CT in head trauma: a review

Use of MRI in patients with severe diffuse traumatic brain injury: A matched National Trauma Data Bank analysis

OBJECTIVE

Magnetic resonance imaging (MRI) is increasingly used to evaluate patients with diffuse traumatic brain injury (dTBI). However, the utility of early MRI is understudied. We hypothesize that early MRI patients will have increased length of stay but no changes in intracranial pressure (ICP) management or disposition.

METHODS

The 2019 National Trauma Data Bank was queried for patients with dTBI and Glasgow Coma Scale score ≤8. Extra-axial and focal intra-axial hemorrhages were excluded. Clinical characteristics were controlled for. Patients with and without MRI were compared for ICP management, outcome, mortality, and disposition. A propensity score matching algorithm was used to create a 1:1 match cohort.

RESULTS

In 2568 patients, MRI was less common in severe dTBI patients with clear reasons for poor examination, including bilaterally unreactive pupils or midline shift. After matching, 501 patients who underwent MRI within 1 week were compared with 501 patients without MRI. Magnetic resonance imaging patients had longer intensive care unit stays (11.6 ± 9.6 vs. 13.4 ± 9.5, p < 0.01; 95% confidence interval [95% CI], -3.03 to -0.66). There was no difference between groups in ICP monitor (23.6% vs. 27.3%; p = 0.17; 95% CI, -0.09 to 0.02) or ventriculostomy placement (13.6% vs. 13.2%, p = 0.85; 95% CI, -0.04 to 0.05) or in withdrawal of care (15.0% vs. 18.6%, p = 0.12; 95% CI, -0.08 to 0.01). MRI patients were more likely to be discharged to inpatient rehabilitation (42.9% vs. 33.5%; p < 0.01; 95% CI, 0.03-0.15) but not to home (9.4% vs. 9.0%; p = 0.83; 95% CI, -0.03 to 0.04).

CONCLUSION

The decision to pursue early brain MRI may be driven by lack of obvious reasons for a patient's poor neurologic status. MRI patients had longer intensive care unit stays but no difference in rates of placement of ICP monitors or ventriculostomies or withdrawal of care. Further study is required to define the role of early MRI in dTBI patients.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Multi-organ segmentation of CT via convolutional neural network: impact of training setting and scanner manufacturer

Objective. Automated organ segmentation on CT images can enable the clinical use of advanced quantitative software devices, but model performance sensitivities must be understood before widespread adoption can occur. The goal of this study was to investigate performance differences between Convolutional Neural Networks (CNNs) trained to segment one (single-class) versus multiple (multi-class) organs, and between CNNs trained on scans from a single manufacturer versus multiple manufacturers.Methods. The multi-class CNN was trained on CT images obtained from 455 whole-body PET/CT scans (413 for training, 42 for testing) taken with Siemens, GE, and Phillips PET/CT scanners where 16 organs were segmented. The multi-class CNN was compared to 16 smaller single-class CNNs trained using the same data, but with segmentations of only one organ per model. In addition, CNNs trained on Siemens-only (N = 186) and GE-only (N = 219) scans (manufacturer-specific) were compared with CNNs trained on data from both Siemens and GE scanners (manufacturer-mixed). Segmentation performance was quantified using five performance metrics, including the Dice Similarity Coefficient (DSC).Results. The multi-class CNN performed well compared to previous studies, even in organs usually considered difficult auto-segmentation targets (e.g., pancreas, bowel). Segmentations from the multi-class CNN were significantly superior to those from smaller single-class CNNs in most organs, and the 16 single-class models took, on average, six times longer to segment all 16 organs compared to the single multi-class model. The manufacturer-mixed approach achieved minimally higher performance over the manufacturer-specific approach.Significance. A CNN trained on contours of multiple organs and CT data from multiple manufacturers yielded high-quality segmentations. Such a model is an essential enabler of image processing in a software device that quantifies and analyzes such data to determine a patient's treatment response. To date, this activity of whole organ segmentation has not been adopted due to the intense manual workload and time required.

