3D movement correction of CT brain perfusion image data of patients with acute ischemic stroke

Introduction

Head movement during CT brain perfusion (CTP) acquisition can deteriorate the accuracy of CTP analysis. Most CTP software packages can only correct in-plane movement and are limited to small ranges. The purpose of this study is to validate a novel 3D correction method for head movement during CTP acquisition.

Methods

Thirty-five CTP datasets that were classified as defective due to head movement were included in this study. All CTP time frames were registered with non-contrast CT data using a 3D rigid registration method. Location and appearance of ischemic area in summary maps derived from original and registered CTP datasets were qualitative compared with follow-up non-contrast CT. A quality score (QS) of 0 to 3 was used to express the degree of agreement. Furthermore, experts compared the quality of both summary maps and assigned the improvement score (IS) of the CTP analysis, ranging from ?2 (much worse) to 2 (much better).

Results

Summary maps generated from corrected CTP significantly agreed better with appearance of infarct on follow-up CT with mean QS 2.3 versus mean QS 1.8 for summary maps from original CTP (P?=?0.024). In comparison to original CTP data, correction resulted in a quality improvement with average IS 0.8: 17 % worsened (IS?=??2, ?1), 20 % remained unchanged (IS?=?0), and 63 % improved (IS?=?+1, +2).

Conclusion

The proposed 3D movement correction improves the summary map quality for CTP datasets with severe head movement.     

Multimodal CT assessment of acute ischemic stroke

Aim of the work

To evaluate the role of multimodal CT [non-enhanced CT (NECT), CT perfusion (CTP), and CT angiography (CTA)] in selection of acute ischemic stroke patients for reperfusion therapy.

Patients and methods

This prospective study included 35 patients with evidence of acute stroke in the middle cerebral artery territory of less than 12 h duration. Patients underwent multimodal CT including: (1) NECT (2) CTP (3) CTA. Qualitative and quantitative interpretation of the CTP was done to differentiate penumbra and infarction. CTA was evaluated for arterial occlusion or stenosis and the presence of collaterals.

Results

The areas of infarction showed a significant decrease in CBF (p = 0.03) and CBV values (p = 0.01) compared to the corresponding area in the contralateral normal hemisphere. The areas of penumbra showed a significant decrease in CBF (p = 0.04) and insignificant difference in CBV (p = 0.2) compared to the corresponding area in the contralateral normal hemisphere. Cutoff values of 2.0 for the CBV and MTT > 130% of the contralateral normal hemisphere allowed the best differentiation of infarction and penumbra.

Conclusion

Multimodal CT imaging fulfills all the requirements for selection of patients for reperfusion therapy and so helps in stroke treatment decisions.     

Prediction of motor outcome in ischemic stroke involving the pyramidal tract using diffusion tensor imaging

Background and purpose

Early evaluation of the pyramidal tract is a prerequisite in patients with ischemic stroke in order to decide the optimal treatment or to assess appropriate rehabilitation. The aim of this study was to predict motor outcome using quantitative and qualitative diffusion tensor parameters and their correlations with severity of stroke as defined by the National Institutes of Health Stroke Scale (NIHSS).

Materials and methods

Twenty-one patients presenting with ischemic stroke were studied with DTI. All patients had diffusion measurements such as FA values of the affected and unaffected regions and the FA ratio between them. Color FA maps of the pyramidal tract were constructed and the degree of infarctions was classified into groups according to the involvements of the pyramidal tracts. The motor performance of the upper and lower extremities was assessed using the NIHSS on the day of patients’ admission and discharge. The motor outcomes were correlated with the FA values of the pyramidal tract.

Results

The FA values of the affected pyramidal tracts were significantly lower as compared with the unaffected side (p-value <0.01). The reduction in the FA values of the affected side was significantly correlated (r = 0.41 and p-value <0.001) with the degree of pyramidal tract involvements that were significantly correlated with the motor outcome on patients’ discharge day.

Conclusions

Quantitative (FA values) and qualitative (the diffusion tensor tractography) diffusion parameters have potential to predict motor outcome in patients with ischemic stroke.     

