Multispecies comparative prostate anatomy by imaging: Implications for experimental models of prostatic disease.

BACKGROUND: There is an increasing interest in using preclinical models for development and assessment of medical devices and imaging techniques for prostatic disease care. Still, a comprehensive assessment of the prostate's radiological anatomy in primary preclinical models such as dogs, rabbits, and mice utilizing human anatomy as a reference point remains necessary with no optimal model for each purpose being clearly defined in the literature. Therefore, this study compares the anatomical characteristics of different animal models to the human prostatic gland from the imaging perspective. METHODS: We imaged five Beagle laboratory dogs, five New Zealand White rabbits, and five mice, all sexually mature males, under Institutional Animal Care and Use Committee (IACUC) approval. Ultrasonography (US) was performed using the Vevo® F2 for mice (57 MHz probe). Rabbits and dogs were imaged using the Siemens® Acuson S3000 (17 MHz probe) and endocavitary (8 MHz) probes, respectively. Magnetic resonance imaging (MRI) was also conducted with a 7T scanner in mice and 3T scanner in rabbits and dogs. RESULTS: Canine transrectal US emerged as the optimal method for US imaging, depicting a morphologically similar gland to humans but lacking echoic zonal differentiation. MRI findings in canines indicated a homogeneously structured gland similar to the human peripheral zone on T2-weighted images (T2W) and apparent diffusion coefficient (ADC). In rabbits, US imaging faced challenges due to the pubic symphysis, whereas MRI effectively visualized all structures with the prostate presenting a similar aspect to the human peripheral gland on T2W and ADC maps. Murine prostate assessment revealed poor visualization of the prostate glands in ultrasound due to its small size, while 7T MRI delineated the distinct prostates and its lobes, with the lateral and dorsal prostate resembling the peripheral zone and the anterior prostate the central zone of the human gland. CONCLUSION: Dogs stand out as superior models for advanced preclinical studies in prostatic disease research. However, mice present as a good model for early stage studies and rabbits are a cost-effective alternative and serve as valuable tools in specific research domains when canine research is not feasible.

Diagnostic Accuracy of MRI in Local Staging (T Category) of Penile Cancer and the Value of Artificial Erection: A Systematic Review and Meta-Analysis.

BACKGROUND. Treatment recommendations of penile cancers are determined primarily by the local extent of the primary tumor. Clinical palpation is used for local staging. OBJECTIVE. We reviewed diagnostic performance of MRI in local staging of penile cancer in three clinical scenarios (questions [Qs] 1 through 3, Q1-Q3) and one imaging scenario (Q4). Q1 asked whether MRI reliably distinguishes ≤ T1 from ≥ T2 disease. Q2 asked whether clinical staging reliably identifies ≤ T1 versus ≥ T2 disease and how clinical staging compares to MRI. Q3 asked if MRI is accurate for diagnosis of T3 disease. Q4 asked if artificial erection (by intracavernosal injection of prostaglandin E1) improved accuracy of MRI in T categorization. EVIDENCE ACQUISITION. MEDLINE, EMBASE, and Cochrane Library databases were searched through September 13, 2021, for studies evaluating local staging of penile cancer using MRI with surgical pathology as the reference standard. Diagnostic accuracy was calculated using a bivariate random-effects model and hierarchic summary ROC mode Meta-regression was performed to test for covariate effects of MRI and artificial erection in Q3 and Q4, respectively. EVIDENCE SYNTHESIS. Eight studies and 481 patients were included. The sensitivity and specificity of MRI for Q1 were 86% (95% CI, 73-94%) and 89% (95% CI, 77-95%), respectively. AUC for MRI (0.94; 95% CI, 0.92-0.96) did not differ from clinical staging (0.87; 95% CI, 0.84-0.90; p = .83). For Q3, MRI had sensitivity and specificity of 80% (95% CI, 70-87%) and 96% (95% CI, 85-99%), respectively. For Q4, sensitivity and specificity for MRI with versus without artificial erection were 85% (95% CI, 71-92%) and 93% (95% CI, 77-98%) versus 86% (95% CI, 68-95%) and 84% (95% CI, 70-93%), respectively (p = .50). CONCLUSION. MRI staging of penile cancer may be considered for ≤ T1 versus ≥ T2 disease but did not appear more accurate than clinical staging. High specificity of MRI for diagnosis of ≥ T3 disease suggests that MRI may be useful when organ-sparing approaches are planned. MRI with and without artificial erection showed similar accuracy in local staging. CLINICAL IMPACT. MRI, with or without artificial erection, may be valuable in routine preoperative evaluation of local staging of penile cancer, particularly when organ-sparing options are considered.

