Computer tomography-based shape of tumor contour and texture of tumor heterogeneity are independent prognostic indicators for clinical T1b-T2 renal cell carcinoma.

PURPOSE: To evaluate association between computer tomography (CT)-based features of renal cell carcinoma (RCC) and survival outcomes. METHODS: Data of 958 patients with clinical T1b-T2 RCC who underwent partial/radical nephrectomy from June 2003 to March 2022 were retrospectively evaluated. CT images of patients were reviewed by two radiologists for texture analysis of tumor heterogeneity and shape analysis of tumor contour. Patients were divided into three groups according to patterns of CT-based features: (1) favorable feature group (n = 117); (2) intermediate feature group (n = 606); and (3) unfavorable feature group (n = 235). Kaplan-Meier survival analysis and multivariate Cox regression analysis were performed to evaluate overall survival (OS), cancer-specific survival (CSS), and recurrence-free survival (RFS). RESULTS: RCCs with unfavorable CT-based feature showed larger size on CT, higher nuclear grade, higher rate of histologic necrosis, and higher rate of capsular invasion than those in the other two groups (all p < 0.001). Unfavorable feature was associated with poorer OS (p = 0.001), CSS (p < 0.001), and RFS (p < 0.001) on Kaplan-Meier analysis. In multivariate analysis, intermediate and unfavorable features were independent predictors for recurrence (hazard ratio [HR] 2.51, 95% confidence interval [CI] 1.09-5.79, p = 0.031 and HR 3.71, 95% CI 1.58-8.73, p = 0.003, respectively), but not for overall death or RCC-specific death. CONCLUSIONS: A combination of irregular tumor contour feature with heterogeneous tumor texture feature on CT is associated with poor RFS in clinical T1b-T2 RCC preoperatively.

Clinical value of prostate health index as an indicator for recommending magnetic resonance imaging in patients with gray-zone prostate-specific antigen level.

PURPOSE: To evaluate the usefulness of prostate health index (PHI) as an indicator for recommending magnetic resonance imaging (MRI) in patients with prostate-specific antigen (PSA) gray zone level < 10 ng/mL. METHODS: 443 patients who underwent prostate biopsy (PB) after serum PHI test and MRI between April 2019 and December 2022 were enrolled. For patients with visible lesion on MRI with Prostate Imaging Reporting and Data System Score (PI-RADS) ≥ 3, MRI-targeted PB was performed in addition to systematic 12-core PB. RESULTS: The optimal cutoff value of PHI for predicting PI-RADS ≥ 3 lesions was 39.6, which was significantly associated with overall prostate cancer (OR 3.07, p = 0.018) and clinically significant prostate cancer (csPCa) (OR 4.15, p = 0.006) at MRI-targeted PB cores. When MRI was restricted to patients with PHI ≥ 39.6 alone, 28.7% of unnecessary MRI could be saved at the cost of missing 13.6% of csPCa. When omitting MRI for patients with PHI < 39.6 and PSAD < 0.12 ng/mL2, unnecessary MRI could be reduced by 20.1% with the risk of missing 6.2% of csPCa. With addition of systematic PB, 21.0% of patients with negative MRI-targeted PB were diagnosed as csPCa. CONCLUSIONS: For patients in PSA gray zone, PHI of 39.6 might be an indicator for MRI and further MRI-targeted PB in additional to PSAD of 0.12 ng/mL2, reducing 20.1% of unnecessary MRI with the minimal risk of missing 6.2% of csPCa. To maximize csPCa detection, combining both MRI-targeted and systematic PB should be also considered.

Tumor contact length with bladder wall provides effective risk stratification for lesions with a VIRADS score of 2-3.