Leptomeningeal collateralization in acute ischemic stroke: Impact on prominent cortical veins in susceptibility-weighted imaging

Background

The extent of hypoperfusion is an important prognostic factor in acute ischemic stroke. Previous studies have postulated that the extent of prominent cortical veins (PCV) on susceptibility-weighted imaging (SWI) reflects the extent of hypoperfusion. Our aim was to investigate, whether there is an association between PCV and the grade of leptomeningeal arterial collateralization in acute ischemic stroke. In addition, we analyzed the correlation between SWI and perfusion-MRI findings.

Methods

33 patients with acute ischemic stroke due to a thromboembolic M1-segment occlusion underwent MRI followed by digital subtraction angiography (DSA) and were subdivided into two groups with very good to good and moderate to no leptomeningeal collaterals according to the DSA. The extent of PCV on SWI, diffusion restriction (DR) on diffusion-weighted imaging (DWI) and prolonged mean transit time (MTT) on perfusion-imaging were graded according to the Alberta Stroke Program Early CT Score (ASPECTS). The National Institutes of Health Stroke Scale (NIHSS) scores at admission and the time between symptom onset and MRI were documented.

Results

20 patients showed very good to good and 13 patients poor to no collateralization. PCV-ASPECTS was significantly higher for cases with good leptomeningeal collaterals versus those with poor leptomeningeal collaterals (mean 4.1 versus 2.69; p = 0.039). MTT-ASPECTS was significantly lower than PCV-ASPECTS in all 33 patients (mean 1.0 versus 3.5; p < 0.00).

Conclusions

In our small study the grade of leptomeningeal collateralization correlates with the extent of PCV in SWI in acute ischemic stroke, due to the deoxyhemoglobin to oxyhemoglobin ratio. Consequently, extensive PCV correlate with poor leptomeningeal collateralization while less pronounced PCV correlate with good leptomeningeal collateralization. Further SWI is a very helpful tool in detecting tissue at risk but cannot replace PWI since MTT detects significantly more ill-perfused areas than SWI, especially in good collateralized subjects.     

Dynamic CT Perfusion Imaging for the Detection of Crossed Cerebellar Diaschisis in Acute Ischemic Stroke

Objective

Although the detection of crossed cerebellar diaschisis (CCD) by means of different imaging modalities is well described, little is known about its diagnosis by computed tomography perfusion (CTP) imaging. We investigated the detection rate of CCD by CTP imaging and the factors related to CCD on CTP images in patients with acute ischemic stroke.

Materials and Methods

CT perfusion maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time-to-peak (TTP) obtained from 81 consecutive patients affected by an acute ischemic stroke were retrospectively reviewed. Whole-brain perfusion maps were obtained with a multichannel CT scanner using the toggling-table technique. The criteria for CCD was a unilateral supratentorial ischemic lesion and an accompanying decrease in perfusion of the contralateral cerebellar hemisphere on the basis of CTP maps by visual inspection without a set threshold. Maps were quantitatively analyzed in CCD positive cases.

Results

The criteria for CCD were fulfilled in 25 of the 81 cases (31%). Detection rates per CTP map were as follows: MTT (31%) > TTP (21%) > CBF (9%) > CBV (6%). Supratentorial ischemic volume, degree of perfusion reduction, and infratentorial asymmetry index correlated strongly (R, 0.555-0.870) and significantly (p < 0.05) with each other in CCD-positive cases.

Conclusion

It is possible to detect CCD on all four of the CTP-based maps. Of these maps, MTT is most sensitive in detecting CCD. Our data indicate that CTP imaging is a valid tool for the diagnosis of CCD in patients affected by an acute hemispheric stroke.     

Prognostic factors related to clinical outcome following thrombectomy in ischemic stroke (RECOST Study). 50 patients prospective study

Background and aims

New thrombectomy devices allow successful and rapid recanalization in acute ischemic stroke. Nevertheless prognostics factors need to be systematically analyzed in the context of these new therapeutic strategies. The aim of this study was to analyze prognostic factors related to clinical outcome following Solitaire FR thrombectomy in ischemic stroke.

