Should posterior cerebral artery occlusions be recanalized? Insights from the Trevo Registry.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the safety and effectiveness of mechanical thrombectomy (MT) in patients with acute ischaemic stroke related to isolated and primary posterior cerebral artery (PCA) occlusions amongst the patients enrolled in the multicentre post-market Trevo Registry. METHOD: Amongst the 2008 patients enrolled in the Trevo Registry with acute ischaemic stroke due to large vessel occlusion treated by MT, 22 patients (1.1%) [10 females (45.5%), mean age 66.2 ± 14.3 years (range 28-91)] had a PCA occlusion [17 P1 (77.3%) and five P2 occlusions (22.7%)]. Recanalization after the first Trevo (Stryker, Fremont, CA, USA) pass and at the end of the procedure was rated using the modified Thrombolysis in Cerebral Infarction (mTICI) score. Procedure-related complications (i.e. groin puncture complication, perforation, symptomatic haemorrhage, embolus in a new territory) were also recorded. The modified Rankin Scale at 90 days was assessed. RESULTS: Median National Institutes of Health Stroke Scale at admission was 14 (interquartile range 8-16). Stroke aetiology was cardio-embolic in 68.2% of cases. Half of the patients (11/22) received intravenous tissue plasminogen activator. 54.5% of the patients were treated under general anaesthesia. Reperfusion (i.e. mTICI 2b or 3) after first pass was obtained in 65% of cases. Final mTICI 2b-3 reperfusion was obtained in all cases. Only one (4.5%) procedure-related complication was recorded (puncture site) that resolved after surgery. At 90-day follow-up, modified Rankin Scale 0-2 was obtained in 59% of the patients and 9.1% died within the first 3 months after MT. CONCLUSION: Mechanical thrombectomy for PCA occlusions seems to be safe (<5% procedure-related complications) and effective. Larger repository datasets are needed.

SOLITAIRE™ with the intention for thrombectomy (SWIFT) trial: design of a randomized, controlled, multicenter study comparing the SOLITAIRE™ Flow Restoration device and the MERCI Retriever in acute ischaemic stroke.

RATIONALE: Self-expanding stent retrievers are a promising new device class designed for rapid flow restoration in acute cerebral ischaemia. The SOLITAIRE™ Flow Restoration device (SOLITAIRE) has shown high rates of recanalization in preclinical models and in uncontrolled clinical series. AIMS: (1) To demonstrate non-inferiority of SOLITAIRE compared with a legally marketed device, the MERCI Retrieval System®; (2) To demonstrate safety, feasibility, and efficacy of SOLITAIRE in subjects requiring mechanical thrombectomy diagnosed with acute ischaemic stroke. DESIGN : Multicenter, randomized, prospective, controlled trial with blinded primary end-point ascertainment. STUDY PROCEDURES: Key entry criteria include: age 22-85; National Institute of Health Stroke Scale (NIHSS) ≥8 and <30; clinical and imaging findings consistent with acute ischaemic stroke; patient ineligible or failed intravenous tissue plasminogen activator; accessible occlusion in M1 or M2 middle cerebral artery, internal carotid artery, basilar artery, or vertebral artery; and patient able to be treated within 8 h of onset. Sites first participate in a roll-in phase, treating two patients with the SOLITAIRE device, before proceeding to the randomized phase. In patients unresponsive to the initially assigned therapy, after the angiographic component of the primary end-point is ascertained (reperfusion with the initial assigned device), rescue therapy with other reperfusion techniques is permitted. OUTCOMES: The primary efficacy end-point is successful recanalization with the assigned study device (no use of rescue therapy) and with no symptomatic intracranial haemorrhage. Successful recanalization is defined as achieving Thrombolysis In Myocardial Ischemia 2 or 3 flow in all treatable vessels. The primary safety end-point is the incidence of device-related and procedure-related serious adverse events. A major secondary efficacy end-point is time to achieve initial recanalization. Additional secondary end-points include clinical outcomes at 90 days and radiologic haemorrhagic transformation.

Endovascular mechanical thrombectomy for the treatment of acute ischemic stroke due to arterial dissection.

