What’s new in Genitourinary Imaging – June 2021

3 years ago


Original Research 


Pharmacokinetic modeling of dynamic contrast-enhanced (DCE)-MRI in PI-RADS category 3 peripheral zone lesions: preliminary study evaluating DCE-MRI as an imaging biomarker for detection of clinically significant prostate cancers 

Abreu-Gomez J, Lim C, Cron GO, Krishna S, Sadoughi N, Schieda N.  

Abdom Radiol (NY). 2021 Apr 5. doi: 10.1007/s00261-021-03035-6. Epub ahead of print. PMID: 33818626. 


In this retrospective study, the objective was to use pharmacokinetic modeling of dynamic contrast enhanced Magnetic Resonance Imaging (DCE-MRI) for the diagnosis of peripheral zone  PIRADS 3 v2.1 prostate cancer (clinically significant prostate cancer (CS-PCa), ISUP grade group ≥ 2) in men with subjectively negative DCE-MRI. The group retrospectively evaluated 73 men across two institutions with PIRADS 3 lesions, who subsequently had targeted biopsy yielding 12 CS-PCas, 27 clinically insignificant prostate cancers (ISUP grade group 1), and 34 benign lesions. They showed a statistically significant difference in the mean influx volume transfer (Ktrans) and fractional extracellular fluid space volume (Ve) with the area under the curve (AUC) of 0.69 for the diagnosis of CS-PCa for both parameters. The mean Ktrans and Ve were higher in patients with CS-PCa compared to ISUP 1 and benign lesions. Of note, the group did not show a significant difference in comparing the mean and 10th percentile ADC between CS-PCa, ISUP 1, and benign lesions. The authors conclude that pharmacokinetic parameters are useful in differentiating CS-PCa and outperforms ADC. 

Diagnostic Accuracy and Interobserver Agreement of PI-RADS Version 2 and Version 2.1 for the Detection of Transition Zone Prostate Cancers 

Wei CG, Zhang YY, Pan P, Chen T, Yu HC, Dai GC, Tu J, Yang S, Zhao WL, Shen JK. 

AJR Am J Roentgenol. 2021 May;216(5):1247-1256. doi: 10.2214/AJR.20.23883. Epub 2021 Feb 24. PMID: 32755220. 


The objective of this retrospective study was to compare the interobserver agreement and accuracy of PI-RADS 2.0 and 2.1 for the detection of clinically significant prostate cancer (csPCa) in the transition zone (TZ) among 5 radiologists with varying degrees of clinical experience. 355 patients with TZ lesions underwent biopsy with 34 ISUP grade group 1, 59 ISUP grade group ≥ 2, and 262 noncancerous lesions. Interobserver agreement was higher for PIRADS 2.1 vs 2.0 with higher pooled AUC for the detection prostate cancer (PCa) (0.866 v 0.827) vs CS-PCa (0.929 v 0.899). The pooled sensitivity, specificity, and accuracy were also higher: 

  • TZ PCa (sensitivity, specificity, and accuracy) 
  • v2.1 – 86.9%, 79.4%, and 75.4% 
  • v2.0 – 79.4%, 71.8%, and 73.8% 
  • TZ CS-PCa (sensitivity, specificity, and accuracy) 
  • v2.1 – 84.8%, 90.9%, and 89.9% 
  • v2.0 – 81.4%, 89.9%, and 88.5% 

The authors also found that the reader with the least experience had the lowest sensitivity, specificity, and accuracy, while the reader with the most experience has the highest sensitivity, specificity, and accuracy. The authors concluded that PI-RADS 2.1 had better interobserver agreement and diagnostic accuracy compared to PI-RADS 2.0, however reader experience continues to impact diagnostic performance of PI-RADS 2.1. 


Pelvic floor imaging with MR defecography: correlation with gynecologic pelvic organ prolapse quantification 

Swamy N, Bajaj G, Olliphant SS, Henry JA, Jambhekar K, Pandey T, Ram R.  

Abdom Radiol (NY). 2021 Apr;46(4):1381-1389. doi: 10.1007/s00261-020-02476-9. PMID: 32211947. 


