Postoperative Magnetic Resonance Angiography Research Articles

A novel intraoperative “Faucet” technique for assessing patency of superficial temporal artery to middle cerebral artery bypass and for prevention of microemboli

PurposeThis technical note introduces the novel faucet technique, which enables neurosurgeons to evaluate the patency of a bypass during superficial temporal artery–middle cerebral artery bypass surgery. The technique is particularly useful when there is a lack of equipment such as micro-Doppler or indocyanine green in the operating rooms. This is often the case in Central Asian countries.MethodsThe faucet technique involves carefully examining the graft by gently opening a valve, comparable to a faucet, to observe the blood flow through the bypassed vessel. Overall, 36 procedures underwent the faucet technique for assessing the superficial temporal artery–middle cerebral artery bypass patency.ResultsThe results indicate that the bypass remained patent in all cases, as confirmed through the intraoperative faucet technique, postoperative magnetic resonance angiography, or cerebral angiography.ConclusionBy visually inspecting the blood flow through the faucet technique, surgeons can confirm the effectiveness of the graft and ensure that the bypass remains unobstructed during the surgery.

Axial Magnetic Resonance Angiography in Evaluating Revascularization after Indirect Bypass Surgery for Moyamoya Axial Magnetic Resonance Angiography after Indirect Bypass

Introduction: At our institution, revascularization after indirect moyamoya surgery is routinely evaluated using magnetic resonance angiography (MRA) rather than catheter angiography. In this paper, we review how revascularization can be visualized on axial MRA and compare its visualization on MRA to that on catheter angiography. We also compare clinical outcomes of patients followed with routine postoperative MRA with outcomes of patients followed with routine catheter angiography. Methods: We retrospectively reviewed the records of all patients treated at our institution who underwent unilateral encephaloduroarteriosynangiosis (EDAS) and/or pial synangiosis between the ages of 1 and 21 years and between December 31, 2003, and May 1, 2021. We included patients who underwent EDAS/pial synangiosis at other hospitals as long as they met all inclusion criteria. Inclusion criteria included having a preoperative MRA within 18 months of surgery and a postoperative MRA 3−30 months after surgery. Clinical outcomes included development of postoperative stroke and transient ischemic attacks (TIAs) and changes in symptoms (improved, unchanged, or worsened), including seizures, balance issues, and headaches. Clinical outcomes were compared between patients who had routine postoperative MRA only versus those who had routine postoperative angiograms, with or without routine MRA. For each surgery, we determined the ratios of the diameters and areas of the donor vessel and the contralateral corresponding vessel, as well as the relative signal intensities of these two vessels, on preoperative and 3- to 30-month postoperative MRA. We did the same for the middle meningeal artery (MMA) ipsilateral to the donor artery and the contralateral MMA. We assessed changes from pre- to post-operation in diameter ratios, area ratios, relative signal intensity, ivy sign, and in brain perfusion on arterial spin labeled (ASL) imaging. MRI and MRA measures of revascularization and flow were compared to Matsushima grades in patients who had postoperative catheter angiograms. Results: Fifty-one operations for 42 unique patients were included. There were no significant differences in the rates of postoperative strokes, postoperative TIAs, changes in symptoms, or new symptoms after surgeries evaluated by routine postoperative MRA versus catheter angiogram (p = 0.282, 1, 0.664, and 0.727, respectively). There were significant associations between greater collateralization on postoperative MRA and greater median increases in preoperative-to-postoperative ratios of donor-vessel-over-contralateral-vessel diameter (p = 0.0461), ipsilateral-MMA-over-contralateral-MMA diameter (p = 0.0135), and the summed donor and ipsilateral MMA diameters over the summed contralateral vessel diameters (p < 0.001). The median increase in the ratio of the donor vessel and contralateral corresponding vessel diameters was significantly higher for Matsushima grade A versus B (p = 0.036). The median increase in the ratio of the sum of donor and ipsilateral MMA diameters over the sum of the contralateral vessel diameters was significantly higher for improved-versus-unchanged perfusion on ASL imaging (p = 0.0074). There was a nonsignificant association between greater postoperative collateralization on MRA and Matsushima grade (p = 0.1160). Conclusion: Cerebral revascularization after EDAS and pial synangiosis can be evaluated on axial MRA by comparing the diameter and/or signal intensity of the donor vessel and corresponding contralateral vessel, as well as the ipsilateral and contralateral MMA, on postoperative-versus-preoperative MRA. The use of routine postoperative MRA rather than catheter angiography does not appear to negatively affect outcomes.