Arterial dissections account for 2% of strokes in all age groups, and up to 25% in patients aged 45 years or younger. The safety of endovascular intervention in this patient population is not well characterized. We identified all patients in the Merci registry - a prospective, multi-center post-market database enrolling patients treated with the Merci Retriever thrombectomy device - with arterial dissection as the most likely stroke etiology. Stroke presentation and procedural details were obtained prospectively; data regarding procedural complications, intracerebral hemorrhage (ICH), and the use of stenting of the dissected artery were obtained retrospectively. Of 980 patients in the registry, ten were identified with arterial dissection (8/10 ICA; 2/10 vertebrobasilar). The median age was 48 years with a baseline NIH stroke scale score of 16 and median time to treatment of 4.9 h. The procedure resulted in thrombolysis in cerebral ischemia (TICI) scores of 2a or better in eight out of ten and TICI 2b or better in six out of ten patients. Stenting of the dissection was performed in four of nine (44%). The single complication (1/9; 11%) - extension of a dissected carotid artery - was treated effectively with stenting. No symptomatic ICH or stroke in a previously unaffected territory occurred. A favorable functional outcome was observed in eight out of ten patients. Despite severe strokes on presentation, high rates of recanalization (8/10) and favorable functional outcomes (8/10) were observed. These results suggest that mechanical thrombectomy in patients with acute stroke resulting from arterial dissection is feasible, safe, and may be associated with favorable functional outcomes.

Frequency and clinical context of decreased apparent diffusion coefficient reversal in the human brain.

PURPOSE: To determine the probability that regions of decreased apparent diffusion coefficient (ADC) return to normal without persistent symptoms or T2 change and the settings in which these ADC reversals occur. MATERIALS AND METHODS: Three hundred magnetic resonance (MR) imaging studies were selected at random from a database of 7,147 examinations to determine the probability of a pathologically decreased ADC. In cases with decreased ADC, the clinical history was recorded and, if available, follow-up MR imaging findings were evaluated. Five cases of ADC reversal became known during the same period and were evaluated to determine the initial ADC decrease, clinical outcome, and findings at follow-up imaging. RESULTS: Findings in 116 of 300 MR imaging studies revealed regions of decreased ADC. In 49 of 116 studies, follow-up MR imaging examinations were performed at least 4 weeks after the onset of symptoms; ADC did not reverse. Five cases of ADC reversal were identified in the same period, giving an estimated 0.2%-0.4% probability of ADC reversal. Clinical settings were venous sinus thrombosis and seizure (n = 3), hemiplegic migraine (n = 1), and hyperacute arterial infarction (n = 1). Both white matter (n = 3) and gray matter (n = 3) regions were involved. CONCLUSION: Reversal of ADC lesions is rare, occurs in complicated clinical settings, and can involve white or gray matter.

Utility of perfusion-weighted CT imaging in acute middle cerebral artery stroke treated with intra-arterial thrombolysis: prediction of final infarct volume and clinical outcome.

BACKGROUND AND PURPOSE: The goal of this study was to evaluate the utility of perfusion-weighted CT (PWCT) in predicting final infarct volume and clinical outcome in patients with acute middle cerebral artery (MCA) stroke. METHODS: Twenty-two consecutive patients with MCA stem occlusion who underwent intra-arterial thrombolysis within 6 hours of stroke onset had noncontrast CT and CT angiography with whole-brain PWCT imaging before treatment. Infarct volumes were computed from the initial PWCT and follow-up scans; clinical outcome was measured with the modified Rankin scale. RESULTS: Initial PWCT lesion volumes correlated significantly with final infarct volume (P=0.0002) and clinical outcome (P=0.01). For the 10 patients with complete recanalization, the relationship between initial and final lesion volume was especially strong (R(2)=0.94, P<0.0001, slope of regression line=0.92). For those without complete recanalization, there was progression of lesion volume on follow-up imaging (R(2)=0.50, P=0.01, slope of regression line=1.61). All patients with either initial PWCT lesion volumes >100 mL or no recanalization had poor outcomes (Rankin scores, 4 to 6). Mean admission NIH Stroke Scale scores and mean lesion volumes in the poor outcome group were significantly different compared with the good or fair outcome (Rankin scores, 0 to 3) group (21+/-4 versus 17+/-5, P=0.05, and 106+/-79 versus 29+/-37 mL, P=0.01). Patients with initial volumes <100 mL and partial or complete recanalization all had good (Rankin scores, 0 to 2) or fair (Rankin score, 3) outcomes. CONCLUSIONS: Lesion volumes on admission PWCT images approximate final infarct volume for patients with early complete recanalization of MCA stem occlusion. For those without complete recanalization, there is subsequent enlargement of lesion volume on follow-up. Initial PWCT lesion volumes also have predictive value; volumes >100 mL are associated with a poor clinical outcome. In these highly selected patients, initial PWCT lesion volume was a stronger predictor of clinical outcome than was initial NIH Stroke Scale score.

