Effect of Bone Resorption Inhibitors on Serum Cholesterol Level and Fracture Risk in Osteoporosis: Randomized Comparative Study Between Minodronic Acid and Raloxifene.

The positive link between osteoporosis and hypercholesterolemia has been documented, and bone resorption inhibitors, such as nitrogen-containing bisphosphonates (N-BP) and selective estrogen receptor modulators (SERMs), are known to reduce serum cholesterol levels. However, the relationship between the baseline cholesterol level and incident fracture rate under the treatment using the bone resorption inhibitors has not been documented. We investigated the relation between vertebral fracture incident and the baseline cholesterol levels and cholesterol-lowering effect of N-BP and SERM in osteoporosis through a prospective randomized open-label study design. Patients with osteoporosis (n = 3986) were allocated into two groups based on the drug used for treatment: minodronic acid (MIN) (n = 1624) as an N-BP and raloxifene (RLX) as an SERM (n = 1623). Serum levels of cholesterol and incidence of vertebral fracture were monitored for 2 years. The vertebral fracture rates between the two groups were compared using the pre-specified stratification factors. The patients receiving MIN with baseline low-density lipoprotein (LDL)-cholesterol level of ≥ 140 mg/dL, high-density lipoprotein cholesterol level < 40 mg/dL, age group of ≥ 75 years, and T score of BMD ≥ -3 SD had significantly lower vertebral fracture rates than those receiving RLX (incidence rate ratios (IRR) 0.45 [95% confidence interval (CI) 0.30 0.75, p = 0.001], 0.25 [95% CI 0.09 0.65, p = 0.005], 0.71 [95% CI 0.56 0.91, p = 0.006], 0.47 [95% CI 0.30 0.75, p = 0.0012], respectively). The cholesterol-lowering effect was stronger in the RLX group than in the MIN group, regardless of prior statin use. These results indicated that MIN treatment was more effective in reducing fracture risk in patients with higher LDL cholesterol levels, although its cholesterol-lowering ability was lesser than the RLX treatment.Trial registration University Hospital Medical Information Network-Clinical Trials Registry (UMIN-CTR), No. UMIN000005433; date: April 13, 2011.

Abaloparatide Increases Lumbar Spine and Hip BMD in Japanese Patients With Osteoporosis: The Phase 3 ACTIVE-J Study.

CONTEXT: Abaloparatide reduced fracture risk in postmenopausal women with osteoporosis in the Abaloparatide Comparator Trial In Vertebral Endpoints (ACTIVE). Its effect in Japanese patients remains unexamined. OBJECTIVE: This work aimed to determine the efficacy and safety of abaloparatide in increasing bone mineral density (BMD) in Japanese patients with osteoporosis at high fracture risk. METHODS: This was a randomized, double-blind, placebo-controlled study conducted in Japan. Postmenopausal women and men with osteoporosis with high fracture risk were given daily subcutaneous 80 µg abaloparatide or placebo for 78 weeks (18 months). The primary end point was percentage change in lumbar spine (LS) BMD from baseline at the last visit. Secondary end points included time-course changes in LS, total hip (TH), and femoral neck (FN) BMDs and bone turnover markers, and cumulative number of fractures. RESULTS: Abaloparatide increased LS, TH, and FN BMDs (mean [95% CI]) by 12.5% (10.3%-14.8%; P < .001), 4.3% (3.3%-5.3%), and 4.3% (2.9%-5.6%), respectively, vs placebo. Serum procollagen type I N-terminal propeptide increased rapidly to ~ 140% above baseline at 6 weeks and gradually decreased but was approximately 25% higher than baseline at 78 weeks. Serum carboxy-terminal cross-linking telopeptide of type I collagen gradually increased to 50% above baseline at 24 weeks and decreased gradually to the placebo-group level from 60 weeks. Four vertebrae of 3 participants in the placebo group, but none in the abaloparatide group, developed new vertebral fractures. The safety profile was similar to that in the ACTIVE study. CONCLUSION: In Japanese patients with postmenopausal and male osteoporosis with high fracture risk, abaloparatide for 78 weeks robustly increased LS, TH, and FN BMDs, suggesting a similar efficacy in Japanese patients vs the ACTIVE study population.