Update on MRI of Cystic Renal Masses Including Bosniak Version 2019.

Incidental cystic renal masses are common, usually benign, and almost always indolent. Since 1986, the Bosniak classification has been used to express the risk of malignancy in a cystic renal mass detected at imaging. Historically, magnetic resonance imaging (MRI) was not included in that classification. The proposed Bosniak v.2019 update has formally incorporated MRI, included definitions of imaging terms designed to improve interobserver agreement and specificity for malignancy, and incorporated a variety of masses that were incompletely defined or not included in the original classification. For example, at unenhanced MRI, homogeneous masses markedly hyperintense at T2 -weighted imaging (similar to cerebrospinal fluid) and homogeneous masses markedly hyperintense at fat suppressed T1 -weighted imaging (approximately ≥2.5 times more intense than adjacent renal parenchyma) are classified as Bosniak II and may be safely ignored, even when they have not been imaged with a complete renal mass MRI protocol. MRI has specific advantages and is recommended to evaluate masses that at computed tomography (CT) 1) have abundant thick or nodular calcifications; 2) are homogeneous, hyperattenuating, ≥3 cm, and nonenhancing; or 3) are heterogeneous and nonenhancing. Although MRI is generally excellent for characterizing cystic renal masses, there are unique weaknesses of MRI that bear consideration. These details and others related to MRI of cystic renal masses are described in this review, with an emphasis on Bosniak v.2019. A website (https://bosniak-calculator.herokuapp.com/) and mobile phone apps named "Bosniak Calculator" have been developed for ease of assignment of Bosniak classes. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

PI-RADS Version 2.1: A Critical Review, From the AJR Special Series on Radiology Reporting and Data Systems.

PI-RADS version 2.1 updates the technical parameters for multiparametric MRI (mpMRI) of the prostate and revises the imaging interpretation criteria while maintaining the framework introduced in version 2. These changes have been considered an improvement, although some issues remain unresolved, and new issues have emerged. Areas for improvement discussed in this review include the need for more detailed mpMRI protocols with optimization for 1.5-T and 3-T systems; lack of validation of revised transition zone interpretation criteria and need for clarifications of the revised DWI and dynamic contrast-enhanced imaging criteria and central zone (CZ) assessment; the need for systematic evaluation and reporting of background changes in signal intensity in the prostate that can negatively affect cancer detection; creation of a new category for lesions that do not fit into the PI-RADS assessment categories (i.e., PI-RADS M category); inclusion of quantitative parameters beyond size to evaluate lesion aggressiveness; adjustments to the structured report template, including standardized assessment of the risk of extraprostatic extension; development of parameters for image quality and performance control; and suggestions for expansion of the system to other indications (e.g., active surveillance and recurrence).

Bosniak Classification of Cystic Renal Masses, Version 2019: A Pictorial Guide to Clinical Use.