Location matters: Offset in tissue-engineered vascular graft implantation location affects wall shear stress in porcine models

ObjectiveAlthough surgical simulation using computational fluid dynamics has advanced, little is known about the accuracy of cardiac surgical procedures after patient-specific design. We evaluated the effects of discrepancies in location for patient-specific simulation and actual implantation on hemodynamic performance of patient-specific tissue-engineered vascular grafts (TEVGs) in porcine models. MethodsMagnetic resonance angiography and 4-dimensional (4D) flow data were acquired in porcine models (n = 11) to create individualized TEVGs. Graft shapes were optimized and manufactured by electrospinning bioresorbable material onto a metal mandrel. TEVGs were implanted 1 or 3 months postimaging, and postoperative magnetic resonance angiography and 4D flow data were obtained and segmented. Displacement between intended and observed TEVG position was determined through center of mass analysis. Hemodynamic data were obtained from 4D flow analysis. Displacement and hemodynamic data were compared using linear regression. ResultsPatient-specific TEVGs were displaced between 1 and 8 mm during implantation compared with their surgically simulated, intended locations. Greater offset between intended and observed position correlated with greater wall shear stress (WSS) in postoperative vasculature (P < .01). Grafts that were implanted closer to their intended locations showed decreased WSS. ConclusionsPatient-specific TEVGs are designed for precise locations to help optimize hemodynamic performance. However, if TEVGs were implanted far from their intended location, worse WSS was observed. This underscores the importance of not only patient-specific design but also precision-guided implantation to optimize hemodynamics in cardiac surgery and increase reproducibility of surgical simulation.

Ipsilateral late stroke after revascularization surgery for patients with Moyamoya disease.

Ipsilateral late stroke events occurring after cerebral revascularization for Moyamoya disease (MMD) and their risk factors have not been fully investigated. We retrospectively analyzed 123 patients with MMD who underwent 212 revascularizations. We investigated preoperative demographic data, surgical procedures, and ipsilateral stroke events occurring more than 1 month after surgery. The effect of revascularization and the residual Moyamoya vessel (MMV) score were examined using magnetic resonance angiography (MRA). Then, predictive factors for postoperative late stroke occurrence were evaluated by logistic regression. The mean age was 26 ± 18.4 years (range 1 to 66 years). Ipsilateral late stroke events were present in 11 of 123 (9%) patients. Stroke occurred in 11 out of 212 surgeries (5.2%) on a hemispheric basis. During the 1300.1 hemisphere-years of follow-up more than 1 month after surgery, the annual stroke rate was 0.84%. The postoperative MRA time-of-flight image showed a mean revascularization score of 1.82 ± 0.6 and a mean residual MMV score of 1.91 ± 0.83. Postoperative strokes occurring within 1 month after cerebral revascularization (36.4%, p = 0.0026) and lower revascularization scores (1.82 ± 0.6 vs 2.51 ± 0.59, p = 0.0006) were significant factors related to the presence of ipsilateral late stroke. Logistic regression showed that stroke events within 1 month after revascularization (odds ratio [OR], 9.79; 95% confidence interval [CI], 0.02-0.57; p = 0.0103), low revascularization score (OR, 0.15; 95% CI, 0.001-0.37; p = 0.0069), and high residual MMV score (OR, 16.2; 95% CI, 1.88-187.4; p = 0.0107) were risk factors for ipsilateral stroke more than 1 month after revascularization. MMD patients who have a stroke within 1 month after cerebral revascularization are at high risk for late strokes. Less effective revascularization or remarkable residual MMV are risk factors for late stroke events. Additional revascularization may be considered for patients in such situations. This study was approved by the Bioethics Review Committee of Nagoya University Hospital for the treatment and prognosis of Moyamoya disease (2016-0327).

