Transcranial ultrasonic propagation and enhanced brain imaging exploiting the focusing effect of the skull

2020 ◽  
Vol 39 (3) ◽  
pp. 671-682
Author(s):  
Stamatis A. Amanatiadis ◽  
Georgios K. Apostolidis ◽  
Chrysanthi S. Bekiari ◽  
Nikolaos V. Kantartzis
Keyword(s):  
Numerical Simulations ◽  
Acoustic Waves ◽  
Human Life ◽  
Virtual Source ◽  
Content Type ◽  
Focusing Effect ◽  
Wave Refraction ◽  
Ultrasonic Propagation ◽  
Transcranial Imaging ◽  
The Brain

Purpose The reliable transcranial imaging of brain inner structures for diagnostic purposes is deemed crucial owing to the decisive importance and contribution of the brain in human life. The purpose of this paper is to investigate the potential application of medical ultrasounds to transcranial imaging using advanced techniques, such as the total focussing method. Design/methodology/approach Initially, the fundamental details of the total focussing method are presented, while the skull properties, such as the increased acoustic velocity and scattering, are thoroughly examined. Although, these skull characteristics constitute the main drawback of typical transcranial ultrasonic propagation algorithms, they are exploited to focus the acoustic waves towards the brain. To this goal, a virtual source is designed, considering the wave refraction, to efficiently correct the reconstructed brain image. Finally, the verification of the novel method is conducted through numerical simulations of various realistic setups. Findings The theoretically designed virtual source resembles a focussed sensor; therefore, the directivity increment, owing to the propagation through the skull, is confirmed. Moreover, numerical simulations of real-world scenarios indicate that the typical artifacts of the conventional total focussing method are fully overcome because of the increased directivity of the proposed technique, while the reconstructed image is efficiently corrected when the proposed virtual source is used. Originality/value A new systematic methodology along with the design of a flexible virtual source is developed in this paper for the reliable and precise transcranial ultrasonic image reconstruction of the brain. Despite the slight degradation owing to the skull scattering, the combined application of the total focussing method and the featured virtual source can successfully detect arbitrary anomalies in the brain that cannot be spotted by conventional techniques.

Inverse thermal analysis of the neonatal brain cooling process

2014 ◽  
Vol 24 (4) ◽  
pp. 949-968 ◽  
Author(s):  
Joanna Łaszczyk ◽  
Anna Maczko ◽  
Wojciech Walas ◽  
Andrzej J. Nowak
Keyword(s):  
Numerical Simulations ◽  
Inverse Analysis ◽  
Least Square Method ◽  
Least Square ◽  
Bioheat Transfer ◽  
Brain Cooling ◽  
Bioheat Equation ◽  
Cooling Process ◽  
Content Type ◽  
The Brain

Purpose – This paper aims to test the inverse analysis, based on the standard least-square method, which will finally lead to find the appropriate parameters of modelling of the brain cooling process. Design/methodology/approach – To test the presented in this paper method of inverse analysis the numerical simulations of the bioheat transfer process in the neonatal body were performed. To model the bioheat transfer the Pennes bioheat equation and the modified Fiala model were applied. Findings – The performed tests of the inverse analysis proved that it is possible to estimate the proper parameters of the process using this tool, but always with the small mistake. Research limitations/implications – The presented method still requires a lot of tests. The test with the data from real measurements can be very valuable. Practical implications – The determination of the proper parameters of the bioheat transfer in the neonatal body can finally be used to perform the numerical simulations of the brain cooling process. Social implications – The performance of the numerical simulations of the brain cooling process in the proper way can finally helps protect newborns’ health and life. Originality/value – In the paper the attempt of the inverse analysis in order to determine the parameters of bioheat transfer in the newborn's body is made.

Long-term management of patients with multiple brain metastases after shaped beam radiosurgery

2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Tumor Control ◽  
Content Type ◽  
Negative Results ◽  
Multiple Metastases ◽  
Extracranial Disease ◽  
Successful Control ◽  
The Brain

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.

