Journal highlights
The following are highlights from the current issues of RSNA’s peer-reviewed journals.
MRI-Guided Focal Therapy for Prostate Cancer
For patients with prostate cancer in a low-risk grade group, active surveillance is recommended, while for those in an intermediate-risk grade group, whole-gland radical prostatectomy or radiation therapy are commonly used. However, surgery and radiation therapy often cause erectile dysfunction and urinary and bowel problems.
Focal therapy (FT) is an emerging treatment for localized prostate cancer. It targets only the tumor and can spare the neurovascular bundle and sphincter so urinary incontinence and erectile dysfunction are less common. MRI guidance for FT is an emerging treatment option where MRI can be coupled with an energy source to destroy cancer cells.
In an article published in Radiology, Sangeet Ghai, MD, Toronto General Hospital, Ontario, and colleagues examined the use of MRI-guided FT for accurate targeting of localized clinically significant prostate cancer while preserving healthy prostate tissue.
In this single-center prospective phase II trial, men with localized unifocal intermediate-risk prostate cancer underwent transrectal MRI-guided focused US between July 2016 and July 2019. Participants in this study completed quality-of-life questionnaires at six weeks and at five, 12, 18 and 24 months after treatment.
Multiparametric MRI and targeted and systematic biopsies were performed at 24 months. After two years of treatment, 91% of participants had no clinically significant prostate cancer at the treatment site and 84% of participants had no cancer in the entire gland.
“The majority of male participants treated with MRI-guided focused US for localized intermediate-risk prostate cancer were negative for clinically significant prostate cancer at biopsy two years after treatment and had no clinically significant decline in quality of life. Results of this study will help in its widespread adoption in appropriately selected patients,” the authors conclude.
Read the full article, “MRI-guided Focused Ultrasound Focal Therapy for Intermediate-Risk Prostate Cancer: Final Results from a 2-year Phase II Clinical Trial.” Follow the Radiology editor on X @RadiologyEditor.
Images in a 56-year-old man with biopsy-confirmed Gleason grade group 7 (3+4) prostate cancer. (A) Pretreatment axial T2-weighted fast spin-echo MRI scan (repetition time msec/echo time msec, 3820/97) and (B) apparent diffusion coefficient map acquired with a 3-T scanner (Skyra Fit; Siemens Healthineers) show the tumor in the left transition zone (arrows). (C) Intraoperative 1.5-T MRI scan (Excite Twinspeed; GE HealthCare) shows the contoured rectal wall (red line), prostate margin (blue outline) and region of interest (orange outline). (D) Intraoperative MRI scan shows a focused ultrasound beam path (blue) overlaid on the treatment plan. The rectangular boxes show each sonication spot. (E) Thermal map obtained during treatment shows heat deposition color-coded in red and overlaid on the sonication spot. (F) Axial gadobutrol (Gadovist; Bayer)–enhanced MRI scan obtained immediately after treatment shows the devascularized ablated volume (arrows). (G) Corresponding T2-weighted fast spin-echo 3-T MRI scan (7640/97; Skyra Fit, Siemens Healthineers) obtained at 24 months after ablation shows fibrosis and volume loss in the left transition zone (arrows). Findings from a biopsy showed scar tissue, negative for malignancy at the treatment site.
https://doi.org/10.1148/radiol.231473 ©RSNA 2024
Response Evaluation Criteria in Gastrointestinal Cancer
Gastrointestinal tumors are common and represent 35% of all cancer-related deaths. As gastrointestinal malignancy management has evolved, tumor response assessment has advanced beyond size-based assessments to include features like tumor enhancement and functional data from PET and diffusion-weighted imaging.
Understanding imaging methods, cancer treatments and tumor biology is necessary for the accurate interpretation of tumor response in gastrointestinal malignancy.