OBJECTIVES: To evaluate the diagnostic performance of the tumor contact length (TCL) in the prediction of MIBC (muscle-invasive bladder cancer) in lesions corresponding to the vesical imaging-reporting and data system (VIRADS) score 2-3. METHODS: This is a single institution, retrospective study targeting 191 consecutive patients assigned of VIRADS score 2-3, who had pre-transurethral resection MRI from July 2019 to September 2021. Logistic regression analyses were performed to determine meaningful predictors of MIBC for this score group, and a nomogram was plotted with those variables. The diagnostic performance of each predictor was compared at predefined thresholds (VIRADS score 3 and TCL 3 cm) using the generalized linear model and ROC analysis. RESULTS: Both VIRADS score and TCL remained independent predictors of MIBC for this score group (odds ratio 7.3 for VIRADS score, and 1.3 for TCL, p < 0.01 for both). The contribution of TCL to the probability of MIBC in the nomogram was greater than that of the VIRADS score. VIRADS score had a sensitivity of 0.54 (14/26), specificity of 0.92 (203/221), and diagnostic accuracy of 0.88 (217/247), and TCL showed a sensitivity of 0.89 (23/26), specificity of 0.95 (209/221), and diagnostic accuracy of 0.94 (232/247). The difference in sensitivity (p = 0.03) and accuracy (p = 0.04) was statistically significant. The AUC was also significantly wider for TCL than for VIRADS (0.97 vs. 0.73, p < 0.01). CONCLUSION: A simple index, TCL, may be helpful in further risk stratification for MIBC in patients with a score of VIRADS 2-3. CLINICAL RELEVANCE STATEMENT: For bladder cancer patients with insufficient qualitative evidence of muscle layer invasion using VIRADS categorization, TCL, a simple quantitative indicator defined as the curvilinear contact length between the bladder wall and the tumor, may be helpful in risk stratification. KEY POINTS: • Even when only lesions with score 2-3 were targeted, VIRADS was still a meaningful indicator of MIBC. • With a predefined threshold of 3 cm applied, TCL outperformed VIRADS in the score 2-3 group, in predicting MIBC. • A longer TCL for a lesion with a VIRADS score 2 may warrant an additional warning for MIBC, whereas a shorter TCL for a lesion with a score 3 may indicate a lower risk of MIBC.

Adrenal Nodules Detected at Staging CT in Patients with Resectable Gastric Cancers Have a Low Incidence of Malignancy.

Background Guidelines recommending additional imaging for adrenal nodules lack relevant epidemiologic evidence. Purpose To measure the prevalence of adrenal nodules detected at staging CT in patients with potentially resectable gastric cancer and the proportion of patients with malignant nodules among them. Materials and Methods This retrospective study included 10 250 consecutive patients (median age, 63 years; interquartile range, 53-71 years; 6884 men) who underwent staging CT and had potentially resectable gastric cancer in a tertiary center (May 2003 to December 2018). All 10 250 CT studies were retrospectively reviewed, and patients with adrenal nodules (or thickening ≥10 mm) were identified to measure the prevalence of adrenal nodules. Among patients with adrenal nodules, the per-patient proportions of malignant nodules, adrenal metastasis from gastric cancer, and additional adrenal examinations were measured. A secondary analysis was performed by using data from the original CT reports. The same metrics that were used in the retrospective review were assessed. Results The prevalence of adrenal nodules was 4.5% (95% CI: 4.1, 4.9; 462 of 10 250). The proportions of malignant nodules and adrenal metastasis from gastric cancer were 0.4% ( 95% CI: 0.1, 1.6; two of 462) and 0% (95% CI: 0.0, 0.8; 0 of 462), respectively. A total of 27% of the patients (95% CI: 23, 31; 123 of 462) underwent additional adrenal examination. According to original CT reports, the prevalence of adrenal nodules and the proportions of malignant nodules, adrenal metastases from gastric cancer, and additional adrenal examination were 2.7% (95% CI: 2.4, 3.0; 272 of 10 250), 0.7% (95% CI: 0.1, 2.6; two of 272), 0% (95% CI: 0.0, 1.4; 0 of 272), and 42.6% (95% CI: 36.7, 48.8; 116 of 272), respectively. Conclusion Although adrenal nodules were detected frequently on staging CT images of patients with otherwise resectable gastric cancer, these nodules were rarely malignant. ©RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Baumgarten in this issue.

Who can safely evade a magnetic resonance imaging fusion-targeted biopsy (MRIFTB) for prostate imaging reporting and data system (PI-RADS) 3 lesion?

