Wenzhuan He

Predicting aneurysm rupture probabilities through the application of a computed tomography angiography-derived binary logistic regression model

OBJECT The goal of this study was to establish a biomathematical model to accurately predict the probability of aneurysm rupture. Biomathematical models incorporate various physical and dynamic phenomena that provide insight into why certain aneurysms grow or rupture. Prior studies have demonstrated that regression models may determine which parameters of an aneurysm contribute to rupture. In this study, the authors derived a modified binary logistic regression model and then validated it in a distinct cohort of patients to assess the models stability. METHODS Patients were examined with CT angiography. Three-dimensional reconstructions were generated and aneurysm height, width, and neck size were obtained in 2 orthogonal planes. Forward stepwise binary logistic regression was performed and then applied to a prospective cohort of 49 aneurysms in 37 patients (not included in the original derivation of the equation) to determine the log-odds of rupture for this aneurysm. RESULTS A total of 279 aneurysms (156 ruptured and 123 unruptured) were observed in 217 patients. Four of 6 linear dimensions and the aspect ratio were significantly larger (each with p < 0.01) in ruptured aneurysms than unruptured aneurysms. Calculated volume and aneurysm location were correlated with rupture risk. Binary logistic regression applied to an independent prospective cohort demonstrated the models stability, showing 83% sensitivity and 80% accuracy. CONCLUSIONS This binary logistic regression model of aneurysm rupture identified the status of an aneurysm with good accuracy. The use of this technique and its validation suggests that biomorphometric data and their relationships may be valuable in determining the status of an aneurysm.

Three dimensional CT angiography versus digital subtraction angiography in the detection of intracranial aneurysms in subarachnoid hemorrhage

Introduction Ruptured intracranial aneurysms are responsible for over 90% of cases of spontaneous subarachnoid hemorrhage (SAH). Conventional digital subtraction angiography (DSA) remains the gold standard for diagnosing the source of SAH. A prospective study is presented wherein SAH patients underwent three dimensional CT angiography (CTA) prior to DSA in order to assess the specificity and sensitivity of this non-invasive modality to detect aneurysms. Methods 179 consecutive patients with spontaneous SAH presented over 36 months, as identified by screening CT and CTA. Patients with negative CTA findings underwent DSA within 24 h of presentation. All patients who were determined to have angiographically negative SAH underwent follow-up DSA 2 weeks later. Results Of the 179 patients screened by CTA, 13 (7%) were negative for aneurysms or other vascular lesions (arteriovenous malformation or dural fistula) on CTA and underwent DSA. No new lesions were identified on six vessel angiography, resulting in a 0% false negative rate (sensitivity 100%, predictive value 100%). MRI to rule out thrombosed aneurysms and repeat angiography at the 2 week follow-up were negative. Conclusions Sensitivity and specificity were higher than previously reported, suggesting that CTA may be used as an initial screening tool in lieu of DSA. Further studies are necessary to determine if CTA can supplant DSA in ruling out all forms of vascular disease in idiopathic SAH.

Endovascular treatment for acute ischemic stroke in octogenarians compared with younger patients: a meta-analysis.

Background Little is known about the safety and efficacy of endovascular therapy for acute ischemic stroke in octogenarians. Aim We performed a systematic review and meta-analysis of published studies comparing outcomes of octogenarians and younger patients after endovascular treatment for acute ischemic stroke. Methods A computerized search of the medical literature from 1990 to 2012 was performed to identify comparative studies of endovascular treatment of ischemic stroke patients 80 years or older and younger patients. Data on clinical outcomes, mortality, symptomatic intracerebral hemorrhage, and recanalization were abstracted. Results Data from eight studies with 2729 patients were included in the final analysis. Good functional outcome defined as modified Rankin score 2 or less within 90 days was more common in younger patients compared with octogenarians [odds ratio 2·694; 95% confidence interval 1·941–3·740, P < 0·001). Symptomatic hemorrhage and death were significantly more come in patients 80 years or older (odds ratio 1·604; 95% confidence interval 1·013–2·540, P = 0·04 and odds ratio 3·695; 95% confidence interval 2·517–5·424, P < 0·001, respectively). Successful recanalization defined as Thrombolysis in Myocardial Infarction (TIMI) 2–3 was seen less frequently in older patients; however, this did not reach statistical significance (odds ratio 0·814; 95% confidence interval 0·522–1·269, P = 0·364). Conclusion Formal meta-analysis showed that octogenarians are less likely to achieve functional independence and have higher rates of mortality and intracerebral hemorrhage following endovascular treatment for ischemic stroke compared with younger patients. Decisions regarding endovascular treatment of elderly patients should be individualized until randomized controlled trials are available.

