Stent-assisted embolization of recurrent or residual intracranial aneurysms.

INTRODUCTION: Intracranial stents have theoretical advantages in the treatment of wide-necked intracranial aneurysms, but the usability of intracranial stents in the retreatment of recurrent intracranial aneurysms is relatively unknown. In this study, we aim to evaluate the safety and efficacy of stent-assisted embolization in the retreatment of recurrent or residual intracranial aneurysms. METHODS: Retrospective evaluation was carried out for 55 consecutive patients (17 men and 38 women; mean age 51.5 years), with 56 recurrent or residual intracranial aneurysms electively retreated with stent-assisted embolization. RESULTS: The technical success rate was 91% (50/55 patients). Procedural complications were encountered with six patients (11%). Angiographic and clinical follow-up data were available for 51 patients (93%), with a mean follow-up period of 28.1 months. No rebleedings were encountered during the study period. The clinical outcome was favorable in 50 patients (91%), with a Glasgow Outcome Score of 4 (N = 14) or 5 (N = 36) at the end of the study period. Poor clinical outcome correlated with very large (>2 cm) total aneurysm size (P = 0.002), large (>10 mm) recurrent aneurysm size (P = 0.011), and occurrence of periprocedural complications (P < 0.001). CONCLUSION: Stent-assisted coil embolization is beneficial for the retreatment of wide-necked recurrent or residual intracranial aneurysms, but stability and permanent occlusion of the recurrent aneurysm is unlikely if the aneurysm exceeds 2 cm in diameter, the recurrent diameter of the aneurysm exceeds 10 mm, or if mass effect is present with the recurrent aneurysm.

The silk flow-diverting stent in the endovascular treatment of complex intracranial aneurysms: technical aspects and midterm results in 24 consecutive patients.

BACKGROUND: The flow-diverting stent is a new option in endovascular therapy specifically designed for the endovascular reconstruction of a segmentally diseased artery. The safety of flow-diverting stents is still equivocal. OBJECTIVE: To evaluate the technical aspects, thromboembolic events, adjunctive therapies, and midterm results in patients with complex intracranial aneurysms treated with a flow-diverting stent (Silk; Balt Extrusion, Montmorency, France). METHODS: We retrospectively examined angiographic images and clinical reports of 24 consecutive patients (29 stents) treated (n = 23) or attempted to treat (n = 1) with a flow-diverting device in 2 Finnish centers between March 2009 and October 2010. RESULTS: The primary technical success rate was 67% (16/24). Adjunctive therapies were required in 6 (25%) patients, including 4 cases where intra-arterial abciximab was administered for the treatment of intraprocedural thromboembolic events. Technique-related complication rate and the 30-day mortality rate were each 4% (1/24). Follow-up imaging revealed 1 case of delayed in-stent thrombosis resulting in permanent disability of the patient, 1 asymptomatic occlusion, and 1 asymptomatic stenosis of the stented artery. Complete occlusion of the aneurysm with fully patent parent artery was observed in 16 of the 23 aneurysms (70%) where follow-up images were available. CONCLUSION: Many previously untreatable cerebral aneurysms may be successfully treated with the Silk flow-diverting stent, but the associated risk of thromboembolic events is justifiable only if conventional endovascular or surgical treatment options are not applicable. Perioperative thromboembolic events should be prepared for and treated without unnecessary delays because they frequently respond to adjunctive medical therapy.

Wide-necked intracranial aneurysms: treatment with stent-assisted coil embolization during acute (<72 hours) subarachnoid hemorrhage--experience in 61 consecutive patients.

PURPOSE: To evaluate the safety and efficacy of stent-assisted embolization of ruptured wide-necked intracranial aneurysms during acute subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: Institutional review board approval for this retrospective study was obtained; the need to obtain informed consent was waived. Results in 61 consecutive patients (20 men, 41 women; mean age, 55.1 years; range, 26-83 years) with acutely ruptured wide-necked intracranial aneurysms who were treated with stent-assisted coil embolization were evaluated. The mean length of angiographic follow-up was 12.1 months (range, 0-52 months). Statistical analysis was performed to determine whether the features of the patient and the ruptured aneurysm affected the primary angiographic result or the patient's clinical outcome. Categoric and dichotomous variables were examined with the chi(2) test or the Fisher exact test; the Mann-Whitney U test and Kruskal-Wallis one-way analysis were used to compare continuous-scale data for non-normally distributed variables. RESULTS: The technical success rate was 72% (44 of 61). The technique-related complication rate was 21% (13 of 61), and the 30-day mortality rate was 20% (12 of 61). There was only one case of rebleeding, and clinical outcome was good for the majority of the patients (69% [42 of 61] had Glasgow Outcome Scale scores of 4 or 5 at the end of the study period). CONCLUSION: Stent-assisted coil embolization is a feasible method for the endovascular treatment of wide-necked intracranial aneurysms that are difficult to treat surgically or with balloon-assisted embolization during acute SAH. The risk of subsequent rerupture of the aneurysm seems to be reduced for aneurysms treated early compared with that for nonsecured aneurysms.

