MRI of the prostate has become a common test ordered to investigate the cause of an elevated PSA. PSA stands for prostate specific antigen. It is produced by the prostate and is elevated when there is something wrong with the prostate like cancer, inflammation, or enlargement.
Why is Prostate MRI done?
MRI of the prostate is a common test to look for cancer. It can identify suspicious areas that look like cancer. There is a scale we use that tells us the level of suspicion for each area in the prostate. This ranges from 1 being very low suspicion, to 5 being highly suspicious for cancer. The radiology doctor who reads the test will mark those areas and grade them so that they can be biopsied.
MRI of the Prostate Helps with Biopsy
The marked areas on the MRI allow the urology doctor to target an area of the prostate gland for biopsy. The urology doctor will sample those areas and provide tissue to the pathology doctor who will make a final diagnosis of cancer or something benign. MRI is therefore very helpful in making the diagnosis of prostate cancer. It also helps with the biopsy being higher yield.
The urology doctor will also sample other areas of the prostate gland in addition to those marked. Some prostate cancers do not show up on prostate MRIs. Therefore they will often sample multiple areas in the prostate gland in addition to those marked by the radiology doctor.
What are some other causes of elevated PSA we can see on MRI?
MRI of the prostate also can tell us if there is inflammation which can also lead to elevated PSA. This often looks like more diffuse areas of abnormality along the prostate periphery called the peripheral zone. This is called prostatitis. Cancer can however coexist with prostatitis.
MRI also lets us measure the size of the gland. We can also see the nodules in the central gland which contribute to this enlargement. This is called benign prostatic hyperplasia or BPH. This can lead to urinary symptoms like frequent urination, incomplete emptying of the bladder and weak urinary stream.
MRI of the prostate therefore allows us a non invasive way of determining some of the causes of elevated PSA. Prostate MRI is good at finding clinically significant cancers which pose a threat to health. MRI can also allow us to find some alternative causes like enlargement or inflammation.
MRI of the prostate helps the urology doctor to target the most suspicious areas when he decides to biopsy the gland. This makes the likelihood of diagnosing a clinically significant cancer higher. Doing a biopsy of the gland blindly without an MRI may reduce the ability to make a diagnosis since areas of the gland will not be sampled.