Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study

Parthasarathy, Anand; Weber, Erica L.; Richards, Lisa; Fox, Douglas J.; Dunn, Andrew K.

doi:10.1117/1.3526368

Cited by 123 publications

(118 citation statements)

References 28 publications

(35 reference statements)

Supporting

Mentioning

116

Contrasting

Order By: Relevance

“…11,17,22 By use of a wide field laser Doppler imaging setup mounted to a neurosurgical microscope, changes in the perfusion of the cortex caused by finger tapping in an awake patient have been demonstrated. 22 In a few patients, the feasibility of imaging general brain perfusion by using laser speckle imaging was also shown.…”

Section: Discussionmentioning

confidence: 99%

“…22 In a few patients, the feasibility of imaging general brain perfusion by using laser speckle imaging was also shown. 11,17 However, both methods need an additional laser source integrated into the surgical microscope, which increases complexity of the imaging setup and requires additional expenditure for the medical approval by regulatory boards. Instead, optical imaging can easily be performed by using a standard surgical microscope.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery

Sobottka

Meyer

Kirsch

et al. 2013

JNS

View full text Add to dashboard Cite

Object Intraoperative optical imaging (IOI) is an experimental technique used for visualizing functional brain areas after surgical exposure of the cerebral cortex. This technique identifies areas of local changes in blood volume and oxygenation caused by stimulation of specific brain functions. The authors describe a new IOI method, including innovative data analysis, that can facilitate intraoperative functional imaging on a routine basis. To evaluate the reliability and validity of this approach, they used the new IOI method to demonstrate visualization of the median nerve area of the somatosensory cortex. Methods In 41 patients with tumor lesions adjacent to the postcentral gyrus, lesions were surgically removed by using IOI during stimulation of the contralateral median nerve. Optical properties of the cortical tissue were measured with a sensitive camera system connected to a surgical microscope. Imaging was performed by using 9 cycles of alternating prolonged stimulation and rest periods of 30 seconds. Intraoperative optical imaging was based on blood volume changes detected by using a filter at an isosbestic wavelength (λ = 568 nm). A spectral analysis algorithm was used to improve computation of the activity maps. Movement artifacts were compensated for by an elastic registration algorithm. For validation, intraoperative conduction of the phase reversal over the central sulcus and postoperative evaluation of the craniotomy site were used. Results The new method and analysis enabled significant differentiation (p < 0.005) between functional and nonfunctional tissue. The identification and visualization of functionally intact somatosensory cortex was highly reliable; sensitivity was 94.4% and specificity was almost 100%. The surgeon was provided with a 2D high-resolution activity map within 12 minutes. No method-related side effects occurred in any of the 41 patients. Conclusions The authors' new approach makes IOI a contact-free and label-free optical technique that can be used safely in a routine clinical setup. Intraoperative optical imaging can be used as an alternative to other methods for the identification of sensory cortex areas and offers the added benefit of a high-resolution map of functional activity. It has great potential for visualizing and monitoring additional specific functional brain areas such as the visual, motor, and speech cortex. A prospective national multicenter clinical trial is currently being planned.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery

Sobottka

Meyer

Kirsch

et al. 2013

JNS

View full text Add to dashboard Cite

show abstract

“…Beyond bench-side physiological research, there are direct implications for prognostic, diagnostic, and intraoperative imaging applications, as speckle imaging of microcirculatory flows is increasingly becoming applied for gauging local and systemic tissue health [8,9]. Consequently, laser speckle flowmetry studies are expanding in dermatological [10][11][12][13][14], ophthalmological [15][16][17], and neurosurgical settings [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Optimization of camera exposure durations for multi-exposure speckle imaging of the microcirculation

