Centrifugal distribution of regional cerebral blood flow and its time course in traumatic intracerebral hematomas

Contusion Progression Following Traumatic Brain Injury: A Review of Clinical and Radiological Predictors, and Influence on Outcome

Secondary injuries remain an important cause of the morbidity and mortality associated with traumatic brain injury (TBI). Progression of cerebral contusions occurs in up to 75% of patients with TBI, and this contributes to subsequent clinical deterioration and requirement for surgical intervention. Despite this, the role of early clinical and radiological factors in predicting contusion progression remains relatively poorly defined due to studies investigating progression of all types of hemorrhagic injuries as a combined cohort. In this review, we summarize data from recent studies on factors which predict contusion progression, and the effect of contusion progression on clinical outcomes.

The extravasation of contrast as a predictor of cerebral hemorrhagic contusion expansion, poor neurological outcome and mortality after traumatic brain injury: A systematic review and meta-analysis

Background

The active extravasation of contrast on CT angiography (CTA) in primary intracerebral hemorrhages (ICH) is recognized as a predictive factor for ICH expansion, unfavorable outcomes and mortality. However, few studies have been conducted on the setting of traumatic brain injury (TBI).

Purpose

To perform a literature systematic review and meta-analysis of the association of contrast extravasation on cerebral hemorrhagic contusion expansion, neurological outcomes and mortality.

Data sources

The PubMed, Cochrane Library, Medline, Scielo, VHL and IBECS databases up to September 21, 2019, were searched for eligible studies.

Study selection

A total of 505 individual titles and abstracts were identified and screened. A total of 36 were selected for full text analysis, out of which 4 fulfilled all inclusion and exclusion criteria.

Data analysis

All 4 studies yielded point estimates suggestive of higher risk for hematoma expansion with contrast extravasation and the summary RR was 5.75 (95%CI 2.74–10.47, p<0.001). Contrast extravasation was also associated with worse neurological outcomes (RR 3.25, 95%CI 2.24–4.73, p<0.001) and higher mortality (RR 2.77, 95%CI 1.03–7.47, p = 0.04).

Data synthesis

This study is a Systematic Review and Meta-Analysis revealed the extravasation of contrast is a useful imaging sign to predict hematoma expansion, worse neurological outcomes and higher mortality.

Limitations

Only four articles were selected.

Conclusions

The extravasation of contrast in the setting of TBI is a useful imaging sign to predict hematoma expansion, worse neurological outcomes and higher mortality.

Perfusion Abnormalities are Frequently Detected by Early CT Perfusion and Predict Unfavourable Outcome Following Severe Traumatic Brain Injury

BACKGROUND

In patients with severe traumatic brain injury (TBI), early CT perfusion (CTP) provides additional information beyond the non-contrast CT (NCCT) and may alter clinical management. We hypothesized that this information may prognosticate functional outcome.

METHODS

Five-year prospective observational study was performed in a level-1 trauma centre on consecutive severe TBI patients. CTP (obtained in conjunction with first routine NCCT) was interpreted as: abnormal, area of altered perfusion more extensive than on NCCT, and the presence of ischaemia. Six months Glasgow Outcome Scale-Extended of four or less was considered an unfavourable outcome. Logistic regression analysis of CTP findings and core variables [preintubation Glasgow Coma Scale (GCS), Rotterdam score, base deficit, age] was conducted using Bayesian model averaging to identify the best predicting model for unfavourable outcome.

RESULTS

Fifty patients were investigated with CTP (one excluded for the absence of TBI) [male: 80%, median age: 35 (23-55), prehospital intubation: 7 (14.2%); median GCS: 5 (3-7); median injury severity score: 29 (20-36); median head and neck abbreviated injury scale: 4 (4-5); median days in ICU: 10 (5-15)]. Thirty (50.8%) patients had an unfavourable outcome. GCS was a moderate predictor of unfavourable outcome (AUC = 0.74), while CTP variables showed greater predictive ability (AUC for abnormal CTP = 0.92; AUC for area of altered perfusion more extensive than NCCT = 0.83; AUC for the presence of ischaemia = 0.81).