This article was originally published in the March 2020 issue and is again presented in Abdominal Radiology 2021 in the special section highlighting pelvic floor imaging. The authors conducted a retrospective, single institution study comparing the grading of pelvic organ prolapse (POP) clinically by physical exam and radiologically by MR defecography (MRD). The clinical grading was completed by physical exam by two urogynecologist and the MRD was evaluated by a fellowship trained radiologist who also graded the POP based on MRI. They evaluated 68 patients, who underwent both MRD and POP quantification (POP-Q), and found that MRI has a strong, moderate, and weak correlation for POP quantification of the anterior, middle, and posterior compartment prolapse respectively. The authors conclude that anterior and middle compartment prolapse identified by MRD have better correlation to POP-Q. The authors attributed these findings to the inherent differences existing in the MRI technique and anatomic landmarks between the two methods. The authors suggest that both methods of staging will result in the best patient care. 


The feasibility of a radial turbo-spin-echo T2 mapping for preoperative prediction of the histological grade and lymphovascular space invasion of cervical squamous cell carcinoma 

Li S, Zhang Z, Liu J, Zhang F, Yang M, Lu H, Zhang Y, Han F, Cheng J, Zhu J. 

Eur J Radiol. 2021 Apr 1;139:109684. doi: 10.1016/j.ejrad.2021.109684. Epub ahead of print. PMID: 33836336. 


The objective of this study was to compare radial turbo-spin-echo (TSE) T2 mapping and diffusion weighted imaging (DWI) to differentiate histologic grades and lymphovascular space invasion (LVSI) of cervical squamous cell carcinoma (CSCC).  The group evaluated 58 patients with CSCC and compared them to 40 healthy volunteers. There was a statistically significant difference in the T2 and ADC values between the healthy volunteers and patients with CSCC. Poorly differentiated tumors (G3) had lower T2 and ADC values compared to the moderately (G2) and well (G1) differentiated tumors. The AUC for T2 and ADC to differentiate G1/G2 from G3 was 0.74 for T2 mapping and 0.76 using ADC values. T2 values performed superiorly to ADC in patients with evidence of LVSI with AUC of 0.887 (ADC values had an AUC of 0.537). There was a statistically significant difference in the T2 values of patients with and without LVSI, while no statistically significant difference was present for ADC values. The authors concluded that Radial TSE T2 mapping can serve as a non-invasive biomarker for histologic grade and evidence of LVSI in patients with CSCC. 

VI-RADS: Multiinstitutional Multireader Diagnostic Accuracy and Interobserver Agreement Study 

Ueno Y, Tamada T, Takeuchi M, Sofue K, Takahashi S, Kamishima Y, Urase Y, Kido A, Hinata N, Harada K, Fujisawa M, Miyaji Y, Murakami T.

AJR Am J Roentgenol. 2021 May;216(5):1257-1266. doi: 10.2214/AJR.20.23604. Epub 2020 Jul 29. PMID: 32755215. 


The objective of this retrospective study was to evaluate the interobserver agreement and performance of Vesicle Imaging Reporting and Data System (VI-RADS) in 91 patients with bladder tumors. After a training session, 5 experienced and 2 inexperienced radiologists used VI-RADS to score bladder tumors. 48 patients had muscle invasive bladder cancer (MIBC), while 43 had non-muscle invasive bladder cancer (NMIBC). There was moderate to substantial agreement between the experienced readers and substantial agreement between the inexperienced readers. The pooled sensitivity and specificity for the following are listed: 

  •  VI-RADS score of ≥ 4 was 74.1% and 94.1% and 63.9% and 86.4% for experienced and inexperienced readers respectively 
  • VI-RADS score of  ≥ 3 was 83.4% and 77.3% and 82.0% and 73.9% for experienced and inexperienced readers respectively 

Pooled AUC to evaluate the diagnostic performance of VI-RADS is as follows: 

  • 0.88 for experienced readers 
  • 0.84 for inexperienced readers 
  • 0.87 for all readers 

In conclusion the authors observed a pooled AUC of 0.87 for all readers with moderate to substantial interobserver agreement. 

Combining volumetric apparent diffusion coefficient histogram analysis with vesical imaging reporting and data system to predict the muscle invasion of bladder cancer

Li S, Liang P, Wang Y, Feng C, Shen Y, Hu X, Hu D, Meng X, Li Z.

Abdom Radiol (NY). 2021 Apr 28. doi: 10.1007/s00261-021-03091-y. Epub ahead of print. PMID: 33909091. 


