الفهرس 
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Abstract
SUMMARY & CONCLUSION
The prostate is an exocrine gland composed of both glandular and non-glandular tissue. It is a cone-shaped organ encircling the neck of bladder and urethra with the apex located immediately above the urogenital diaphragm and the broad base below the bladder (Kim B. & Kim C.K, 2013).
Prostate cancer is the most common non cutaneous cancer in elderly men, and the second leading cause of cancer-related death in developed countries. (Zidan S, et al,2015)
Although most types of prostate cancer grow slowly and may need minimal treatment, other types are aggressive and can spread quickly. Prostate cancer that is detected early has a better chance of successful treatment. Therefore, detection of prostate cancer in an early stage is important but remains challenging (Jemal et al. 2012).
Localization of prostate cancer is an important given in the emergence of disease-targeted therapies. Knowledge of the lesion location within the prostate can help to direct maximal therapy to the largest focus of tumor while minimizing damage to the surrounding structures, such as the neurovascular bundles, the rectal wall and the bladder neck (Haider et al , 2007)
By 1990, trans rectal ultrasound (TRUS) has emerged as the best imaging modality of the prostate. Its use led to an improved understanding and demonstration of intra glandular anatomy. For long time, TRUS is used screening, diagnosis and monitoring of benign disease, prostatic cancer and for guiding biopsy from the suspicious lesions (Kammermeir, 1991).
Because of the limitations of these available diagnostic tools, much effort is being put into improving the accuracy of prostate cancer detection. Advances in MRI techniques show potential for improving the diagnostic accuracy of MRI for prostate cancer detection.
Recently, great interest has been shown in multi-parametric MRI, which combines anatomic T2-weighted (T2W) imaging and T1Wwith MR spectroscopic imaging (MRSI), diffusion-weighted imaging (DWI) and/or dynamic contrast-enhanced MRI (DCE-MRI) (Sciarra et al, 2011). T1W images are not used for diagnostic purposes because zonal anatomy is difficult to identify and tumors are typically not well seen. However, T1W images are helpful in determining if there is residual hemorrhage due to prior biopsy (Sankineni et al, 2016)
High-resolution axial T2-TSE is the backbone of every MR image of the prostate. T2W imaging allows precise visualization of the zonal anatomy of the prostate. Moreover, nodular, glandular, stromal, and cystic changes in benign prostate hyperplasia (BPH) can be reliably visualized. Prostate carcinomas can be detected inT2w imaging on the basis of their low-signal, classic oval shape as well as their space occupying nature once they reach a certain size. For T2w imaging without functional sequences, the sensitivity and specificity for prostate cancer are approximately 57 – 83 % and 62 – 82 %. The diagnostic limitations of T2w imaging alone are due to the often similar nature of regularly occurring acute and chronic inflammation of the prostate and hemorrhages, which also cause a hypo intense pattern in T2w imaging. (Durmus et al, 2014).
functional MRI techniques can provide metabolic information, display altered cellularity, and aid in noninvasive characterization of tissue and tumor vascularity (Pinto et al. 2013). Although these techniques have not been implemented broadly in daily clinical practice yet, they are increasingly mentioned in prostate cancer guidelines (Heidenreich et al. 2012). The latest diagnostic consensus statement by the European Society of Urogenital Radiology (ESUR) recommends anatomic T2-weighted imaging combined with at least two functional techniques: diffusion-weighted imaging (DWI), dynamic contrast-enhanced MRI (DCE-MRI), and optionally MR spectroscopy. The accuracy of this method has, however, not been studied systematically (Barentsz ett al. 2014).
MRI is superior in staging of tumors as depicted by its higher sensitivity in eliciting capsular integrity, ECE, SV involvement, LN metastasis and bone marrow infiltration. (Hayat M. 2010)
Aim of our study was to evaluate the diagnostic accuracy of MRI techniques in detection and characterization of different prostatic lesions in comparison with TRUS, and to highlight the value of the advanced MRI techniques in accurate detection, localization and staging of cancer prostate.
In our study, By using TRUS in our study, we found that about 13 cases have enlargement with nodule with percentage of 43.3%) 6 case were histopathologically
proved as malignant lesions and 7 were benign), 13 cases have enlargement without nodule with percentage of 43.3%) 9 case were histopathologically proved as malignant lesions and 4 were benign) and 4 cases have cystic lesion with percentage of 13.3%.
Also, by TRUS Biopsy, 11 case were diagnosed as BPH (also proved histopathologically) with percentage of 36.7% and last 19 were malignant with percentage of 63.3%). This was similar to several previous studies as study from Singapore was performed on 24 men, cancer detection rate of 59.2% (Yuen et al. 2004) and Zangos et al. (2005).
By using conventional MRI almost more than two third of cases 23 (76.7%) had abnormal signal at T2W enlarged transitional zone with abnormal peripheral zone, By MR diffusion there was restriction in 20 (66.7%) cases, only 1 of them were benign , 4 cases were metastatic secondary lesions ) , while 14 cases were adenocarcinoma and 4 case histopathologically proved to be prostate cancer with no restriction (facilitated diffusion).
However, MRI spectroscopy of peripheral zone showed 17 cases were suggesting cancer with percentage of 56.7% (high [(Cho + CR) \ CIT] ratio) , 6 cases were border line and only 7 cases were normal with percentage of 23.3%.
By Contrast enhanced MRI, we found that only 17 cases with percentage of 56.7% have curve suggesting malignancy, 2 cases are negative for malignancy and 11 case have non-specific curve with percentage of 36.7%.
Conclusion:
Currently, the clinical standard for the definitive diagnosis of prostate cancer is trans-rectal ultrasound (TRUS)- biopsy. However, this type of TRUS guided biopsy has a significant sampling error and can miss up to 30% of cancers and may show underestimation of Gleason grade, especially in anteriorly located tumors. it may lead to an increase in complications
MRI has an essential role to play in making safer in diagnosis. It can aid in staging also and surgery or radiation treatment planning.
Although T2W MR imaging has been used widely for diagnosis on the basis of its excellent soft tissue resolution, but its accuracy for the detection and localization of cancer prostate is unsatisfactory as T2-weighted imaging has significant limitations for depicting cancer in the transitional and central zones. In addition, low signal intensity may be seen in the peripheral zone on T2-weighted images in the presence of many non-cancerous abnormal conditions, such as nonspecific inflammation, biopsy related hemorrhage, post-radiation therapy fibrosis, and changes after hormone deprivation therapy
The implementation of multi parametric MRI (mp MRI) into a diagnosis program improve the diagnostic performance
In this study Conventional MRI has moderate sensitivity 81.8% and low specificity 37.3% in diagnosing prostate malignancy.
Using of mpMRI combination of diffusion-weighted, Dynamic contrast enhanced and 3D 1H MR spectroscopic imaging is a promising approach for discriminating between benign and malignant lesions in the PZ and increase sensitivity 100 % and specificity 96.6 % in diagnosing prostate malignancy.
Substantial progress has been made in the imaging of prostate cancer, particularly in MR imaging; these advances are beginning to translate into better treatment selection and more accurate image-guided therapies. In addition, our increased understanding of the early detection of local recurrence is leading to more accurate assessments of patients with increasing PSA levels after therapy. It is hoped that these advances in imaging will contribute to long-term improvements in morbidity from prostate cancer and patients’ quality of life and to a decrease in mortality from prostate cancer that we are now just beginning to see.