Identification of the Distal End of Carotid Plaque Using 3-Dimensional Fast Spin Echo T1-Weighted Magnetic Resonance Plaque Imaging

Background: Complete removal of the distal end of the plaque is an important requirement in carotid endarterectomy (CEA) to avoid postoperative complication. Preoperative identification of the distal end of plaque contributes to complete plaque removal. Three-dimensional (3D) magnetic resonance (MR) plaque imaging has been widely used to evaluate carotid plaque characterization. The purpose of the present study was to determine whether preoperative 3D fast spin echo (FSE) T1-weighted MR plaque imaging could identify the distal end of carotid plaque. Methods: This study was designed as a prospective cohort study. We examined 50 patients with cervical internal carotid artery (ICA) stenosis who underwent CEA. 3D-FSE T1-weighted MR plaque imaging of the affected carotid bifurcation was preoperatively performed using a 1.5-T scanner. Identification of the distal end of plaque (DEMRI) on MR plaque imaging was performed and the distance from the baseline (DistanceMRI) was measured. Intraoperatively, the superimposed distal end of carotid plaque (Esim) was marked on the ICA according to the measurement on MR plaque imaging. The actual distal end of plaque (DECEA) was then identified after arteriotomy and the difference (DifferenceCEA-MRI) between Esim and DECEA was measured. Contrast ratio of carotid plaque and tortuosity of the ICA were calculated using MR plaque imaging. Results: Interobserver agreements in measurement of DistanceMRI were excellent (intraclass correlation coefficient, .955; 95% confidence interval, .922-.974). In 28 patients (56%), Esim was identical to DECEA. Mean DifferenceCEA-MRI was 1.32 ± 1.77 mm. DifferenceCEA-MRI was significantly greater with fibrotic plaque (4.14 ± 1.21 mm) than with lipid-rich or necrotic plaque (.43 ± .87 mm; P < .05) or hemorrhagic plaque (1.27 ± 1.64 mm; P < .05). Mean DifferenceCEA-MRI was significantly greater in the group with tortuosity of the ICA less than 120° (3.86 ± 1.77 mm) than in the group with greater than or equal to 120° but less than or equal to 150° (1.15 ± 1.51 mm; P < .05) or greater than150° (0.50 ± 1.10 mm; P < .05). No patients showed residual stenosis after surgery on postoperative MR angiography. Conclusions: Using 3D-FSE T1-weighted MR plaque imaging allowed identification of the distal end of carotid plaque and contributed to complete removal of the plaque, although it may be reduced for cases with low-signal-intensity plaque or severe tortuosity of the ICA.

Restoration of periventricular vasculature after direct bypass for moyamoya disease: intra-individual comparison.

While periventricular anastomosis, a unique abnormal vasculature in moyamoya disease, has been studied in relation to intracranial hemorrhage, no study has addressed its change after bypass surgery. The authors sought to test whether direct bypass surgery could restore normal periventricular vasculature. Patients who had undergone direct bypass surgery for moyamoya disease at a single institution were eligible for the study. Baseline, postoperative, and follow-up magnetic resonance angiography (MRA) scans were scheduled before surgery, after the first surgery, and 3 to 6months after contralateral second surgery, respectively. Sliding-thin-slab maximum-intensity-projection coronal MRA images of periventricular anastomoses were scored according to the three subtypes (lenticulostriate, thalamic, and choroidal anastomosis). Baseline and postoperative MRA images were compared to obtain a matched comparison of score changes in the surgical and nonsurgical hemispheres within individuals (intra-individual comparison). Of 110 patients, 42 were identified for intra-individual comparisons. The periventricular anastomosis score decreased significantly in the surgical hemispheres (median, 2 versus 1; p < 0.001), whereas the score remained unchanged in the nonsurgical hemispheres (median, 2 versus 2; p = 0.57); the score change varied significantly between the surgical and nonsurgical hemispheres (p < 0.001). Of the 104 periventricular-anastomosis-positive hemispheres undergoing surgery, 47 (45.2%) were assessed as negative in the follow-up MRA. Among the subtypes, choroidal anastomosis was most likely to be assessed as negative (79.7% of positive hemispheres). Periventricular vasculature can be restored after direct bypass. The likelihood of correction of choroidal anastomosis is a subject requiring further studies.

Intraoperative Resuturing of Occluded Superficial Temporal Artery-Middle Cerebral Artery Anastomoses: Single-Center Retrospective Study.

In superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis, there is a certain risk of intraoperative acute occlusion of the bypass that can cause operative complications. We sought to assess the efficacy of resuturing at the same site after intraoperative acute occlusion of the bypass. In total, 129 STA-MCA anastomosis operations were performed on 125 patients at our institution. The electronic medical records of each patient were reviewed to gather information regarding intraoperative occlusion events, and the operative videos and postoperative radiologic images were also reviewed. Twelve intraoperative acute occlusions were identified. In each case, resuturing was performed after cutting all knots, flushing the thrombus, and trimming the edges of the STAs. In 11 cases, indocyanine green videoangiography and/or Doppler sonography revealed patency during the operation, which was confirmed by postoperative magnetic resonance angiography. None of the 12 cases exhibited high-signal intensities in the MCA area on diffusion-weighted images. If intraoperative acute occlusion of STA-MCA anastomosis occurs, reanastomosis at the site should be the first option.

One Case of Suspected Angiostenosis Revealed by MRA Following Carotid Endarterectomy Due to a Rare Cause

We herein report on a case in which magnetic resonance angiography (MRA) following carotid endarterectomy revealed the appearance of angiostenosis due to an artifact of metallic powder, which was thought to have come from an old surgical instrument. The patient was a 77-year-old male. Carotid endarterectomy (CEA) was performed for stenosis in the internal carotid artery of his left neck (82%). Upon observing a decline in renal function following CEA surgery, a postoperative cervical MRA revealed the appearance of high-grade stenosis at the common carotid artery on which surgery was performed. No stenosis was revealed upon carotid ultrasonography and angiography. In the original MRA image, an orbicular low intensity area was observed in concordance with the narrow segment. 3D computed tomography (3D-CT) revealed a metallic finding, suggesting it was an artifact caused by metal powder. Close inspection of the metal surgical instruments used during surgery revealed slight damage to a suture snare which had been used for 30 years. Going forward, it is necessary to pay attention to old surgical instruments, introduce a system by which the number of years and the frequency of use of each surgical instrument can be learned, and replace them with new equipment as necessary.

Computational fluid dynamic comparison between patch-based and primary closure techniques after carotid endarterectomy

ObjectiveThe aim of the study was to provide, by means of computational fluid dynamics, a comparative analysis after carotid endarterectomy (CEA) between patch graft (PG) and primary closure (PC) techniques performed in real carotid geometries to identify disturbed flow conditions potentially involved in the development of restenosis. MethodsEight carotid geometries in seven asymptomatic patients who underwent CEA were analyzed. In six cases (A-F), CEA was performed using PG closure; in two cases (G and H), PC was performed. Three-dimensional carotid geometries, derived from postoperative magnetic resonance angiography, were reconstructed, and a computational fluid dynamics analysis was performed. A virtual scenario with PC closure was designed in patients in whom PG was originally inserted and vice versa. This allowed us to compare for each patient hemodynamic effects in the PG and PC scenarios in terms of oscillatory shear index (OSI) and relative residence time (RRT), considered indicators of disturbed flow. ResultsFor the six original PG cases, the mean averaged-in-space OSI was 0.07 ± 0.01 for PG and 0.03 ± 0.02 for virtual-PC (difference, 0.04 ± 0.01; P = .0016). The mean of the percentage of area (%A) with OSI >0.2 resulted in 10.08% ± 3.38% for PG and 3.80% ± 3.22% for virtual-PC (difference, 6.28 ± 1.91; P = .008). For the same cases, the mean of the averaged-in-space RRT resulted in 5.48 ± 3.40 1/Pa for PG and 2.62 ± 1.12 1/Pa for virtual-PC (difference, 2.87 ± 1.46; P = .097). The mean of %A RRT >4.0 1/Pa resulted in 26.53% ± 12.98% for PG and 9.95% ± 6.53% for virtual-PC (difference, 16.58 ± 5.93; P = .025). For the two original PC cases, the averaged-in-space OSIs were 0.02 and 0.04 for PC and 0.03 and 0.02 for virtual-PG; the %A OSIs >0.2 were 0.9% and 7.6% for PC and 3.0% and 2.2% for virtual-PG; the averaged-in-space RRTs were 1.8 and 2.0 1/Pa for PC and 2.9 and 1.9 1/Pa for virtual-PG; the %A RRTs >4.0 1/Pa were 6.8% and 9.8% for PC and 9.4% and 6.2% for virtual-PG. These results revealed generally higher disturbed flows in the PG configurations with respect to the PC ones. ConclusionsOSI and RRT values were generally higher in PG cases with respect to PC, especially for high carotids or when the arteriotomy is mainly at the bulb region. Thus, an elective use of patch should be considered to prevent disturbed flows.