CONCLUSION

Following severe TBI, CTP performed at the time of the first follow-up NCCT, is a non-invasive and extremely valuable tool for early outcome prediction. The potential impact on management and its cost effectiveness deserves to be evaluated in large-scale studies.

LEVEL OF EVIDENCE III

Prospective study.

Risk Factors for Early Hemorrhagic Progression after Traumatic Brain Injury: A Focus on Lipid Profile

The purpose of this study was to identify the risk factors related to the hemorrhagic progression (HP) of brain contusion in patients after traumatic brain injury (TBI). Recently, many studies have reported abnormal lipid levels associated with hemorrhagic stroke. Unlike hemorrhage stroke, however, the lipid profiles in patients with TBI have not been examined. Therefore, we evaluated the risk factors of HP in patients with TBI and focused on lipid profiles. Fifty-six patients with TBI with mild to moderate injuries (Glasgow Coma Scale ≥9) who initially did not need surgical intervention were enrolled in this study. Patients underwent repeated computed tomography (CT) scans at 4 h and 24 h after injury. Magnetic resonance imaging (MRI) was performed 7 days after the initial injury. In each noncontrast CT scan, the hemorrhage volume was quantified using the ABC/2 technique. Clinical features, previous medical history, initial CT, and microbleeding on follow-up MRI were analyzed retrospectively. There were 31 (55%) patients in whom significant HP developed (volume >30%). Current smoking (p=0.034), higher initial systolic blood pressure (p=0.035), and lower triglyceride levels (p=0.039) were significantly associated with HP. Current smoking and a triglyceride (TG) level <150 mg/dL were the only statistically significant predictors of HP in the multivariate analysis (p=0.019, p=0.021, respectively). HP with TBI is common in patients who currently smoke and have lower TG levels (150 mg/dL). These patients should be monitored closely, and surgery may be considered before deterioration occurs.

Imaging of cerebral blood flow in patients with severe traumatic brain injury in the neurointensive care

Ischemia is a common and deleterious secondary injury following traumatic brain injury (TBI). A great challenge for the treatment of TBI patients in the neurointensive care unit (NICU) is to detect early signs of ischemia in order to prevent further advancement and deterioration of the brain tissue. Today, several imaging techniques are available to monitor cerebral blood flow (CBF) in the injured brain such as positron emission tomography (PET), single-photon emission computed tomography, xenon computed tomography (Xenon-CT), perfusion-weighted magnetic resonance imaging (MRI), and CT perfusion scan. An ideal imaging technique would enable continuous non-invasive measurement of blood flow and metabolism across the whole brain. Unfortunately, no current imaging method meets all these criteria. These techniques offer snapshots of the CBF. MRI may also provide some information about the metabolic state of the brain. PET provides images with high resolution and quantitative measurements of CBF and metabolism; however, it is a complex and costly method limited to few TBI centers. All of these methods except mobile Xenon-CT require transfer of TBI patients to the radiological department. Mobile Xenon-CT emerges as a feasible technique to monitor CBF in the NICU, with lower risk of adverse effects. Promising results have been demonstrated with Xenon-CT in predicting outcome in TBI patients. This review covers available imaging methods used to monitor CBF in patients with severe TBI.

Correlation of diffusion MRI findings with lesion progression in patients with traumatic intracerebral hemorrhage : diffusion MRI in traumatic intracerebral hemorrhages with progression

PURPOSE

The aim of this study is to evaluate the association between lesion progression and the ischemic or edematous area that can develop around the hemorrhage in intraparenchymal hemorrhagic lesions originating after head trauma.

