David M. Pelz

Identification of Penumbra and Infarct in Acute Ischemic Stroke Using Computed Tomography Perfusion–Derived Blood Flow and Blood Volume Measurements

Background and Purpose— We investigated whether computed tomography (CT) perfusion–derived cerebral blood flow (CBF) and cerebral blood volume (CBV) could be used to differentiate between penumbra and infarcted gray matter in a limited, exploratory sample of acute stroke patients. Methods— Thirty patients underwent a noncontrast CT (NCCT), CT angiography (CTA), and CT perfusion (CTP) scan within 7 hours of stroke onset, NCCT and CTA at 24 hours, and NCCT at 5 to 7 days. Twenty-five patients met the criteria for inclusion and were subsequently divided into 2 groups: those with recanalization at 24 hours (n=16) and those without (n=9). Penumbra was operationally defined as tissue with an admission CBF <25 mL · 100 g−1 · min−1 that was not infarcted on the 5- to 7-day NCCT. Logistic regression was applied to differentiate between infarct and penumbra data points. Results— For recanalized patients, CBF was significantly lower (P<0.05) for infarct (13.3±3.75 mL · 100 g−1 · min−1) than penumbra (25.0±3.82 mL · 100 g−1 · min−1). CBV in the penumbra (2.15±0.43 mL · 100 g−1) was significantly higher than contralateral (1.78±0.30 mL · 100 g−1) and infarcted tissue (1.12±0.37 mL · 100 g−1). Logistic regression using an interaction term (CBF×CBV) resulted in sensitivity, specificity, and accuracy of 97.0%, 97.2%, and 97.1%, respectively. The interaction term resulted in a significantly better (P<0.05) fit than CBF or CBV alone, suggesting that the CBV threshold for infarction varies with CBF. For patients without recanalization, CBF and CBV for infarcted regions were 15.1±5.67 mL · 100 g−1 · min−1 and 1.17±0.41 mL · 100 g−1, respectively. Conclusions— We have shown in a limited sample of patients that CBF and CBV obtained from CTP can be sensitive and specific for infarction and should be investigated further in a prospective trial to assess their utility for differentiating between infarct and penumbra.

Cervical spine motion: a fluoroscopic comparison during intubation with lighted stylet, GlideScope, and Macintosh laryngoscope.

The question of which is the optimum technique to intubate the trachea in a patient who may have a cervical(C)-spine injury remains unresolved. We compared, using fluoroscopic video, C-spine motion during intubation for Macintosh 3 blade, GlideScope®, and Intubating Lighted Stylet, popularly known as the Lightwand or Trachlight®. Thirty-six healthy patients were randomized to participate in a crossover trial of either Lightwand or GlideScope to Macintosh laryngoscopy, with in-line stabilization. C-spine motion was examined at the Occiput-C1 junction, C1-2 junction, C2-5 motion segment, and C5-thoracic motion segment during manual ventilation via bag-mask, laryngoscopy, and intubation. Time to intubate was also measured. C-spine motion during bag-mask ventilation was 82% less at the four motion segments studied than during Macintosh laryngoscopy (P < 0.001). C-spine motion using the Lightwand was less than during Macintosh laryngoscopy, averaging 57% less at the four motion segments studied (P < 0.03). There was no significant difference in time to intubate between the Lightwand and the Macintosh blade. C-spine motion was reduced 50% at the C2-5 segment using the GlideScope (P < 0.04) but unchanged at the other segments. Laryngoscopy with GlideScope took 62% longer than with the Macintosh blade (P < 0.01). Thus, the Lightwand (Intubating Lighted Stylet) is associated with reduced C-spine movement during endotracheal intubation compared with the Macintosh laryngoscope.

Comparison of the Bullard and Macintosh Laryngoscopes for Endotracheal Intubation of Patients with a Potential Cervical Spine Injury

