Perfusion CT in patients with spontaneous lobar intracerebral hemorrhage: effect of surgery on perihemorrhagic perfusion

Minimally Invasive Intracerebral Hemorrhage Evacuation Improves Pericavity Cerebral Blood Volume

Cerebral blood volume mapping can characterize hemodynamic changes within brain tissue, particularly after stroke. This study aims to quantify blood volume changes in the perihematomal parenchyma and pericavity parenchyma after minimally invasive intracerebral hemorrhage evacuation (MIS for ICH). Thirty-two patients underwent MIS for ICH with pre- and post-operative CT imaging and intraoperative perfusion imaging (DynaCT PBV Neuro, Artis Q, Siemens). The pre-operative and post-operative CT scans were segmented using ITK-SNAP software to calculate hematoma volumes and to delineate the pericavity tissue. Helical CT segmentations were registered to cone beam CT data using elastix software. Mean blood volumes were computed inside subvolumes by dilating the segmentations at increasing distances from the lesion. Pre-operative perihematomal blood volumes and post-operative pericavity blood volumes (PBV) were compared. In 27 patients with complete imaging, post-operative PBV significantly increased within the 6-mm pericavity region after MIS for ICH. The mean relative PBV increased by 21.6 and 9.1% at 3 mm and 6 mm, respectively (P = 0.001 and 0.016, respectively). At the 9-mm pericavity region, there was a 2.83% increase in mean relative PBV, though no longer statistically significant. PBV analysis demonstrated a significant increase in pericavity cerebral blood volume after minimally invasive ICH evacuation to a distance of 6 mm from the border of the lesion.

Prognostic value of CT perfusion and permeability imaging in traumatic brain injury

BACKGROUND

Currently established prognostic models in traumatic brain injury (TBI) include noncontrast computed tomography (CT) which is insensitive to early perfusion alterations associated with secondary brain injury. Perfusion CT (PCT) on the other hand offers insight into early perfusion abnormalities. We hypothesized that adding CT perfusion and permeability data to the established outcome predictors improves the performance of the prognostic model.

METHODS

A prospective cohort study of consecutive 50 adult patients with head injury and Glasgow Coma Scale score of 12 or less was performed at a single Level 1 Trauma Centre. Perfusion CT was added to routine control CT 12 hours to 24 hours after admission. Region of interest analysis was performed in six major vascular territories on perfusion and permeability parametric maps. Glasgow Outcome Scale (GOS) was used 6 months later to categorize patients' functional outcomes to favorable (GOS score > 3) or unfavorable (GOS score ≤ 3). We defined core prognostic model, consisting of age, motor Glasgow Coma Scale score, pupillary reactivity, and CT Rotterdam Score. Next, we added perfusion and permeability data as predictors and compared updated models to the core model using cross-validated areas under the receiver operator curves (cv-AUC).

RESULTS

Significant advantage over core model was shown by the model, containing both mean cerebral extravascular-extracellular volume per unit of tissue volume and cerebral blood volume of the least perfused arterial territory in addition to core predictors (cv-AUC, 0.75; 95% confidence interval, 0.51-0.84 vs. 0.6; 95% confidence interval, 0.37-0.74).

CONCLUSION

The development of cerebral ischemia and traumatic cerebral edema constitutes the secondary brain injury and represents the target for therapeutic interventions. Our results suggest that adding CT perfusion and permeability data to the established outcome predictors improves the performance of the prognostic model in the setting of moderate and severe TBI.

LEVEL OF EVIDENCE

Prognostic study, level III.

Persistent Metabolic Disturbance in the Perihemorrhagic Zone Despite a Normalized Cerebral Blood Flow Following Surgery for Intracerebral Hemorrhage

BACKGROUND

We hypothesized that reduced cerebral blood flow (CBF) and/or energy metabolic disturbances exist in the tissue surrounding a surgically evacuated intracerebral hemorrhage (ICH). If present, such CBF and/or metabolic impairments may contribute to ongoing tissue injury and the modest clinical efficacy of ICH surgery.

OBJECTIVE

To conduct an observational study of CBF and the energy metabolic state in the perihemorrhagic zone (PHZ) tissue and in seemingly normal cortex (SNX) by microdialysis (MD) following surgical ICH evacuation.

METHODS

We evaluated 12 patients (median age 64; range 26-71 yr) for changes in CBF and energy metabolism following surgical ICH evacuation using Xenon-enhanced computed tomography (n = 10) or computed tomography perfusion (n = 2) for CBF and dual MD catheters, placed in the PHZ and the SNX at ICH surgery.