Perfusion differences on SPECT and PWI in patients with acute ischemic stroke.

INTRODUCTION: The purposes of the present study were to compare the flow defect volumes on perfusion-weighted magnetic resonance imaging (PWI) and (99m)Tc-labeled ethylcysteinate dimer ((99m)Tc-ECD) single photon emission computed tomography (SPECT) at acute and subacute stages of ischemic stroke and to analyze the relationship between the detected flow defects on the two methods and neurological status and clinical outcomes. METHODS: Perfusion defects on PWI and SPECT were measured within 48 h and on day 8 of the onset of stroke from 22 patients with their first-ever acute supratentorial ischemic stroke. The primary neurological status was evaluated prior to the imaging. Clinical outcome was assessed at 3 months after the onset of the stroke. RESULTS: The volumes of cerebral blood flow (CBF) defects did not differ between SPECT and PWI within the 48-h examinations. However, the volume of CBF defect was significantly larger on SPECT than on PWI on day 8 (p = 0.03). Within the 48-h examinations, the CBF defect volumes on SPECT and PWI were comparably related to the neurological status. On day 8, the CBF defect volume on SPECT showed higher correlation to the neurological status and more precisely predicted the clinical outcomes at 3 months than PWI. CONCLUSIONS: (99m)TC-ECD-SPECT and PWI both have ability to detect cerebral hypoperfusion in patients with ischemic stroke but with some differences. The value of SPECT is more accurate in terms of the delayed outcome, such as prognosis and rehabilitation planning.

Discriminating accuracy of medial temporal lobe volumetry and fMRI in mild cognitive impairment.

We investigated structural and functional changes in the medial temporal lobe (MTL) using magnetic resonance imaging (MRI) and compared the discriminative power of these measures with neuropsychological testing in mild cognitive impairment (MCI) and Alzheimer's disease (AD). Functional MRI (fMRI) was performed in 21 elderly controls, 14 MCI subjects, and 15 mild AD patients during encoding and cued retrieval of word-picture pairs. A region-of-interest-based approach in SPM2 was used to extract the extent of hippocampal activation. The volumes of the hippocampus and entorhinal cortex (EC) were manually outlined from anatomical MR images. Discriminant analyses were conducted to assess the ability of hippocampal fMRI, MTL volumetry, and neuropsychological measures to classify subjects into clinical groups. Entorhinal but not hippocampal volumes differed significantly between the control and MCI subjects. Both entorhinal and hippocampal volumes differed between MCI and AD patients. There were no significant differences in the extent of hippocampal fMRI activation during encoding or retrieval between the groups. Entorhinal volume was the best discriminator with a discriminating accuracy of 85.7% between controls and MCI, 86.2% between MCI and AD, and 97.2% between controls and AD. Delayed recall of a wordlist classified the subjects, second best, with a discriminating accuracy of 81.8% between controls and MCI, 75% between MCI and AD and 93.5% between controls and AD. The accuracy of hippocampal volumetry ranged from 42.9 to 69.4%, and hippocampal fMRI activation during encoding and retrieval had a classification accuracy of only 41.4-57.7% between the groups. Our results suggest that evaluation of entorhinal atrophy, in addition to the prevailing diagnostic criteria, seems promising in the identification of prodromal AD. Future technical improvements may improve the utilization of hippocampal fMRI for early diagnostic purposes.

Differential hypometabolism patterns according to mild cognitive impairment subtypes.

AIMS: The present study investigated cerebral glucose metabolism and structural atrophy in controls and subjects with mild cognitive impairment (MCI). METHODS: The study included 13 controls, 7 MCI subjects considered as prodromal Alzheimer's disease (MCI of the Alzheimer type, aMCI) and 7 MCI subjects having cognitive decline due to other causes, established by clinical evaluation (MCI of the non-Alzheimer type, naMCI). Glucose metabolism in the frontal, parietal and posterior cingulate cortices, the hippocampus and parahippocampal gyrus was evaluated using Statistical Parametric Mapping 2 (SPM2). Structural analysis of the whole-brain grey matter was performed with voxel-based morphometry in SPM2. RESULTS: Significant hypometabolism was found in the medial temporal lobe in aMCI subjects compared to the controls and naMCI subjects. In addition, both the aMCI and naMCI patients had hypometabolism of the posterior cingulum relative to controls. The naMCI subjects showed atrophy of frontal and occipital areas compared to controls and aMCI patients, whereas the aMCI subjects did not show atrophy compared to the other groups. CONCLUSION: aMCI subjects have reduced glucose uptake levels, particularly in areas susceptible to pathological changes in Alzheimer's disease, and the changes are more pronounced in aMCI than naMCI subjects. Our results also suggest that functional changes may be more prominent than structural changes in MCI.

Stent-assisted coil embolization of wide-necked renal artery bifurcation aneurysms.

PURPOSE: To report preliminary results of stent-assisted coil embolization in the treatment of wide-necked renal artery bifurcation aneurysms. MATERIALS AND METHODS: Four patients (three women, one man; mean age, 54 years; range, 49-67 y) with wide-necked renal artery aneurysms were treated with dedicated neurointerventional self-expanding nitinol stent-assisted coil embolization during a 2-year period. The stent was delivered over the neck of the aneurysm, after which the aneurysm was filled with detachable coils through a microcatheter placed into the aneurysm through the stent mesh. RESULTS: Stent delivery and coil embolization was successfully completed in all cases. Complete aneurysm occlusion without coil protrusion or arterial flow compromise was obtained in all patients. A small peripheral subsegmental renal infarction necessitating no therapy was registered in one patient on postembolization computed tomography. At follow-up angiography 1 year after embolization, no aneurysm recanalization or arterial obstruction was registered. CONCLUSIONS: Our preliminary experience indicates that stent-assisted coil embolization is technically feasible and effective for the exclusion of challenging renal artery bifurcation aneurysms without the sacrifice of any branch arteries.

Crossed cerebellar diaschisis in acute ischemic stroke: a study with serial SPECT and MRI.

This study evaluated the relationship between crossed cerebellar diaschisis (CCD) and (1) lesion volume and location in the acute phase and 1 week after stroke onset and (2) clinical outcome. Twenty-two patients with cerebral ischemic stroke underwent single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI) within 48 h and on day 8 from onset. Interhemispheric asymmetric indices (AI) on SPECT were calculated for medial, intermediate, and lateral zones of the cerebellum. Lesion volumes and locations were obtained from diffusion-weighted MRI. Neurological status and 3-month clinical outcome were evaluated. Within 48 h, lesion locations in the temporal association cortex and pyramidal tract of the corona radiata were independent determinants for the AI of the medial zone (R(2)=0.439). Lesion locations in the primary, premotor, and supplementary motor cortices, primary somatosensory cortex, and anterior part of the posterior limb of the internal capsule were determinants for the AI of the intermediate zone (R(2)=0.785). Lesions in the primary motor cortex, premotor, and supplementary motor cortices and in the genu of the internal capsule were determinants for the AI of the lateral zone (R(2)=0.746). On day 8, the associations were decreased. The AIs of the intermediate and lateral zones and lesion location in the parietal association cortex were independently associated with the 3-month clinical outcome (R(2)>0.555). Acute CCD is a result of functional deafference, while in the subacute phase, transneuronal degeneration might contribute to CCD. CCD in the intermediate and later zones is a better indicator than that in the medial zone.

Onyx, a new liquid embolic material for peripheral interventions: preliminary experience in aneurysm, pseudoaneurysm, and pulmonary arteriovenous malformation embolization.

PURPOSE: To describe our preliminary experience with a new liquid embolization agent, Onyx, in peripheral interventions. METHODS AND RESULTS: We successfully treated two peripheral aneurysms (one in an internal iliac artery, one in a thoracic collateral artery of an aortic coarctation), two peripheral pseudoaneurysms (one in a lumbar artery, one in a renal artery), and one pulmonary arteriovenous malformation. CONCLUSION: Onyx is a promising alternative embolic material for peripheral interventions. It can be combined with coils in selected cases, and balloon catheters can be effectively used during slow injection of embolic material to control flow and protect the aneurysm neck.

Increased fMRI responses during encoding in mild cognitive impairment.

Structural and functional magnetic resonance imaging (fMRI) was performed on 21 healthy elderly controls, 14 subjects with mild cognitive impairment (MCI) and 15 patients with mild Alzheimer's disease (AD) to investigate changes in fMRI activation in relation to underlying structural atrophy. The fMRI paradigm consisted of associative encoding of novel picture-word pairs. Structural analysis of the brain was performed using voxel-based morphometry (VBM) and hippocampal volumetry. Compared to controls, the MCI subjects exhibited increased fMRI responses in the posterior hippocampal, parahippocampal and fusiform regions, while VBM revealed more atrophy in MCI in the anterior parts of the left hippocampus. Furthermore, the hippocampal volume and parahippocampal activation were negatively correlated in MCI, but not in controls or in AD. We suggest that the increased fMRI activation in MCI in the posterior medial temporal and closely connected fusiform regions is compensatory due to the incipient atrophy in the anterior medial temporal lobe.

Subarachnoid hemorrhage in the subacute stage: elevated apparent diffusion coefficient in normal-appearing brain tissue after treatment.

PURPOSE: To prospectively evaluate whether subarachnoid hemorrhage (SAH) is associated with a change in the apparent diffusion coefficient (ADC) in normal-appearing brain parenchyma. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained for all patient and volunteer studies. One hundred patients (48 men, 52 women; mean age, 52 years +/- 12 [standard deviation]) with aneurysmal SAH underwent conventional and diffusion-weighted magnetic resonance (MR) imaging at a mean of 9 days +/- 3 after SAH to evaluate possible lesions caused by SAH, treatment of SAH, and vasospasm. Aneurysms were treated surgically (n = 70) or endovascularly (n = 30) before MR imaging. Diffusion-weighted MR imaging was performed at 1-year follow-up in 30 patients (10 men, 20 women; mean age, 51 years +/- 11). Thirty healthy age-matched volunteers (11 men, 19 women; mean age, 54 years +/- 16) underwent MR imaging with an identical protocol. ADC values were measured bilaterally in the gray and white matter (parietal, frontal, temporal, occipital lobes; cerebellum; caudate nucleus; lentiform nucleus; thalamus; and pons) that appeared normal on T2-weighted and diffusion-weighted MR images. Linear mixed model was used for comparison of ADC values of supratentorial gray matter and white matter; general linear regression analysis was used for comparison of ADC values of cerebellum and pons. RESULTS: In patients with SAH, the ADC values in normal-appearing white matter, with a single exception in the frontal lobe (P = .091), were significantly higher than they were in healthy volunteers (P /= .121). CONCLUSION: SAH and its treatment may cause global mild vasogenic edema in white matter and deep gray matter that is undetectable on T2-weighted and diffusion-weighted MR images but is detectable by measuring the ADC value in the subacute stage of SAH.

Acute ischemic stroke: predictive value of 2D phase-contrast MR angiography--serial study with combined diffusion and perfusion MR imaging.

PURPOSE: To evaluate phase-contrast magnetic resonance (MR) angiography and diffusion- and perfusion-weighted imaging in predicting evolution of infarction and clinical outcome. MATERIALS AND METHODS: Phase-contrast angiographic and diffusion-weighted images obtained 1 and 2 days after acute middle cerebral artery (MCA) stroke were assessed in 43 patients; 39 underwent perfusion-weighted imaging on day 1. Follow-up phase-contrast angiographic and T2-weighted images (n = 38) were obtained on day 8. Clinical outcome was assessed at 3 months. Patients were assigned to three groups according to angiographic findings on day 1: group 1, absence of flow in proximal MCA (M1 segment); group 2, internal carotid artery (ICA) occlusion with collateral M1 flow; group 3, flow in ICA and M1. Differences in lesion volumes on diffusion- and perfusion-weighted maps among groups were compared with one-way analysis of variance with Tukey post hoc multiple comparisons. RESULTS: Patients in group 1 had significantly larger infarct growth, volumes of hypoperfusion on relative cerebral blood volume (rCBV) and relative cerebral blood flow maps, and initial and final infarct volumes than did other patients (P <.05). Initial perfusion deficits on mean transit time maps were significantly (P =.002) larger in group 2 than in group 3, but there were no significant differences in infarct growth (P =.977), final infarct volume on day 8 (P =.947), and clinical outcome (P =.969). Absence of M1 flow on day 1 was significantly associated with unfavorable clinical outcome (modified Rankin score > or = 3) at 3 months (P =.010, chi(2) test). Discriminant analysis revealed that rCBV maps alone and combination of diffusion-weighted imaging and MR angiography yielded the highest accuracy in predicting an unfavorable clinical outcome. CONCLUSION: Phase-contrast MR angiography can provide complementary information to that with diffusion- and perfusion- weighted imaging in predicting the outcome of patients with acute stroke.

Carotid artery stenosis: reproducibility of automated 3D CT angiography analysis method.

