Differentiating mixed epithelial and stromal tumor family from predominantly cystic renal cell carcinoma using magnetic resonance imaging-based Bosniak classification system version 2019.

PURPOSE: To differentiate mixed epithelial and stromal tumor family (MESTF) of the kidney from predominantly cystic renal cell carcinoma (RCC) using the magnetic resonance imaging (MRI)-based Bosniak classification system version 2019 (v2019). MATERIALS AND METHODS: The study included 36 consecutive patients with MESTF and 77 with predominantly cystic RCC who underwent preoperative renal MRI. One radiologist evaluated and documented the clinical and MRI characteristics (age, sex, laterality, R.E.N.A.L. Nephrometry Score [RNS], surgical approach, the signal intensity on T2-weighted imaging, restricted diffusion and enhancement features in corticomedullary phase). Blinded to clinical and pathological information, another two radiologists independently evaluated Bosniak category of all masses. Interobserver agreement based on Bosniak classification system v2019 was measured by the weighted Cohen/Conger's Kappa coefficient. Furthermore, predominantly cystic RCCs and MESTFs were divided into low (categories I, II, and IIF) and high-class (categories III, and IV) tumors. The independent sample t test (Mann-Whitney U test) or Pearson Chi-square test (Fisher's exact probability test) was utilized to compare clinical and imaging characteristics between MESTFs and predominantly cystic RCCs. The performance of the Bosniak classification system v2019 in distinguishing MESTF from predominantly cystic RCC was investigated via receiver operating characteristic curve analysis. RESULTS: MESTF and predominantly cystic RCC groups significantly differed in terms of age, lesion size, RNS, restricted diffusion, and obvious enhancement in corticomedullary phase, but not sex, laterality, surgical approach, and the signal intensity on T2WI. Interobserver agreement was substantially based on the Bosniak classification system v2019. There were 24 low-class tumors and 12 high-class tumors in the MESTF group. Meanwhile, 13 low-class tumors and 64 high-class tumors were observed in the predominantly cystic RCC group. The distribution of low- or high-class tumors significantly differed between the MESTF and predominantly cystic RCC groups. Bosniak classification system v2019 had excellent discrimination (cutoff value = category III), and an area under curve value was 0.81; accuracy, 80.5%; sensitivity, 87.0%; and specificity, 66.7%. CONCLUSION: The MRI-based Bosniak classification system v2019 can effectively distinguish MESTF from predominantly cystic RCC if category III was used as a cutoff reference.

Diagnostic Value of Clear Cell Likelihood Score v1.0 and v2.0 for Common Subtypes of Small Renal Masses: A Multicenter Comparative Study.

BACKGROUND: Clear cell likelihood score (ccLS) is reliable for diagnosing small renal masses (SRMs). However, the diagnostic value of Clear cell likelihood score version 1.0 (ccLS v1.0) and v2.0 for common subtypes of SRMs might be a potential score extension. PURPOSE: To compare the diagnostic performance and interobserver agreement of ccLS v1.0 and v2.0 for characterizing five common subtypes of SRMs. STUDY TYPE: Retrospective. POPULATION: 797 patients (563 males, 234 females; mean age, 53 ± 12 years) with 867 histologically proven renal masses. FIELD STRENGTH/SEQUENCES: 3.0 and 1.5 T/T2 weighted imaging, T1 weighted imaging, diffusion-weighted imaging, a dual-echo chemical shift (in- and opposed-phase) T1 weighted imaging, multiphase dynamic contrast-enhanced imaging. ASSESSMENT: Six abdominal radiologists were trained in the ccLS algorithm and independently scored each SRM using ccLS v1.0 and v2.0, respectively. All SRMs had definite pathological results. The pooled area under curve (AUC), accuracy, sensitivity, and specificity were calculated to evaluate the diagnostic performance of ccLS v1.0 and v2.0 for characterizing common subtypes of SRMs. The average κ values were calculated to evaluate the interobserver agreement of the two scoring versions. STATISTICAL TESTS: Random-effects logistic regression; Receiver operating characteristic analysis; DeLong test; Weighted Kappa test; Z test. The statistical significance level was P < 0.05. RESULTS: The pooled AUCs of clear cell likelihood score version 2.0 (ccLS v2.0) were statistically superior to those of ccLS v1.0 for diagnosing clear cell renal cell carcinoma (ccRCC) (0.907 vs. 0.851), papillary renal cell carcinoma (pRCC) (0.926 vs. 0.888), renal oncocytoma (RO) (0.745 vs. 0.679), and angiomyolipoma without visible fat (AMLwvf) (0.826 vs. 0.766). Interobserver agreement for SRMs between ccLS v1.0 and v2.0 is comparable and was not statistically significant (P = 0.993). CONCLUSION: The diagnostic performance of ccLS v2.0 surpasses that of ccLS v1.0 for characterizing ccRCC, pRCC, RO, and AMLwvf. Especially, the standardized algorithm has optimal performance for ccRCC and pRCC. ccLS has potential as a supportive clinical tool. EVIDENCE LEVEL: 4. TECHNICAL EFFICACY: Stage 2.

