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ORIGINAL ARTICLE
Year : 2005  |  Volume : 21  |  Issue : 2  |  Page : 106-108
 

Evaluation of endorectal magnetic resonance imaging and magnetic resonance spectroscopic imaging in diagnosing and staging prostate cancer - a prospective pilot study.


P. D. Hinduja National Hospital and Medical Research Center, Mumbai, India

Correspondence Address:
M Dholakia
A/7, Sahayog society,baroda, Gujarat,Baroda 390016
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-1591.19631

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   Abstract 

Aims: The main objective of our study was to evaluate the efficacy of End. MRI and MRSI in (1) detecting and (2) staging prostate cancer by correlating it with histopathological results. Methods: In a double blind prospective study of 20 patients were divided into two groups. In group A with 10 patients, the inclusion criteria were elevated PSA and/or a palpable nodule. All 10 patients with undiagnosed prostate cancer underwent End. MRI and MRSI followed by TRUS guided ten quadrant biopsy. In group B, 10 patients with already proven carcinoma prostate were included. All these patients underwent End. MRI and MRSI followed by radical prostatectomy. Results: The mean S.PSA was 19.8 ng/ml (1.9-52) and the mean Gleason score was 6.8 (5-8). In group A End. MRI/MRSI revealed a diagnosis of prostate cancer in 10 patients, but only six were positive on biopsy. In group B, End. MRI/MRSI showed eight patients to have periprostatic extension but only three were confirmed on final histology. Out of the eight patients that showed periprostatic spread on End. MRI/MRSI, seven patients showed seminal vesicle invasion, and one patient showed capsular infiltration. But on histopathology study seminal vesicle involvement was confirmed in only one patient and only two patients had capsular infiltration. Conclusions: This pilot study reveals that End.MRI/MRSI, although a relatively well-established investigation in the west, has not shown the same degree of accuracy in our setup.


Keywords: Magnetic resonance; Prostate cancer; Spectroscopic imaging


How to cite this article:
Dholakia M, Patil N, Shetty P, Khandkar A, Srinivas V. Evaluation of endorectal magnetic resonance imaging and magnetic resonance spectroscopic imaging in diagnosing and staging prostate cancer - a prospective pilot study. Indian J Urol 2005;21:106-8

How to cite this URL:
Dholakia M, Patil N, Shetty P, Khandkar A, Srinivas V. Evaluation of endorectal magnetic resonance imaging and magnetic resonance spectroscopic imaging in diagnosing and staging prostate cancer - a prospective pilot study. Indian J Urol [serial online] 2005 [cited 2019 Nov 22];21:106-8. Available from: http://www.indianjurol.com/text.asp?2005/21/2/106/19631



   Introduction Top


Prostate cancer is the most common malignancy diagnosed in males and this increase has been attributed to widespread PSA testing. However, not every person with a raised PSA has prostate cancer and an accurate diagnosis without resorting to biopsies is still not possible. Various investigations such as endorectal magnetic resonance imaging (End. MRI), magnetic resonance spectroscopic imaging (MRSI) are being evaluated to determine if they can bridge the gap. The local extent of the disease is important in selecting the appropriate treatment and is an area where End. MRI and MRSI may also play a role. The main objective of our study was to evaluate the efficacy of End. MRI and MRSI in (1) detecting and (2) staging prostate cancer by correlating it with histopathological results.


   Materials and methods Top


A double blind prospective study of 20 patients was carried out at P. D. Hinduja National Hospital, Mumbai, between June 2003 and December 2003. The patients were divided into two groups. In group A with 10 patients, the inclusion criteria was elevated PSA and/or a palpable nodule. All 10 patients with undiagnosed prostate cancer underwent End. MRI and MRSI followed by TRUS guided ten quadrant biopsy.[1] Additionally, biopsy was taken from any suspicious lesion detected on End MRI. Two pathologists reviewed histological slides for presence or absence of prostate cancer.

In group B, 10 patients with already proven carcinoma prostate were included. All these patients underwent End. MRI and MRSI followed by radical prostatectomy.

The time duration between biopsy and MRI was a minimum of 3 weeks and the patients were subjected to surgery within 10 days of End. MRI. All histopathological specimens were sent fresh and axial sections were obtained at intervals of 3-4 mm.

All patients underwent End. MRI and MRSI procedure on 1-5 T whole body magnetic resonance scanner, combined with endorectal, and pelvic phased array coils for evaluating the prostate and to look for pelvic lymph node involvement. The whole procedure takes about 70 min and for the purpose of this study the investigation was free. It normally costs Rs. 9000. T1 and T2 weighted images were obtained on oblique, axial, coronal, and sagittal planes. The metabolic peaks relevant to prostate MRSI are choline, creatine, and citrate. Ratio of choline and creatine to citrate of 0.80 was regarded as normal. Any value of more than 0.80 was regarded abnormal. The radiological findings of End. MRI and the concentration values of MRSI were incorporated by the radiologists in their final conclusions.

Figure showing MR spectral trace obtained from normal peripheral zone of prostatic tissue and from prostate cancer tissue.