Clinical application of single-shot echo-planar diffusion-weighted imaging with compressed SENSE in prostate MRI at 3T: preliminary experience.

OBJECTIVES: Image quality (IQ) of diffusion-weighted imaging (DWI) with single-shot echo-planar imaging (ssEPI) suffers from low signal-to-noise ratio (SNR) in high b-value acquisitions. Compressed SENSE (C-SENSE), which combines SENSE with compressed sensing, enables SNR to be improved by reducing noise. The aim of this study was to compare IQ and prostate cancer (PC) detectability between DWI with ssEPI using SENSE (EPIS) and using C-SENSE (EPICS). MATERIALS AND METHODS: Twenty-five patients with pathologically proven PC underwent multi-parametric magnetic resonance imaging at 3T. DW images acquired with EPIS and EPICS were assessed for the following: lesion conspicuity (LC), SNR, contrast-to-noise ratio (CNR), mean and standard deviation (SD) of apparent diffusion coefficient (ADC) of lesion (lADCm and lADCsd), coefficient of variation of lesion ADC (lADCcv), and mean ADC of benign prostate (bADCm). RESULTS: LC were comparable between EPIS and EPICS (p > 0.050), and SNR and CNR were significantly higher in EPICS than EPIS (p = 0.001 and p < 0.001). In both EPIS and EPICS, lADCm was significantly lower than bADCm (p < 0.001). In addition, lADCcv was significantly lower in EPICS than in EPIS (p < 0.001). CONCLUSION: Compared with EPIS, EPICS has improved IQ and comparable diagnostic performance in PC.

Clinical impact of ultra-high b-value (3000 s/mm2) diffusion-weighted magnetic resonance imaging in prostate cancer at 3T: comparison with b-value of 2000 s/mm2.

OBJECTIVE: High b-value diffusion-weighted imaging (hDWI) with a b-value of 2000 s/mm2 provides insufficient image contrast between benign and malignant tissues and an overlap of apparent diffusion coefficient (ADC) between Gleason grades (GG) in prostate cancer (PC). We compared image quality, PC detectability, and discrimination ability for PC aggressiveness between ultra-high b-value DWI (uhDWI) of 3000 s/mm2 and hDWI. METHODS: The subjects were 49 patients with PC who underwent 3T multiparametric MRI. Single-shot echo-planar DWI was acquired with b-values of 0, 2000, and 3000 s/mm2. Anatomical distortion of prostate (AD), signal intensity of benign prostate (PSI), and lesion conspicuity score (LCS) were assessed using a 4-point scale; and signal-to-noise ratio, contrast-to-noise ratio, and mean ADC (×10-3 mm2/s) of lesion (lADC) and surrounding benign region (bADC) were measured. RESULTS: PSI was significantly lower in uhDWI than in hDWI (p < 0.001). AD, LCS, signal-to-noise ratio, and contrast-to-noise ratio were comparable between uhDWI and hDWI (all p > 0.05). In contrast, lADC was significantly lower than bADC in both uhDWI and hDWI (both p < 0.001). In comparison of lADC between tumors of ≤GG2 and those of ≥GG3, both uhDWI and hDWI showed significant difference (p = 0.007 and p = 0.021, respectively). AUC for separating tumors of ≤GG2 from those of ≥GG3 was 0.731 in hDWI and 0.699 in uhDWI (p = 0.161). CONCLUSION: uhDWI suppressed background signal better than hDWI, but did not contribute to increased diagnostic performance in PC. ADVANCES IN KNOWLEDGE: Compared with hDWI, uhDWI could not contribute to increased diagnostic performance in PC.

Quantitative diffusion-weighted imaging and dynamic contrast-enhanced MR imaging for assessment of tumor aggressiveness in prostate cancer at 3T.

