Background: Computed tomography (CT) and spirometry are the current standard methods for assessing lung anatomy and pulmonary ventilation, respectively. However, CT provides limited ventilation information and spirometry only provides global measures of lung ventilation. Thus, a method that can enable simultaneous examination of lung anatomy and ventilation is of clinical interest. Purpose: To develop and test a 4D respiratory-resolved sparse lung MRI (XD-UTE: eXtra-Dimensional Ultrashort TE imaging) approach for simultaneous evaluation of lung anatomy and pulmonary ventilation. Study Type: Prospective. Population: In all, 23 subjects (11 volunteers and 12 patients, mean age = 63.6 ± 8.4). Field Strength/Sequence: 3T MR; a prototype 3D golden-angle radial UTE sequence, a Cartesian breath-hold volumetricinterpolated examination (BH-VIBE) sequence. Assessment: All subjects were scanned using the 3D golden-angle radial UTE sequence during normal breathing. Ten subjects underwent an additional scan during alternating normal and deep breathing. Respiratory-motion-resolved sparse reconstruction was performed for all the acquired data to generate dynamic normal-breathing or deep-breathing image series. For comparison, BH-VIBE was performed in 12 subjects. Lung images were visually scored by three experienced chest radiologists and were analyzed by two observers who segmented the left and right lung to derive ventilation parameters in comparison with spirometry. Statistical Tests: Nonparametric paired two-tailed Wilcoxon signed-rank test; intraclass correlation coefficient, Pearson correlation coefficient. Results: XD-UTE achieved significantly improved image quality compared both with Cartesian BH-VIBE and radial reconstruction without motion compensation (P < 0.05). The global ventilation parameters (a sum of the left and right lung measures) were in good correlation with spirometry in the same subjects (correlation coefficient = 0.724). There were excellent correlations between the results obtained by two observers (intraclass correlation coefficient ranged from 0.8855-0.9995).View this article online at wileyonlinelibrary.com.

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Diaphragmatic injury is an uncommon but clinically important entity in the setting of trauma. Computed tomography (CT) is widely used to evaluate hemodynamically stable trauma patients. While prior studies have identified CT signs of diaphragm injury in blunt or penetrating trauma, no study has directly compared signs across these two types of injuries. We identified patients with surgically proven diaphragm injuries who underwent CT at presentation. Three reviewers examined each for 12 signs of diaphragm injury, as well as for an overall impression of diaphragm injury. We reviewed a total of 84 patients (37 % blunt trauma, 63 % penetrating). The initial interpreting radiologists discovered 77 % of blunt and 47 % of penetrating injuries (p = 0.01). We found that the majority of signs of diaphragmatic injury were split between those common in blunt trauma and those common in penetrating trauma, with minimal overlap. The presence of at least one blunt injury sign has 90 % sensitivity for diaphragm injury in blunt trauma; the presence of a wound tract traversing the diaphragm has 92 % sensitivity in penetrating trauma. Inter-observer reliability of these signs is also high (κ > 0.65). Penetrating diaphragm injuries present a different spectrum of imaging findings from those in blunt trauma and are underdiagnosed at CT; looking for a wound tract traversing the diaphragm is highly sensitive for diaphragm injury in these cases. Signs of organ or diaphragm fragment displacement are sensitive for blunt diaphragm injuries, consistent with these injuries being caused by increased intra-abdominal pressure.

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