Kathirkamanathan Shanmuganathan

Helical Computed tomography of bowel and mesenteric injuries

BACKGROUND The role of computed tomography in diagnosing hollow viscus injury after blunt abdominal trauma remains controversial, with previous studies reporting both high accuracy and poor results. This study was performed to determine the diagnostic accuracy of helical computed tomography in detecting bowel and mesenteric injuries after blunt abdominal trauma in a large cohort of patients. METHODS One hundred fifty patients were admitted to our Level I trauma center over a 4-year period with computed tomographic (CT) scan or surgical diagnosis of bowel or mesenteric injury. CT scan findings were retrospectively graded as negative, nonsurgical, or surgical bowel or mesenteric injury. The CT scan diagnosis was then compared with surgical findings, which were also graded as negative, nonsurgical, or surgical. RESULTS Computed tomography had an overall sensitivity of 94% in detecting bowel injury and 96% in detecting mesenteric injury. Surgical bowel cases were correctly differentiated in 64 of 74 cases (86%), and surgical mesenteric cases were correctly differentiated from nonsurgical in 57 of 76 cases (75%). CONCLUSION Helical CT scanning is very accurate in detecting bowel and mesenteric injuries, as well as in determining the need for surgical exploration in bowel injuries. However, it is less accurate in predicting the need for surgical exploration in mesenteric injuries alone.

Diffusion Tensor MR Imaging in Cervical Spine Trauma

BACKGROUND AND PURPOSE: Our aim was to investigate the extent and severity of changes in spinal cord diffusion tensor imaging (DTI) parameters in patients with cervical cord injury. MATERIALS AND METHODS: DTI was performed in 20 symptomatic patients (mean, 45.7 ± 17.7 years of age; 2 women, 18 men) with cervical spine trauma and 8 volunteers (mean, 34.2 ± 10.7 years of age; 6 men, 2 women). The whole cord and regional apparent diffusion coefficient (ADC), fractional anisotropy (FA), relative anisotropy (RA), and volume ratio (VR) of patients and volunteers were compared. DTI parameters were calculated in 16 patients. MR imaging demonstrated hemorrhagic cord contusions (n = 6), nonhemorrhagic cord contusions (n = 4), and soft-tissue injury (n = 6). Medical records were reviewed for extent of neurologic deficit. RESULTS: Regional ADC values differed significantly between upper and mid and upper and lower (both, P < .004) cervical cord sections. FA was significantly different between upper and lower sections (P < .03). Whole cord ADC values were significantly lower in patients than in volunteers (P < .0001). Whole spine FA was not significantly decreased in patients (P < .06). ADC and FA values were significantly decreased at injury sites when compared with volunteers (P < .031 and .0001, respectively). The greatest differences in whole cord ADC, FA, RA, and VR were in patients with hemorrhagic cord contusions compared with healthy volunteers (P < .0001, .003, .0005, and .008, respectively). CONCLUSION: DTI parameters are sensitive markers of cervical cord injury, with ADC showing the greatest sensitivity. Changes in DTI parameters are most marked at injury sites and reflect the severity of cord injury.

Diagnosis of Blunt Cerebrovascular Injuries with 16-MDCT: Accuracy of Whole-Body MDCT Compared with Neck MDCT Angiography

