The role of T2-weighted imaging in detecting prostate cancer of the central zone in 3T multiparametric magnetic resonance examination

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1 The role of T2-weighted imaging in detecting prostate cancer of the central zone in 3T multiparametric magnetic resonance examination Poster No.: C-2317 Congress: ECR 2014 Type: Scientific Exhibit Authors: V. Forte, V. Panebianco, F. Barchetti, M. Bernieri, E. L. Indino, C. Catalano; Rome/IT Keywords: DOI: Genital / Reproductive system male, MR-Diffusion/Perfusion, Diagnostic procedure /ecr2014/C-2317 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 7

2 Aims and objectives The prostate cancer of the central zone is a "challenge within a challenge" for Radiologists. In fact, under normal conditions, a neoplastic lesion of the peripheral zone may be particularly difficult to assess due to a variety of morphological and functional modifications that occur in the gland's structure during senescence. As regards prostate cancer of the central zone, these events are even more pronounced thanks to changes that take place both in the central and in the transition zone [1, 2, 3, 4]. In patients older than 50 years, the transition zone is increasingly affected by nodular changes from benign prostatic hyperplasia (BPH), which complicate the detection of prostate cancer [5]. BPH nodules show different signal behaviors depending on the size of the epithelial and stromal components. While the epithelial component shows a hyperintense and the stromal component a hypointense signal behavior, combinations of both changes also can be assessed. The BPH nodules are characterized by septation of the individual nodules, which can be seen as a hypointense rim on thet2w images [6]. Due to their infiltrating growth, aggressive prostate cancers in the central glandular zone spread across the septal structures, which is referred to as "charcoal sign" [5]. Larger cancers of the central glandular zone also have a space-occupying component as a sign of malignancy. Aggressive cancers tend to have a more hypointense signal intensity with increasing Gleason score (# 7) [7]. In this context, T2-weighted imaging stands out and play an important role in assessing the neoplastic disease and, therefore, the aim of our study was to validate the role of T2-weighted imaging as dominant sequence in detecting prostate cancer (PC) of the central zone (CZ) in a 3T Multiparametric Magnetic Resonance (Mp-MRI) examination. Methods and materials From a heterogeneous group of 200 patients with altered PSA values and histological proved prostate cancer (PC), we selected 57 patients with histological proved prostate cancer of the central zone (CZ) who underwent a 3T Mp-MRI examination from January 2010 to Janaury 2013: data were retrospectively analysed. Imaging protocol included: a morphological study with high-resolution T2-weighted sequences, a dynamic study with T1-weighted GRE sequences (DCE) acquired after intravenous administration of contrast medium and a diffusion-weighted (DWI) study with exponential b-values (0, 500, 1000, 3000). Two Radiologists evaluated each patient independently. Results Page 2 of 7

3 T2-weighted images showed 100% sensitivity, 99% specificity, 97% accuracy in detecting PC of the CZ; DCE displayed 96% sensitivity, 93% specificity, 92% accuracy; DWI with b-value 3000 s/mm2 displayed 98% sensitivity, 97% specificity, 93% accuracy, while with b-value 1000 s/mm2 91% sensitivity, 89% specificity, 88% accuracy. No statistically significant differences were observed between the two readers (K = 0.985, P = 0.796).Notwithstanding that the percentages shown are high, differences between one and another sequences often can actually help to define better (or worse) a particular finding, during cases evaluation. This concept is well represented by the displayed images (Fig. 1, Fig 2,) that compare sequences' (T2-weighted imaging, DWI, DCE, ADC maps) outcomes in identifying the central zone cancer. T2-weighted imaging offers the most valuable informations while the results obtained by other techniques are erratic. Images for this section: Fig. 1: Graphical representation of how, despite high percentages overall, T2-weighted imaging was the prevailing sequence in statistical evaluation of radiological findings. Page 3 of 7

