Correlation between metabolite ratios and ADC values of prostate in men with increased PSA level

Kumar, Virendra; Jagannathan, Naranamangalam R.; Kumar, Rajeev; Das, Sharat C.; Jindal, Lokesh; Thulkar, Sanjay; Gupta, Siddhartha D.; Dwivedi, Sadanand N.; Roell, Stefan; Hemal, Ashok K.; Gupta, Narmada P.

doi:10.1016/j.mri.2006.01.001

« Previous Next »Magnetic Resonance Imaging
Volume 24, Issue 5 , Pages 541-548, June 2006

Correlation between metabolite ratios and ADC values of prostate in men with increased PSA level

Virendra Kumar
- Department of NMR, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Naranamangalam R. Jagannathan
- Department of NMR, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
- Corresponding author. Tel.: +91 11 2659 3253, 2658 8533; fax: +91 011 2658 8663, 2658 8641.
Rajeev Kumar
- Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Sharat C. Das
- Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Lokesh Jindal
- Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Sanjay Thulkar
- Department of Radio-diagnosis, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Siddhartha D. Gupta
- Department of Pathology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Sadanand N. Dwivedi
- Department of Biostatistics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Stefan Roell
- Siemens AG, Medical Solutions MR, Application Development Spectroscopy (MREA-MRS), 91050 Erlangen, Germany
Ashok K. Hemal
- Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
Narmada P. Gupta
- Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India

Received 29 October 2005; accepted 10 January 2006. published online 07 March 2006.

Abstract

Proton magnetic resonance spectroscopic imaging (MRSI) and diffusion-weighted imaging (DWI) were carried out in men with increased prostate-specific antigen (PSA) level. Forty subjects [controls (Group I) and patients (Groups II and III with PSA >20 and 4–20 ng/ml, respectively)] were investigated using endorectal coil at 1.5 T prior to transrectal ultrasound (TRUS)-guided biopsy. Metabolite ratio [citrate/(choline+creatine)] and apparent diffusion coefficient (ADC) were calculated for identical voxels. In patients, voxels that showed lower metabolite ratio showed reduced ADC in the peripheral zone (PZ) of the prostate, and voxels with increased metabolite ratio showed higher ADC. Metabolite ratios were used to predict areas of malignancy if the ratio was <1.4 and if ADC value was <1.17×10⁻³ mm²/s. Patients in Group II had lower metabolite ratio and ADC in the PZ compared to controls and Group III. All 13 were positive for malignancy in MR, while 12 of 13 were positive on TRUS-guided sextant biopsy. In Group III, certain voxels of PZ that showed reduced metabolite ratio also showed lower ADC. A positive correlation was observed between metabolite ratio and ADC. MR predicted areas of malignancy in PZ in 15 of 20 patients; however, only six were positive on TRUS-guided biopsy perhaps due to high false-negative rate of TRUS-guided biopsy. Results show positive correlation between MRSI and DWI and their potential in detection of malignancy, thereby improving the diagnosis especially in patients with PSA level of 4–20 ng/ml.

Keywords: Magnetic resonance spectroscopic imaging (MRSI), Diffusion-weighted imaging (DWI), Prostate-specific antigen (PSA), Prostate cancer, Apparent diffusion coefficient (ADC), Citrate/(Cho+Cr) ratio