Prostate Imaging in 3 Tesla MRI: The advantage of higher resolution

Prostate cancer is the second highest incidence of neoplasms for the male population, with an adjusted incidence rate of 50.78 new cases per 100 thousand inhabitants in 2020¹.
In order to reduce mortality, prostate cancer tracking is of utmost importance. As with other interventions in health, it can be associated with morbidity, which must be considered when applied, notably with regards to false-positive results, biopsy complications such as infections and bleeding, as well as overdiagnosis and overtreatment of non-clinically significant findings².
Tracking is historically based on laboratory analysis of prostate-specific antigen (PSA) and the subsequent anatomopathological study of the prostate gland for early diagnosis². In the last decade, multiparametric magnetic resonance of the prostate (mpMRI) has evolved for characterizing clinically significant neoplasms³, later consolidated by the American College of Radiology (ACR) in Prostate Imaging - Reporting and Data System (PI-RADS®), currently at version 2.1 of 2019⁴. Based upon these established requirements for sequences such as T2, diffusion weighted imaging (DWI), and if necessary, dynamic enhancement by paramagnetic contrast media (DCE) for proper analysis.
With PI-RADS, each change is classified in a score. For this purpose, acquiring images with excellent spatial and temporal resolution is imperative. In this aspect, due to the linear increase of these parameters with the field intensity, the magnetic resonance with 3 Tesla fields presents substantial advantages⁴. The use of endorectal coils, which were applied to increase the pelvic signal intensity,becomes unnecessary, while improving patient comfort andacceptance.
This assessment is not without setbacks. Artifacts caused by air and metallic materials such as patient implants can increase with the higher magnetic field. Furthermore, certain implantable devices, such as pacemakers and cardioverters, are not compatible with such MRI Systems.
The use of biparametric magnetic resonance imaging of the prostate (biMRI) is being studied, based only on T2W and DWI sequences⁵, reducing scanning time and eliminating the use of paramagnetic contrast medium. Furthermore, studies^{6, 7} demonstrate the possibility of using artificial intelligence.
In partnership with our institution, the Canon Vantage Galan 3T MRI System provides the best available tool for prostate analysis.
By providing 71 cm diameter of bore size, the availability of an MRI System with a spacious patient opening increases patient friendliness. Furthermore, this system provides low acoustic noise made possible by the fact that the gantry incorporates a vacuum technology called Pianissimo, to enhance acceptance and patient comfort.
Faced with varying patients’ imaging challenges, such as the inability to use anti-spasmodic medications to reduce the intestinal peristalsis and non-collaborative patient motion. The motion suppression technology, called JET, allows for image acquisition with diagnostic quality that would otherwise be determined inadequate for a proper prostate evaluation.
This document presents four clinical cases of patients examined with the Vantage Galan 3T, demonstrating the clinical usefulness and excellent image quality.

Case 1
71-year-old patient, Reporting Laboratory Results (Total PSA of 11,66 ng/ml).
Prostate measuring about 7.2 × 5.8 × 5.6 cm (volume: 122,3 cm³), with PSA density of 0.09 ng/ml/cm³.
An increase in the transition zone with pseudo nodular formations is observed, presenting usual enhancement by the paramagnetic contrast medium and without restriction to the free diffusion of water, related to benign prostatic hyperplasia (PI-RADS® score 1).
Lentiform formation in the left transition zone, in the middle third of the prostate, measuring 1.3 × 1.3 × 1.1 cm (AP × LL × CC), with moderate hypo signal on T2-weighted sequences, showing restriction to the free diffusion of water and early enhancement by the administered paramagnetic contrast medium, likely to represent a clinically significant neoplastic lesion (PI-RADS® score 4).

Case 2
62-year-old patient, complaining of pelvic pain and hematuria (total PSA 0.53 ng/ml).
Prostate measuring about 4.4 × 3.5 × 3.4 cm (volume: 27.3 cm³), with PSA density of 0.01 ng/ml/cm³.
An increase in the transition zone with pseudo nodular formations is observed, presenting usual enhancement by the paramagnetic contrast medium and without restriction to the free diffusion of water, related to benign prostatic hyperplasia (PI-RADS® score 1).
Presence of linear areas of hypo signal on T2-weighted sequences in the peripheral zone of both prostatic lobes, with greater enhancement by the paramagnetic contrast medium than the adjacent glandular tissue and without restriction to the free diffusion of water, related to foci of prostatitis (PI-RADS® score 2).

Case 3
63-year-old patient referring dysuria (Total PSA of 12.68 ng/ml).
Prostate measuring about 5.3 × 4.3 × 4.2 cm (volume: 50.0 cm³), with PSA density of 0.25 ng/ml/cm³. Presence of a nodular formation in the anterior peripheral zone on the left, in the middle third of the prostate, measuring 1.6 × 1.6 × 1.3 cm (CC × AP × LL), with hypo signal on T2-weighted sequences, showing restriction to the free diffusion of water and early enhancement by the administered paramagnetic contrast medium, bulging the prostatic contours, related to nodular formation with a very high probability of representing clinically significant neoplasm (PI-RADS® score 5).

Case 4
62-year-old patient referring dysuria, allergic to scopolamine (Total PSA of 6.5 ng/ml).
Prostate measuring about 4.2 × 3.6 × 3.1 cm (volume: 24.5 cm³), with PSA density of 0.26 ng/ml/cm³. An increase in the transition zone with pseudo nodular formations is observed, presenting usual enhancement by the paramagnetic contrast medium and without restriction to the free diffusion of water, related to benign prostatic hyperplasia (PI-RADS® score 1). Presence of linear areas of hypo signal on T2-weighted sequences in the peripheral zone of both prostatic lobes, with greater enhancement by the paramagnetic contrast medium than the adjacent glandular tissue and without restriction to the free diffusion of water, related to foci of prostatitis (PI-RADS® score 2).

Conclusion:
The high spatial resolution provided by the magnetic resonance imaging devices with 3 Tesla fields, combined with the high temporal resolution, allow for easier characterization of prostatic changes for adequate classification according to SCCR PI-RADS® V2.1 criteria. The ease of adapting protocols at 3 Tesla due to the increased Signal to Noise (SNR) allows for increased accuracy while removing the need for an endorectal coil for better acceptance by the patients. The refinement and improvement of exams allows for more accurate diagnoses, correlating significant imaging findings for pathological analysis.

Disclaimer: The clinical results, performance and views described in this document are the experience of the health care providers. Results may vary due to clinical setting, patient presentation and other factors. Many factors could cause the actual results and performance of Canon’s product to be materially different from any of the aforementioned.