Cystic renal masses are commonly encountered in clinical practice. In 2019, the Bosniak classification of cystic renal masses, originally developed for CT, underwent a major revision to incorporate MRI and is referred to as the Bosniak Classification, version 2019. The proposed changes attempt to (a) define renal masses (ie, cystic tumors with less than 25% enhancing tissue) to which the classification should be applied; (b) emphasize specificity for diagnosis of cystic renal cancers, thereby decreasing the number of benign and indolent cystic masses that are unnecessarily treated or imaged further; (c) improve interobserver agreement by defining imaging features, terms, and classes of cystic renal masses; (d) reduce variation in reported malignancy rates for each of the Bosniak classes; (e) incorporate MRI and to some extent US; and (f) be applicable to all cystic renal masses encountered in clinical practice, including those that had been considered indeterminate with the original classification. The authors instruct how, using CT, MRI, and to some extent US, the revised classification can be applied, with representative clinical examples and images. Practical tips, pitfalls to avoid, and decision tree rules are included to help radiologists and other physicians apply the Bosniak Classification, version 2019 and better manage cystic renal masses. An online resource and mobile application are also available for clinical assistance. An invited commentary by Siegel and Cohan is available online. ©RSNA, 2021.

Interobserver agreement of PI-RADS v. 2 lexicon among radiologists with different levels of experience.

BACKGROUND: Evaluation of interobserver agreement of the PI-RADS v2 lexicon is important to validate the uniformity of this widely used classification. PURPOSE: To determine the interobserver agreement of PI-RADS v2 lexicon among eight radiologists with varying levels of experience. STUDY TYPE: Retrospective. POPULATION: In all, 160 consecutively imaged men with confirmatory targeted biopsy. FIELD STRENGTH/SEQUENCE: 3T scanner without an endorectal coil. T2 -weighted imaging (T2 w), diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) map and dynamic contrast-enhanced sequence were performed. ASSESSMENT: Eight radiologists (two highly experienced, two moderately experienced, and four less experienced) independently read 130 lesions in the peripheral zone (PZ) and 30 lesions in the transition zone (TZ), blinded to clinical MRI indication and biopsy results. The features described in PI-RADS v2 for TZ and PZ lesions were evaluated. STATISTICAL TESTS: Conger's kappa, percentage of concordance, and first-order agreement coefficient (AC1) were used to evaluate interobserver agreement. RESULTS: From the features evaluated on PZ lesions, definite extraprostatic extension (EPE) / invasive behavior on T2 w had good agreement (AC1 = 0.80), and the others had fair agreement (AC1 = 0.32-0.40). From the features evaluated on TZ lesions, two had good agreement: definite EPE/invasive behavior (AC1 = 0.77) and moderate/marked hypointensity (AC1 = 0.67) on T2 w. Encapsulation and lenticular shape on T2 w, focal (not indistinct) on DWI and ADC map, and marked hypointensity on ADC map (AC1 = 0.45 to 0.60) had moderate agreement, whereas heterogeneous and circumscribed (not obscured margins) on T2 w, marked hyperintensity on high-b-value DWI, and the presence or not of early enhancement in the lesion/region of the lesion (AC1 = 0.30 to 0.38) had fair agreement. DATA CONCLUSION: Interobserver agreement in PI-RADS v2 lexicon ranges from fair to good among radiologists and improves with increasing experience. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:593-602.

Data Augmentation and Transfer Learning to Improve Generalizability of an Automated Prostate Segmentation Model.

OBJECTIVE. Deep learning applications in radiology often suffer from overfitting, limiting generalization to external centers. The objective of this study was to develop a high-quality prostate segmentation model capable of maintaining a high degree of performance across multiple independent datasets using transfer learning and data augmentation. MATERIALS AND METHODS. A retrospective cohort of 648 patients who underwent prostate MRI between February 2015 and November 2018 at a single center was used for training and validation. A deep learning approach combining 2D and 3D architecture was used for training, which incorporated transfer learning. A data augmentation strategy was used that was specific to the deformations, intensity, and alterations in image quality seen on radiology images. Five independent datasets, four of which were from outside centers, were used for testing, which was conducted with and without fine-tuning of the original model. The Dice similarity coefficient was used to evaluate model performance. RESULTS. When prostate segmentation models utilizing transfer learning were applied to the internal validation cohort, the mean Dice similarity coefficient was 93.1 for whole prostate and 89.0 for transition zone segmentations. When the models were applied to multiple test set cohorts, the improvement in performance achieved using data augmentation alone was 2.2% for the whole prostate models and 3.0% for the transition zone segmentation models. However, the best test-set results were obtained with models fine-tuned on test center data with mean Dice similarity coefficients of 91.5 for whole prostate segmentation and 89.7 for transition zone segmentation. CONCLUSION. Transfer learning allowed for the development of a high-performing prostate segmentation model, and data augmentation and fine-tuning approaches improved performance of a prostate segmentation model when applied to datasets from external centers.

