Embolic Stroke Diagnosed by Elevated D-Dimer in a Patient With Negative TEE for Cardioembolic Source.

We report a case of cerebrovascular accident with thromboembolic stroke etiology in a patient who had atrial flutter and negative transesophageal echocardiography (TEE) results. The increased D-dimer levels (1877 ng/mL) initiated referral for magnetic resonance imaging and magnetic resonance angiography of the brain that showed classic recanalization of an embolic thrombus in the angular branch of the left middle cerebral distribution. The D-dimer level of this patient was normalized after 3 months of anticoagulation therapy. Although TEE is considered the gold standard for evaluation of cardiac source of embolism, exclusion of intracardiac thrombus with TEE alone does not eliminate the risk of thromboembolic events. This case highlights the utility of D-dimer as a potential adjunct in the decision-making process to guide investigation of thromboembolism, determine subsequent therapy, and hence reduce the risk of embolic stroke recurrence.

Analysis of the jugular foramen in pediatric patients with craniosynostosis.

INTRODUCTION: Intracranial hypertension due to craniosynostosis is a dreaded potential complication that affects the developing brain. We hypothesized that craniosynostotic patients have significantly reduced jugular foramen (JF) when compared with age-matched controls. This may partially account for the observed increase in intracranial pressure (ICP) seen in some of these patients. We also estimated the potential effects on ICP using the Hagen-Poiseuille equation. MATERIALS AND METHODS: Two institutional review board-approved groups were included in this study. Group 1 consists of 14 randomly selected craniosynostotic patients (7 boys and 7 girls; mean age, 9.33 mo; range, 0.6-21 mo). Group 2, the control group, consists of 27 children without craniosynostosis (13 boys and 14 girls; mean age, 8.71 mo; range, 0.23-45 mo). The same neuroradiologist used axial computed tomographic scans to measure the greatest anterior-posterior (AP) and lateral diameters of the jugular bulb. RESULTS: The right JF AP diameter is 23.02% smaller in group 1 than in group 2 (P = 0.0066, 2-tailed t-test). The left JF AP diameter was also smaller for group 1 but was not statistically significant (P = 0.257, 2-tailed t-test). Group 1 also had a nonsignificant increase in both lateral diameters (P > 0.05). DISCUSSION: The study showed a significant decrease (23.02%) in the right JF AP dimension in children with craniosynostosis. On the basis of the Hagen-Poiseuille equation, a 23.02% AP diameter reduction in 1 JF may theoretically increase the ICP 63.5% or 6.35 mm Hg, keeping all other variables, such as blood flow, constant. Although not supported by aspect ratio analysis, the slight increase in the lateral diameters of the patients' JFs may lessen this effect.

From presentation to follow-up: diagnosis and treatment of cerebral venous thrombosis.

Cerebral venous thrombosis is an uncommon cause of stroke but remains a challenge for physicians faced with this diagnosis largely due to the variability in presentation. Anticoagulation, typically with intravenous heparin, remains the mainstay of treatment for stable patients and is sufficient in the majority of cases. However, a significant mortality rate exists for cerebral venous thrombosis due to patients who deteriorate or do not adequately respond to initial treatments. It is in these patients that more aggressive interventions must be undertaken. The neurosurgeon is often called on, either acutely for initial evaluation of the stroke or venous hemorrhage or after the failure of initial therapy for clot evacuation, hemicraniectomy, or thrombectomy. A proper workup must include a search for an underlying, correctable cause as well as thorough follow-up with correction of identified risk factors to decrease the risk of recurrent disease.

The use of portable intraoperative computed tomography scanning for real-time image guidance: a pilot cadaver study.

