A look into the newly designed PI Rads v2 which promises to be much simpler than its predecessor.

1. PI RADS v2: An Insight
Dr. Suhas Basavaiah
Resident (MD Radio-diagnosis)

2. INTRODUCTION
 At present, multiparametric magnetic resonance imaging (MRI) is the most sensitive and
specific imaging technique for localizing prostate cancer.
 What is PIRADS ?
• PI-RADS (Prostate Imaging Reporting and Data System) refers to a structured reporting scheme
for evaluating the prostate for prostate cancer. It is designed to be used in a pre-therapy patient.
 What is PIRADS v2?
• The original PI-RADS score was annotated, revised and published as the second version, PI-
RADSv2 by a steering committee with the joint efforts of ACR, ESUR, and AdMeTech Foundation.

3. HISTORY
 European Society of Urogenital Radiology (ESUR) drafted guidelines, including a scoring
system, for prostate MRI known as PI-RADS™ version 1 (PI-RADS™ v1) and published in 2012.
 In an effort to make PI-RADS™ standardization more globally acceptable, the American College
of Radiology (ACR), ESUR and the AdMeTech Foundation established a Steering Committee to
build upon, update and improve upon the foundation of PI-RADS™ v, resulting in the
development of PI-RADS™ v2.

4. OBJECTIVES OF PIRADS v2
 PI-RADS™ v2 is designed to improve detection, localization, characterization, and risk
stratification in patients with suspected cancer in treatment naïve prostate glands.
 The overall objective is to improve outcomes for patients
 Establish minimum acceptable technical parameters for prostate mpMRI
 Simplify and standardize the terminology and content of radiology reports
 Facilitate the use of MRI data for targeted biopsy
 Develop assessment categories that summarize levels of suspicion or risk and can beused to
select patients for biopsies and management (e.g., observation strategy vs. immediate
intervention)
 Enable data collection and outcome monitoring
 Educate radiologists on prostate MRI reporting and reduce variability in imaging
interpretations
 Enhance interdisciplinary communications with referring clinicians

5. LIMITATIONS
 PI-RADS™ v2 is not a comprehensive prostate cancer diagnosis document and should be
used in conjunction with other current resources.
 For example, it does not address the use of MRI for detection of suspected recurrent
prostate cancer following therapy, progression during surveillance, or the use of MRIfor
evaluation of other parts of the body (e.g. skeletal system) that may be involved with
prostate cancer.
 Furthermore, it does not elucidate or prescribe optimal technical parameters; only those
that should result in an acceptable mpMRI examination.

6. CLINICAL CONSIDERATIONS
 Timing of MRI
• Hemorrhage after prostate biopsy can present as hyperintensity on T2WI, which can affect
mpMRI assessment and grading. An Interval of at least 6 weeks or longer between biopsy
and MRI should be considered for staging.
 Patient preparation
• To reduce motion artifact from bowel peristalsis - use an antispasmodic agent
• minimal preparation enema administered to the patient in the hours prior to the exam may
be beneficial
• patient should be in the prone position or suction should be used to remove air and
decompress rectum.
 Patient information
• PSA levels, date and results of biopsy, Gleason score, other clinical history, medications,
surgeries and family history.

7. TECHNICAL SPECIFICATIONS
 T2W, DWI, and DCE should be included in all exams.
 Prostate MRI acquisition protocols should always be tailored to specific patients, clinical
questions, management options, and MRI equipment.
 at least one pulse sequence should use a field-of-view (FOV) that permits evaluation of
pelvic lymph nodes to the level of the aortic bifurcation.
 1.5 T IS GOOD BUT 3T IS BEST
 The recommendations focus only on 3T and 1.5T MRI scanners
 Prostate mpMRI at lower magnetic field strengths (<1.5T) is not recommended.

8. TECHNICAL SPECIFICATIONS (CONTD.)
 Endo rectal Coil (ERC)
• may be particularly valuable for high spatial resolution imaging used in cancer staging
and for inherently lower SNR sequences, such as DWI and high temporal resolution
DCE.
• Credible satisfactory results have been obtained at both 1.5T and 3T without the use of
an ERC.
• Fluid inflated ERC have better imaging quality compared to air inflated but are not
100% artefact free.

9. Normal Anatomy
 From superior to inferior, the prostate consists of the base (just below the urinary
bladder), the midgland, and the apex.
 It is divided into four histologic zones:
(a) the anterior fibromuscular stroma, contains no glandular tissue;
(b) the transition zone (TZ), surrounding the urethra proximal to the verumontanum,
contains 5% of the glandular tissue;
(c) the central zone (CZ), surrounding the ejaculatory ducts, contains about 20% of the
glandular tissue; and
(d) the outer peripheral zone (PZ), contains 70%-80% of the glandular tissue.
 When benign prostatic hyperplasia (BPH) develops, the TZ will account for an increasing
percentage of the gland volume.