When to Biopsy the Seminal Vesicles: A Validated Multiparametric Magnetic Resonance Imaging and Target Driven Model to Detect Seminal Vesicle Invasion of Prostate Cancer.

PURPOSE: Current imaging and biopsy practices offer limited insight into preoperative detection of seminal vesicle invasion despite the implications for treatment decisions and patient prognoses. We identified magnetic resonance imaging features to assess the risk of seminal vesicle invasion and inform the inclusion of seminal vesicle sampling during biopsy. MATERIALS AND METHODS: Patients underwent multiparametric magnetic resonance imaging and fusion targeted biopsy with or without seminal vesicle biopsy. Magnetic resonance imaging suspicion of seminal vesicle invasion, multiparametric magnetic resonance imaging of prostate base lesions of moderate or greater suspicion, extraprostatic extension, anatomical zone and biopsy data were used to generate multivariable logistic regression models. One model without and one with biopsy data were externally validated in a multi-institutional cohort. Decision curve analyses were done to determine net benefit of the 2 models. RESULTS: The training and validation cohorts comprised 564 and 250 patients, respectively. In the training cohort 55 patients (9.8%) had pathologically confirmed seminal vesicle invasion. In the prebiopsy model magnetic resonance imaging suspicion of seminal vesicle invasion (OR 9.5, 95% CI 4.0-22.4, p <0.001), multiparametric magnetic resonance imaging base lesions of moderate or greater suspicion with extraprostatic extension (OR 13.6, 95% CI 4.0-46.5, p <0.001), and a transition and/or central zone location (OR 11.6, 95% CI 3.5-38.3, p <0.001) showed strong correlations. In the post-biopsy model the risk of pathologically confirmed seminal vesicle invasion increased with the base Gleason Group (Gleason Group 5 OR 85.3, 95% CI 11.8-619.1, p <0.001). In the validation cohort the AUC of the prebiopsy and post-biopsy models was 0.84 and 0.93, respectively (p = 0.030). CONCLUSIONS: Magnetic resonance imaging evidence of seminal vesicle invasion or extraprostatic extension at the prostate base transition and/or central zone and high grade prostate cancer from the prostate base are significant features associated with an increased risk of pathologically confirmed seminal vesicle invasion. Our models successfully incorporated these features to predict seminal vesicle invasion and inform when to biopsy the seminal vesicles.

Imaging Findings in Transgender Patients after Gender-affirming Surgery.

Gender-affirming surgeries expand the options for physical transition among transgender patients, those whose gender identity is incongruent with the sex assigned to them at birth. Growing medical insight, increasing public acceptance, and expanding insurance coverage have improved the access to and increased the demand for gender-affirming surgeries in the United States. Procedures for transgender women, those patients with feminine gender identity, include breast augmentation using implants and genital reconstruction with vaginoplasty. Some transgender women receive medically unapproved silicone injections for breast augmentation or other soft-tissue contouring procedures that can lead to disfigurement, silicone pulmonary embolism, systemic reactions, and even death. MRI is preferred over CT for postvaginoplasty evaluation given its superior tissue contrast resolution. Procedures for transgender men, patients with a masculine gender identity, include chest masculinization (mastectomy) and genital reconstruction (phalloplasty or metoidioplasty, scrotoplasty, and erectile device implantation). Urethrography is the standard imaging modality performed to evaluate neourethral patency and other complications, such as leaks and fistulas. Despite a sizeable growth in the surgical literature about gender-affirming surgeries and their outcomes, detailed descriptions of the imaging features following these surgeries remain sparse. Radiologists must be aware of the wide variety of anatomic and pathologic changes unique to patients who undergo gender-affirming surgeries to ensure accurate imaging interpretation. Online supplemental material is available for this article. ©RSNA, 2019.