METHODS

Thirty patients with intracerebral hemorrhage due to head trauma of a mild or intermediate degree were evaluated in this study. Brain diffusion MRI examinations were performed in the first 6 h after trauma in all patients. In addition, a computerized cranial tomography (CCT) was performed upon admission (in the first hour), and at 24 and 48 h after admission. Patients with or without progression of the lesion were compared.

RESULTS

The increase in the risk of progression of the lesion in patients with an ischemia/hemorrhage rate > 2 identified in the diffusion MRIs by evaluation of the hemorrhagic and the surrounding ischemic area, obtained in the first 6 h after trauma was found to be statistically significant. The possibility of progression was found to be very low when this rate was less than two.

CONCLUSIONS

As a result of the study, the ischemic area was found to be proportionally larger in patients with progression compared to nonprogressing patients with traumatic intracerebral hemorrhage. The ischemia/hemorrhage rate in the diffusion MRI is thought to be an important parameter, beneficial to identify the risk of lesion progression.

Early parenchymal contrast extravasation predicts subsequent hemorrhage progression, clinical deterioration, and need for surgery in patients with traumatic cerebral contusion

BACKGROUND

This study aimed to identify early radiologic signs that are predictive of hemorrhage progression and clinical deterioration in patients with traumatic cerebral contusion. We hypothesized that contrast extravasation (CE) and blood-brain barrier disruption might be associated with hemorrhage progression, brain edema, and clinical deterioration in these patients.

METHODS

Twenty-two patients with traumatic cerebral contusion (diagnosed on initial noncontrast head computed tomography [CT]) who initially did not require surgical intervention were enrolled in this study. Contrast-enhanced and perfusion CT scans were performed within 6 hours of injury, and follow-up noncontrast CT scans were performed at 24 hours and 72 hours.

RESULTS

In each noncontrast CT scan, the volumes of the contusion hemorrhage and edema were calculated using computerized planimetric techniques. The initial Glasgow Coma Scale, hemorrhage progression, clinical deterioration, and the need for subsequent surgery were recorded. The early radiologic findings were compared with these parameters and functional outcome at 6 months to identify predictive radiologic signs. CE was present in 9 of 22 patients (41%) and was highly associated with hemorrhage progression (p < 0.05), clinical deterioration (p < 0.01), and need for subsequent surgery (p < 0.01). In addition, patients with CE had a greater volume of edema at 24 hours (p < 0.01) and 72 hours (p < 0.01) than those who did not have CE. However, CE was not found to be associated with poor outcome.

CONCLUSIONS

Early parenchymal CE is associated with hemorrhage progression, cerebral edema, clinical deterioration, and need for subsequent surgery. These patients should be monitored closely, and early surgery may be needed if deterioration occurs. Further elucidation of the pathophysiology is needed to formulate effective treatment for these high-risk patients.

Common data elements in radiologic imaging of traumatic brain injury

Traumatic brain injury (TBI) has a poorly understood pathology. Patients suffer from a variety of physical and cognitive effects that worsen as the type of trauma worsens. Some noninvasive insights into the pathophysiology of TBI are possible using magnetic resonance imaging (MRI), computed tomography (CT), and many other forms of imaging as well. A recent workshop was convened to evaluate the common data elements (CDEs) that cut across the imaging field and given the charge to review the contributions of the various imaging modalities to TBI and to prepare an overview of the various clinical manifestations of TBI and their interpretation. Technical details regarding state-of-the-art protocols for both MRI and CT are also presented with the hope of guiding current and future research efforts as to what is possible in the field. Stress was also placed on the potential to create a database of CDEs as a means to best record information from a given patient from the reading of the images.

