早川 基治

The role of three-dimensional computed tomography angiography (3D-CTA) in management of aneurysms has been fairly acknowledged in the past. There have been numerous articles in the literature regarding its potential threat to the conventional "gold standard", i.e. digital subtraction angiography (DSA). We study the technology used at a tertiary care hospital in Japan which performs a large number of aneurysm surgeries a year and review the recent literature to gain an insight into the current role of 3D-CTA in detection of aneurysms and if it can be a front line modality of investigation from a neurosurgeon's point of view. At many centres including those in India, DSA is still treated as the first choice of investigation. Although 3D CTA has some limitations, it can provide an unmatched multi-directional view of the aneurysmal morphology and its surroundings including relations with the skull base and blood vessels. This may provide an invaluable help to a neurosurgeon who is usually concerned about many other associated factors involved in approaching an aneurysm.

Sub-arachnoid hemorrhage (SAH) has been easily one of the most debilitating neurosurgical entities as far as stroke related case mortality and morbidity rates are concerned. To date, it has case fatality rates ranging from 32-67%. Advances in the diagnostic accuracy of the available imaging methods have contributed significantly in reducing morbidity associated with this deadly disease. We currently have computed tomography angiography (CTA), magnetic resonance angiography (MRA) and the digital subtraction angiography (DSA) including three dimensional DSA as the mainstay diagnostic techniques. The non-invasive angiography in the form of CTA and MRA has evolved in the last decade as rapid, easily available, and economical means of diagnosing the cause of SAH. The role of three dimensional computed tomography angiography (3D-CTA) in management of aneurysms has been fairly acknowledged in the past. There have been numerous articles in the literature regarding its potential threat to the conventional "gold standard" DSA. The most recent addition has been the introduction of the fourth dimension to the established 3D-CT angiography (4D-CTA). At many centers, DSA is still treated as the first choice of investigation. Although, CT angiography still has some limitations, it can provide an unmatched multi-directional view of the aneurysmal morphology and its surroundings including relations with the skull base and blood vessels. We study the recent advances in the diagnostic approaches to SAH with special emphasis on 3D-CTA and 4D-CTA as the upcoming technologies.

This study compared digital measurement of aneurysm volume by 3D rotational angiography (3D-RA) with an approximation technique using three diameters of an aneurysm to re-interpret previously reported optimal packing densities (volume embolization ratio, VER) in coil embolization of intracranial aneurysms. Estimation of the volume of saccular aneurysms is important for calculation of the V ER, which is in turn reported to be useful for prediction of coil compaction. The conventional formula for the volume estimation is V=4/3 pi(A/2) (B/2) (C/2), where A, B, and C are the aneurysmal height, length, and width measured on 3D-RA image respectively. Using 3D rotational angiography data from 74 aneurysms, the approximated volume generated using the conventional formula was directly compared with the digitally measured volume. The digitally measured volume varied from 0.003 ml to 7.935 ml, and the dome-to-neck ratio (D/N) from 0.79 up to 4.62. We found that the conventional formula almost systematically underestimated the volume by up to 50 %, particularly when the neck was large relative to the dome (D/N<2). On average, digitally measured volume was 1.26 similar to 1.29 times larger than the approximated volume obtained using the conventional formula. Conventional 2D angiography based aneurysm volume calculation tends to underestimate an aneurysm volume, so the so-called VER (volume embolization ratio) could be overestimated.

Area Detector CT(AD-CT)は単に検出器が増えただけでなく,頭部を1回転で撮影できるほどに広くなった.通常の3D-CTAでは1秒程度で撮影が終了するため,造影剤の減量が可能となる.また,シーケンシャルスキャンにより動脈相〜静脈相までのvolume dataを連続的に取得できる.連続ボリュームスキャンでは心電同期下で撮影を行うことにより,頭部から,頚動脈,心臓(冠動脈)まで一度に検査が可能である.また160列ヘリカルスキャンも可能となり,頭部から恥骨部まで6秒程度で撮影が可能である.AD-CTではさまざまな検査ができるため,検査目的に適した撮影方法の選択,適切な照射線量,適切な再構成や解析も重要である.