PURPOSE: To compare diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MR imaging (DCE-MRI) for characterization of prostate cancer (PC). METHODS: 104 PC patients who underwent prostate multiparametric MRI at 3T including DWI and DCE-MRI before MRI-guided biopsy or radical prostatectomy. Apparent diffusion coefficient (ADC) with histogram analysis (mean, 0-25th percentile, skewness, and kurtosis), intravoxel incoherent motion model including D and f; stretched exponential model including distributed diffusion coefficient (DDC) and a; and permeability parameters including Ktrans, Kep, and Ve were obtained from a region of interest placed on the dominant tumor of each patient. RESULTS: ADCmean, ADC0-25, D, DDC, and Ve were significantly lower and Kep was significantly higher in GS ≥ 3 + 4 tumors (n = 89) than in GS = 3 + 3 tumors (n = 15), and also in GS ≥ 4 + 3 tumors (n = 57) than in GS ≤ 3 + 4 tumors (n = 47) (P < 0.001 to P = 0.040). f was significantly lower in GS ≥ 4 + 3 tumors than in GS ≤ 3 + 4 tumors (P = 0.022), but there was no significant difference between GS = 3 + 3 tumors and GS ≥ 3 + 4 tumors, or between the remaining metrics in both comparisons. In metrics with area under the curve (AUC) >0.80, there was a significant difference in AUC between ADC0-25 and D, and DDC for separating GS ≤ 3 + 4 tumors from GS ≥ 4 + 3 tumors (P = 0.040 and P = 0.022, respectively). There were no significant differences between metrics with AUC > 0.80 for separating GS = 3 + 3 tumors from GS ≥ 3 + 4 tumors. ADC0-25 had the highest correlation with Gleason grade (ρ = -0.625, P < 0.001). CONCLUSIONS: DWI and DCE-MRI showed no apparent clinical superiority of non-Gaussian models or permeability MRI over the mono-exponential model for assessment of tumor aggressiveness in PC.

Comparison of Biparametric and Multiparametric MRI for Clinically Significant Prostate Cancer Detection With PI-RADS Version 2.1.

BACKGROUND: Biparametric MRI (bpMRI) without dynamic contrast-enhanced MRI (DCE-MRI) results in an elimination of adverse events, shortened examination time, and reduced costs, compared to multiparametric MRI (mpMRI). The ability of bpMRI to detect clinically significant prostate cancer (csPC) with the Prostate Imaging and Reporting Data System version 2.1 (PI-RADS v2.1) compared to standard mpMRI has not been studied extensively. PURPOSE: To compare the interobserver reliability and diagnostic performance for detecting csPC of bpMRI and mpMRI using PI-RADS v2.1. STUDY TYPE: Retrospective. POPULATION: In all, 103 patients with elevated prostate-specific antigen (PSA) levels who underwent mpMRI and subsequent MRI-ultrasonography fusion-guided prostate-targeted biopsy (MRGB) with or without prostatectomy. FIELD STRENGTH/SEQUENCES: T2 -weighted imaging (T2 WI), diffusion-weighted imaging (DWI), and DCE-MRI at 3T. ASSESSMENT: Three readers independently assessed each suspected PC lesion, assigning a score of 1-5 for T2 WI, a score of 1-5 for DWI, and positive and negative for DCE-MRI according to PI-RADS v2.1 and determined the overall PI-RADS assessment category of bpMRI (T2 WI and DWI) and mpMRI (T2 WI, DWI, and DCE-MRI). The reference standard was MRGB or prostatectomy-derived histopathology. STATISTICAL TESTING: Statistical analysis was performed using the kappa statistic and McNemar and Delong tests. RESULTS: Of the 165 suspected PC lesions in 103 patients, 81 were diagnosed with csPC and 84 with benign conditions. Interobserver variability of PI-RADS assessment category showed good agreement for bpMRI (kappa value = 0.642) and mpMRI (kappa value = 0.644). For three readers, the diagnostic sensitivity was significantly higher for mpMRI than for bpMRI (P < 0.001 to P = 0.016, respectively), whereas diagnostic specificity was significantly higher for bpMRI than for mpMRI (P < 0.001 each). For three readers, the area under the receiver operating characteristic curve (AUC) was higher for bpMRI than for mpMRI; however, the difference was significant only for Reader 1 and Reader 3 (Reader 1: 0.823 vs. 0.785, P = 0.035; Reader 2: 0.852 vs. 0.829, P = 0.099; and Reader 3: 0.828 vs. 0.773, P = 0.002). DATA CONCLUSION: For detecting csPC using PI-RADS v2.1, the interobserver reliability and diagnostic performance of bpMRI was comparable with those of mpMRI. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY STAGE: 2.