Assessment of the Added Value of Intravoxel Incoherent Motion Diffusion-Weighted MR Imaging in Identifying Non-Diabetic Renal Disease in Patients With Type 2 Diabetes Mellitus.

BACKGROUND: Identification of non-diabetic renal disease (NDRD) in patients with type 2 diabetes mellitus (T2DM) may help tailor treatment. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) is a promising tool to evaluate renal function but its potential role in the clinical differentiation between diabetic nephropathy (DN) and NDRD remains unclear. PURPOSE: To investigate the added role of IVIM-DWI in the differential diagnosis between DN and NDRD in patients with T2DM. STUDY TYPE: Prospective. POPULATION: Sixty-three patients with T2DM (ages: 22-69 years, 17 females) confirmed by renal biopsy divided into two subgroups (28 DN and 35 NDRD). FIELD STRENGTH/SEQUENCE: 3 T/ T2 weighted imaging (T2WI), and intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI). ASSESSMENT: The parameters derived from IVIM-DWI (true diffusion coefficient [D], pseudo-diffusion coefficient [D*], and pseudo-diffusion fraction [f]) were calculated for the cortex and medulla, respectively. The clinical indexes related to renal function (eg cystatin C, etc.) and diabetes (eg diabetic retinopathy [DR], fasting blood glucose, etc.) were measured and calculated within 1 week before MRI scanning. The clinical model based on clinical indexes and the IVIM-based model based on IVIM parameters and clinical indexes were established and evaluated, respectively. STATISTICAL TESTS: Student's t-test; Mann-Whitney U test; Fisher's exact test; Chi-squared test; Intraclass correlation coefficient; Receiver operating characteristic analysis; Hosmer-Lemeshow test; DeLong's test. P < 0.05 was considered statistically significant. RESULTS: The cortex D*, DR, and cystatin C values were identified as independent predictors of NDRD in multivariable analysis. The IVIM-based model, comprising DR, cystatin C, and cortex D*, significantly outperformed the clinical model containing only DR, and cystatin C (AUC = 0.934, 0.845, respectively). DATA CONCLUSION: The IVIM parameters, especially the renal cortex D* value, might serve as novel indicators in the differential diagnosis between DN and NDRD in patients with T2DM. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.

Differentiation between renal epithelioid angiomyolipoma and clear cell renal cell carcinoma using clear cell likelihood score.

PURPOSE: Clear cell likelihood score (ccLS) may be a reliable diagnostic method for distinguishing renal epithelioid angiomyolipoma (EAML) and clear cell renal cell carcinoma (ccRCC). In this study, we aim to explore the value of ccLS in differentiating EAML from ccRCC. METHODS: We performed a retrospective analysis in which 27 EAML patients and 60 ccRCC patients underwent preoperative magnetic resonance imaging (MRI) at our institution. Two radiologists trained in the ccLS algorithm scored independently and the consistency of their interpretation was evaluated. The difference of the ccLS score was compared between EAML and ccRCC in the whole study cohort and two subgroups [small renal masses (SRM; ≤ 4 cm) and large renal masses (LRM; > 4 cm)]. RESULTS: In total, 87 patients (59 men, 28 women; mean age, 55±11 years) with 90 renal masses (EAML: ccRCC = 1: 2) were identified. The interobserver agreement of two radiologists for the ccLS system to differentiate EAML from ccRCC was good (k = 0.71). The ccLS score in the EAML group and the ccRCC group ranged from 1 to 5 (73.3% in scores 1-2) and 2 to 5 (76.7% in scores 4-5), respectively, with statistically significant differences (P < 0.001). With the threshold value of 2, ccLS can distinguish EAML from ccRCC with the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 87.8%, 95.0%, 73.3%, 87.7%, and 88.0%, respectively. The AUC (area under the curve) was 0.913. And the distribution of the ccLS score between the two diseases was not affected by tumor size (P = 0.780). CONCLUSION: The ccLS can distinguish EAML from ccRCC with high accuracy and efficiency.

Comparison of Polyvinyl Alcohol Versus Combination of Lipiodol-Bleomycin Emulsion and NBCA-Lipiodol Emulsion for Renal Angiomyolipoma Embolization: A Prospective Randomized Study.

