scholarly journals Optical Brain Biopsy with a Fluorescence and Vessel Tracing Probe

2021 ◽  
Author(s):  
Johan Richter ◽  
Neda Haj-Hosseini ◽  
Peter Milos ◽  
Martin Hallbeck ◽  
Karin Wårdell
Keyword(s):  
Blood Flow ◽  
Brain Biopsy ◽  
Final Diagnosis ◽  
Optical Measurements ◽  
Microvascular Blood Flow ◽  
Doppler Flowmetry ◽  
Stereotactic System ◽  
Clinical Benefits ◽  
Risk Of Hemorrhage ◽  
Stereotactic Biopsies

Abstract BACKGROUND Accurate stereotactic biopsies of brain tumors are imperative for diagnosis and tailoring of the therapy. Repetitive needle insertions enhance risks of brain lesioning, hemorrhage, and complications due to prolonged procedure. OBJECTIVE To investigate clinical benefits of a combined 5-aminolaevulinic acid (5-ALA) fluorescence and laser Doppler flowmetry system for the detection of malignant brain tumor and blood vessels in stereotactic biopsies. METHODS Planning of targets and trajectories was followed by optical measurements in 20 patients, using the Leksell Stereotactic System and a manual insertion device. Fluorescence spectra, microvascular blood flow, and tissue grayness were recorded each millimeter along the paths. Biopsies were taken at preplanned positions. The diagnoses were compared with the fluorescence signals. The recordings were plotted against measurement positions and compared. Sites indicating a risk of hemorrhage were counted as well as the time for the procedures. RESULTS Signals were recorded along 28 trajectories, and 78 biopsies were collected. The final diagnosis showed 17 glioblastomas, 2 lymphomas, and 1 astrocytoma grade III. Fluorescence was seen along 23 of the paths with 4 having the peak of 5-ALA fluorescence 3 mm or more from the precalculated target. There was increased microcirculation in 40 of 905 measured positions. The measurement time for each trajectory was 5 to 10 min. CONCLUSION The probe provided direct feedback of increased blood flow along the trajectory and of malignant tissue in the vicinity of the target. The method can increase the precision and the safety of the biopsy procedure and reduce time.

scholarly journals Prognosis criteria of the severe postembolization syndrome in patients with uterine myoma

2020 ◽  
pp. 67-74
Author(s):  
E.T. Nurmukhametova ◽  
M.E. Shlyapnikov
Keyword(s):  
Blood Flow ◽  
Uterine Myoma ◽  
Microvascular Blood Flow ◽  
Timely Initiation ◽  
Adequate Treatment ◽  
Doppler Flowmetry ◽  
Occlusion Test ◽  
Prognostic Criteria ◽  
Flow Reserve ◽  
Postembolization Syndrome

Recently specialists take an interest in organ-preserving methods of uterine fibroids treatment, one of which is uterine artery embolization (UAE). One of the method’s negative aspects is the severe postembolization syndrome (PES) development, requiring timely initiation of adequate treatment in order to avoid severe complications that could lead to the organ removal. The study was aimed to search for the prognostic criteria of the severe PES development during the preoperative period. The study included 81 UAE-treated women aged 19–50 with 7–17 week uterine myoma. The patients’ anthropometric measurements were used, as well as the skin microcirculation data obtained by laser Doppler flowmetry together with the occlusion test. Based on prognostic criteria, models with AUC (area under ROC curve) > 0.8 were presented. According to the models, the anthropometric predictors of the severe PES were the following: age under 38.5 (p < 0.05); BMI lower than 25 kg/m2 (р < 0.05), and microcirculation value (M) prior to UAE below 9.55 PU (р = 0.001). Microvascular blood flow during the occlusion test indicate that the higher the oxygen consumption index (I), intravascular resistance (Rc), capillary blood flow reserve capacity in the models, the higher the risk of the severe PES development (p < 0.05). Low alpha angle value obtained by the occlusion test (p = 0.003) as well as the UVLF value (p = 0.004) in the models also indicate the increased risk of severe PES. Multidimensional prognostic modelling admits to expect the severe PES development prior to UAE, which allows the doctor to prepare the woman for specific management and treatment.

Measurement of hepatic blood flow after severe hemorrhage: lack of restoration despite adequate resuscitation

1992 ◽  
Vol 262 (1) ◽  
pp. G92-G98 ◽  
Author(s):  
P. Wang ◽  
Z. F. Ba ◽  
J. Burkhardt ◽  
I. H. Chaudry
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Hemorrhagic Shock ◽  
Hepatic Blood Flow ◽  
Microvascular Blood Flow ◽  
Midline Laparotomy ◽  
Doppler Flowmetry ◽  
Severe Hemorrhage ◽  
Icg Clearance