人工血管を用いて再建を行った高齢者頚動脈感染性動脈瘤の1例

An 89-year-old man presented to our hospital with a pulsatile mass in his neck. Based on magnetic resonance imaging (MRI) and blood tests, he was diagnosed as having an infected aneurysm of the right carotid artery bifurcation. Conservative therapy with antibiotic use was initiated. However, the aneurysm was found to rapidly increase in size. We decided to repair the culprit vessel walls because of the risk of lethal rupture. The aneurysm extended between the common carotid artery (CCA) and internal carotid artery (ICA). Strong adhesions were noted between the walls of the aneurysm and surrounding structures. The wall was difficult to dissect and showed leakage of blood, indicating vascular injury. Thus, resection of the CCA, ICA and external carotid artery (ECA) was performed, followed by reconstruction using a synthetic graft. The patient demonstrated no neurological deficit postoperatively, and postoperative magnetic resonance angiography (MRA) and MRI revealed a patent graft and no new ischemic lesion. Conservative therapy maintained his general condition without any vascular event. Extracranial aneurysms of the carotid artery without any associated history of traumatic events are rare. We discuss the treatment strategy for this condition based on previous reports.

Heterotopic vascularized lymph node transfer to the medial calf without a skin paddle for restoration of lymphatic function: Proof of concept.

The use of heterotopic vascularized lymph node transfer (HVLNT) for the treatment of lower extremity lymphedema is still evolving. Current techniques, either place the lymph nodes in the thigh without a skin paddle or at the ankle requiring an unsightly and often bulky skin paddle for closure. We explored the feasibility of doing a below-knee transfer without a skin paddle using the medial sural vessels as recipient vessels and report our experience in 21 patients. A retrospective review of all patients who underwent HVLNT to the medial calf was performed. Postoperative magnetic resonance angiography (MRA) and lymphoscintigraphy (LS) were analyzed to assess lymph node viability and function after transfer. Twenty-one patients underwent HVLNT to the medial calf. Postoperative imaging was performed at an average of 11 months after surgery. Thirteen patients had postoperative MRA, of whom 12 demonstrated viable lymph nodes. Seven patients underwent postoperative LS, of whom three demonstrated uptake in the transferred nodes. In the other four patients, the injectate failed to reach the level of the proximal calf. We provide proof of concept that HVLNT to the lower leg using the medial sural vessels without a skin paddle can result in viable and functional lymph nodes in the setting of lower extremity lymphedema. J. Surg. Oncol. 2017;115:90-95. © 2016 Wiley Periodicals, Inc.

The use of fibrin and gelatin fixation to repair a kinked internal carotid artery in carotid endarterectomy

Background:The kinking of the internal carotid artery (ICA) after final closure in carotid endarterectomy (CEA) is thought to be uncommon. When it occurs, it is mandatory to reconstruct ICA to preserve normal blood flow. We herein present a case in which a fixation technique was applied to repair an ICA that became kinked during CEA.Case Description:A 68-year-old man presented with cerebral infarction due to an artery-to-artery embolism from the right cervical ICA stenosis. CEA was performed 12 days after admission. After final closure, a distal portion of ICA was found to have been kinked following plaque resection in CEA procedure. Fixation with fibrin glue and gelatin was used to reinforce the arterial wall and repair the kink. Postoperative magnetic resonance angiography demonstrated the release of the kink in ICA.Conclusion:Fixation with fibrin and gelatin is a salvage armamentarium that can be considered in CEA for the repair of kinked or tortuous ICA.