Revised indications for head CT in elderly patients with minor traumatic injuries: A retrospective analysis

PURPOSE

The purpose of this study was to assess the performance of a decision-tree for head-CT indication in elderly patients presenting minor traumatic injuries MATERIALS AND METHODS: A single-centre retrospective study was performed and analyses were based on emergency CT scans of all patients aged 65 and over who experienced minor head trauma due to falls. The primary judgement criteria was the diagnosis of a traumatic intracranial haemorrhagic lesion (tICH) depicted on the CT scan. Focal neurological deficit and history of tICH on a previous CT scan were used to create the decision-tree.

RESULTS

A total of 1001 patients were included. Ninety-five (9.5%) had tICH on the CT scan. Of these patients, 42 (46.1%) had an abnormal Glasgow Coma Scale, 30 (31.6%) a focal neurological deficit and 13 (13.7%) a history of tICH on a previous CT scan. The presence of at least one of these 3 risk factors was associated with the occurrence of tICH (p <0.001). The decision-tree developed from these risk factors allowed the appropriate classification of 63 of 95 patients (66.3%) with tICH. Undetected haemorrhagic lesions in patients with no clinical severity criteria evolved favourably. The decision-tree correctly identified 97% of patients without any tICH on the CT.

CONCLUSION

Systematic head CT for elderly patients presenting minor head trauma could be irrelevant. A decision-tree based on objective clinical severity criteria for the indication of head CT could detect the majority of tICH requiring surgical intervention. Prospective randomized studies are mandatory to confirm these hypotheses.

Model-based reconstruction algorithm in the detection of acute trauma-related lesions in brain CT examinations

BACKGROUND AND PURPOSE

To evaluate the added value of a model-based reconstruction algorithm in the assessment of acute traumatic brain lesions in emergency non-enhanced computed tomography, in comparison with a standard hybrid iterative reconstruction approach.

MATERIALS AND METHODS

We retrospectively evaluated a total of 350 patients who underwent a 256-row non-enhanced computed tomography scan at the emergency department for brain trauma. Images were reconstructed both with hybrid and model-based iterative algorithm. Two radiologists, blinded to clinical data, recorded the presence, nature, number, and location of acute findings. Subjective image quality was performed using a 4-point scale. Objective image quality was determined by computing the signal-to-noise ratio and contrast-to-noise ratio. The agreement between the two readers was evaluated using k-statistics.

RESULTS

A subjective image quality analysis using model-based iterative reconstruction gave a higher detection rate of acute trauma-related lesions in comparison to hybrid iterative reconstruction (extradural haematomas 116 vs. 68, subdural haemorrhages 162 vs. 98, subarachnoid haemorrhages 118 vs. 78, parenchymal haemorrhages 94 vs. 64, contusive lesions 36 vs. 28, diffuse axonal injuries 75 vs. 31; all P<0.001). Inter-observer agreement was moderate to excellent in evaluating all injuries (extradural haematomas k=0.79, subdural haemorrhages k=0.82, subarachnoid haemorrhages k=0.91, parenchymal haemorrhages k=0.98, contusive lesions k=0.88, diffuse axonal injuries k=0.70). Quantitatively, the mean standard deviation of the thalamus on model-based iterative reconstruction images was lower in comparison to hybrid iterative one (2.12 ± 0.92 vsa 3.52 ± 1.10; P=0.030) while the contrast-to-noise ratio and signal-to-noise ratio were significantly higher (contrast-to-noise ratio 3.06 ± 0.55 vs. 1.55 ± 0.68, signal-to-noise ratio 14.51 ± 1.78 vs. 8.62 ± 1.88; P<0.0001). Median subjective image quality values for model-based iterative reconstruction were significantly higher (P=0.003).

CONCLUSION

Model-based iterative reconstruction, offering a higher image quality at a thinner slice, allowed the identification of a higher number of acute traumatic lesions than hybrid iterative reconstruction, with a significant reduction of noise.