OBJECTIVE: To identify patients who can safely evade the magnetic resonance imaging fusion-targeted biopsy (MRIFTB) for prostate imaging reporting and data system (PI-RADS) 3 lesion. MATERIALS AND METHODS: Overall, 755 men with PI-RADS 3-5 lesions who underwent MRIFTB were retrospectively analyzed. Univariate and multivariate analyses were performed to determine significant predictors for clinically significant prostate cancer (CSPCa), defined as Gleason grade group ≥ II. Detection rates and negative predictive values of CSPCa were estimated according to various clinical settings. RESULTS: Median age, prostate-specific antigen (PSA), and PSA density of patients were 66.0 years, 7.39 ng/mL, and 0.19 ng/mL, respectively. Overall detection rates of CSPCa according to PI-RADS 3 (n = 347), 4 (n = 260), and 5 (n = 148) lesions were 15.0%, 30.4%, and 80.4%, respectively. The negative predictive value (NPV) of PI-RADS 3 lesion on MRI was 15.0%. On multivariate analysis, age [≥ 65 years, odds ratio (OR) = 0.427], PSA density (≥ 0.20 ng/mL2, OR = 0.234), prior negative biopsy history (OR = 2.231), and PI-RADS score (4, OR = 0.427; 5, OR = 0.071) were independent predictors for the absence of CSPCa by MRIFTB. When assessed according to various conditions, NPVs of PI-RADS 3 lesions were relatively high in subgroups with low PSA density (< 0.20 ng/mL2) regardless of age or prior biopsy history (NPV range 91.1-91.9%). Contrarily, NPVs in subgroups with high PSA density were relatively low and varied according to age or prior biopsy history groups (NPV range 50.0-86.8%). CONCLUSIONS: Men with the PI-RADS 3 lesion and low PSA density might safely evade the MRIFTB, regardless of age or prior biopsy history.

Quantitation of bladder cancer for the prediction of muscle layer invasion as a complement to the vesical imaging-reporting and data system.

OBJECTIVES: To examine the diagnostic performance of Vesical Imaging-Reporting and Data System (VIRADS) and to find a quantitative indicator for predicting muscle layer invasion of bladder cancer. METHODS: 3-T MRI of 82 patients performed before transurethral resection of bladder tumors or radical cystectomy between July 2018 and June 2019 were retrospectively analyzed. For one index lesion of each patient, two radiologists independently assigned VIRADS score and measured tumor-wall interface (contact length between tumor and bladder wall) on T2-weighted, diffusion-weighted, and dynamic contrast-enhanced MRI. Inter-reader agreement was assessed, and logistic regression analysis was performed to find indicators of muscle layer invasion. Comparison of indicators' diagnostic performance was done with receiver operating characteristic (ROC) curve and generalized linear model analyses. Optimal cutoff point was determined by the Youden index J. RESULTS: Inter-reader agreement was at least substantial for VIRADS categorization (κ 0.77-0.81), and almost perfect for tumor-wall interface (intraclass correlation coefficient 0.88-0.90). Tumor-wall interface (odds ratio [OR] 1.90-2.00) and VIRADS score (OR 8.59-8.89) were independently associated with muscle layer invasion (p ≤ 0.02). For VIRADS, area under the ROC curve (AUROC) was 0.94, and the accuracy was 0.93 at score 3, the optimal threshold for predicting muscle layer invasion. Depending on the MRI sequence, tumor-wall interface showed AUROCs of 0.90-0.92 and accuracy of 0.84-0.90 at suggested thresholds (3 ± 0.3 cm). Tumor-wall interface showed insignificant differences in accuracy compared with VIRADS (p > 0.10), except as measured on diffusion-weighted images (p = 0.01). CONCLUSIONS: VIRADS is a good predictor of muscle layer invasion. As an independent quantitative indicator, tumor-wall interface may complement VIRADS to enhance prediction. KEY POINTS: • Vesical Imaging-Reporting and Data System (VIRADS) is a promising predictor of muscle invasion of bladder cancer with good reproducibility, as suggested by previous studies. • VIRADS score and the tumor-wall interface (curvilinear contact length between the tumor and the bladder wall) are independent predictors of muscle layer invasion. • As an easy-to-use quantitative indicator, tumor-wall interface is expected to be used as an indicator complementary to VIRADS, a qualitative indicator.

Favorable intermediate risk prostate cancer with biopsy Gleason score of 6.

BACKGROUND: To identify potential prognostic factors among patients with favorable intermediate risk prostate cancer with a biopsy Gleason score 6. METHODS: From 2003 to 2019, favorable intermediate risk patients who underwent radical prostatectomy were included in this study. All patients were evaluated preoperatively with MRI. Using PI-RADS scores, patients were divided into two groups, and clinic-pathological outcomes were compared. The impact of preoperative factors on significant pathologic Gleason score upgrading (≥ 4 + 3) and biochemical recurrence were assessed via multivariate analysis. Subgroup analysis was performed in patients with PI-RADS ≤ 2. RESULTS: Among the 239 patients, 116 (48.5%) were MRI-negative (PI-RADS ≤ 3) and 123 (51.5%) were MRI-positive (PI-RADS > 3). Six patients in the MRI-negative group (5.2%) were characterized as requiring significant pathologic Gleason score upgrading compared with 34 patients (27.6%) in the MRI-positive group (p < 0.001). PI-RADS score was shown to be a significant predictor of significant pathologic Gleason score upgrading (OR = 6.246, p < 0.001) and biochemical recurrence (HR = 2.595, p = 0.043). 10-years biochemical recurrence-free survival was estimated to be 84.4% and 72.6% in the MRI-negative and MRI-positive groups (p = 0.035). In the 79 patients with PI-RADS ≤ 2, tumor length in biopsy cores was identified as a significant predictor of pathologic Gleason score (OR = 11.336, p = 0.014). CONCLUSIONS: Among the patients with favorable intermediate risk prostate cancer with a biopsy Gleason score 6, preoperative MRI was capable of predicting significant pathologic Gleason score upgrading and biochemical recurrence. Especially, the patients with PI-RADS ≤ 2 and low biopsy tumor length could be a potential candidate to active surveillance.

