PROSTATE MRI AND PI-RADS

While CT scans show anatomical pictures of the body such as structures (kidney) or joints (knee, ankle, etc.), Magnetic Resonance Imaging shows a higher detail by imaging at the cellular level. By imaging at a cellular level the images created by MRI are much more detailed and create detailed images of the prostate anatomy whether there is prostatitis, prostate cancer or images of abnormal anatomy.

The magnets in MRIs vary in strength and are rated in Testla (T) units. The strength range is from 0.2T to 3T but the magnet strength used for most health care diagnoses is either 1.5T or 3T. The stronger magnetic field of the 3T provide more detail with less distracting non-pertinent imaging: 3T MRI imaging increases the signal strength and for imaging the prostate the images are more clear.

A prostate MRI is multi-parametric, meaning 4 different imaging techniques are used to evaluate the prostate. The imaging parameters that are used to evaluate the prostate are:

T1 weighted Helpful only in showing areas of hemorrhage from prior biopsies
T2 weighted Defines the different zones of the prostate including the neurovascular bundles. T2 low signal intensity signifies an abnormal area, or “lesion” better stated “Region of interest” (ROI).

In addition to the T1 and T2 images, functional images are needed. There are 2:

DWI Diffusion Weighted Imaging: how quickly water flows through the prostate. With abnormal areas there is restricted diffusion.
DCE Whether or not the ROI takes up the injected medication. If there is contrast enhancement there is increased risk of harboring prostate cancer.

MRI SCORING — PI-RADS
PROSTATE IMAGING REPORTING AND DATA SYSTEM

Radiologists report the findings on prostate MRI using the PI-RADS scoring system. Results are as follows:

PI-RADS SCORERISK OF HAVINGCLINICALLY SIGNIFICANT
PI-RADS 1 Very low 0%
PI-RADS 2 Low 0%
PI-RADS 3 Intermediate 9%
PI-RADS 4 High 23%
PI-RADS 5 Very high 63%

Prostate MRI is an imaging technique that adds much information about the prostate. This allows your urologist to make better informed recommendations when additional evaluation is needed.

The MRI that we recommend is a 3T large bore MRI approximately the size of an average CT. This means that the claustrophobia associated with the older generation MRIs is almost never a problem with the large bore recommended by your urologist. We have our patients MRIs peformed at the only free standing imaging center that has a 3T magnet as well.