CT angiography in the rapid triage of patients with hyperacute stroke to intraarterial thrombolysis: accuracy in the detection of large vessel thrombus.

PURPOSE: The purpose of this work was to evaluate the accuracy of CT angiography (CTA) for the detection of large vessel intracranial thrombus in clinically suspected hyperacute (<6 h) stroke patients. METHOD: Forty-four consecutive intraarterial thrombolysis candidates underwent noncontrast CT followed immediately by CTA. Axial source and two-dimensional collapsed maximum intensity projection reformatted CTA images were rated for the presence or absence of large vessel occlusion. Five hundred seventy-two circle-of-Willis vessels were reviewed; arteriographic correlation was available for 224 of these. RESULTS: Sensitivity and specificity for the detection of large vessel occlusion were 98.4 and 98.1%; accuracy, calculated using receiver operating characteristic analysis, was 99%. Mean time for acquisition, reconstruction, and analysis of CTA images was approximately 15 min. CONCLUSION: CTA is highly accurate for the detection and exclusion of large vessel intracranial occlusion and may therefore be valuable in the rapid triage of hyperacute stroke patients to intraarterial thrombolytic treatment.

Combined surgical and endovascular techniques of flow alteration to treat fusiform and complex wide-necked intracranial aneurysms that are unsuitable for clipping or coil embolization.

OBJECT: Certain intracranial aneurysms, because of their fusiform or complex wide-necked structure, giant size, or involvement with critical perforating or branch vessels. are unamenable to direct surgical clipping or endovascular coil treatment. Management of such lesions requires alternative or novel treatment strategies. Proximal and distal occlusion (trapping) is the most effective strategy. In lesions that cannot be trapped, alteration in blood flow to the "inflow zone," the site most vulnerable to aneurysm growth and rupture, is used. METHODS: From 1991 to 1999 the combined neurosurgical-neuroendovascular team at the Massachusetts General Hospital (MGH) managed 48 intracranial aneurysms that could not be clipped or occluded. Intracavernous internal carotid artery aneurysms were excluded from this analysis. By applying a previously described aneurysm rupture risk classification system (MGH Grades 0-5) based on the age of the patient, aneurysm size, Hunt and Hess grade, Fisher grade, and whether the aneurysm was a giant lesion located in the posterior circulation, the authors found that a significant number of patients were at moderate risk (MGH Grade 2; 31.3% of patients) and at high risk (MGH Grades 3 or 4; 22.9%) for treatment-related morbidity. The lesions were treated using a variety of strategies--surgical, endovascular, or a combination of modalities. Aneurysms that could not be trapped or occluded were treated using a paradigm of flow alteration, with flow redirected from either native collateral networks or from a surgically performed vascular bypass. Overall clinical outcomes were determined using the Glasgow Outcome Scale (GOS). A GOS score of 5 or 4 was achieved in 77.1%, a GOS score of 3 or 2 in 8.3%, and death (GOS 1) occurred in 14.6% of the patients. Procedure-related complications occurred in 27.1% of cases; the major morbidity rate was 6.3% and the mortality rate was 10.4%. Three patients experienced aneurysmal hemorrhage posttreatment; in two patients this event proved to be fatal. Aneurysms with MGH Grades 0, 1, 2, 3, and 4 were associated with favorable outcomes (GOS scores of 5 or 4) in 100%, 92.8%, 71.4%, 50%, and 0% of instances, respectively. CONCLUSIONS: Despite a high incidence of transient complications, intracranial aneurysms that cannot be clipped or occluded require alternative surgical and endovascular treatment strategies. In those aneurysms that cannot safely be trapped or occluded, one approach is the treatment strategy of flow alteration.

Rheolytic thrombectomy of the occluded internal carotid artery in the setting of acute ischemic stroke.

