The efficiency of magnetic resonance imaging in detection of diaphragmatic injury in left thoracoabdominal penetrating injuries

Aim Traumatic injuries of the diaphragm usually occur as a result of penetrating or blunt injury to the thoracoabdominal area. As a result of increased prevalence of stab and gunshot wounds, there is an increase in the incidence of diaphragm injuries. Traumatic diaphragm rupture can be asymptomatic in its early course. Later on, organ herniation through the lacerated diaphragm causes symptoms. These symptoms largely occur because of incarceration/strangulation of the herniated stomach or intestines, which is associated with mortality. Early diagnosis and repair of diaphragmatic injuries is of vital importance. Organ herniation due to penetrating thoracoabdominal injuries are mostly seen in left-sided injuries. In right-sided diaphragm injuries herniation is seen less commonly since liver plays a protective role. A traumatic diaphragmatic rupture is difficult to diagnose by physical examination alone. Unless an obvious finding exists (organ herniation etc.), a diagnosis is difficult to establish through imagings done in emergency settings alone . The gold standard in diagnosis is the diagnostic surgical exploration. The aim of our study is to compare the performance of Magnetic Resonance Imaging (MRI) in diagnosing diaphragm injuries in left-sided thoracoabdominal penetrating stab wounds, with Computed Tomography (CT) and the gold standard diagnostic laparoscopy/laparotomy. If the sensitivity and specificity of MRI is found to be high, the surgical intervention rates may decrease. As a result, rates of negative laparoscopy/laparotomy and related complications as well as hospital stay lengths may be lowered. Material and Methods Patients that presented to Istanbul Faculty of Medicine Emergency Surgery Department with left-sided thoracoabdominal penetrating stab wounds between November 2017 and December 2020 were selected. Those who required immediate surgery, did not have an MRI or could not be operated on were excluded from the study. The pre-operative MR and CT images of patients who went through diagnostic laparoscopy/laparotomy were retrospectively evaluated by a radiologist who have blinded to the surgical findings. The MRI findings were compared with the surgical and CT findings. Results A total of 43 patients (41 male, mean age 31, range 15-57) were included in the study. A lateral injury was the most common finding at physical examination. A diaphragmatic injury was confirmed in 13 (%30) patients during surgical exploration. 11 (%84) of the diaphragmatic injuries were repaired laparoscopically while 2 (%15) were repaired thoracoscopically. MRI images were found to be consistent with a diaphragmatic injury in 13 patients (32%), one of whom had no injury identified with surgical exploration. CT images were consistent with a diaphragmatic injury in 13 (%30) patients, one of whom had no injury visible during surgical exploration. One patient had a false negative CT scan while surgical exploration did identify a diphragmatic injury. According to these data, MRI had a sensitivity of 100%, specificity of 94%, positive predictive value (PPV) of 86% and a negative predictive value (NPV) of 100%. The CT scan had a sensitivity of 88% and specificity of 95%. Mean hospital stay length was 6 (range 1-30) days. Conclusion In this study, MRI was found to have a high specificity and sensitivity in detection of diaphragmatic injuries. MR imaging by itself was found to be adequate for the evaluation of the diaphragmatic muscle. The number of negative laparoscopy/laparotomies can be lowered by performing surgeries on cases where the MRI is positive or suspicious for diaphragmatic injury. These data need to be verified by larger case series.