Radiosurgery for patients with recurrent small cell lung carcinoma metastatic to the brain: outcomes and prognostic factors

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 247-254 ◽  
Author(s):  
Jason Sheehan ◽  
Douglas Kondziolka ◽  
John Flickinger ◽  
L. Dade Lunsford
Keyword(s):  
Lung Cancer ◽  
Brain Metastases ◽  
Lung Carcinoma ◽  
Small Cell Lung Carcinoma ◽  
Small Cell ◽  
Small Cell Lung ◽  
Cell Lung Carcinoma ◽  
Content Type ◽  
The Brain ◽  
Fine Print

Object. Lung carcinoma is the leading cause of death from cancer. More than 50% of those with small cell lung cancer develop a brain metastasis. Corticosteroid agents, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, median survival for patients with small cell lung carcinoma metastasis is approximately 4 to 5 months after cranial irradiation. In this study the authors examine the efficacy of gamma knife surgery for treating recurrent small cell lung carcinoma metastases to the brain following tumor growth in patients who have previously undergone radiation therapy, and they evaluate factors affecting survival. Methods. A retrospective review of 27 patients (47 recurrent small cell lung cancer brain metastases) undergoing radiosurgery was performed. Clinical and radiographic data obtained during a 14-year treatment period were collected. Multivariate analysis was utilized to determine significant prognostic factors influencing survival. The overall median survival was 18 months after the diagnosis of brain metastases. In multivariate analysis, factors significantly affecting survival included: 1) tumor volume (p = 0.0042); 2) preoperative Karnofsky Performance Scale score (p = 0.0035); and 3) time between initial lung cancer diagnosis and development of brain metastasis (p = 0.0127). Postradiosurgical imaging of the brain metastases revealed that 62% decreased, 19% remained stable, and 19% eventually increased in size. One patient later underwent a craniotomy and tumor resection for a tumor refractory to radiosurgery and radiation therapy. In three patients new brain metastases were demonstrating on follow-up imaging. Conclusions. Stereotactic radiosurgery for recurrent small cell lung carcinoma metastases provided effective local tumor control in the majority of patients. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including radiosurgery can extend survival.

Relief of facial pain after combined removal of precentral and postcentral cortex

1971 ◽  
Vol 34 (4) ◽  
pp. 537-543 ◽  
Author(s):  
Richard A. Lende ◽  
Wolff M. Kirsch ◽  
Ralph Druckman
Keyword(s):  
Facial Pain ◽  
The Other ◽  
Precentral Gyrus ◽  
Nerve Section ◽  
Content Type ◽  
Burning Pain ◽  
Cortical Localization ◽  
The Brain ◽  
Fine Print ◽  
Frontal Lobotomy

✓ Cortical removals which included precentral and postcentral facial representations resulted in relief of facial pain in two patients. Because of known failures following only postcentral (SmI) ablations, these operations were designed to eliminate also the cutaneous afferent projection to the precentral gyrus (MsI) and the second somatic sensory area (SmII). In one case burning pain developed after a stroke involving the brain stem and was not improved by total fifth nerve section; prompt relief followed corticectomy and lasted until death from heart disease 20 months later. In the other case persistent steady pain that developed after fifth rhizotomy for trigeminal neuralgia proved refractory to frontal lobotomy; relief after corticectomy was immediate and has lasted 14 months. Cortical localization was established by stimulation under local anesthesia. Each removal extended up to the border of the arm representation and down to the upper border of the insula. Such a resection necessarily included SmII, and in one case responses presumably from SmII were obtained before removal. The suggestions of Biemond (1956) and Poggio and Mountcastle (1960) that SmII might be concerned with pain sensibility may be pertinent in these cases.

