Objective: This study aims for targeted biopsy validation of magnetic resonance fingerprinting (MRF) and diffusion mapping for characterizing peripheral zone (PZ) prostate cancer and noncancers. Materials and Methods: One hundred four PZ lesions in 85 patients who underwent magnetic resonance imaging were retrospectively analyzed with apparent diffusion coefficient (ADC) mapping, MRF, and targeted biopsy (cognitive or in-gantry). A radiologist blinded to pathology drew regions of interest on targeted lesions and visually normal peripheral zone on MRF and ADC maps. Mean T1, T2, and ADC were analyzed using linear mixed models. Generalized estimating equations logistic regression analyses were used to evaluate T1 and T2 relaxometry combined with ADC in differentiating pathologic groups. Results: Targeted biopsy revealed 63 cancers (low-grade cancer/Gleason score 6 = 10, clinically significant cancer/Gleason score ≥7 = 53), 15 prostatitis, and 26 negative biopsies. Prostate cancer T1, T2, and ADC (mean ± SD, 1660 ± 270 milliseconds, 56 ± 20 milliseconds, 0.70 Â 10 −3 ± 0.24 Â 10 −3 mm 2 /s) were significantly lower than prostatitis (mean ± SD, 1730 ± 350 milliseconds, 77 ± 36 milliseconds, 1.00 Â 10 −3 ± 0.30 Â 10 −3 mm 2 /s) and negative biopsies (mean ± SD, 1810 ± 250 milliseconds, 71 ± 37 milliseconds, 1.00 Â 10 −3 ± 0.33 Â 10 −3 mm 2 /s). For cancer versus prostatitis, ADC was sensitive and T2 specific with comparable area under curve (AUC; (AUC T2 = 0.71, AUC ADC = 0.79, difference between AUCs not significant P = 0.37). T1 + ADC (AUC T1 + ADC = 0.83) provided the best separation between cancer and negative biopsies. Low-grade cancer T2 and ADC (mean ± SD, 75 ± 29 milliseconds, 0.96 Â 10 −3 ± 0.34 Â 10 −3 mm 2 /s) were significantly higher than clinically significant cancers (mean ± SD, 52 ± 16 milliseconds, 0.65 ± 0.18 Â 10 −3 mm 2 /s), and T2 + ADC (AUC T2 + ADC = 0.91) provided the best separation. Conclusions: T1 and T2 relaxometry combined with ADC mapping may be useful for quantitative characterization of prostate cancer grades and differentiating cancer from noncancers for PZ lesions seen on T2-weighted images.

We found that a bp-MRI examination can detect clinically significant lesions and changed patient management in 10.8% of the patients. A rapid MRI protocol can be used as a useful secondary screening tool in men presenting with suspicion of prostate cancer.

Background Cardiac MR fingerprinting (cMRF) is a novel technique for simultaneous T1 and T2 mapping. Purpose To compare T1/T2 measurements, repeatability, and map quality between cMRF and standard mapping techniques in healthy subjects. Study Type Prospective. Population In all, 58 subjects (ages 18–60). Field Strength/Sequence cMRF, modified Look–Locker inversion recovery (MOLLI), and T2‐prepared balanced steady‐state free precession (bSSFP) at 1.5T. Assessment T1/T2 values were measured in 16 myocardial segments at apical, medial, and basal slice positions. Test–retest and intrareader repeatability were assessed for the medial slice. cMRF and conventional mapping sequences were compared using ordinal and two alternative forced choice (2AFC) ratings. Statistical Tests Paired t‐tests, Bland–Altman analyses, intraclass correlation coefficient (ICC), linear regression, one‐way analysis of variance (ANOVA), and binomial tests. Results Average T1 measurements were: basal 1007.4±96.5 msec (cMRF), 990.0±45.3 msec (MOLLI); medial 995.0±101.7 msec (cMRF), 995.6±59.7 msec (MOLLI); apical 1006.6±111.2 msec (cMRF); and 981.6±87.6 msec (MOLLI). Average T2 measurements were: basal 40.9±7.0 msec (cMRF), 46.1±3.5 msec (bSSFP); medial 41.0±6.4 msec (cMRF), 47.4±4.1 msec (bSSFP); apical 43.5±6.7 msec (cMRF), 48.0±4.0 msec (bSSFP). A statistically significant bias (cMRF T1 larger than MOLLI T1) was observed in basal (17.4 msec) and apical (25.0 msec) slices. For T2, a statistically significant bias (cMRF lower than bSSFP) was observed for basal (–5.2 msec), medial (–6.3 msec), and apical (–4.5 msec) slices. Precision was lower for cMRF—the average of the standard deviation measured within each slice was 102 msec for cMRF vs. 61 msec for MOLLI T1, and 6.4 msec for cMRF vs. 4.0 msec for bSSFP T2. cMRF and conventional techniques had similar test–retest repeatability as quantified by ICC (0.87 cMRF vs. 0.84 MOLLI for T1; 0.85 cMRF vs. 0.85 bSSFP for T2). In the ordinal image quality comparison, cMRF maps scored higher than conventional sequences for both T1 (all five features) and T2 (four features). Data Conclusion This work reports on myocardial T1/T2 measurements in healthy subjects using cMRF and standard mapping sequences. cMRF had slightly lower precision, similar test–retest and intrareader repeatability, and higher scores for map quality. Evidence Level 2 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2020;52:1044–1052.

We describe multi-institutional experience using free-breathing, 3D Spiral GRAPPA-based quantitative perfusion MRI in characterizing neoplastic liver masses. 45 patients (age: 48–72 years) were prospectively recruited at University Hospitals, Cleveland, USA on a 3 Tesla (T) MRI, and at Zhongshan Hospital, Shanghai, China on a 1.5 T MRI. Contrast-enhanced volumetric T1-weighted images were acquired and a dual-input single-compartment model used to derive arterial fraction (AF), distribution volume (DV) and mean transit time (MTT) for the lesions and normal parenchyma. The measurements were compared using two-tailed Student’s t-test, with Bonferroni correction applied for multiple-comparison testing. 28 hepatocellular carcinoma (HCC) and 17 metastatic lesions were evaluated. No significant difference was noted in perfusion parameters of normal liver parenchyma and neoplastic masses at two centers (p = 0.62 for AF, 0.015 for DV, 0.42 for MTT for HCC, p = 0.13 for AF, 0.97 for DV, 0.78 for MTT for metastases). There was statistically significant difference in AF, DV, and MTT of metastases and AF and DV of HCC compared to normal liver parenchyma (p < 0.5/9 = 0.0055). A statistically significant difference was noted in the MTT of metastases compared to hepatocellular carcinoma (p < 0.001*10-5). In conclusion, 3D Spiral-GRAPPA enabled quantitative free-breathing perfusion MRI exam provides robust perfusion parameters.

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