4 Fig. 2: 59 y.o. patient with PSA value of 20 ng/ml who underwent 3 TRUS guided prostate biopsies with negative outcomes. (A) Using T2 weighted sequences, MRI shows a focal mass localized in the central zone (CZ) that assumes the appearance of a "erased charcoal drawing" sign; two other lesions are spotted on the left portion of the peripheral zone (PZ). (B) DWI technique correctly identifies the peripheral lesions but vastly underestimates the central one. (C) DCE technique highlights a feeble contrast gain in the central lesion, skipping the other ones on the PZ. (4) ADC maps correctly identify both lesions. Page 4 of 7

5 Fig. 3: 63 y.o. patient with PSA value of 5,4 ng/ml who underwent a single negative TRUS guided biopsy. (A)On T2 weighted images, a single hypo intense nodule can been seen on the central zone right portion. (B)DWI technique is not sufficient to characterize the mass because the lesion itself fails to stand out markedly in the context adenoma's parenchyma, showing a hyper intense signal equal to other areas. (C) Perfusion imaging shows that the lesion's contrast enhancement is similar to the one possessed by the adenoma. (4) ADC maps depict cancer's location, matching the morphological outcomes. Page 5 of 7

6 Conclusion Based on our results, we have seen that overall Multiparametric MRI is essential to assess prostate cancer. This statement is even more meaningful if cancer that develops in the central zone has to be assessed. High-resolution T2-weighted imaging can be considered the most reliable technique in detecting PC of CZ. Prostate gland in the course of life undergoes many changes that can deeply modify its micro and macro architecture. Acute and chronic prostatitis, biopsies, a progressive prostatic hypertrophy are all factors that make a suspected tumor difficult to assess, especially if in the central zone. In a context so rich in nuances in which even small things can make a difference, is important to obtain a minimum benchmark to assess radiological findings. In our experience, T2 -weighted imaging can play this key role ; this does not mean that other techniques should be underestimated, because the focus of the word " multiparametric " is the possibility to study a disease through several aspects. This way an assessment can be built as much as possible authentic and relevant to reality (presence or absence of tumor, differential diagnosis with other diseases). To do this it was necessary to clarify what is, among the sequences offered by MRI, the inherently superior method that could be a referring point for a correct analysis of radiological findings. Personal information References [1]Oto A, Kayhan A, Jiang Y et al. Prostate cancer: differentiation of central gland cancer from benign prostatic hyperplasia by using diffusion-weighted and dynamic contrastenhanced MR imaging. Radiology 2010; 257: DOI:radiol [2] Sato C, Naganawa S, Nakamura T et al. Differentiation of noncancerous tissue and cancer lesions by apparent diffusion coefficient values in transition and peripheral zones of the prostate. J Magn Reson Imaging 2005; 21: DOI: /jmri [3] Hoeks CM, Hambrock T, Yakar D, Hulsbergen-van de Kaa CA, Feuth T, Witjes JA, Fütterer JJ, Barentsz JO. Transition zone prostate cancer: detection and localization Page 6 of 7

7 with 3-T multiparametric MR imaging. Radiology Jan;266(1): doi: / radiol Epub 2012 Nov 9. [4] Hoeks CM, Vos EK, Bomers JG, Barentsz JO, Hulsbergen-van de Kaa CA, Scheenen TW. Diffusion-weighted magnetic resonance imaging in the prostate transition zone: histopathological validation using magnetic resonance-guided biopsy specimens. Invest Radiol Oct;48(10): [5]Akin O, Sala E, Moskowitz CS et al.transition zone prostate cancers: features, detection, localization, and staging at endorectal MR imaging. Radiology 2006; 239: DOI: [6]Janus C, Lippert M. Benign prostatic hyperplasia: appearance on magnetic resonance imaging. Urology 1992; 40: [7]Wang L, Mazaheri Y, Zhang J et al. Assessment of biologic aggressiveness of prostate cancer: correlation of MR signal intensity with Gleason grade after radical prostatectomy. Radiology 2008; Page 7 of 7