Vision of the future: initial experience with intraoperative real-time high-resolution dynamic infrared imaging

2002 ◽  
Vol 97 (6) ◽  
pp. 1460-1471 ◽  
Author(s):  
Robert D. Ecker ◽  
Stephan J. Goerss ◽  
Fredric B. Meyer ◽  
Aaron A. Cohen-Gadol ◽  
Jeffrey W. Britton ◽  
...  
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Infrared Imaging ◽  
Intraoperative Imaging ◽  
Initial Experience ◽  
Cerebral Vessel ◽  
Content Type ◽  
Bypass Patency ◽  
Neurosurgical Patients ◽  
Fine Print

✓ High-resolution dynamic infrared (DIR) imaging provides intraoperative real-time physiological, anatomical, and pathological information; however, DIR imaging has rarely been used in neurosurgical patients. The authors report on their initial experience with intraoperative DIR imaging in 30 such patients. A novel, long-wave (8–10 µm), narrow-band, focal-plane-array infrared photodetector was incorporated into a camera system with a temperature resolution of 0.006°C, providing 65,000 pixels/frame at a data acquisition rate of 200 frames/second. Intraoperative imaging of patients was performed before and after surgery. Infrared data were subsequently analyzed by examining absolute differences in cortical temperatures, changes in temperature over time, and infrared intensities at varying physiological frequencies. Dynamic infrared imaging was applied in a variety of neurosurgical cases. After resection of an arteriovenous malformation, there was postoperative hyperperfusion of the surrounding brain parenchyma, which was consistent with a loss of autoregulation. Bypass patency and increased perfusion of adjacent brain were documented during two of three extracranial—intracranial bypasses. In seven of nine patients with epilepsy the results of DIR imaging corresponded to seizure foci that had been electrocorticographically mapped preoperatively. Dynamic infrared imaging demonstrated the functional cortex in four of nine patients undergoing awake resection and cortical stimulation. Finally, DIR imaging exhibited the distinct thermal footprints of 14 of 16 brain tumors. Dynamic infrared imaging may prove to be a powerful adjunctive intraoperative diagnostic tool in the neurosurgical imaging armamentarium. Real-time assessment of cerebral vessel patency and cerebral perfusion are the most direct applications of this technology. Uses of this imaging modality in the localization of epileptic foci, identification of functional cortex during awake craniotomy, and determination of tumor border and intraoperative brain shift are avenues of inquiry that require further investigation.

Real-time detection of vascular occlusion and reperfusion of the brain during surgery by using infrared imaging

2002 ◽  
Vol 96 (5) ◽  
pp. 918-923 ◽  
Author(s):  
Joseph C. Watson ◽  
Alexander M. Gorbach ◽  
Ryszard M. Pluta ◽  
Ramin Rak ◽  
John D. Heiss ◽  
...  
Keyword(s):  
Blood Flow ◽  
High Resolution ◽  
Real Time ◽  
Infrared Imaging ◽  
Cerebral Arteries ◽  
Infrared Camera ◽  
Collateral Flow ◽  
Content Type ◽  
The Brain ◽  
Fine Print

Object. Application of sensitive infrared imaging is ideally suited to observe blood vessels and blood flow in exposed organs, including the brain. Temporary vascular occlusion is an important part of neurosurgery, but the capacity to monitor the effects of these occlusions in real time is limited. In surgical procedures that require vascular manipulation, such as those involving aneurysms, arteriovenous malformations (AVMs), or tumors, the ability to visualize blood flow in vessels and their distribution beds would be beneficial. The authors recount their experience in the use of a sensitive (0.02°C), high-resolution (up to 50 µm/pixel) infrared camera with a rapid shutter speed (up to 2 msec/frame) for localizing cortical function intraoperatively. They observed high-resolution images of cerebral arteries and veins. The authors hypothesized that infrared imaging of cerebral arteries, performed using a sensitive, high-resolution camera during surgery, would permit changes in arterial flow to be be seen immediately, thus providing real-time assessment of brain perfusion in the involved vascular territory. Methods. Cynomolgus monkeys underwent extensive craniectomies, exposing the frontal, parietal, and temporal lobes. Temporary occlusions of the internal carotid artery and middle cerebral artery branches (30 events) were performed serially and were visualized with the aid of an infrared camera. Arteries and veins of the monkey brain were clearly visualized due to cooling of the exposed brain, which contrasted with blood within the vessels that remained at core temperature. Blood flow changes in vessels were seen immediately (< 1 second) in real time during occlusion and reopening of the vessels, regardless of the duration of the occlusion. Areas of decreased cortical blood flow rapidly cooled (−0.3 to 1.3°C) and reheated in response to reperfusion. Rewarming occurred faster in arteries than in the cortex (for a 20-minute occlusion, the change in temperature per second was 2 × 10−2°C in the artery and 7 × 10−3°C in the brain). Collateral flow could be evaluated by intraoperative observations and data processing. Conclusions. Use of high-resolution, digital infrared imaging permits real-time visualization of arterial flow. It has the potential to provide the surgeon with a means to assess collateral flow during temporary vessel occlusion and to visualize directly the flow in parent arteries or persistent filling of an aneurysm after clipping. During surgery for AVMs, the technique may provide a new way to assess arterial inflow, venous outflow, results of embolization, collateral flow, steal, and normal perfusion pressure breakthrough.

