The outcome of treatment for malignant brain tumors is still disappointing. For this reason, total removal of the tumor is required to obtain a better outcome. It is acknowledged that en bloc total removal of a tumor by lobectomy results in a better outcome than subtotal or partial removal. For extensive removal of a tumor, recognition of the location, infiltration, and cleavage of the tumor is very important. We tried to carry out intraoperative ultrasonography in order to obtain data about brain tumors. We examined three cases of glioblastoma in the frontal region, two in the temporal region, and one in the occipital region, and a case of recurrent malignant meningioma in the temporal region. Extra- and intradural intraoperative ultrasonography was carried out, and silastic or plastic tubes were implanted around the tumor under ultrasonographic guidance. Thus en bloc total removal of the tumor was carried out successfuly without any neurological deficit. The application of intraoperative ultrasonography for malignant brain tumors is very useful, and should help to improve postoperative outcome.
We describe our experience with the clinical application of intraoperative spinal ultrasonography (IOSU) and discuss its utility and limitations. Materials: A Sonolayer SSA-260A (Toshiba Medical Co., Ltd.) ultrasound unit, with 7-MHz and 5-MHz sector transducers, was used to evaluate 40 patients, beginning in April 1994. Diagnose included 12 cases of spondylosis, 10 of tumor, 9 of syringomyelia, 5 of vascular malformation and 4 of miscellaneous diseases. After exposing the dura, the operative field was immersed in sterile saline. Real time scanning was performed by the stand-off method. Results: In cases where an anterior approach was used for treatment of spondylosis and ossification of the posterior longitudinal ligament, IOSU was valuable for determining the degree of lateral corpectomy. Also spinal cord vascular pulsation could be confirmed to assess the completeness of decompression. In case where a posterior approach was utilized for lesion resection, IOSU was particularly useful for lesion localization. This allowed the dural incision to be tailored to a particular lesion, and for evaluating the completeness of resection. Lesions were confidently identified in all cases prior to resection. However, sonographic visualization of the surgical bed following resection of the lesion was suboptimal. Obscuration of the surgical site was caused by air bubbles, hemorrhage, obstruction of the sonographic window by hemostats or other instruments, or by synthetic dural patches. Conclusions : IOSU is a non-invasive and reproducible technique that is valuable for real-time intraoperative planning and monitoring of spinal surgical procedures. The technique does not significantly increase operation time. Limitations include the requirement of an unobstructed sonographic window, and the value of the technique is highly dependent on operator experience in image acquisition and interpretation. Routine use of this technique would offer the benefits described above, and would soon overcome the major limitations resulting from lack of user familiarity with its performance.
We attempted to evaluate intracranial cerebral vessels in neonates using a newly developed power flow Doppler imaging method. Four normal- term neonates were examined through the anterior fontanel. The artery system, including the anterior cerebral, middle cerebral, posterior cerebral, basilar and lenticulostriate arteries, was well visualized in all subjects. The venous system, including the internal cerebral vein, Galen vein, and straight and transverse sinuses, was also clearly demonstrated in all cases. Power flow methods clearly revealed slow- flow vessels and small vessels, which could not be demonstrated by conventional color Doppler methods. The middle cerebral artery, which crossed the ultrasound beam vertically, was visualized by the power flow method. We also examined the blood flow velocities at three points of the lenticulostriate artery (LSA) by pulsed Doppler under guiding power flow imaging. The maximum and minimum flow velocities decreased gradually from the central to the peripheral portion. The resistance indices and pulsatility indices at each position were not significantly different. These findings suggest that measurement of the LSA can be used to evaluate the peripheral circulation in a focal region of the brain.
TCD findings used for evaluating vasospasm (VSP) due to ruptured aneurysm are controversial. To clarify these TCD findings, intra-arterial DSA (IA-DSA) was applied to study morphological changes and to measure cerebral circulation time (CCT) . Forty-six patients with ruptured aneurysms treated by neck clipping at the acute stage were investigated. Clinical grade and CT findings were estimated using the Hunt and Hess classification and Fisher's classification, respectively. Mean flow velocity (MFV) in the M1 segment was measured by TCD. IA-DSA was performed on the day 7-13 day. Angiographic VSP was categorized by Fisher's classification. CCT was defined by the time difference between the two peak optical density curves recorded by IA-DSA at the carotid artery (C3-4) and the ascending vein. Mean CCT was 3.7 sec in patients without VSP and 4.3 sec in those with slight to moderate VSP, which were significantly different from mean CCT, 6.2 sec, in patients with severe VSP. MFV in patients with no, slight to moderate, and severe VSP was 82, 104 and 124 cm/sec, respectively, none of the differences being significant. Additionally, patients with diffuse VSP extending from the M2 to peripheral sites showed increased CCT values and an unchanged MFV value. These findings suggest that use of the MFV at the M1 segement for estimating the severity of diffuse peripheral VSP is problematic.
Transcranial Doppler ultrasonography (TCD) has been widely used for assessment of cerebrovascular diseases. We studied the correlation of single photon emission computed tomography (SPECT) and TCD during pre- and post-superficial temporal artery (STA) -middle cerebral artery (MCA) bypass surgery. The patients were seven males (mean age : 63 (57-70) yrs) with occlusion of the internal carotid artery (ICA) undergoing STA-MCA bypass surgery. Two of the patients had bilateral occlusion of the ICA. Mean flow velocity (MFV) and pulsatility index (PI) of the MCA and STA were measured using a TC2-64 and a Transscan. Cerebrovascular reserve capacity was studied using SPECT with Diamox challenge. After bypass surgery, STA-MFV increased and STA-PI decreased on TCD in all subjects. In five of them, STA-MFV increased to more than 30 cm/sec. SPECT studies showed improvement of the cerebrovascular reserve capacity in all patients. Thus, TCD study of STA is useful for evaluating the effect of EC-IC bypass surgery in patients with occlusion of the ICA.
Recently, technology for showing information on flow within the body by ultrasound has advanced rapidly, and very fine, low flow can now be detected. However, in some cases, misreading of Doppler information can occur due to lack of basic knowledge about Doppler. This article gives basic information about Doppler for practical routine diagnostics.