Does a "Cushion Effect" Really Exist? A Morphomic Analysis of Vulnerable Road Users with Serious Blunt Abdominal Injury

The Emerging Role and Clinical Applications of Morphomics in Diagnostic Imaging

Analytic morphomics refers to the accurate measurement of specific biological markers of human body composition in diagnostic medical imaging. The increasing prevalence of disease processes that alter body composition including obesity, cachexia, and sarcopenia has generated interest in specific targeted measurement of these metrics to possibly prevent or reduce negative health outcomes. Typical morphomic measurements include the area and density of muscle, bone, vascular calcification, visceral fat, and subcutaneous fat on a specific validated axial level in the patient's cross-sectional diagnostic imaging. A distinct advantage of these measurements is that they can be made retrospectively and opportunistically with pre-existing datasets. We provide a narrative review of the current state of art in morphomics, but also consider some potential future directions for this exciting field. Imaging based quantitative assessment of body composition has enormous potential across the breadth and scope of modern clinical practice. From risk stratification to treatment planning, and outcome assessment, all can be enhanced with the use of analytic morphomics. Moreover, it is likely that many new opportunities for personalized medicine will emerge as the field evolves. As radiologists, embracing analytic morphomics will enable us to contribute added value in the care of every patient.

Evaluation of the cushion effect in blunt abdominal trauma patients: A computerized analysis

BACKGROUND

Obesity may serve as a protective factor in blunt abdominal trauma (BAT) patients due to a "cushion effect". In this study, we aim to use computed tomography (CT) scans to measure abdominal adiposity and its correlation with injury severity in BAT patients.

METHODS

We conducted a retrospective analysis of male BAT patients who had undergone CT scans. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were manually measured and height-normalized for analysis at lumbar levels L2 and L3. Statistical methods were used to compare differences in adiposity between patients with and without severe abdominal injuries. For controls, we also compared adipose tissue in patients with and without severe trauma to the chest, where less fat typically accumulates.

RESULTS

We included 361 male participants and conducted a comparative analysis of their demographic and injury characteristics. Patients without severe abdominal injuries had significantly higher SAT and VAT indices at both L2 and L3 (p < 0.05). However, these measures showed no significant differences between patients with and without severe chest trauma. Solid organ injuries, particularly liver injuries, were associated with decreased SAT and VAT.

CONCLUSION

Increase abdominal adiposity was linked to lower abdominal injury severity and solid organ injuries, particularly liver injuries. In addition to conventional BMI for evaluating obesity, either subcutaneous or visceral adipose tissue over lumbar levels L2 and L3 can be used to assess the "cushion effect."

Obese adolescents have higher risk for femur fracture after motor vehicle collision

Background

Previous reports identified an association between obese adolescents (OAs) and lower extremity (LE) fractures after blunt trauma. However, the type of LE fracture remains unclear. We hypothesized that OAs presenting after motor vehicle collision (MVC) have a higher risk of severe LE fracture and will require a longer length of stay (LOS) and more support services upon discharge, compared to non-OAs.

Methods

The 2017-2019 Trauma Quality Improvement Program database was queried for adolescents (12-17-years-old) presenting after MVC. The primary outcome was LE fracture. A severe fracture was defined by abbreviated injury scale ≥3. OAs were defined by a body mass index (BMI) ≥30.

Results

From 22,610 MVCs, 3325 (14.7 %) included OAs. The rate of any LE fracture was higher for OAs (21.6 % vs. 18.8 %, p < 0.001). On subset analysis the only LE fracture at higher risk in OAs was a femur fracture (13 % vs. 9.1 %, p < 0.001). After adjusting for sex and age, the risk for severe LE fracture (OR 1.34, CI 1.18-1.53, p < 0.001) was higher for OAs. OAs with a femur fracture had a longer median LOS (5 vs. 4 days, p = 0.003) and were more likely discharged with additional support services including home-health or inpatient rehabilitation (30.6 % vs. 21.4 %, p < 0.001).

Conclusion

OAs sustaining MVCs have increased associated risk of femur fractures. OAs are more likely to have a higher-grade LE injury, experience a longer LOS, and require additional support services upon discharge. Future research is needed to determine if early disposition planning with social work assistance can help shorten LOS.

Cushioning the blow: role of perirenal fat in renal trauma injury severity

OBJECTIVES

To explore the association between perirenal fat thickness (PFT) and renal trauma grade. We hypothesise this association is related to a shock-absorbing effect of adiposity around the kidney.

PATIENTS AND METHODS

We identified all patients with renal trauma who arrived at the emergency department of a single trauma centre between 2014 and 2020. Radiology images were reviewed to measure the PFT around the uninjured kidney due to disrupted PFT around the traumatised kidney. Patients with no available images or penetrating trauma mechanism were excluded. Logistic regression was used to assess the relation between PFT and high-grade renal trauma (HGRT; defined as American Association for the Surgery of Trauma Renal Grade IV-V), adjusting for age, sex, and Injury Severity Scale (ISS).

RESULTS

A total of 150 patients with renal trauma were included. The median (interquartile range) age was 38.5 (26-52) years and 106 (70.7%) were males. The PFT ranged between 2.1 and 50.1 mm, and 31 (20.7%) had HGRT. Interestingly, PFT only mildly correlated with body mass index (BMI; Pearson correlation coefficient 0.42, P < 0.001). Those with HGRT had significantly lower PFT compared to those without HGRT (median 9.5 vs 11.9 mm, P = 0.047). In the multivariable analysis adjusting for age, sex, and ISS, increasing PFT was associated with decreased odds (odds ratio 0.91, 95% confidence interval 0.84-0.98; P = 0.015) of HGRT.

CONCLUSION

Increasing PFT is associated with lower risk of HGRT following blunt injury. These results support a protective cushion role of adiposity in renal trauma. Notably, PFT was not strongly correlated with BMI, underscoring limitations of BMI in measuring adiposity.