Incremental diagnostic value of targeted biopsy using mpMRI-TRUS fusion versus 14-fragments prostatic biopsy: a prospective controlled study.

OBJECTIVES: To compare the incremental diagnostic value of targeted biopsy using real-time multiparametric magnetic resonance imaging and transrectal ultrasound (mpMRI-TRUS) fusion to conventional 14-cores biopsy. PATIENTS AND METHODS: Uni-institutional, institutional review board (IRB) approved prospective blinded study comparing TRUS-guided random and targeted biopsy using mpMRI-TRUS fusion, in 100 consecutive men. We included men with clinical-laboratorial suspicious for prostate cancer and Likert score ≥ 3 mp-MRI. Patients previously diagnosed with prostate cancer were excluded. All patients were submitted to 14-cores TRUS-guided biopsy (mpMRI data operator-blinded), followed by targeted biopsy using mpMRI-TRUS fusion. RESULTS: There was an overall increase in cancer detection rate, from 56% with random technique to 62% combining targeted biopsy using mpMRI-TRUS fusion; incremental diagnosis was even more relevant for clinically significant lesions (Gleason ≥ 7), diagnosing 10% more clinically significant lesions with fusion biopsy technique. Diagnosis upgrade occurred in 5 patients that would have negative results in random biopsies and had clinically significant tumours with the combined technique, and in 5 patients who had the diagnosis of significant tumours after fusion biopsy and clinically insignificant tumours in random biopsies(p=0.0010). CONCLUSIONS: Targeted biopsy using mpMRI-TRUS fusion has incremental diagnostic value in comparison to conventional random biopsy, better detecting clinically significant prostate cancers. KEY POINTS: • mpMRI-TRUS targeted biopsy increases overall cancer detection rate, but not statistically significant. • mpMRI-TRUS targeted biopsy actually improves the diagnosis of clinically significant PCa. • There was no evidence to acquire the mpMRI-TRUS fusion cores alone.

Evaluation of Posterior Cruciate Ligament and Intercondylar Notch in Subjects With Anterior Cruciate Ligament Tear: A Comparative Flexed-Knee 3D Magnetic Resonance Imaging Study.

PURPOSE: To determine if posterior cruciate ligament (PCL) and intercondylar notch (IN) morphometries and volumetrics act as risk factors for anterior cruciate ligament (ACL) tears. METHODS: A prospective case-controlled magnetic resonance imaging (MRI) study was conducted with subjects presenting noncontact knee injuries. Exclusion criteria were previous surgery, PCL tear, osteoarthritis, tumors, or infectious and inflammatory conditions. All participants underwent a flexed-knee 3-dimensional (3D) magnetic resonance imaging (MRI) to uniformly straighten PCL. MR images were independently reviewed by 2 radiologists and assessed for 2D and 3D measurements (bicondylar width; IN angle, depth, width, and cross-sectional area; PCL width, thickness, and cross-sectional area; and IN and PCL volumes). Clinical profiles were tabulated and subjects were divided into cases (ACL tear) and controls (without ACL tear). RESULTS: The study was composed of 50 cases versus 52 controls (N = 102), with a mean age of 36.8 years. There was no difference between groups (P > .05) regarding age, gender, body mass index, time from injury, Tegner score, flexion angle, limb side, intensity of injury, or familial or opposite limb history of tear. Agreement between readers ranged from substantial to almost perfect. Subjects with ACL tear presented with lower IN width, lower IN minus PCL widths, lower Notch Width Index, higher PCL/IN width proportion, higher PCL thickness, lower IN depth minus PCL thickness, and higher PCL thickness/IN depth proportion (P < .05). Moreover, higher PCL/IN cross-sectional area proportion, higher PCL volumes (OR = 9.01), and higher PCL/IN volume proportion were also found in cases. CONCLUSIONS: Our study shows that subjects with ACL tears present not only reduced IN but also larger PCL dimensions. These findings, isolated and combined, and especially PCL volume, might be suggestive as risk factors for ACL tears owing to the reduction of its space inside the IN. LEVEL OF EVIDENCE: Level III, comparative group.