Methods

Fifty consecutive ischemic stroke patients with large vessel occlusion were included. Three treatment strategies were applied; rescue therapy, combined therapy, and standalone thrombectomy. DWI ASPECT score < 5 was the main exclusion criterion after initial MRI (T2, T2*, TOF, FLAIR, DWI). Sexes, age, time to recanalization were prospectively collected. Clinical outcome was assessed post treatment, day one and discharge by means of a NIHSS. Three months mRS evaluation was performed by an independent neurologist.The probability of good outcome at 3 months was assessed by forward stepwise logistic regression using baseline NIHSS score, Glasgow score at entrance, hyperglycemia, dyslipidemia, blood–brain barrier disruption on post-operative CT, embolic and hemorrhagic post procedural complication, ischemic brain lesion extension on 24 h imaging, NIHSS at discharge, ASPECT score, and time to recanalization. All variables significantly associated with the outcome in the univariate analysis were entered in the model. The significance of adding or removing a variable from the logistic model was determined by the maximum likelihood ratio test. Odds-ratio (OR) and their 95% confidence intervals were calculated.

Results

At 3 months 54% of patients had a mRS 0–2, 70% in MCA, 44% in ICA, and 43% in BA with an overall mortality rate of 12%. Baseline NIHSS score (p = 0.001), abnormal Glasgow score at entrance (p = 0.053) hyperglycemia (p = 0.023), dyslipidemia (p = 0.031), blood–brain barrier disruption (p = 0.022), embolic and hemorrhagic post procedural complication, ischemic brain lesion extension on 24 h imaging (p = 0.008), NIHSS at discharge (0.001) were all factors significantly associated with 3 month clinical outcome. ASPECT subgroup (5–7 and 8–10), and time to recanalization were not correlated to 3 months outcome. Baseline NIHSS score (OR, 1.228; 95% CI, 1.075–1.402; p = 0.002), hyperglycemia (OR, 10.013; 95% CI, 1.068–93.915; p = 0.04), emerged as independent predictors of outcome at 3 months. Overall embolic complication rate was 10%, and symptomatic intracranial hemorrhage was 2%.

Conclusion

The MCA location was associated with the best clinical outcome. A DWI ASPECT cutoff score of 5 was reliable and safe. No correlation with time to recanalization was observed in this study. NIHSS and hyperglycemia at admission were the two factors independently associated with a bad outcome at 90 days.     

Carotid Artery Stent Placement and Carotid Endarterectomy: A Challenge for Urgent Treatment after Stroke—Early and 12-Month Outcomes in a Comprehensive Stroke Center

Purpose

To compare feasibility, 12-month outcome, and periprocedural and postprocedural risks between carotid artery stent (CAS) placement and carotid endarterectomy (CEA) performed within 1 week after transient ischemic attack (TIA) or mild to severe stroke onset in a single comprehensive stroke center.

Changes in cerebral hemodynamics after carotid stenting of symptomatic carotid artery

Purpose

To evaluate changes in cerebral hemodynamics after carotid stenting of symptomatic carotid artery in the patients who underwent ischemic stroke caused by carotid artery stenosis.

Methods

Twenty patients with unilateral symptomatic carotid artery stenosis received brain computer tomography perfusion (CTP) scan a week before and a week after carotid artery stenting. Three absolute values including mean transit time (MTT), cerebral blood volume (CBV), and cerebral blood flow (CBF) were acquired and analyzed by use of the post-processing software. Six vascular territories such as ACA territory, MCA territory, PCA territory, basal ganglia, watershed between ACA and MCA territory (frontal watershed), watershed between MCA and PCA territory (posterior watershed) were chosen for comparison. Relative parameter values were defined as rCBF (relative CBF), rCBV (relative CBV), rMTT (relative MTT) through comparing absolute values in symptomatic hemispheres to absolute values in asymptomatic hemispheres. The relative perfusion parameter values before treatment were compared with post-treatment values. These analyses were performed by using the paired t test.

Results

The mean rMTT decreased significantly in ACA territory, MCA territory and two watershed after treatment, while the mean rCBF increased significantly in those areas after treatment. But the mean rCBV had no significant changes in all six vascular territories. In PCA territory, all the parameters had no significant changes.

Conclusion

Carotid artery stenting yields satisfactory cerebral perfusion in ACA territory, MCA territory, basal ganglia and two watersheds.     

Clinical usefulness of the visibility of the transcerebral veins at 3T on T2*-weighted sequence in acute stroke patients

Objectives

The objective of this work was to investigate the clinical usefulness of the visibility of the transcerebral veins (VTV) in acute ischemic stroke patients at 3 T.

Methods

Sixty consecutive carotid artery territory stroke patients were included retrospectively. Two readers categorized the VTV on T2*-weighted sequence at 3 T for each hemisphere, and asymmetry of this sign was assessed between each hemisphere by an asymmetry index (AI) using a three-item scale. The VTV and AI were correlated with clinical and radiological covariates. Particular interest was focused on patients for whom initial diffusion-weighted imaging alone was inconclusive.

