Intra-fractional prostate motion on cine MRI during radiotherapy treatment
Biochemical recurrence after treatment for prostate cancer PCa is a significant issue. Early diagnosis of local recurrence is important for making prompt treatment decisions and is strongly associated with patient prognosis.
Without salvage therapy, the average time from development of local recurrence to distant metastasis is approximately 3 years. Biochemical recurrence does not differentiate local recurrence from systemic disease; there is MRI della prostata sf reliable way to clinically diagnose MRI della prostata sf recurrence.
Recent advances in multiparametric MRI mp-MRI techniques have markedly improved detection of local recurrence following therapy. Therefore, the purpose MRI della prostata sf this pictorial review is to discuss the MRI findings of locally recurrent PCa and its mimics, emphasizing the key MRI features that help to MRI della prostata sf local recurrence from its mimics. However, a wide variety of entities can mimic recurrent prostate cancer PCa at mp-MRI creating a diagnostic challenge.
Following radical prostatectomy, mimics may include, but are not limited to, fibrotic scar, prominent vascular structures, granulation tissue, retained seminal vesicles SVs and residual prostatic tissue. After radiation therapy, mimics including focal regions of severe post-treatment changes, well-preserved hypertrophic nodules in the central gland and marked hypertrophic fibromuscular stroma may be encountered.
Since the early diagnosis of local recurrence is strongly associated with patient prognosis, 1 recognition of the MRI findings of locally recurrent PCa and its mimics, along with the key MRI features that help to differentiate local recurrence from its mimics, is important in guiding prompt clinical management.
Many different options exist for creating appropriate prostate mp-MRI protocols, including the use of endorectal coils, different b -values during diffusion-weighted imaging DWI and different acquisition parameters during contrast administration. At our institution, prostate mp-MRI is performed with a 1. The standard protocol includes T 2 weighted sequences T2WI acquired in axial, coronal and sagittal planes covering the SVs and prostate at 3-mm section thickness. Multiple options currently exist for the treatment of newly diagnosed, clinically localized PCa.
Radical prostatectomy has been the most commonly used treatment for healthy males younger than the age of 70 years, with organ-confined PCa. External beam radiation therapy in combination with androgen-deprivation therapy is a standard approach for intermediate- and high-risk PCa.
Prostate brachytherapy is most commonly used as monotherapy for patients with low- or intermediate-risk PCa. In those patients in whom focal therapy is utilized for cure, the disease should be low risk and low volume in a targetable area of the prostate. Recurrent PCa in the surgical bed following radical prostatectomy is common.
A focus of soft tissue in the prostate surgical bed demonstrating slightly high T 2 signal compared with the pelvic muscles with contrast wash-in and wash-out at DCE MRI is suggestive of local recurrence Figure 1. In other words, some recurrences may not be appreciated owing to small size. In these MRI della prostata sf, abnormal enhancement may be the only sign of disease recurrence.
Recurrent prostate cancer in the surgical bed. The patient is status post radical prostatectomy with a slowly rising prostate-specific antigen to 0. All findings are consistent with local recurrence. Recurrent PCa in patients after radiation therapy is also common. Given these challenges, it is important to be familiar with features of focal recurrence at mp-MRI.
A mass-like lesion with low T 2 signal intensity, commonly in the same location of the pre-treatment tumour, and demonstrating MRI della prostata sf arterial enhancement with rapid wash-out at DCE MRI, with or without diffusion restriction, is highly suggestive of recurrent cancer Figure 2. The patient is status post external beam radiation therapy with recent elevation of prostate-specific antigen to 2. Target biopsy confirmed recurrent prostate cancer Gleason score 7.
Cryotherapy, high-intensity focused ultrasound and laser treatment are focal therapies that have received MRI della prostata sf attention in recent years. At the site of focal treatment, a heterogeneous, but predominantly low T 2 signal intensity area, may be seen with no or heterogeneous enhancement.
Of note, follow-up mp-MRI over a 6-month period after focal therapy such as high-intensity focused ultrasound may provide important information about the completeness of tumour MRI della prostata sf and early post-treatment changes. Recurrent prostate cancer MRI della prostata sf in the central gland. The patient is status post cryotherapy with recent elevation of prostate-specific antigen to 1. The entire prostate P is deformed secondary to the prior cryotherapy. Recurrent PCa following various types of treatment may be difficult to diagnose due to extensive post-treatment changes.
Of course, the local salvage treatment only will be performed when clinicians are certain that there are no distant metastases present. Choline positron emission tomography-CT is a sensitive test in excluding distant metastasis, such as those in lymph nodes or bones, in these patients. Fibrotic scar is commonly present in the surgical bed appearing as a soft tissue focus mimicking a recurrence. There is no diffusion restriction in the MRI della prostata sf although the diffusion-weighted images may be degraded due to surgical clips.
