What’s new in Genitourinary Imaging – August 2020

2 years ago
Evaluating Biochemically Recurrent Prostate Cancer: Histologic Validation of 18F-DCFPyL PET/CT with Comparison to Multiparametric MRI

Lindenberg L, Mena E, Turkbey B, et al. Evaluating Biochemically Recurrent Prostate Cancer: Histologic Validation of 18F-DCFPyL PET/CT with Comparison to Multiparametric MRI [published online ahead of print, 2020 Jul 7]. Radiology. 2020;192018. doi:10.1148/radiol.2020192018

https://doi.org/10.1148/radiol.2020192018

In this prospective study by Lindenburg et al, the authors sought to histologically validate the use of 2-(3-{1-carboxy-5-[(6-[18F]fluoro-pyridine 3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (18FDCFPyL) PSMA PET tracer agent to detect prostate cancer recurrence in patients with rising PSA levels and compare those results to multiparametric MRI (mpMRI). 18FDCFPyL is a fluorine labeled PSMA PET agent that has shown high affinity for prostate malignancies while demonstrating promise in the identification of metastatic disease or residual prostate cancer.  323 lesions were detected by 18FDCFPyL and mpMRI in 77 men with biochemical recurrence after prostatectomy and/or radiation therapy. 18FDCFPyL performed better in pelvic lymph node detection than mpMRI (128 vs 23 nodes) with a detection concordance of 25% (82 of 323). Histologic evaluation of 80 lesions demonstrated sensitivity, specificity, and PPV for the detection of prostate cancer of 69%, 91%, and 86% for 18F-DCFPyL and 69%, 74%, and 69% for mpMRI. The authors show that 18F-DCFPyL in conjunction with mpMRI improves the PPV for the detection of histopathologically confirmed prostate cancer by 38%.

 

Percutaneous CT- and MRI-guided Cryoablation of cT1 Renal Cell Carcinoma: Intermediate- to Long-term Outcomes in 307 Patients

Bhagavatula SK, Tuncali K, Shyn PB, Levesque VM, Chang SL, Silverman SG. Percutaneous CT- and MRI-guided Cryoablation of cT1 Renal Cell Carcinoma: Intermediate- to Long-term Outcomes in 307 Patients [published online ahead of print, 2020 Jul 7]. Radiology. 2020;200149. doi:10.1148/radiol.2020200149

https://doi.org/10.1148/radiol.2020200149

This is a single center retrospective study conducted by Bhagavatula et al. to evaluate intermediate and long-term outcomes of 307 patients with cT1 renal cell carcinoma (RCC) who have had treatment with CT or MRI guided cryoablation. The sparsity of current literature and the heterogeneous designs of various studies regarding long term outcomes of cryotherapy for the treatment of cT1 RCC have led the authors to perform survival outcomes on patients who have had image-guided cryotherapy for cT1 lesions in their own institution. They evaluated overall survival (91%, 86%, 78%, and 76%), disease free survival (94%, 91%, 88%, and 88%), local progression free survival (97%, 95%, 95%, 95%), and disease specific survival ( 99.6%, 99%, 99%, and 99%) at 3, 5, 10, and 15 years respectively. They showed no significant difference in survival between CT and MRI guided cryotherapy with both percutaneous methods showing similar excellent survival outcomes.

 

Bosniak Classification Version 2019 of Cystic Renal Masses Assessed with MRI

Tse JR, Shen J, Yoon L, Kamaya A. Bosniak Classification Version 2019 of Cystic Renal Masses Assessed With MRI [published online ahead of print, 2020 Jun 9]. AJR Am J Roentgenol. 2020;1-7. doi:10.2214/AJR.19.22740

http://doi.org/10.2214/AJR.19.22740

Tse et al. performed a single center retrospective study using multiphase MRI to evaluate 59 renal cysts with both the 2019 and original versions of the Bosniak criteria and compared the assigned category to the pathologic results. Two abdominal radiologists evaluated the lesions independently and by consensus with an inter-reader agreement of Kappa of 0.57 for the original version and 0.55 for the 2019v. The results of the study showed that the overall sensitivity and specificity of identifying renal cell carcinoma (RCC) was 100% and 86% with the 2019v and 95% and 81% with original Bosniak criteria. The results showed that the 2019 version of the Bosniak criteria is more sensitive and specific for the evaluation of renal cystic lesions with MRI.

 

MRI of the Prostate With and Without Endorectal Coil at 3T: Correlation With Whole-Mount Histopathologic Gleason Score

Dhatt R, Choy S, Co SJ, et al. MRI of the Prostate With and Without Endorectal Coil at 3 T: Correlation With Whole-Mount Histopathologic Gleason Score. AJR Am J Roentgenol. 2020;215(1):133-141. doi:10.2214/AJR.19.22094

http://doi.org/10.2214/AJR.19.22094

Dhatt et al. performed a single center prospective study involving 23 patients with biopsy-proven prostate cancer who underwent multiparametric MRI (mpMRI) with and without an endorectal coil (ERC). The patients underwent 3T mpMRI with and without an ERC during the same visit. The images were evaluated by two radiologists independently who determined no significant difference in image quality between images acquired with an ERC and those acquired without based on a 5-point system (with ERC 3.8 vs without ERC 3.5). The AUC for detection of clinically significant cancer (Gleason score equal or greater than 7) for individual readers was 0.96 and 0.96 with ERC and 0.88 and 0.91 without ERC.  4 of 13 tumors with Gleason score 3+4 were undetected without the ERC, while 1 of 5 tumors with Gleason score less than 3+4 was undetected both with and without ERC. The group concluded that the mpMRI with or without ERC had comparable accuracy for Gleason score 3+4 or greater tumors, while mpMRI with ERC was superior at lesion detection.