BACKGROUND. Consensus is lacking regarding optimal embolic agents for transcatheter arterial embolization (TAE) of renal angiomyolipomas (AMLs). OBJECTIVE. The purpose of our study was to compare the safety and efficacy of TAE with polyvinyl alcohol (PVA) and TAE with a combination of ethiodized oil (Lipiodol)-bleomycin emulsion and N-butyl cyanoacrylate (NBCA)-Lipiodol emulsion for the treatment of patients with large or symptomatic AMLs. METHODS. This prospective study enrolled patients referred for TAE of a large (> 4 cm) or symptomatic renal AML from July 2007 to December 2018. Patients were randomized to undergo TAE using PVA particles or a combination of Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion. Patients underwent serial clinical follow-up visits and follow-up CT or MRI examinations after TAE. Outcomes were compared between groups. RESULTS. Seventy-eight patients were enrolled. After exclusions, the analysis included 72 patients (15 men, 57 women; mean age, 35.0 years; 51 patients with hematuria, 66 patients with flank pain): 35 patients were randomized to treatment by PVA and 37 were randomized to treatment by a combination of Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion. Complete occlusion of all angiographically visible arterial supply was achieved in all patients. No major adverse event occurred in any patient. The mean follow-up after TAE was 77 ± 45 (SD) months (range, 37-180 months). The frequency of resolution of hematuria after initial TAE without recurrence was greater after treatment by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than by PVA (100.0% vs 80.0%, respectively; p = .03). At 12-month follow-up, the frequency of complete resolution of flank pain was higher after treatment by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than by PVA (100.0% vs 75.0%, p = .03). Mean reduction in AML volume at 36 months or longer after TAE versus at baseline was greater in patients treated by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than in those treated by PVA (98.0% vs 85.7%, respectively; p = .04). The frequency of complete response by modified RECIST (mRECIST) criteria at 36 months or longer after TAE was greater in patients treated by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than by PVA (94.6% vs 74.3%, p = .04). The rate of repeat TAE was higher among patients treated by PVA than among those treated by Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion (25.7% vs 8.1%, p = .04). CONCLUSION. Superior outcomes after TAE of AML were achieved using Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion than using PVA. CLINICAL IMPACT. TAE using a combination of Lipiodol-bleomycin emulsion and NBCA-Lipiodol emulsion is a safe and effective treatment option for large or symptomatic AMLs. TRIAL REGISTRATION. Chinese Clinical Trial Registry ChiCTR2100053296.

Prostate arterial chemoembolization for treatment of refractory hematuria and urinary retention in patients with localized advanced prostate cancer.

OBJECTIVES: To evaluate the safety and efficacy transcatheter arterial chemoembolization (TACE) for the treatment of refractory gross hematuria (RGH) and urinary retention (UR) secondary to localized advanced prostate cancer (PCa). PATIENTS AND METHODS: Thirty-two patients (mean age 72.5 years, range 60-89) with advanced PCa-related RGH that failed conventional therapy were included. Twenty-two of these patients had catheter-dependent due to PCa-related UR. TACE was performed with epirubicin (EPI)-eluting HepaSpheres (HS) plus intra-arterial (IA) infusion of docetaxel. Technical success, adverse events (AEs), overall survival (OS), control of RGH, removal of indwelling catheters, and local disease control, were evaluated. RESULTS: Technical success was achieved in 100% without major AEs. Mean follow up post-TACE was 27 months (range 8-56 months) with a mean OS of 30 months. GRH stopped within 5 days after TACE in all patients, 26 (86.7%) of these patients exhibited good bleeding control during a mean follow-up of 24 months; 17 (77.3%) of the 22 patients with UR had recovered spontaneous urination, 15 (88.2%) patients were catheter-free at their last follow-up with a mean of 24 months. BS was obtained in 73.3% (22/30) of patients at a mean follow-up of 29 months. At the last visit, 22 patients had a mean of 36 months follow-up and the mean percentage reduction in prostate volume was 55.5%, with a statistically different from baseline (P = 0.022). Negative biopsy results were obtained in 84.2% (16/19) of the patients at 12-47 months after TACE. Compared with baseline values, there was a significant improvements in IPSS, QoL, Qmax, and PVR (all P < 0.05). CONCLUSIONS: TACE using EPI-eluting HS plus IA infusion of docetaxel is a safe and effective treatment option for the advanced PCa patients with GRH and UR, and it could be considered as an alternative if there was no other therapeutic choice.

Long-term outcomes of transarterial embolization with lipiodol-bleomycin emulsion plus polyvinyl alcohol particles versus the particles alone for large symptomatic focal nodular hyperplasia: a propensity score-matched analysis.