Results

VTV were detected in the stroke hemisphere in 58.3% (n = 35) and in the contralateral side in 10% (n = 6, p < 0.0001). Asymmetry of the VTV between ischemic and contralateral hemispheres was present in 53.3% (n = 32). Intracranial artery occlusion, final infarct volume and symptomatic hemorrhagic transformation were correlated with a higher AI at baseline (ρ = 0.563, ρ = 0.291, and ρ = 0.285, p < 0.05, respectively). Three hyperacute stroke patients with subtle DWI high signal intensity at admission demonstrated VTV.

Conclusions

The pathological value of the VTV seems to reside in its asymmetry between hemispheres, as it was correlated with important clinical parameters. This study also suggests that the VTV could be a supportive finding in stroke diagnosis, especially when DWI is unreliable.     

The value of b0 images obtained from diffusion-weighted echo planar sequences for the detection of intracranial hemorrhage compared with GRE sequence

Purpose

Our aim was to evaluate the clinical utility of b0EPI images obtained from diffusion sequence for the detection of the intracranial hemorrhagic lesions, especially acute intracerebral bleeds thereby shorten the scan time particularly in the critical acute cases of stroke.

Materials and methods

Among all consecutive MR brain studies performed in our department last year, we retrospectively selected those who followed the following criteria: (1) clinically suspected or radiographically confirmed acute infarction or hemorrhage. (2) MRI imaging including DWI and T2∗ images. Sensitivity of hemorrhage detection, conspicuity of lesions, and diagnostic certainty were compared between the b0EPI and GRE sequences.

Results

There were 77 hemorrhagic lesions with a variety of pathogeneses in various locations. 76/77 (98.7%) of these lesions were hemorrhagic (hypointense) on the GRE sequences, whereas 61 (79.2%) were characterized as hemorrhagic on b0EPI images, and 16 (20.8%) were not detected. The overall difference in hemorrhage conspicuity/diagnostic certainty between GRE and b0EPI sequences was statistically significant (P < .05).

Conclusion

b0EPI sequence, although shorter in acquisition time, was inferior to GRE imaging in the detection of acute and chronic intracerebral hemorrhage.     

Brain magnetic resonance imaging findings in cryptogenic stroke patients under 60 years with patent foramen ovale

Purpose

To compare magnetic resonance imaging (MRI) brain feature in cryptogenic stroke patients with patent foramen ovale (PFO), cryptogenic stroke patients without PFO and patients with cardioembolic stroke.

Materials and methods

The ethics committee required neither institutional review board approval nor informed patient consent for retrospective analyses of the patients’ medical records and imaging data. The patients’ medical files were retrospectively reviewed in accordance with human subject research protocols. Ninety-two patients under 60 years of age were included: 15 with cardioembolic stroke, 32 with cryptogenic stroke with PFO and 45 with cryptogenic stroke without PFO. Diffusion-weighted imaging of brain MRI was performed by a radiologist blinded to clinical data. Univariate, Fischer's exact test for qualitative data and non-parametric Wilcoxon test for quantitative data were used.

Results

There was no statistically significant difference found between MRI features of patients with PFO and those with cardioembolic stroke (p < .05). Patients without PFO present more corticosubcortical single lesions (p < .05) than patients with PFO. Patients with PFO have more often subcortical single lesions larger than 15 mm, involvement of posterior cerebral arterial territory and intracranial occlusion (p < .05) than patients with cryptogenic stroke without PFO.

Conclusion

Our study suggests a cardioembolic mechanism in ischemic stroke with PFO.     

Hypoattenuation on CTA images with large vessel occlusion: timing affects conspicuity

Purpose

Parenchymal hypoattenuation distal to occlusions on CTA source images (CTASI) is perceived because of the differences in tissue contrast compared to normally perfused tissue. This difference in conspicuity can be measured objectively. We evaluated the effect of contrast timing on the conspicuity of ischemic areas.

Methods

We collected consecutive patients, retrospectively, between 2012 and 2014 with large vessel occlusions that had dynamic multiphase CT angiography (CTA) and CT perfusion (CTP). We identified areas of low cerebral blood volume on CTP maps and drew the region of interest (ROI) on the corresponding CTASI. A second ROI was placed in an area of normally perfused tissue. We evaluated conspicuity by comparing the absolute and relative change in attenuation between ischemic and normally perfused tissue over seven time points.