RESULTS

CBF was evaluated at a mean of 21 and 58 h postsurgery. In the hemisphere ipsilateral to the ICH, CBF improved between the investigations (36.6 ± 20 vs 40.6 ± 20 mL/100 g/min; P < .05). In total, 1026 MD samples were analyzed for energy metabolic alterations including glucose and the lactate/pyruvate ratio (LPR). The LPR was persistently elevated in the PHZ compared to the SNX region (P < .05). LPR elevations in the PHZ were predominately type II (pyruvate normal-high; indicating mitochondrial dysfunction) as opposed to type I (pyruvate low; indicating ischemia) at 4 to 48 h (70% vs 30%) and at 49 to 84 h (79% vs 21%; P < .05) postsurgery.

CONCLUSION

Despite normalization of CBF following ICH evacuation, an energy metabolic disturbance suggestive of mitochondrial dysfunction persists in the perihemorrhagic zone.

MR-conditional steerable needle robot for intracerebral hemorrhage removal

BACKGROUND

Intracerebral hemorrhage (ICH) is one of the deadliest forms of stroke in the USA. Conventional surgical techniques such as craniotomy or stereotactic aspiration disrupt a large volume of healthy brain tissue in their attempts to reach the surgical site. Consequently, the surviving patients suffer from debilitating complications.

METHODS

We fabricated a novel MR-conditional steerable needle robot for ICH treatment. The robot system is powered by a custom-designed high power and low-cost pneumatic motor. We tested the robot's targeting accuracy and MR-conditionality performance, and performed phantom evacuation experiment under MR image guidance.

RESULTS

Experiments demonstrate that the robotic hardware is MR-conditional; the robot has the targeting accuracy of 1.26 ± 1.22 mm in bench-top tests. With real-time MRI guidance, the robot successfully reached the desired target and evacuated an 11.3 ml phantom hematoma in 9 min.

CONCLUSION

MRI-guided steerable needle robotic system is a potentially feasible approach for ICH treatment by providing accurate needle guidance and intraoperative surgical outcome evaluation.

The Effect of Cerebrovascular Stenosis on -Peri-Hematoma Cerebral Perfusion and Clinical Outcomes in Patients with Supratentorial Spontaneous Intracerebral Hemorrhage

Background

Many factors are associated with the cerebral hypoperfusion after spontaneous intracerebral hemorrhage (sICH), however, the effect of cerebrovascular stenosis on peri-hematoma cerebral blood flow (CBF) and 90-day poor outcomes in patients with spontaneous intracerebral hemorrhage is still unclear.

Material/Methods

From September 2016 to March 2017, we prospectively collected data on adults with supratentorial spontaneous intracerebral hemorrhages. Using the Propensity Score model, we compared the peri-hematoma CBF and 90-day poor outcomes (mRS ≥3) in the stenosis group and the control group.

Results

Before matching, a total of 116 patients were included in this study, 25 patients in the stenosis group and 91 patients in the control group. After matching, the patients in the stenosis group had a higher absolute decrease of CBF (p=0.003), higher relative decrease of CBF (p=0.016), and higher incidence of 90-day poor outcomes (p=0.041) than the control group. With subgroup analysis, the patients with Glasgow Coma Scale from 13 to 15 (p=0.035), hematoma in the cerebral lobe (p=0.003), mean arterial pressure lower than 120 mm Hg (p=0.003), absolute decrease of CBF higher than 15 mL/100 g per minute (p=0.007), and relative decrease of CBF higher than 30% (p=0.020) had poorer outcomes.

Conclusions

In our series, the stenosis of main cerebral vessels decreased the peri-hematoma CBF and increased the rate of 90-day poor outcomes. Despite higher Glasgow Coma Scale, the evaluation of cerebral perfusion in patients with sICH is needed, especially for the patients with hematoma in the cerebral lobe and lower mean arterial pressure; and treatments to keep adequate cerebral perfusion are needed.

Difference of injury of the corticospinal tract according to surgical or conservative treatment in patients with putaminal hemorrhage

OBJECTIVE

We investigated difference of injury of the corticospinal tract (CST) according to surgical or conservative treatment in patients with putaminal hemorrhage (PH), using diffusion tensor tractography (DTT).

METHODS

Forty-six patients with PH (hematoma volume on the brain CT: 20-40 ml) were recruited. Patients were classified as the surgical treatment group and the conservative treatment group. The hematoma volume on the initial brain CT (median 2 hours after onset; range 1-14 hours) and volumes of the hematoma, the total lesion and the peri-hematomal edema volume on the follow-up brain magnetic resonance imaging (MRI) (median 23.5 days after onset; range 12-46 days) were estimated. Diffusion tensor imaging was performed and we defined the injury of the CST in terms of the configuration or abnormal DTT parameters.