Malignancy Rate, Histologic Grade, and Progression of Bosniak Category III and IV Complex Renal Cystic Lesions.

OBJECTIVE: The primary purpose of this study is to determine the malignancy rate, histologic grade, and initial stage of surgically treated complex renal cysts classified as Bosniak category III or IV. For nonsurgical lesions, a secondary objective was to evaluate lesion progression on follow-up examinations. MATERIALS AND METHODS: We searched our database for cystic lesions classified as Bosniak III or IV category on CT or MRI from January 2008 to April 2016. Surgically resected lesions, per category, were correlated with information on pathologic reports to obtain malignancy rates. For malignant lesions, histologic grade and initial stage were evaluated. Imaging follow-up of at least 2 years was used to evaluate progression of clinically followed lesions. RESULTS: We included 86 lesions in 85 patients in the final analysis. Of the 60 surgically resected lesions (70%), 46 (77%) were malignant and 14 (23%) were benign. Malignancy rates were 72% for Bosniak category III lesions and 86% for Bosniak category IV lesions. Most malignant cysts were early-stage (pT1) cysts with low histologic grades (89% of Bosniak III lesions and 91% of Bosniak IV lesions). Follow-up studies of the surgically resected lesions did not show local recurrence, metastasis, or lymph node enlargement. Among patients with lesions managed by watchful waiting (n = 26), all lesions remained unchanged in terms of size and complexity after at least 2-years of follow-up. CONCLUSION: Although high malignancy rates were observed for both Bosniak category III and IV lesions, our results suggest that such malignant cysts are usually early-stage tumors with a low histologic grade. Lesions that underwent follow-up remained unchanged on control examinations. These findings may indicate low aggressiveness of these lesions, supporting the idea that more conservative approaches may be used.

MRI findings after prostatic artery embolization for treatment of benign hyperplasia.

OBJECTIVE: The purpose of this article is to assess and describe the MRI findings after prostatic artery embolization for treatment of benign prostatic hyperplasia. MATERIALS AND METHODS: We retrospectively evaluated 17 patients who underwent prostatic artery embolization as part of different prospective studies to evaluate this alternative treatment of benign prostatic hyperplasia. Clinical results were evaluated by assessment of urinary catheterization and International Prostate Symptom Score (IPSS). Serial MRI examinations were performed, and the prostatic central gland and peripheral zone were evaluated for signal intensity changes and the presence and characteristics of infarcted areas. Statistical analysis was performed with ANOVA for repeated measures and Student t test. RESULTS: All patients had clinical success, as defined by the removal of indwelling urinary catheter or decreased IPSS after embolization. Infarcts were seen in 70.6% of the subjects, exclusively in the central gland, were almost always characterized by hyperintensity on T1-weighted images and predominant hypointensity on T2-weighted images, and became smaller (mean reduction, p < 0.001) and isointense to the remaining of the central gland over time. Volume reduction of the prostate after embolization was significant (averaging 32.0% after 12-18 months; p < 0.001) only in patients with infarcts. No statistically significant association was seen between the development of infarcts and IPSS. CONCLUSION: MRI can be used for assessing the development of infarcts and volume reduction in the prostate after embolization. Further studies are needed to correlate these findings to clinical outcome.

Quality of life and clinical symptom improvement support prostatic artery embolization for patients with acute urinary retention caused by benign prostatic hyperplasia.

