What’s new in Genitourinary Imaging – April 2021

3 weeks ago

 

Original Research

 

Population-Based Prostate Cancer Screening With Magnetic Resonance Imaging or Ultrasonography The IP1-PROSTAGRAM Study

Eldred-Evans D, Burak P, Connor MJ, Day E, Evans M, Fiorentino F, Gammon M, Hosking-Jervis F, Klimowska-Nassar N, McGuire W, Padhani AR, Prevost AT, Price D, Sokhi H, Tam H, Winkler M, Ahmed HU.

JAMA Oncol. 2021 Mar 1;7(3):395-402. doi: 10.1001/jamaoncol.2020.7456. PMID: 33570542; PMCID: PMC7879388.

https://pubmed.ncbi.nlm.nih.gov/33570542/

This is a prospective cohort study conducted across 7 primary care practices and 2 imaging centers in the UK in men age 50-69. Each study subject underwent a screening examination with PSA, biparametric MRI (T2W and DWI), and US (B-mode and Shear wave elastography). The 15-minute MRI examination included T2W and DWI sequences with scores assigned to each case using the Prostate Imaging- Reporting Data System version 2 (PIRADs 2.0). The B-mode US was scored using a validated 5-point scoring system, and shear wave elastography was scored using the World Federation for Ultrasound in Medicine and Biology guidelines. 408 men received all screening exams. The proportion of positive MRI results were greater than positive PSA (Positive MRI and US was a score of 3-5 and Positive PSA is ≥ 3.0 ng/mL). PSA detected 7 clinically significant cancers, while MRI with score of PIRADs 3-5 detected 14 and 4-5 detected 11 cancers. US exams with score of 3-5 detected 9 cancers and 4-5 detected 4 cancers. Clinically insignificant cancers were also detected using PSA in 6 cases, PIRADs 3-5 in 7 cases, PIRADs 4-5 in 5 cases, US score 3-5 in 13 cases, and US score 4-5 in 7 cases. The group suggests that the use of MRI as a screening tool with a PIRADs score of 4 or 5 was associated with more men diagnosed with clinically significant cancer without an increase in the number of men who undergo biopsy with clinically insignificant cancer.

 

Tomoelastography Based on Multifrequency MR Elastography for Prostate Cancer Detection: Comparison with Multiparametric MRI

Li M, Guo J, Hu P, Jiang H, Chen J, Hu J, Asbach P, Sack I, Li W.

Radiology. 2021 Mar 9:201852. doi: 10.1148/radiol.2021201852. Epub ahead of print. PMID: 33687285.

https://pubmed.ncbi.nlm.nih.gov/33687285/

This group compared the sensitivity and specificity of tomoeleastography and multiparametric MRI (mpMRI) for prostate cancer detection. Tomoelastography is an advanced MR elastography technique that uses multiple frequencies and phase encoding directions to determine the mechanical properties of the tissue. They generated the shear-wave speed (c) and phase angle of the shear modulus (φ), which are known surrogate markers of tissue stiffness and fluidity respectively. Their objective was to detect a difference between patients with prostate cancer, benign disease, and healthy controls using tomoelastography. A prospective study with 208 patients (73 had prostate cancer, 82 had benign prostatic disease, and 53 were healthy controls) was completed. The group found a statistically significant difference in c and φ in the prostate cancer group compared to the benign prostatic disease group and healthy controls (p < 0.001 using Kruskal-Wallis test). The mean values were highest in the prostate cancer group. They also found that these parameters combined with mpMRI improved the specificity (95% vs 77% with mpMRI alone) for detection of prostate cancer. The authors conclude that prostate stiffness quantified by tomoelastography improved the diagnostic performance of PIRADs 2.1 in the detection of prostate cancer.

 

Virtual Unenhanced Dual-Energy CT Images Obtained with a Multimaterial Decomposition Algorithm: Diagnostic Value for Renal Mass and Urinary Stone Evaluation

Xiao JM, Hippe DS, Zecevic M, Zamora DA, Cai LM, Toia GV, Chandler AG, Dighe MK, O’Malley RB, Shuman WP, Wang CL, Mileto A.

