoxetic Acid–enhanced and Diffusion-weighted MR Imaging with Clinical-Pathologic Correlation

PURPOSE To retrospectively evaluate findings of chemotherapy-induced focal hepatopathy (CIFH) on gadoxetic acid-enhanced magnetic resonance (MR) and diffusion-weighted (DW) images and to determine imaging features that are most helpful in differentiating CIFH from metastasis. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and informed consent was waived. MR images, including DW images and gadoxetic acid-enhanced images, from 12 patients (four men, eight women; age range, 25-64 years) with 15 CIFHs were reviewed independently and in consensus by two radiologists and were compared with those obtained in 20 control patients (12 men, eight women; age range, 32-84 years) with 30 hepatic metastasis who were matched for tumor size, primary organ, and chemotherapy regimen. Interobserver agreement was assessed with κ statistics, and univariate analysis was performed for comparisons. For quantitative analyses, apparent diffusion coefficients (ADCs) and lesion-to-liver contrast ratios (CRs) were measured. Histopathologic examinations were performed for CIFHs. RESULTS Histopathologic examination revealed that the development of CIFHs was attributable to accentuated manifestations of sinusoidal obstruction syndrome. Interobserver agreement was excellent (κ > 0.85). An ill-defined margin on hepatobiliary phase (HBP) images was the most discriminating independent variable in the differentiation of CIFH from metastasis (odds ratio, 16; P = .009). ADC and CR values in CIFH group were significantly higher than those in metastasis group (P < .001 and P = .041). CONCLUSION CIFH should be considered a mimicker of metastasis in patients with gastrointestinal malignancy during chemotherapy. CIFH can be differentiated from metastasis on the basis of gadoxetic acid-enhanced MR and DW imaging findings; an ill-defined margin on HBP images was especially characteristic.

Magnetic Resonance Urethrography to Assess Obliterative Posterior Urethral Stricture: Comparison to Conventional Retrograde Urethrography With Voiding Cystourethrography

PURPOSE We prospectively evaluated magnetic resonance urethrography for depicting obliterative posterior urethral stricture. MATERIALS AND METHODS A total of 25 men with a mean age of 48.7 years (range 21 to 72) with complete posterior urethral stricture were studied preoperatively with axial and sagittal turbo spin-echo T2, sagittal T1 and contrast enhanced sagittal T1-weighted images. Of the 25 patients 22 underwent conventional retrograde urethrography with voiding cystourethrography. For magnetic resonance urethrography aseptic lubricant was infused through the external urethral meatus to dilate the distal urethra up to the stricture. Each imaging result was compared with a surgical specimen or a description of the surgical findings. Measurement errors were analyzed using the Wilcoxon signed rank test. The relationship between true and measured stricture length was evaluated by linear regression analysis. RESULTS Based on magnetic resonance urethrography findings 2 patients with a less than 1 cm stricture were treated with internal urethrotomy, 21 with a more than 1 cm stricture underwent open urethroplasty and 2 with prostatic displacement and a 4 cm stricture needed the combined perineal and transpubic approach. The mean +/- SD measurement error on magnetic resonance urethrography imaging was significantly lower than that on conventional retrograde urethrography combined with voiding cystourethrography (0.4 +/- 0.4 vs 1.4 +/- 1.1 cm, p <0.001). Linear regression analysis showed a stronger linear relationship between magnetic resonance urethrography and surgical measurement (r(2) = 0.62, p <0.01). CONCLUSIONS Magnetic resonance urethrography is more effective for evaluating obliterative posterior urethral stricture than retrograde urethrography combined with voiding cystourethrography.

Contrast-Induced Nephropathy in Patients Undergoing Intravenous Contrast-Enhanced Computed Tomography in Korea: A Multi-Institutional Study in 101487 Patients

Objective To evaluate the prevalence of known risk factors for contrast-induced nephropathy (CIN) and their association with the actual occurrence of CIN in patients undergoing intravenous contrast-enhanced computed tomography (CECT) in Korea. Materials and Methods Patients who underwent CECT in 2008 were identified in the electronic medical records of 16 tertiary hospitals of Korea. Data on demographics, comorbidities, prescriptions and laboratory test results of patients were collected following a standard data extraction protocol. The baseline renal function was assessed using the estimated glomerular filtration rate (eGFR). We identified the prevalence of risk factors along the eGFR strata and evaluated their influence on the incidence of CIN, defined as a 0.5 mg/dL or 25% increase in serum creatinine after CECT. Results Of 432425 CECT examinations in 272136 patients, 140838 examinations in 101487 patients met the eligibility criteria for analysis. The mean age of the participants was 57.9 ± 15.5 years; 25.1% of the patients were older than 70 years. The prevalence of diabetes mellitus was 11.9%, of hypertension 13.7%, of gout 0.55% and of heart failure was 1.7%. Preventive measures were used in 40238 CECT examinations (28.6%). The prevalence of risk factors and use of preventive measures increased as the renal function became worse. A CIN was occurred after 3103 (2.2%) CECT examinations, revealing a significant association with decreased eGFR, diabetes mellitus, and congestive heart failure after adjustment. Conclusion Risk factors for CIN are prevalent among the patients undergoing CECT. Preventive measures were seemingly underutilized and a system is needed to improve preventive care.