10. PIRADS anatomic division
 The segmentation model used in PI-RADS™ v2
employs thirty-nine sectors/regions:
• thirty-six for the prostate,
• two for the seminal vesicles and
• one for the external urethral sphincter.
 (PZ) at prostate base, midgland, and apex are each
subdivided into three sections: anterior (a), medial
posterior (mp), and lateral posterior (lp).
 (TZ) at prostate base, midgland, and apex are each
subdivided into two sections: anterior (a) and
posterior (p).
 The central zone (CZ) is included in the prostate
base around the ejaculatory ducts.
 The anterior fibromuscular stroma (AS) is divided
into right/left at the prostate base, midgland, and
apex.

11.  Approximately 70%-75% of prostate cancers originate in the PZ and 20%-30% in the TZ.
 cancers that occur in the CZ are usually secondary to invasion by PZ tumors.
 Based on location and differences in signal intensity on T2W images, the TZ can often be
distinguished from the CZ on MR images
 In some patients, age-related expansion of the TZ by BPH may result in compression and
displacement of the CZ .

12. Mid Gland Apex

13. BENIGN FINDINGS
 Benign prostatic hyperplasia (BPH)
• Benign prostatic hyperplasia (BPH) develops in response to testosterone, after it is
converted to di-hydrotestosterone.
• BPH arises in the TZ, although exophytic and extruded BPH nodules can be found in the PZ.
• It consists of mixture of stromal and glandular hyperplasia and may appear as band-like
areas and/or encapsulated round nodules with circumscribed margins.
• Predominantly glandular BPH nodules and cystic atrophy exhibit moderate-marked T2
hyperintensity and are distinguished from malignant tumors by their signal and capsule.
• Predominantly stromal nodules exhibit T2 hypointensity.
• BPH nodules may be highly vascular on DCE
• although BPH is a benign entity, it may have important clinical implications for biopsy
approach and therapy since it can increase gland volume, stretch the urethra.

15. PIRADS – ASSESMENT
 The score is assessed on prostate MRI. Images - T2 weighted images, a dynamic contrast
study (DCE) and DWI. If DCE or DWI are insufficient for interpretation, the newest
guidelines recommend omitting them in the scoring.
 Currently, MR spectroscopy is not included in PI-RADS scoring.
 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:
 PI-RADS 1: very low (clinically significant cancer is highly unlikely to be present)
 PI-RADS 2: low (clinically significant cancer is unlikely to be present)
 PI-RADS 3: intermediate (the presence of clinically significant cancer is equivocal)
 PI-RADS 4: high (clinically significant cancer is likely to be present)
 PI-RADS 5: very high (clinically significant cancer is highly likely to be present)

16. T2-weighted imaging

19. Transition Zone

22. Diffusion weighted imaging (DWI)

26. Dynamic contrast enhancement (DCE)
 negative: no early enhancement, or diffuse enhancement not corresponding to
a focal finding on T2 and/or DWI or focal enhancement corresponding to a
lesion demonstrating features of BPH on T2
 positive: focal, and earlier than or contemporaneously with enhancement of
adjacent normal prostatic tissues, and corresponds to suspicious finding on T2
and/or DWI

32. PIRADS v2 SCORING

35. Conclusion
 a consistent instruction on how to calculate the overall PI-RADS score is lacking.
 Since these guidelines were published, several research groups validated the PI-RADS score
and most of them calculated a PI-RADS sum score (scale from 3 to 15) by summation of the 3
single scores [16, 19–24].
 Another method to assign a final PI-RADS score is not to use the sum score of all different
parameters, but rather overall interpretation score, identical to the BI-RADS system. This
means that the final score will not be in the range of 3–15, but in the range of 1–5.
 Baur et al. (2014) after evaluation of the current PI-RADS system, they concluded that
assigning a DWI score for peripheral zone lesions and a T2WI score for transition zone lesions
was sufficient for stratification of patients for further diagnostic workup.

36. Conclusion (contd.)
 Thompson et al. (Thompson et al. 2014) evaluated PIRADS scoring in a population of 150
men with no prior mpMRI that were referred for biopsy due to rising PSA and suspicious
findings of the digital rectal exam. 48/150 patients underwent radical prostatectomy.
 The study concluded that PIRADS exhibited excellent NPV, and moderate PPV for
significant PCa.
 Roethke et al.(2014) investigated the performance of PIRADS prospectively in a
population of 64 consecutive patients that were referred for MR/US fusion biopsy due to
suspicion of Pca. The study found out that there is significant variability in sensitivity and
specificity lesion detection by PIRADS category grades. (73%/92% and 85%/67% for PI-
RADS scores of 9 and 10, respectively; 85%/56% and 60%/97% for Likert scores of 3
and 4, respectively).
 In conclusion, the PI-RADS classification is still work in progress and will have further
improvement in the future. Furthermore, more studies have to be done to validate the
accuracy and interobserver variability.

37. Thank You
Thank You