The use of Hypertonic Saline in the Treatment of Post-Traumatic Cerebral Edema: A Review

Effective methods for treating cerebral edema have recently become a matter of both extensive research and significant debate within the neurosurgery and trauma surgery communities. The pathophysiologic progression and outcome of different forms of cerebral edema associated with traumatic brain injury have yet to be fully elucidated. There are heterogeneous factors influencing the onset and progress of post-traumatic cerebral edema, including the magnitude and type of head injury, age, co-morbid conditions of the patient, the critical window for therapeutic intervention and the presence of secondary insults including hypoxia, hypotension, hypo/hyperthermia, degree of raised intracranial pressure (ICP), and disruption of blood brain barrier (BBB) integrity. Although numerous studies have been designed to improve our understanding of the etiology of post-traumatic cerebral edema, therapeutic interventions have traditionally been focused on minimizing secondary insults especially raised ICP and improving cerebral perfusion pressure. More recently, fluid resuscitation strategies using hyperosmolar agents such as pentastarch and hypertonic saline (HS) have achieved some success. HS treatment is of particular interest due to its apparent advantageous action over other types of hyper-osmotic solutions in both clinical and laboratory studies. In this review, we provide a summary of recent literature concerning the pathogenesis and mechanisms involved in the various types of cerebral edema, and the possible mechanisms of action of HS for the treatment cerebral edema.

Computed tomographic angiography versus digital subtraction angiography for the postoperative detection of residual aneurysms: a single-institution series and meta-analysis

Background Computed tomographic angiography (CTA) has recently emerged as a non-invasive alternative to digital subtraction angiography (DSA) for the detection of residual cerebral aneurysms (RA). Objective To compare the diagnostic accuracy of CTA with the current ‘gold standard’, DSA, in the postoperative detection of RA. Methods Patient data from this single institution were prospectively gathered, and imaging results retrospectively blinded and analyzed. Between 2001 and 2005 eligible patients received microsurgical repair of cerebral aneurysms and were evaluated postoperatively by DSA and CTA. These single-institutional data were compiled with qualified studies published from 1997 to 2009, and a meta-analysis was performed. Results This institutional series reports sensitivity, specificity, positive (PPV) and negative predictive values (NPV) of 100%. Eleven studies met the inclusion criteria for the meta-analysis. A total of 427 patients with 513 aneurysms were included, with 61 RA detected by DSA and 40 detected by CTA. Unweighted analysis resulted in pooled sensitivity of 73.8%, specificity of 96.3%, PPV of 91.0% and NPV of 86.1%. Stratified analysis of studies using 16-slice CTA versus 2D DSA reported pooled sensitivity of 92.6%, specificity of 99.3%, PPV of 95.8%, and NPV of 97.8%. Conclusions This meta-analysis supports CTA as an acceptable modality for postoperative detection of RA, although DSA remains the gold standard. By implementing multidetector CTA technology in experienced centers, the sensitivity and specificity of CTA may approach that of traditional DSA for detecting RA. As a cost-effective, non-invasive modality, CTA is a promising alternative to DSA for initial and long-term evaluation of RA.

Biomorphometric Markers for Aneurysm Rupture in Posterior Communicating Artery Aneurysms.

Introduction: The mathematical modeling of aneurysms has been critical in helping to understand the biophysical phenomena that contribute to aneurysm growth and rupture. Prior studies have demonstrated that complex binary logistic regression models may determine which physical parameters of an aneurysm contribute to aneurysm rupture. Because of the posterior communicating artery (PCoA) aneurysms high propensity for rupture, we studied and derived a relational equation that describes the rupture potential for PCoA aneurysms within …

Monitoring papilledema in a patient with pineal pilocytic astrocytoma by using Heidelberg Retina Tomograph II. Case report.