PURPOSE: To show that prostatic artery embolization (PAE) improves quality of life (QoL) and lower urinary tract symptoms in patients with acute urinary retention caused by benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: This was a single-center prospective study of PAE in 11 patients with BPH managed with indwelling urinary catheters. International Prostate Symptom Score (IPSS), ultrasound, magnetic resonance (MR) imaging, QoL, and urodynamic tests were used to assess outcomes. Prostate size ranged from 30 to 90 g, and embolizations were performed with 300-500-µm Embosphere microspheres. RESULTS: The rate of technical success (ie, bilateral PAE) was 75%, and the rate of clinical success (ie, catheter removal and symptom improvement) was 91% (10 of 11 patients). Postembolization syndrome manifested as mild pain in the perineum, retropubic area, and/or urethra. Ten of 11 patients urinated spontaneously after Foley catheter removal 4-25 days after PAE (mean, 12.1 d). No major complications were observed. Follow-up ranged from 19 to 48 months. In an asymptomatic patient, a discrete area of hypoperfusion suggesting small ischemia of the bladder was observed on 30-day MR imaging follow-up, but the bladder was normal on 90-day MR imaging. After 1 year, mean prostate volume reduction was greater than 30%, symptoms were mild (mean IPSS, 2.8 ± 2.1; P = .04), no erectile dysfunction was observed, and QoL improved significantly (mean, 0.4 ± 0.5; P = .001) using the paired t test. CONCLUSIONS: Patients with severe symptoms and acute urinary retention caused by BPH can be treated safely by PAE, which improves clinical symptoms and QoL.

Accuracy of 68Ga-PSMA PET/CT for lymph node and bone primary staging in prostate cancer.

PURPOSE: The aim of this study is to assess the accuracy of the 68Ga-PSMA PET/CT for lymph nodes and bones in the primary stage of prostate cancer. METHODS: A total of 126 patients who were submitted to 68Ga-PSMA PET/CT from January 2016 to February 2019 for prostate cancer staging, detection of clinically significant lesions or active surveillance were included in this study. All studies were read by 2 experienced physicians (a nuclear physician and a radiologist). The reports were made in consensus and used by one of the authors to classify the exam in positive or negative. We evaluated presence of abnormal uptake in the prostate, lymph nodes, and bone. The reference standards were histopathological confirmation, confirmatory imaging exams and/or clinical follow-up showing lesion(s) regression after specific treatment, or typical osseous metastatic lesions and highly increased PSA levels. RESULTS: Measurement of diagnostic performance indicated a sensitivity, specificity and accuracy of 75%, 96.3%, and 90.8%, respectively, for lymph node involvement, and 90.9%, 50%, and 76.5%, respectively for metastatic bone lesions. CONCLUSION: This study showed high specificity and accuracy of 68Ga-PSMA PET/CT for lymph node and bone involvement in prostate cancer staging.

Which criteria can be used to predict benignity in solid renal lesions lower-equal to 2 cm?

PURPOSE: To evaluate magnetic resonance imaging (MRI) criteria of solid renal lesions lower-equal to 2 cm to differentiate benign and malignant tumors, using histopathology as gold standard. METHODS: Three radiologists independently evaluated objective and subjective MRI criteria of focal renal lesions. A total of 105 nodules of patients who had MRI and histopathological results in our institution were included. Subjective criteria evaluated were signal on T2-weighted imaging, presence of microscopic and macroscopic fat, hemosiderin, hemorrhage, central scar, segmented inversion enhancement and enhancement type; objective criteria were gender, ADC value, heterogeneity on T2-weighted imaging and proportion of enhancement in late post-contrast phases. Finally, the readers classified the lesions in probably benign or malignant. Interobserver agreement was evaluated by the Gwet method, and the quantitative variables by intraclass correlation coefficients. To adjust the predictive model, the logistic regression model was used considering the benignity variable as outcome. RESULTS: A total of 26 nodules (24.5%) were benign and 79 (75.2%) were malignant, with size ranging from 7 to 20 mm (median: 14 mm). The most frequent subtype was papillary renal cell carcinoma (RCC) (35.2%), followed by clear-cell RCC (24.8%) and oncocytoma (12.4%). The univariate and multivariate analysis showed, among all categories evaluated, that microscopic fat (p: 0.072), intermediate (p: 0.004) and hyper-enhancement (p: 0.031) and female sex (p: 0.0047) had the best outcome for benignity, within odds ratios of 4.29, 5.75, 4.07 and 2.86, respectively. CONCLUSION: In small solid renal lesions lower-equal to 2 cm, microscopic fat, moderate and hyper-enhancement and female sex were associated with benignity.