Background: In the emergency trauma situation, in‐line stabilization (ILS) of the cervical spine is used to reduce head and neck extension during laryngoscopy. The Bullard laryngoscope may result in less cervical spine movement than the Macintosh laryngoscope. The aim of this study was to compare cervical spine extension (measured radiographically) and time to intubation with the Bullard and Macintosh laryngoscopes during a simulated emergency with cervical spine precautions taken. Methods: Twenty‐nine patients requiring general anesthesia and endotracheal intubation were studied. Patients were placed on a rigid board and anesthesia was induced. Laryngoscopy was performed on four occasions: with the Bullard and Macintosh laryngoscope both with and without manual ILS. Cricoid pressure was applied with ILS. To determine cervical spine extension, radiographs were exposed before and during laryngoscopy. Times to intubation and grade view of the larynx were also compared. Results: Cervical spine extension (occiput‐C5) was greatest with the Macintosh laryngoscope (25.9 [degree sign] +/‐ 2.8 [degree sign]). Extension was reduced when using the Macintosh laryngoscope with ILS (12.9 +/‐ 2.1 [degree sign]) and the Bullard laryngoscope without stabilization (12.6 +/‐ 1.8 [degree sign]; P < 0.05). Times to intubation were similar for the Macintosh laryngoscope with ILS (20.3 +/‐ 12.8 s) and for the Bullard without ILS (25.6 +/‐ 10.4 s). Manual ILS with the Bullard laryngoscope results in further reduction in cervical spine extension (5.6 +/‐ 1.5 [degree sign]) but prolongs time to intubation (40.3 +/‐ 19.5 s; P < 0.05). Conclusions: Cervical spine extension and time to intubation are similar for the Macintosh laryngoscope with ILS and the Bullard laryngoscope without ILS. However, time to intubation is significantly prolonged when the Bullard laryngoscope is used in a simulated emergency with cervical spine precautions taken. This suggests that the Bullard laryngoscope may be a useful adjunct to intubation of patients with potential cervical spine injury when time to intubation is not critical.

White Matter Thresholds for Ischemic Penumbra and Infarct Core in Patients with Acute Stroke: CT Perfusion Study

PURPOSE To prospectively determine the parameters derived at admission computed tomographic (CT) perfusion imaging admission that best differentiate ischemic white matter that recovers from that which infarcts, with the latter retrospectively defined at a CT examination performed without contrast material (unenhanced CT) 5-7 days after the event. MATERIALS AND METHODS Ethics committee approval and informed consent were obtained. Thirty patients with stroke underwent unenhanced CT, CT angiography, and CT perfusion studies at admission. Additionally, CT angiography was performed 24 hours after the stroke, and an unenhanced CT study was performed 5-7 days after the stroke. Five patients were excluded; the remaining patients (10 men, 15 women; mean age, 70 years +/- 13 [standard deviation]) were separated into those with recanalization (n = 16) and those without recanalization (n = 9) at 24 hours. For patients with recanalization, the final infarct was outlined on unenhanced CT images obtained 5-7 days after the event and was superimposed on coregistered maps from the CT perfusion study performed at admission. Ischemic white matter tissue (cerebral blood flow [CBF] < 14 mL/min/100 g) was identified at the admission CT perfusion study, and the penumbra was defined as the difference between the ischemic region and the infarct region. RESULTS Infarct regions showed a matched decrease in CBF and cerebral blood volume (CBV) at admission, whereas penumbra regions showed a significant (P < .05) decrease in CBF but no change in CBV (P > .05) from contralateral values. A threshold CBF . CBV value of 8.14 was the most sensitive (95%, 20 of 21 regions) and specific (94%, 32 of 34 regions) parameter for differentiating between regions of ischemic white matter that recovered and regions of ischemic white matter that infarcted. CONCLUSION The product of CBF and CBV derived from CT perfusion data provided the best differentiation between regions of ischemic white matter that infarcted and regions of ischemic white matter that recovered 5-7 days after a stroke.

Intraluminal thrombus in the cerebral circulation. Implications for surgical management.

Thrombi defined as intraluminal filling defects detected by angiography were identified in 30 patients (29 in the carotid system, one in the vertebral artery). Stroke was the presentation ipsilateral to the thrombus in 22 patients (12 had previous transient ischemic attacks), transient ischemic attacks occurred alone in seven cases, and one patient was asymptomatic. Angiography revealed a severe stenosis in association with the thrombus in 23 patients, a moderate stenosis in four patients, and, in the three patients with only minimal stenosis presumably due to atherosclerosis, there was evidence for a coagulopathy. Sixteen of the 30 patients were operated on urgently, 10 within 24 hours of detection of the thrombus. Twelve of these 16 surgical patients were given anticoagulation before surgery. At endarterectomy, thrombus was identified in 11 of the 14 surgical patients in whom the thrombus was accessible; the other two surgical patients had intracranial thrombus only. In this group, four of 11 surgical patients with accessible thrombi suffered perioperative episodes of new or larger infarction. Fourteen of the 30 patients initially received medical management with no complication. Eight of these 14 medical patients had repeat angiography; seven exhibited complete resolution of thrombus, and six of these seven patients subsequently underwent delayed endarterectomy for the stenosis. No thrombus was identified at surgery in any of the six. One of the six delayed surgery patients suffered a perioperative stroke. Although these numbers are small, reflecting the rarity of thrombus demonstrated by angiography, undetected thrombus is often found at endarterectomy. Its presence may increase operative risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Cervical spine motion: a fluoroscopic comparison of the AirTraq Laryngoscope versus the Macintosh laryngoscope.