The Heidelberg Retina Tomograph (HRT) II is a confocal scanning laser device used to acquire images of the optic nerve head. In this paper the authors report a novel use of this device in the assessment of papilledema in a patient with pilocytic astrocytoma of the pineal region. They also present a new technique to objectively produce 3D data of the optic nerve head. An 11-year-old girl presented with headache and bilateral papilledema; magnetic resonance imaging revealed a lesion in the pineal region. A suboccipital craniectomy was performed, and HRT images were obtained both before (baseline) and after (follow-up) the operation. The authors analyzed the height variation of the retinal surface along the vertical and horizontal cross-lines passing the center of the optic nerve head. The postoperative images, studied on the 2nd day after operation, demonstrated visible reduction of the papilledema. The height variation of the retinal surface along the contour line created by the software demonstrated that elevation of the optic nerve head became depressed due to resolved swelling. The height variation of the retinal surface along vertical and horizontal cross-lines demonstrated significant differences between the elevated preoperative curve and the postoperative curve (p < 0.001), consistent with improvement of her symptoms. Initial data suggest that changes in the optic nerve head topography after surgical decompression can be quantitatively documented by 3D data from the HRT II.

Measurements of eye distortions caused by elevated intracranial pressure

We have measured the optical disc region in the eye of patients with elevated intracranial pressure (ICP). We used a scanning laser ophthalmoscope (SLO), which gives a digital measure of the topology. We formulated two measures of the swelling caused by high ICP (called papilledema): 1) depth of the optic disc, and 2) average mean diameter of the swelling. We show that these quantitative evaluations vary systematically with a physicians qualitative grading of the severity of the papilledema.

E-062 True aneurysms of the posterior communicating artery: a systematic review and meta-analysis of individual patient data

Introduction The term ‘true’ posterior communicating artery (PCoA) aneurysm refers to an aneurysm that originates from the posterior communicating artery itself. Over the past decades, an increasing number of this type of posterior communicating artery aneurysms have been reported. We systematically reviewed all of these published data and conducted a meta-analysis on these individual patient data. Method A meta-analysis of individual patient data was conducted. Results Pooled data demonstrated that ‘true’ PCoA aneurysms represented about 1.3% (95% CI 0.8% to 1.7%) of all intracranial aneurysms and 6.8% (95% CI 4.3% to 9.2%) of all PCoA aneurysms. Mean age was 53.5 (53.5±15.4) years and ranged between 23 and 79 years. 49 of these reported aneurysms had the ruptured status, 44 (89.8%) were reported as ruptured and four (10.2%) were reported as unruptured. There were no significant differences in ruptured status between age (p=0.321), aneurysm side (p=0.537) and shape (p=0.408). No significant differences in complication rates were found between the different ruptured status (p=0.27) or operative modalities (p=0.878). Mean ages of those patients who had no complications and those who had complications were 53 (53±2.59) versus 53.2 (53.2±5.02) years (p =0.972). Conclusion We concluded that ‘true’ PCoA aneurysms represent about 1.3% of all intracranial aneurysms and 6.8% of all posterior communicating artery aneurysms. ‘True’ PCoA aneurysms are more prone to rupture compared with their counterpart junctional aneurysms. When surgical management is indicated, care should be taken in choosing the operative approach to avoid oculomotor nerve damage and to preserve perforating branches as much as possible. A good understanding of the location and configuration of the aneurysm neck before surgical treatment is critical in successful treatment of these lesions.Abstract E-062 Figure 1

007 Aneurysm angle and deflection as markers for aneurysm rupture in posterior communicating artery aneurysms: a biomorphometric analysis

Introduction: Mathematical modeling of aneurysms is critical in gaining understanding into the biophysical phenomena that contribute to aneurysm growth and rupture. Prior studies have demonstrated certain primary and secondary biomorphometric characteristics which correlate with aneurysm rupture. Aneurysms of the posterior communicating artery (PCoA) have a high propensity for rupture. This study analyzes the relationship between aneurysm rupture status and the angular relationships between the aneurysm, internal carotid (ICA) the …