Stent-assisted angioplasty of intracranial vertebrobasilar atherosclerosis: an initial experience

2000 ◽  
Vol 92 (5) ◽  
pp. 771-778 ◽  
Author(s):  
Peter A. Rasmussen ◽  
John Perl ◽  
John D. Barr ◽  
Georges Z. Markarian ◽  
Irene Katzan ◽  
...  
Keyword(s):  
Alternative Therapy ◽  
Signs And Symptoms ◽  
Antiplatelet Agents ◽  
Posterior Circulation ◽  
Occlusive Disease ◽  
Stent Insertion ◽  
Initial Experience ◽  
Content Type ◽  
Vertebrobasilar Artery ◽  
Fine Print

Object. Patients with intracranial vertebrobasilar artery (VBA) atherosclerotic occlusive disease have few therapeutic options. Unfortunately, VBA transient ischemic attacks (TIAs) herald a lethal or devastating event within 5 years in 25 to 30% of patients. The authors report their initial experience with eight patients in whom medically refractory TIAs secondary to intracranial posterior circulation atherosclerotic occlusive lesions were treated with stent-assisted angioplasty.Methods. Eight patients (six men), ranging in age from 43 to 77 years, experienced signs and symptoms of VBA insufficiency despite combination therapy with warfarin and antiplatelet agents. Angiographic studies revealed severe distal vertebral (four patients), proximal basilar (one patient), or proximal and midbasilar stenoses (three patients). Aspirin and clopidogrel were administered for 3 days before primary angioplasty and stent placement, and this regimen was maintained by the patients on discharge. Patients underwent heparinization during the procedure and were given a bolus and 12-hour infusion of abciximab. A neurologist specializing in stroke evaluated all patients before and after the procedure.The VBAs in all patients were successfully revascularized with 7 to 28% residual stenosis. Six patients experienced no neurological complications. One patient died the evening of the procedure due to a massive subarachnoid hemorrhage. Two patients had groin hematomas, one developed congestive heart failure, and one had transient encephalopathy. All surviving patients are asymptomatic up to 8 months postoperatively.Conclusions. Although primary intracranial VBA angioplasty with stent insertion is technically feasible, complications associated with the procedure can be life threatening. As experience is gained with this procedure, it may be offered routinely as an alternative therapy to patients with medically refractory posterior circulation occlusive disease that may develop into catastrophic VBA insufficiency.

A framework for near real-time ROM stockpile modelling to improve blending efficiency

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shi Zhao ◽  
Tien-Fu Lu ◽  
Larissa Statsenko ◽  
Benjamin Koch ◽  
Chris Garcia
Keyword(s):  
High Resolution ◽  
Real Time ◽  
Laser Scanning ◽  
High Efficiency ◽  
Reference Model ◽  
Geometric Model ◽  
Mining Industry ◽  
Management Systems ◽  
Content Type ◽  
Ore Grade