   Results Top


The mean age of the patients was 62.3 years (52-76 years). The mean S.PSA was 19.8 ng/ml (1.9-52) and the mean Gleason score was 6.8 (5-8).

In group A End. MRI/MRSI revealed a diagnosis of prostate cancer in 10 patients, but only six were positive on biopsy [Table - 1].

In group B, End. MRI/MRSI showed eight patients to have periprostatic extension but only three were confirmed on final histology [Table - 2].[4]

Out of the eight patients that showed periprostatic spread on End. MRI/MRSI, seven patients showed seminal vesicle invasion, and one patient showed capsular infiltration. But on histopathology study seminal vesicle involvement was confirmed in only one patient and only two patients had capsular infiltration. All the other patients had localized prostate cancer [Figure - 1].

In our study, none of the patients had a regular abdominal MRI so we cannot comment on the relationship of surface MRI to End. MRI.


   Discussion Top


Noninvasive techniques of diagnosing prostate cancer in patients with raised PSA are urgently required as they will reduce the complications associated with biopsy and help in alleviating patient anxiety.[1] The accuracy of End. MRI/MRSI in our study for diagnosing prostate cancer was only 40% compared to western literature where Toricelli et al.[2] showed an accuracy of 90% [Table - 3].

On End. MRI, prostate cancer is characterised by low T2 signal intensity, which is of low significance. The End. MRI has limited sensitivity for prostate cancer because certain tumors are isointense and has limited specificity because of haemorrhage, prostatitis, and hormone therapy. Enthusiasm for the use of this technique, however, has been limited as a result of significant interobserver variability, as evidenced by the wide range of diagnostic accuracies (54-90%) that have been reported in the Western literature.[5] For the management of early prostate cancer, the local extent of disease is important in determining the appropriate treatment modality. In this context, MRI allows a detailed evaluation of prostatic, periprostatic, and pelvic anatomy. Neither TRUS nor computerized tomography (CT scan) can offer this simultaneous coverage.

The MRSI is a method that demonstrates normal or altered tissue metabolism, and therefore, is fundamentally different from other imaging modalities such as TRUS that assess only abnormalities of structure.

In our study accuracy of End. MRI in staging prostate cancer was only 40% [Table - 4].

Improved reproducibility and diagnostic accuracy are required before End. MRI/MRSI can become a widely used local staging modality. Problems that have been found to contribute to the high variability in diagnostic accuracy include a steep learning curve for interpretation of End. MRI/MRSI images and lack of standard diagnostic criteria.[1],[7]

The End. MRI/MRSI also showed poor results in detecting seminal vesicle invasion with accuracy of less than 50% in our study. Thus, our study showed high variability in comparison to other Western studies, which can be attributed to the small number of patients included in our study and due to the learning curve of the radiologists in interpreting End. MRI/MRSI results.

This pilot study reveals that End.MRI/MRSI, although a relatively well-established investigation in the west, has not shown the same degree of accuracy in our setup. Since this is an expensive and time consuming investigation, prospective studies from other centers will be helpful in accumulating data to better determine its exact role in the management of prostate cancer in our country.

 
   References Top

1.Fergus V, Aliya A and Kurhanewicz J. Magnetic resonance Imaging And Spectroscopic imaging Of Prostate Cancer. Journal of Urology: 2003;170:69-76.  Back to cited text no. 1    
2.Torricelli P, Iadanza M, De Santis M, Pollastri CA, Cesinaro AM, Trentini G et al. Magnetic resonance with endorectal coil in the local staging of prostatic carcinoma. Comparison with histologic microsections in 40 cases. Radiol Med (Torino) 1999;97:491-8.  Back to cited text no. 2    
3.Bartolozzi C, Menchi I, Lencioni R, Serni S et al: Local staging of prostate carcinoma with endorectal coil MRI: correlation with whole-mount radical prostatectomy specimens. Eur Radiol 1996;6:339-45.  Back to cited text no. 3    
4.Ogura K, Maekawa S, Okubo K. Dynamic endorectal magnetic resonance imaging for local staging & detection of neurovacular bundle involvement of prostate cancer. Correlating with histopathological results. Urology 2001;57:721-6.  Back to cited text no. 4    
5.Yu K. K., Scheidler J, Hircak H, Vigneron DB, Zaloudek CJ, Males RG et al. Prostate cancer: Prediction of extracapsular extension with endorectal MR imaging and three dimensional proton MR spectroscopic imaging. Radiology 1999;213:481-8.  Back to cited text no. 5    
6.Anthony V, D'Amico, Mitchell S, Richard W. Endorectal coil magnetic resonance imaging identifies locally advance prostate cancer in select patients with clinically localised disease. Urology 1998;51:449-54.  Back to cited text no. 6    
7.Krebs TL, Silverman JM. Clinical utility of endorectal surface coil magnetic resonance imaging for local staging of prostate cancer. J Urol 1993;150:391-5.  Back to cited text no. 7    


    Figures

  [Figure - 1]
 
 
    Tables

  [Table - 1], [Table - 2], [Table - 3], [Table - 4]



 

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    Abstract
    Introduction
    Materials and me...
    Results
    Discussion
    References
    Article Figures
    Article Tables

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