Hyperthermia catheter implantation and therapy in the brain

1990 ◽  
Vol 72 (6) ◽  
pp. 975-979 ◽  
Author(s):  
J. Alexander Marchosky ◽  
Christopher J. Moran ◽  
Neal E. Fearnot ◽  
Charles F. Babbs
Keyword(s):  
Computerized Tomography ◽  
Malignant Gliomas ◽  
Twist Drill ◽  
Ct Scanner ◽  
Tumor Blood Flow ◽  
Content Type ◽  
Catheter Implantation ◽  
Computer Controlled ◽  
Drill Holes ◽  
The Brain

✓ For the treatment of malignant gliomas, a technique for implanting hyperthermia catheters was developed that utilized a stereotactic template and head-stabilization frame mounted on a computerized tomography (CT) scanner. Computerized tomography scans were used to measure tumor dimensions and to determine the number, implantation depths, and active heating lengths of the catheters, which were implanted through twist-drill holes while the patient was in the CT room. Heat was subsequently delivered via implanted catheters using a computer-controlled hyperthermia system, which partially compensates for heterogeneous and time-varying tumor blood flow.

Simulation of multiwavelength conditions in laser picosecond ultrasonics

SIMULATION ◽  
2021 ◽  
pp. 003754972199645
Author(s):  
Philippe Babilotte
Keyword(s):  
Numerical Simulations ◽  
Acoustic Signal ◽  
Acoustic Waves ◽  
Bulk Material ◽  
Deformation Field ◽  
Optical Pump ◽  
Pump And Probe ◽  
Oriented Object ◽  
Numerical Approaches ◽  
Picosecond Ultrasonics

Complete numerical simulations are given under SciLab® and MATLAB® coding environments, concerning propagative acoustic wavefronts, for laser picosecond ultrasonics under multiwavelength conditions. Simulations of the deformation field and its propagation into bulk material are given under different wavelength configurations for optical pump and probe beams, which are used to generate and to detect the acoustic signal. Complete insights concerning the dynamics of the acoustic waves are given, considering the absence of carrier diffusions into the material. Several numerical approaches are proposed concerning both the functions introduced to simulate the wavefront ( Heaviside or error) and the coding approach (linear/vectorized/ Oriented Object Programming), under the pure thermo-elastic approach.

Thymidine kinase-mediated killing of rat brain tumors

1993 ◽  
Vol 79 (5) ◽  
pp. 729-735 ◽  
Author(s):  
David Barba ◽  
Joseph Hardin ◽  
Jasodhara Ray ◽  
Fred H. Gage
Keyword(s):  
Gene Therapy ◽  
Brain Tumors ◽  
Tumor Cells ◽  
Wild Type ◽  
Cns Disorders ◽  
Content Type ◽  
Potential Applications ◽  
Ganciclovir Treatment ◽  
The Brain ◽  
Fine Print

✓ Gene therapy has many potential applications in central nervous system (CNS) disorders, including the selective killing of tumor cells in the brain. A rat brain tumor model was used to test the herpes simplex virus (HSV)-thymidine kinase (TK) gene for its ability to selectively kill C6 and 9L tumor cells in the brain following systemic administration of the nucleoside analog ganciclovir. The HSV-TK gene was introduced in vitro into tumor cells (C6-TK and 9L-TK), then these modified tumor cells were evaluated for their sensitivity to cell killing by ganciclovir. In a dose-response assay, both C6-TK and 9L-TK cells were 100 times more sensitive to killing by ganciclovir (median lethal dose: C6-TK, 0.1 µg ganciclovir/ml; C6, 5.0 µg ganciclovir/ml) than unmodified wild-type tumor cells or cultured fibroblasts. In vivo studies confirmed the ability of intraperitoneal ganciclovir administration to kill established brain tumors in rats as quantified by both stereological assessment of brain tumor volumes and studies of animal survival over 90 days. Rats with brain tumors established by intracerebral injection of wild-type or HSV-TK modified tumor cells or by a combination of wild-type and HSV-TK-modified cells were studied with and without ganciclovir treatments. Stereological methods determined that ganciclovir treatment eliminated tumors composed of HSV-TK-modified cells while control tumors grew as expected (p < 0.001). In survival studies, all 10 rats with 9L-TK tumors treated with ganciclovir survived 90 days while all untreated rats died within 25 days. Curiously, tumors composed of combinations of 9L and 9L-TK cells could be eliminated by ganciclovir treatments even when only one-half of the tumor cells carried the HSV-TK gene. While not completely understood, this additional tumor cell killing appears to be both tumor selective and local in nature. It is concluded that HSV-TK gene therapy with ganciclovir treatment does selectively kill tumor cells in the brain and has many potential applications in CNS disorders, including the treatment of cancer.