35歳(2経妊1経産)。患者は妊娠29週1日に意識障害を認め、母体搬送された。所見ではJCSII-10で、CTでは延髄左側くも膜下腔に高吸収域が認められた。そして、3D-CT angioより左前下小脳動脈の解離性動脈瘤破裂によるくも膜下出血(SAH)と診断され、29週3日目に血管内手術による脳動脈瘤塞栓術が行われ、妊娠は継続した。術後、意識レベルは徐々に改善したが、頭痛と左下肢麻痺がみられ、MRIによる検査を行ったところ、T1強調で右前頭葉皮質静脈のflow void消失、拡散強調で右前頭葉大脳皮質部の高信号域が認められ、あわせてMR venographyでは直静脈洞の陰影欠損と上矢状静脈洞の血流低下が確認された。以上より、本症例はSAHに合併した脳静脈洞血栓症と診断され、31週1日目に低分子ヘパリンの投与を開始した。その結果、頭痛や左下肢麻痺の回復、画像所見の改善を認め、以後、38週6日目にオキシトシンによる分娩誘発を行い、経腟分娩にて3105gの男児が出産した(Apgar score9点/10点)。尚、母子はともに産褥20日目に退院となった。

【目的】近赤外線スペクトロスコピー（NIRS）による術中モニタリング下で急性期にcarotid artery stenting（CAS）を施行した頚部頚動脈狭窄症による脳梗塞の１例を報告する．【症例】右片麻痺および失語にて発症した76歳男性．頭部CTでは明らかな虚血性変化を認めなかったが，CT潅流画像では左中大脳動脈領域に広範囲にpenumbra領域を認めた．3D-CTAでは左内頚動脈起始部に高度狭窄を認めた．治療前はNIRSにて局所酸素飽和度の著明な左右差を認めた．前拡張後，ステントを留置した．ステント留置直後に左側の局所酸素飽和度が10%上昇したため，後拡張は施行せず手技を終了した．術後経過は順調であった．【結論】急性期CASではNIRSの所見が術中の拡張手技のdecision makingに有用である．

Purpose: We report two cases of acute ischemic stroke patients treated by additional thrombectomy using a basket-shaped microsnare (Soutenir) after infusion of intravenous recombinant tissue plasminogen activator (rtPA). Successful recanalization and good prognosis were achieved in both cases.Case 1: A 67-year-old man presented with left hemiplegia and agnosia. After completion of the intravenous rtPA infusion, he continued to show severe neurological deficit. Angiography revealed occlusion of the posterior trunk and a branch of the anterior trunk of the right middle cerebral artery (MCA). The two occluded arteries were successfully recanalized by removing the clot with Soutenir, resulting in neurological improvement.Case 2: A 49-year-old man presented with right hemiplegia and aphasia. After completion of the intravenous rtPA infusion, he continued to show severe neurological deficit. Angiography revealed occlusion of the left MCA at the proximal M1 segment. The occluded artery was successfully recanalized by removing the clot in the manner described above, resulting in neurological improvement.Conclusion: To our knowledge, this is the first report describing patients treated by additional thrombectomy using a Soutenir after failed intravenous infusion of rtPA. This procedure is a therapeutic option for selected acute ischemic stroke patients who are unresponsive to intravenous rtPA.

Background: Our objective was to set up a management-oriented classification for paraclinoid aneurysms, and then design and apply a simplified management scheme according to each group defined by this classification. Methods: Paraclinoid aneurysms were classified as group I (supraophthalmic artery), group II (ophthalmic artery) and group III (infraophthalmic artery) aneurysms intradurally. Between January 2005 and December 2006, 86 cases with 89 paraclinoid aneurysms were treated. There were 35 (40.2%) aneurysms in group I (20 in group Ia, 15 in group Ib), 32 (36.8%) in group II and 20 (23%) in group III. Results: In group I aneurysms, 20 (57.1%) were treated by clipping or/and wrapping, while 15 (42.9%) were managed by coiling. In group II aneurysms, 20 (62.5%) were treated by clipping and 12 (37.5%) by coiling. The contralateral approach was performed for 4 (6%) aneurysms in groups I and II. All 20 group III aneurysms were treated by coiling. The overall rate of permanent complications was 4.6%. The rate of complete occlusion was 92.5% in surgical cases and 55.6% in endovascular ones. The overall outcomes in the treatment of paraclinoid aneurysms were excellent (GOS = 5, 95.4%). Conclusion: Based on our modified classification of paraclinoid aneurysms, a simplified management scheme was designed and applied. For group I (supraophthalmic artery) and group II (ophthalmic artery) aneurysms, surgical clipping or/and wrapping should be the first choice of treatment, while for group III (infraophthalmic artery) aneurysms, endovascular coiling should be the best modality. Additionally, individualizing the treatment planning might contribute to better results. Copyright (C) 2008 S. Karger AG, Basel.

