Update on New Imaging Techniques for Trauma

[Radiological diagnostics of lumbar spine fractures]

BACKGROUND

The lumbar spine forms the lowermost part of the mobile spinal column. Due to anatomical properties, the lumbar spine is highly flexible in the sagittal directions, thus, rendering it susceptible to both flexion and extension forces with the thoracolumbar junction being the most vulnerable part of it. To date, the modern thoracolumbar spine fracture classification is given by the AOSpine classification system based on the well-known Magerl classification of vertebral fracture morphology but now includes both neurological criteria and clinical modifiers, such as ankylosing spondylitis.

DIAGNOSTICS

Whereas plain radiography remains a mainstay in the diagnostic evaluation of low-energy trauma patients, computed tomography (CT) exhibits its unsurpassed power in polytrauma and plays a decisive role in all equivocal cases where the osseous situation is unclear. However, magnetic resonance imaging (MRI) is increasingly gaining importance for assessing both discoligamentous integrity and intraspinal condition. Both CT and MRI have direct input in classifying fractures according to the AOSpine classification.

RESULTS

Regarding fracture morphology, three main types (A-C) based on the stability are distinguished. C‑type spinal injuries are all considered unstable, irrespective of type and severity of vertebral malalignment. Injuries to the anterior and posterior ligamentous complex are also considered to interfere with stability (B-type injuries).

CONCLUSIONS

Special fracture patterns of the injured ankylosed and osteoporotic spine as well as of the pediatric lumbar spine are discussed. A survey is also given about several differential diagnoses (malignant fractures, anomalies, normal variants).

The role of diffusion tensor imaging as an objective tool for the assessment of motor function recovery after paraplegia in a naturally-occurring large animal model of spinal cord injury

Background

Traumatic spinal cord injury (SCI) results in sensory and motor function impairment and may cause a substantial social and economic burden. For the implementation of novel treatment strategies, parallel development of objective tools evaluating spinal cord (SC) integrity during motor function recovery (MFR) is needed. Diffusion tensor imaging (DTI) enables in vivo microstructural assessment of SCI.

Methods

In the current study, temporal evolvement of DTI metrics during MFR were examined; therefore, values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured in a population of 17 paraplegic dogs with naturally-occurring acute SCI showing MFR within 4 weeks after surgical decompression and compared to 6 control dogs. MRI scans were performed preoperatively and 12 weeks after MFR was observed. DTI metrics were obtained at the lesion epicentre and one SC segment cranially and caudally. Variance analyses were performed to compare values between evaluated localizations in affected dogs and controls and between time points. Correlations between DTI metrics and clinical scores at follow-up examinations were assessed.

Results

Before surgery, FA values at epicentres were higher than caudally (p = 0.0014) and control values (p = 0.0097); ADC values were lower in the epicentre compared to control values (p = 0.0035) and perilesional (p = 0.0448 cranially and p = 0.0433 caudally). In follow-up examinations, no significant differences could be found between DTI values from dogs showing MFR and control dogs. Lower ADC values at epicentres correlated with neurological deficits at follow-up examinations (r = − 0.705; p = 0.0023).

Conclusions

Findings suggest that a tendency to the return of DTI values to the physiological situation after surgical decompression accompanies MFR after SCI in paraplegic dogs. DTI may represent a useful and objective clinical tool for follow-up studies examining in vivo SC recovery in treatment studies.

Electronic supplementary material

The online version of this article (10.1186/s12967-018-1630-4) contains supplementary material, which is available to authorized users.