RESULTS

In the conservative treatment group, the total lesion volume on the brain MRI was increased compared with the hematoma volume on the initial brain CT (p < 0.05). On brain MRI, the hematoma volume, peri-hematomal edema volume, and total lesion volume were larger in the conservative treatment group than in the surgical treatment group (p < 0.05). Twelve patients (60%) in the surgical treatment group and 24 patients (92%) in the conservative treatment group had injury of the CST.

CONCLUSION

Injury of the CST was less prevalent in the surgical treatment group than in the conservative treatment group in patients with PH. Therefore, it appears that surgical treatment could be helpful in prevention of injury of the CST in patients with PH.

The influence of decompressive craniectomy for major stroke on early cerebral perfusion

OBJECT

Multiple trials have shown improved survival and functional outcome in patients treated with decompressive craniectomy (DC) for brain swelling following major stroke. It has been assumed that decompression induces an improvement in cerebral perfusion. This observational study directly measured cerebral perfusion before and after decompression.

METHODS

Sixteen patients were prospectively examined with perfusion CT within 6 hours prior to surgery and 12 hours after surgery. Preoperative and postoperative perfusion measurements were compared and correlated.

RESULTS

Following DC there was a significant increase in cerebral blood flow in all measured territories and additionally an increase in cerebral blood volume in the penumbra (p = 0.03). These changes spread as far as the contralateral hemisphere. No significant changes in mean transit time or Tmax (time-to-peak residue function) were observed.

CONCLUSIONS

The presurgical perfusion abnormalities likely reflected local pressure-induced hypoperfusion with impaired autoregulation. The improvement in perfusion after decompression implied an increase in perfusion pressure, likely linked to partial restoration of autoregulation. The increase in perfusion that was observed might partially be responsible for improved clinical outcome following decompressive surgery for major stroke. The predictive value of perfusion CT on outcome needs to be evaluated in larger trials.

Pleiotropic role of PPARγ in intracerebral hemorrhage: an intricate system involving Nrf2, RXR, and NF-κB

Intracerebral hemorrhage (ICH) is a subtype of stroke involving formation of hematoma within brain parenchyma, which accounts for 8-15% of all strokes in Western societies and 20-30% among Asian populations, and has a 1-year mortality rate >50%. The high mortality and severe morbidity make ICH a major public health problem. Only a few evidence-based targeted treatments are used for ICH management, and interventions focus primarily on supportive care and comorbidity prevention. Even in patients who survive the ictus, extravasated blood (including plasma components) and subsequent intrahematoma hemolytic products trigger a series of adverse events within the brain parenchyma, leading to secondary brain injury, edema and severe neurological deficits or death. Although the hematoma in humans gradually resolves within months, full restoration of neurological function can be slow and often incomplete, leaving survivors with devastating neurological deficits. During past years, peroxisome proliferator-activated receptor gamma (PPARγ) transcription factor and its agonists received recognition as important players in regulating not only glucose and lipid metabolism (which underlies its therapeutic effect in type 2 diabetes mellitus), and more recently, as an instrumental pleiotropic regulator of antiinflammation, antioxidative regulation, and phagocyte-mediated cleanup processes. PPARγ agonists have emerged as potential therapeutic target for stroke. The use of PPARγ as a therapeutic target appears to have particularly strong compatibility toward pathogenic components of ICH. In addition to its direct genomic effect, PPARγ may interact with transcription factor, NF-κB, which may underlie many aspects of the antiinflammatory effect of PPARγ. Furthermore, PPARγ appears to regulate expression of Nrf2, another transcription factor and master regulator of detoxification and antioxidative regulation. Finally, the synergistic costimulation of PPARγ and retinoid X receptor, RXR, may play an additional role in the therapeutic modulation of PPARγ function. In this article, we outline the main components of the role of PPARγ in ICH pathogenesis.

The extent of the perihemorrhagic perfusion zone correlates with hematoma volume in patients with lobar intracerebral hemorrhage

INTRODUCTION

Existing data on perfusion imaging assumes the perihemorrhagic zone (PHZ) in patients with intracerebral hemorrhage (ICH) to be size steady. This study investigates the size of the perihemorrhagic zone (PHZ) in patients with lobar ICH in relation to hematoma volume during the course of treatment using perfusion CT (PCT).