Purpose In the mining industry, a run-of-mine (ROM) stockpile is a temporary storage unit, but it is also widely accepted as an effective method to reduce the short-term variations of ore grade. However, tracing ore grade at ROM stockpiles accurately using most current fleet management systems is challenging, due to insufficient information available in real time. This study aims to build a three-dimensional (3D) model for ROM stockpiles continuously based on fine-grained grade information through integrating data from a number of ore grade tracking sources. Design/methodology/approach Following a literature review, a framework for a new stockpile management system is proposed. In this system, near real-time high-resolution 3D ROM stockpile models are created based on dump/load locations measured from global positioning system sensors. Each stockpile model contains a group of layers which are separated by different qualities. Findings Acquiring the geometric shapes of all the layers in a stockpile and cuts made by front wheel loaders provides a better understanding about the quality and quality distribution within a stockpile when it is stacked/reclaimed. Such a ROM stockpile model can provide information on predicating ore blend quality with high accuracy and high efficiency. Furthermore, a 3D stockyard model created based on such ROM stockpile models can help organisations optimise material flow and reduce the cost. Research limitations/implications The modelling algorithm is evaluated using a laboratory scaled stockpile at this stage. The authors expect to scan a real stockpile and create a reference model from it. Meanwhile, the geometric model cannot represent slump or collapse during reclaiming faithfully. Therefore, the model is expected to be reconcile monthly using laser scanning data. Practical implications The proposed model is currently translated to the operations at OZ Minerals. The use of such model will reduce the handling costs and improve the efficiency of existing grade management systems in the mining industry. Originality/value This study provides a solution to build a near real-time high-resolution multi-layered 3D stockpile model through using currently available information and resources. Such novel and low-cost stockpile model will improve the production rates with good output product quality control.

Systemic candidiasis and endophthalmitis in neurosurgical patients

1976 ◽  
Vol 45 (1) ◽  
pp. 95-97 ◽  
Author(s):  
Arthur R. Cushman ◽  
Gerald Friedman ◽  
John Capsavage
Keyword(s):  
Broad Spectrum ◽  
Opportunistic Infections ◽  
Systemic Candidiasis ◽  
High Susceptibility ◽  
Content Type ◽  
Broad Spectrum Antibiotics ◽  
Neurosurgical Patients ◽  
Fine Print

✓ Three cases of systemic candidiasis in neurosurgical patients are presented. Two of the three patients also had endophthalmitis. All of the cases were treated with broad-spectrum antibiotics and glucocorticoids prior to the appearance of candidiasis. The authors stress the high susceptibility of neurosurgical patients to opportunistic infections of this type.

The physiopathology of respiration in neurosurgical patients

1979 ◽  
Vol 50 (6) ◽  
pp. 699-714 ◽  
Author(s):  
Elizabeth A. M. Frost
Keyword(s):  
Spinal Cord Injuries ◽  
Pediatric Neurosurgery ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Regulation Of Respiration ◽  
Content Type ◽  
Neurosurgical Patients ◽  
Cord Injury ◽  
Injured Patients ◽  
Fine Print

✓ Regulation of respiration is summarized as to peripheral and central chemoreceptors, controllers of voluntary and automatic respiration, and stimulators (CO2, O2, and pH). The information that may be obtained from blood-gas analysis is reviewed and basic problems in acid-base imbalance described. Commonly employed respiratory patterns are discussed. Preoperative pulmonary assessment necessary in elective intracranial situations, spinal cord injuries, and pediatric neurosurgery is outlined. Some of the special problems of the patient with multiple trauma, including injury to the central nervous system are reviewed. Central and peripheral factors that cause respiratory difficulty in head-injured patients are tabulated, and an outline is given of diagnosis and therapy. There are many possible causes of intraoperative hypoxia and hypercarbia, and these complications with their prevention or treatment are examined. Criteria for extubation are established. Finally, postoperative pulmonary care in elective, emergency, and cord injury situations is discussed. The key to successful perioperative pulmonary care of the neurosurgical patient requires close cooperation between the neurosurgeon and anesthesiologist.