BACKGROUND: This study was performed to assess the feasibility of using intraoperative computed tomography (CT) to provide real-time updates to image guidance systems (IGSs) during surgery. METHODS: The xCAT ENT portable intraoperative CT scanner (Xoran Technologies, Ann Arbor, MI) was used to acquire scans before, midway, and at the end of six cadaver dissections during the Southern States Rhinology Course, Augusta, GA, in October 2006. These scans were used to recalibrate three different IGSs used during the dissection. Time measurements were recorded and dosimetry was obtained from the cornea, sphenoid sinus (near the optic chiasm), and from the operative field during acquisition of the images. IGS accuracy was determined at the skull base and lamina papyracea. Surgeons were interviewed on benefits of real-time updates to the IGS after completion of dissections. RESULTS: The xCAT ENT scanner was compatible with all three IGS platforms. The average time to update the IGS was 13 minutes. Radiation doses to the cornea were 620 mrad per scan, and optic chiasm was 800 mrad/scan. The accuracy at the anterior skull base improved from 1.58 to 0.62 mm (p=0.026). The accuracy at the posterior skull base improved from 1.46 to 0.71 mm (p=0.014). The accuracy at the lamina was not significantly changed. CONCLUSION: Intraoperative portable CT scanning with real-time IGS updates is feasible and likely would add little additional time. Accuracy is improved at the skull base. Prospective studies on actual patients are warranted.

Anatomic measurements for the endoscopic modified Lothrop procedure.

BACKGROUND: The aim of this study was to introduce preoperative radiographic frontal recess and sinus anatomic measurements to assist in the selection of patients considered for the modified Lothrop procedure. METHODS: Data were collected from sagittally reconstructed computed tomography (CT) scans of seven cadaver heads. Four anatomic parameters for measurement were defined as follows: (1) thickness of the nasal beak (desirable < 10 mm); (2) midsagittal distance from nasal beak to skull base (adding 1 and 2 provides the anterior-posterior (AP) space at the cephalad margin of the frontal recess; desirable, > or = 15 mm); (3) accessible dimension (in a parasagittal plane through the frontal ostium; the distance between two lines drawn parallel to the plane of the anterior skull base and perpendicular to the line of the insertion of the nasal endoscope during surgery; the posterior line is drawn at the skull base and the anterior line is drawn at the posterior margin of the nasal beak; the distance between the lines indicates the space available for instrumentation; desirable, > 5 mm); (4) AP dimension of each frontal sinus. RESULTS: The average and the range of each parameter measured were as follows: (1) nasal beak thickness = 8.0 mm (5.0-10.4 mm); (2) nasal beak-skull base = 7.9 mm (2.5-14.1 mm); (3) accessible dimension, 6.1 mm (0.9-9.6 mm); (4) AP diameter of the frontal sinus, 9.7 mm (5.2-14.1 mm). Four specimens were considered candidates for modified Lothrop and three were not. CONCLUSION: Preoperative radiographic frontal recess and sinus anatomic measurements may assist in the selection of patients considered for the endoscopic modified Lothrop procedure.

Study of subclinical cerebral edema in diabetic ketoacidosis by magnetic resonance imaging T2 relaxometry and apparent diffusion coefficient maps.

Cerebral edema is the most significant complication in children with diabetic ketoacidosis (DKA). Our goal was to study whether subclinical cerebral edema was preferentially vasogenic or cytotoxic. Magnetic resonance imaging (MRI)--diffusion-weighted imaging (DWI) and T2 relaxometry (T2R)--were obtained in pediatric patients presenting with severe diabetic ketoacidosis (DKA) 6-12 hours after initial DKA treatment and stabilization and 96 hours after correction of DKA. T2 relaxometry was significantly increased during treatment in both white and gray matter, in comparison to the absolute T2R values 96 hours after correction of DKA (p = .034). Classic intracellular cytotoxic edema could not be detected, based on the lack of a statistically significant decrease in ADC values. ADC values were instead elevated, implying a large component of cell membrane water diffusion, correlating with the elevated white and gray matter T2R We discuss the findings in relation to cerebral blood volume, cerebral vasoregulatory dysfunction, and cerebral hyperemia.