METHODS

The present analysis is based on a previously reported cohort of 20 patients undergoing surgical evacuation for lobar SICH, with pre- and early postoperative PCT scanning. Time to peak of the residue function (T max) was measured based on the 360° cortical banding method and singular value decomposition. The size of PHZ was determined before and after treatment and correlated with hematoma volume.

RESULTS

Preoperative mean hematoma volume constituted 63.0 ml (interquartile ranges (IQR) 39.7-99.4 ml), which correlated significantly (r=0.563, p=0.010) with mean PHZ size (5.67 cm, IQR 5.44-8.17 cm). Following a surgical hematoma evacuation, mean hematoma volume was reduced to 2.5 ml IQR 0.0-9.5 ml, which also resulted in a significant reduction of PHZ size to 0.45 cm(IQR 0.0-1.36 cm; p<0.001). There was no association between postoperative hematoma volume and size of the PHZ.

CONCLUSION

Our findings illustrate that the extent of the PHZ cannot be generally assumed to be constant in size and that this differs significantly following hematoma reduction in patients with space occupying lobar SICH.

Clinical application of perfusion computed tomography in neurosurgery

OBJECT

Currently, perfusion CT (PCT) is a valuable imaging technique that has been successfully applied to the clinical management of patients with ischemic stroke and aneurysmal subarachnoid hemorrhage (SAH). However, recent literature and the authors' experience have shown that PCT has many more important clinical applications in a variety of neurosurgical conditions. Therefore, the authors share their experiences of its application in various diseases of the cerebrovascular, neurotraumatology, and neurooncology fields and review the pertinent literature regarding expanding PCT applications for neurosurgical conditions, including pitfalls and future developments.

METHODS

A pertinent literature search was conducted of English-language articles describing original research, case series, and case reports from 1990 to 2011 involving PCT and with relevance and applicability to neurosurgical disorders.

RESULTS

In the cerebrovascular field, PCT is already in use as a diagnostic tool for patients suspected of having an ischemic stroke. Perfusion CT can be used to identify and define the extent of the infarct core and ischemic penumbra core, and thus aid patient selection for acute reperfusion therapy. For patients with aneurysmal SAH, PCT provides assessment of early brain injury, cerebral ischemia, and infarction, in addition to vasospasm. It may also be used to aid case selection for aggressive treatment of patients with poor SAH grade. In terms of oncological applications, PCT can be used as an imaging biomarker to assess angiogenesis and response to antiangiogenetic treatments, differentiate between glioma grades, and distinguish recurrent tumor from radiation necrosis. In the setting of traumatic brain injury, PCT can detect and delineate contusions at an early stage. In patients with mild head injury, PCT results have been shown to correlate with the severity and duration of postconcussion syndrome. In patients with moderate or severe head injury, PCT results have been shown to correlate with patients' functional outcome.

CONCLUSIONS

Perfusion CT provides quantitative and qualitative data that can add diagnostic and prognostic value in a number of neurosurgical disorders, and also help with clinical decision making. With emerging new technical developments in PCT, such as characterization of blood-brain barrier permeability and whole-brain PCT, this technique is expected to provide more and more insight into the pathophysiology of many neurosurgical conditions.

Benefits of a frame-based stereotactic surgical planning system for the treatment of spontaneous intracerebral haematomas

OBJECTIVE

Frame-based stereotactic surgical planning systems (SSPSs) have been used for deep brain stimulation and radioneurosurgery. Here, we evaluated the feasibility, safety and efficacy of using a SSPS to aid spontaneous intracerebral haematoma (ICH) treatment.

METHODS

Patients with moderate spontaneous putamen haematomas were randomized into two groups: treatment (group A) and control (group B). In group B, the catheter for evacuating haematomas was inserted into a target point, located at the centre of the haematoma, using conventional frame-based stereotactics; urokinase thrombolysis was subsequently delivered through the catheter. In group A, this procedure was assisted by a SSPS, which designed both the target point and trajectory in the haematoma through virtual reality. Duration of evacuating haematomas and number of urokinase injections was compared between groups.

RESULTS

In total, 65 patients were recruited: in group A (n = 30), the duration of evacuating haematomas (35.27 ± 9.17 h) was shorter than in group B (n = 35; 67.77 ± 13.82 h). There were fewer urokinase injections in group A (3.63 ± 1.16) than in group B (6.40 ± 1.29).

CONCLUSIONS

The feasibility, efficacy and safety of spontaneous ICH treatment were optimized by the use of a frame-based SSPS.