OBJECTIVES: To compare the efficacy of transarterial embolization (TAE) with polyvinyl alcohol (PVA) particles alone and lipiodol-bleomycin emulsion (LBE) plus PVA particles for patients with unresectable large symptomatic focal nodular hyperplasia (FNH). METHODS: We performed a retrospective analysis of patients who underwent TAE either with PVA particles alone (group A, n = 46) or LBE plus PVA particles (group B, n = 35) for large (≥ 7 cm) symptomatic FNH between January 2002 and February 2019. Propensity score matching (PSM) (1:1) was performed to adjust for potential baseline confounders. Technical success, adverse events (AEs), symptom relief, and changes in the lesion size after TAE were evaluated. Statistical analysis included Wilcoxon rank sum test and χ2 test. RESULTS: After PSM, no significant differences in baseline characteristics were found between the groups (31 in group A and 31 in group B, with a mean age of 31 years). Technical success was achieved in all patients (100%), without major AEs in both groups. Complete resolution of the abdominal symptoms was reported in 77.4% in group A and 100% in group B (p = 0.037) during a mean follow-up period of 72 months; complete resolution (CR) of the FNH rate was significantly higher in group B than in group A (93.6% vs. 67.7%; p = 0.019). CONCLUSION: Compared with the use PVA particles alone, TAE with LBE plus PVA particles in the treatment of patients with large symptomatic FNH had a significantly higher rates of CR of the FNH and complete relief of the symptoms. KEY POINTS: • Transarterial embolization (TAE) with lipiodol-bleomycin emulsion (LBE) plus PVA particles for the large symptomatic FNH yielded better results than with PVA particles alone, in terms of complete resolution of FNH lesions (93.6% vs 67.7%) and complete relief of the abdominal symptoms (100% vs 77.4%) during a mean follow-up period of 72 months (38-170 months). • No major complications were recorded in both groups, and no significant difference in the incidence of postembolization syndrome were observed between the two groups.

MRI-based Bosniak Classification of Cystic Renal Masses, Version 2019: Interobserver Agreement, Impact of Readers' Experience, and Diagnostic Performance.

Background The 2019 Bosniak classification (version 2019) of cystic renal masses (CRMs) provides a systematic update to the currently used 2005 Bosniak classification (version 2005). Further validation is required before widespread application. Purpose To evaluate the interobserver agreement of MRI criteria, the impact of readers' experience, and the diagnostic performance between version 2019 and version 2005. Materials and Methods From January 2009 to December 2018, consecutive patients with CRM who had undergone renal MRI and surgical-pathologic examination were included in this retrospective study. On the basis of version 2019 and version 2005, all CRMs were independently classified by eight radiologists with different levels of experience. By using multirater κ statistics, interobserver agreement was evaluated with comparisons between classifications and between senior and junior radiologists. Diagnostic performance between classifications by dichotomizing classes I-IV into lower (I-IIF) and higher (III-IV) classes was compared by using the McNemar test. P < .05 was considered to indicate a statistically significant difference. Results A total of 207 patients (mean age ± standard deviation, 49 years ± 12; 139 male and 68 female patients) with CRMs were included. Overall, interobserver agreement was higher with version 2019 than version 2005 (weighted κ = 0.64 vs 0.50, respectively; P < .001). Interobserver agreement between senior and junior radiologists did not differ between version 2019 (weighted κ = 0.65 vs 0.64, respectively; P = .71) and version 2005 (weighted κ = 0.54 vs 0.46; P < .001). Diagnostic specificity for malignancy was higher with version 2019 than with version 2005 (83% [92 of 111] vs 68% [75 of 111], respectively; P < .001), without any difference in sensitivity (89% [85 of 96] vs 84% [81 of 96]; P = .34). Conclusion In the updated Bosniak classification, interobserver agreement improved and was unaffected by observers' experience. The diagnostic performance with version 2019 was superior to that with version 2005, with higher specificity. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Choyke in this issue.

Multiparametric MRI Radiomic Model for Preoperative Predicting WHO/ISUP Nuclear Grade of Clear Cell Renal Cell Carcinoma.

BACKGROUND: Nuclear grade is of importance for treatment selection and prognosis in patients with clear cell renal cell carcinoma (ccRCC). PURPOSE: To develop and validate an MRI-based radiomic model for preoperative predicting WHO/ISUP nuclear grade in ccRCC. STUDY TYPE: Retrospective. POPULATION: In all, 379 patients with histologically confirmed ccRCC. Training cohort (n = 252) and validation cohort (n = 127) were randomly assigned. FIELD STRENGTH/SEQUENCE: Pretreatment 3.0T renal MRI. Imaging sequences were fat-suppressed T2 WI, contrast-enhanced T1 WI, and diffusion weighted imaging. ASSESSMENT: Three prediction models were developed using selected radiomic features, radiomic and clinicoradiologic characteristics, and a model containing only clinicoradiologic characteristics. Receiver operating characteristic (ROC) curves and area under the curve (AUC) were used to assess the predictive performance of these models in predicting high-grade ccRCC. STATISTICAL TESTS: The least absolute shrinkage and selection operator (LASSO) and minimum redundancy maximum relevance (mRMR) method were used for the selection of radiomic features and clinicoradiologic characteristics, respectively. Multivariable logistic regression analysis was used to develop the radiomic signature of radiomic features and clinicoradiologic model of clinicoradiologic characteristics. RESULTS: The radiomic signature showed good performance in discriminating high-grade (grades 3 and 4) from low-grade (grades 1 and 2) ccRCC, with sensitivity, specificity, and AUC of 77.3%, 80.0%, and 0.842, respectively, in the validation cohort. The radiomic model, combining radiomic signature and clinicoradiologic characteristics, displayed good predictive ability for high-grade with sensitivity, specificity, and accuracy of 63.6%, 93.3%, and 88.2%, respectively, in the validation cohort. The radiomic model showed a significantly better performance than the clinicoradiologic model (P < 0.05). DATA CONCLUSION: Multiparametric MRI-based radiomic model can predict WHO/ISUP grade in patients with ccRCC with satisfying performance, and thus could help the physician to improve treatment decisions. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2.