The aim of this study was to assess the reproducibility and anatomical accuracy of automated 3D CT angiography analysis software in the evaluation of carotid artery stenosis with reference to rotational DSA (rDSA). Seventy-two vessels in 36 patients with symptomatic carotid stenosis were evaluated by 3D CT angiography and conventional DSA (cDSA). Thirty-one patients also underwent rotational 3D DSA (rDSA). Multislice CT was performed with bolus tracking and slice thickness of 1.5 mm (1-mm collimation, table feed 5 mm/s) and reconstruction interval of 1.0 mm. Two observers independently performed the stenosis measurements on 3D CTA and on MPR rDSA according to the NASCET criteria. The first measurements on CTA utilized an analysis program with automatic stenosis recognition and quantitation. In the subsequent measurements, manual corrections were applied when necessary. Interfering factors for stenosis quantitation, such as calcifications, ulcerations, and adjacent vessels, were registered. Intraobserver and interobserver correlation for CTA were 0.89 and 0.90, respectively (p<0.001). The interobserver correlation between two observers for MPR rDSA was 0.90 (p<0.001). The intertechnique correlation between CTA and rDSA was 0.69 (p<0.001) using automated measurements but increased to 0.81 (p<0.001) with the manually corrected measurements. Automated stenosis recognition achieved a markedly poorer correlation with MPR rDSA in carotids with interfering factors than those in cases where there were no such factors. Automated 3D CT angiography analysis methods are highly reproducible. Manually corrected measurements facilitated avoidance of the interfering factors, such as ulcerations, calcifications, and adjacent vessels, and thus increased anatomical accuracy of arterial delineation by automated CT angiography with reference to MPR rDSA.

Apolipoprotein E polymorphism and acute ischemic stroke: a diffusion- and perfusion-weighted magnetic resonance imaging study.

Diffusion- and perfusion-weighted magnetic resonance imaging (MRI) was used to study the putative effects of apolipoprotein E (ApoE) polymorphism in stroke. Thirty-one patients with acute stroke, comparative for age and gender were scanned, nine of whom were ApoE allele epsilon 4 carriers. Initially, less than 24 hours from the onset of stroke, the epsilon 4 carriers had significantly smaller volumes of hypoperfusion on relative cerebral blood volume map (P = 0.001), and smaller infarct volumes (P = 0.008) compared with the noncarriers. By day 8, this difference in the infarct volumes had disappeared, suggesting relatively enhanced infarct growth. On average, the total infarct volume increased 145% of the initial infarct volume in the epsilon 4 carriers, and 84% in the noncarriers. There were strong correlations between the imaging findings and clinical status initially and with the outcome 3 months after the stroke in the epsilon 4 noncarriers, but, with a single exception at acute phase, a lack thereof in the epsilon 4 carriers. These patterns were virtually similar in a subgroup of patients with middle cerebral artery stroke. These data support the hypothesis of increased general vulnerability of the brain in the epsilon 4 carriers. Thus, the effects of ApoE polymorphism should be accounted for when interpreting diffusion- and perfusion-weighted MRI studies, particularly if predicting lesion growth.

Patients with acute flank pain: comparison of MR urography with unenhanced helical CT.

PURPOSE: To compare unenhanced helical computed tomography (CT) and magnetic resonance (MR) urography, by using T2-weighted and contrast material-enhanced T1-weighted imaging to examine patients with acute flank pain, with reference to excretory urography and final clinical diagnosis. MATERIALS AND METHODS: Forty-nine patients underwent CT, MR urography (with T2-weighted and gadopentetate dimeglumine-enhanced T1-weighted sequences), and excretory urography. CT and MR urographic findings were evaluated separately and independently by two radiologists each (CT, observers A and B; MR urography, observers C and D) for the presence, cause, level, and degree of obstruction. The final conclusive diagnosis was based on the combination of excretory urographic, clinical, and interventional results. RESULTS: At final diagnosis, 32 (65%) patients were found to have ureteral stones causing unilateral obstruction. In ureteral stone detection, the sensitivity and specificity of CT were 90.6% (29 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer A) and 90.6% (29 of 32 patients) and 94.1% (16 of 17 patients), respectively (observer B), while those of MR urography were 93.8% (30 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer C) and 100.0% (32 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer D). Spearman correlation coefficients for stone size at CT were 0.76 (P <.001) and 0.75 (P <.001) and at MR urography, 0.49 (P =.005) and 0.51 (P =.004). CONCLUSION: In routine clinical practice, CT is the modality of choice in the evaluation of patients with acute flank pain. MR urography is an accurate and suitable alternative imaging technique in selected patients.