Although Ringer lactate (RL) is routinely used for resuscitation, it is not known whether the volume of RL that restores cardiac output after severe hemorrhagic shock also restores the depressed effective hepatic blood flow (EHBF). To study this, a 5-cm midline laparotomy was performed in rats (i.e., trauma induced), and the animals were then bled to and maintained at a mean arterial pressure of 40 mmHg until 40% of maximum bleedout volume was returned in the form of RL. Animals were then resuscitated with four or five times the volume of maximum bleedout with RL. EHBF was determined during hemorrhage and at various intervals thereafter by an in vivo indocyanine green (ICG) clearance technique and corrected by the appropriate hepatic extraction ratio for ICG. Cardiac output was determined by ICG dilution, and hepatic microvascular blood flow (HMBF) was measured with laser Doppler flowmetry. In addition, hepatic blood flow was assessed by using radioactive microspheres. Results indicate that resuscitation markedly improved but did not restore the depressed EHBF after trauma and hemorrhagic shock despite the fact that cardiac output was restored. Similar changes in EHBF, HMBF, and hepatic blood flow as determined by microspheres were observed, suggesting that the in vivo ICG clearance is a reliable method to assess effective hepatic perfusion. Thus the lack of restoration of EHBF may be responsible for the subsequent hepatocellular dysfunction after trauma and severe hemorrhage.

Validation of laser-Doppler flowmetry in measurement of spinal cord blood flow

1989 ◽  
Vol 257 (2) ◽  
pp. H674-H680 ◽  
Author(s):  
P. J. Lindsberg ◽  
J. T. O'Neill ◽  
I. A. Paakkari ◽  
J. M. Hallenbeck ◽  
G. Feuerstein
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Laser Doppler Flowmetry ◽  
Laser Doppler ◽  
Microvascular Blood Flow ◽  
Base Line ◽  
Spinal Cord Blood Flow ◽  
Flow Measurements ◽  
Doppler Flowmetry

Laser-Doppler flowmetry (LDF) is a non-invasive method for continuous on-line monitoring of microvascular blood flow. LDF has previously been validated with established methods in various tissues, yet its validity and resolution in the central nervous system (CNS) remain unclear. We compared LDF with the microsphere method (MS) using two independent laser probes placed on the dorsal lumbar spinal cord (L5 laminectomy) of anesthetized rabbits (n = 9). After base-line flow measurements, spinal cord blood flow (SCBF) was increased (up to 50%) with phenylephrine (10-80 micrograms.kg-1.min-1 iv) and decreased (up to 50%) with chlorisondamine (10 mg/kg iv) or other stimuli. The percentage changes of lumbar SCBF and vascular resistance (VR) from the base line obtained by LDF and MS excellently agreed (rBF = 0.86, rVR = 0.94, P less than 0.0001). LDF estimated also the absolute SCBF values parallel to MS (r = 0.77, P less than 0.001). In conclusion, the validity of LDF in estimating the SCBF and dynamic changes of BF and VR is confirmed. Therefore, LDF may prove useful for monitoring CNS microcirculation in normal or pathophysiological states.

Role of nitric oxide in vasodilator response induced by salbutamol in rat diaphragmatic microcirculation

1997 ◽  
Vol 272 (5) ◽  
pp. H2173-H2179 ◽  
Author(s):  
H. Y. Chang
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cyclic Amp ◽  
Laser Doppler Flowmetry ◽  
Ringer Solution ◽  
Laser Doppler ◽  
Microvascular Blood Flow ◽  
Doppler Flowmetry ◽  
Vasodilator Response

To determine the contribution of nitric oxide (NO) to the vasodilator response induced by salbutamol in diaphragmatic microcirculation, we studied a diaphragmatic preparation in anesthetized rats. With bicarbonate-buffered Ringer solution continuously suffusing the diaphragm, laser-Doppler flowmetry was used to record microvascular blood flow (QLDF). The drugs were applied to the surface of the diaphragm. Salbutamol (3.2 x 10(-7)-10(-4) M), isoproterenol (3.2 x 10(-8)-3.2 x 10(-6) M), and forskolin (3.2 x 10(-7)-10(-5) M) each elicited a concentration-dependent increase in QLDF. The vasodilator response induced by salbutamol (3.2 x 10(-7), 10(-6), and 3.2 x 10(-6) M) was attenuated by a 15-min suffusion of N omega-nitro-L-arginine (L-NNA, 10(-4) M), and pretreatment with L-arginine (10(-2) M) could restore salbutamol-induced vasodilator responses. Salbutamol-induced vasodilation was also abolished by propranolol (10(-5) M). Similarly, the vasodilator response elicited by isoproterenol (3.2 x 10(-8), 10(-7), and 3.2 x 10(-7) M) and forskolin (3.2 x 10(-7), 10(-6), and 3.2 x 10(-6) M) was inhibited by L-NNA (10(-4) M). In contrast, the vasodilator response induced by adenosine (10(-6), 10(-5), and 10(-4) M) was not affected by L-NNA (10(-4) M). These data indicate that in rat diaphragmatic microcirculation salbutamol-induced vasodilation may be partly mediated by beta-adrenoceptors on the endothelium. Moreover, these data suggest that an elevation of cyclic AMP in the endothelium may cause release of NO.

