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European Radiology

, Volume 27, Issue 7, pp 2776–2783 | Cite as

PI-RADS version 2: quantitative analysis aids reliable interpretation of diffusion-weighted imaging for prostate cancer

  • Sung Yoon Park
  • Su-Jin Shin
  • Dae Chul Jung
  • Nam Hoon Cho
  • Young Deuk Choi
  • Koon Ho Rha
  • Sung Joon Hong
  • Young Taik Oh
Urogenital

Abstract

Objectives

To determine whether apparent diffusion coefficient (ADC) ratio aids reliable interpretation of diffusion-weighted imaging (DWI) for prostate cancer (PCa).

Methods

Seventy-six consecutive patients with PCa who underwent DWI and surgery were included. Based on pathologic tumour location, two readers independently performed DWI scoring according to the revised Prostate Imaging Reporting and Data System (PI-RADSv2). ADC ratios of benign to cancerous prostatic tissue were then measured independently and compared between cases showing concordant and discordant DWI scores ≥4. Area under the curve (AUC) and threshold of ADC ratio were analyzed for DWI scores ≥4.

Results

The rate of inter-reader disagreement for DWI score ≥4 was 11.8% (9/76). ADC ratios were higher in concordant vs. discordant DWI scores ≥4 (median, 1.7 vs. 1.1–1.2; p < 0.001). For DWI scores ≥4, the AUCs of ADC ratios were 0.970 for reader 1 and 0.959 for reader 2. In patients with an ADC ratio >1.3, the rate of inter-reader disagreement for DWI score ≥4 decreased to 5.9–6.0%. An ADC ratio >1.3 yielded 100% (reader 1, 54/54; reader 2, 51/51) positive predictive value for clinically significant cancer.

Conclusion

ADC ratios may be useful for reliable interpretation of DWI score ≥4 in PI-RADSv2.

Key points

The ADC ratio correlated positively with DWI score of PI-RADSv2.

ADC ratio >1.3 was associated with concordant interpretation of DWI score4.

ADC ratio >1.3 was associated with high PPV for clinically significant cancer.

ADC ratio is useful for reliable interpretation of DWI scoring in PI-RADSv2.

Keywords

PI-RADS Diffusion-weighted imaging Apparent diffusion coefficient MRI Prostate cancer 

Abbreviations

ADC

Apparent diffusion coefficient

PI-RADSv2

Prostate Imaging Reporting and Data System version 2

DWI

Diffusion-weighted imaging

DCE

Dynamic contrast-enhanced

MR

Magnetic resonance

TR

Repetition time

TE

Echo time

PCa

Prostate cancer

CSC

Clinically significant cancer

PZ

Peripheral zone

TZ

Transition zone

ECE

Extracapsular extension

SVI

Seminal vesicle invasion

ROI

Region of interest

ROC

Receiver operating-characteristic

AUC

Area under the curve

PPV

Positive predictive value

CI

confidence interval

PSA

Prostate-specific antigen

GS

Gleason score

Notes

Acknowledgements

The scientific guarantor of this publication is Young Taik Oh. The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article. The authors state that this work has not received any funding. No complex statistical methods were necessary for this paper. Institutional Review Board approval was obtained. Written informed consent was waived by the Institutional Review Board. Methodology: retrospective, cross sectional study, performed at one institution.

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Copyright information

© European Society of Radiology 2016

Authors and Affiliations

  • Sung Yoon Park
    • 1
  • Su-Jin Shin
    • 2
    • 3
  • Dae Chul Jung
    • 1
  • Nam Hoon Cho
    • 2
  • Young Deuk Choi
    • 4
  • Koon Ho Rha
    • 4
  • Sung Joon Hong
    • 4
  • Young Taik Oh
    • 1
  1. 1.Department of Radiology and Research Institute of Radiological Science, Severance HospitalYonsei University College of MedicineSeoulRepublic of Korea
  2. 2.Department of PathologyYonsei University College of MedicineSeoulSouth Korea
  3. 3.Department of PathologyHanyang University College of MedicineSeoulSouth Korea
  4. 4.Department of UrologyYonsei University College of MedicineSeoulSouth Korea

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