Physiological and histopathological responses following closed rotational head injury depend on direction of head motion

Rotational inertial forces are thought to be the underlying mechanism for most severe brain injuries. However, little is known about the effect of head rotation direction on injury outcomes, particularly in the pediatric population. Neonatal piglets were subjected to a single non-impact head rotation in the horizontal, coronal, or sagittal direction, and physiological and histopathological responses were observed. Sagittal rotation produced the longest duration of unconsciousness, highest incidence of apnea, and largest intracranial pressure increase, while coronal rotation produced little change, and horizontal rotation produced intermediate and variable derangements. Significant cerebral blood flow reductions were observed following sagittal but not coronal or horizontal injury compared to sham. Subarachnoid hemorrhage, ischemia, and brainstem pathology were observed in the sagittal and horizontal groups but not in a single coronal animal. Significant axonal injury occurred following both horizontal and sagittal rotations. For both groups, the distribution of injury was greater in the frontal and parietotemporal lobes than in the occipital lobes, frequently occurred in the absence of ischemia, and did not correlate with regional cerebral blood flow reductions. We postulate that these direction-dependent differences in injury outcomes are due to differences in tissue mechanical loading produced during head rotation.

Evolution of traumatic intracerebral hemorrhage captured with CT imaging: report of a case and the role of serial CT scans

Delayed enlargement of a traumatic cerebral contusion can occur subsequent to an initial CT scan, and this can lead to neurological deterioration, brain herniation, and death. Herein, we describe the case of a 76-year-old male who experienced an intracerebral hemorrhage subsequent to a fall and whose injury worsened over time. We summarize the current recommendations in the literature for when to initiate follow-up imaging in patients with traumatic head injury, the risk factors for progression, and the role of close clinical monitoring and serial imaging in managing such patients. Finally, we illustrate how these recommendations were applied in our case.

Hyperemia beneath evacuated acute subdural hematoma is frequent and prolonged in patients with an unfavorable outcome: a xe-computed tomographic study

OBJECTIVE

To verify the values and the time course of regional cerebral blood flow (rCBF) in the cortex located beneath an evacuated acute subdural hematoma (SDH) and their relationship with neurological outcome.

METHODS

rCBF levels were measured in multiple regions of interest, by means of a Xe-computed tomographic technique, in the cortex underlying an evacuated SDH and contralaterally in 20 patients with moderate or severe traumatic brain injury and an evacuated acute SDH. Twenty-three patients with moderate or severe traumatic brain injury and an evacuated extradural hematoma or diffuse injury served as the control group. Outcome was evaluated by means of the Glasgow Outcome Scale at 12 months.

RESULTS

Values for the maximum (rCBFmax) and the mean of all rCBF levels in the cortex beneath the evacuated SDH were more frequently consistent with hyperemia. The side-to-side differences in the mean of all rCBF and rCBFmax levels between lesioned and nonlesioned hemispheres were greater in patients with evacuated SDH than in controls (P = 0.0013 and P = 0.0018, respectively). The side-to-side difference in the maximum rCBF value was higher in SDH patients with unfavorable outcomes than in controls at 24 to 96 hours and at 4 to 7 days and higher than in patients with favorable outcomes at 4 to 7 days. The widest side-to-side difference in rCBFmax value was more elevated in patients with an evacuated SDH with unfavorable outcome than in patients with a favorable outcome (P = 0.047), whereas no differences were found in controls. The SDH thickness and the associated midline shift were greater in patients with unfavorable outcomes than in those with favorable outcomes.

CONCLUSION

On average, hyperemic long-lasting rCBF values frequently occur in the cortex located beneath an evacuated SDH and seem to be associated with unfavorable outcome.

Decompressive craniectomy as the primary surgical intervention for hemorrhagic contusion