Value of Texture Analysis of Intravoxel Incoherent Motion Parameters in Differential Diagnosis of Pancreatic Neuroendocrine Tumor and Pancreatic Adenocarcinoma.

Objective To evaluate the value of texture features derived from intravoxel incoherent motion (IVIM) parameters for differentiating pancreatic neuroendocrine tumor (pNET) from pancreatic adenocarcinoma (PAC).Methods Eighteen patients with pNET and 32 patients with PAC were retrospectively enrolled in this study. All patients underwent diffusion-weighted imaging with 10 b values used (from 0 to 800 s/mm 2). Based on IVIM model, perfusion-related parameters including perfusion fraction (f), fast component of diffusion (Dfast) and true diffusion parameter slow component of diffusion (Dslow) were calculated on a voxel-by-voxel basis and reorganized into gray-encoded parametric maps. The mean value of each IVIM parameter and texture features [Angular Second Moment (ASM), Inverse Difference Moment (IDM), Correlation, Contrast and Entropy] values of IVIM parameters were measured. Independent sample t-test or Mann-Whitney U test were performed for the between-group comparison of quantitative data. Regression model was established by using binary logistic regression analysis, and receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic efficiency.Results The mean f value of the pNET group were significantly higher than that of the PAC group (27.0% vs. 19.0%, P = 0.001), while the mean values of Dfast and Dslow showed no significant differences between the two groups. All texture features (ASM, IDM, Correlation, Contrast and Entropy) of each IVIM parameter showed significant differences between the pNET and PAC groups (P=0.000-0.043). Binary logistic regression analysis showed that texture ASM of Dfast and texture Correlation of Dslow were considered as the specific imaging variables for the differential diagnosis of pNET and PAC. ROC analysis revealed that multiple texture features presented better diagnostic performance than IVIM parameters (AUC 0.849-0.899 vs. 0.526-0.776), and texture ASM of Dfast combined with Correlation of Dslow in the model of logistic regression had largest area under ROC curve for distinguishing pNET from PAC (AUC 0.934, cutoff 0.378, sensitivity 0.889, specificity 0.854).Conclusions Texture analysis of IVIM parameters could be an effective and noninvasive tool to differentiate pNET from PAC.

Effectiveness of Contrast-enhanced MR Angiography for Visualization of the Prostatic Artery prior to Prostatic Arterial Embolization.

Background A major technical challenge of prostatic arterial embolization (PAE) is the identification and catheterization of the prostatic arteries (PAs). Recently, MR angiography has been shown to help visualize PAs, but the clinical utility of MR angiography for this purpose is not known. Purpose To determine the efficacy of contrast material-enhanced MR angiography in identifying the PA and to evaluate its role in PAE for benign prostatic hyperplasia (BPH). Materials and Methods In this prospective study, 100 consecutive men who were scheduled to undergo PAE for BPH from January 2015 to May 2017 were assigned by using a randomized block design to either group A (n = 50; mean age, 71.7 years ± 11.9 [standard deviation]) without MR angiography or group B (n = 50; mean age, 72.3 years ± 12.2) with MR angiography prior to PAE. MR angiography findings of the PA anatomy were compared with those of digital subtraction angiography (DSA). The Student t test and Wilcoxon rank-sum test were used to compare the differences between the parameters indicating the performance of PAE. Results The mean age of the 100 men in the study was 72.0 years ± 11.8 (range, 51-88 years). Compared with DSA as the reference standard, MR angiography identified PAs with a sensitivity of 91.5% (97 of 106) and a positive predictive value of 100% (97 of 97). With the knowledge of tube obliquity and anatomy, group B had lower procedure times than group A (82.3 minutes ± 5.4 vs 123.9 minutes ± 12.4, P < .001) and shorter fluoroscopy times (13.8 minutes ± 2.7 vs 28.5 minutes ± 8.0, P < .001). Additionally, radiation dose was reduced for group A versus group B, from a median of 920 to 339 mGy (P = .004). Conclusion Contrast-enhanced MR angiography can accurately show anatomy for the prostate arteries, leading to shorter prostatic artery embolization times and lower radiation dose than when preprocedural prostate MR angiography is not performed. Published under a CC BY 4.0 license. Online supplemental material is available for this article. See also the editorial by Prince in this issue.

Differentiation between pancreatic metastases from clear cell renal cell carcinoma and pancreatic neuroendocrine tumor using double-echo chemical shift imaging.