Transrectal Ultrasound and Photoacoustic Imaging Probe for Diagnosis of Prostate Cancer.

A combined transrectal ultrasound and photoacoustic (TRUS-PA) imaging probe was developed for the clear visualization of morphological changes and microvasculature distribution in the prostate, as this is required for accurate diagnosis and biopsy. The probe consisted of a miniaturized 128-element 7 MHz convex array transducer with 134.5° field-of-view (FOV), a bifurcated optical fiber bundle, and two optical lenses. The design goal was to make the size of the TRUS-PA probe similar to that of general TRUS probes (i.e., about 20 mm), for the convenience of the patients. New flexible printed circuit board (FPCB), acoustic structure, and optical lens were developed to meet the requirement of the probe size, as well as to realize a high-performance TRUS-PA probe. In visual assessment, the PA signals obtained with the optical lens were 2.98 times higher than those without the lens. Moreover, the in vivo experiment with the xenograft BALB/c (Albino, Immunodeficient Inbred Strain) mouse model showed that TRUS-PA probe was able to acquire the entire PA image of the mouse tight behind the porcine intestine about 25 mm depth. From the ex vivo and in vivo experimental results, it can be concluded that the developed TRUS-PA probe is capable of improving PA image quality, even though the TRUS-PA probe has a cross-section size and an FOV comparable to those of general TRUS probes.

Prediction of extraprostatic extension on multi-parametric magnetic resonance imaging in patients with anterior prostate cancer.

OBJECTIVES: To validate how established markers of extraprostatic extension (EPE) are applied to anterior prostate cancers (APCs), and to investigate other novel markers if available. METHODS: Among 614 histopathologically confirmed APCs from 2011 to 2016, 221 lesions with PiRADS (verion 2) scores ≥ 4 on 3-T multi-parametric MRI were analyzed retrospectively. Two radiologists independently assessed capsular morphology qualitatively with 5-point scale (normal, thinning, bulging, loss, extracapsular disease), and capsule contact length (arc), tumor dimension, and their ratio (arc-dimension ratio) quantitatively. Reproducibility in measurement was assessed with κ and intra-class correlation coefficients (ICCs). Logistic regression analysis was done to find meaningful indicators of EPE. Diagnostic performance of markers was compared to one another with generalized linear model and multi-reader multi-case ROC analysis. RESULTS: Reproducibility was moderate to substantial (κ 0.45-0.73) for qualitative, and moderate to almost perfect (ICC 0.50-0.87) for quantitative features of EPE. Capsular morphology (odds ratio [OR] 1.818), capsule contact length (OR 1.115), tumor dimension (OR 1.035), and arc-dimension ratio (OR 1.846) were independently associated with EPE (p ≤ 0.019). Capsular bulging and capsule contact length of 10 mm as thresholds of EPE demonstrated sensitivity/specificity of 0.58/0.85 and 0.77/0.68, respectively. Capsule contact length yielded greatest AUC (0.784), followed by capsular morphology (0.778), arc-dimension ratio (0.749), and tumor dimension (0.741). Diagnostic performance of capsular morphology, capsule contact length, and arc-dimension ratio was comparable in predicting EPE. CONCLUSIONS: Existing markers of EPE applicable regardless of locations of tumors apply similarly to APCs. Arc-dimension ratio may be a novel marker of EPE of APCs. KEY POINTS: • Existing imaging markers of extraprostatic extension (EPE) which have been applied regardless of locations of tumors are reflected similarly to anterior prostate cancers (APCs). • Measuring tumor dimension without capsular assessment may result in insufficient pre-operative prediction of EPE of APCs. • Arc-dimension ratio (capsule contact length divided by tumor dimension) exhibited highest OR and comparable performance to existing features in predicting EPE of APCs.