内頚動脈前壁動脈瘤破裂に対する高灌流EC-IC bypass/動脈瘤トラッピング術後急性期の脳循環動態とMR所見の検討

Background: Extracranial-intracranial (EC-IC) bypass is a powerful tool for treating complex cerebral aneurysm. Ruptured aneurysms at the non-branching site of the internal carotid artery (ICA), the so-called blister-like aneurysm, have been treated with high flow EC-IC bypass and aneurysmal trapping, but postoperative cerebral hemodynamics following flow conversion have remained unclear. Methods: The present study investigated six cases with ruptured blister-like ICA aneurysm, who were managed by high flow EC-IC (ECA-M2 or CCA-M2) bypass using interposed saphenous vein graft followed by microsurgical aneurysmal trapping. Postoperative cerebral blood flow (CBF) was evaluated by N-isopropyl-p-[123I]iodoamphetamine single-photon emission computed tomography (SPECT) in the acute stage. Routine magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were also performed in the acute stage. Results: No patient suffered from intra-operative aneurysmal rupture, and no patient manifested procedure-related ischemic complications. Postoperative SPECT in the acute stage (1‐3 days after surgery) demonstrated a mild decrease in CBF in the operated hemisphere. Postoperative MRA demonstrated apparently patent EC-IC bypass in all cases. One patient manifested a delayed vasospasm and required a diagnostic angiogram and an intra-arterial infusion of fasudil hydrochloride. The clinical outcome was as follows: GR (good recovery) in four patients, and MD (moderately disabled) in two patients. Conclusion: High flow EC-IC bypass followed by aneurysmal trapping (ICA trapping) was found to be a safe and effective treatment for ruptured blister-like ICA aneurysm. We recommend postoperative SPECT and MRI/MRA in the acute stage to monitor cerebral hemodynamics after flow conversion.

Analysis of ischemic cerebral lesions using 3.0-T diffusion-weighted imaging and magnetic resonance angiography after revascularization surgery for ischemic disease

BackgroundCerebral revascularization surgery (CRS) is increasingly recognized as an important component in the treatment of complex cerebral vascular disease and tumors. CRS requires that the incidence of perioperative neurological complications should be minimized, because CRS for ischemic disease is often not the goal of treatment, but rather a prophylactic surgery. CRS carries the risk of focal postoperative neurological deficits. Little has been established concerning mechanisms of post-CRS ischemia. We used 3.0-T diffusion-weighted magnetic resonance imaging (DWI) and magnetic resonance angiography (MRA) to analyze the incidence and mechanism of ischemic lesions. MethodsWe studied the anterior circulation territory after 20 CRS procedures involving 33 vascular anastomosis procedures (13 double anastomoses and 7 single anastomoses) in 12 men and 8 women between June 2007 and October 2011. The operations included single or double superficial temporal artery–middle cerebral artery (STA–MCA) anastomosis to treat internal carotid artery/MCA occlusions or severe MCA stenosis. A combined STA–MCA anastomosis and indirect bypass were performed for moyamoya disease. Postoperative DWI and MRA were obtained in all patients between 24 and 96h after surgery to detect thromboembolism, hypoperfusion, or procedural ischemic complications and vasospasms of the donor STA. ResultsFollow-up DWI and MRA were carried out 1.8±0.6 days after CRS (range, 1–4 days). Temporary occlusion time for anastomoses averaged 18.9min (range, 16–32min). Asymptomatic new hyperintensities occurred in the ipsilateral hemisphere of 2 patients on postoperative DWI (10% patients/6.0% anastomoses), and 1 moyamoya patient (5.0% patients/3.0% anastomoses) developed a symptomatic hyperintensity in the ipsilateral occipital lobe in response to the operation. Two abnormal small (<5mm) cortical DWI lesions were caused by sacrifices of a small branch of the recipient MCA. ConclusionThis study is the first postoperative 3.0-T DWI study of CRS and related clinical events. The incidence of symptomatic postoperative DWI abnormalities was restricted to 1 moyamoya patient representing 5.0% of total patients and 3.0% anastomoses. Although some postoperative DWI abnormalities occurred, CRS was found to be safe with a low risk of symptomatic ischemia.