Randomized head-to-head comparison of minodronic acid and raloxifene for fracture incidence in postmenopausal Japanese women: the Japanese Osteoporosis Intervention Trial (JOINT)-04.

AIMS: We conducted a head-to-head randomized trial of minodronate, a bisphosphonate, and raloxifene, a selective estrogen receptor modulator, to obtain clinical evidence and information about their efficacy and safety. METHODS: The Japanese Osteoporosis Intervention Trial protocol number 4 (JOINT-04) trial is a multi-center, open-labeled, blinded endpoints, head-to-head randomized trial of minodronate and raloxifene. Ambulatory elderly women with osteoporosis (age, >60 years) were randomly allocated to the raloxifene or minodronate group by central registration. The co-primary endpoints included any one of osteoporotic fractures (vertebral, humeral, femoral, and radial fractures), vertebral fractures, and major osteoporotic fractures (clinical vertebral, humeral, femoral, and radial fractures). The biological effects of each drug, patients' quality of life, and drug safety were assessed based on the secondary outcomes. This study was registered at the University Hospital Medical Information Network-Clinical Trials Registry (UMIN-CTR) under trial identification number UMIN000005433. RESULTS: A total of 3896 patients were randomized to the minodronate and raloxifene groups, and drug efficacy assessments were performed for 3247 patients (1623 and 1624 patients, respectively). Among these patients, 1176 and 1187 patients received allocated treatment for 2 years. The incidence rate ratios for osteoporotic, vertebral, and major osteoporotic fractures in the minodronate group were 0.94 (95% CI: 0.78-1.13, p = .494), 0.86 (95% CI: 0.70-1.05, p = .147), and 1.22 (95% CI: 0.86-1.74, p = .274), respectively. Compared to the raloxifene group, the minodronate group showed significantly increased bone mineral density of the lumbar spine for each visit (6 months: p = .007, 12 months: p = .0003, 24 months: p<.0001). Also, serious adverse reactions were observed for four and six patients in the minodronate and raloxifene groups, respectively. CONCLUSIONS: Overall, there were no statistical differences in the incidence rates of osteoporotic, vertebral, or major osteoporotic fractures between the two groups. Serious adverse reactions were rare in both groups.

Comparison of PI-RADS version 2 and PI-RADS version 2.1 for the detection of transition zone prostate cancer.