Clinical Outcome and Management for Geriatric Traumatic Injury: Analysis of 2688 Cases in the Emergency Department of a Teaching Hospital in Taiwan

Geriatric traumatic injuries in emergency departments are frequent and associated with higher mortality rates and catastrophic functional outcomes. Several prediction scores have been established to manage traumatic patients, including the shock index (SI), revised trauma score (RTS), injury severity score (ISS), trauma injury severity score (TRISS), and new injury severity score (NISS). However, it was necessary to investigate the effectiveness and efficiency of care for the geriatric traumatic population. In addition, image studies such as computed tomography and magnetic resonance imaging play an important role in early diagnosis and timely intervention. However, few studies focus on this aspect. The association between the benefit of carrying out more image studies and clinical outcomes remains unclear. In this study, we included a total of 2688 traumatic patients and analyzed the clinical outcomes and predicting factors in terms of geriatric trauma via pre-hospital and in-hospital analysis. Our evaluation revealed that a shock index ≥1 may be not a strong predictor of geriatric trauma due to the poor physical response in the aging population. This should be modified in geriatric patients. Other systems, like RTS, ISS, TRISS, and NISS, were significant in terms of predicting the clinical outcome.

cGMP and cAMP cause pulmonary vasoconstriction in the presence of hemolysate

We recently reported that addition of a small amount of hemolysate to the salt solution that perfused isolated rat lungs hypersensitized the vasculature to subsequent additions of ANG II or exposure to hypoxia, and addition of NO gas (. NO) to the perfusate that contained hemolysate caused a strong vasoconstrictor rather than a vasodilator response. In the present study, we demonstrate that CO and the secondary messengers cGMP and cAMP (usually associated with vasodilation) exert similar effects in hemolysate-perfused lungs. Analogs of the cyclic nucleotides cGMP or cAMP (8-bromo-cGMP and dibutyryl-cAMP, respectively) caused profound vasoconstriction in the isolated rat lung perfused with a salt solution that contained hemolysate. The cGMP- or cAMP-analog-induced vasoconstriction was inhibited by chemically dissimilar Ca2+ antagonists, by the protein phosphatase inhibitor okadaic acid, and, to a lesser degree, by protein kinase inhibitor H-7. Antiphosphothreonine immunoblotting demonstrated that lungs perfused with hemolysate exhibit increased phosphorylation of several proteins. These data indicate that, in the presence of hemolysate, pulmonary vasculature responds to nominally vasodilatory stimuli, including analogs of cGMP and cAMP, with vasoconstriction rather than vasodilation. The importance of our finding is the paradoxical nature of the response to (analogs of) cyclic nucleotides because, to our knowledge, cyclic nucleotide-induced vasoconstriction has not been previously reported.

Cerebral trauma and alcohol abuse

We report results of clinical examinations, computed tomography, quantitative electroencephalography (QEEG), and cerebral blood flow measurements performed on a series of 56 consecutive brain injury patients including 15 alcohol abusers and 41 non-alcoholic subjects. Greater volumes of intracranial haemorrhage were noted in the alcoholics for a similar severity of injury and local brain atrophy became more pronounced in them during a follow-up of 1 year. After this time, the third ventricle width, distance between frontal horns, the sum of lateral ventricle dimensions and cortical sulci were all markedly larger in the alcoholics. The QEEG results also indicated a weaker improvement in the alcoholics. The cerebral blood flow at the site of the injury was initially slow in the alcoholics when compared to the contralateral region of the other hemisphere, although these differences disappeared during the follow-up. Permanent occupational disability was also found to be associated with pretraumatic alcohol abuse. The findings indicate that ethanol abuse is not only commonly associated with cerebral trauma but is also a risk factor for a more severe brain damage following the injury.

Craniocerebral trauma in the child abuse syndrome: radiological observations

Experience with craniocerebral trauma in 712 physically abused children is reviewed. Ninety-three (13%) had evidence of head trauma (cranial and/or intracranial). Seventy-seven of these patients had computed tomography (CT) of the head, and 47 had CT evidence of intracranial injury. Extracerebral fluid collections, predominantly convexity subdural hemorrhage, were the most common acute intracranial lesions. Concurrent intracranial and skeletal trauma (cranial and/or extracranial) was present in 33 of the 47 patients (70%) with intracranial injury. A high incidence of skull fractures (45%) in those children with intracranial lesions suggest a significant role for impact head injuries ("battering") in the pathogenesis of craniocerebral trauma in the child abuse syndrome. Greater emphasis on CT examination in evaluation of the abuse infant and child is recommended.