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.

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従来より, 頚動脈狭窄性病変の診断のgold standardは血管造影法であったが, 合併症を惹起する可能性のある侵襲的検査であり, 精度の高い非侵襲的評価方法の開発が望まれてきた.頚部超音波パワードプラ法 (PDI) は, 血管内腔の形態を評価する為, 近年開発された新しい超音波診断法である.パワードプラ法の実用原理の臨床応用により, 動脈血管狭窄部位の連続血流の可視化の感度は向上している.本論文では, 内頚動脈狭窄症評価における, パワードプラ法の診断上の意義と, カラードプラ法 (CDFI) 及び血管造影法との比較調査を行なった.
著者らは, 128の内頚動脈狭窄血管と12の内頚動脈閉塞性病変をパワードプラ法, カラードプラ法, 血管造影法により連続評価した (全例が50%以上狭窄) .内腔の狭窄率は, PDI法, CDFI法ともに縦断像及び横断像により, それぞれ内腔口径および面積の狭窄度をを計算することによって測定した.血管造影上の狭窄度は, 従来の報告よりNASCET, ECST, CC methodsの方式を利用し計測された.
結果として, PDI法は狭窄血管内腔を, 特に石灰化を伴うような複雑な高度狭窄病変において, CDFI法より有意に明瞭に描出した (92%vs79%, P<0.01) .直線回帰分析では, 口径狭窄率, 面積狭窄率ともにPDI法とCDFI法とで密接な相関を示した.内頚動脈狭窄度分類では, 80～90%の面積狭窄例において, 両者間で最良の一致を示した.血管造影法では, PDI法とCDFI法の両方との比較において, NASCET方式では内腔狭窄率の過少評価, ECST, CC methods方式では過大評価がみられた為, 超音波法と血管造影法との相関は中等度に留まった (p<.001) .
PDI法ではCDFI法に比較して狭窄血管内腔の可視化能力が向上し, 内頚動脈狭窄の評価を改善した.血管造影法により測定する狭窄度は, 各研究の評価方式に依存しているが, PDI法, CDFI法の両者による狭窄部プラークの超音波イメージングは局所の狭窄度の直接的評価を可能にするといえよう.

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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.

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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.

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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 (C_3-4) 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.

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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.

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経頭蓋超音波法 (TCD) において特徴的な音を伴って検出されるhigh intesity signalは, これまでの動物実験や臨床研究により気泡性か固形成分の微小塞栓子であることが確認されている.検出される微小塞栓子の大部分は無症候性であるが, 塞栓源の活動性や部位の同定の助けとなり, またその検出例での塞栓症発症頻度の増加に関する知見も得られている.本検出法を発展させていく意義は, 塞栓症に対する予防的治療を行うべき患者の選別に利用できるかと言う点にあるといえよう.本検出法が今後解決すべき問題点として, 微小塞栓子の性状鑑別がある.これまでに心臓機械弁置換患者において検出される微小塞栓子は大部分気泡成分であるとする報告がある.著者らも, 機械弁置換患者に酸素を吸入させるとembolic signal (以下ES) 数が顕著に減少し, 同患者におけるESがほとんど気泡性であることを報告してきた.本論文では対象を広げ, 血管原性塞栓症患者の塞栓子が非気泡成分であることを証明することを目的としている.
機械弁患者20例, 塞栓源となる血管病変を持っ患者78例, コントロール20例に対して, 室内空気下で30分間, 酸素吸入 (6L/min) フェイスマスク下で30分間, 中大脳動脈または後大脳動脈をTCDによりモニターし, ESを検出した.機械弁患者では酸素非吸入下に比し吸入下で有意にESが減少したが (144 versus 63; P=.002) , 有血管塞栓源患者では, 有意な減少を認めなかった (145 versus 135; NS) .コントロール群ではESを検出しなかった.
機械弁患者においては機械弁周囲に気泡形成 (cavitation) を認めることが明らかにされているが, 酸素吸入により血中の酸素分圧が上昇すると, 気泡形成が抑制されるとともに, 形成された気泡もすばやく再溶解し, 循環血液内への気泡の流入も減少する.機械弁患者のESは酸素吸入時に減少することにより, 大部分気泡成分であると言える.一方, 血管に塞栓源を有する患者においては, 酸素吸入でESが減少せず, 同患者でのESが気泡性ではなく, 血栓や粥腫由来の固形成微小栓子であることが証明された.
酸素吸入という単純な操作が, TCDにより検出される微小塞栓子の性状解析の一助になることが明らかにされた.

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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.

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