PURPOSE: To compare the diagnostic performance of PI-RADS v2 and v2.1 for detecting transition zone prostate cancer (TZPC) on multiparametric prostate MRI (mpMRI). METHOD: Fifty-eight patients with elevated PSA levels underwent mpMRI at 3 T including T2-weighted imaging (T2WI) and diffusion-weighted imaging (DWI), and subsequent MRI-transrectal ultrasonography fusion-guided prostate-targeted biopsy (MRGB). The standard of reference was MRGB-derived histopathology. Two readers independently assessed each TZ lesion, assigning a score of 1-5 for T2WI, a score of 1-5 for DWI, and the overall PI-RADS assessment category according to PI-RADS v2 and v2.1. The diagnostic performance of the two methods was compared in terms of inter-reader agreement, diagnostic sensitivity, diagnostic specificity, and area under the ROC curve (AUC). RESULTS: Of the 58 patients, 26 were diagnosed with PC (GS = 3 + 3, n = 9; GS = 3 + 4, n = 9; GS = 3 + 5, n = 1; GS = 4 + 3, n = 4; GS = 4 + 4, n = 3) and 32 with benign lesions. Regarding inter-reader agreement of overall PI-RADS assessment category, the kappa value was 0.580 for v2 and 0.645 for v2.1. For both readers, there was no difference in diagnostic sensitivity between the versions (p ≥ 0.500). For reader 1, the diagnostic specificity was higher for v2.1 (p = 0.002), and was similar for reader 2 (p = 1.000). For both readers, AUC tended to be higher for v2.1 than for v2, but the difference was not significant (0.786 vs. 0.847 for reader 1, p = 0.052; and 0.808 vs. 0.858 for reader 2, p = 0.197). CONCLUSIONS: These results suggest that compared with PI-RADS v2, PI-RADS v2.1 could be preferable for evaluating TZ lesions.

Multidimensional analysis of clinicopathological characteristics of false-negative clinically significant prostate cancers on multiparametric MRI of the prostate in Japanese men.

PURPOSE: To clarify clinicopathological features of false-negative clinically significant prostate cancer (csPC) at multiparametric prostate MRI (mpMRI). METHODS: 95 patients with 139 csPC undergoing 3T mpMRI before radical prostatectomy were included. Two radiologists were independently evaluated mpMR images using PI-RADS v2. Clinicopathological findings were compared between (a) detectable and undetectable lesions using overall mpMRI criteria (o-mpMRI criteria) and (b) lesions with early enhancement effect (EEE) and lesions without EEE at DCE-MRI. RESULTS: The detection rate of csPS using cutoff value of category 3 or more in PI-RADS v2 for positive lesion was 72.1% (98/136 lesions). In 38 false-negative lesions with less than PI-RADS v2 category 3, the DCE-MRI detected 14 lesions. 17 undetectable lesions on o-mpMR criteria had lower PSA and D'amico risk classification, and higher tumor apparent diffusion coefficient (ADC) than those of 118 detectable lesions (p ≤ 0.048). 89 lesions with EEE showed higher PSA, tumor size, prostatectomy GS grade, frequency of lesions with GS ≥ 4 + 3 and lower tumor ADC than those in 38 lesions without EEE (p ≤ 0.046). CONCLUSION: Tumor detectability of csPC with PI-RADS v2 was limited compared with o-mpMRI criteria in Japanese men. Moreover, false-negative lesions on o-mpMRI criteria were characterized as small in size, low risk and low cellularity.

Pharmacological inhibition of tankyrase induces bone loss in mice by increasing osteoclastogenesis.

Tankyrase is a poly (ADP-ribose) polymerase that leads to ubiquitination and degradation of target proteins. Since tankyrase inhibitors suppress the degradation of AXIN protein, a negative regulator of the canonical Wnt pathway, they effectively act as Wnt inhibitors. Small molecule tankyrase inhibitors are being investigated as drug candidates for cancer and fibrotic diseases, in which the Wnt pathways are aberrantly activated. Tankyrase is also reported to degrade the adaptor protein SH3BP2 (SH3 domain-binding protein 2). We have previously shown that SH3BP2 gain-of-function mutation enhances receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis in murine bone marrow-derived macrophages (BMMs). Although the interaction between tankyrase and SH3BP2 has been reported, it is not clear whether and how the inhibition of tankyrase affects bone cells and bone mass. Here, we have demonstrated that tankyrase inhibitors (IWR-1, XAV939, and G007-LK) enhanced RANKL-induced osteoclast formation and function in murine BMMs and human peripheral blood mononuclear cells through the accumulation of SH3BP2, subsequent phosphorylation of SYK, and nuclear translocation of NFATc1. Tankyrase inhibitors also enhanced osteoblast differentiation and maturation, represented by increased expression of osteoblast-associated genes accompanied by the accumulation of SH3BP2 protein and enhanced nuclear translocation of ABL, TAZ, and Runx2 in primary osteoblasts. Most importantly, pharmacological inhibition of tankyrase in mice significantly decreased tibia and lumbar vertebrae bone volumes in association with increased numbers of osteoclasts. Our findings uncover the role of tankyrase inhibition in bone cells and highlight the potential adverse effects of the inhibitor on bone.