Fibrotic scar mimicking prostate cancer. Axial T 2 demonstrates a low T 2 signal intensity mass arrow similar to that of the adjacent muscle M in the left side of the surgical bed without enhancement at dynamic contrast enhanced MRI not shown consistent with fibrotic scar. After removal of the prostate, prominent vascular structures may be present in the surgical bed and may demonstrate rapid contrast wash-in and wash-out, mimicking recurrence, particularly on the post-processed DCE MRI images.
These MRI della prostata sf structures do not usually have the appearance of a soft-tissue mass MRI della prostata sf the surgical bed at T2WI and are frequently located in the anterior and lateral aspects of the surgical bed with an elongated and continuous appearance noted at DCE MRI Figure 5.
In contrast, a local recurrence appears as a rounded area with enhancement. Prominent venous plexus. Granulation tissue in the surgical bed may occasionally be present, commonly in the perianastomotic region, and shows high signal on T2WI relative to muscle, mimicking a local recurrence Figure 6. Granulation tissue mimicking prostate cancer. The patient is status post radical prostatectomy with slowly rising prostate-specific antigen to 0.
Axial T 2 shows a soft-tissue focus arrows with slightly high T 2 signal intensity relative to the adjacent muscle and posterior to the bladder B without significant enhancement at dynamic contrast enhanced MRI not shown. Target biopsy confirmed granulation tissue. Retained seminal vesicle SV mimicking prostate cancer. Axial T 2 shows a homogeneous slightly high T 2 signal intensity area arrow in the expected location of the right SV without evidence of enhancement at dynamic contrast enhanced MRI not shown.
The bladder MRI della prostata sf noted B. Target biopsy confirmed no tumour. A small amount of normal prostatic tissue may be present in the surgical bed following radical prostatectomy and can be responsible for slight elevation of prostate-specific antigen PSAmimicking recurrent PCa.
Residual normal prostate tissue mimicking recurrent prostate cancer. The patient is status post radical prostatectomy with prostate-specific antigen of 0. Following radiation therapy, focal areas of marked low T 2 signal intensity, lower than the rest of the treated prostate, are common due to the uneven distribution of severe post-radiation changes 10 and treated tumour, 6 mimicking recurrence Figure 9a.
These areas of severe post-treatment changes do not demonstrate diffusion restriction Figure 9b or abnormal enhancement, distinguishing them from focal recurrence. Focal region of severe post-treatment changes mimicking recurrent prostate cancer.
The patient is status post external beam radiation therapy with prostate-specific antigen of 0. Following radiation therapy, hypertrophic nodules MRI della prostata sf the central gland may be well preserved with little or no radiation-related changes. These nodules usually demonstrate diffusion restriction and rapid contrast wash-in and wash-out Figure 10amimicking recurrence.
These nodules can be differentiated from recurrence by well-defined margins Figure 10b on T2WI, a different location from the pre-treated tumour, and contrast enhancement similar to the rest of the central gland. Hypertrophic nodule in the central gland. The patient is status post external radiation therapy. Digital rectal exam demonstrated a nodule in MRI della prostata sf right side of the prostate.
Target biopsy confirmed no recurrence. Following radiation therapy, the prostate may be small and atrophic. However, the anterior fibromuscular stroma may be hypertrophic with MRI della prostata sf mass-like appearance. The enlarged stroma has a low T 2 signal intensity Figure 11a due to fibrotic content with diffusion restriction Figure 11b MRI della prostata sf a recurrence. The key features differentiating stroma from recurrence are that the stroma is low signal intensity on T2WI, lower than that of most recurrences; is usually located anteriorly at the midline; is symmetric or nearly symmetric; and does not enhance at DCE MRI.
Hypertrophic fibromuscular stroma mimicking recurrence. The patient is status post-radiation therapy with recent elevation of prostate-specific antigen to 1.
The generalized decreased T 2 signal intensity MRI della prostata sf the peripheral zone P is consistent with radiation changes. The mimics of focal recurrence may create a significant diagnostic challenge in daily practice. Familiarity with key MRI della prostata sf features of mimics Table 2 is important to avoid unnecessary intervention. Key MR features that will help in differentiating the mimics from recurrent prostate cancer. National Center for Biotechnology InformationU.
Journal MRI della prostata sf Br J Radiol v. Br J Radiol. October ; 88 : MRI della prostata sf online Sep 8. Author information Article notes Copyright and License information Disclaimer. Corresponding author. Mark Notley: gro. Address correspondence to: Dr Mark Notley. E-mail: gro. Published by the British Institute of Radiology. This article has been cited by other articles in PMC.
Abstract Biochemical recurrence after treatment for prostate cancer PCa is a significant issue. Following radical prostatectomy Recurrent PCa in the surgical bed following radical prostatectomy is common. Open in a separate window. Figure 1. Following radiation therapy Recurrent PCa in patients after radiation therapy is also common.
Figure 2. Following MRI della prostata sf therapy MRI della prostata sf, high-intensity focused ultrasound and laser treatment are focal therapies that have received increased attention in recent years.