Prostate magnetic resonance imaging technique.

Multiparametric magnetic resonance (MR) imaging of the prostate is an excellent tool to detect clinically significant prostate cancer, and it has widely been incorporated into clinical practice due to its excellent tissue contrast and image resolution. The aims of this article are to describe the prostate MR imaging technique for detection of clinically significant prostate cancer according to PI-RADS v2.1, as well as alternative sequences and basic aspects of patient preparation and MR imaging artifact avoidance.

MR imaging findings of iron overload.

Hemochromatosis can be classified as (a) primary, when it originates from a genetic disturbance that promotes the increase of iron absorption, or (b) secondary, when it relates to chronic diseases or to multiple transfusions. The distribution of iron accumulation differs between these two forms; therefore, they can be distinguished by using imaging methods in the majority of cases. Magnetic resonance (MR) imaging is the most sensitive and specific imaging modality in the diagnosis of hemochromatosis. The susceptibility effect caused by the accumulation of iron leads to signal loss in the affected tissues, particularly with the T2*-weighted sequences, which makes the diagnosis of iron overload possible. By using MR imaging techniques, it is possible to estimate the hepatic iron concentration in a noninvasive way, thereby avoiding repeated biopsies. Hemochromatosis can lead to complications, such as a higher frequency of neoplasia, particularly the development of hepatocellular carcinoma. Other neoplasms, such as colorectal tumors, are also associated. Complications related to the treatment of chronic anemia include the appearance of peliosis hepatis and tumors, which can regress after the suspension of treatment with drugs. Knowledge of the disease and of the patterns of iron deposition in patients with iron overload enables not only diagnosis, but also treatment, follow-up, and the detection of possible complications by using imaging methods.

Comparison of complications rates between multiparametric magnetic resonance imaging-transrectal ultrasound (TRUS) fusion and systematic TRUS prostatic biopsies.

PURPOSE: The aim of this study was to compare the complication rates between transrectal ultrasound (TRUS) systematic prostate biopsy and multiparametric magnetic resonance imaging (MRI)-TRUS fusion prostate biopsy techniques. MATERIALS AND METHODS: This is a single-center retrospective study, institutional review board approved. Systematic TRUS and MRI-TRUS fusion prostate biopsy complication rates were compared in 967 men. A total of 319 patients were received systematic TRUS prostate biopsy and 648 patients underwent systematic TRUS + MRI-TRUS fusion prostate biopsy. Complications were divided into immediate (those that occurred during the hospital observation period) and late (those that occurred within 5 days after biopsy). RESULTS: Seventeen complications were observed in patients who received either a systematic prostate biopsy or MRI-TRUS fusion prostate biopsy. Severe complications were not observed in both groups. Among patients who underwent systematic prostate biopsy, 6 (1.9%) cases of complications were observed and between those who received MRI-TRUS fusion prostate biopsy 11 (1.7%) cases of complications after the procedure (p = 0.873) were observed, with no statistical difference between groups. Also, no statistical differences between early and late complication groups (p > 0.999) were observed. CONCLUSIONS: The complication rates were low in both groups, with no critical clinical outcomes and no significant difference of complication rates between systematic TRUS prostate biopsy and MRI-TRUS fusion prostate biopsy techniques.