BACKGROUND AND PURPOSE: Acute thromboembolic stroke complicated by ipsilateral carotid occlusion may present both mechanical and inflow-related barriers to effective intracranial thrombolysis. We sought to review our experience with a novel method of mechanical thrombectomy, in such cases, using the Possis AngioJet system, a rheolytic thrombectomy device. METHODS: A review of our interventional neuroradiology database revealed three patients in whom an occluded cervical internal carotid artery was encountered during endovascular treatment for acute stroke and in whom thrombectomy was attempted, using the 5F Possis AngioJet thrombectomy catheter. The medical records and radiographic studies of these patients were reviewed. RESULTS: Three patients were identified (ages, 52--84 years). Two patients had isolated occlusion of the internal carotid artery; in one patient, thrombus extended down into the common carotid artery. Treatment was initiated within 190 to 360 minutes of stroke onset. Thrombectomy of the carotid artery was deemed necessary because of poor collateral flow to the affected hemisphere (chronic contralateral internal carotid artery occlusion [one patient] and thrombus extending to the carotid "T" [one patient]) or inability to pass a microcatheter through the occluded vessel (one patient). Adjunctive therapy included pharmacologic thrombolysis with tissue plasminogen activator (all patients), carotid angioplasty and stenting (two patients), and middle cerebral artery angioplasty (one patient). Patency of the carotid artery was reestablished in two patients, with some residual thrombus burden. In the third patient, the device was able to create a channel through the column of thrombus, allowing intracranial access. CONCLUSION: Rheolytic thrombectomy shows potential for rapid, large-burden thrombus removal in cases of internal carotid artery thrombosis, allowing expedient access to the intracranial circulation for additional thrombolytic therapy.

Silent thromboembolic events associated with the treatment of unruptured cerebral aneurysms by use of Guglielmi detachable coils: prospective study applying diffusion-weighted imaging.

BACKGROUND AND PURPOSE: Aneurysm embolization using Guglielmi detachable coils (GDC) is gaining increasing acceptance as a viable alternative to surgery in the treatment of cerebral aneurysms. Although recent reports describe a significant rate of symptomatic thromboembolic complications with GDC use, many of the neurologic deficits are transient. We sought to determine the incidence of silent thromboembolic events with the use of diffusion-weighted imaging and to correlate radiologic findings with the results of neurologic examinations. METHODS: Diffusion-weighted MR imaging was performed within 48 hours in 14 consecutive elective GDC aneurysm treatments. Embolizations were performed under systemic heparinization; all flush solutions were heparinized, and both guiding catheters and microcatheters were placed for continuous heparinized infusions. Neurologic examination, including the National Institutes of Health Stroke Scale determination, was performed by a stroke neurologist before the coiling procedures were performed, immediately after the procedures were performed, and before discharge. MR imaging examinations were reviewed by a stroke neurologist and an interventional neuroradiologist, with determination and characterization of diffusion-weighted imaging abnormalities. RESULTS: Small areas of restricted diffusion, presumed to represent procedure-related embolic infarctions, were noted on the images of eight of 14 patients. All except one of the areas were located ipsilateral to the side of the catheterization. Six patients had evidence of multiple infarcts. Most lesions were small (<2 mm); one patient with coil stretch and herniation into the parent vessel had numerous infarcts with a dominant posterior frontal infarct. Pre- and posttreatment National Institutes of Health Stroke Scale scores were unchanged for 13 of 14 patients. Overall, the rate of asymptomatic emboli was 61% (eight of 13 treatments) in uncomplicated treatments. Strokes occurred independently of the number of coils used; the mean number of coils used for patients with strokes was 7.6 (range, two to 13) and for patients without evidence of infarcts was 10.2 (range, one to 30). This was not a significant difference (P > .5). CONCLUSION: Silent thromboembolic events related to the use of the GDC system are a common occurrence, despite meticulous technique and systemic anticoagulation. Although clinical sequelae are rare, the high rate of occurrence suggests that alterations in the technique, such as the addition of antiplatelet agents, should be considered.

Results after surgical and endovascular treatment of paraclinoid aneurysms by a combined neurovascular team.