Hepatic Parenchymal Heterogeneity on Contrast-enhanced CT Scans Following Oxaliplatin-based Chemotherapy: Natural History and Association with Clinical Evidence of Sinusoidal Obstruction Syndrome

PURPOSE To evaluate the natural history and contrast material-enhanced computed tomographic (CT) features of postoxaliplatin heterogeneity of liver parenchyma (POHL) and to investigate the association of POHL with clinical factors and biomarkers of sinusoidal obstruction syndrome (SOS). MATERIALS AND METHODS The retrospective study was approved by the institutional review board, and informed consent was waived. Two hundred seventy patients (159 men, 111 women; age range, 31-92 years) who underwent oxaliplatin-based chemotherapy (OBC) and serial contrast-enhanced CT were consecutively registered. POHL severity was independently scored by two abdominal imagers, who were blinded to the clinical data, using a six-point scale (POHL presence, ≥4), followed by a consensus review. Complete radiologic remission was determined by consensus on the disappearance of heterogeneity on CT images. The association of POHL severity score with CT-based quantitative (ie, change in spleen size and blood-free hepatic parenchymal attenuation) and laboratory values (ie, aspartate aminotransferase, alanine transaminase, and platelet count), as well as time to complete radiologic remission, were evaluated with the Spearman rank test. Multivariate analysis was performed to determine the association between clinical factors of SOS (ie, age, sex, number of OBC sessions, chemotherapy regimen, bevacizumab use, and presence of concomitant hepatic metastasis) and POHL development. RESULTS Interobserver agreement was excellent (κ = 0.90). POHL was present in 167 (61.9%) of 270 patients, and the number of OBC sessions was significantly associated with POHL development (odds ratio, 1.138; 95% confidence interval: 1.039, 1.245; P = .005). POHL severity score was correlated with quantitative CT and laboratory values (P < .05 for all statistical analysis). Peripheral distribution (103 of 167, 61.7%) and right lobar predominance (103 of 165, 62.4%) were the most common POHL features. The mean time to complete radiologic remission, which was correlated with POHL severity score, was 82.5 days ± 68.8 after OBC discontinuation. CONCLUSION POHL development is associated with increased number of OBC sessions, and POHL severity was correlated with various biomarkers of SOS.

The use of everolimus to target carcinogenic pathways in a patient with renal cell carcinoma and tuberous sclerosis complex: a case report

IntroductionAn increased understanding of the genetic pathways involved in renal cell carcinoma has resulted in the development of various drugs that target relevant signaling cascades for the specific treatment of this disease. However, no validated predictive markers have been identified to guide the decision whether patients should receive vascular endothelial growth factor–targeted therapy or mammalian target of rapamycin–targeted therapy. We present what is, to the best of our knowledge, the first case of renal cell carcinoma in a patient with tuberous sclerosis complex who was successfully treated with everolimus.Case presentationThe patient was a 49-year-old Korean woman with tuberous sclerosis complex and recurrent renal cell carcinoma. The patient was treated with the tyrosine kinase inhibitor sunitinib followed by the mammalian target of rapamycin inhibitor everolimus. This treatment resulted in a prolonged response and significant clinical benefit. Notably, everolimus ameliorated the symptoms related not only to renal cell carcinoma but also to tuberous sclerosis complex.ConclusionThis case provides a rationale for the use of everolimus as first-line treatment for this specific patient population in order to target the correct pathway involved in carcinogenesis.

The optimal timing of post-prostate biopsy magnetic resonance imaging to guide nerve-sparing surgery

The goal of our study was to evaluate the impact of the interval between prostate biopsy and magnetic resonance imaging (MRI) on the accuracy of simple tumor localization, which is essential information that enables nerve-sparing surgery. We also sought to determine the optimal timing of a post-biopsy MRI. A total of 184 patients who had undergone MRI before radical prostatectomy at an institution without a predetermined schedule for MRI after a prostate biopsy were enrolled. The mean interval from the biopsy to the MRI was 30.8 ± 18.6 days. The accuracy of the MRI for simplified tumor location (right, left, bilateral and none) was 44.6%. In the group with discordant pathologic and MRI findings, the most common reason recorded was ‘MRI predicted a unilateral lesion, but pathology revealed bilateral lesions’ (58.3%), followed by ‘MRI predicted no lesion, but pathology revealed the presence of a lesion’ (32.0%). Multivariable analysis showed that the discordant group had a shorter interval (25.0 ± 14.3 vs 38.1 ± 20.6 days, P < 0.01) preceding the MRI and a higher rate of hemorrhage as observed by MRI (80.4% vs 54.8%, P < 0.01) in comparison with the accordant group. In receiver operating characteristics analysis, the area under the curve of the MRI interval in accurate prediction of the tumor location was 0.707 (P < 0.001). At the MRI intervals cutoff of 28.5 days, the sensitivity was 73.2% and the specificity was 63.7%. When the MRI was performed within 28 days, the accumulated accuracy was only 26.1% (23/88); however, when it was performed after 28 days, the reversely accumulated accuracy was 61.5% (59/96). These data support a waiting period of at least 4 weeks after a biopsy before performing an MRI for the purposes of surgical refinement.

Biliary phytobezoar resulting in intestinal obstruction.

Phytobezoar is the most common type of bezoar. It is composed of indigestible vegetable matter and is usually found in the stomach. Biliary phytobezoar is extremely rare and difficult to diagnose preoperatively. The pathogenesis is not clear, and there have been only a few reports of biliary bezoars associated with sphincteric impairment at the ampulla of Vater. Here, we present a report of biliary bezoar that resulted in jejunal obstruction. We were unable to identify the bezoar in the extrahepatic bile duct until it obstructed the small bowel lumen. To our knowledge, this is the first report of small bowel obstruction resulting from migration of a biliary bezoar.