Radiology. 2021 Mar;298(3):611-619. doi: 10.1148/radiol.2021192448. Epub 2021 Jan 19. PMID: 33464180.

https://pubmed.ncbi.nlm.nih.gov/33464180/

This group assessed virtual unenhanced (VUE) images generated by a multimaterial decomposition algorithm obtained from patients undergoing dual-energy CT (DECT) for renal mass or urinary stone evaluation. 4 radiologists independently evaluated 273 renal masses in 221 patients in this retrospective study. The classification of an enhancing mass or nonenhancing cyst did not change with use of VUE instead of true unenhanced images (TUE), and the average attenuation difference between VUE and TUE was within 3 HU. The performance of stone detection was worse for VUE compared to TUE with reduced sensitivity for stones ≤ 3 mm. The authors concluded that VUE and TUE performed equivalently for renal mass characterization, while the performance of VUE to detect stones ≤ 3 mm was suboptimal compared to TUE.

 

MRI-guided Focused Ultrasound Ablation for Localized Intermediate-Risk Prostate Cancer: Early Results of a Phase II Trial 

Ghai S, Finelli A, Corr K, Chan R, Jokhu S, Li X, McCluskey S, Konukhova A, Hlasny E, van der Kwast TH, Incze PF, Zlotta AR, Hamilton RJ, Haider MA, Kucharczyk W, Perlis N.

Radiology. 2021 Mar;298(3):695-703. doi: 10.1148/radiol.2021202717. Epub 2021 Feb 2. PMID: 33529137.

https://pubmed.ncbi.nlm.nih.gov/33529137/

The group conducted a prospective phase II trial to determine the safety and early outcomes of MR-guided focused ultrasound (MRgFUS) for the treatment of intermediate risk clinically significant prostate cancer. This trial recruited 44 men with unifocal clinically significant prostate cancer that was visible on MRI. No major treatment-related adverse events occurred with 41 of the 44 patients free of prostate cancer at the treatment site on biopsy 5 months post MRgFUS. There was no change in International Prostate Symptom Score (IPSS) and International Index of Erectile Function – 15 (IIEF-15) when comparing baseline with the scores 5 months after treatment in the entire study population. The patients with larger ablations did experience a reduction in the IIEF-5 at 6 weeks (p < 0.01) and 5 months (adjusted p =0.07). The group concludes that MRgFUS is a safe new therapy for localized intermediate risk prostate cancer with promising new outcomes.

Educational Articles

 

Pearls and Pitfalls in Imaging of Pelvic Adnexal Torsion: Seven Tips to Tell It’s Twisted

Strachowski LM, Choi HH, Shum DJ, Horrow MM.

Radiographics. 2021 Mar-Apr;41(2):625-640. doi: 10.1148/rg.2021200122. PMID: 33646910.

https://pubmed.ncbi.nlm.nih.gov/33646910/

This article discusses the definition, epidemiology, and symptoms of adnexal torsion, while appreciating several key imaging findings. The authors also discuss mimics and pitfalls of ovarian torsion. The authors organize their discussion by emphasizing 7 tips on determining the presence of adnexal torsion which includes the following:

  • Clinical signs of nausea and vomiting
  • Ovarian edema
  • Whirlpool sign
  • Strange situs
  • Pain with neoplasm
  • + Doppler does not exclude torsion
  • Twisted tubes

 

Infiltrative Renal Malignancies: Imaging Features, Prognostic Implications, and Mimics

Sweet DE, Ward RD, Wang Y, Tanaka H, Campbell SC, Remer EM.

Radiographics. 2021 Mar-Apr;41(2):487-508. doi: 10.1148/rg.2021200123. Epub 2021 Jan 15. PMID: 33449838.

https://pubmed.ncbi.nlm.nih.gov/33449838/

This article describes imaging features of infiltrative renal neoplasms on cross-sectional imaging and discusses the importance of recognizing an infiltrative pattern in terms of prognosis and treatment. They also identify a variety of benign and malignant renal lesions with an infiltrative pattern and discuss the imaging features, and most importantly, some of the distinguishing features between the various entities.

References
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