From the Guidelines
Computed tomography (CT) imaging is not the primary modality for detecting early prostate cancer, but it can show signs of advanced disease, including prostate enlargement, irregular contour, and extracapsular extension into adjacent structures, as well as regional lymph node enlargement, bone metastases, and distant metastases. The most common CT findings in prostate cancer include 1:
- Prostate enlargement with irregular contour
- Focal areas of low attenuation within the prostate gland
- Obliteration of the normal fat planes surrounding the prostate
- Extracapsular extension into adjacent structures such as the seminal vesicles, bladder, or rectum
- Regional lymph node enlargement in the pelvis (typically nodes larger than 1 cm)
- Bone metastases appearing as sclerotic (dense) lesions
- Distant metastases to organs like the liver or lungs
However, CT is not the preferred imaging modality for prostate cancer detection or staging due to its poor soft tissue contrast resolution compared to MRI 1. CT is more useful for evaluating metastatic disease, treatment planning for radiation therapy, and assessing response to treatment in advanced cases 1. For initial prostate cancer detection and local staging, multiparametric MRI offers superior visualization of the prostate gland and can detect smaller tumors that CT would miss 1. According to the AUA/ASTRO guideline, clinicians should obtain a bone scan and either pelvic multi-parametric magnetic resonance imaging (mpMRI) or CT scan for patients with high-risk prostate cancer 1.
From the Research
CT Imaging of Prostate Cancer
The signs of prostate cancer on computed tomography (CT) imaging include:
- Focal mass-like enhancement on CT imaging, which may correspond to prostate neoplasms as revealed on multi-parametric MRI and follow-up targeted biopsy 2
- Areas of focal mass-like enhancement on CT imaging that directly correlate with prostate neoplasms as revealed on multi-parametric MRI and follow-up targeted biopsy 2
- Incidental focal areas of mass-like enhancement in the peripheral prostate detected on venous phase contrast-enhanced CT imaging, which may correlate with prostate neoplasm 2
Comparison with Other Imaging Modalities
CT imaging has been compared to other imaging modalities, including:
- Multi-parametric MRI, which is considered the current imaging standard for detection and staging of prostate cancer 2
- PET/CT, which has been shown to be more sensitive and specific than CT alone in detecting prostate cancer 3, 4
- Bone scintigraphy, which is often used in combination with CT to evaluate for metastatic disease 5, 3
Limitations of CT Imaging
The limitations of CT imaging in detecting prostate cancer include: