Endovascular Coil Embolization of Very Small Intracranial Aneurysms

Objective

We aimed to evaluate the results of endovascular coil embolization for very small aneurysms (≤ 3 mm).

Materials and Methods

Between March 2005 and December 2008, a total of 31 very small aneurysms in 30 patients were treated by coil embolization. Of the 31 aneurysms, five (16%) were ruptured, as opposed to 26 (84%) that were not. We assessed the procedural complications, immediate angiographic outcome after coiling, clinical outcome, and follow-up MR angiography (MRA).

Results

Two thromboembolic complications occurred during the procedure, but did not lead to any persistent neurologic deficit. No procedural aneurysmal rupture was observed and procedure-related morbidity and mortality were both 0%. Occlusion was adequate in 25 aneurysms (81%) and incomplete in six aneurysms (19%). The clinical outcomes of five patients with ruptured aneurysms were good (Glasgow outcome scale ≥ 4), with no bleeding of the treated aneurysms during a mean follow-up period of 13.3 months. On 27 follow-up MRA, there was no recurrence, and the five incompletely occluded aneurysms showed a spontaneous amelioration resulting in an adequate occlusion.

Conclusion

Coil embolization of very small aneurysms is technically feasible with good results. The long-term efficacy and the potential as a standard treatment strategy remain to be determined by randomized large trials.     

Use of Triple Microcatheters for Endovascular Treatment of Wide-Necked Intracranial Aneurysms: A Single Center Experience

Objective

The dual microcatheter technique is common practice for coil embolization of a wide-necked aneurysm, due to safety and efficacy. However, technical limitations of some complex configurations may necessitate additional microcatheters to bolster coil stability, compact the coil, or for protection. Described herein is a triple microcatheter technique for endovascular management of wide-necked intracranial aneurysms.

Materials and Methods

Data accruing prospectively between January 2006 and October 2014 on simultaneously executed triple microcatheter coil embolization procedures done in 38 saccular aneurysms were reviewed. Clinical and morphological outcomes were assessed, with emphasis on technical aspects of treatment.

Results

The triple microcatheter technique was successfully applied to all 38 saccular aneurysms, involving the posterior communicating artery (n = 13), the middle cerebral artery (n = 10), the basilar tip (n = 7), the anterior cerebral artery (n = 5), and the internal carotid artery (n = 3). Stent protection was added in four patients and balloon remodeling in one. Dual microcatheters (n = 24) were usually deployed to deliver the coil within sacs of aneurysms, with the additional microcatheter used for protection. Otherwise, triple microcatheters were deployed for coil delivery (n = 11) or coils were delivered via a single microcatheter, with dual microcatheters deployed for protection (n = 3). Successful occlusion of aneurysms was achieved in 89.5% of cases, with no procedure-related morbidity or mortality. Stable occlusion was maintained in 72.2% (26/36) of the aneurysms at the final follow-up (mean interval, 30.2 ± 22.7 months).

Conclusion

The outcomes of this limited study suggest that the triple microcatheter technique may be an effective and safe therapeutic option for wide-necked aneurysms, using technical strategies tailored to complex angio-anatomic configurations.     

Endovascular Treatment of Traumatic Pseudoaneurysm Presenting as Intractable Epistaxis

Objective

To investigate the clinical efficacy of individual endovascular management for the treatment of different traumatic pseudoaneurysms presenting as intractable epistaxis.

Materials and Methods

For 14 consecutive patients with traumatic pseudoaneurysm presenting as refractory epistaxes, 15 endovascular procedures were performed. Digital subtraction angiography revealed that the pseudoaneurysms originated from the internal maxillary artery in eight patients; and all were treated with occlusion of the feeding artery. In six cases, they originated from the internal carotid artery (ICA); out of which, two were managed with detachable balloons, two with covered stents, one by means of cavity embolization, and the remaining one with parent artery occlusion. All of these cases were followed up clinically from six to 18 months, with a mean follow up time of ten months; moreover, three cases were also followed with angiography.

Results

Complete cessation of bleeding was achieved in all the 15 instances (100%) immediately after the endovascular therapies. Of the six patients who suffered from ICA pseudoaneurysms, one presented with a permanent stroke and one had an episode of rebleeding requiring intervention.

Conclusion

In patients presenting with a history of craniocerebral trauma, traumatic pseudoaneurysm must be considered as a differential diagnosis. Individual endovascular treatment is a relatively safe, plausible, and reliable means of managing traumatic pseudoaneurysms.     

In Vitro Observation of Air Bubbles during Delivery of Various Detachable Aneurysm Embolization Coils

Objective

Device- or technique-related air embolism is a drawback of various neuro-endovascular procedures. Detachable aneurysm embolization coils can be sources of such air bubbles. We therefore assessed the formation of air bubbles during in vitro delivery of various detachable coils.

Materials and Methods

A closed circuit simulating a typical endovascular coiling procedure was primed with saline solution degassed by a sonification device. Thirty commercially available detachable coils (7 Axium, 4 GDCs, 5 MicroPlex, 7 Target, and 7 Trufill coils) were tested by using the standard coil flushing and delivery techniques suggested by each manufacturer. The emergence of any air bubbles was monitored with a digital microscope and the images were captured to measure total volumes of air bubbles during coil insertion and detachment and after coil pusher removal.

Results

Air bubbles were seen during insertion or removal of 23 of 30 coils (76.7%), with volumes ranging from 0 to 23.42 mm³ (median: 0.16 mm³). Air bubbles were observed most frequently after removal of the coil pusher. Significantly larger amounts of air bubbles were observed in Target coils.

Conclusion

Variable volumes of air bubbles are observed while delivering detachable embolization coils, particularly after removal of the coil pusher and especially with Target coils.     

Follow-up of true visceral artery aneurysm after coil embolization by three-dimensional contrast-enhanced MR angiography

PURPOSE

We aimed to evaluate the outcomes of coil embolization of true visceral artery aneurysms by three-dimensional contrast-enhanced magnetic resonance (MR) angiography.

MATERIALS AND METHODS

We used three-dimensional contrast-enhanced MR angiography, which included source images, to evaluate 23 patients (mean age, 60 years; range, 28–83 years) with true visceral artery aneurysms (splenic, n=15; hepatic, n=2; gastroduodenal, n=2; celiac, n=2; pancreaticoduodenal, n=1; gastroepiploic, n=1) who underwent coil embolization. Angiographic aneurysmal occlusion was revealed in all cases. Follow-up MR angiography was conducted with either a 1.5 or 3 Tesla system 3–25 months (mean, 18 months) after embolization. MR angiography was evaluated for aneurysmal occlusion, hemodynamic status, and complications.

RESULTS

Complete aneurysmal occlusion was determined in 22 patients (96%) on follow-up MR angiography (mean follow-up period, 18 months). Neck recanalization, which was observed at nine and 20 months after embolization, was confirmed in one of eight patients (13%) using a neck preservation technique. In this patient, a small neck recanalization covered by a coil mass was demonstrated. The complete hemodynamic status after embolization was determined in 21 patients (91%); the visualization of several collateral vessels, such as short gastric arteries, after parent artery occlusion was poor compared with that seen on digital subtraction angiography in the remaining two patients (9%). An asymptomatic localized splenic infarction was confirmed in one patient (4%).

CONCLUSION

Our study presents the follow-up results from three-dimensional contrast-enhanced MR angiography, which confirmed neck recanalization, the approximate hemodynamic status, and complications. This effective and less invasive method may be suitable for serial follow-up after coil embolization of true visceral aneurysms.True visceral artery aneurysms are a rare and uncommon form of vascular disease often found incidentally in 0.09% to 2% of the general population (1–3). However, these true aneurysms have an incidence of rupture and mortality rate of 20% to 75% due to life-threatening hemorrhage (4, 5). Aneurysms can be saccular or fusiform. Endovascular treatment of true visceral artery aneurysms using coil embolization has been reported as an invasive and effective procedure to prevent rupture (6).Various modalities have been used as follow-up evaluation methods after coil embolization of visceral artery aneurysms, including computed tomography (CT), magnetic resonance (MR) angiography, ultrasonography (US), and digital subtraction angiography (DSA) (6, 7). However, specific methods and the ideal follow-up times after coil embolization of visceral artery aneurysms are not well established. Coil embolization of visceral artery aneurysms occasionally result in neck recanalization, growth of a residual aneurysm neck or body remnant, organ infarction, and coil migration (7–9). In particular, one group reported that neck recanalization was effectively followed up by three-dimensional (3D) contrast-enhanced MR angiography (CEMR angiography) (8).The aim of the present study was to evaluate the outcomes of coil embolization of true visceral artery aneurysms and to assess the role of 3D CEMR angiography as a follow-up method.     

Percutaneous Access via the Recanalized Paraumbilical Vein for Varix Embolization in Seven Patients

Objective

To evaluate the feasibility of percutaneous access via the recanalized paraumbilical vein for varix embolization.

Materials and Methods

Between July 2008 and Jan 2014, percutaneous access via the recanalized paraumbilical vein for varix embolization was attempted in seven patients with variceal bleeding. Paraumbilical vein puncture was performed under ultrasonographic guidance, followed by introduction of a 5-Fr sheath. We retrospectively evaluated the technical feasibility, procedure-related complications, and clinical outcomes of each patient.

Results

Recanalized paraumbilical vein catheterization was performed successfully in all patients. Gastroesophageal varix embolization was performed in six patients, and umbilical varix embolization was performed in one patient. Embolic materials used are N-butyl cyanoacrylate (n = 6) and coil with N-butyl cyanoacrylate (n = 1). There were no procedure-related complications. One patient underwent repeated variceal embolization 6 hours after initial procedure via recanalized paraumbilical vein, due to rebleeding from gastric varix.

Conclusion

Percutaneous access via the paraumbilical vein for varix embolization is a simple alternative in patients with portal hypertension.     

Time-Resolved 3D Contrast-Enhanced MRA on 3.0T: a Non-Invasive Follow-Up Technique after Stent-Assisted Coil Embolization of the Intracranial Aneurysm

Objective

To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA.

Materials and Methods

TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method.

Results

The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively.

Conclusion

4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.     

Apparent diffusion coefficient measurements to support a diagnosis of intracranial hypotension

Objective:

Intracranial hypotension (ICH) can be a challenging diagnosis, as cerebrospinal fluid leaks may be difficult to confirm, patients may have other causes for clinical symptoms and imaging findings can be non-specific, particularly in the setting of comorbidities. We investigate the use of brain diffusion measurements [apparent diffusion coefficient (ADC) values] in the assessment of ICH.

Methods:

13 cases of ICH were identified retrospectively based on imaging findings and their clinical histories were compared with 13 control subjects. Regional ADC values and average diffusion constant (D_av) from brain slice ADC histograms were measured.

Results:

ADC values trended higher in all brain regions in patients with ICH than those in control subjects, with statistically significant differences in frontal white matter, mid-brain and deep grey structures. D_av determined by a single-slice ADC histogram was significantly higher in patients with ICH than in the control group (p = 0.008). In two cases followed longitudinally, D_av correlated with the patient''s symptoms and decreased towards normal value with blood patch. In one case, decreased D_av correlated with the formation of subdural collections.

Conclusion:

Cerebral oedema as assessed by increased ADC is strongly correlated with ICH (10 of 13 cases). Histographic analysis of ADC values may offer increased accuracy of ADC measurement. ADC value assessment in the determination of ICH may be particularly useful in complex clinical cases, where treatment is followed over time or where gadolinium is not used and meningeal enhancement cannot be assessed.

Advances in knowledge:

This article investigates the use of brain diffusion measurements in the assessment of ICH in the clinical setting.Intracranial hypotension (ICH) can be a difficult diagnosis, and the sensitivity and specificity of cranial imaging for diagnosis of ICH is unknown. Making a diagnosis of ICH can be particularly difficult in complex cases such as patients with craniotomy or shunt, chronic migraine, or systemic disease such as human immunodeficiency virus (HIV) or cancer. Current diagnostic criteria include invasive procedures such as myelography, cerebrospinal fluid (CSF) pressure studies and response to blood patch. Additional imaging hallmarks of ICH may aid in making a more definitive diagnosis non-invasively.Depletion of CSF results in decreased spinal fluid pressure. As CSF pressure drops, compensatory mechanisms, including venous engorgement and the formation of subdural collections, can occur; phenomena that have been explained by the Monro–Kellie hypothesis.¹ These compensatory phenomena can be seen at imaging as diffuse, smooth dural thickening and enhancement, pituitary engorgement and extra-axial collections and are used to suggest the diagnosis of ICH at imaging. Each of the classic imaging findings are non-specific, and ICH has even been reported in the absence of imaging findings.^1,2 Cerebral oedema also occurs in ICH and may result from tissue fluid retention as a consequence of the Monro–Kellie hypothesis, but may also be explained by venous outflow obstruction as a result of brain “sag”.³ Diffusivity measurements have been used as a surrogate marker for cerebral oedema.^4–6 We aimed to test a hypothesis that ADC value measurements from routine clinical MR scans can be used to measure cerebral oedema in ICH and can be used to support a diagnosis of ICH.     

Preoperative Coil Embolization of Side Branches and Postoperative Antifibrinolytic Therapy in Endovascular Aneurysm Repair: A Propensity Score Analysis

Purpose

To demonstrate feasibility and efficacy of preoperative coil embolization of side branches and postoperative tranexamic acid (TXA) therapy for management of type II endoleak and aneurysmal sac regression after endovascular aortic repair (EVAR).

Internal Iliac Artery Embolization during an Endovascular Aneurysm Repair with Detachable Interlock Microcoils

Objective

The purpose of this study was to evaluate the effectiveness of detachable interlock microcoils for an embolization of the internal iliac artery during an endovascular aneurysm repair (EVAR).

Materials and Methods

A retrospective review was conducted on 40 patients with aortic aneurysms, who had undergone an EVAR between January 2010 and March 2012. Among them, 16 patients were referred for embolization of the internal iliac artery for the prevention of type II endoleaks. Among 16 patients, 13 patients underwent embolization using detachable interlock microcoils during an EVAR. Computed tomographic angiographies and clinical examinations were performed during the follow-up period. Technical success, clinical outcome, and complications were reviewed.

Results

Internal iliac artery embolizations using detachable interlock microcoils were technically successful in all 13 patients, with no occurrence of procedure-related complications. Follow-up imaging was accomplished in the 13 cases. In all cases, type II endoleak was not observed with computed tomographic angiography during the median follow-up of 3 months (range, 1-27 months) and the median clinical follow-up of 12 months (range, 1-27 months). Two of 13 (15%) patients had symptoms of buttock pain, and one patient died due to underlying stomach cancer. No significant clinical symptoms such as bowel ischemia were observed.

Conclusion

Internal iliac artery embolization during an EVAR using detachable interlock microcoils to prevent type II endoleaks appears safe and effective, although this should be further proven in a larger population.     

Percutaneous Transabdominal Approach for the Treatment of Endoleaks after Endovascular Repair of Infrarenal Abdominal Aortic Aneurysm

Objective

The purpose of this study was to evaluate the technical feasibility and clinical efficacy of percutaneous transabdominal treatment of endoleaks after endovascular aneurysm repair.

Materials and Methods

Between 2000 and 2007, six patients with type I (n = 4) or II (n = 2) endoleaks were treated by the percutaneous transabdominal approach using embolization with N-butyl cyanoacrylate with or without coils. Five patients underwent a single session and one patient had two sessions of embolization. The median time between aneurysm repair and endoleak treatment was 25.5 months (range: 0-84 months). Follow-up CT images were evaluated for changes in the size and shape of the aneurysm sac and presence or resolution of endoleaks. The median follow-up after endoleak treatment was 16.4 months (range: 0-37 months)

Results

Technical success was achieved in all six patients. Clinical success was achieved in four patients with complete resolution of the endoleak confirmed by follow-up CT. Clinical failure was observed in two patients. One eventually underwent surgical conversion, and the other was lost to follow-up. There were no procedure-related complications.

Conclusion

The percutaneous transabdominal approach for the treatment of type I or II endoleaks, after endovascular aneurysm repair, is an alternative method when conventional endovascular methods have failed.     

Coil embolization in precommunicating (A1) segment aneurysms of anterior cerebral artery

Introduction

Precommunicating (A1) segment aneurysms of the anterior cerebral artery are rare and often pose technical challenges for coil embolization due to their distinctive configurations. Clinical and radiologic outcomes of treating such aneurysms through endovascular coil embolization are presented herein.

Methods

Data accruing prospectively from May 2002 to August 2013 yielded 48 patients harboring 50 A1 segment aneurysms, each classified as proximal, middle, or distal by location. Clinical outcome of the patients and morphological outcome of the aneurysms were assessed, with emphasis on technical aspects of treatment.

Results

The aneurysms studied occupied either proximal (n?=?39), middle (n?=?6), or distal (n?=?5). Proximal aneurysms were largely directed posteriorly (80 %), and most (97 %) were devoid of branches. Middle and distal aneurysms were associated with the medial lenticulostriate artery, cortical branches, or fenestrations. The preshaped “S” and steam-shaped “S” microcatheters facilitated aneurysm selection in 60 % of lesions. Single-microcatheter technique was most commonly applied for coil embolization (62 %), followed by balloon protection (16 %). Successful aneurysmal occlusion could be achieved in 76 % of the patients, with no procedure-related morbidity and mortality. At final follow-up (mean interval, 29.9 months), stable aneurysmal occlusion was sustained in 93 % of the patients (40/43).

Conclusion

A1 segment aneurysms are amenable to safe and efficacious endovascular coil embolization by adjusting procedural strategy to accommodate distinctive anatomic configurations.     

Mechanical Recanalization Using Solitaire AB Device for Severe Thromboembolic Events in Endovascular Treatment of Intracranial Aneurysms

Introduction

Severe thromboembolism with complete occlusion of the proximal arteries during or after coil embolization can cause serious neurologic deficits. The study aimed to assess the effectiveness and safety of Solitaire AB device as a rescue therapy for severe thromboembolic complications in the endovascular treatment of intracranial aneurysms.

Materials and Methods

Between February 2013 and April 2016, 1047 intracranial aneurysms treated with endovascular procedures were retrospectively reviewed in our center. Severe thromboembolisms occurred in ten patients and were treated by Solitaire AB device including clot retriever and permanent stent deployment.

Results

The location of arterial occlusion was distal to the aneurysm rather than the coil/parent artery interface or in-stent area. Four patients had distal thromboembolic events before coil embolization, and six patients had it after coiling. The complete arterial recanalization (TICI 3) was achieved in all patients, and no cerebral hemorrhage was related to the procedure after the rescue therapy. Among these patients with the aforementioned neurovascular procedures, the mean Glasgow Outcome Scale (GOS) score was 4.5 (ranging 3–5) and eight cases had good outcome with a score of GOS 4–5 at discharge, while eight patients presented mRS ≤2 at 3-month follow-up.

Conclusions

These results demonstrate that mechanical recanalization using Solitaire AB device seems to be effective and safe as a rescue therapy for severe thromboembolic events during cerebral aneurysm embolization.

     

The Stent-Assisted Coil-Jailing Technique Facilitates Efficient Embolization of Tiny Cerebral Aneurysms

Objective

Tiny cerebral aneurysms are difficult to embolize because the aneurysm''s sac is too small for a single small coil, and coils within the aneurysm may escape from the confinement of a stent. This study was performed to introduce the stent-assisted coil-jailing technique and to investigate its effect on the coil embolization of tiny intracranial aneurysms.

Materials and Methods

Sixteen patients with tiny intracranial aneurysms treated with the stent-assisted coil-jailing technique between January 2011 and December 2013 were retrospectively reviewed and followed-up.

Results

All aneurysms were successfully treated with the coil-jailing technique, and at the end of embolization, complete occlusion of the aneurysm was achieved in 9 cases (56.3%), incomplete occlusion in 6 (37.5%), and partial occlusion in 1 (6.3%). Intraprocedural complications included acute thrombosis in one case (6.3%) and re-rupture in another (6.3%). Both complications were managed appropriately with no sequela. Follow-up was performed in all patients for 3-24 months (mean, 7.7 months) after embolization. Complete occlusion was sustained in the 9 aneurysms with initial complete occlusion, progressive thrombosis to complete occlusion occurred in the 6 aneurysms with initial near-complete occlusion, and one aneurysm resulted in progressive thrombosis to complete occlusion after initial partial occlusion. No migration of stents or coils occurred at follow-up as compared with their positions immediately after embolization. At follow-up, all patients had recovered with no sequela.

Conclusion

The stent-assisted coil-jailing technique can be an efficient approach for tiny intracranial aneurysms, even though no definite conclusion regarding its safety can be drawn from the current data.     

Risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair

PURPOSE

We aimed to identify the risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

We retrospectively reviewed contrast-enhanced computed tomography (CT) images of 143 patients who were followed for ≥6 months after EVAR. Sac expansion was defined as an increase in sac diameter of 5 mm relative to the preoperative diameter. Univariate and multivariate analyses were performed to identify associated risk factors for late sac expansion after EVAR from the following variables: age, gender, device, endoleak, antiplatelet therapy, internal iliac artery embolization, and preprocedural variables (aneurysm diameter, proximal neck diameter, proximal neck length, suprarenal neck angulation, and infrarenal neck angulation).

RESULTS

Univariate analysis revealed female gender, endoleak, aneurysm diameter ≥60 mm, suprarenal neck angulation >45°, and infrarenal neck angulation >60° as factors associated with sac expansion. Multivariate analysis revealed endoleak, aneurysm diameter ≥60 mm, and infrarenal neck angulation >60° as independent predictors of sac expansion (P < 0.05, for all).

CONCLUSION

Our results suggest that patients with small abdominal aortic aneurysms (<60 mm) and infrarenal neck angulation ≤60° are more favorable candidates for EVAR. Intraprocedural treatments, such as prophylactic embolization of aortic branches or intrasac embolization, may reduce the risk of sac expansion in patients with larger abdominal aortic aneurysms or greater infrarenal neck angulation.The aim of endovascular abdominal aortic aneurysm repair (EVAR) is to prevent rupture of an abdominal aortic aneurysm (AAA) by depressurizing the aneurysm and excluding it from the systemic circulation using a stent-graft. Aneurysmal sac reduction is a reliable marker for the long-term prognosis after EVAR. Although most aneurysmal sacs shrink after EVAR, some sacs continue to expand. A relationship between aneurysm size and endoleaks was previously reported (1, 2). Most type II endoleaks spontaneously disappear over time, but 10%–25% persist for more than six months after EVAR (3–6). Persistent endoleaks with aneurysmal sac expansion are at high risk of rupture because of the continuously elevated intra-aneurysmal pressure and require a second intervention, such as embolization (7–11). However, it is difficult to predict sac expansion and persistent endoleak before performing EVAR. Although intraoperative intrasac thrombin injection and prophylactic embolization of aortic branches such as the inferior mesenteric artery and lumbar artery are reported to reduce the incidence of type II endoleak, the efficacy and clinical benefit of these procedures in terms of late postoperative aneurysm shrinkage have not been fully evaluated (12–15). Therefore, the purpose of this study was to identify the risk factors associated with late aneurysmal sac expansion after EVAR to determine possible indications for intrasac embolization and prophylactic embolization of aortic branches.     

Efficacy of a Modified Pharmacomechanical Thrombolysis Technique for Endovascular Treatment of Thrombosed Prosthetic Arteriovenous Grafts

Objective

We applied a modified pharmacomechanical thrombolysis (PMT) technique to endovascular treatment of thrombosed arteriovenous (AV) grafts without the use of any mechanical thrombectomy devices. The aim of this study was to evaluate the efficacy of the PMT technique in the treatment of thrombosed AV grafts by analyzing the long-term patency.

Materials and Methods

Eighty-two patients with thrombosed AV grafts were treated with the PMT technique. AV graft surveillance to detect failing/failed access was followed by endovascular treatment.

Results

The technical and clinical success rates were 95% and 95%, respectively. The total number of thrombolysis sessions was 279. A post-intervention primary patency rate was 45% and 22% at 12 and 24 months, respectively. The secondary patency rate was 96% and 91% at 12 and 24 months, respectively. No major complications were noticed.

Conclusion

The modified PMT technique is effective in endovascular treatment of thrombosed AV grafts.     

Time-of-Flight Magnetic Resonance Angiography for Follow-Up of Coil Embolization with Enterprise Stent for Intracranial Aneurysm: Usefulness of Source Images

Objective

The aim of this study was to determine the interobserver and intermodality agreement in the interpretation of time-of-flight (TOF) MR angiography (MRA) for the follow-up of coiled intracranial aneurysms with the Enterprise stent.

Materials and Methods

Two experienced neurointerventionists independently reviewed the follow-up MRA studies of 40 consecutive patients with 44 coiled aneurysms. All aneurysms were treated with assistance from the Enterprise stent and the radiologic follow-up intervals were greater than 6 months after the endovascular therapy. Digital subtraction angiography (DSA) served as the reference standard. The degree of aneurysm occlusion was determined by an evaluation of the maximal intensity projection (MIP) and source images (SI) of the TOF MRA. The capability of the TOF MRA to depict the residual flow within the coiled aneurysms and the stented parent arteries was compared with that of the DSA.

Results

DSA showed stable occlusions in 25 aneurysms, minor recanalization in 8, and major recanalization in 11. Comparisons between the TOF MRA and conventional angiography showed that the MIP plus SI had almost perfect agreement (κ = 0.892, range 0.767 to 1.000) and had better agreement than with the MIP images only (κ = 0.598, range 0.370 to 0.826). In-stent stenosis of more than 33% was observed in 5 cases. Both MIP and SI of the MRA showed poor depiction of in-stent stenosis compared with the DSA.

Conclusion

TOF MRA seemed to be reliable in screening for aneurysm recurrence after coil embolization with Enterprise stent assistance, especially in the evaluation of the SI, in addition to MIP images in the TOF MRA.     

Functional diffusion map as an imaging predictor of functional outcome in patients with primary intracerebral haemorrhage

Objective

Predicting outcome in patients with primary intracerebral haemorrhage (ICH) in the acute stage can provide information to determine the best therapeutic and rehabilitation strategies. We prospectively investigated the predictive value of the functional diffusion map (fDM) in the acute stage of ICH.

Methods

47 patients with ICH were enrolled for clinical evaluation and MRI within 24 h of symptom onset and 5 days after ICH. Functional diffusion mapping prospectively monitored the apparent diffusion coefficient (ADC) maps of perihaematomal oedema. Consequently, the change in perihaematomal oedema was classified into three categories: increased, decreased, or no significant change. Clinical outcomes were evaluated 6 months after ICH according to the modified Rankin Scale. Correlation between clinical outcome and the fDMs was performed.

Results

Among the clinical variables, thalamic haematoma, serum glucose level and National Institutes of Health Stroke Scale scores were significantly different between the good- and poor-outcome groups. The percentage of oedematous tissue undergoing significant change between baseline and Day 5 was also significantly different between the groups.

Conclusion

fDMs allow for spatial voxel-by-voxel tracking of changes in ADC values. It may be feasible to use fDMs to predict the functional outcome of patients with ICH during the acute stage.

Advances in knowledge

The use of fDMs for stroke study is demonstrated. fDMs may be more suitable to reflect the pathophysiological heterogeneity within oedemas and may facilitate another thinking process for imaging study of stroke and other neurological diseases.Primary intracerebral haemorrhage (ICH) is associated with greater mortality and more severe neurological deficits than any other subtype of stroke [1]. Given the emphasis placed on the early introduction of rehabilitation programmes for improving function, prediction of functional outcome in the acute stage of ICH is important. Perihaematomal oedema develops immediately after ICH and peaks several days to weeks later [2,3]. Whether or not perihaematomal oedema contributes to ICH-induced neurological deficits and patient outcome is still controversial and warrants further investigation [4,5]. The pathophysiology of perihaematomal oedema is complicated and may provide valuable clues [4,6]. Diffusion MRI, a technique that can probe tissue microstructure by measuring the diffusion properties of water within tissues, has been used to study perihaematomal injury in patients with ICH, but the results have been inconsistent [7-12].By monitoring changes in the apparent diffusion coefficient (ADC) over time, functional diffusion maps (fDMs) have been developed to monitor regional variations (both increases and decreases) in ADC values in order to provide early stratification of the clinical brain tumour response. Based on the relative change in the ADC value, fDMs can further classify the regions of interest (ROIs) into three categories, which correlate highly with pathological change [13].Given the inconsistent results of previous studies of perihaematomal injury by diffusion-weighted imaging, the diffusion changes within oedematous tissue should be rapid and heterogeneous. In this study, we hypothesised that the early diffusion changes in perihaematomal oedema may correlate with functional outcome in patients with ICH, and that the fDM approach may be a predictive imaging biomarker in the acute stage of ICH.     

Diffusion-Weighted MR Imaging of Intracerebral Hemorrhage

Objective

To document the signal characteristics of intracerebral hemorrhage (ICH) at evolving stages on diffusion-weighted images (DWI) by comparison with conventional MR images.

Materials and Methods

In our retrospective study, 38 patients with ICH underwent a set of imaging sequences that included DWI, T1-and T2-weighted imaging, and fluid-attenuated inversion recovery (FLAIR). In 33 and 10 patients, respectively, conventional and echo-planar T2* gradient-echo images were also obtained. According to the time interval between symptom onset and initial MRI, five stages were categorized: hyperacute (n=6); acute (n=7); early subacute (n=7); late subacute (n=10); and chronic (n=8). We investigated the signal intensity and apparent diffusion coefficient (ADC) of ICH and compared the signal intensities of hematomas at DWI and on conventional MR images.

