Prostate mpMRI detects local recurrence after LDR brachytherapy
Low dose rate (LDR) brachytherapy is commonly used for the treatment of prostate cancer. Although most patients who receive LDR brachytherapy for prostate cancer will be cured of their disease, biochemical recurrence occurs in 3%–13% of men undergoing monotherapy. New research demonstrates the efficacy of multiparametric magnetic resonance imaging (mpMRI) for detecting local recurrence of prostate cancer after LDR brachytherapy. The study is published in the journal Diagnostic and Interventional Radiology.
MRI has an increasing role in the diagnosis and management of prostate cancer. However, because of concern for MRI artefact caused by brachytherapy seeds, mpMRI is rarely used in the setting of biochemical recurrence following this treatment. Researchers hypothesised that mpMRI would be effective in identifying locally recurrent cancer in this setting; they conducted a multireader study to evaluate the diagnostic performance of mpMRI for local recurrence following LDR brachytherapy.
In this study, 19 patients with biochemical recurrence after LDR brachytherapy underwent 3T endorectal coil mpMRI with T2-weighted imaging, dynamic contrast-enhanced imaging (DCE) and diffusion-weighted imaging (DWI) with pathologic confirmation. Prospective reads by an experienced prostate radiologist were compared with reads from four radiologists of varying experience. Readers identified suspicious lesions and rated each MRI detection parameter.
The researchers reported these key findings:
• Pathologically confirmed recurrence was found in 15 of 19 patients. LDR brachytherapy recurrences identified by mpMRI were frequently located in the transition zone (41%) and seminal vesicles (32.3%).
• At the patient level, mpMRI correctly detected pathologically confirmed lesions with a sensitivity of 88% for all lesions and a specificity of 75% for highly suspicious lesions.
• At the lesion level, mpMRI demonstrated a high cancer-detection rate of 78.7% for highly suspicious lesions.
• Radiologists of varying experience demonstrated 54.4% agreement when detecting recurrent cancers at the patient level.
mpMRI includes a number of sequences and the researchers say it is possible that the artefact introduced by brachytherapy seeds may further alter the performance of certain sequences while minimally impacting others. Radiation-induced changes have been demonstrated to cause diffuse T2-weighted signal hypointensity, limiting the diagnostic capability of T2-weighted imaging.
"Indeed, in our study T2-weighted imaging did not perform as well as other parameters, but interestingly, DWI trended towards a higher cancer detection rate at 70% compared with 66.6% for T2-weighted imaging and 64.9% for DCE," the researchers write.
Although artefact is observed, mpMRI can still be performed and may provide useful information following LDR brachytherapy, according to the researchers, noting that patterns of recurrence suggest anterior prostate as well as seminal vesicles should be areas of focus for optimising initial diagnosis and treatment as well as detecting recurrence.
For brachytherapy practitioners, understanding the patterns of local recurrence after treatment may inform patient selection or alter implant techniques in certain cases to optimise dosimetry.
Source: Diagnostic and Interventional Radiology
Image Credit: Rock mc1
Published on : Tue, 23 Jan 2018
Print as PDF
Due to the complex nature of the spine, surgeries may be particularly difficult and call for careful preparation for better outcomes. The spineEOS online software provides a 3D visualization of the patient’s spine in its current state as well as a literature-based,...
The TE7 touch screen ultrasound system is designed to provide superior quality imaging for rapid patient-care decisions. Intuitive gesture controls and efficient focused point-of-care exams minimize the user learning curve, with no need to navigate a...
Samsung’s advanced premium ultrasound system for Radiology that provides enhanced image quality, and convenience for medical and radiology professionals. The RS85 features MV-Flow technology, which detects blood flow in microvascular, and S-Shearwave...
Powered by the most revolutionary ZONE Sonography® Technology, Resona 7’s new ZST+ platform brings the ultrasound image quality to a higher level by zone acquisition and channel data processing. Resona 7 also provides clinical research with the revolutionary...
THE VEVO MD IS THE WORLD’S FIRST ULTRA HIGH FREQUENCY ULTRASOUND SYSTEM DESIGNED FOR CLINICAL USE WITH FREQUENCIES UP TO 70 MHz. This groundbreaking technology opens up new possibilities for medical imaging that have never been seen before. Whether imaging...