The objective of this retrospective study was to determine if muscle invasive bladder cancer (MIBC) could be better differentiated from non-muscle invasive bladder cancer (NMIBC) by using volumetric ADC histogram analysis in addition to VI-RADS. The authors reviewed 80 patients with pathologically proven NMIBC (n=53) and MIBC (n=27) and compared ADC histogram parameters (min ADC, mean ADC, median ADC, max ADC, 10th, 25th, 75th, 90th percentile ADC, skewness , kurtosis, and entropy) and VI-RADS scores. Mann-Whitney U-test revealed a statistically significant difference in the ADC histogram parameters between MIBC and NMIBC except for the ADC max and the entropy. VI-RADS had an AUC of 0.88 with a sensitivity 88.89% and specificity 83.61%. The combination VI-RADS and skewness showed the highest AUC of 0.92. The authors concluded that volumetric ADC histogram analysis and VI-RADS are both valuable methods, and that ADC histogram analysis can provide value to VI-RADS in the differentiation of MIBC and NMIBC.   


Role of tadalafil in enhancing visualization of posterior urethra prior to combined voiding cystourethrogram and retrograde urethrogram: a retrospective analysis 

Fahmy A, Elgebaly O, Elsawy MM, Orabi S.  

Abdom Radiol (NY). 2021 May 13. doi: 10.1007/s00261-021-03109-5. Epub ahead of print. PMID: 33983471. 


This retrospective study evaluates the usefulness of tadalafil in the visualization of the posterior urethra during voiding cystourethrogram (VCUG) and retrograde urethrogram (RUG) in patients with urethral strictures due to pelvic fracture urethral distraction defect, bulbar stricture with complete obliteration, and post catheterization. The group evaluated 60 men undergoing combined VCUG and RUG with half of the subjects receiving a single 20 mg dose of tadalafil 2 hours before the procedure, while the other half were in the control group. 90% in the tadalafil group and 40% in the control group (p < 0.05) were successful in opening bladder outlet on initiation of voiding. There were no serious adverse events with few patients experiencing mild adverse events. The authors conclude that tadalafil is safe, and effectively relaxes the bladder neck and posterior urethra in patients undergoing combined VCUG and RUG for the evaluation of urethral strictures. 

Urinary involvement in Erdheim–Chester disease: computed tomography imaging findings 

Wu Z, Jiang GL, Tang Y, Jiang C, Sun LL, Li N, Jin ZY, Sun H.  

Abdom Radiol (NY). 2021 May 10. doi: 10.1007/s00261-021-03106-8. Epub ahead of print. PMID: 33970298. 


In this retrospective study, the authors describe the urological manifestations of Erdheim-Chester disease (ECD) in 24 patients that presented to Peking Medical College. The authors found that the most common manifestation noted in 70.8% of patient was perirenal infiltration (“hairy kidney”) followed by renal sinus infiltration (66.7%), proximal ureter involvement (58.3%), renal artery sheath (41.7%), hydronephrosis (58.3%), and adrenal glands involvement (33.3%). Histiocytic infiltration was frequently bilateral. The authors conclude that kidneys are the most common organs affected by ECD, and that imaging can be advantageous with early diagnosis as well as designing a treatment regime. 

Educational Articles 


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

Schieda N, Davenport MS, Krishna S, Edney EA, Pedrosa I, Hindman N, Baroni RH, Curci NE, Shinagare A, Silverman SG.  

Radiographics. 2021 May-Jun;41(3):814-828. doi: 10.1148/rg.2021200160. Epub 2021 Apr 16. PMID: 33861647. 


This article instructs how to use the CT and MRI features for the classification of cystic renal masses using the 2019 version of the Bosniak criteria. The article provides representative pictorial examples, practical tips, and a decision tree to help in effective application of the Bosniak criteria.  

Update on the Role of Imaging in Clinical Staging and Restaging of Renal Cell Carcinoma Based on the AJCC 8th Edition, From the AJR Special Series on Cancer Staging 

Elkassem AA, Allen BC, Sharbidre KG, Rais-Bahrami S, Smith AD.  

AJR Am J Roentgenol. 2021 Mar 24. doi: 10.2214/AJR.21.25493. Epub ahead of print. PMID: 33759558. 


This article reviews the role of cross-sectional imaging (CT and MRI) in the staging and restaging of renal cell carcinoma. The authors discuss the TNM staging categories, which includes tumor size, renal sinus fat invasion, urinary collecting system invasion, perinephric fat invasion, venous invasion, adrenal gland invasion, invasion of the peri-renal fascia, invasion of adjacent organs, and presence of pathologic nodes or distant metastases. Findings related to response to treatment with anti-angiogenic therapy and immunotherapy is also discussed. 

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