18F-FDG PET/CT Imaging of Epididymal Smooth Muscle Mass Mimicking Recurrent Lymphoma.

An 84-year-old man with a history of diffuse large B-cell lymphoma in remission who had completed chemotherapy 3 years previously was referred for imaging evaluation of disease recurrence. Abnormal accumulation in the left scrotum was demonstrated on F-FDG PET/CT. Subsequent ultrasonography showed a nodular mass lesion in the left epididymis. He then underwent left orchiectomy. Histopathological examination of the mass diagnosed smooth muscle hyperplasia/hamartoma of the left epididymis. Epididymal smooth muscle hyperplasia/hamartoma should be included as a differential diagnosis for malignant scrotal tumor.

Differentiation of subtypes of renal cell carcinoma: dynamic contrast-enhanced magnetic resonance imaging versus diffusion-weighted magnetic resonance imaging.

OBJECTIVE: The objective was to compare the performance of dynamic contrast-enhanced (DCE) and diffusion-weighted (DW) magnetic resonance (MR) imaging in the differentiation of subtypes of renal cell carcinoma (RCC). MATERIALS/METHODS: This study included 45 renal tumors of clear cell (n=36) and non-clear-cell (n=9) RCC. The contrast enhancement ratios (CERs) and the apparent diffusion coefficient (ADC) values on MR imaging were compared between the clear cell and non-clear-cell RCC groups. RESULTS: In the comparison of diagnostic performance between DCE and DW MR imaging, areas under the curves were 0.968 and 0.797 for the CERs of the corticomedullary and the ADC value. CONCLUSION: The CER of the corticomedullary phase was more reliable in distinguishing between clear cell and non-clear-cell RCCs.

Incremental value of high b value diffusion-weighted magnetic resonance imaging at 3-T for prediction of extracapsular extension in patients with prostate cancer: preliminary experience.

PURPOSE: To investigate whether high b value diffusion-weighted imaging (DWI) contributes to the improvement of diagnostic ability of extracapsular extension (ECE) in prostate cancer (PC). MATERIALS AND METHODS: Forty-three patients with PC underwent multiparametric MRI including DWI (b values: 0, 2000 s/mm2) at 3-T. Two radiologists assessed the presence of ECE and the diagnostic certainty degree using conventional diagnostic method by consensus. Tumor apparent diffusion coefficient (ADC, ×10-3 mm2/s) was also measured. Independent predictors of ECE were identified among PSA, tumor ADC, Gleason score, and conventional MRI. ECE in patients with low diagnostic certainty by conventional MRI was further reevaluated using ADC cutoff value, and the results were combined with those of patients with high diagnostic certainty by conventional MRI (MRI + ADC method). RESULTS: Tumor ADC was an independent predictor of ECE, and the ADC cutoff value was 0.72. The sensitivity, specificity, and accuracy of conventional MRI and MRI + ADC method in the diagnosis of ECE were 44, 92, and 72%, and 78, 96, and 88%, respectively. Among MRI findings leading to the judgement of low diagnostic certainty, broad tumor contact was most common (72% of the patients). CONCLUSIONS: The addition of ADC obtained with high b value DWI at 3-T to conventional MRI improved the diagnostic ability of ECE.

Value of preoperative 3T multiparametric MRI for surgical margin status in patients with prostate cancer.

