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Background: Since 2008 primary care physicians (GPs) in our region have been allowed open access to knee MRI scans. There are questions about whether this changes referral practice and if it is an effective use of resources. Purpose: To describe the change in demographics of patients referred for knee MRI following implementation of a new referral pathway. Study Type: Retrospective observational study. Population: All primary care referrals between 2008 and 2015 for knee MRI from a population of 900,000. Field Strength/Sequence: Not applicable. Assessment: Demographic profile and number of knee MRI referrals and subsequent arthroscopies. Statistical Tests: Comparisons between urban and rural populations used the t-test. Test for normality used Shapiro–Wilks. Comparison between abnormal MRI proportions used a chi-squared test. Results: There were 23,928 knee MRI referrals (10,695 from GPs) between 2000 and 2015. MRI knee referrals rose from 210 in 2008 to 2379 in 2015. The average age of the patient decreased from 46.8 (SD = 14.9) in 2008 to 41.3 (SD = 14.7) in 2015. Conversion to arthroscopy declined from 15.4% to 10.2%, but there was no significant change in abnormal scan proportion. Conversion rates showed no significant difference between rural (9.6%) and urban populations (10.5%). Referral rates were significantly higher in low socioeconomic status areas (47.3% vs. 34.6%). The median referral rate per 1000 patients was 13.8 (interquartile range = 8.4). Referral rates varied widely between practices. Data Conclusion: Despite a large rise in knee MRI referrals from primary care, there has been no substantial change in the age profile, suggesting that there has been no increase in inappropriate referral of elderly patients in whom MRI is unlikely to influence management. A modest decrease in the conversion rate to arthroscopy may be reasonably offset against a decrease in secondary care referrals. Socioeconomic status of the target population must be considered when planning primary care knee MRI services. Level of Evidence: 4. Technical Efficacy Stage: 6. J. Magn. Reson. Imaging 2019.

Purpose To measure the test–retest reliability of rapid (

BACKGROUND: The aim of this study was to compare two different methods of quantitative assessment of tibial subchondral bone in osteoarthritis (OA): statistical texture analysis (sTA) and trabecular microarchitecture analysis (tMA). METHODS: Asymptomatic controls aged 20-30 (n = 10), patients aged 40-50 with chronic knee pain but without established OA (n = 10) and patients aged 55-85 with advanced OA scheduled for knee replacement (n = 10) underwent knee MR imaging at 3 Tesla with a three-dimensional gradient echo sequence to allow sTA and tMA. tMA and sTA features were calculated using region of interest creation in the medial (MT) and lateral (LT) tibial subchondral bone. Features were compared between groups using one-way analysis of variance. The two most discriminating tMA and sTA features were used to construct exploratory discriminant functions to assess the ability of the two methods to classify participants. RESULTS: No tMA features were significantly different between groups at either MT or LT. 17/20 and 11/20 sTA features were significantly different between groups at the MT/LT, respectively (P

PURPOSE: To define the range of quantitative pharmacokinetic parameters in normal-healing bone with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). DCE-MRI is an established technique for characterizing abnormal tissue microvasculature within solid tumors, but has also shown promise for assessing bone and bone marrow. MATERIALS AND METHODS: In this study ethical approval for eight patients was obtained. Inclusion criteria were an extra-articular distal radial fracture in patients aged 20-50 years which had united by 6 weeks in plaster cast. This was assessed by an experienced orthopedic surgeon. DCE-MRI was performed at 1.5T 6 weeks after initial injury. The transfer constant (K(trans) ), transfer rate (Kep ), and initial area under the curve (IAUC) values for the fracture site and adjacent marrow were obtained for each patient. RESULTS: The mean T1 , K(trans) , Kep , and IAUC at the fracture site were 1713 (standard deviation [SD] 645), 0.09 (SD 0.07), 0.17 (SD 0.17) and 4.9 (SD 4.4). The relative standard deviation (RSD) for the fracture site ranged from 0.38 to 0.97 and for the adjacent marrow ranged from 0.95-3.88. Within each patient the range of RSDs was 0.04-0.42 for T1 , 0.26-0.91 for K(trans) , 0.14-1.06 for Kep , and 0.35-0.96 for the IAUC. CONCLUSION: Pharmacokinetic measures of perfusion can be obtained from healing fractures using DCE-MRI with "excellent" intraclass correlation coefficients for inter- and intrarater reliability. The use of these perfusion parameters is limited by wide patient-to-patient variation and slice-to-slice variation within patients. J. Magn. Reson. Imaging 2015.