PURPOSE: The purpose of the study was to retrospectively analyze whether double-echo gradient-echo (GRE) chemical shift imaging (CSI) can differentiate between pancreatic metastases from clear cell renal cell carcinoma (PM-ccRCC) and pancreatic neuroendocrine tumor (pNET). METHODS: Institutional review board approval and informed consent were waived. CSI, T2WI, DWI, and DCE magnetic resonance imaging (MRI) were performed in patients with PM-ccRCC and pNET. Eleven patients with PM-ccRCC and 24 patients with pNET were enrolled into this retrospective study. The signal intensity was measured in the pancreatic tumor and spleen on in-phase and opposed-phase images. The signal intensity index (SII) and tumor-to-spleen ratio (TSR) in PM-ccRCC and pNET were calculated and compared. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic accuracy of SII and TSR in the differentiation between PM-ccRCC and pNET. RESULTS: The SII between PM-ccRCC and pNET (20.3% ± 16.8% vs. - 3.2% ± 11.4%) was significantly different (P < 0.001), as was the TSR (- 19.2% ± 16.6% vs. 6.0% ± 13.8%) (P < 0.001). The area under the ROC curve was 0.917 for the SII and 0.902 for the TSR. Additionally, an SII threshold value of 8.1% permitted the differentiation of PM-ccRCC from pNET with a sensitivity of 90.9%, a specificity of 91.7%, a positive predictive value of 90.1%, a negative predictive value of 91.7%, and an accuracy of 91.4%. A TSR cut-off value of - 4.7% enabled the differentiation of the two groups with a sensitivity of 79.2%, a specificity of 90.9%, a positive predictive value of 90.9%, a negative predictive value of 79.2% and an accuracy of 82.9%. CONCLUSION: Double-echo GRE chemical shift MR imaging can accurately differentiate between PM-ccRCC and pNET.

Clinical and Magnetic Resonance Imaging Features of Solid Pseudopapillary Tumor of the Pancreas in Male Patients.

Objective To analyze the clinical and magnetic resonance imaging(MRI)findings of solid pseudopapillary tumor(SPT)of the pancreas in male patients. Methods Clinical and MRI features of 51 patients with pathologically-proved SPT were retrospectively analyzed.The following MRI features of the lesions were analyzed:location,maximal diameter,shape,margin,capsule,solid and cystic components,signal intensity characteristics,and enhancement patterns.Results The average maximal diameter of the SPT in male patients was significantly smaller [(3.9±1.6)cm vs.(6.3±3.9)cm,P=0.035]than that of SPT in female patients.Pure solid tumors were signiciantly more common in male patients(8/14)than in female patients(9/37)(P=0.037).T1-weighted images of SPT showed mainly homogenous hypo-intensity in male patients(11/14)and heterogeneous hypo-intensity in female patients(23/37)(P=0.001).Hemorrhage was more prevalent in female patients(22/37)than in male patients(2/14)(P=0.005).There were no significant differences between male and female patients regarding clinical features and other magnetic resonance features(P>0.05).Conclusions On MRI,SPT in male patients is small and shows mainly pure solid component with rare hemorrhage.The clinical and other MRI features of SPT are not different between males and females.

Dynamic Contrast-enhanced MRI in Renal Tumors: Common Subtype Differentiation using Pharmacokinetics.

Preoperative renal tumor subtype differentiation is important for radiology and urology in clinical practice. Pharmacokinetic data (K trans & V e, etc.) derived from dynamic contrast-enhanced MRI (DCE-MRI) have been used to investigate tumor vessel permeability. In this prospective study on DCE-MRI pharmacokinetic studies, we enrolled patients with five common renal tumor subtypes: clear cell renal cell carcinoma (ccRCC; n = 65), papillary renal cell carcinoma (pRCC; n = 12), chromophobic renal cell carcinoma (cRCC; n = 9), uroepithelial carcinoma (UEC; n = 14), and fat-poor angiomyolipoma (fpAML; n = 10). The results show that K trans of ccRCC, pRCC, cRCC, UEC and fpAML (0.459 ± 0.190 min-1, 0.206 ± 0.127 min-1, 0.311 ± 0.111 min-1, 0.235 ± 0.116 min-1, 0.511 ± 0.159 min-1, respectively) were different, but V e was not. K trans could distinguish ccRCC from non-ccRCC (pRCC & cRCC) with a sensitivity of 76.9% and a specificity of 71.4%, respectively, as well as to differentiate fpAML from non-ccRCC with a sensitivity of 100% and a specificity of 76.2%, respectively. Our findings suggest that DCE-MRI pharmacokinetics are promising for differential diagnosis of renal tumors, especially for RCC subtype characterization and differentiation between fpAML and non-ccRCC, which may facilitate the treatment of renal tumors.

Dynamic Contrast-enhanced MR Imaging in Renal Cell Carcinoma: Reproducibility of Histogram Analysis on Pharmacokinetic Parameters.

