Experimental study of high-resolution ultrasound imaging of hemorrhage, bone fragments, and foreign bodies in head trauma

Cerebral ventricular size in developing normal kittens measured by ultrasonography

To evaluate the age of fontanelle closure of normal kittens and the size of their lateral ventricles, 50 ultrasonographic examinations using the bregmatic fontanelle as an acoustic window were made. Seven kittens, laboratory animals, were included in the study. To verify the location of the lateral ventricle, two of the kittens were sacrificed as neonates. In one of them ink was injected prior to autopsy into one lateral ventricle under sonographic guidance. In a longitudinal study of five of the kittens, the skull depth and the depth of the central part of the lateral ventricle reproduced in a longitudinal view could be measured up to the age of about 5 months. During that period, the skull depth increased from a median value of 1.95 cm (1.92-1.98) in a seven-day-old cat to 2.58 cm (2.52-2.59) in a 154-day-old cat, while the afore-mentioned ventricle values increased from 0.3 mm to 1.1 mm.

The use of ultrasonography for the detection of retained wooden foreign bodies in the foot

The efficacy of ultrasonography for the detection of wooden foreign bodies in the foot was analyzed retrospectively. Twenty patients underwent real-time, high-resolution ultrasound studies (7.5 or 10 MHz, linear array transducers) to rule out the presence of a wooden foreign body in their feet. Ten out of the 20 patients had positive ultrasound findings for a wooden foreign body. With the aid of the ultrasound study and preoperative markings, the subsequent mean surgical time was 20.8 minutes, with a 100% retrieval rate of the foreign body. Ultrasound was found to be 100% sensitive in the detection of wooden foreign bodies in the soft tissues of the foot. Ultrasonography should be considered an important diagnostic modality in the foot and ankle surgeon's armamentarium for the detection of retained wooden foreign bodies.

The value of intraoperative ultrasound in neurosurgery

Intraoperative ultrasound is not a technique which has been widely accepted by neurosurgeons in this country, not least because bulky probes and machines become more of a hindrance than an asset in theatre. The development of new smaller probes, including ones small enough to visualize the brain through a conventional burr-hole has rekindled interest in this subject. Its use for guidance in tumour biopsy, cyst aspiration and catheter placement, as well as volume estimations and determining the completeness of tumour resection, are outlined. The ability to recognize peri-operative haemorrhage is demonstrated.

Intraoperative ultrasound (US) imaging. Comparison of pathomorphological findings in US and CT

Experience with the use of intraoperative ultrasound (US) imaging in over 300 patients are presented in this paper and discussed with special reference to various pathomorphologies as well as their identifiability within the brain/intracranium. In 201 of these patients, the pathomorphological peculiarities in US could be compared with preoperative CT findings. As a general result, all investigated lesions could be identified during intraoperative US investigations with the exception of small aneurysms. Most of the lesions gave at least partly higher echosignals than normal brain tissue, except arachnoid cysts. Size and shape of lesions were comparable in US and CT with the exception of some gliomas; in the latter group, the diffuse image in US was more akin to the situation likely to be found by the surgeon during operation, whereas CT used to give a misleading picture of a more or less clearly delineated tumour. US allowed more accurate differentiation between intratumoural necrosis and cysts than CT: the latter was misleading in many instances. At the present state of development, real time US imaging does not allow a histopathological diagnosis. The ease of handling and the high quality of morphological imaging, however, warrant a number of practical applications in daily neurosurgical practice.