OBJECTIVE The objective of our study was to determine whether whole-body 16-MDCT and neck MDCT angiography (MDCTA) can be used to diagnose blunt cerebrovascular injuries with comparable accuracy using angiography as the reference standard. MATERIALS AND METHODS Retrospective review of radiology reports and prospective clinical observation identified 108 blunt trauma patients examined with either whole-body MDCT or neck MDCTA followed by angiography over a 23-month period. From this group, results from the retrospective interpretations of 77 whole-body MDCT and 48 neck MDCTA examinations were compared with the results extracted from angiography reports to estimate the accuracy of each protocol for detecting blunt cerebrovascular injuries. Fishers exact test was used to determine any significant difference in the results of those patients scanned with both protocols. RESULTS Angiography confirmed blunt cerebrovascular injury in 83 patients, with 25 (30%) showing multiple sites of injury. Most injuries were detected in cervical arterial segments. The respective sensitivities of whole-body MDCT and neck MDCTA were 69% (36/52) and 64% (16/25) for cervical internal carotid artery injuries, and specificities were 82% (58/71) and 94% (49/52). Respective sensitivities for cervical vertebral artery injuries were 74% (17/23) and 68% (13/19), and specificities were 91% (60/66) and 100% (40/40). In 17 patients scanned with both protocols, the results were not significantly different (carotid arteries, p = 1.00; vertebral arteries, p = 0.68). CONCLUSION Whole-body 16-MDCT and neck MDCTA can be used to diagnose blunt cerebrovascular injuries with comparable accuracy. Both show high specificities for cervical arterial injury. The sensitivity of whole-body 16-MDCT is sufficiently high to serve as an initial screening examination for blunt cerebrovascular injuries.

Imaging diagnosis of nonaortic thoracic injury.

Chest radiographs remain the initial imaging modality to rapidly screen patients with blunt chest trauma. Spiral CT is more sensitive and specific in diagnosing most thoracic pathology seen in blunt trauma patients. This article reviews the major clinical and radiologic findings that occur with blunt injuries to the chest, excluding mediastinal vascular injuries.

Evaluation of a Single-Pass Continuous Whole-Body 16-MDCT Protocol for Patients with Polytrauma

OBJECTIVE The purpose of this study was to compare a conventional multiregional MDCT protocol with two continuous single-pass whole-body MDCT protocols in imaging of patients with polytrauma. SUBJECTS AND METHODS Ninety patients with polytrauma underwent whole-body 16-MDCT with a conventional (n=30) or one of two single-pass (n=60) protocols. The conventional protocol included unenhanced scans of the head and cervical spine and contrast-enhanced helical scans (140 mL, 4 mL/s, 300 mg I/mL) of the thorax and abdomen. The single-pass protocols consisted of unenhanced scans of the head followed by one-sweep acquisition from the circle of Willis through the pubic symphysis with a biphasic (150 mL, 6 and 4 mL/s, 300 mg I/mL) or monophasic (110 mL, 4 mL/s, 400 mg I/mL) injection. Acquisition times and interval delays between head, chest, and abdominal scans were recorded. Contrast enhancement was measured in the aortic arch, liver, spleen, and kidney. Diagnostic image quality in the same areas was assessed on a 4-point scale. RESULTS Median acquisition times for the single-pass protocols were significantly shorter (-42.5%) than the acquisition time for the conventional protocol. No significant differences were found in mean enhancement values in the aorta, liver, spleen, and kidney for the three protocols. The image quality with both single-pass protocols was better than that with the conventional protocol in assessment of the mediastinum and cervical spine (p<0.05). There was no significant difference between the single-pass protocols. CONCLUSION Use of single-pass continuous whole-body MDCT protocols can significantly decrease examination time for patients with polytrauma and improve image quality compared with a conventional serial scan protocol. Monophasic injection with highly concentrated contrast medium can reduce injection flow rate and should therefore be preferred to a biphasic injection technique.

Correlation of Multidetector CT Findings with Splenic Arteriography and Surgery: Prospective Study in 392 Patients

BACKGROUND To determine the accuracy of contrast-enhanced multidetector CT (MDCT) in demonstrating splenic vascular injury based on results of splenic angiography and operation. STUDY DESIGN This institutional review board-approved study included 392 hemodynamically stable blunt trauma patients whose admission MDCTs demonstrated splenic injury. Images were assessed for parenchymal injury grade, hemoperitoneum volume, and evidence of bleeding and nonbleeding splenic vascular injury. Splenic arteriography was performed for high splenic injury grade and splenic vascular injury. Medical records were reviewed to determine arteriographic interpretation, surgery indications and findings, outcomes, and demographics. Sensitivity, specificity, predictive values, and accuracy of MDCT in detecting vascular injury were calculated based on results of arteriography and operation. RESULTS Splenic vascular injury was seen in 22% of patients (86 of 392) on MDCT. Presence of a vascular injury correlated with the CT-based parenchymal splenic injury grade (p < 0.0001). Active splenic bleeding was associated with subsequent clinical deterioration (p < 0.0001). Overall, MDCT had a sensitivity of 76% (76 of 100); specificity of 90% (95 of 106); negative and positive predictive values of 80% (95 of 119) and 87% (76 of 87), respectively; and accuracy of 83% (171 of 206) in detecting vascular injury compared with reference standards. The success rate of nonoperative management was 96%. CONCLUSIONS MDCT provides valuable information to direct initial clinical management of patients with blunt splenic trauma by demonstrating both active bleeding and nonbleeding vascular injuries. Not all vascular injuries are detected on MDCT, and splenic angiography is still indicated for high-grade parenchymal injury.