脳血管バイパス術 内頚動脈系閉塞性脳血管病変に対するＳＴＡ‐ＭＣＡ ｂｙｐａｓｓ術後の急性期画像評価

Superficial temporal artery-middle cerebral artery (STA-MCA) bypass for steno-occlusive cerebrovascular disease prevents future ischemic stroke by improving cerebral blood flow (CBF). Cerebral ischemia and hyperperfusion are potential complications of this procedure during the early postoperative period. We designed this study to investigate the efficacy of neuroradiological evaluation during early postoperative period after revascularization to detect postoperative pathological conditions of the brain and to avoid these complications. Eight consecutive patients (7 men and 1 woman; mean age 62.6 years) suffering from cerebral ischemia due to occlusive cerebrovascular disease with hemodynamic compromise were enrolled in this study. The underlying pathological condition was internal carotid artery (ICA) or MCA occlusion in 7 cases and MCA severe stenosis in 1 case. The standard STA-MCA bypass was performed for all cases. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) were performed on the day after surgery, and single photon emission computed tomography (SPECT) was performed 1 and 7 days after surgery. Postoperative MRA on Day 1 showed patency of the bypass in all cases. Postoperative MRI on Day 1 revealed no ischemic or hemorrhagic complications in any of the cases. Postoperative SPECT showed transient focal intense increase in CBF around the sites of anastomosis in all 8 cases. Intensive blood pressure control was performed to prevent symptomatic hyperperfusion. All cases were discharged without perioperative complications with an average of 19.8 days of postoperative hospital stay. Neuroradiological evaluation during the early postoperative period enables safe perioperative management by revealing underlying pathological conditions of the brain following revascularization surgery.

Intraoperative assessment of anterior circulation aneurysms using the indocyanine green video angiography technique

We performed a prospective study to evaluate the intraoperative value of indocyanine green (ICG) video angiography in anterior circulation aneurysms. From January 2007 to April 2008, 42 patients with anterior circulation aneurysms who were to undergo aneurysm clipping were enrolled in the study. Intraoperative ICG video angiography was performed using a fluorescence microscope. After the operation, three-dimensional CT angiography (CTA), digital substraction angiography (DSA) and magnetic resonance angiography (MRA) were used to evaluate the use of intraoperative ICG video angiography. Of the 42 patients, on ICG video angiography after initial clip placement, neck remnants of the aneurysm were found in two patients, inadvertent clipping of branching vessels in one patient, and inadvertent clipping of perforating vessels in two patients. ICG video angiography after adjustment of the clip position showed a perfect residual elimination with no abnormal findings. Post-operative DSA, CTA and MRA results corresponded to the intraoperative ICG video angiography findings. Therefore, ICG video angiography is an important tool to monitor residual aneurysm, parent artery stenosis or perforating artery occlusion during intracranial aneurysm clipping.

Magnetic resonance angiography of collateral blood supply to spinal cord in thoracic and thoracoabdominal aortic aneurysm patients

Preservation of spinal cord blood supply during descending thoracic (TAA) and thoracoabdominal aortic aneurysm (TAAA) surgery is mandatory to prevent neurologic complications. Although collateral arteries have been identified occasionally and are considered crucial for maintaining spinal cord function in the individual patient, their critical functionality is poorly understood and very little experience exists with visualization. This study investigated whether the preoperative and postoperative presence or absence of collateral arteries detected by magnetic resonance angiography (MRA) is related to spinal cord function during the intraoperative exclusion of the segmental supply to the Adamkiewicz artery. Spinal cord MRA was used to localize the Adamkiewicz artery and its segmental supplier in 85 patients scheduled for open elective surgery for TAA or TAAA. The segmental artery to the Adamkiewicz artery was inside the cross-clamped aortic area in 55 patients, and spinal cord supply was consequently dependent on collateral supply. In these 55 patients the presence of collaterals originating from arteries outside the cross-clamped aortic segment was related to changes in the intraoperative motor-evoked potentials (MEPs) that occurred before corrective measures. Twenty-one patients returned for postoperative MRA. A highly significant (P < .0015) relation was found between the presence of collaterals and intraoperative spinal cord function. In 30 of 31 patients (97%) in whom collaterals were identified, MEPs remained stable. The collaterals in most patients originated caudally to the distal clamp (eg, from the pelvic arteries), which were perfused by means of extracorporeal circulation during cross-clamping. The MEPs declined in 9 of 24 patients (38%) in whom no collaterals were preoperatively visualized. Postoperatively, the 21 patients who had MRA, including 10 in whom preoperatively no collaterals were found, displayed a well-developed collateral network. Collateral arteries supplying the spinal cord can be systematically visualized using MRA. Spinal cord blood supply during open aortic surgery may crucially depend on collateral arteries. Preoperatively identified collateral supply was 97% predictive for stable intraoperative spinal cord function. Patients in whom no collaterals can be depicted preoperatively are at increased risk for spinal cord dysfunction.