Practical application of intraoperative ultrasound imaging

Intraoperative real-time ultrasound imaging (US) was used in over 500 patients to investigate which of the previously considered applications are of practical use in everyday neurosurgery. During all intraoperative applications for a wide variety of pathological conditions, small deep-seated as well as subcortically located lesions were detected with accuracy; in many instances they could be approached through smaller surgical exposures. US guidance was accurate in 209 cases for the stereotactic introduction of needles or endoscopes into various lesions: thus burrhole evacuation was performed on 148 intracerebral haematomas; in 16 patients endoscopic biopsy and resection of ventricular tumours was performed as well as biopsies of 39 hemispheric brain tumours and aspiration of a brain abscess in 6 instances. Seventy six gliomas were investigated by US imaging; the frequently unclear boundary between tumour and surrounding oedema was not better visualized than with CT or MRI. Moreover, US imaging for the detection of residual tumour towards the end of operation was unreliable. Postoperative imaging through burrholes or other cranial defects was mostly of unacceptably low quality for therapeutic decision making.

Correlation of neuropathologic findings, computerized tomographic and high-resolution ultrasound scans of canine avian sarcoma virus-induced brain tumors

The location, size, geometry and neuropathological findings of anaplastic astrocytomas (AA), gliosarcomas and sarcomas induced by the avian sarcoma virus (ASV) in dogs were compared with images generated using computerized tomography (CT) and real time high-resolution ultrasound (HRUS). Seven AA showed a wide range of findings on CT. Pre-contrast CT scans showed that the tumors could be hyper, hypo, or isodense. Three of seven AA had no contrast enhancement; two of these tumors were also isodense which resulted in a false-negative CT exam. Partial enhancement was seen in one tumor. This resulted in a sensitivity of detection of 72%. Real time HRUS was able to define tumor location, size and geometry of the AA missed or incompletely imaged by CT. All tumors were hyperechoic. Inhomogeneity of the echo pattern was due to hemorrhage, cyst formation, and necrosis within the tumors. Such secondary tumor characteristics were more accurately defined by HRUS compared to CT. Vasogenic edema in the brain surrounding tumors was of low density on CT and hypoechoic or indistinguishable from normal brain on US. Similar findings were seen in six gliosarcomas, two of which were not visualized by either pre- or post-contrast enhanced CT scans (sensitivity of 66%). Sarcomas differed in that they were either hyper or isodense; none were hypodense. The area of increased density matched the tumor geometry and correlated with dense cellularity and reticulin deposition. All 13 sarcomas showed contrast enhancement (100% sensitivity), but in two tumors, contrast enhanced CT underestimated the size of the tumor. Because of the large size and multiplicity of the sarcomas, HRUS imaging was not able to resolve the entire tumor volume because of limited imaging access. Intravenously injected horseradish peroxidase (HRP) crossed the tumor blood-brain barrier (BBB) only in those tumors in which contrast enhancement was seen. These studies suggest that intraoperative HRUS imaging may be useful in detecting and delineating human AA incompletely visualized by CT.

Ultrasound examination of foreign bodies. An in vitro investigation

Ultrasound examination of foreign bodies most frequently encountered in the human body was performed when they were contained within a transmission medium acoustically resembling human soft tissues. All the foreign bodies evaluated (lead and plastic pellets, pieces of wire, nails, needles, small fragments of rock and glass, wooden slivers, surgical sponges and surgical threads) were detectable with ultrasound. Strong echoes were reflected from their surface when they were positioned favourably, although in some positions the echoes from a needle, fragment of glass, wooden silver, or surgical thread could not be distinguished from those of the surroundings. Acoustic shadows were also seen behind the foreign bodies. A striking column of reverberation echoes was demonstrated behind lead pellets and nails while behind a glass plate there was an acoustic shadow that was often difficult to detect because it was concealed by a mirror image. With modern grey-scale real-time equipment it is possible to demonstrate objects from various angles, a fact which should facilitate the detection of foreign bodies in vivo circumstances.

Xeroradiography and ultrasonography in the evaluation of a penile injury

A 34-year-old white man presented with severe penile cellulitis following injection of epoxy glue into the shaft of the penis. Preoperative xeroradiography and ultrasonography localized the hardened masses of glue to the left corpus cavernosum and subcutaneous tissues. Under the guidance of intraoperative ultrasonography this foreign material was removed surgically. Postoperatively, the cellulitis resolved promptly and xeroradiography demonstrated no residual fragments. Although various modalities, including computerized tomography and roentgenography, are available to detect foreign bodies in soft tissues, xeroradiography and ultrasonography are ideally suited for use in the male external genitalia.