Some gastrointestinal malignancies require assessment with tumor-specific criteria when evaluating response, often to guide clinical management. Some anatomic measurements can underestimate therapeutic response when applied in molecular-targeted therapies, which can cause tumors to exhibit morphologic changes often without significant reduction in size. Awareness of the pitfalls when interpreting gastrointestinal tumor response is required to correctly interpret response assessment imaging and guide appropriate treatment.
In an article published in RadioGraphics, Francesca Castagnoli, MD, Royal Marsden Hospital, London, and colleagues review the traditional and evolving criteria for tumor response assessment in gastrointestinal cancers.
The authors looked at different classes of systemic treatments for gastrointestinal cancer including chemotherapy, targeted therapy and immunotherapy. The choice of regimen depended on the primary site, molecular characteristics and stage of disease.
However, there are a variety of pitfalls that may be encountered when assessing treatment response. Timing of baseline imaging with respect to commencing treatment is an important but often overlooked pitfall.
“Response assessment of gastrointestinal malignancy poses specific challenges, particularly in the era of novel therapeutics and functional imaging. To overcome these, modified response criteria that evaluate not only tumor size but also tumor function have been proposed,” the authors conclude.
Read the full article, “Response Evaluation Criteria in Gastrointestinal and Abdominal Cancers: Which to Use and How to Measure.” This article is also available for CME at RSNA.org/Learning-Center. Follow the RadioGraphics editor on X @RadG_Editor.
Colorectal liver metastasis after stereotactic body radiation therapy in a 73-yearold patient. (A, B) Axial T2-weighted (A) and hepatobiliary phase (B) MR images show a solitary lesion in segment IVb. (C, D) Axial posttreatment T2-weighted (C) and hepatobiliary phase (D) MR images show a 28% reduction in size that according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 would qualify as stable disease. However, the tumor is clearly responding.
https://doi.org/10.1148/rg.230047 ©RSNA 2024
Improving Image Quality of Coronary CT Angiography
Iterative reconstruction, introduced more than a decade ago, has reduced image noise and reduced the radiation dose of CT scans. With improvements in computer performance, model-based iterative reconstruction (MBIR) has become available. MBIR has been advantageous in coronary CT angiography because it improves spatial resolution while reducing image noise. However, it has a long reconstruction time.
Recently, deep learning reconstruction (DLR) has become available, and unlike MBIR, this method could reduce image noise within a short reconstruction time. Furthermore, super resolution DLR (SR-DLR) has been introduced to improve spatial resolution.
In an article published in Radiology Advances, Nobuo Tomizawa, MD, PhD, Juntendo University Graduate School of Medicine, Tokyo, and colleagues compare the objective and subjective image quality and diagnostic performance of normal-dose MBIR and reduced-dose SR-DLR for coronary artery stenosis in coronary CT angiography.
In the single-center retrospective study, 52 patients underwent coronary CT angiography with subsequent invasive coronary angiography between January and November 2022. The first 25 patients were scanned with a standard dose using model-based iterative reconstruction. The last 27 patients were scanned with a reduced dose using SR-DLR. Per-patient objective and subjective image qualities were compared.
The authors found that SR-DLR reduced image noise and improved the subjective image quality compared with MBIR.
“The present exploratory analysis indicates that SR-DLR could improve objective and subjective image quality with lower tube current settings than MBIR with similar diagnostic performance to diagnose morphological coronary stenosis in coronary CT angiography,” the authors conclude.
Read the full article, “Super-resolution deep learning reconstruction to improve image quality of coronary CT angiography.”
Radiology Advances: Sharing Research Further, Faster
Published in association with Oxford University Press, Radiology Advances is RSNA’s first journal dedicated solely to open access articles. The journal’s high-quality, peer-reviewed content is made publicly available—exclusively online—offering easier access to timely radiology research.
With a mission to improve patient health and outcomes through timely and open dissemination of new knowledge in radiology and the imaging sciences, Radiology Advances publishes primarily original multidisciplinary research articles with a focus on emerging topics, cross-cutting and innovative research.
Increase the impact of your research and reach a broader audience faster—learn more and submit your work to Radiology Advances.