Results

The median absolute and relative conspicuity was greatest at the peak arterial (8.6 HU (IQR 5.1–13.9); 1.15 (1.09–1.26)), notch (9.4 HU (5.8–14.9); 1.17 (1.10–1.27)), and peak venous phases (7.0 HU (3.1–12.7); 1.13 (1.05–1.23)) compared to other portions of the time-attenuation curve (TAC). There was a significant effect of phase on the TAC for the conspicuity of ischemic vs normally perfused areas (P < 0.00001).

Conclusion

The conspicuity of ischemic areas distal to a large artery occlusion in acute stroke is dependent on the phase of contrast arrival with dynamic CTASI and is objectively greatest in the mid-phase of the TAC.

     

The clinical value of antiplatelet therapy for patients with hemorrhage after thrombolysis based on susceptibility-weighted imaging: A prospective pilot study

Purpose

To evaluate treatment decision-making based on susceptibility-weighted imaging (SWI) in patients with hemorrhage after thrombolysis.

Materials and methods

One hundred and forty-six patients without intracranial hemorrhage on CT after receiving recombinant tissue plasminogen activator (rt-PA) were allocated to two groups: antiplatelets (n = 72), who received antiplatelet therapy 24 h after rt-PA for 10 days; and non-antiplatelets (n = 74), who received no antiplatelet therapy. Twenty-two patients with SWI-detected microbleeds (MBs) or hemorrhagic transformation (HT) in the antiplatelets group (Group A) and 28 with MB or HT in the non-antiplatelets group (Group B) were included in this study.

Results

Sixteen patients had MB and six HT in Group A; 18 had MB, six HT, and four parenchymal hemorrhage (PH) in Group B. National Institutes of Health Stroke Scale (NIHSS) scores at 7 and 14 days and the Modified Rankin Scale (mRS) at 90 days post-rt-PA were significantly lower in Group B than in Group A, duration of hospitalization was significantly shorter, and the favorable outcome rate was higher at 90 days (P < 0.05). There were no other significant differences. SWI evaluation at 14 days revealed eight patients with MB, 11 HT, and three PH in Group A; in Group B, 16 had MB, five HT, and one PH, with resolution of hemorrhage in six patients.

Conclusions

Treatment decision-making based on SWI in acute stroke after thrombolysis was validated by the significantly reduced NIHSS score after 7/14 days, improved outcome, and reduced mRS in hemorrhage patients without antiplatelet therapy.     

Value of pre-intervention CT perfusion imaging in acute ischemic stroke prognosis

Noninvasive imaging plays an important role in acute stroke towards diagnosis and ongoing management of patients. Systemic thrombolysis and endovascular thrombectomy (EVT) are proven treatments currently used in standards of care in acute stroke settings. The role of computed tomography angiography (CTA) in selecting patients with large vessel occlusion for EVT is well established. However, the value of CT perfusion (CTP) imaging in predicting outcomes after stroke remains ambiguous. This article critically evaluates the value of multimodal CT imaging in early diagnosis and prognosis of acute ischemic stroke with a focus on the role of CTP in delineating tissue characteristics, patient selection, and outcomes after reperfusion therapy. Insights on various technical and clinical considerations relevant to CTP applications in acute ischemic stroke, recommendations for existing workflow, and future areas of research are discussed.

Neuroimaging is currently the mainstay of acute stroke workflow as it is used to rule out hemorrhage and select patients eligible for systemic thrombolysis and endovascular thrombectomy (EVT) (1). Advanced imaging has shown promise in acute stroke; however, the prognostic utility of computed tomography perfusion (CTP) imaging has drawn considerable debate. Given that stroke is associated with long-term morbidity and mortality, efforts to develop diagnostic imaging biomarkers have been pursued. However, the clinical translation of certain imaging modalities has been limited, especially CTP imaging. This could be attributed to the limited availability of CTP in under-resourced settings, variations in the diagnostic accuracy of CTP maps, and differences in the thresholds used in creating perfusion maps. In this paper, we will present a comprehensive overview of various imaging modalities in acute stroke with a particular focus on the clinically relevant utility of CTP and provide roadmap for future research.     