Correlation of MR Diffusion Tensor Imaging Parameters with ASIA Motor Scores in Hemorrhagic and Nonhemorrhagic Acute Spinal Cord Injury

This study investigated correlations between American Spinal Injury Association (ASIA) clinical injury motor scores in patients with traumatic cervical cord injury and magnetic resonance (MR) diffusion tensor imaging (DTI) parameters. Conventional imaging and DTI were performed to evaluate 25 patients (age, 39.7±13.9 years; 4 women, 21 men) with blunt spinal cord injury and 11 volunteers (age, 31.5±10.7 years; 3 women, 8 men). Cord contusions were hemorrhagic (HC) in 13 and non-hemorrhagic (NHC) in 12 patients. The spinal cord was divided into three regions to account for spatial and pathological variation in DTI parameters. Comparisons of regional and injury site mean diffusivity (MD), fractional anisotropy (FA), radial diffusivity ( λ(⊥)), and longitudinal diffusivity ( λ(‖)) were made with control subjects. ASIA motor scores were correlated with DTI using linear regression analysis. HC and NHC patients showed significant reduction (p<0.001) in MD and λ(‖) in all three regions. At the injury site, significant decreases in FA and λ(‖) were seen for both injury groups (p<0.001). λ(⊥) values were significantly increased only for patients with NHC (p<0.05). Significant reduction in FA and λ(‖) (p<0.0001) was observed at the whole cord level between the injured (NH and NHC) and control groups. Within the NHC group, strong correlations were observed between ASIA motor scores and average MD, FA, λ(⊥), and λ(‖) at the injury site. However, no correlation was observed within the HC group between any of the DTI parameters and ASIA motor scores. DTI parameters reflect the severity of spinal cord injury and correlate well with ASIA motor scores in patients with NHC.

Predictors of outcome in acute traumatic central cord syndrome due to spinal stenosis.

OBJECT the objective of this study was to elucidate the relationship between admission demographic data, validated injury severity measures on imaging studies, and clinical indicators on the American Spinal Injury Association (ASIA) motor score, Functional Independence Measure (FIM), manual dexterity, and dysesthetic pain at least 12 months after surgery for acute traumatic central cord syndrome (ATCCS) due to spinal stenosis. METHODS over a 100-month period (January 2000 to April 2008), of 211 patients treated for ATCCS, 59 cases were due to spinal stenosis, and these patients underwent surgical decompression. Five of these patients died, 2 were lost to follow-up, 10 were not eligible for the study, and the remaining 42 were followed for at least 12 months. RESULTS in the cohort of 42 patients, mean age was 58.3 years, 83% of the patients were men, and 52.4% of the accidents were due to falls. Mean admission ASIA motor score was 63.8 (upper extremities score, 25.8 and lower extremities score, 39.8), the spinal cord was most frequently compressed at skeletal segments C3-4 and C4-5 (71%), mean midsagittal diameter at the point of maximum compression was 5.6 mm, maximum canal compromise (MCC) was 50.5%, maximum spinal cord compression was 16.5%, and length of parenchymal damage on T2-weighted MR imaging was 29.4 mm. Time after injury until surgery was within 24 hours in 9 patients, 24-48 hours in 10 patients, and more than 48 hours in 23 patients. At the 1-year follow-up, the mean ASIA motor score was 94.1 (upper extremities score, 45.7 and lower extremities score, 47.6), FIM was 111.1, manual dexterity was 64.4% of baseline, and pain level was 3.5. Stepwise regression analysis of 10 independent variables indicated significant relationships between ASIA motor score at follow-up and admission ASIA motor score (p = 0.003), MCC (p = 0.02), and midsagittal diameter (p = 0.02); FIM and admission ASIA motor score (p = 0.03), MCC (p = 0.02), and age (p = 0.02); manual dexterity and admission ASIA motor score (p = 0.0002) and length of parenchymal damage on T2-weighted MR imaging (p = 0.002); and pain level and age (p = 0.02) and length of parenchymal lesion on T2-weighted MR imaging (p = 0.04). CONCLUSIONS the main indicators of long-term ASIA motor score, FIM, manual dexterity, and dysesthetic pain were admission ASIA motor score, midsagittal diameter, MCC, length of parenchymal damage on T2-weighted MR imaging, and age, but different domains of outcome were determined by different predictors.