Development of an ultrasound triggered nanomedicine-microbubble complex for chemo-photodynamic-gene therapy.

Recently, combination therapy has received much attention because of its highly therapeutic effect in various types of cancers. In particular, chemo-photodynamic combination therapy has been considered as an outstanding strategy. However, an abnormal increase in tumor angiogenesis caused by reactive oxygen species (ROS) generated during photodynamic therapy (PDT) has been reported. In this study, the complex of doxorubicin (DOX)-encapsulating anti-angiogenic small interfering RNA (siRNA) nanoparticle and chlorin e6 (Ce6)-encapsulating microbubble has been developed to suppress tumor angiogenesis. The first compartment, doxorubicin-encapsulating siRNA nanoparticle, was electrostatically coated using two biocompatible polymers to prevent the damage of genetic materials. The other part, Ce6-encapsulating microbubble, serves as an ultrasound-triggered local delivery system as well as a drug carrier. Both the in vitro and in vivo experimental results demonstrate successful inhibition of angiogenesis with a minimized damage of siRNAs caused by ROS as well as improved therapeutic effect by chemo-photodynamic-gene triple combination therapy using ultrasound-triggered local delivery.

A Weak and Semi-supervised Segmentation Method for Prostate Cancer in TRUS Images.

The purpose of this research is to exploit a weak and semi-supervised deep learning framework to segment prostate cancer in TRUS images, alleviating the time-consuming work of radiologists to draw the boundary of the lesions and training the neural network on the data that do not have complete annotations. A histologic-proven benchmarking dataset of 102 case images was built and 22 images were randomly selected for evaluation. Some portion of the training images were strong supervised, annotated pixel by pixel. Using the strong supervised images, a deep learning neural network was trained. The rest of the training images with only weak supervision, which is just the location of the lesion, were fed to the trained network to produce the intermediate pixelwise labels for the weak supervised images. Then, we retrained the neural network on the all training images with the original labels and the intermediate labels and fed the training images to the retrained network to produce the refined labels. Comparing the distance of the center of mass of the refined labels and the intermediate labels to the weak supervision location, the closer one replaced the previous label, which could be considered as the label updates. After the label updates, test set images were fed to the retrained network for evaluation. The proposed method shows better result with weak and semi-supervised data than the method using only small portion of strong supervised data, although the improvement may not be as much as when the fully strong supervised dataset is used. In terms of mean intersection over union (mIoU), the proposed method reached about 0.6 when the ratio of the strong supervised data was 40%, about 2% decreased performance compared to that of 100% strong supervised case. The proposed method seems to be able to help to alleviate the time-consuming work of radiologists to draw the boundary of the lesions, and to train the neural network on the data that do not have complete annotations.

Outcomes of magnetic resonance imaging fusion-targeted biopsy of prostate imaging reporting and data system 3 lesions.

PURPOSE: To evaluate the characteristics and histological outcomes in patients with Prostate Imaging Reporting and Data System (PI-RADS) 3 lesions undergoing magnetic resonance imaging-guided fusion-targeted biopsy (MRIFTB). METHODS: We retrospectively reviewed 138 patients with PI-RADS category 3 lesions classified using multiparametric MRI who underwent MRIFTB between May 2016 and March 2018. The study population included biopsy-naïve and patients with prior negative biopsy. Univariate and multivariate analyzes were performed to determine significant predictors of prostate cancer (PCa) and clinically significant prostate cancer (csPCa). The definition of csPCa was set at Gleason score ≥ 3 + 4. RESULTS: Overall, 114 (82.6%) biopsied lesions were benign and 24 (17.4%) were identified as prostate cancer. Of these 24 lesions, 14 (58.3%) harbored csPCa. Peripheral zone (PZ) lesions were more likely to be associated with malignant disease than transition zone lesions (13.7 vs. 6.2%). Multivariate logistic analysis revealed that age, PZ location, and prostate-specific antigen (PSA) density (P < 0.05) were independent predictors of both PCa and csPCa. CONCLUSIONS: A non-negligible number of PI-RADS 3 patients harbor csPCa. Moreover, age, lesion location, and PSA density could be potential clinical predictors of PCa and csPCa. Physicians should be aware of the cancer prevalence of PI-RADS 3 lesions, as the use of the aforementioned factors can help in the decision-making process for these patients.

The Classification of Renal Cancer in 3-Phase CT Images Using a Deep Learning Method.

