False positive and false negative diagnoses of prostate cancer at multi-parametric prostate MRI in active surveillance.

Jeffrey S. Quon,Maneesh Khanna,Trevor A. Flood,Christopher S. Lim,Nicola Schieda,Bardia Moosavi

doi:10.1007/s13244-015-0411-3

Jeffrey S. Quon, Maneesh Khanna + Show 4 more

Open Access

https://doi.org/10.1007/s13244-015-0411-3

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Abstract

MP-MRI is a critical component in active surveillance (AS) of prostate cancer (PCa) because of a high negative predictive value for clinically significant tumours. This review illustrates pitfalls of MP-MRI and how to recognise and avoid them. The anterior fibromuscular stroma and central zone are low signal on T2W-MRI/apparent diffusion coefficient (ADC), resembling PCa. Location, progressive enhancement and low signal on b ≥1000 mm²/s echo-planar images (EPI) are differentiating features. BPH can mimic PCa. Glandular BPH shows increased T2W/ADC signal, cystic change and progressive enhancement; however, stromal BPH resembles transition zone (TZ) PCa. A rounded morphology, low T2 signal capsule and posterior/superior location favour stromal BPH. Acute/chronic prostatitis mimics PCa at MP-MRI, with differentiation mainly on clinical grounds. Visual analysis of diffusion-weighted MRI must include EPI and appropriate windowing of ADC. Quantitative ADC analysis is limited by lack of standardization; the ADC ratio and ADC histogram analysis are alternatives to mean values. DCE lacks standardisation and has limited utility in the TZ, where T2W/DWI are favoured. Targeted TRUS-guided biopsies of MR-detected lesions are challenging. Lesions detected on MP-MRI may not be perfectly targeted with TRUS and this must be considered when faced with a suspicious lesion on MP-MRI and a negative targeted TRUS biopsy histopathological result.Keypoints• Multi-parametric MRI plays a critical role in prostate cancer active surveillance.• Low T2W signal intensity structures appear dark on ADC, potentially simulating cancer.• Stromal BPH mimics cancer at DWI and DCE.• Long b value trace EPI should be reviewed• Targeted biopsy of MR-detected lesions using TRUS guidance may be challenging.

Highlights

Prostate cancer (PCa) is the most common cancer among males in North America [1, 2] and the most common solid neoplasm in Europe [3]
Glandular benign prostatic hyperplasia (BPH) is readily differentiated from transition zone (TZ) PCa at MP-MRI [35] and typical features include a wellcircumscribed, sharply demarcated and rounded shape, a continuous low T2W signal intensity (SI) rim, increased T2W SI often with cystic change, low SI on long≥1000 mm2/s b value echo-planar images (EPI), BT2 shine-through^ on apparent diffusion coefficient (ADC) maps and benign/progressive/type I contrast kinetics with a low transfer constant on DCE (Fig. 6) [25, 35]
Regardless of the method used, due to differences across systems, at present, we suggest that the use of quantitative ADC in clinical practice should be applied carefully, derived and validated on an institutional basis

Summary

Introduction

Prostate cancer (PCa) is the most common cancer among males in North America [1, 2] and the most common solid neoplasm in Europe [3]. Certain areas of the prostate gland [i.e., the anterior gland, transition zone (TZ) and apex] are known to be under-sampled or not sampled at all at routine nontargeted TRUS-guided biopsy and are increasingly being recognised as areas that may contain clinically significant (CS) tumours [13]. These limitations are of critical importance in AS, where treatment decisions are based on risk stratification and dependent on accurate Gleason grading of tumours [4]. Echo train Flip angle Acceler-ation Receiver Acquisition Number of plane view (mm) gap (mm) length factor bandwidth time (min) signals (Hz/voxel) averaged

Coronal Sagittal Axial Axial

Findings

Conclusion