The standard surgical treatment of hemorrhagic cerebral contusion is craniotomy with evacuation of the focal lesion. We assessed the safety and feasibility of performing decompressive craniectomy and duraplasty as the primary surgical intervention in this group of patients. Fifty-four consecutive patients with Glasgow Coma Scale (GCS) scores of less than or equal to 8, a frontal or temporal hemorrhagic contusion greater than 20 cm(3) in volume, and a midline shift of at least 5 mm or cisternal compression on computer tomography (CT) scan were studied. Sixteen (29.7%) underwent traditional craniotomy with hematoma evacuation, and 38 (70.4%) underwent craniectomy as the primary surgical treatment. Mortality, reoperation rate, Glasgow Outcome Scale-Extended (GOSE) scores, and length of stay in both the acute care and rehabilitation phase were compared between these two groups. Mortality (13.2% vs. 25.0%) and reoperation rate (7.9% vs. 37.5%) were lower in the craniectomy group, whereas the length of stay in both the acute care setting and the rehabilitation phase were similar between these two groups. The craniectomy group also had better GOSE score (5.55 vs. 3.56) at 6 months. Decompressive craniectomy is safe and effective as the primary surgical intervention for treatment of hemorrhagic contusion. This study also suggests that patient with hemorrhagic contusion can possibly have better outcome after craniectomy than other subgroup of patients with severe traumatic brain injury.

Perfusion-CT for early assessment of traumatic cerebral contusions

INTRODUCTION

To investigate the value of perfusion-CT (PCT) for assessment of traumatic cerebral contusions (TCC) and to compare the abilities of early noncontrast CT and PCT modalities to evaluate tissue viability.

METHODS

PCT studies performed in 30 patients suffering from TCC during the acute phase of their illness were retrospectively reviewed. Cerebral blood flow (CBF), volume (CBV) and mean transit time (MTT) were measured in three different areas: the hemorrhagic core of the TCC, the surrounding hypodense area and the perilesional normal-appearing parenchyma. TCC area was measured on CBF-, CBV- and MTT-derived maps and compared with the areas measured using the same slice obtained with CT scans performed on admission, at the time of PCT (follow-up CT) and at 1 week.

RESULTS

TCC were characterized by low CBF and CBV values (9.2+/-6.6 ml/100 g per min and 0.9+/-0.7 ml/100 g, respectively) and a significant prolongation of MTT (11.9+/-10.7 s) in the hemorrhagic core whereas PCT parameters were more variable in the hypodense area. The TCC whole area showed a noticeable growth of the lesions during the first week of admission. In comparison with early noncontrast CT, CBV and CBF maps proved to be more congruent with the findings of noncontrast CT scans at 1 week.

CONCLUSION

PCT confirmed the results of xenon-CT studies and was shown to allow better evaluation of tissue viability than noncontrast CT. These findings suggest that PCT could be implemented in the future for the early assessment of patients with traumatic brain injury.

Regional cerebral blood flow using quantitative MR angiography

BACKGROUND AND PURPOSE

We sought to derive regional cerebral blood flow using vessel flows from quantitative MR angiography (qMRA).

MATERIALS AND METHODS

Flow rates in the 15 major cerebral arteries were measured on retrospectively gated fast 2D phase-contrast MR angiography obtained in 83 healthy adult volunteers (age range, 24-74 years; mean, 42 years). The arterial network of the brain was partitioned into 12 different regions, in which flows were calculated from the measured flows of the 15 cerebral arteries.

RESULTS

The mean flows of the 15 arteries and the 12 regions were calculated. The mean total cranial flow and the mean total cerebral blood flow were 949 +/- 158 mL/min and 695 +/- 113 mL/min, respectively. The mean regional flows for the anterior and posterior circulation were 483 +/- 87 mL/min and 212 +/- 34 mL/min, respectively. The relative contributions of the flows in the 11 regions to their parent regions were obtained. The mean flows in the individual arteries and the regions with age were also calculated. The mean flows for the female group were significantly lower than those for the male group (P < .001) for the 2 common carotids and the cranial circulation and left/right extracranial circulation. However, the intracranial circulation was not different between sexes.

CONCLUSIONS

The 12 regions in the cerebral circulation were identified and formed into a partition tree, and the mean regional flow for each region was determined using vessel flows from qMRA.

Global cerebral blood flow and CPP after severe head injury: a xenon-CT study

OBJECTIVE

To evaluate the association between global cerebral blood flow and different cerebral perfusion pressure ranges in severe head injury.