Predictors of pulmonary complications in blunt traumatic spinal cord injury

OBJECT Pulmonary complications are the most common acute systemic adverse events following spinal cord injury (SCI), and contribute to morbidity, mortality, and increased length of hospital stay (LOS). Identification of factors associated with pulmonary complications would be of value in prevention and acute care management. Predictors of pulmonary complications after SCI and their effect on neurological recovery were prospectively studied between 2005 and 2009 at the 9 hospitals in the North American Clinical Trials Network (NACTN). METHODS The authors sought to address 2 specific aims: 1) define and analyze the predictors of moderate and severe pulmonary complications following SCI; and 2) investigate whether pulmonary complications negatively affected the American Spinal Injury Association (ASIA) Impairment Scale conversion rate of patients with SCI. The NACTN registry of the demographic data, neurological findings, imaging studies, and acute hospitalization duration of patients with SCI was used to analyze the incidence and severity of pulmonary complications in 109 patients with early MR imaging and long-term follow-up (mean 9.5 months). Univariate and Bayesian logistic regression analyses were used to analyze the data. RESULTS In this study, 86 patients were male, and the mean age was 43 years. The causes of injury were motor vehicle accidents and falls in 80 patients. The SCI segmental level was in the cervical, thoracic, and conus medullaris regions in 87, 14, and 8 patients, respectively. Sixty-four patients were neurologically motor complete at the time of admission. The authors encountered 87 complications in 51 patients: ventilator-dependent respiratory failure (26); pneumonia (25); pleural effusion (17); acute lung injury (6); lobar collapse (4); pneumothorax (4); pulmonary embolism (2); hemothorax (2), and mucus plug (1). Univariate analysis indicated associations between pulmonary complications and younger age, sports injuries, ASIA Impairment Scale grade, ascending neurological level, and lesion length on the MRI studies at admission. Bayesian logistic regression indicated a significant relationship between pulmonary complications and ASIA Impairment Scale Grades A (p = 0.0002) and B (p = 0.04) at admission. Pulmonary complications did not affect long-term conversion of ASIA Impairment Scale grades. CONCLUSIONS The ASIA Impairment Scale grade was the fundamental clinical entity predicting pulmonary complications. Although pulmonary complications significantly increased LOS, they did not increase mortality rates and did not adversely affect the rate of conversion to a better ASIA Impairment Scale grade in patients with SCI. Maximum canal compromise, maximum spinal cord compression, and Acute Physiology and Chronic Health Evaluation-II score had no relationship to pulmonary complications.

Imaging of Traumatic Brain Injury

Imaging plays an important role in the management of patients with traumatic brain injury (TBI). Computed tomography (CT) is the first-line imaging technique allowing rapid detection of primary structural brain lesions that require surgical intervention. CT also detects various deleterious secondary insults allowing early medical and surgical management. Serial imaging is critical to identifying secondary injuries. MR imaging is indicated in patients with acute TBI when CT fails to explain neurologic findings. However, MR imaging is superior in patients with subacute and chronic TBI and also predicts neurocognitive outcome.