Intraoperative localization of intracranial lesions with real time ultrasound

High resolution ultrasound has been used intraoperatively on forty-five patients with various intracranial lesions. The technique is quickly and easily carried out under sterile conditions in the operating room. Successful localization of both primary and metastatic tumors of various sizes, depths and consistencies have been made prior to extirpation or biopsy. Several of the biopsies were done through small burr holes. Arteriovenous malformations, abscesses, bone fragments from trauma, gliotic epileptic foci and ventricles for shunt placement have been readily found. No significant complications have been encountered. A new technique for localizing superficial lesions is described. An overall reduction in operating time and unnecessary trauma to the patient has resulted from more accurate intraoperative localization of intracranial lesions with real time ultrasound.

Intraoperative Doppler and real time sonography in neurosurgery

Ultrasound Doppler sonography with miniaturized probes and high resolution offers new possibilities of intraoperative control of neurovascular procedures. Patency, flow direction stenoses and changes in resistance can be investigated atraumatically, repeatedly and without additional preparation. In bypass and aneurysm surgery, about 10% of the cases were shown by Doppler examinations to be unsatisfactory, with stenoses and occlusions. These could be immediately corrected without loss of time. In normal cases, the information on the local haemodynamics enlarges the knowledge as to the effects of the operation and make it safer. Real time ultrasonography, which can be easily adapted to neurosurgery, is a new atraumatic tool for localizing, in two dimensions, subcortical intrinsic processes, haematomas, ventricles ect. It is useful for guided biopsies and punctures and for the centering of the dura and brain incision over the middle of the lesion, especially in microsurgical procedures.

Cottonoid as an acoustical marker for intraoperative ultrasound scanning. Technical note

The authors demonstrate the use of cottonoid as a marker for ultrasound localization of a subcortical tumor.

Preliminary experiences with "real-time" intraoperative ultrasonography associated to the laser and the ultrasonic aspirator in neurosurgery

Twelve cerebral lesions were operated upon with various laser sources (carbon dioxide, neodymium-yttrium-argon-garnet, and argon) and with an ultrasonic aspirator utilizing the intraoperative "real-time" ultrasonography. With the last method, the tumor was imaged just as well through the intact dura mater as on the brain surface itself, allowing a precise localization of deep intracranial lesions. A sharp selectivity on the healthy tissues is, in this way, achievable to reach the tumor, which is successively removed with the laser and ultrasonic aspirator checking the surgical maneuvers on the visual control of the ultrasonograph.

Ultrasound-guided biopsy for deep-seated brain tumors

✓ An easy, accurate, and safe biopsy technique for deep-seated brain tumors using a newly devised real-time ultrasonic apparatus is presented. Three lesions, one large pituitary adenoma and two pineal region tumors, were biopsied successfully by this technique.

Intraoperative use of real-time ultrasonography in neurosurgery

The authors' experience with the intraoperative use of real-time ultrasonography during 21 neurosurgical procedures is reported. These procedures include neoplasm surgery in 18 cases, treatment of an arteriovenous malformation in one case, and ventricular catheter placement for hydrocephalus in two cases. In each of the neoplasm cases, the tumors were imaged just as well through the intact dura as on the brain surface itself. There were no cases in which the pathology could not easily be identified. The use of portable intraoperative ultrasonography in sterile coverings has proven to be extremely useful in localizing small subcortical neoplasms, as well as locating the solid and cystic portions of deep lesions. It has assisted in guiding needles for both biopsy and aspiration. It has also accurately identified and guided Silastic catheters during their placement in the ventricular system in cases of hydrocephalus. The authors have found real-time ultrasonography to be an important new tool in the operating room and will continue to rely on its imaging ability during selected procedures in the future.