title: Real-time 3-d intracranial ultrasound with an endoscopic matrix array transducer.
abstract: A transducer originally designed for transesophageal echocardiography (TEE) was adapted for real-time volumetric endoscopic imaging of the brain. The transducer consists of a 36 x 36 array with an interelement spacing of 0.18 mm. There are 504 transmitting and 252 receive channels placed in a regular pattern in the array. The operating frequency is 4.5 MHz with a -6 dB bandwidth of 30%. The transducer is fabricated on a 10-layer flexible circuit from Microconnex (Snoqualmie, WA, USA). The purpose of this study is to evaluate the clinical feasibility of real-time 3-D intracranial ultrasound with this device. The Volumetrics Medical Imaging (Durham, NC, USA) 3-D scanner was used to obtain images in a canine model. A transcalvarial acoustic window was created under general anesthesia in the animal laboratory by placing a 10-mm burr hole in the high parietal calvarium of a 50-kg canine subject. The burr-hole was placed in a left parasagittal location to avoid the sagittal sinus, and the transducer was placed against the intact dura mater for ultrasound imaging. Images of the lateral ventricles were produced, including real-time 3-D guidance of a needle puncture of one ventricle. In a second canine subject, contrast-enhanced 3-D Doppler color flow images were made of the cerebral vessels including the complete Circle of Willis. Clinical applications may include real-time 3-D guidance of cerebrospinal fluid extraction from the lateral ventricles and bedside evaluation of critically ill patients where computed tomography and magnetic resonance imaging techniques are unavailable.
authors.affiliation: Department of Biomedical Engineering, Duke University, Durham, NC, USA. edl@duke.edu
authors.forename: Edward D
authors.initials: ED
authors.lastname: Light
authors.forename: Srinivasan
authors.initials: S
authors.lastname: Mukundan
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Wolf
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Smith
mesh_terms: D000818:Animals; D020771:Anterior Cerebral Artery / Q000473:pathology; D001921:Brain / Q000473:pathology; D002343:Carotid Artery, Internal / Q000473:pathology; D003287:Contrast Media; D004285:Dogs; D004453:Echoencephalography / Q000295:instrumentation / Q000379:methods*; D004867:Equipment Design; D021621:Imaging, Three-Dimensional / Q000295:instrumentation / Q000379:methods; D007430:Intraoperative Care / Q000379:methods; D018810:Magnetic Resonance Angiography / Q000379:methods; D019047:Phantoms, Imaging; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D003287:Contrast Media