PURPOSE: To examine the value of preoperative multiparametric magnetic resonance imaging (MRI) as a predictor of surgical margin (SM) status in patients with prostate cancer (PC). MATERIALS AND METHODS: The Institutional Review Board approved this retrospective study; the requirement for informed consent was waived. Fifty-six male patients with histologically proven PC underwent preoperative 3T multiparametric MRI including high b value (0, 2000 s/mm(2) ) diffusion-weighted imaging. In each patient, clinical data, such as biopsy Gleason score and D'Amico clinical risk score, and multiparametric MRI findings, such as tumor location, tumor size, tumor extension in the apical or proximal region, tumor apparent diffusion coefficient (ADC), and the presence or absence of MRI findings of extracapsular extension (ECE) were evaluated. Statistical evaluations included the Fisher's exact test, χ(2) test, Mann-Whitney U-test, and logistic regression analysis. RESULTS: On histopathological evaluation, 15 patients (27%) were SM-positive (SMP group), and 41 (73%) were SM-negative (SMN group). The tumor ADC was significantly lower in the SMP group than in the SMN group (P = 0.001). The frequency of tumor extension in the apex or base and suspected ECE on MRI were significantly higher in the SMP group than in the SMN group (P = 0.037 and 0.011, respectively). On multivariate analysis, tumor ADC was the only predictor of SM status in PC (P = 0.003). CONCLUSION: PC with positive SM was characterized by tumor extension in the apical and proximal regions, lower tumor ADC, and tumors with positive MRI findings of ECE, compared to tumors with negative SM. J. Magn. Reson. Imaging 2016;44:584-593.

Pancreatic adenocarcinomas without secondary signs on multiphasic multidetector CT: association with clinical and histopathologic features.

PURPOSE: To determine the clinical, histopathologic and imaging features of pancreatic adenocarcinomas without secondary signs on dynamic CT. MATERIALS AND METHODS: Seventy patients (mean age 70 years) with histologically proven pancreatic adenocarcinoma underwent preoperative contrast material-enhanced multiphasic multidetector CT before pancreatic resection. In each patient, clinical data including carbohydrate antigen 19-9, frequency of isoattenuating tumours, and presence of secondary signs and histopathologic findings such as tumour location, tumour stage, and microscopic infiltrative growth grade were evaluated. RESULTS: Ten tumours (14%) were without secondary signs, and 60 (86%) were with secondary signs. Tumours without and with secondary signs were located in the uncinate process in 5 (50%) and 3 (5%), head in 3 (30%) and 29 (48%), body in 2 (20%) and 22 (37%), and tail in 0 (0%) and 6 (10%), respectively (p = .001). The frequency of isoattenuating pancreatic adenocarcinomas without secondary signs was significantly higher than those with secondary signs (p = 0.034). The tumour stage of pancreatic adenocarcinomas without secondary signs was earlier than that in tumours with secondary signs (p = 0.041). CONCLUSIONS: Pancreatic adenocarcinomas without secondary signs is characterized by the presence of uncinate and isoattenuating tumours and earlier tumour stage compared to tumours with secondary signs. KEY POINTS: Frequency of pancreatic adenocarcinomas without secondary signs on multiphasic CT is 14 . Pancreatic adenocarcinomas without secondary signs are common in the uncinate process. Pancreatic adenocarcinomas without secondary signs are common in isoattenuating tumours. Pancreatic adenocarcinomas without secondary signs are characterized by earlier-stage tumours.

Prognosis of small hepatocellular nodules detected only at the hepatobiliary phase of Gd-EOB-DTPA-enhanced MR imaging as hypointensity in cirrhosis or chronic hepatitis.

