1350952 - Pediatric Cardiac Trauma: Obtaining Optimal Imaging

An 8-yr-old female presented to the E.R. after being kicked in the chest by a horse. Following the trauma, she lost consciousness, requiring CPR for 5-10 minutes with return of spontaneous circulation. In the E.R, CT demonstrated pulmonary contusions and pleural effusions. Lab work noted elevated troponin. The child had difficulty breathing and chest pain.

An echo was obtained revealing a small posterior muscular VSD, no pericardial effusion, and normal biventricular systolic function. There was no prior history of auscultated heart murmur. Cardiac MRI was performed to assess the nature of the VSD and whether it could be traumatic in etiology.

Methods:

Based on the clinical history, the imaging protocol utilized techniques to assess for cardiac inflammation. Cine balanced steady state free precession (bSSFP), T2-weighted black blood fat saturated, T1 and T2 short axis maps, phase-sensitive inversion recovery (PSIR), and whole heart 3D bSSFP imaging were obtained using free breathing techniques.
Pain medication was given for patient discomfort, and patient anxiety was alleviated through non-pharmacologic techniques. Due to the patient’s age and pain, specific attention was given to accelerate the duration of the scan. Sense imaging was used for the cine and PSIR imaging, using a sense factor range of 2-2.4. Compressed sense imaging was utilized for the 3D bSSFP imaging, using a factor of 3.8. The phase encoding field of view was reduced. To compensate for breathing motion artifact, an extra signal average (NSA) was added to the cines and PSIR imaging, the cine scans were gated, and a respiratory navigator was used with the 3D bSSFP and T2-weighted black blood fat saturated imaging.

Results:

On cine imaging, a posterior muscular VSD was identified, measuring 7x4mm with paradoxical inferior right ventricular wall motion.  The T1 and T2 values were locally elevated within the ventricular septum, near the VSD.  There was possible focal late gadolinium enhancement at the inferior border of VSD.  Due to these findings, the VSD was thought to be of traumatic etiology.

Conclusion:

Imaging pediatric patients with cardiac contusion by CMR techniques can be challenging due to pain and anxiety from the recent trauma.  Maximizing patient comfort, effective pain management, and age-appropriate teaching can improve the success of the scan.  In addition, it is important to have a plan for the order of sequences by importance to adequately answer the clinical question, in the event the study needs to be truncated.  When there may be limited window of time for acquisition due to patient pain/anxiety, utilizing sense and compressed sense imaging and reducing the phase field of view are helpful options to reducing the time of the scan. Using respiratory navigators and adding NSA can reduce breathing artifact. The combination of myocardial tissue characterization and cine imaging allowed for effective diagnosis of a traumatic VSD created by a horse kick to the child’s chest.