In this research, we exploit an image-based deep learning framework to distinguish three major subtypes of renal cell carcinoma (clear cell, papillary, and chromophobe) using images acquired with computed tomography (CT). A biopsy-proven benchmarking dataset was built from 169 renal cancer cases. In each case, images were acquired at three phases(phase 1, before injection of the contrast agent; phase 2, 1 min after the injection; phase 3, 5 min after the injection). After image acquisition, rectangular ROI (region of interest) in each phase image was marked by radiologists. After cropping the ROIs, a combination weight was multiplied to the three-phase ROI images and the linearly combined images were fed into a deep learning neural network after concatenation. A deep learning neural network was trained to classify the subtypes of renal cell carcinoma, using the drawn ROIs as inputs and the biopsy results as labels. The network showed about 0.85 accuracy, 0.64-0.98 sensitivity, 0.83-0.93 specificity, and 0.9 AUC. The proposed framework which is based on deep learning method and ROIs provided by radiologists showed promising results in renal cell subtype classification. We hope it will help future research on this subject and it can cooperate with radiologists in classifying the subtype of lesion in real clinical situation.

An ultrasound-responsive dual-modal US/T1 -MRI contrast agent for potential diagnosis of prostate cancer.

BACKGROUND: Interest in an ultrasound-mediated delivery system for effective T1 -MRI of prostate cancer without adverse effects has steadily increased. PURPOSE: To develop an ultrasound-responsive dual-modal ultrasound (US)/T1 -MRI contrast agent for efficient diagnosis of prostate cancer cells overexpressing prostate-specific membrane antigen (PSMA) and assess their potential. STUDY TYPE: In vitro. SUBJECTS: Two prostate cancer cell lines. FIELD STRENGTH/SEQUENCE: Each study group underwent 3.0T MRI under a TR 400 msec, TE 10 msec, a 240 × 240 matrix, a flip angle 90°, a slice thickness 3 mm, NSA with 4, bandwidth 115 Hz/pixel, and an FOV of 120 × 120 mm. ASSESSMENT: Microscopes, quantitative and qualitative analyzing instruments, and clinical devices were used for assessing this novel contrast agent and its diagnosis effects. STATISTICAL TESTS: We used linear regression analyses to determine the longitudinal relaxivity (r1 ) values of our US/T1 -MRI contrast agent and gadobutrol. RESULTS: Microbubble+Fe3+ melanin nanoparticle+peptides (MB+Fe3+ MNPPs) had a good US contrast effect, like a commercial US agent. The differences of US intensities between them was below 5%. The r1 values of MB+Fe3+ MNPPs and gadobutrol were 4.5 and 3.7 s-1 /mM, respectively. More than hundreds of Fe3+ MNPPs were located in prostate cancer cells treated with MB+Fe3+ MNPPs and US stimulus, but the number of Fe3+ MNPPs was below dozens in the other prostate cancer cells expressing less PSMA. The former cells with MB+Fe3+ MNPPs and US stimulus only showed the highest T1 -MRI signal because of synergy effects of the peptides targeting the cells and US stimulus for delivery of Fe3+ MNPPs to the cells. No cytotoxicity of MB+Fe3+ MNPPs was confirmed by using a WST assay. Viability of the cells with the complexes was above 90%. DATA CONCLUSION: We synthesized MB+Fe3+ MNPPs as a potential US/T1 -MRI contrast agent. This complex was applicable for diagnosing desired prostate cancer cells. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;48:1610-1616.

Personalized 3D kidney model produced by rapid prototyping method and its usefulness in clinical applications.

BACKGROUND: Three-dimensional (3D) printing has been introduced as a novel technique to produce 3D objects. We tried to evaluate the clinical usefulness of 3D-printed renal model in performing partial nephrectomy (PN) and also in the education of medical students. MATERIALS AND METHODS: We prospectively produced personalized renal models using 3D-printing methods from preoperative computed tomography (CT) images in a total of 10 patients. Two different groups (urologist and student group) appraised the clinical usefulness of 3D-renal models by answering questionnaires. RESULTS: After application of 3D renal models, the urologist group gave highly positive responses in asking clinical usefulness of 3D-model among PN (understanding personal anatomy: 8.9 / 10, preoperative surgical planning: 8.2 / 10, intraoperative tumor localization: 8.4 / 10, plan for further utilization in future: 8.3 / 10, clinical usefulness in complete endophytic mass: 9.5 / 10). The student group located each renal tumor correctly in 47.3% when they solely interpreted the CT images. After the introduction of 3D-models, the rate of correct answers was significantly elevated to 70.0% (p < 0.001). The subjective difficulty level in localizing renal tumor was also significantly low (52% versus 27%, p < 0.001) when they utilized 3D-models. CONCLUSION: The personalized 3D renal model was revealed to significantly enhance the understanding of correct renal anatomy in patients with renal tumors in both urologist and student groups. These models can be useful for establishing the perioperative planning and also education program for medical students.