Pharmacokinetic parameters derived from dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) have been increasingly used to evaluate the permeability of tumor vessel. Histogram metrics are a recognized promising method of quantitative MR imaging that has been recently introduced in analysis of DCE-MRI pharmacokinetic parameters in oncology due to tumor heterogeneity. In this study, 21 patients with renal cell carcinoma (RCC) underwent paired DCE-MRI studies on a 3.0 T MR system. Extended Tofts model and population-based arterial input function were used to calculate kinetic parameters of RCC tumors. Mean value and histogram metrics (Mode, Skewness and Kurtosis) of each pharmacokinetic parameter were generated automatically using ImageJ software. Intra- and inter-observer reproducibility and scan-rescan reproducibility were evaluated using intra-class correlation coefficients (ICCs) and coefficient of variation (CoV). Our results demonstrated that the histogram method (Mode, Skewness and Kurtosis) was not superior to the conventional Mean value method in reproducibility evaluation on DCE-MRI pharmacokinetic parameters (K( trans) &Ve) in renal cell carcinoma, especially for Skewness and Kurtosis which showed lower intra-, inter-observer and scan-rescan reproducibility than Mean value. Our findings suggest that additional studies are necessary before wide incorporation of histogram metrics in quantitative analysis of DCE-MRI pharmacokinetic parameters.

Diffusion-Weighted Imaging with Two Different b-Values in Detection of Solid Focal Liver Lesions.

One hundred and eighty-two consecutive patients with suspected liver disease were recruited to receive diffusion-weighted imaging (DWI) with two different b-values, in comparison with T2-weighted imaging (T2WI). The detection rate of three MR sequences in solid focal liver lesions (FLLs) and subgroup analyses were performed. Our prospective study found that DWI600 was equivalent to DWI100 and T2WI for the detection of solid FLLs overall but was significantly more accurate in the detection of malignant solid FLLs and lesions larger than 10 mm.

Coronal diffusion-weighted magnetic resonance imaging of the kidney: agreement with axial diffusion-weighted magnetic imaging in terms of apparent diffusion coefficient values.

BACKGROUND: Coronal diffusion-weighted magnetic resonance imaging (DW-MRI) and apparent diffusion coefficient (ADC) values have gradually become applied (following conventional axial DW-MRI) in the renal analysis. To explore whether data obtained using coronal DW-MRI are comparable with those derived using axial DW-MRI, this preliminary study sought to assess the agreement in renal ADC values between coronal DW-MRI and axial DW-MRI. METHODS: Thirty-four healthy volunteers were enrolled in the study; written consents were obtained. All subjects underwent respiratory-triggered axial and coronal DW-MRI using a 1.5-MR system with b values of 0 and 800 s/mm 2 . The signal-to-noise ratios (SNRs) of the two DW-MRI sequences were measured and statistically compared using the paired t-test. The extent of agreement of ADC values of the upper pole, mid-pole, and lower pole of the kidney; the mean ADC values of the left kidney and right kidney; and the mean ADC values of the bilateral kidneys were evaluated via calculation of intraclass correlation coefficients (ICCs) or Bland-Altman method between the two DW-MRI sequences. RESULTS: The SNR of coronal DW-MR images was statistically inferior to that of axial DW-MR images (P < 0.001). The ICCs of the ADC values of each region of interest, and the mean ADC values of bilateral kidneys, between the two sequences, were greater than 0.5, and the mean ADCs of the bilateral kidneys demonstrated the highest ICC (0.869; 95% confidence interval: 0.739-0.935). In addition, 94.1% (32/34), 94.1% (32/34), and 97.1% (31/34) of the ADC bias was inside the limits of agreement in terms of the mean ADC values of the left kidneys, right kidneys, and bilateral kidneys when coronal and axial DWI-MRI were compared. CONCLUSIONS: ADC values derived using coronal DW-MRI exhibited moderate-to-good agreement to those of axial DW-MRI, rendering the former an additional useful DW-MRI method, and causing the ADC values derived using the two types of DW-MRI to be comparable.

Gd-EOB-DTPA-enhanced magnetic resonance imaging for focal liver lesions in Chinese patients: a multicenter, open-label, phase III study.

