Laser speckle imaging identification of increases in cortical microcirculatory blood flow induced by motor activity during awake craniotomy.

OBJECT: The goal of awake neurosurgery is to maximize resection of brain lesions with minimal injury to functional brain areas. Laser speckle imaging (LSI) is a noninvasive macroscopic technique with high spatial and temporal resolution used to monitor changes in capillary perfusion. In this study, the authors hypothesized that LSI can be useful as a noncontact method of functional brain mapping during awake craniotomy for tumor removal. Such a modality would be an advance in this type of neurosurgery since current practice involves the application of invasive intraoperative single-point electrocortical (electrode) stimulation and measurements. METHODS: After opening the dura mater, patients were woken up, and LSI was set up to image the exposed brain area. Patients were instructed to follow a rest-activation-rest protocol in which activation consisted of the hand-clenching motor task. Subsequently, exposed brain areas were mapped for functional motor areas by using standard electrocortical stimulation (ECS). Changes in the LSI signal were analyzed offline and compared with the results of ECS. RESULTS: In functional motor areas of the hand mapped with ECS, cortical blood flow measured using LSI significantly increased from 2052 ± 818 AU to 2471 ± 675 AU during hand clenching, whereas capillary blood flow did not change in the control regions (areas mapped using ECS with no functional activity). CONCLUSIONS: The main finding of this study was that changes in laser speckle perfusion as a measure of cortical microvascular blood flow when performing a motor task with the hand relate well to the ECS map. The authors have shown the feasibility of using LSI for direct visualization of cortical microcirculatory blood flow changes during neurosurgery.

Predictive value of infant lung function testing for airway malacia.

Airway malacia is present in a small proportion of wheezing infants. The usefulness of infant lung-function testing (ILFT) in ruling out malacia in wheezy infants is unknown. We assessed the predictive value of ILFT parameters for airway malacia diagnosed by flexible bronchoscopy. Thirty-two term infants (mean (SD) age, 11.0 (4.6) months) with chronic wheeze unresponsive to asthma treatment underwent ILFT prior to bronchoscopy. Functional residual capacity measured by plethysmograph (FRCp), maximal flow at FRC (V'max(FRC)), and tidal breathing parameters were obtained. Expiratory flow-volume curves were visually examined for tidal flow limitation. Malacia was observed during bronchoscopy in 20 infants. V'max(FRC) (Z-score) was significantly lower in the group with malacia as compared with the group without malacia. Lung-function measurements had a low negative predictive value and sensitivity. While flow limitation during tidal breathing was highly predictive and 100% specific for airway malacia, only half of the infants with malacia had tidal flow limitation. In this selected group of infants, routine lung function testing could not discriminate between infants with and without airway malacia. However, the presence of tidal flow limitation was 100% predictive and specific for airway malacia.

Reliability of tendon excursion measurements in patients using a color Doppler imaging system.

PURPOSE: The purpose of this study was to assess the test-retest reliability of tendon excursion measurements with color Doppler imaging in patients with flexor tendon injuries following a modified Kleinert protocol. METHODS: One observer performed repeated measurements at 3 different time periods in 13 patients with flexor tendon injuries, following a modified Kleinert protocol. The intraclass correlation coefficient (ICC), the standard error of measurement (SEM), and related indices of measurement error were calculated. RESULTS: Measurements at 10 day after surgery had an ICC of.88 and an SEM of 1.1 mm. Measurements at 6 weeks after surgery had an ICC of.58 and an SEM of 2.0 mm. The measurements after 3 months had an ICC of.94 and an SEM of 1.2 mm. CONCLUSION: Measurements at 10 days and more than 3 months after surgery were reliable and were as reliable as the measurements performed on healthy subjects. At 6 weeks after surgery the measurements were less reliable. Color Doppler imaging is a reliable and noninvasive method to assess tendon excursion, even in patients with small tendon excursion movements.

Non-invasive measurement of tendon excursion with a colour Doppler imaging system: a reliability study in healthy subjects.

The excursion of the flexor digitorum profundus tendon during active flexion of the third finger was measured with colour Doppler imaging in 10 healthy volunteers. Repeated measurements were made by one observer in three sessions to assess the test-retest reliability. An analysis of variance (ANOVA) was done to find out the multiple sources of measurement error. The intraclass correlation coefficient was 0.81. For single measurements, the standard error of measurement was not more than 0.17 cm. The smallest detectable difference between two consecutive measurements was 0.48 cm. The test-retest reliability of colour Doppler measurements of excursion of the flexor digitorum profundus III tendon (FDP III) in healthy subjects is good. With series of 25 flexion movements, colour Doppler imaging is applicable in the assessment of tendon excursions in patients.

Worsening of V'maxFRC in infants with chronic lung disease in the first year of life: a more favorable outcome after high-frequency oscillation ventilation.

Little is known about the development of maximal flow at functional residual capacity, a measure of airway patency, in infants with chronic lung disease (CLD). In a follow-up study, we evaluated V'maxFRC in very low birth weight infants with CLD, treated with high-frequency oscillation ventilation (HFOV) or conventional mechanical ventilation. In 36 infants with CLD, V'maxFRC was evaluated at 6 and/or 12 months corrected age, and the relationship between perinatal factors and lung function was studied. Mean (SD) birth weight and gestational age were 837 (152) g and 26.8 (1.7) weeks, respectively. At 6 and 12 months, mean V'maxFRC was significantly below normal. Between 6 and 12 months, there was a mean (95% confidence interval) reduction in V'maxFRC (Z score) of 0.5 (0.2-0.7) (p < 0.001). At 12 months, the mean V'maxFRC (Z score) was higher for children initially treated with HFOV (n = 15), as compared with children treated with conventional mechanical ventilation (n = 16): mean (95% confidence interval) difference was 0.6 (0.2-1.0) (p = 0.008). We conclude that very low birth weight infants with CLD have decreased V'maxFRC that worsen during the first year of life. Initial treatment with HFOV was associated with a more favorable outcome of V'maxFRC at 12 months corrected age.