Rotating frame relaxation imaging of prostate cancer: Repeatability, cancer detection, and Gleason score prediction.
OBJECTIVE
To investigate relaxation along a fictitious field (RAFF) and continuous wave (cw) T1ρ imaging of prostate cancer (PCa) in the terms of repeatability, PCa detection, and characterization.


METHODS
Thirty-six patients (PSA 11.6 ± 7.6 ng/mL, mean ± standard deviation) with histologically confirmed PCa underwent two repeated 3T MR examinations using surface array coils before prostatectomy. Relaxation along fictitious field, cw T1ρ, and T2 relaxation times (TRAFF, T1ρcw, T2) were measured and averaged over regions of interest placed in PCa, normal peripheral zone (PZ), and normal central gland (CG) positioned using whole-mount prostatectomy sections and anatomical T2-weighted images. Receiver operating characteristic curve analysis with area under the curve (AUC) was calculated to distinguish PCa from PZ/CG and PCa with Gleason score (GS) of 3+3 from GS of 3+4/≥ 3+4.


RESULTS
TRAFF and T1ρcw relaxation times were repeatable with coefficients of repeatability as a percentage of median value in the range of 7.8-23.2%. AUC (mean, 95% confidence interval) in the differentiation of PCa with GS of 3+3 from PCa with CS of ≥ 3+4 were 0.88 (0.72-0.99), 0.69 (0.46-0.90), and 0.68 (0.45-0.88), for TRAFF, T1ρcw, and T2, respectively.


CONCLUSIONS
In quantitative region of interest based analysis, TRAFF outperformed T1ρcw and T2 in PCa detection and characterization.
Department of Diagnostic Radiology, University of Turku, Turku, Finland.
Ivan
I
Jambor
Department of Diagnostic Radiology, University of Turku, Turku, Finland.
Marko
M
Pesola
Department of Pathology, University of Turku and Turku University Hospital, Turku, Finland.
Pekka
P
Taimen
Department of Information Technology, University of Turku, Turku, Finland.|Turku PET Centre, University of Turku, Turku, Finland.
Harri
H
Merisaari
Department of Surgery, Division of Urology, Turku University Hospital, Turku, Finland.
Peter J
PJ
Boström
Department of Oncology and Radiotherapy, Turku University Hospital, Turku, Finland.
Heikki
H
Minn
Department of Biotechnology and Molecular Medicine, A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland.
Timo
T
Liimatainen
Department of Diagnostic Radiology, University of Turku, Turku, Finland.|Medical Imaging Centre of Southwest Finland, Turku University Hospital, Turku, Finland.
Hannu J
HJ
Aronen
D000328:Adult; D000368:Aged; D000465:Algorithms; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011471:Prostatic Neoplasms / Q000473:pathology*; D015203:Reproducibility of Results; D012399:Rotation; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted
Gleason score; prostate cancer; repeatability; rotating frame relaxation