OBJECTIVE: Advances in surgical and endovascular techniques have improved treatment for paraclinoid aneurysms. A combined surgical and endovascular team can formulate individualized treatment strategies for patients with paraclinoid aneurysms. Patients who are considered to be at high surgical risk can be treated endovascularly to minimize morbidity. We reviewed the clinical and radiographic outcomes of 238 paraclinoid aneurysms treated by our combined surgical and endovascular unit. METHODS: From 1991 to 1999, the neurovascular team treated 238 paraclinoid aneurysms in 216 patients at the Massachusetts General Hospital. The modality of treatment for each aneurysm was chosen based on anatomic and clinical risk factors, with endovascular treatment offered to patients considered to have higher surgical risks. One hundred eighty aneurysms were treated by direct surgery, 57 were treated by endovascular occlusion, and one was treated by surgical extracranial-intracranial bypass and endovascular internal carotid artery balloon occlusion. Locations were transitional, 12 (5%); carotid cave, 11 (5%); ophthalmic, 131 (55%); posterior carotid wall, 38 (16%); and superior hypophyseal 46 (19%). Lesions contained completely within the cavernous sinus were excluded from this analysis. RESULTS: Using the Glasgow Outcome Scale (GOS), overall clinical outcomes were excellent or good (GOS 5 or 4), 86%; fair (GOS 3), 7%; poor (GOS 2), 4%; and death (GOS 1), 3%. Among the surgically treated patients, 90% experienced excellent or good outcomes (GOS 5 or 4), 6% had fair outcomes (GOS 3), 2% had poor outcomes (GOS 2), and 3% died (GOS 1). Among the endovascularly treated patients, 74% had excellent or good outcomes (GOS 5 or 4), 12% had fair outcomes (GOS 3), 10% had poor outcomes (GOS 2), and 4% died (GOS 1). The overall major and minor complication rate from surgery was 29%, with a 6% surgery-related permanent morbidity rate and a mortality rate of 0%. The overall major and minor complication rate from endovascular treatment was 21%, with a 3% endovascular-related permanent morbidity rate and a 2% mortality rate. Visual outcomes for patients who presented with visual symptoms were as follows: improved, 69%; no change, 25%; worsened, 6%; and new visual deficits, 3%. In general, angiographic efficacy was lower in the endovascular treatment group. CONCLUSION: A combined team approach of direct surgery and endovascular coiling can lead to good outcomes in the treatment for paraclinoid aneurysms, including high-risk lesions that might not have been treated in previous surgical series.

Surgical and endovascular flow disconnection of intracranial pial single-channel arteriovenous fistulae.

INTRODUCTION: Intracranial pial single-channel arteriovenous (AV) fistulae are rare vascular lesions of the brain. They differ from AV malformations in that they lack a true "nidus" and are composed of one or more direct arterial connections to a single venous channel. They often are associated with a venous varix because of their high-flow nature. The pathological aspects of pial AV fistulae arise from their high-flow dynamics; therefore, we think that disconnection of the AV shunt is enough to obliterate the lesion, and that lesion resection is unnecessary. Flow disconnection can be accomplished via surgical or endovascular means. Certain lesions have angiogeometric configurations, however, that are unfavorable for endovascular treatment. We reviewed the experience in our combined neurosurgical and neuroendovascular unit in the treatment of patients with pial single-channel AV fistulae. METHODS: From 1991 to 1999, the combined neurovascular unit at the Massachusetts General Hospital treated nine consecutive patients with nontraumatic intracranial pial single-channel AV fistulae. Carotid-cavernous fistulae and vein of Galen malformations were excluded from this analysis. The combined neurovascular team planned the treatment strategy for each patient on the basis of the anatomic location and the angiogeometry of each lesion. We retrospectively reviewed the medical records, office charts, operative reports, endovascular reports, and x-rays for each patient. Radiographic outcome was assessed by use of posttreatment angiography. Clinical outcome was assessed by an independent nurse practitioner. RESULTS: A treatment strategy of flow disconnection was used in all nine patients and was accomplished surgically in six patients, endovascularly in two patients, and by combined techniques in one patient. All nine lesions were completely obliterated as demonstrated radiographically, including obliteration of the venous varices associated with three of the lesions. With a mean long-term clinical follow-up of 3.2 years (range, 0.3-8.4 yr), four patients were neurologically excellent with no deficits, two patients had pretreatment neurological deficits that did not worsen after treatment, one patient had transient dysphonia and dysphagia postoperatively that resolved, one patient had mild weakness after treatment, and one patient had moderate homonymous hemianopia after treatment. CONCLUSION: Single-channel pial AV fistulae can be treated by a strategy of flow disconnection. Resection of the lesion is not necessary. Flow disconnection can be accomplished either surgically or endovascularly; however, certain angiogeometric configurations are more favorable for surgical treatment. An experienced combined neurosurgical and neuroendovascular team can carefully determine the most appropriate treatment modality on the basis of patient-specific and angiospecific factors.

Management outcomes for ruptured and unruptured aneurysms in the elderly.