Kazmi

Balial

Dunn

2014

Biomed. Opt. Express

Self Cite

View full text Add to dashboard Cite

Improved Laser Speckle Contrast Imaging (LSCI) blood flow analyses that incorporate inverse models of the underlying laser-tissue interaction have been used to develop more quantitative implementations of speckle flowmetry such as Multi-Exposure Speckle Imaging (MESI). In this paper, we determine the optimal camera exposure durations required for obtaining flow information with comparable accuracy with the prevailing MESI implementation utilized in recent in vivo rodent studies. A looping leave-one-out (LOO) algorithm was used to identify exposure subsets which were analyzed for accuracy against flows obtained from analysis with the original full exposure set over 9 animals comprising n = 314 regional flow measurements. From the 15 original exposures, 6 exposures were found using the LOO process to provide comparable accuracy, defined as being no more than 10% deviant, with the original flow measurements. The optimal subset of exposures provides a basis set of camera durations for speckle flowmetry studies of the microcirculation and confers a twofold faster acquisition rate and a 28% reduction in processing time without sacrificing accuracy. Additionally, the optimization process can be used to identify further reductions in the exposure subsets for tailoring imaging over less expansive flow distributions to enable even faster imaging.

show abstract

“…[1][2][3][4] More recently, LSCI has been applied in studies of human patients. 5,6 While the high-resolution maps of relative changes in blood flow acquired during LSCI have been well validated, flow estimates from LSCI are affected by a number of parameters unrelated to blood flow. As such, the exact quantitative relationship between speckle contrast and blood flow velocity has not been precisely defined.…”

mentioning

confidence: 99%

Improved Cerebral Blood Flow Measurement with Multiexposure Speckle Imaging

Winship

2013

J Cereb Blood Flow Metab

View full text Add to dashboard Cite

Laser speckle contrast imaging (LSCI) is a powerful tool for in vivo imaging of blood flow dynamics. Based on the blurring of the random interference pattern ('speckle') produced at the camera by laser light reflecting off a surface, LSCI has been rapidly adopted because of its high spatial and temporal resolution coupled with the relative simplicity and low cost of assembling a LSCI instrument. Wide-field maps of cerebral blood flow acquired via LSCI have made significant contributions to our understanding of cerebral hemodynamics in the healthy and ischemic brain in animal models. [1][2][3][4] More recently, LSCI has been applied in studies of human patients. 5,6 While the high-resolution maps of relative changes in blood flow acquired during LSCI have been well validated, flow estimates from LSCI are affected by a number of parameters unrelated to blood flow. As such, the exact quantitative relationship between speckle contrast and blood flow velocity has not been precisely defined. 7,8 The sensitivity of LSCI to nonflow parameters is particularly problematic in long-term studies where nonflow parameters are more likely to vary between imaging sessions.Recently, traditional single-exposure LSCI was extended with a multiexposure speckle imaging (MESI) protocol that improved quantitative accuracy in microfluidic flow simulations and in vivo imaging in rodents. 9,10 Using improved mathematical models and instrumentation to acquire speckle contrast images at multiple, defined exposures, MESI accurately estimates flow changes associated during acute ischemic stroke, contrary to the underestimates of flow changes associated with traditional single-exposure LSCI. 10 However, the utility of MESI in long-term, repeated-imaging studies has not been validated.In the current issue, Kazmi et al 11 perform MESI in mice implanted with chronic cranial imaging windows. Multiexposure speckle imaging data are compared with quantitative measurements of absolute blood flow acquired via high-frame rate red blood cell photography (RBC tracking). In healthy mice and mice with targeted ischemic strokes imaged over multiple days, MESI consistently quantified blood flow more accurately than singleexposure LSCI. Notably, by testing multiple exposure times, Kazmi et al demonstrated that no single exposure time was optimal in all animals and imaging sessions. By incorporating multiple exposure times and improved mathematical modeling, MESI better accounted for variations in imaging conditions and more reliably quantified the blood flow during chronic imaging. Improved quantitative accuracy is demonstrated by reduced deviation between flow measurements derived from MESI and RBC tracking (B10%) relative to single-exposure LSCI and RBC tracking (B24%).While the reliability of quantitative accuracy between animal comparisons remains to be confirmed, MESI significantly improves the quantitative accuracy of LSCI blood flow measurements in both acute and chronic imaging paradigms. This improved quantitative accuracy extends LSCI beyond qualitati...

show abstract

Laser speckle contrast imaging of cerebral blood flow in humans during neurosurgery: a pilot clinical study

Cited by 123 publications

References 28 publications

Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery

Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery

Optimization of camera exposure durations for multi-exposure speckle imaging of the microcirculation

Improved Cerebral Blood Flow Measurement with Multiexposure Speckle Imaging

Contact Info

Product

Resources

About