Clinical impact of MRI perfusion disturbances and normal diffusion in acute stroke patients

Purpose

In acute ischemic stroke MR-imaging typically shows diffusion abnormalities surrounded by reduced perfusion signifying the so-called ischemic penumbra. Mismatch between diffusion and perfusion abnormalities gives indication for thrombolysis. But is there an indication for thrombolytic treatment, if there is no diffusion abnormality but pathologic perfusion combined with acute stroke symptoms?.

Material and methods

MR-imaging of 1465 patients treated on our Stroke Unit between June 2004 and May 2007 retrospectively are analyzed. 6 patients met the inclusion criteria of severe neurological symptoms, large territorial perfusion disturbances, lack of diffusion abnormalities and complete neurological recovery after treatment.

Results

In all six patients MTT measurements showed a significantly depressed perfusion in the symptomatic hemisphere (p < 0.02). Time-to-peak delay correlated with the mean transit time delay (0.949, p < 0.01). Indication for thrombolysis was based on perfusion abnormalities and clinical symptoms. Stroke symptoms could be reversed in all patients without any complication.

Conclusion

Whereas diffusion imaging could not reveal any abnormality, perfusion analysis legitimated therapy with systemic thrombolysis in heavily affected patients. This work underlines the importance of multimodal MR imaging for guiding treatment decisions in acute stroke patients.     

FLAIR lesion segmentation: Application in patients with brain tumors and acute ischemic stroke

Background

Lesion size in fluid attenuation inversion recovery (FLAIR) images is an important clinical parameter for patient assessment and follow-up. Although manual delineation of lesion areas considered as ground truth, it is time-consuming, highly user-dependent and difficult to perform in areas of indistinct borders. In this study, an automatic methodology for FLAIR lesion segmentation is proposed, and its application in patients with brain tumors undergoing therapy; and in patients following stroke is demonstrated.

Materials and methods

FLAIR lesion segmentation was performed in 57 magnetic resonance imaging (MRI) data sets obtained from 44 patients: 28 patients with primary brain tumors; 5 patients with recurrent-progressive glioblastoma (rGB) who were scanned longitudinally during anti-angiogenic therapy (18 MRI scans); and 11 patients following ischemic stroke.

Results

FLAIR lesion segmentation was obtained in all patients. When compared to manual delineation, a high visual similarity was observed, with an absolute relative volume difference of 16.80% and 20.96% and a volumetric overlap error of 24.87% and 27.50% obtained for two raters: accepted values for automatic methods. Quantitative measurements of the segmented lesion volumes were in line with qualitative radiological assessment in four patients who received anti-anogiogenic drugs. In stroke patients the proposed methodology enabled identification of the ischemic lesion and differentiation from other FLAIR hyperintense areas, such as pre-existing disease.

Conclusion

This study proposed a replicable methodology for FLAIR lesion detection and quantification and for discrimination between lesion of interest and pre-existing disease. Results from this study show the wide clinical applications of this methodology in research and clinical practice.     

Tratamiento endovascular de estenosis intracraneales sintomáticas: resultados a corto y largo plazo de un único centro

Objectives

We present the short- and long-term results of a series of patients with symptomatic intracranial arterial stenoses treated with angioplasty and stenting.

Material and methods

We reviewed patients with symptomatic intracranial stenoses greater than 50% who were treated with angioplasty, stenting, or both. We recorded demographic data and risk factors (hypertension, diabetes, dyslipemia, ischemic heart disease). We classified all lesions treated according to their location, degree of stenosis, and length. The degree of stenosis was classified as moderate (50%-70%) or severe (>70%). In the follow-up, we assessed cerebrovascular accidents, episodes of ischemic heart disease, and deaths in the first 30 days and in later follow-up.

Results

Between 2006 and 2010, we treated 26 patients (21 men and 5 women; age range, 44-79 years; mean age, 63 years) with 29 intracranial lesions. The endovascular procedure (angioplasty + stenting) was successfully performed in 23 cases (92.0%). In the first 30 days after the procedure, 3 (11.5%) patients had adverse effects of vascular origin: 1 stroke, 1 hemorrhage, and 1 death due to thrombosis of the stent. Long-term follow-up (5-46 months) in the 25 patients who survived more than 30 days detected no recurrence of symptoms.

Conclusion

Endovascular treatment of intracranial stenosis is technically feasible. Short-term complications are highly prevalent. No recurrence of symptoms was detected during long-term follow-up.     