Surgical removal of intramuscular arteriovenous hemangioma of the upper left forearm compressing radial nerve branches

The authors report on the case of a 32-year-old woman with an intramuscular arteriovenous hemangioma (AVH) of the left forearm with burning pain and paresthesias diffused to the radial nerve-related territories. The patient underwent coil embolization of the AVH and surgical removal of the remnant and regrown AVH. This case demonstrates the safety and efficacy of surgery when interventional radiology fails to achieve complete occlusion. En bloc removal of the lesion was performed through a left elbow cleft incision, and intraoperative electrophysiological monitoring and angiography with indocyanine green (ICG) were performed. The pathological diagnosis was intramuscular AVH. Postoperative follow-up examinations demonstrated the permanent disappearance of the subcutaneous mass and of the patient's sensory disturbances. Complete excision of the AVH was confirmed on postoperative magnetic resonance angiography, and no surgery-related complications or new neurological symptoms were detected. Intramuscular AVHs are rare lesions that can be successfully treated with both coil endovascular embolization and surgery; the latter is indicated when endovascular procedures fail to occlude the AVH completely. Intraoperative angiography with ICG can be helpful in confirming the success of the procedure.

An impending rupture of a celiac artery aneurysm in a patient with Behçet’s disease — Extra-anatomic aorto-common hepatic artery bypass: Report of a case

A celiac artery aneurysm associated with Behçet's disease is extremely rare. We herein present the case of successful surgical treatment for an impending rupture of a large celiac artery aneurysm with a wide proximal neck in a patient associated with Behçet's disease. To our knowledge, this is the first report of a procedure involving extra-anatomic aorto-common hepatic artery (CHA) bypass through the retroperitoneal space implanting a 6-mm expanded polytetrafluoroethylene graft. An 18-month postoperative magnetic resonance angiography scan showed a good patency of the aorto-CHA graft without an anastomotic pseudoaneurysm in a closure of aorta and anastomoses.

Incorrect Shunt Placement Due to Anatomic Variations of the Aortic Arch During Carotid Endarterectomy: A Rare Cause of Perioperative Ischemia?

To the Editor: Though shunt insertion limits interruption of blood flow during carotid thromboendarterectomy (CTEA), the procedure itself may provoke stroke, usually by air or plaque embolism (1). We report a previously undescribed potential cause of cerebral hypoperfusion during shunting: occlusion of the brachiocephalic trunk during left CTEA due to an anatomic aortic arch variation. A 71-yr-old woman underwent left CTEA under general anesthesia. Insertion of a right radial artery catheter was uneventful. After carotid artery cross-clamping and shunt insertion, we noted loss of the right radial pulse pressure. Her arterial blood pressure, assessed by an oscillometric blood pressure cuff placed on the left arm, remained unchanged. No compression or kinking of the catheter-tubing-transducer system was noticed, and fast-flushing did not show signs of under- or over-damping. Patch angioplasty was completed uneventfully, with normal electroencephalogram tracings. Immediately after shunt removal, her right arterial pressure regained its original shape and correlated with the values assessed by the cuff on the left arm. An anatomic variation of the aortic arch was suspected: subsequent postoperative magnetic resonance angiography confirmed the left common carotid emerging from the innominate trunk (Fig. 1). No postoperative neurological deficiency was noted.Figure 1.: MRA showing the left common carotid emerging from the brachiocephalic trunk. LCCA = left common carotid artery, BCT = brachiocephalic trunk, RCCA = right common carotid artery, RScA = right subclavian artery.Since up to 20% of patients present with aortic arch variation, unintentional occlusion of adjacent vessels and subsequent ischemia may occur during shunt procedures (2). Loss of radial pressure tracing demonstrated subobstruction of the right subclavian artery. We do not know whether the balloon was located in the subclavian artery or more proximal, in the brachiocephalic trunk. As no reflux of blood occurred in the operative field, occlusion of the brachiocephalic trunk seems more likely, potentially causing right cerebral hemisphere hypoperfusion in patients with inadequate redistribution of cerebral blood flow through the circle of Willis. To our knowledge, no case of stroke due to balloon obstruction of the opposite common carotid has been reported, and contralateral stroke remains exceptional. Indeed, during the North American Symptomatic Carotid Endarterectomy Trial (3), only one patient in 1415 awoke with a transient deficit in the contralateral carotid territory. Marc Koch, MD Marco Cristiani, MD Denis Schmartz, MD Department of Cardiothoracic and Vascular Anesthesiology Erasme University Hospital Free University of Brussels Brussels, Belgium [email protected]