Extracranial-intracranial arterial bypass for middle cerebral artery stenosis and occlusion

1985 ◽  
Vol 62 (6) ◽  
pp. 831-838 ◽  
Author(s):  
Brian T. Andrews ◽  
Norman L. Chater ◽  
Philip R. Weinstein
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Slight Reduction ◽  
Content Type ◽  
Perioperative Stroke ◽  
Arterial Bypass ◽  
Mca Occlusion ◽  
Bypass Patency ◽  
Completed Stroke ◽  
Fine Print

✓ Forty-seven patients with middle cerebral artery (MCA) stenosis and 18 patients with MCA occlusion underwent extracranial-intracranial arterial bypass procedures. Patients presented with a history of transient ischemic attacks (TIA's), reversible ischemic neurological deficits, TIA's after initial stroke, stroke-in-evolution, or completed stroke. Angiography revealed that the MCA stenosis ranged from 70% to over 95%. Two patients (4.3%) in the stenosis group had a perioperative stroke (within 30 days of operation). There was no perioperative mortality. In the occlusion group, no patient had a perioperative stroke, and one patient (5.5%) died from a non-neurological disease. The TIA's resolved completely in 90% of the patients with stenosis and in 91.6% of those with occlusion. No patient with MCA stenosis had a late ipsilateral stroke, although five had a contralateral or vertebrobasilar stroke. One patient with MCA occlusion had a late ipsilateral stroke. The bypass patency rate at late follow-up review was 100%. The results of intracranial-extracranial arterial bypass procedures appear to be similar for patients with either stenosis or occlusion of the MCA. Symptomatic relief of TIA's was excellent and, in two patients with progressive stroke-in-evolution, the deficit was stabilized. The incidence of postoperative ipsilateral stroke was low in patients with TIA's alone or with TIA's after an initial stroke, but among patients with completed stroke, improvement was confined to slight reduction in the neurological deficit.

Neurosurgical hyponatremia: the role of inappropriate antidiuresis

1971 ◽  
Vol 34 (4) ◽  
pp. 506-514 ◽  
Author(s):  
John L. Fox ◽  
Joel L. Falik ◽  
Robert J. Shalhoub
Keyword(s):  
Differential Diagnosis ◽  
Sodium Concentration ◽  
Fluid Restriction ◽  
Urine Sodium ◽  
Content Type ◽  
Inappropriate Secretion ◽  
Neurosurgical Patients ◽  
Inappropriate Antidiuresis ◽  
Fine Print

✓ Of 80 consecutive neurosurgical patients, 23 exhibited inappropriate secretion of the antidiuretic hormone (ISADH); 11 of these patients required marked fluid restriction. Sodium concentration in the urine characteristically increased as serum values decreased. Only by following the urine sodium concentrations could the differential diagnosis of nutritional hyponatremia and ISADH be made. The role of ISADH in cerebral edema is stressed. The treatment recommended for ISADH is marked fluid restriction, whereas in nutritional hyponatremia, saline replacement is indicated.

High-resolution three-dimensional T2-weighted sequence for neuronavigation: a new setup and clinical trial

2005 ◽  
Vol 102 (4) ◽  
pp. 658-663 ◽  
Author(s):  
Jan Gralla ◽  
Raphael Guzman ◽  
Caspar Brekenfeld ◽  
Luca Remonda ◽  
Claus Kiefer
Keyword(s):  
Clinical Trial ◽  
High Resolution ◽  
Clinical Application ◽  
Three Dimensional ◽  
Whole Body ◽  
Low Grade ◽  
Data Set ◽  
Content Type ◽  
Image Guided ◽  
Fine Print

Object. Conventional imaging for neuronavigation is performed using high-resolution computerized tomography (CT) scanning or a T1-weighted isovoxel magnetic resonance (MR) sequence. The extension of some lesions, however, is depicted much better on T2-weighted MR images. A possible fusion process used to match low-resolution T2-weighted MR image set with a referenced CT or T1-weighted data set leads to poor resolution in the three-dimensional (3D) reconstruction and decreases accuracy, which is unacceptable for neuronavigation. The object of this work was to develop a 3D T2-weighted isovoxel sequence (3D turbo—spin echo [TSE]) for image-guided neuronavigation of the whole brain and to evaluate its clinical application. Methods. The authors performed a phantom study and a clinical trial on a newly developed T2-weighted isovoxel sequence, 3D TSE, for image-guided neuronavigation using a common 1.5-tesla MR imager (Siemens Sonata whole-body imager). The accuracy study and intraoperative image guidance were performed with the aid of the pointer-based Medtronic Stealth Station Treon. The 3D TSE data set was easily applied to the navigational setup and demonstrated a high registration accuracy during the experimental trial and during an initial prospective clinical trial in 25 patients. The sequence displayed common disposable skin fiducial markers and provided convincing delineation of lesions that appear hyperintense on T2-weighted images such as low-grade gliomas and cavernomas in its clinical application. Conclusions. Three-dimensional TSE imaging broadens the spectrum of navigational and intraoperative data sets, especially for lesions that appear hyperintense on T2-weighted images. The accuracy of its registration is very reliable and it enables high-resolution reconstruction in any orientation, maintaining the advantages of image-guided surgery.