DESIGN

A retrospective study

SETTING

Neurosurgical and trauma patients in an intensive care unit in a regional hospital.

PATIENTS AND PARTICIPANTS

Out of a series of 237 consecutive patients with severe head injuries (GCS<or=8), 162 were submitted to ICP monitoring and 89 of them underwent 180 xenon-CT studies and cerebral perfusion pressure (CPP) measurement. The xenon-CT studies did not include any unsalvageable patients nor any mistakenly diagnosed as severe on entry.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Most (95.6%) of xenon-CT studies were obtained with CPP values within the 50-90 mmHg range. Perfusion data were grouped according to CPP values: (1) below 50 mmHg, (2) 50-60 mmHg, (3) 60-70 mmHg, (4) above 70 mmHg. Global cerebral blood flow did not differ among the groups (p=0.49). No differences in physiological variables were found among the CPP groups, except for intracranial pressure, higher in the group with CPP below 50 mmHg, and mean arterial pressure, higher in the CPP above 70 mmHg group (p<0.0001). No differences were found for cerebral metabolic rate of oxygen and lactate.

CONCLUSIONS

There was little correlation between CPP values and global cerebral blood flow levels in our selected patients, probably because pressure autoregulation was preserved. Global metabolism measurements were constant within the groups, suggesting that in patients with controlled physiological variables an interplay between cerebral blood flow and metabolism might be more relevant than the relationship between CPP and cerebral blood flow.

Cerebral blood flow in traumatic contusions is predominantly reduced after an induced acute elevation of cerebral perfusion pressure

OBJECTIVE

To evaluate the response to an acute elevation of cerebral perfusion pressure (CPP) of the regional cerebral blood flow (rCBF) measured in the edematous area of traumatic contusions.

METHODS

rCBF was measured in the intracontusional low-density area, in the pericontusional healthy-appearing brain tissue surrounding the contusion, in a healthy-appearing area in the contralateral hemisphere, in 16 head-injured patients with 16 traumatic contusions larger than 2 cm at baseline, and after 20 minutes of norepinephrine-induced 20-mmHg elevation of CPP levels.

RESULTS

After an induced acute elevation of CPP from baseline values of 65.8 ml/100 g/min (standard deviation, 8.6) to final values of 88.7 ml/100 g/min (standard deviation, 8.9; P < or = 0.0001), we found that rCBF mean levels decreased in the intracontusional low-density area (P = 0.0278), and change in rCBF was inversely associated to the baseline values. After grouping contusions according to the rCBF response to induced acute CPP elevation, rCBF mean values recorded at baseline were significantly lower in lesions with "rCBF improvement" than in those with "rCBF reduction" in the intracontusional low-density area (P = 0.0435).

CONCLUSION

Our findings suggest that CPP elevation induced by norepinephrine is effective in improving contusional rCBF only in selected cases, which are represented by a subset of contusions with critical perfusion, which can be identified by rCBF measurements. Conversely, in contusions with rCBF higher than critical low values, the CPP elevation could probably induce a temporary breakdown of the blood brain barrier, and the norepinephrine leads to a vasoconstriction with a worsening of regional perfusion.

Acute traumatic intraparenchymal hemorrhage: risk factors for progression in the early post-injury period

OBJECTIVE

To characterize the natural course of traumatic intraparenchymal contusions and hematomas (IPHs) and to identify risk factors for IPH progression in the acute post-injury period.

METHODS

A retrospective analysis was performed on a prospective observational database containing 113 head trauma patients exhibiting 229 initially nonoperated acute IPHs. The main outcome variable was radiographic evidence of IPH progression on serially obtained head computed tomographic (CT) scans. Secondary outcomes included the actual amount of IPH growth and later surgical evacuation. Univariate and multivariate analyses (using a generalized estimate equation) were applied to both demographic and initial radiographic features to identify risk factors for IPH progression and surgery.