 

Assessment of Split Renal Function Using a Combination of Contrast-Enhanced CT and Serum Creatinine Values for Glomerular Filtration Rate Estimation

Shi W, Liang X, Wu N, Zhang H, Yuan X, Tan Y. Assessment of Split Renal Function Using a Combination of Contrast-Enhanced CT and Serum Creatinine Values for Glomerular Filtration Rate Estimation. AJR Am J Roentgenol. 2020;215(1):142-147. doi:10.2214/AJR.19.22125

http://doi.org/10.2214/AJR.19.22125

Shi et al. performed a single center retrospective study of 62 patients with asymmetric renal disease with the intent to develop a method to estimate single-kidney glomerular filtration rate (GFR) by using contrast-enhanced CT and serum creatinine values. The eGFR of each separate kidney was calculated using a proportionality factor derived from the product of renal volume and CT number increments determined from multiphase CT (non-contrast, arterial, venous, and nephrographic phase). These single-kidney eGFRs generated from each phase were compared to Gates GFR calculated from renal dynamic imaging with 99mTc-diethylenetriamine pentaacetic acid. The authors then calculated correlation coefficients of the non-contrast (0.729), arterial (0.781), venous (0.788), and nephrographic (0.842) phases, which showed that the nephrographic phase correlates best with the smallest maximum deviation of ±36.9% from the Gates GFR. They conclude that the nephrographic phase correlates best to Gates GFR because the renal enhancement is most representative of renal filtration, while arterial and venous phase enhancement is representative of renal perfusion.

 

Diagnostic Performance of MRI in the Detection of Renal Lipid-Poor Angiomyolipomas: A Systematic Review and Meta-Analysis

Wilson MP, Patel D, Murad MH, McInnes MDF, Katlariwala P, Low G. Diagnostic Performance of MRI in the Detection of Renal Lipid-Poor Angiomyolipomas: A Systematic Review and Meta-Analysis [published online ahead of print, 2020 Jun 30]. Radiology. 2020;192070. doi:10.1148/radiol.2020192070

https://doi.org/10.1148/radiol.2020192070

The authors performed a systematic review to determine the diagnostic performance of MRI in the identification of lipid-poor angiomyolipomas (lpAMLs). Articles with more than 10 patients undergoing diagnostic evaluation with MRI with proven histopathologic findings consistent with lpAML were included in the study. 2196 patients were evaluated from 23 studies. The pooled sensitivity, specificity, and AUC were 83%, 90%, and 0.93 respectively. The authors show that MRI is promising for the detection of lpAML and serves as a potential replacement for biopsy.

 

A prospective study of novel mathematical analysis of the contrast-enhanced computed tomography vs renal scintigraphy in renal function evaluation

Fiev D, Proskura A, Khokhlachev S, et al. A prospective study of novel mathematical analysis of the contrast-enhanced computed tomography vs renal scintigraphy in renal function evaluation [published online ahead of print, 2020 Jul 8]. Eur J Radiol. 2020;130:109169. doi:10.1016/j.ejrad.2020.109169

https://doi.org/10.1016/j.ejrad.2020.109169

In this prospective study, the authors developed a mathematical analysis of CT 3D models (MACT) using multiphase CT in order to calculate single kidney renal function. The group prospectively recruited 97 patients and used their MACT model, which is based on the radiologic density of the contrast agent at a certain time point. These calculations of GFR were compared to dynamic renal scintigraphy. Renal function calculated from CT and scintigraphy results were found to be similar with a correlation coefficient of 0.945 (p < 0.001), suggesting that this is a feasible and efficacious method to estimate renal function.

 

Advanced diffusion weighted imaging of the prostate: Comparison of readout-segmented multi-shot, parallel-transmit and single-shot echo-planar imaging

Klingebiel M, Ullrich T, Quentin M, et al. Advanced diffusion weighted imaging of the prostate: Comparison of readout-segmented multi-shot, parallel-transmit and single-shot echo-planar imaging [published online ahead of print, 2020 Jul 2]. Eur J Radiol. 2020;130:109161. doi:10.1016/j.ejrad.2020.109161

https://doi.org/10.1016/j.ejrad.2020.109161

Klingebiel et al. sought to evaluate new approaches to DWI for the detection of prostate cancer. Two blinded readers studied images of 36 patients with biopsy proven prostate cancer, comparing DWI sequences obtained by single-shot echo planar imaging (ss-EPI), parallel transmit EPI (ptx-EPI), and read-out segmented multi-shot EPI (rs-EPI), all acquired during a single exam. DWI sequences were obtained with the following b-values: 0, 500, 1000, and 1500. Ss-EPI showed higher SNR for b1000 and b1500 images, while CNR was higher on rs-EPI in high b-value images. The maximum magnitude of ADC reduction for biopsy proven prostate cancer was on rs-EPI. Although the ss-EPI provides the best SNR, the rs-EPI and ptx-EPI performed better regarding contrast intensity. Rs-EPI performed the best on a subjective 5-point scale.

 

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