PURPOSE: To evaluate the prognosis of "strict" high-risk nodules (small hepatocellular nodules detected only in the hepatobiliary phase of initial Gd-EOB-DTPA-enhanced MR examination) in patients with cirrhosis or chronic hepatitis. METHODS AND MATERIALS: The study included thirty-three patients with 60 "strict" high-risk nodules showing hypointensity at the hepatobiliary phase that was undetectable at the vascular phase and other conventional sequences of initial Gd-EOB-DTPA-enhanced MR imaging. These nodules were observed on follow-up MR examinations until hypervascularity was detected. The potential predictive factors for hypervascular transformation were compared between two groups (group A showing hypervascular transformation, group B not showing hypervascularization). RESULTS: Ten (16.7 %) of 60 "strict" high-risk nodules showed hypervascular transformation during follow-up periods (group A). The growth rates of the nodules in group A (6.3 ± 4.5 mm/year) were significantly higher than those in group B (3.4 ± 7.2 mm/year) (p = 0.003). Additionally, the median observation period in group A (177.5 ± 189.5 day) was significantly shorter than in group B (419 ± 372.2 day) (p = 0.045). The other predictive factors were not significantly correlated with hypervascularization. CONCLUSIONS: Subsets of "strict" high-risk nodules showed hypervascular transformation during follow-up periods in association with increased growth rates, indicating that nodule growth rate is an important predictive factor for hypervascularization. KEY POINTS: • "Strict" high-risk nodules are defined as hepatocellular nodules detected only in the hepatobiliary-phase. • Subsets of "strict" high-risk nodules showed hypervascular transformation during follow-up periods. • Increased growth rate is an important predictive factor for hypervascular transformation. • Management of patients with "strict" high-risk nodules becomes more appropriate.

High b value (2,000 s/mm2) diffusion-weighted magnetic resonance imaging in prostate cancer at 3 Tesla: comparison with 1,000 s/mm2 for tumor conspicuity and discrimination of aggressiveness.

OBJECTIVE: The objective of our study was to investigate tumor conspicuity and the discrimination potential for tumor aggressiveness on diffusion-weighted magnetic resonance imaging (DW-MRI) with high b value at 3-T. MATERIALS AND METHODS: The institutional review board approved this study and waived the requirement for informed consent. A total of 50 patients with prostate cancer (69 cancer foci; 48 in the PZ, 20 in the TZ, and one in whole prostate) who underwent multiparametric prostate MRI including DW-MRI (b values: 0, 1000 s/mm2 and 0, 2000 s/mm2) on a 3-T system were included. Lesion conspicuity score (LCS) using visual assessment (1 = invisible for surrounding normal site; 2 = slightly high intensity; 3 = moderately high; and 4 = very high) and tumor-normal signal intensity ratio (TNR) were assessed, and apparent diffusion coefficient (ADC, ×10-3 mm2/s) of the tumor regions and normal regions were measured. RESULTS: Mean LCS and TNR at 0, 2000 s/mm2 was significantly higher than those at 0, 1000 s/mm2 (p<0.001 for both). In addition, ADC at both 0, 1000 and 0, 2000 s/mm2 was found to distinguish intermediate or high risk cancer with Gleason score ≥7 from low risk cancer with Gleason score ≤6 (p<0.001 for both). Furthermore, ADC of tumor regions correlated with Gleason score at both 0, 1000 s/mm2 (ρ = -0.602; p<0.001) and 0, 2000 s/mm2 (ρ = -0.645; p<0.001). CONCLUSIONS: For tumor conspicuity and characterization of prostate cancer on DW-MRI of 3-T MRI, b = 0, 2000 s/mm2 is more useful than b = 0, 1000 s/mm2.

Diffusion-weighted MRI and its role in prostate cancer.

In the last 5 years, the multiparametric approach has been investigated as the method for the MRI of prostate cancer. In multiparametric MRI of the prostate, at least two functional MRI techniques, such as diffusion-weighted MRI (DW-MRI) and dynamic contrast-enhanced MRI, are combined with conventional MRI, such as T2 -weighted imaging. DW-MRI has the ability to qualitatively and quantitatively represent the diffusion of water molecules by the apparent diffusion coefficient, which indirectly reflects tissue cellularity. DW-MRI is characterized by a short acquisition time without the administration of contrast medium. Thus, DW-MRI has the potential to become established as a noninvasive diagnostic method for tumor detection and localization, tumor aggressiveness, local staging and local recurrence after various therapies. Accordingly, radiologists should recognize the principles of DW-MRI, the methods of image acquisition and the pitfalls of image interpretation.