Magnetic Resonance Imaging as a Valuable Tool for Predicting Parametrial Invasion in Stage IB1 to IIA2 Cervical Cancer.

OBJECTIVES: The aims of study were to determine the predictive value of preoperative magnetic resonance imaging (MRI) for parametrial invasion (PMI) and to develop a predictive model for PMI in patients with stage IB1 to IIA2 cervical cancer. METHODS: We retrospectively analyzed patients with stage IB1 to IIA2 cervical cancer (n = 215) who underwent radical hysterectomy between 2003 and 2014. The presence of PMI from postoperative pathological reports and its association with preoperative MRI findings were evaluated. We developed a predictive model for PMI using independent predictive factors identified by logistic regression and estimated its predictive performance. RESULTS: Thirty patients (14.0%) had PMI from postoperative pathological reports. Among the preoperative MRI findings, a greater tumor diameter (4.2 vs 2.0 cm; P < 0.001), a larger tumor volume (92.6 vs 12.7 cm; P < 0.001), the presence of PMI (53.3% vs 8.6%; P < 0.001), and upper vaginal involvement (73.3% vs 22.7%; P < 0.001) were significantly associated with PMI. Multivariate analysis identified tumor volume (odds ratio, 7.0; 95% confidence interval, 2.63-18.53; P < 0.001) and PMI (odds ratio, 6.1; 95% confidence interval, 2.31-15.97; P < 0.001) from preoperative MRI findings as independent predictive factors for PMI. Our predictive model demonstrates that the presence of PMI or a tumor volume of greater than 18.0 cm has a higher sensitivity (86.7% vs 53.3%) and lower specificity (74.6% vs 91.4%) than the presence of PMI alone. Specifically, the model's negative predictive value was superior to that of PMI only (97.2% vs 92.3%). In the low-risk group, defined as preoperative MRI findings suggesting no PMI and a tumor volume of 18.0 cm or less, the proportion of false negative cases was just 2.8%. CONCLUSIONS: When tumor volume with findings suggesting that PMI is considered, preoperative MRI is useful in excluding PMI. A predictive model based on preoperative MRI findings seems to be valuable in identifying potential candidates for less radical surgery in stage IB1 to IIA2 cervical cancer.

Elastographic Strain Index in the Evaluation of Focal Lesions Detected With Transrectal Sonography of the Prostate Gland.

OBJECTIVES: The purpose of this study was to evaluate the value of elastography in evaluating focal lesions detected by transrectal sonography and to suggest a reference strain index. METHODS: Sixty-nine patients with focal lesions on transrectal sonography were referred to our department for prostate biopsy. Focal lesions were classified as either highly or less suspicious lesions by our criteria. A strain index from elastography was calculated for the focal lesions. Systematic 12-core randomized biopsies plus 2 targeted biopsies were performed. The mean strain indices for malignant and benign focal lesions were compared, and a cutoff strain index was attained to maximize the sensitivity and specificity for prostate cancer. Strain indices were correlated with Gleason scores. RESULTS: The mean strain index ± SD for malignant focal lesions (3.26 ± 1.77) was significantly higher than that for benign focal lesions (2.16 ± 1.52; P = .008). The sensitivity, specificity, and area under the receiver operating characteristic curve for diagnosing cancer were 66.7%, 71.1%, and 0.701, respectively, at a strain index cutoff value of greater than 2.4. The strain index showed a moderate linear correlation with the Gleason score (r = 0.441; P = .013). CONCLUSIONS: Any focal lesion on transrectal sonography with a strain index of greater than 2.4 is at risk for prostate cancer.

Multiparametric monitoring of early response to antiangiogenic therapy: a sequential perfusion CT and PET/CT study in a rabbit VX2 tumor model.

