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Objective To examine the association between distal radius fractures and tendon entrapment identified on computed tomography (CT) imaging. Patients and Methods After Institutional Review Board approval, we retrospectively reviewed distal radius fractures that underwent CT imaging from an electronic database between January 2006 to February 2018 at a single level 1 hospital trauma center. We categorized all distal radial fractures according to the AO-OTA (AO Foundation/Orthopaedic Trauma Association) classification. Distal upper extremity tendons were assessed for entrapment. Fisher's exact test was used for statistical analysis with significance at p < 0.05. Results A total of 183 distal radius fractures were identified in 179 patients. A total of 16 fractures (13 males and 3 females) were associated with tendon entrapment. Mechanism of injury included falls (n = 7), motor vehicle accidents (n = 6), dog bites (n = 2), and gunshot wound (n = 1). Entrapped tendons were limited to the extensor compartment and included the extensor pollicis longus (EPL; n = 11), extensor pollicis brevis (n = 1), extensor carpi ulnaris (n = 1), extensor carpi radialis longus (n = 1), and extensor digitorum communis (n = 2). The most commonly associated AO-OTA fracture pattern with tendon entrapment was complete articular radial fractures (2R3C; 69%), eight of which were simple articular with metaphyseal multifragmentary fractures (2R3C2). Of the distal radius fractures, 81% were associated with additional ulnar fractures of varying severity and displacement. Conclusion Approximately 8.7% of distal radius fractures were retrospectively identified to have tendon entrapment compared with a previously reported incidence of 1.3%. Wrist surgeons and radiologists should have higher suspicion for tendon entrapment and carefully review preoperative CT imaging for tendon entrapment in distal radius fractures especially if there is an intra-articular, multifragmentary injury pattern. Wrist surgeons and radiologists should also have increased suspicion for EPL tendon entrapments given its high incidence in association with distal radius fractures. Level of Evidence This is a Level III, retrospective cross-sectional study.

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Precise radiation therapy (RT) for abdominal lesions is complicated by respiratory motion and suboptimal soft tissue contrast in 4D CT. 4D MRI offers improved contrast although long scan times and irregular breathing patterns can be limiting. To address this, visual biofeedback (VBF) was introduced into 4D MRI. Ten volunteers were consented to an IRB‐approved protocol. Prospective respiratory‐triggered, T2‐weighted, coronal 4D MRIs were acquired on an open 1.0T MR‐SIM. VBF was integrated using an MR‐compatible interactive breath‐hold control system. Subjects visually monitored their breathing patterns to stay within predetermined tolerances. 4D MRIs were acquired with and without VBF for 2‐ and 8‐phase acquisitions. Normalized respiratory waveforms were evaluated for scan time, duty cycle (programmed/acquisition time), breathing period, and breathing regularity (end‐inhale coefficient of variation, EI‐COV). Three reviewers performed image quality assessment to compare artifacts with and without VBF. Respiration‐induced liver motion was calculated via centroid difference analysis of end‐exhale (EE) and EI liver contours. Incorporating VBF reduced 2‐phase acquisition time (4.7±1.0 and 5.4±1.5trueprefixmin with and without VBF, respectively) while reducing EI‐COV by 43.8%±16.6%. For 8‐phase acquisitions, VBF reduced acquisition time by 1.9±1.6trueprefixmin and EI‐COVs by 38.8%±25.7% despite breathing rate remaining similar (11.1±3.8 breaths/min with vs. 10.5±2.9 without). Using VBF yielded higher duty cycles than unguided free breathing (34.4%±5.8% vs. 28.1%±6.6%, respectively). Image grading showed that out of 40 paired evaluations, 20 cases had equivalent and 17 had improved image quality scores with VBF, particularly for mid‐exhale and EI. Increased liver excursion was observed with VBF, where superior–inferior, anterior–posterior, and left–right EE‐EI displacements were 14.1±5.8, 4.9±2.1, and 1.5±1.0 mm, respectively, with VBF compared to 11.9±4.5, 3.7±2.1, and 1.2±1.4 mm without. Incorporating VBF into 4D MRI substantially reduced acquisition time, breathing irregularity, and image artifacts. However, differences in excursion were observed, thus implementation will be required throughout the RT workflow.PACS number(s): 87.55.‐x, 87.61.‐c, 87.19.xj