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Table 2 Main technical aspects and rationale for mpMRI core-sequences

From: Evolution of prostate MRI: from multiparametric standard to less-is-better and different-is better strategies

Sequence Rationale/investigated parameter Technique Role in prostate cancer assessment with mpMRI Limitations
DWI To exploit restricted diffusion of water molecules as a marker of increased cellularity and neoplastic reorganisation of normal glandular tissue • Fat-saturated, free-breathing single-shot spin-echo echo-planar imaging
• At least two b values to generate the ADC map (e.g., minimum 50–100 s/mm2, maximum 800–1000 s/mm2); extrapolated ultra-high b-values (≥ 1400 s/mm2) can also be used to generate the ADC map
• Ultra-high b values can be acquired to increase tumour conspicuity (not for the ADC map generation in less performing systems)
• Field of view 16–22 cm, slice thickness ≤ 4 mm without gap, pixel size ≤ 2.5 mm (phase and frequency), TR ≤ 3000 ms, TE ≤ 90 ms
Detection and localisation:
• dominant sequence for assessing PZ findings
• secondary role in assessing category 3 findings found by T2WI in the TZ
• Sensitive to artefacts from air in the rectum and/or motion
• Distortions
• Relatively unstandardised technique, leading to limited reproducibility of the quantitative analysis of ADC (no definite cut-off values)
• Significant overlap of ADC values between benign conditions and tumours with different aggressiveness
T2WI To provide high-resolution and high-contrast representation of the zonal anatomy of the prostate, as well as of periprostatic anatomy (seminal vesicles, neurovascular bundles, bladder, rectum, and the levator ani) • 2D turbo spin-echo with high spatial resolution: field of view 12–20 cm to cover the prostate and the seminal vesicles; slice thickness ≤ 3 mm with no gap; pixel size ≤ 0.7 mm (phase) x ≤ 0.4 mm (frequency)
• Sagittal, oblique transverse, oblique coronal (posterior prostate wall as anatomic landmark)
• Detection and localisation: dominant sequence for assessing TZ findings
• Locoregional staging: detection of extraprostatic extension or seminal vesicle invasion
• Nonspecific tumour appearance, overlapping with that of non-malignant conditions (e.g., inflammation or post-biopsy changes)
• Sensitive to motion artefacts given the prolonged acquisition time
DCE To detect earlier and more intense contrast enhancement of cancer compared to normal prostatic tissue, as the expression of tumoural neoangiogenesis (denser, poorly formed vessels with increased capillary permeability) • Sequential acquisition of a T1-weighted 2D or 3D gradient-echo sequence with high temporal resolution (≤ 10 s, ideally ≤ 7 s, with TR < 5 ms and TE < 100 ms). Acquisition before, during and after contrast injection (at least 2 min) to detect early enhancement
• Field of view encompassing the whole gland and seminal vesicles
• Slice thickness ≤ 3 mm without gap, and pixel size ≤ 2 mm (phase and frequency)
• If possible fat-saturated or subtracted images
• Oblique transverse plane
• Contrast injection rate 2–3 mL/s
• To upgrade ambiguous findings in the PZ
• See Table 3 for further details
• Variable enhancement pattern of cancer, overlapping with non-malignant conditions (e.g., inflammation or benign prostatic hyperplasia)
• Longer acquisition time (> 2 min) to assess the permeability
  1. 2D two-dimensional, 3D three-dimensional, ADC apparent diffusion coefficient, DCE dynamic contrast-enhanced imaging, DWI diffusion-weighted imaging, mpMRI multiparametric magnetic resonance imaging, PZ peripheral zone, T1WI T1-weighted imaging, T2WI T2-weighted imaging, TE time of echo, TR time of repetition, TZ transition zone