Background:The optimal technique to intubate the trachea in patients presenting with a potential or documented cervical spine (C-spine) injury remains unresolved. Using continuous fluoroscopic video assessment, C-spine motion during laryngoscopy with an AirTraq Laryngoscope® (King Medical Systems, Newark, DE) was compared to that with intubation using a Macintosh blade. Methods:Twenty-four healthy surgical patients gave written consent to participate in a crossover randomized controlled trial; all patients were subjected to both Macintosh and AirTraq laryngoscopy with manual inline stabilization after induction of anesthesia. The C-spine motion was examined at four areas: the occiput-C1 junction, C1-C2 junction, C2-C5 motion segment, and C5-thoracic motion segment. The time required for laryngoscopy was also measured. Results:C-spine motion using the AirTraq was less than that during Macintosh laryngoscopy, averaging 66% less (P < 0.01) at three of the motion segments studied, occiput-C1, C2-C5, and C5-thoracic. There was no difference at the C1-C2 segment. There was no significant difference in the time to accomplish laryngoscopy between the two devices. Conclusions:For patients in whom C-spine movement is undesirable, use of the AirTraq Laryngoscope® may be useful to limit movement without an increase in the duration of intubation.

Advances in Interventional Neuroradiology

In 2008 we witnessed a rapid advancement in stent technology, which is reflected in the high number of case reports, publications of case series, and randomized trials. Stents not only served for a combined intrasaccular and extrasaccular treatment of challenging aneurysms but also assisted the revascularization in acute and chronic ischemic conditions of the neurovascular system. Although a self-expanding nitinol semiopen cell stent is currently used for intracranial occlusive disease, a new retrievable closed-cell designed stent is widely used for aneurysms because of its easy delivery through a microcatheter in frequently tortuous head and neck as well as cerebrovascular circulation (Figure 1). However, despite numerous publications in the field, the widespread acceptance of the use of stents to routinely treat carotid stenosis awaits the results of the multicenter randomized clinical trials that should be available in 2009. The role of interventional neuroradiology in the treatment of acute ischemic stroke continues to expand and excite interest.

Endovascular treatment of a lenticulostriate artery aneurysm with N-butyl cyanoacrylate

BACKGROUND Aneurysms arising from lenticulostriate artery branches in moyamoya-type disease are challenging lesions to treat, due to their fragility and deep location. Surgery is difficult and endovascular options may be limited. METHODS A 57-year-old woman presented with a right ganglionic parenchymal hemorrhage due to a ruptured lenticulostriate artery aneurysm associated with ipsilateral middle cerebral artery occlusion. The aneurysm and parent feeding artery were occluded using endovascular injection of N-butyl cyanoacrylate. RESULTS The aneurysm was successfully obliterated and although some glue did enter the more distal middle cerebral artery, there was no change in the patients neurologic status. CONCLUSIONS In highly selected cases where lenticulostriate aneurysms cannot be directly accessed for surgery or endovascular coiling, obliteration with liquid acrylic glue may be considered as a therapeutic option.

Why Calls for More Routine Carotid Stenting Are Currently Inappropriate: An International, Multispecialty, Expert Review and Position Statement

Why Calls for More Routine Carotid Stenting Are Currently Inappropriate An International, Multispecialty, Expert Review and Position Statement

Hemodynamic instability during carotid artery stenting: the relative contribution of stent deployment versus balloon dilation.

OBJECT Hemodynamic instability may complicate carotid angioplasty and stenting in up to 40% of patients. The authors have previously demonstrated that primary self-expanding stent placement alone can gradually dilate severely stenosed carotid arteries without the use of balloons. The authors hypothesized that eliminating the balloon would reduce carotid baroreceptor stimulation, thereby decreasing the incidence of hemodynamic instability. METHODS Ninety-seven high surgical risk patients with symptomatic, severely stenosed carotid arteries were treated with the intention of using a self-expanding stent alone. Seventy-seven arteries (79%) were treated with stenting alone, and 20 required angioplasty (21%). RESULTS Intraprocedural bradycardia (heart rate < 60 bpm) developed in 29 patients (38%) and hypotension (systolic blood pressure < 90 mm Hg) occurred in 1 patient (1%) treated with stenting alone. Fourteen patients (70%) who underwent angioplasty and stenting had bradycardia, and hypotension developed in 4 (20%). Atropine, glycopyrrolate, or vasopressors were required in 8% of patients who received stenting alone, compared to 30% of patients who underwent angioplasty. In the first 24 hours after treatment, hypotension or bradycardia developed in 25 patients (32%) who had undergone stent placement alone, and in 15 patients (75%) after stent placement and balloon angioplasty. There was no difference in the occurrence of intra- or postprocedural hypertension (systolic blood pressure > 160 mm Hg) between patients treated with stenting alone or stenting and balloons. Factors independently associated with hemodynamic depression included baseline heart rate and balloon use. CONCLUSIONS Hemodynamic instability during and after carotid artery stenting was observed more frequently when balloon angioplasty was required than when stent placement was performed without concurrent balloon angioplasty.