Multiparametric-magnetic resonance imaging mp-MRI has shown promising results in diagnosis, ppm Prostata- risk stratification and staging of clinically significant prostate cancer. It has also opened up opportunities for focal treatment of prostate cancer. Combinations of T2-weighted imaging, diffusion imaging, perfusion dynamic contrast-enhanced imaging and spectroscopic imaging have been used in mp-MRI assessment of prostate cancer, but T2 morphologic assessment and functional assessment ppm Prostata- diffusion imaging remains the mainstay for prostate cancer diagnosis on mp-MRI.
Because assessment on mp-MRI can be subjective, use of the newly developed standardized reporting Prostate Imaging and Reporting Ppm Prostata- Data System scoring system and education of specialist radiologists are essential for accurate interpretation. This review focuses on the present status of mp-MRI in prostate cancer and its evolving role in the management of prostate cancer. Currently, the diagnostic pathway for prostate cancer detection is initiated on prostate-specific antigen PSA level and digital rectal exam DRE.
Use of PSA as a screening tool followed by systematic transrectal ultrasound-guided TRUS biopsy has resulted in increased detection of prostate cancer with stage migration toward low-risk disease.
About ppm Prostata- new prostate cancers are estimated to be diagnosed ppm Prostata- in the USA. On the other hand, anterior tumors tend to be missed by TRUS biopsy until they grow to a substantial size and reach within 15—20 mm from the posterior margin of the prostate, leading to delayed diagnosis. Systematic TRUS biopsy has historically shown to underestimate the final Gleason grade of ppm Prostata- on histology following radical prostatectomy, leading to inaccurate risk stratification and selection of therapeutic options.
Its main use is in detecting post-biopsy hemorrhage. Bowel ppm Prostata- artefacts should be reduced by administering anti-peristaltic agents. Prostate imaging at 3T benefits from higher signal to noise ratio. Use of endorectal coil ERC is not an absolute requirement for cancer detection protocol, but is preferable at 1. Distention with liquids perflurocarbon or ppm Prostata- suspension will prevent susceptibility artefacts. Usually, about 60 cc of air or ppm Prostata- is required to distend the balloon.
It provides high spatial ppm Prostata- and defines the zonal ppm Prostata- differentiating the peripheral zone from the transition zone, the central zone, ejaculatory ducts, anterior fibromuscular stroma, seminal vesicles and the urethra.
The peripheral zone has high signal intensity on T2WI, reflecting its higher water content, and cancer in ppm Prostata- peripheral zone appears as an area of lower signal [ Figure 1a ]. However, low T2 signal in the ppm Prostata- zone may also be seen in benign abnormalities, including prostatitis, fibrosis, scar tissue, post-biopsy hemorrhage or post-irradiation.
The heterogenous appearance with multiple BPH benign prostate hyperplasia or benign enlargement of the prostate nodules makes assessment for cancer more difficult in the transition zone, especially for the less-experienced reader. Transition zone tumor. A year-old male with biopsy-confirmed Gleason 8 prostate carcinoma. The degree of intensity decrease on T2WI in the peripheral zone has been correlated with Gleason grade of tumor, with higher Gleason score components showing lower signal intensities, thereby playing a role in risk stratification of tumor.
Lawrence et al. Extracapsular extension of tumor. Axial T2-weighted image obtained with the ppm Prostata- coil shows the low signal tumor in the left peripheral zone ppm Prostata- minimal extension along the left neurovascular bundle arrow.
Diffusion-weighted MRI is a functional imaging tool that measures the random Brownian motion of water molecules in tissue. The apparent diffusion coefficient ADC on MRI or the net displacement of molecules quantifies the restriction of ppm Prostata- diffusion and is measured by acquiring at least two set of images with different magnetic field gradient durations and amplitudes b value. Multipoint b value analyses increase the accuracy of the calculated ADC at the expense of increased scanning time and decrease in signal to noise ratio SNR.
Limitations of DWI ppm Prostata- increased noise and anatomic distortion of the image, especially at higher b values. Studies have also shown ppm Prostata- inverse correlation between quantitative ADC values and Gleason score, and may therefore help in assigning accurate risk stratification for selection of therapeutic options.
Functional imaging DWI, DCE and magnetic resonance spectroscopic imaging [MRSI]and in particular DWI, may help to differentiate cancer from benign abnormalities such as prostatitis, fibrosis, scar tissue, post-biopsy hemorrhage or post-irradiation in the peripheral zone [ Figure 1b ]; therefore, DWI is considered as the dominant sequence for identifying tumors in the peripheral zone.
During DCE MRI, tumors demonstrate early and high-amplitude enhancement followed by rapid washout in some cases compared with normal tissue. DCE MRI images ppm Prostata- be evaluated by simple visual analysis in a qualitative manner on the raw data via scrolling through ppm Prostata- obtained images or on subtraction images, to look for early nodular and focal enhancement.
Alternatively, semi-quantitative parameters such as upslope gradient, peak enhancement and washout gradient can be calculated to generate a slope curve types A, B and C for assessment. Quantitative metric assessment may also be performed using pharmacokinetic Tofts models to estimate contrast concentration within the tissue. It provides the transfer constant K transwhich describes microvascular permeability and blood flow, and V ethe extracellular—extravascular compartment volume fraction or leakage ppm Prostata.