BACKGROUND: Contrast agents help to improve visibility in magnetic resonance (MR) imaging. However, owing to the large interstitial spaces of the liver, there is a reduction in the natural contrast gradient between lesions and healthy tissue. This study was undertaken to evaluate the efficacy and safety of the liver-specific MR imaging contrast agent gadoxetate disodium (Gd-EOB-DTPA) in Chinese patients. METHODS: This was a single-arm, open-label, multicenter study in patients with known or suspected focal liver lesions referred for contrast-enhanced MR imaging. MR imaging was performed in 234 patients before and after a single intravenous bolus of Gd-EOB-DTPA (0.025 mmol/kg body weight). Images were evaluated by clinical study investigators and three independent, blinded radiologists. The primary efficacy endpoint was sensitivity in lesion detection. RESULTS: Gd-EOB-DTPA improved sensitivity in lesion detection by 9.46% compared with pre-contrast imaging for the average of the three blinded readers (94.78% vs 85.32% for Gd-EOB-DTPA vs pre-contrast, respectively). Improvements in detection were more pronounced in lesions less than 1 cm. Gd-EOB-DTPA improved diagnostic accuracy in lesion classification. CONCLUSIONS: This open-label study demonstrated that Gd-EOB-DTPA improves diagnostic sensitivity in liver lesions, particularly in those smaller than 1 cm. Gd-EOB-DTPA also significantly improves the diagnostic accuracy in lesion classification, and furthermore, Gd-EOB-DTPA is safe in Chinese patients with liver lesions.

[MR appearance of multifocal clear cell renal cell carcinoma].

OBJECTIVE: To document the magnetic resonance (MR) imaging features of multifocal clear cell renal cell carcinoma (RCC). METHODS: The MR findings of 11 cases of pathologically-proved multifocal clear cell RCCs were reviewed retrospectively from January 2008 to December 2010. All patients underwent MR in a 1.5 T or a 3.0 T scanner. The MR features of the lesions were analyzed, with emphasis on the location, the signal intensity on T2-weighted imaging (T2WI), in regards to pseudocapsule, lipid component, hemorrhage, cystic degeneration, and enhancement pattern. Meanwhile, from these six aspects, the MR appearance of renal cell carcinomas occurring in the same patient were compared. RESULTS: 24 tumors (mean diameter, 3.1 cm) in the 11 patients (6 men, 5 women; age range, 36-69 years; mean age, 50.6 years) were detected. Multiple lesions in bilateral kidneys were found in 9 patients (9/11), while in unilateral kidney 2 patients (2/11). Hyperintensity on T2WI were observed in 16 lesions (16/24), while hypointensity 8 lesions (8/24); pseudocapsule was seen in all lesions; hemorrhage in 4 lesions (4/24), lipid component in 12 lesions (12/24) and cystic degeneration in 18 lesions (18/24), persistent enhancement in 22 lesions (22/24) and rapid wash-out pattern in 2 lesions (2/24). All lesions showed moderate or intense enhancement. The MR appearances of lesions in the same patient were identical in 5 cases (5/11), different in 6 cases (6/11). CONCLUSION: Multifocal clear cell RCCs occur more commonly in bilateral kidneys simultaneously than in unilateral kidney. The lesions in the same patient can show different MR imaging features, which probably facilitate the preoperative determination.

[Magnetic resonance imaging findings of Chromophobe renal cell carcinoma].

OBJECTIVE: To document the MRI features of Chromophobe cell carcinoma and to explore whether MR features vary with the tumor size. METHODS: MRI features of 34 patients (16 male, 18 female, age range from 24 - 61, average age is 49 years old), totally 35 focuses with histologically proved chromophobe cell carcinoma were studied retrospectively. All the patients underwent MR plain and dynamic contrast-enhanced scan before their surgery. Variation of signal intensity (3D LAVA) and ADC values of the lesions, and the analysis of images of T1WI, T2WI and chemical shift were all evaluated on the GE Advantage 4.4 work station. All lesions were categorized into 2 groups (tumor diameter ≤ 4 cm, or > 4 cm). The difference of imaging characteristics between these two groups was analyzed using Fisher exact test. Signal intensity variation and ADC values were analyzed by using one-way ANOVA method. RESULTS: None of the 35 cases contained fat or lipid. On T2WI 27 cases showed slightly low signal intensity (77.1%). In all cases, 4 appeared local cystic change (11.4%); 4 spotty hemorrhage (11.4%); 5 necrosis (covering less than 20% of whole tumor) (14.2%); 30 clear pseudo capsule (85.7%); 29 round-like lesions (the difference among the length, width and height was within 0.5 cm) (82.8%); and no cases showed signs of invasiveness or metastasis. The average changes of signal intensity of all the 35 cases were 119.8% on cortex period, 176.4% on medulla period and 154.5% on delayed phase. The mean ADC value of tumor was 1.08 ± 0.28×10(-3)mm(2)/s. 35 lesions were divided into two groups , 21 in group 1(diameter ≤ 4 cm) and 14 in group 2 (diameter > 4 cm). Cystic degeneration was seen in 0/21 in group 1 versus 4/14 in group 2 respectively, and hemorrhage 0/21 versus 4/14, necrosis 0/21 versus 5/14 , central scar 2/21 versus 8/14. The difference of these findings between two groups demonstrated statistical significance (P < 0.05). Variation of signal intensity and ADC values in two groups has no statistical significance. CONCLUSION: The MR features of Chromophobe renal cell carcinoma were hypointensity on T2WI, clear pseudocapsule, However, cystic degeneration, hemorrhage, necrosis and central scar are more common in larger tumors.