Methylprednisolone half-life during simultaneous barbiturate treatment and mechanical hyperventilation of neurosurgical patients

1985 ◽  
Vol 62 (2) ◽  
pp. 182-185 ◽  
Author(s):  
Jørgen Gabrielsen ◽  
Asger Bendtsen ◽  
Henrik Eriksen ◽  
Steen Andersen
Keyword(s):  
Enzyme Induction ◽  
Half Life ◽  
Marked Reduction ◽  
Sodium Succinate ◽  
Steroid Treatment ◽  
Blood Samples ◽  
Content Type ◽  
Methylprednisolone Sodium Succinate ◽  
Neurosurgical Patients ◽  
Fine Print

✓ The pharmacokinetics of methylprednisolone sodium succinate (MP) were studied in six neurosurgical patients under intensive treatment with large doses of MP, barbiturates, and mechanical hyperventilation. The study showed a remarkable level of enzyme induction within 24 hours after starting treatment, when the first blood samples were taken. The half-life (t½) for MP during barbiturate and hyperventilation therapy was found to be reduced by a mean 55% (p < 0.01) in relation to the t½ of MP when administered alone. Studies on the day after termination of barbiturate intake indicated a tendency for an increase in the t½ of MP, but it was not significantly different from the pretermination assessment (p > 0.05). On the basis of this study it is not possible to determine if the change in t½ alone is governed by enzyme induction or by a combination of this plus a change in the distribution and clearance of the steroid. The clinical implication of these findings is that patients who are undergoing steroid treatment and at the same time are sedated with barbiturates should have their MP dose increased in order to compensate for the marked reduction of t½ of MP.

Intraoperative magnetic resonance imaging during transsphenoidal surgery

2001 ◽  
Vol 95 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Rudolf Fahlbusch ◽  
Oliver Ganslandt ◽  
Michael Buchfelder ◽  
Werner Schott ◽  
Christopher Nimsky
Keyword(s):  
Magnetic Resonance ◽  
Mr Imaging ◽  
Early Stage ◽  
Intraoperative Imaging ◽  
Tumor Resection ◽  
Tumor Removal ◽  
Content Type ◽  
Early Evaluation ◽  
Flexible Coil ◽  
Fine Print

Object. The aim of this study was to evaluate whether intraoperative magnetic resonance (MR) imaging can increase the efficacy of transsphenoidal microsurgery, primarily in non—hormone-secreting intra- and suprasellar pituitary macroadenomas. Methods. Intraoperative imaging was performed using a 0.2-tesla MR imager, which was located in a specially designed operating room. The patient was placed supine on the sliding table of the MR imager, with the head placed near the 5-gauss line. A standard flexible coil was placed around the patient's forehead. Microsurgery was performed using MR-compatible instruments. Image acquisition was started after the sliding table had been moved into the center of the magnet. Coronal and sagittal T1-weighted images each required over 8 minutes to acquire, and T2-weighted images were obtained optionally. To assess the reliability of intraoperative evaluation of tumor resection, the intraoperative findings were compared with those on conventional postoperative 1.5-tesla MR images, which were obtained 2 to 3 months after surgery. Among 44 patients with large intra- and suprasellar pituitary adenomas that were mainly hormonally inactive, intraoperative MR imaging allowed an ultra-early evaluation of tumor resection in 73% of cases; such an evaluation is normally only possible 2 to 3 months after surgery. A second intraoperative examination of 24 patients for suspected tumor remnants led to additional resection in 15 patients (34%). Conclusions. Intraoperative MR imaging undoubtedly offers the option of a second look within the same surgical procedure, if incomplete tumor resection is suspected. Thus, the rate of procedures during which complete tumor removal is achieved can be improved. Furthermore, additional treatments for those patients in whom tumor removal was incomplete can be planned at an early stage, namely just after surgery.

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