Quantitative assessment is valuable for assessing response to therapy when there are no changes to morphologic appearances. Because of overlap of enhancement pattern with benign conditions such as prostatitis in the peripheral zone and BPH nodules in the transition zone, DCE Ppm Prostata- is not considered as a dominant imaging sequence in isolation for ppm Prostata- of cancer, either in the peripheral zone or in the transition zone, and is often applied as an adjunct to Ppm Prostata- and DWI findings in mp-MRI.
Early nodular enhancement on DCE MRI following focal therapy post-treatment, the area becomes fibrotic and DWI is generally not useful in assessment [ Ppm Prostata- 4 ] and in the prostate bed following prostatectomy helps identify the site of local recurrence.
Residual tumor following focal therapy. Dynamic contrast-enhanced ppm Prostata- subtraction image 6 months following focal therapy shows a nodular area of enhancement at the margin of the treatment. Magnetic ppm Prostata- fusion biopsy of the area ppm Prostata- performed, which revealed Gleason 6 disease. On MRSI of the prostate, the ppm Prostata- peaks in the spectra are from protons in citrate resonates at 2. Ppm Prostata- signals may also be identified. In cancer, choline signals are elevated while citrate signals decrease, in comparison with benign tissue.
Ppm Prostata- image interpretation, the choline plus creatine-to-citrate ratio is often used as a metabolic biomarker, although it is more reliable in the peripheral zone, which has high citrate levels. Considerable magnetic field distortions may occur from hemorrhage and therefore the exam has to be performed after sufficient delay following biopsy.
MRSI needs more time and expertise than other MR functional techniques; therefore, its ppm Prostata- application is ppm Prostata. Although the individual ppm Prostata- are useful, T2WI in combination with two functional sequences has been shown to provide better characterization of tumor in the prostate.
Pooled sensitivity and specificity were 0. While several studies have shown the benefit of functional imaging in detection of prostate cancer ppm Prostata- the peripheral zone,[ 263149 ] functional imaging may have a limited role in evaluating cancers in the transition zone on mp-MRI because of the heterogenous appearance and enhancement secondary to benign prostatic hyperplasia.
Hoeks et al. In another study, the authors reported that adding DWI to T2WI improved the accuracy of detecting prostate cancer in the transition zone. Tumor volume is a documented prognostic factor for prostate cancer outcome, and is its correct estimation is mandatory for success of focal therapy,[ ppm Prostata- ] the new organ-sparing treatment technique that aims to selectively ablate locally confined, clinically significant index lesions, while sparing the rest of the prostate gland and the surrounding structures.
Histologic architecture of the tumor affects quantitative MRI findings and is known to be a major predictor of tumor visibility on mp-MRI. Studies have shown higher interobserver reproducibility in the experienced readers than for less-experience readers for ppm Prostata- the PI-RADS and the Likert scoring systems.
Use of mp-MRI in men with no previous biopsy has been studied, but the cost-effectiveness and the true value in this patient population is yet to be determined. Their results suggested comparable healthcare costs in the two ppm Prostata- but an improved quality of life QoL in the imaging arm.
The benefit in QoL is derived from decrease in overdiagnosis ppm Prostata- overtreatment in the imaging arm. In a recently reported randomized prospective study by Panebianco et al. In the patients in the imaging arm who had a negative MRI, none had Gleason 7 disease on saturation biopsy. In another study, Haffner et al. In a meta-analysis including 14 studies and patients, the mean cancer detection rate following a ppm Prostata- biopsy was The positive predictive value of mp-MRI in these ppm Prostata- ranged from 17 to Similarly, Vourganti et al.
In their study, targeted biopsy using MRI-TRUS fusion upgraded in 28 patients and detected additional significant cancer in 12 patients, not detected by systematic biopsy. Recently, Sonn et ppm Prostata. There is mounting evidence along with the recent literature suggesting that effectiveness of ppm Prostata- when used along with PSA, followed by targeted biopsy of the MRI-visible lesion, is a ppm Prostata- alternative to systematic TRUS biopsy in the diagnostic pathway for prostate cancer detection and therefore benefits the diagnosis of cancer.
The largest benefit may come from reduction of unnecessary biopsies NPV ppm Prostata- mp-MRI for clinically significant cancerwhich ppm Prostata- in turn prevent overdiagnosis and overtreatment. It also has the potential to ppm Prostata- the number of missed clinically significant cancers and improves risk stratification; therefore, it provides a more accurate therapeutic option to the patient.
As we move toward personalized medicine, use of MRI to biopsy each man's prostate differently rather than based ppm Prostata- a pre-defined 12 core seems to be supported in the recent literature. Source of Support: Nil. Conflict of Interest: None declared. National Center ppm Prostata- Biotechnology InformationU. Journal List Indian J Urol v.
Indian J Urol. Sangeet Ghai and Masoom A. Haider 1. Masoom A. Author information Copyright and License information Disclaimer. For correspondence: Dr. E-mail: ac. This is ppm Prostata- open-access article distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.
This article has been cited by ppm Prostata- articles in PMC. Abstract Multiparametric-magnetic resonance imaging mp-MRI has shown promising results in diagnosis, localization, risk stratification and staging of clinically significant prostate cancer. Open in ppm Prostata- separate window. Figure 1. Figure 2. Figure 3. Figure 4. Spectroscopic Imaging On MRSI of the prostate, the dominant peaks in the spectra are from protons ppm Prostata- citrate resonates at 2. Cancer statistics, CA Cancer J Clin.
Screening for prostate cancer: A review of the evidence for the U. Preventive Services Task Force. Ann Intern Med. Multiparametric magnetic resonance imaging vs. Urol Oncol.