Role of CT enterography in assessment of Crohn’s disease activity: Correlation with histopathologic diagnosis

Aim

To evaluate the radiological signs of gastro-intestinal inflammation at CT enterography and to assess its accuracy in determining the degree of activity in patients with Crohn’s disease (CD).

Methods

CT enterography was performed in 26 CD patients and evaluated for the following parameters: mucosal enhancement, abnormal wall thickening, engorged vasa recta, increased density of the mesenteric fat and enlarged mesenteric lymph nodes. Correlations between CT findings and histopathologic results were made using McNemar test.

Results

There was no significant statistical difference in mucosal enhancement and wall thickening between moderate and severe disease (P = 0.631 and 0.138, respectively) whereas engorged vasa recta, fat edema and lymph node enlargement had successfully discriminated between moderate and severe histological findings (P = 0.009, <0.001 and 0.045, respectively). Moderate disease was diagnosed correctly by CTE in 50% of cases while severe disease was diagnosed in 100% of cases. When we reconditioned the presence of two CTE severity criteria to diagnose severe disease, the sensitivity to predict moderate disease activity increased to 80%.

Conclusion

CT enterography is a sensitive and specific non-invasive imaging modality for evaluating the degree of activity of Crohn’s disease, and should be considered in its diagnostic and management algorithms.     

Perfusion measurement of the whole upper abdomen of patients with and without liver diseases: initial experience with 320-detector row CT

Objectives

To report initial experience of upper abdominal perfusion measurement with 320-detector row CT (CTP) for assessment of liver diseases and therapeutic effects.

Materials and methods

Thirty-eight patients who were suspected of having a liver disease underwent CTP. There were two patients with liver metastases, two with hemangiomas, and four with cirrhosis (disease group). CTP was repeated for four patients with cirrhosis or hepatocellular carcinoma (HCC) after therapy. Hepatic arterial and portal perfusion (HAP and HPP) and arterial perfusion fraction (APF), and arterial perfusion (AP) of pancreas, spleen, stomach, and intra-portal HCC were calculated. For disease-free patients (normal group), the values were compared among liver segments and among pancreatic and gastric parts. The values were compared between groups and before and after therapy.

Results

No significant differences were found in the normal group except between APFs for liver segments 3 and 5, and fundus and antrum. Mean HAP and APF for the disease group were significantly higher than for the normal group. APF increased after partial splenic embolization or creation of a transjugular intrahepatic portosystemic shunt. HPP increased and AP of intra-portal HCC decreased after successful radiotherapy.

Conclusions

320-Detector row CT makes it possible to conduct perfusion measurements of the whole upper abdomen. Our preliminary results suggested that estimated perfusion values have the potential to be used for evaluation of hepatic diseases and therapeutic effects.     

Normal values of quantitative T2' in a spontaneously hypertensive stroke prone rat stem at 3T

Introduction

Regarding therapy and prognosis of acute ischemic stroke the identification of ischemic penumbra is pivotal. A promising candidate is BOLD-imaging using qT2′-maps. For valid interpretation of experimental studies in animals normal values for qT2′ are needed. Normal values in humans at 1.5 T already exist. Normal values for cortical and subcortical structures in a spontaneously hypertensive stroke prone rat stem (SHR-SP) at a fieldstrength of 3 T are reported.

Materials and methods

39 (20 males and 19 females) spontaneously hypertensive stroke prone (SHRSP) rats were examined in a 3 T scanner using a dedicated small animal coil. Mean weight was 144.1 ± 8.2 g and mean age was 60.2 ± 2.7 days. For the calculation of qT2′ multiple echo T2w and T2*w images were acquired. ROIs were placed into deep and cortical grey matter in five different brain regions to obtain values for qT2′, qT2 and qT2*.

Results

Mean qT2′ for cortical grey matter was 74.76 ± 33.27 ms and 67.73 ± 17.86 ms for deep grey matter. The 99% confidence interval for cortical grey matter was 69.91–79.61 ms. For qT2 it was 79.02 ± 2.9 ms and 70.45 ± 1.89 ms, respectively. For qT2* it was 34.65 ± 5.25 ms and 31.9 ± 2.99 ms.

Conclusion

The values for qT2′ presented here can serve as reference values for further studies examining the ischemic penumbra in a rat model.