scholarly journals Relationship Between Laser Doppler Signals and Anatomy During Deep Brain Stimulation Electrode Implantation Toward the Ventral Intermediate Nucleus and Subthalamic Nucleus

2012 ◽  
Vol 72 (2) ◽  
pp. ons127-ons140 ◽  
Author(s):  
Karin Wårdell ◽  
Peter Zsigmond ◽  
Johan Richter ◽  
Simone Hemm
Keyword(s):  
Blood Flow ◽  
Deep Brain Stimulation ◽  
Subthalamic Nucleus ◽  
Brain Stimulation ◽  
Laser Doppler ◽  
Optical Measurements ◽  
Microvascular Blood Flow ◽  
Intermediate Nucleus ◽  
Ventral Intermediate Nucleus ◽  
Deep Brain

Abstract BACKGROUND: Deep brain stimulation (DBS) requires precise and safe navigation to the chosen target. Optical measurements allow monitoring of gray-white tissue boundaries (total light intensity [TLI]) and microvascular blood flow during stereotactic procedures. OBJECTIVE: To establish the link between TLI/blood flow and anatomy along trajectories toward the ventral intermediate nucleus (Vim) and subthalamic nucleus (STN). METHODS: Stereotactic laser Doppler measurements were obtained with millimeter precision from the cortex toward the Vim (n = 13) and STN (n = 9). Optical trajectories of TLI and blood flow were created and compared with anatomy by superimposing the Schaltenbrandt-Wahren atlas on the patients' pre- and postoperative images. Measurements were divided into anatomic subgroups and compared statistically. RESULTS: Typical TLI trajectories with well-defined anatomic regions could be identified for the Vim and STN. TLI was significantly lower (P &lt; .001) and microvascular blood flow significantly higher (P = .01) in the Vim targets. Of 1285 sites, 38 showed blood flow peaks, 27 of them along the Vim trajectories. High blood flow was more common close to the sulci and in the vicinity of the caudate/putamen. Along 1 Vim trajectory, a slight bleeding was suspected during insertion of the probe and confirmed with postoperative computed tomography. CONCLUSION: Laser Doppler is useful for intraoperative guidance during DBS implantation because simultaneous measurement of tissue grayness and microvascular blood flow can be done along the trajectory with millimeter precision. Typical but different TLI trajectories were found for the Vim and STN.

Differential microvascular response to disuse in rat hindlimb skeletal muscles

1999 ◽  
Vol 87 (4) ◽  
pp. 1496-1505 ◽  
Author(s):  
Karel Tyml ◽  
Odile Mathieu-Costello ◽  
Linong Cheng ◽  
Earl G. Noble
Keyword(s):  
Blood Flow ◽  
Capillary Density ◽  
Medial Gastrocnemius ◽  
Microvascular Blood Flow ◽  
Specific Response ◽  
Muscle Control ◽  
Muscle Type ◽  
Cross Sectional ◽  
Doppler Flowmetry ◽  
Edl Muscle

The aim of the study was to address discrepant findings in the literature regarding coupling between decreased functional demand during disuse and reduced capillarity. We previously reported [K. Tyml, O. Mathieu-Costello, and E. Noble. Microvasc. Res. 49: 17–32, 1995] that severe disuse of rat extensor digitorum longus (EDL) muscle caused by a 2-wk application of tetrodotoxin (TTX) on the sciatic nerve is not accompanied by capillary loss. Using the same animal model, the present study examined whether this absence of coupling could be explained in terms of 1) too short a duration of disuse and 2) muscle-specific response to disuse. Fischer 344 rats were exposed to either no treatment (control) or to 2- or 8-wk TTX applications. Fiber size, capillary density per fiber cross-sectional area, and capillary-to-fiber (C/F) ratio were determined by morphometry in the EDL muscle (control, 2- and 8-wk groups) and in the superficial portion of medial gastrocnemius (Gas) muscle (control, 2 wk). In both muscles, microvascular blood flow was evaluated by intravital microscopy [red blood cell velocity in capillaries ( V RBC)] and by laser Doppler flowmetry (LDF). Regardless of duration of TTX application or muscle type, TTX-induced disuse resulted in a significant reduction of fiber area (44–71%). However, capillary density increased in EDL muscle (both at 2 and 8 wk) but not in Gas muscle. C/F ratio decreased in EDL muscle at 8 wk (18%) and in Gas muscle (39%). This indicates that the effect on capillarity depended on duration of disuse and on muscle type. V RBC and LDF signal were significantly larger in EDL than in Gas muscle. Analysis of change in capillarity vs. V RBC suggested that the outcome of disuse may be modulated by blood flow. We conclude that the duration of skeletal muscle disuse per se does not dictate capillary loss, and we hypothesize that discrepant findings of coupling between functional demand and capillarity could be due to the presence/absence of flow-related angiogenesis superimposed on the capillary removal process during disuse.

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