Experimental delayed radiation necrosis of the brain

1979 ◽  
Vol 51 (5) ◽  
pp. 587-596 ◽  
Author(s):  
Albert N. Martins ◽  
Ralph E. Severance ◽  
James M. Henry ◽  
Thomas F. Doyle
Keyword(s):  
Rhesus Monkeys ◽  
Radiation Necrosis ◽  
Clinical Signs ◽  
Control Group ◽  
Content Type ◽  
Brain Irradiation ◽  
Primate Brain ◽  
High Doses ◽  
The Brain ◽  
Male Rhesus

✓ The authors have designed an experiment to detect a hitherto unrecognized interaction between high doses of the glucocorticoid, dexamethasone, and brain irradiation. Eighteen juvenile male rhesus monkeys received 1800 rads to the whole brain in 8.5 minutes. For 1½ days before and 10½ days after the irradiation, nine animals received approximately 2.9 mg/kg/day of dexamethasone intramuscularly in addition to irradiation, while the remaining nine animals served as the control group and received saline. All animals eventually developed a progressive neurological syndrome, and died of delayed radiation necrosis of the brain. The two groups were compared with regard to latency to onset of clinical signs, survival time, and number, distribution, and location of lesions of radionecrosis. Large doses of dexamethasone did not alter the susceptibility of the primate brain to delayed radiation necrosis. Detailed morphological study of the radionecrotic lesions supports the hypothesis that most, if not all, of the lesions develop as the consequence of injury to blood vessels.

Arteriovenous malformations in the posterior fossa

1977 ◽  
Vol 47 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Hiroshi Matsumura ◽  
Yasumasa Makita ◽  
Kuniyuki Someda ◽  
Akinori Kondo
Keyword(s):  
Arteriovenous Malformation ◽  
Brain Stem ◽  
Posterior Fossa ◽  
Arteriovenous Malformations ◽  
Cerebellopontine Angle ◽  
Anterior Part ◽  
Content Type ◽  
The Brain ◽  
Fine Print

✓ We have operated on 12 of 14 cases of arteriovenous malformation (AVM) in the posterior fossa since 1968, with one death. The lesions were in the cerebellum in 10 cases (three anteromedial, one central, three lateral, and three posteromedial), and in the cerebellopontine angle in two; in two cases the lesions were directly related to the brain stem. The AVM's in the anterior part of the cerebellum were operated on through a transtentorial occipital approach.

Craniocerebral missile injuries in the monkey: an experimental physiological model

1972 ◽  
Vol 36 (1) ◽  
pp. 43-49 ◽  
Author(s):  
Arthur M. Gerber ◽  
Robert A. Moody
Keyword(s):  
Rhesus Monkeys ◽  
Common Factor ◽  
Blood Gases ◽  
Physiological Model ◽  
Content Type ◽  
Epidural Compression ◽  
The Brain ◽  
Strong Suspicion ◽  
Fine Print ◽  
Carotid Flow

✓ Experiments were carried out on rhesus monkeys to determine what physiological parameters were most closely correlated with death due to craniocerebral missile injuries. Observations of intracranial pressure, blood pressure, carotid flow, blood gases, respiratory rate, depth and volume, and electroencephalograms were made. These parameters were compared in survivors and nonsurvivors as were the pathological injuries. The most important single parameter that correlated with death was the drop in carotid flow. As this same correlation has been observed in epidural compression experiments in the monkey, there is a strong suspicion that reduced blood flow to the brain as measured by carotid flow is a common factor in craniocerebral missile injuries and epidural compression injuries.

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