マルチスライスCTは急速に普及し、現在64列の検出器を装備したものが最新モデルとしてリリースされている。マルチスライスCTの多列化が進むにつれ、検査時間の短縮、撮影範囲の拡大、体軸方向の分解能の向上が得られている。64列マルチスライスCTでは、常に0.5mmの薄いスライス厚で撮影することができるため、高い空間分解能のボリュームデータを得ることができる。また、高速三次元再構成ワークステーションの普及により、もはや三次元画像は特別なものではなくなった。64列マルチスライスCTでは、単に高速撮影ができるだけでなく、体軸方向への長距離撮影[頭部から胸部への3D-CT angiography(3D-CTA)]、CT perfusion(CTP)との複合検査、digital subtraction 3D-CT angiography(DS 3D-CTA)、動脈優位相・静脈優位相の多時相撮影など、撮影方法や造影方法を組み合わせることによりさまざまな検査が可能となり、従来よりも検査の幅が広がってきている。本稿では、われわれの施設で行っている64列マルチスライスCT「Aquilion 64」(東芝社製)を用いた神経放射線領域における検査について、実際の症例を提示しながら解説していく。(著者抄録)

Background: A limited series of patients with aneurysm were reviewed retrospectively to analyze strategies for integrating microsurgical and endovascular techniques in the management of complex, surgically intractable aneurysms. Methods: Four patients were managed in Fujita Health University with a multimodality approach: intentional reconstruction of the aneurysm neck followed by endovascular coiling. Results: A total of 5 aneurysms were treated, of which 3 were large or giant in size, and 3 were fusiform or multilobulated. Complete angiographic obliteration was confirmed in 4 aneurysms (80%). All patients had a good outcome (Glasgow Outcome Scale score 5; mean follow-up, 64 months). Conclusion: As for complex, surgically intractable aneurysms, the intentional reconstruction of the aneurysm neck followed by endovascular coiling should be considered more often. Copyright (c) 2007 S. Karger AG, Basel.

脳梗塞7例、内頸動脈閉塞4例、AVM3例、脳動脈瘤1例、モヤモヤ病1例の14名16症例を対象に256列面検出器CTプロトタイプを用いた画像検査を行った。CTPの取得を目的とした11例全例で良好なWhole-brain CTP画像が得られ、MSCTによるCTPに比べてより正確な病態の把握が可能であった。16例全例において4Dデータの動脈相から3D-CTAが得られ12例で高分解能のdynamic subtraction 3D-CTAが得られ立体的動態評価が可能であった。寝台移動を行わないためCTPとCTAを高精度に合成できるため灌流情報と血流動態・血管形態の評価を一度に行うことが可能であり、Dynamic-3DCT-DSAでは良好な骨除去による脳血管の詳細な形態情報に加え頭蓋内血行形態をも観察可能であった。

脳動脈解離の診断において最大値投影法による非造影MRAおよびボリュームレンダリング法による三次元(3D)CTAを作成し,それぞれの多断面再構成(MPR)像での観察を行い,動脈解離が疑われた部分の血管内腔および血管壁を評価した.その結果,非造影MRA,3D-CTの両方でMPR像において血栓化した解離腔を確認することが可能であり診断に有用であった.特に前大脳動脈などの細い血管では3D-CTの方が解離腔をより明瞭に描出することが可能であった

Partially thrombosed giant aneurysms are one of the most difficult diseases in the neurosurgical field. We have had 18 of these cases namely, three in vertebral artery, four in basilar artery, four in internal carotid artery, five in middle cerebral artery, and two in anterior communicating artery. Nine aneurysms were clipped, two aneurysms were removed with anastomosis, two cases were treated inter-ventionally, and five cases were treated conservatively because of serpentine and fusiform types of aneurysms in internal carotid artery bifurcation. These conservatively treated patients died due to in-farction. When surgery is selected in the thrombosed giant aneurysms, the approach is the most im-portant to secure the neck. Three-dimensional computed tomography angiography was useful to plan the strategy for surgery. If the neck is big enough for placement of a clip, arterial reconstruction is the choice. The reconstruction must be done including an adequate size of the artery because of the thick wall. If the aneurysm neck is too small to reconstruct, aneurysmectomy with anastomosis is one of the choices.

Recently there have been reports of intracranial dissecting aneurysms. Most authors recommended proximal ligation of the vertebral artery or trapping as the modality of treatment.However, we have had cases in which reconstruction of vertebral arteries with fenestrated clips were performed. Vertebral artery dissecting aneurysms were classified into two groups based on angiograms. One group is the one-side type, which indicates that dissection occurred on one side, and the other is the whole-around type, which points to the progression of the dissection as a whole around the artery. From April 1973 to March 1993 we operated on 1,304 cases of intracranial aneurysms, including 41 vertebral aneurysms. Eleven of the latter were suspected to have dissecting aneurysms based on angiograms and surgery. Six out of 7 cases had one-side type dissecting aneurysms, which were clipped directly and the vertebral arteries were reconstructed. One unsuccessful case had been an aged patient when surgery was done prior to the development of fenestrated clips. Two out of 4 cases had whole-around type aneurysms and underwent proximal clipping and trapping. One case became worse after the second day of trapping because of retrograde thrombosis. Two patients, for whom surgery was contraindicated because of bad neurological condition, died.