RESULTS

Overall, 10 IPHs (4%) shrank, 133 (58%) remained unchanged, and 86 (38%) grew between the first and second head CT scan. IPH progression was independently associated with the presence of subarachnoid hemorrhage (odds ratio [OR], 1.6; 95% confidence interval [CI], 1.12-2.3), presence of a subdural hematoma (OR, 1.94; 95% CI, 1.1-3.43), and initial size (OR, 1.11; 95% CI, 1.02-1.21, for each cm volume). Size of initial IPH proportionately correlated with the amount of subsequent growth (linear regression, P < 0.001). Worsened Glasgow Coma Score between initial and follow-up head CT scan (OR, 8.6; 95% CI, 1.5-50), IPH growth greater than 5 cm (OR, 7.3; 95% CI, 1.6-34), and effacement of basal cisterns on initial CT scan (OR, 9.0; 95% CI, 1.5-52) were strongly associated with late surgical evacuation.

CONCLUSION

A large proportion of IPHs progress in the acute post-injury period. IPHs associated with subarachnoid hemorrhage, a subdural hematoma, or large initial size should be monitored carefully for progression with repeat head CT imaging. Effacement of cisterns on the initial head CT scan was strongly predictive of failure of nonoperative management, thereby leading to surgical evacuation. These findings should be important factors in the understanding and management of IPH.

Managing head injured patients

PURPOSE OF REVIEW

In this article we aim to review the recent literature concerning the management of traumatic brain injury patients, summarize the main findings, and discuss the impact of these findings on clinical practice.

RECENT FINDINGS

Several authors have focused on the development of more reliable and informative tools to predict outcome in traumatic brain injury as well as refining the definition of cerebral ischemia in last year's literature. The validity of the current cerebral perfusion pressure management guidelines has also come under scrutiny. It appears that a one size fits all therapy is not a suitable approach for traumatic brain injury patients. An individualized approach, depending on the integrity of pressure autoregulation mechanisms, would be more advisable. Clinical trials investigating brain protective treatments in head injured patients have been disappointing so far. Increasing the homogeneity of patients entering brain protective studies might be an answer. Finally, the use of hyperoxia as well as factors contributing to secondary brain injury such as the occurrence of hyperthermia, with or without an infectious process, have been assessed in head injury patients.

SUMMARY

The key term for the management of traumatic brain injury patients in the early twenty-first century will clearly be 'individualized therapy'. The search of an ideal cerebral perfusion pressure target that would fit every head-injured patients is a utopia. More energy should be focused on the development of reliable tools for outcome prediction and outcome assessment for traumatic brain injured patients. That, and a better targeting of patients entering brain protective trials, should increase the likelihood of demonstrating a significant salvaging effect of a particular treatment in humans.

Cerebral blood flow mapping in two different subtypes of intraparenchymal hemorrhagic traumatic lesions

The pathogenesis and the viability of edematous tissue may be different in traumatic hematomas and traumatic contusions. We tested the hypothesis that mapping of regional Cerebral Blood Flow (rCBF) was different in these two subtypes of traumatic intraparenchymal lesions. We evaluated rCBF by means of Xenon-enhanced computerized tomography (Xe-CT) in 59 traumatic intracerebral lesions from 43 patients with severe head injury. One-hundred-nine intracerebral lesions/Xe-CT CBF measurements were obtained. The rCBF was measured in the hemorrhagic core, in the intralesional oedematous low density area and in a 1 cm rim of apparently normal perilesional parenchyma of both lesion subtypes. Not statistically significant lower rCBF levels were found in the edematous area of traumatic contusions. In traumatic hematomas rCBF levels were lower in the core than in the low density area, suggesting that rCBF in edematous area is marginally involved in the initial traumatic injury and that edema is probably influenced by the persistence of the hemorrhagic core. Conversely, in the traumatic contusions a difference in rCBF values was found between core, low density area and perilesional area, indicating that rCBF of the low density area is related to a concentrical distribution of the initial injury.