OBJECTIVES: To perform dual analysis of tumor perfusion and glucose metabolism using perfusion CT and FDG-PET/CT for the purpose of monitoring the early response to bevacizumab therapy in rabbit VX2 tumor models and to assess added value of FDG-PET to perfusion CT. METHODS: Twenty-four VX2 carcinoma tumors implanted in bilateral back muscles of 12 rabbits were evaluated. Serial concurrent perfusion CT and FDG-PET/CT were performed before and 3, 7, and 14 days after bevacizumab therapy (treatment group) or saline infusion (control group). Perfusion CT was analyzed to calculate blood flow (BF), blood volume (BV), and permeability surface area product (PS); FDG-PET was analyzed to calculate SUVmax, SUVmean, total lesion glycolysis (TLG), entropy, and homogeneity. The flow-metabolic ratio (FMR) was also calculated and immunohistochemical analysis of microvessel density (MVD) was performed. RESULTS: On day 14, BF and BV in the treatment group were significantly lower than in the control group. There were no significant differences in all FDG-PET-derived parameters between both groups. In the treatment group, FMR prominently decreased after therapy and was positively correlated with MVD. CONCLUSIONS: In VX2 tumors, FMR could provide further insight into the early antiangiogenic effect reflecting a mismatch in intratumor blood flow and metabolism.

Tumor suppression effect of ultrasound-sensitive nanoparticles with focused ultrasound in a pancreas cancer xenograft model.

BACKGROUND: We investigated the tumor suppression effect of an ultrasound-sensitive doxorubicin-loaded liposome-based nanoparticle, IMP301, to enhance the synergistic effect with focused ultrasound (FUS) in an animal model of pancreatic cancer. METHODS: Thirty nude mice with xenografts of PANC-1 human pancreatic cancer cells were randomly and prospectively allocated to 6 different groups (5 per group) each for Study-1 (dose-response test) and Study-2 (synergistic effect test). Study-1 consisted of control, gemcitabine, Doxil with FUS, and three different doses of IMP301 (2, 4, 6 mg/kg) with FUS groups. Study-2 consisted of control, FUS only, gemcitabine, Doxil with FUS, and IMP301 (4 mg/kg) with or without FUS groups. Differences in tumor volume and growth rate were evaluated by one-way ANOVA and Student-Newman-Keuls test. RESULTS: In Study-1, 4 mg/kg or greater IMP301 with FUS groups showed lower tumor growth rates of 14 ± 4 mm3/day (mean ± standard deviation) or less, compared to the control, gemcitabine, and Doxil with FUS groups with rates exceeding 28 ± 5 (p < 0.050). The addition of FUS in Study-2 decreased the tumor growth rate in the IMP301-treated groups from 36 ± 17 to 9 ± 6, which was lower than the control, FUS only, gemcitabine, and Doxil with FUS groups (p < 0.050). CONCLUSIONS: IMP301 combined with FUS exhibited higher tumor growth suppression compared to the use of a conventional drug alone or the combination with FUS. The present study showed the potential of IMP301 to enhance the synergistic effect with FUS for the treatment of pancreatic cancer. RELEVANCE STATEMENT: This article aims to evaluate the synergistic effect of FUS and ultrasound-responsive liposomal drug in tumor growth suppression by using xenograft mouse model of pancreatic ductal adenocarcinoma. FUS-induced ultrasound-sensitive drug release may be a potential noninvasive repeatable treatment option for patients with locally advanced or unresectable pancreatic cancer. KEY POINTS: • Modification of conventional drugs combined with FUS would maximize tumor suppression. • IMP301 with FUS had higher tumor suppression effect compared to conventional chemotherapy. • This image-guided drug delivery would enhance therapeutic effects of systemic chemotherapy.

Effect of dorsal vascular complex size on the recovery of continence after radical prostatectomy.

PURPOSE: The dorsal vascular complex (DVC) of the prostate is considered to be a functional structure having smooth muscles that are connected to the detrusor apron. We conducted this study to provide basic information regarding DVC size as measured by magnetic resonance imaging and to investigate whether DVC size is related to the recovery of continence following radical prostatectomy (RP). METHODS: We prospectively collected data that included the results of prostate MRI and continence recovery of patients who underwent RP. From April 2006 through February 2010, 862 patients underwent RP. Of these, a total of 731 cases were included in the final analysis. The height and width of the DVC were measured in the T1-weighted axial image at the level that showed the puboprostatic ligament. RESULTS: The continence rate of the total patient cohort at 12 months was 96.7 %. The mean width, height and area of the DVC were 2.0 ± 0.4 cm, 1.2 ± 0.3 cm and 1.8 ± 0.6 cm(2), respectively, and there was no linear correlation between continence recovery and these parameters. However, the patients who had a moderately large-sized DVC (2.3-2.8 cm(2)) regained their continence significantly sooner (mean duration = 2.1 months) than those with small (3.7 months, p = 0.002) or extremely large DVC (4.0 months, p = 0.006). In a multivariate analysis, DVC size, age, transfusion and the length of membranous urethra were significant predictors of continence recovery. CONCLUSION: The patients who had a moderately large DVC regained continence faster following RP.