OBJECTIVE: In a patient older than 70 years, the decision to treat an intracranial aneurysm remains difficult whether it is ruptured or unruptured. We sought to review our institutional risks of treatment of such lesions in the context of the risks of rupture and its associated morbidity and mortality in this age group. METHODS: One hundred twenty-nine consecutive patients aged 70 years or older, who were treated at a single institution for an intracranial aneurysm, were retrospectively reviewed. Forty patients were treated for unruptured aneurysms, and 89 patients presented after subarachnoid hemorrhage. Seven additional patients in this age group who had solely intracavernous lesions, as well as one patient with a dolichoectatic fusiform basilar lesion, were excluded. Management outcomes were assessed using a modification of the Glasgow Outcome Scale, and additional physical and functional disability was assessed using the Barthel index and the Reintegration to Normal Living index. RESULTS: Six-month outcomes for the unruptured group were: excellent, 70%; good, 15%; fair, 5%; poor, 7.5%; and death (2.5%). Outcomes for all patients with ruptured lesions (including those not offered aggressive therapy) were: excellent, 34%; good, 9%; fair, 5.6%; poor, 3.4%; and death, 45%. Long-term follow-up was performed by questionnaire to assess physical and functional disability. Although physical disability (Barthel index) was similar among survivors, the Reintegration to Normal Living index, a global assessment of function, was significantly higher in patients with unruptured aneurysms (84.8 versus 70.1; P = 0.05), which highlights the disabling effects of hemorrhage. CONCLUSION: On the basis of an individual treatment center's management risks, annual aneurysmal rupture rates can be estimated that justify treatment in this difficult patient population. Despite recent controversy regarding aneurysmal hemorrhage rates, we think that symptomatic unruptured aneurysms should be treated and good results can be achieved, even in older patients.

Diffusion-weighted MR imaging: diagnostic accuracy in patients imaged within 6 hours of stroke symptom onset.

PURPOSE: To evaluate the diagnostic accuracy of diffusion-weighted magnetic resonance (MR) imaging performed within 6 hours of the onset of stroke symptoms. MATERIALS AND METHODS: The authors reviewed the patient records and images from all patients hospitalized in a 10-month period in whom diffusion-weighted imaging was performed within 6 hours of the onset of strokelike symptoms (n = 22). Analyses included comparison of the initial interpretation of the diffusion-weighted images with the final clinical diagnosis; blinded reviews of computed tomographic (CT) scans and conventional and diffusion-weighted images; and determination of lesion contrast-to-noise ratios (CNRs). RESULTS: Diffusion-weighted images indicated stroke in 14 patients, all of whom had a final diagnosis of acute stroke. Diffusion-weighted images were negative in eight patients, all of whom had a final clinical diagnosis other than stroke (100% sensitivity, 100% specificity, chi 2 = 23.00, P < .0001). Blinded reviews yielded 100% sensitivity and 86% specificity for diffusion-weighted MR imaging (chi 2 = 15.43, P < .0005); 18% sensitivity and 100% specificity for conventional MR imaging (chi 2 = 2.85, P > .2); and 45% sensitivity and 100% specificity for CT (chi 2 = 4.40, P > .10). Lesion percentage CNRs were 77% for diffusion-weighted imaging, 5.5% for CT, 9.8% for T2-weighted MR imaging, and 3.1% for proton-density-weighted MR imaging (P < .002 for diffusion-weighted imaging vs others). CONCLUSION: Diffusion-weighted MR imaging is highly accurate for diagnosing stroke within 6 hours of symptom onset and is superior to CT and conventional MR imaging.

Time course of lesion development in patients with acute stroke: serial diffusion- and hemodynamic-weighted magnetic resonance imaging.

BACKGROUND AND PURPOSE: We sought to characterize the evolution of acute ischemic stroke by MRI and its relationship to patients' neurological outcome. METHODS: Fourteen patients with acute ischemic stroke underwent MRI within 13 hours of symptom onset (mean, 7.4+/-3 hours) and underwent repeated imaging and concurrent neurological examination at 8, 24, 36, and 48 hours and 7 days and >42 days after first imaging. RESULTS: Diffusion-weighted imaging (DWI) lesion volumes increased between the first and second scans in 10 of 14 patients; scans with maximum DWI lesion volume occurred at a mean of 70.4 hours. Initial DWI lesion volume correlated with the largest T2 lesion volume (r=0.97; P<0.001). Final lesion volume was smaller than maximum lesion volume in 12 of 14 patients. There was positive correlation between the follow-up National Institutes of Health Stroke Scale score and the initial DWI lesion volume (r=0.67; P=0. 01) and maximum T2 lesion volume (r=0.77; P<0.01) and negative correlation with initial mean apparent diffusion coefficient ratio (ADCr) (r=-0.64; P<0.05). The ADCr was 0.73 at initial imaging and fell between the initial and second scans in 10 of 14 patients. Mean ADCr did not rise above normal until 42 days after stroke onset (P<0. 001). CONCLUSIONS: Serial MRI demonstrates the dynamic nature of progressive ischemic injury in acute stroke patients developing over hours to days, and it suggests that both primary and secondary pathophysiological processes can be valuable targets for neuroprotective interventions.

Regional ischemia and ischemic injury in patients with acute middle cerebral artery stroke as defined by early diffusion-weighted and perfusion-weighted MRI.

BACKGROUND AND PURPOSE: We sought to map early regional ischemia and infarction in patients with middle cerebral artery (MCA) stroke and compare them with final infarct size using advanced MRI techniques. MRI can now delineate very early infarction by diffusion-weighted imaging (DWI) and abnormal tissue perfusion by perfusion-weighted imaging (PWI). METHODS: Seventeen patients seen within 12 hours of onset of MCA stroke had MR angiography, standard MRI, and PWI and DWI MRI. PWI maps were generated by analysis of the passage of intravenous contrast bolus through the brain. Cerebral blood volume (CBV) was determined after quantitative analysis of PWI data. Volumes of the initial DWI and PWI lesion were calculated and compared with a final infarct volume from a follow-up imaging study (CT scan or MRI). RESULTS: Group 1 (10 patients) had MCA stem (M1) occlusion by MR angiography. DWI lesion volumes were smaller than the volumes of CBV abnormality. In 7 patients the final stroke volume was larger or the same, and in 3 it was smaller than the initial CBV lesion. Group 2 (7 patients) had an open M1 on MR angiography with distal MCA stroke. In 6 group 2 patients, the initial DWI lesion matched the initial CBV abnormality and the final infarct. CONCLUSIONS: Most patients with M1 occlusion showed progression of infarction into the region of abnormal perfusion. In contrast, patients with open M1 had strokes consistent with distal branch occlusion and had maximal extent of injury on DWI at initial presentation. Application of these MRI techniques should improve definition of different acute stroke syndromes and facilitate clinical decision making.

Imaging of cerebral metastases.

MR imaging with intravenous gadolinium has greatly enhanced our ability to detect and delineate intracranial metastases as well as to differentiate them from other disease processes. Techniques such as magnetization transfer and triple dose gadolinium imaging have further improved lesion detection. Consideration of these radiologic techniques, including the issues and controversies of screening and cost effectiveness, suggests a reasonable approach to imaging patients with possible intracranial metastases. Newer modalities such as echo planar imaging, spectroscopy, PET, and SPECT, may in the future, prove to be very useful in the evaluation of patients with intracranial metastases. Proper imaging is also critical to appropriate diagnosis and management of meningeal metastases, calvarial metastases, and paraneoplastic disease.

Lipomatous tumors of the pelvis in women: spectrum of imaging findings.

Pelvic tumors that contain fat are common findings in women. Although the majority of these lipomatous tumors are benign cystic ovarian teratomas, other diseases should be considered in the differential diagnosis: malignant degeneration of a benign cystic ovarian teratoma, nonteratomatous lipomatous ovarian tumors, lipomatous uterine tumors, benign pelvic lipomas, and pelvic liposarcomas. Although these diseases are rare, their differentiation can be clinically significant. While most of these tumors are treated by surgical excision, asymptomatic lipomatous uterine tumors and benign pelvic lipomas may require no therapy. Additionally, correct identification of a malignant lipomatous tumor will affect both prognosis and surgical planning. The purpose of this essay is to illustrate the imaging findings of these conditions.

Lipomatous uterine tumors: diagnosis by ultrasound, CT, and MR.

Lipomatous uterine tumors are rare benign neoplasms that can be difficult to differentiate from benign cystic ovarian teratomas. However, if a fat containing mass can be clearly identified to be of uterine origin, the diagnosis of a lipomatous uterine tumor can be made. We present two cases in which a lipomatous uterine tumor was suggested by ultrasound and confirmed by CT and magnetic resonance.