The utility of preoperative diffusion tensor imaging in the surgical management of brainstem cavernous malformations.

OBJECT: Resection of brainstem cavernous malformations (BSCMs) may reduce the risk of stepwise neurological deterioration secondary to hemorrhage, but the morbidity of surgery remains high. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT) are neuroimaging techniques that may assist in the complex surgical planning necessary for these lesions. The authors evaluate the utility of preoperative DTI and DTT in the surgical management of BSCMs and their correlation with functional outcome. METHODS: A retrospective review was conducted to identify patients who underwent resection of a BSCM between 2007 and 2012. All patients had preoperative DTI/DTT studies and a minimum of 6 months of clinical and radiographic follow-up. Five major fiber tracts were evaluated preoperatively using the DTI/DTT protocol: 1) corticospinal tract, 2) medial lemniscus and medial longitudinal fasciculus, 3) inferior cerebellar peduncle, 4) middle cerebellar peduncle, and 5) superior cerebellar peduncle. Scores were applied according to the degree of distortion seen, and the sum of scores was used for analysis. Functional outcomes were measured at hospital admission, discharge, and last clinic visit using modified Rankin Scale (mRS) scores. RESULTS: Eleven patients who underwent resection of a BSCM and preoperative DTI were identified. The mean age at presentation was 49 years, with a male-to-female ratio of 1.75:1. Cranial nerve deficit was the most common presenting symptom (81.8%), followed by cerebellar signs or gait/balance difficulties (54.5%) and hemibody anesthesia (27.2%). The majority of the lesions were located within the pons (54.5%). The mean diameter and estimated volume of lesions were 1.21 cm and 1.93 cm(3), respectively. Using DTI and DTT, 9 patients (82%) were found to have involvement of 2 or more major fiber tracts; the corticospinal tract and medial lemniscus/medial longitudinal fasciculus were the most commonly affected. In 2 patients with BSCMs without pial presentation, DTI/DTT findings were important in the selection of the surgical approach. In 2 other patients, the results from preoperative DTI/DTT were important for selection of brainstem entry zones. All 11 patients underwent gross-total resection of their BSCMs. After a mean postoperative follow-up duration of 32.04 months, all 11 patients had excellent or good outcome (mRS Score 0-3) at the time of last outpatient clinic evaluation. DTI score did not correlate with long-term outcome. CONCLUSIONS: Preoperative DTI and DTT should be considered in the resection of symptomatic BSCMs. These imaging studies may influence the selection of surgical approach or brainstem entry zones, especially in deep-seated lesions without pial or ependymal presentation. DTI/DTT findings may allow for more aggressive management of lesions previously considered surgically inaccessible. Preoperative DTI/DTT changes do not appear to correlate with functional postoperative outcome in long-term follow-up.

Automated quantification of white matter disease extent at 3 T: comparison with volumetric readings.

PURPOSE: To develop and validate an algorithm to automatically quantify white matter hyperintensity (WMH) volume. MATERIALS AND METHODS: Images acquired as part of the Dallas Heart Study, a multiethnic, population-based study of cardiovascular health, were used to develop and validate the algorithm. 3D magnetization prepared rapid acquisition gradient echo (MP-RAGE) and 2D fluid-attenuated inversion recovery (FLAIR) images were acquired from 2082 participants. Images from 161 participants (7.7% of the cohort) were used to set an intensity threshold to maximize the agreement between the algorithm and a qualitative rating made by a radiologist. The resulting algorithm was run on the entire cohort and outlier analyses were used to refine the WMH volume measurement. The refined, automatic WMH burden estimate was then compared to manual quantitative measurements of WMH volume in 28 participants distributed across the range of volumes seen in the entire cohort. RESULTS: The algorithm showed good agreement with the volumetric readings of a trained analyst: the Spearman's Rank Order Correlation coefficient was r = 0.87. Linear regression analysis showed a good correlation WMHml[automated] = 1.02 × WMHml[manual] - 0.48. Bland-Altman analysis showed a bias of 0.34 mL and a standard deviation of 2.8 mL over a range of 0.13 to 41 mL. CONCLUSION: We have developed an algorithm that automatically estimates the volume of WMH burden using an MP-RAGE and a FLAIR image. This provides a tool for evaluating the WMH burden of large populations to investigate the relationship between WMH burden and other health factors.

Computed tomography in the diagnosis of occult open-globe injuries.

PURPOSE: To determine the radiographic signs present on computed tomography (CT) most suggestive of occult open-globe injury. DESIGN: Retrospective chart review. PARTICIPANTS: Forty-eight eyes (of 46 patients), 34 of which were found to have an occult open-globe injury on surgical exploration. METHODS: A retrospective chart review of all eyes of patients 18 years or older undergoing surgical exploration to rule out occult open-globe injury after CT examination at Parkland Memorial Hospital between October, 1998, and September, 2003, was conducted. Patients with obvious corneal or corneoscleral lacerations or with uveal prolapse were excluded. The CT films were obtained and independently reviewed by 3 masked observers (2 neuroradiologists and 1 ophthalmologist). MAIN OUTCOME MEASURES: Presence of occult open-globe injury with respect to radiographic globe and orbital findings. RESULTS: The sensitivity of CT for determining occult open-globe injury varied from 56% to 68% between the observers, specificity ranged from 79% to 100%, positive predictive value ranged from 86% to 100%, and negative predictive value ranged from 42% to 50%. Open-globe injuries averaged more CT findings per patient compared with intact globes (P = 0.047). Statistically significant CT findings for occult open-globe injury included any change in globe contour (P = 0.001), obvious volume loss (P = 0.003), an absent or dislocated lens (P = 0.048), vitreous hemorrhage (P = 0.003), and retinal detachment (P = 0.044). Additionally, moderate to severe change in globe contour, obvious volume loss, total vitreous hemorrhage, and absence of lens were seen only in eyes with occult rupture. CONCLUSIONS: Although CT scanning may provide valuable information in patients in whom an occult open-globe injury is suspected, its sensitivity and specificity are inadequate to be relied on fully, and such patients generally should be taken to the operating room for formal surgical evaluation. Significant changes in globe contour or obvious volume loss are strong predictors of globe rupture, and any vitreous hemorrhage should be a concern for occult injury.