Results

DWI showed that hematomas were hyperintense at the hyperacute and late subacute stages, and hypointense at the acute, early subacute and chronic stages. Invariably, focal hypointensity was observed within a hyperacute hematoma. At the hyperacute, acute and early subacute stages, hyperintense rims that corresponded with edema surrounding the hematoma were present. The mean ADC ratio was 0.73 at the hyperacute stage, 0.72 at the acute stage, 0.70 at the early subacute stage, 0.72 at the late subacute stage, and 2.56 at the chronic stage.

Conclusion

DWI showed that the signal intensity of an ICH may be related to both its ADC value and the magnetic susceptibility effect. In patients with acute stroke, an understanding of the characteristic features of ICH seen at DWI can be helpful in both the characterization of intracranial hemorrhagic lesions and the differentiation of hemorrhage from ischemia.     

Long-term results of microcoil embolization for colonic haemorrhage: how common is rebleeding?

Objective:

To determine the long-term results of patients undergoing transcatheter coil embolization for the treatment of acute colonic haemorrhage.

Methods:

Patients undergoing angiography for suspected colonic bleeding between January 2002 and December 2012 were reviewed (average age, 60 years; 38.4% male). Baseline, procedural and outcome parameters were recorded following the Society of Interventional Radiology guidelines. Primary outcome measures included early (<30 days) and delayed (>30 days) rebleeding events and adverse procedure-related complication. Average follow-up time was 996 days (median, 232 days; range, 30–3663 days).

Results:

One or multiple sites of bleeding were identified in 40 cases. Coil embolization was performed in 39 patients, 26 (66.7%, 26/39) of whom were treated successfully without technical/clinical failure (n = 12) or loss to follow-up (n = 1). Three patients (11.5%, 3/26) rebled in the early period within 30 days; one patient went on to hemicolectomy. Four patients (15.3%, 4/26) experienced delayed rebleeding after 30 days; two of whom also underwent hemicolectomy. No major complication occurred. One minor complication of short segment arterial dissection was seen in the clinical failure group. One case of asymptomatic ischaemia was identified on a patient undergoing pre-operative colonoscopy for elective bowel resection. No instances of ischaemic stricture were seen. All-cause mortality of successfully treated and all patients at 1 year was 31% (8/26) and 30% (12/40), respectively.

Conclusion:

Transcatheter coil embolization is a durable treatment option with a technical and clinical success rate of 67% in the setting of acute colonic haemorrhage. A modest level of rebleeding was seen among successfully treated patients in both the early and delayed periods; in the majority of patients, embolization proved to be definitive therapy.

Advances in knowledge:

Transcatheter coil embolization is a durable and potentially definitive therapy in the management of acute colonic haemorrhage.Acute lower gastrointestinal (GI) bleeding, defined by bleeding distal to the ligament of Treitz, is a potentially life-threatening condition that is often treated conservatively by medical management alone. Colonic haemorrhage constitutes the predominant subset of lower GI bleeding cases, occurring in up to 75–90% of patients and is commonly owing to bleeding diverticula, angiodysplasia, inflammatory bowel disease or neoplasm.¹ In up to 20% of these patients, haemorrhage is classified as massive, requiring blood transfusions greater than 3–5 units of packed red blood cells (RBCs) to maintain haemodynamic stability.² In these instances, more invasive management for haemostasis is necessary, with treatment options including endoscopic therapy (i.e. colonoscopy), transcatheter embolization and/or surgery.In the past two decades, suboptimal performance of alternative endovascular techniques such as vasopressin infusion and continued developments in coaxial catheter technique for transcatheter coil embolization have resulted in its increased usage by demonstrating an increased effectiveness at controlling life-threatening bleeding from a minimally invasive approach.^3,4 Despite these advances, few studies to date have evaluated the long-term efficacy of superselective transcatheter microcoil embolization in the treatment of colonic haemorrhage. Given that embolization treats a symptom (i.e. bleeding in a patient with diverticulosis) of an underlying problem rather than the problem itself, recurrence is a concern. The purpose of this study is to retrospectively review all transcatheter microcoil embolizations undertaken at our institution for acute colonic bleeding to determine the short-term clinical outcome and long-term durability of this treatment.