The tarsometatarsal, or Lisfranc, joint complex provides stability to the midfoot and forefoot through intricate osseous relationships between the distal tarsal bones and metatarsal bases and their connections with stabilizing ligamentous support structures. Lisfranc joint injuries are relatively uncommon, and their imaging findings can be subtle. These injuries have typically been divided into high-impact fracture-displacements, which are often seen after motor vehicle collisions, and low-impact midfoot sprains, which are more commonly seen in athletes. The injury mechanism often influences the imaging findings, and classification systems based primarily on imaging features have been developed to help diagnose and treat these injuries. Patients may have significant regional swelling and pain that prevent thorough physical examination or may have other more critical injuries at initial posttrauma evaluation. These factors may cause diagnostic delays and lead to subsequent morbidities, such as midfoot instability, deformity, and debilitating osteoarthritis. Missed Lisfranc ligament injuries are among the most common causes of litigation against radiologists and emergency department physicians. Radiologists must understand the pathophysiology of these injuries and the patterns of imaging findings seen at conventional radiography, computed tomography, and magnetic resonance imaging to improve injury detection and obtain additional information for referring physicians that may affect the selection of the injury classification system, treatment, and prognosis.

Monitoring post cardiac transplant (TX) status relies on frequent invasive techniques such as endomyocardial biopsies and right heart cardiac catheterization. The aim of this study was to noninvasively evaluate regional myocardial structure, function, and dyssynchrony in TX patients. Myocardial T2-mapping and myocardial velocity mapping of the left ventricle (basal, midventricular, and apical short-axis locations) was applied in 10 patients after cardiac transplantation (49 ± 13 years, n = 2 with signs of mild rejection, time between TX and MRI = 1-64 months) and compared to healthy controls (n = 20 for myocardial velocity mapping and n = 14 for T2). Segmental analysis based on the 16-segment American Heart Association model revealed increased T2 (P = 0.0003) and significant (P < 0.0001) reductions in systolic and diastolic radial and long-axis peak myocardial velocities in TX patients without signs of rejection compared to controls. Multiple comparisons of individual left ventricular segments demonstrated reductions of long-axis peak velocities in 50% of segments (P < 0.001) while segmental T2 values were not significantly different. Systolic radial as well as diastolic radial and long-axis dyssynchrony were significantly (P < 0.04) increased in TX patients indicating less coordinated contraction, expansion, and lengthening. Correlation analysis revealed moderate but significant (P < 0.010) inverse relationships between myocardial T2 and long-axis peak velocities suggesting a structure-function relationship between altered T2 and myocardial function.

Purpose To evaluate two nonenhanced MRA methods: quiescent-interval single-shot (QISS) and Native SPACE (NATIVE= Non-contrast Angiography of the Arteries and Veins; SPACE = Sampling Perfection with Application Optimized Contrast by using different flip angle Evolution), using contrast-enhanced MR angiography (CEMRA) as a reference standard. Materials and Methods 20 patients (14 male, mean 69.3 years old) referred for lower extremity MRA were recruited in a HIPAA-compliant prospective study. QISS and Native SPACE of the lower extremities were performed at 1.5T with a hybrid dual-injection contrast-enhanced MRA as reference. Image quality and stenosis severity were assessed in segments by two blinded radiologists. Methods were compared with logistic regression for correlated data for diagnostic accuracy. Results Of 496 arterial segments, 24 were considered non-diagnostic on the Native SPACE images. There were no QISS or CEMRA imaging segments considered to be non-diagnostic. Image quality was significantly higher for QISS than for Native SPACE. QISS stenosis sensitivity (84.9%) was not significantly different from Native SPACE (87.3%). QISS had better specificity (95.6%) than Native SPACE (87.0%), p=0.0041. In comparison with QISS, Native SPACE proved less robust for imaging of the abdominal and pelvic segments. Conclusion Native SPACE and QISS were sensitive for hemodynamically significant stenosis in this pilot study. QISS NEMRA demonstrated superior specificity and image quality, and was more robust in the abdominal and pelvic regions.

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