Assessing the image quality of pelvic MR images acquired with a flat couch for radiotherapy treatment planning

• Published in: British journal of radiology Vol. 84; no. 1004; pp. 750 - 755
• Main Authors: MCJURY, M, O'NEILL, A, LAWSON, M, MCGRATH, C, GREY, A, PAGE, W, O'SULLIVAN, J. M
• Format: Journal Article
• Language: English
• Published: London British Institute of Radiology 01.08.2011; The British Institute of Radiology
• Subjects: Biological and medical sciences; Diseases of the urinary system; Genital system. Mammary gland; Humans; Magnetic Resonance Imaging - standards; Male; Medical sciences; Middle Aged; Patient Positioning - methods; Pelvis; Phantoms, Imaging; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - radiotherapy; Radiographic Image Enhancement; Radiotherapy Planning, Computer-Assisted - instrumentation; Radiotherapy Planning, Computer-Assisted - methods; Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects); Reproducibility of Results; Human; Urinary system disease; Prostate disease; Male; Malignant tumor; Radiotherapy; Nuclear magnetic resonance imaging; Image quality; Treatment; Pelvic cavity; Medical imagery; Male genital diseases; Prostate cancer; Treatment planning; Cancer; Test object
• ISSN: 0007-1285; 1748-880X
• DOI: 10.1259/bjr/27295679

To improve the integration of MRI with radiotherapy treatment planning, our department fabricated a flat couch top for our MR scanner. Setting up using this couch top meant that the patients were physically higher up in the scanner and, posteriorly, a gap was introduced between the patient and radiofrequency coil. Phantom measurements were performed to assess the quantitative impact on image quality. A phantom was set up with and without the flat couch insert in place, and measurements of image uniformity and signal to noise were made. To assess clinical impact, six patients with pelvic cancer were recruited and scanned on both couch types. The image quality of pairs of scans was assessed by two consultant radiologists. The use of the flat couch insert led to a drop in image signal to noise of approximately 14%. Uniformity in the anteroposterior direction was affected the most, with little change in right-to-left and feet-to-head directions. All six patients were successfully scanned on the flat couch, although one patient had to be positioned with their arms by their sides. The image quality scores showed no statistically significant change between scans with and without the flat couch in place. Although the quantitative performance of the coil is affected by the integration of a flat couch top, there is no discernible deterioration of diagnostic image quality, as assessed by two consultant radiologists. Although the flat couch insert moved patients higher in the bore of the scanner, all patients in the study were successfully scanned.