SUVmax/ADC Ratio as a Molecular Imaging Biomarker for Diagnosis of Biopsy-Naïve Primary Prostate Cancer

Abstract

Background: Gallium-68-prostate-specific membrane antigen ( 68 Ga-PSMA) positron emission tomography/computed tomography (PET/CT) has recently been shown to be very high accuracy in biopsy-naïve prostate cancer (PCa) detection and can potentially improve the low specificity noted with diffusion-weighted magnetic resonance imaging (DW-MRI), especially in instances of prostate inflammation. We aimed to compare the diagnostic accuracy of DW-MRI and PSMA PET/CT using apparent diffusion coefficient (ADC) and maximum standardized uptake (SUV max ) values in the diagnosis of PCa. Patients and Methods: A retrospective study comparing and analyzing the diagnostic accuracy of prebiopsy DW-MRI and 68 Ga-PSMA PET/CTs done in patients with suspected PCa (raised prostate specific antigen [PSA] and/or positive digital rectal examination) from January 2019 to December 2020. The standard of reference was transrectal ultrasound-guided biopsies. Results: Sixty-seven patients were included in the study, mean age: 70 years (range 49–84), mean PSA: 23.2 ng/ml (range 2.97–45.6). Biopsy was positive for PCa in 56% ( n = 38) and negative in 43% ( n = 29). Of the benign results, benign hyperplasia was noted in 75% ( n = 22) and prostatitis in 25% ( n = 7). Of the PCa, 55% ( n = 21) of were high International Society of Urological Pathology (ISUP) grade (4–5) and 45% ( n = 17) low/intermediate ISUP grade (1–3). Overall the sensitivity/specificity/Accuracy for prediction of PCa of MRI using prostate imaging and reporting data system version 2 criteria and PSMA PET/CT using PCa molecular imaging standardized evaluation criteria was 92.1%/65.5%/80.5% and 76.3%/96.5%/85.1% respectively. Mean apparent diffusion co-efficient (mean ADC) value of benign lesions and PCa was 1.135 × 10 -3 mm 2 /s and 0.723 × 10 -3 mm 2 /s, respectively ( P = 0.00001). Mean SUV max and ADC of benign and PCa lesions was 4.01 and 16.4 ( P = 0.000246). Mean SUV max /ADC ratio of benign and malignant lesions was 3.8 × 103 versus 25.21 × 103 ( P < 0.000026). Inverse correlation was noted between ADC and SUV max values ( R = −0.609), inverse correlation noted between ADC and Gleason's score ( R = −0.198), and positive correlation of SUV max and SUV max /ADC with Gleason's score ( R = 0.438 and R = 0.448). Receiver operating characteris...

The Role of [68Ga]PSMA PET/CT for Clinical Suspicion of Prostate Cancer in Patients with or without Previous Negative Biopsy: A Systematic Review

“…After initial screening according to titles, eligible criteria, and removal of duplicates, a total of 25 articles were selected. Of these, 18 were finally included and downloaded in a full-text version [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. No further studies were added after examination of the references of these articles ( Figure 1 : PRISMA flowchart of the study).…”

“…Two experienced nuclear medicine specialists always interpreted results by consensus. In 8 articles, there was a direct comparison with MRI [ 22 , 23 , 26 , 28 , 31 , 32 , 33 , 35 ]. In 7 of them, MRI scans were acquired on 3.0 Tesla (T) MRI by four sequences: T1-weighted imaging, T2-weighted imaging, fat-suppression presaturation-attenuated inversion recovery, and diffusion-weighted imaging (DWI); PI-RADS v2.0 was used for reporting images in all of them.…”

“…Total prostatectomy or prostate biopsy defining csPCa as Gleason score ≥ 7 or based on the International Society of Urological Pathology (ISUP) grade system represented the standard reference. In particular, 12 out of 18 articles used TRUS-guided biopsy as gold standard [ 22 , 23 , 24 , 25 , 26 , 29 , 31 , 33 , 35 , 36 , 37 , 39 ], 4 PET/TRUS fusion–guided prostate biopsy [ 27 , 30 , 32 , 38 ], and 2 radical prostatectomy specimen [ 28 , 34 ].…”

Evaluation of Three Imaging Methods to Quantify Key Events in Pelvic Bone Metastasis

“…Consequently, malignant lesions tend to exhibit lower ADC values compared to benign lesions, while an increase in ADC is observed in lesions with treatment response [ 20 ]. Previous literature had varied correlation findings between PET and DWI for nonosseous malignancy [ 21 , 22 , 23 , 24 , 25 ]. Neither of the methods is cancer cell-specific and depends on various factors such as tracer metabolism and tissue composition [ 26 ].…”