hayakawa motoharu

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.

The introduction of 320-row area detector CT (ADCT) has led to a new era in CT. ADCT should not be thought of as conventional CT scanning with a larger number of detector rows. Since the overall width of the detector is greatly expanded, the brain can be scanned in a single rotation. This makes it possible to perform non-contrast CT scanning in a single rotation. ADCT also permits volume data to be acquired along the temporal axis by continuous scanning (4D data). Since scanning can be completed in a single rotation, sedation is not required even in patients who may be difficult to examine, such as pediatric patients and patients with impaired consciousness. Scanning can also be completed in approximately 1 second in routine 3D-CTA studies, permitting the amount of contrast medium to be reduced. In addition, volume data from the arterial phase to the venous phase (4D data) can be acquired by sequential scanning (continuous or intermittent scanning). In particular, since ADCT is superior to DSA in terms of tissue contrast, especially in the venous phase, visualization is improved and three-dimensional assessment can be performed more easily. In addition, ECG-gated continuous volume scanning allows an extensive range from the head through the carotid arteries to the heart (coronary arteries) to be examined in a single scan. Given the strong association between carotid artery stenosis and coronary artery stenosis, the ability to assess both in a single study is of great clinical value. ADCT also supports 160-row helical scanning, which permits the range from the head to the inguinal region to be scanned in approximately 6 seconds. Moreover, since ADCT allows the arteries of the entire body to be examined with no increase in the amount of contrast medium, the range from the location where the sheath is to be introduced to the lesion can be confirmed before neuroendovascular therapy. As discussed above, ADCT has many advantages. However, ADCT studies can generate a huge number of reconstructed images, sometimes reaching several thousand. It is impossible to interpret all of these images individually. In addition, sequential scanning is associated with higher X-ray exposure. It is therefore essential to select the ideal scanning method for the clinical objective, to set the optimal exposure dose, and to perform reconstruction and analysis appropriately.

Objective: The authors present a patient with acute ischemic stroke due to severe stenosis of the left internal carotid artery who was successfully treated with carotid artery stenting (CAS) in the acute stage.Case: A 76-year-old man presented with aphasia and right hemiparesis. Intravenous administration of rt-PA was not indicated because the patient was outside the time-window. As perfusion CT revealed a large ischemic penumbra in the territory of the left middle cerebral artery, we attempted neuroendovascular therapy to rescue the penumbra from infarction. The regional saturation of oxygen (rSO2) was monitored by near-infrared spectroscopy (NIRS) during the procedure. Before the procedure, rSO2 in the left frontal area was decreased by 10% compared with that on the right side. The self-expanding stent was deployed after predilation. Just after deployment, rSO2 on the left side increased by 10% and we intentionally did not perform postdilation to avoid hyperperfusion. The procedure was finished within 6 hours and 30 minutes after ischemic onset. The postoperative course was good and there were no hemorrhagic complications.Conclusion: NIRS monitoring allows observation of real time changes in cerebral perfusion during the dilatative procedure, which provides useful information for intraoperative decision-making on whether stenting should be added after angioplasty and then, whether postdilation should be performed during carotid artery stenting in the acute stage.

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.