PI-RADS is designed to improve focal lesion detection, localization, characterization, and risk stratification in patients with suspected cancer and consists of technical recommendation for MRI acquisition and a scoring system for image interpretation. PI-RADS uses a scale of 1–5 to report the overall probability of clinically significant prostate cancer on multiparametric MRI (mpMRI). The use of PI-RADS is limited to treatment naive patients and it should not be used for staging, assessment of treatment outcome, recurrence, or progression during surveillance.
Prostate imaging reporting and data system (PI-RADS)
The score is assessed on prostate MRI. Images are obtained using a multiparametric technique including T2 weighted images, a dynamic contrast study (DCE), and diffusion-weighted magnetic resonance imaging (DWI).
A score is given according to each variable. The scale is based on a score from 1 to 5 (which is given for each lesion), with 1 being most probably benign and 5 being highly suspicious of malignancy.
Overall PI-RADS score definition
|PI-RADS||Definition||Overall score with T2, DWI, and DCE|
|1||Most probably benign||3-4|
|5||Highly suspicious for malignancy||13-15|
The revised PI-RADS
T2-WI for PZ
- Uniform signal hyperintensity (normal)
- Linear, wedge?shaped, or diffuse mild hypointensity, usually indistinct margin
- Heterogeneous signal intensity or noncircumscribed, rounded, moderate hypointensity
- Circumscribed, homogeneously moderate hypointense focus or mass confined to prostate and <1.5 cm in greatest dimension
- Same as 4 but >/=1.5 cm in greatest dimension or definite extraprostatic extension or invasive behavior
T2-WI for TZ
- Homogeneously intermediate signal intensity (normal)
- Circumscribed hypointense or heterogeneous encapsulated nodule(s) (BPH)
- Heterogeneous signal intensity with obscured margins. Includes others that do not qualify as 2, 4, or 5
- Lenticular or noncircumscribed, homogeneous, moderately hypointense and <1.5 cm in greatest dimension
- Same as 4, but >/= 1.5 cm in greatest dimension or definite extraprostatic extension or invasive behavior
- No abnormality on ADC and DWI with high b-value (>/=1400)
- Indistinct hypointense on ADC maps
- Focal mildly or moderately hypointense on ADC maps and isointense or mildly hyperintense on high b-value DWI (>/=1400)
- Focal markedly hypointense on ADC maps and markedly hyperintense on DWI with high b values (>/=1400) and <1.5 cm on axial images
- Same as 4 but >/=1.5 cm in greatest dimension or definite extraprostatic extension and invasive behavior
- Negative: No early enhancement, diffuse enhancement not corresponding to a focal finding on T2-WI and/or DWI, or focal enhancement corresponding to a lesion showing features of BPH on T2-WI
- Positive: Focal enhancement and enhancement earlier than or contemporaneously with that of adjacent normal prostatic tissues and findings corresponding with findings suspicious for cancer on T2-WI and/or DWI images
DCE is used to decide between PIRADS 3 (no focal or early enhancement) or upgrade to PIRADS 4 (focal and early enhancement present).
DCE: Dynamic contrast-enhanced; MRI: Magnetic resonance imaging; PZ: Peripheral zone; TZ: Transition zone; SI: Signal intensity; DWI: Diffusion-weighted imaging; ADC: Apparent diffusion coefficient; T2-WI: T2-weighted imaging; T1-WI: T1-weighted imaging; BPH: Benign prostatic hyperplasia; PI-RADS: Prostate Imaging Reporting and Data System
- Barrett T, Turkbey B, Choyke PL. PI-RADS version 2: what you need to know. Clin Radiol. 2015 Nov;70(11):1165-76. [Medline]
- Zhang L, Tang M, Chen S, Lei X, Zhang X, Huan Y. A meta-analysis of use of Prostate Imaging Reporting and Data System Version 2 (PI-RADS V2) with multiparametric MR imaging for the detection of prostate cancer. Eur Radiol. 2017 Dec;27(12):5204-5214. [Medline]
- Hassanzadeh E, Glazer DI, Dunne RM, Fennessy FM, Harisinghani MG, Tempany CM. Prostate imaging reporting and data system version 2 (PI-RADS v2): a pictorial review. Abdom Radiol (NY). 2017 Jan;42(1):278-289. [Medline]
Created Nov 29, 2017.