Early and late infarct growth rate in ischemic stroke patients after successful endovascular treatment in early time window: correlation of imaging and clinical factors with clinical outcome

Background

The prospective study assessed infarct growth rate (IGR) in acute ischemic stroke (AIS) with large vessel occlusion (LVO) after recanalization in early time window. Early IGR (EIGR) and late IGR (LIGR) were correlated with imaging and clinical data; we searched for outcome predictors.

Methods

We included 71 consecutive patients. Subjects underwent computed tomography perfusion (CTP) for ischemic core volume assessment at 99.0 minutes (median) from stroke onset, recanalization was performed at 78.0 minutes (median) from CTP. Final infarct volume (FIV) was measured on 24±2 hours imaging follow-up. EIGR was calculated as the core volume/time between stroke onset and CTP; LIGR was calculated as FIV/time between CTP and imaging follow-up. Twenty-two subjects were assessed as poor outcome, 49 as good outcome. Group differences were tested by Mann-Whitney test and χ2 test. Bayesian logistic regression models were used to predict clinical outcome, Pearson correlations for the log-transformed predictors.

Results

Subjects with poor outcome were older, median age 78.0 [interquartile range (IQR): 71.8, 83.8] versus 68.0 (IQR: 57.0, 73.0) years; 95% confidence interval (CI): 6.00 to 16.00; P<0.001. Their stroke severity scale was higher, median 19.0 (IQR: 16.0, 20.0) versus 15.5 (IQR: 10.8, 18.0); 95% CI: 1.00 to 6.00; P<0.001. They had higher EIGR, median 23.9 (IQR: 6.4, 104.0) versus 6.7 (IQR: 1.7, 13.0) mL/h; 95% CI: 3.26 to 53.68; P=0.002; and larger core, median 52.5 (IQR: 13.1, 148.5) versus 10.0 (IQR: 1.4, 20.0) mL; 95% CI: 11.00 to 81.00; P<0.001. In subjects with poor outcome, infarct growth continued after thrombectomy with LIGR 2.0 (IQR: 1.2, 9.7) versus 0.3 (IQR: 0.0, 0.7) mL/h; 95% CI: 1.10 to 6.10; P<0.001; resulting in larger FIV, median 186.5 (IQR: 49.3, 280.8) versus 18.5 (IQR: 8.0, 34.0) mL; 95% CI: 55.30 to 214.00; P<0.001. Strong correlations among predictors were found e.g., core and EIGR (r=0.942), LIGR and FIV (r=0.779), core and FIV (r=0.761). Clinical outcome was best predicted using data from later measurements as FIV and LIGR.

Conclusions

Data from later measurements were more predictive, there was no major benefit to use growth over volume data.

CT Brain Perfusion in the Prediction of Final Infarct Volume: A Prospective Study of Different Software Settings for Acute Ischemic Core Calculation

CT perfusion (CTP) is used for the evaluation of brain tissue viability in patients with acute ischemic stroke (AIS). We studied the accuracy of three different syngo.via software (SW) settings for acute ischemic core estimation in predicting the final infarct volume (FIV). The ischemic core was defined as follows: Setting A: an area with cerebral blood flow (CBF) < 30% compared to the contralateral healthy hemisphere. Setting B: CBF < 20% compared to contralateral hemisphere. Setting C: area of cerebral blood volume (CBV) < 1.2 mL/100 mL. We studied 47 AIS patients (aged 68 ± 11.2 years) with large vessel occlusion in the anterior circulation, treated in the early time window (up to 6 h), who underwent technically successful endovascular thrombectomy (EVT). FIV was measured on MRI performed 24 ± 2 h after EVT. In general, all three settings correlated with each other; however, the absolute agreement between acute ischemic core volume on CTP and FIV on MRI was poor; intraclass correlation for all three settings was between 0.64 and 0.69, root mean square error of the individual observations was between 58.9 and 66.0. Our results suggest that using CTP syngo.via SW for prediction of FIV in AIS patients in the early time window is not appropriate.

Diagnosis of Ischemic Stroke: As Simple as Possible

The absolute majority of strokes in high-income countries, roughly 91%, are of ischemic origin. This review is focused on acute ischemic stroke (AIS) with large vessel occlusion (LVO) in the anterior circulation, which is considered the most devastating subtype of AIS. Moreover, stroke survivors impose substantial direct and indirect costs of care as well as costs due to productivity loss. We review of diagnostic possibilities of individual imaging methods such as computed tomography and magnetic resonance imaging, and discuss their pros and cons in the imaging of AIS. The goals of non-invasive imaging in AIS are as follows: (a) to rule out intracranial hemorrhage and to quickly exclude hemorrhagic stroke and contraindications for intravenous thrombolysis; (b) to identify potential LVO and its localization and to quickly provide guidance for endovascular treatment; (c) to assess/estimate the volume or size of the ischemic core. We suggest fast diagnostic management, which is able to quickly satisfy the above-mentioned diagnostic goals in AIS with LVO.

Spontaneous spinal epidural haematoma: management and main risk factors in era of anticoagulant / antiplatelet treatment

AIM OF THE STUDY

Spontaneous spinal epidural haematomas (SSEH) are rare nosological units wherein acute collections of blood develop in the spinal canal. SSEH are usually manifested by sudden severe back pain accompanied by the development of neurological symptoms. In this study, we retrospectively describe management and the main risk factors of SSEH in a series of 14 cases.

MATERIAL AND METHODS

Between 2010 and 2019, we examined 14 patients (age range 17-89 years, 10 women) diagnosed with SSEH. Eight cases were patients using anticoagulant therapies (six warfarin, one dabigatran, one apixaban) and two others were using ASA of 100 mg/day. The exact localisation and extent of changes was determined from acute magnetic resonance imaging. Three people using warfarin had INR values higher than 3.0 at the time of their diagnosis.

RESULTS

Ten patients (71%) were taking oral anticoagulants or antiplatelet agents. In seven patients, SSEH were localised in the lower cervical/thoracic spine. Ten patients (71%) had arterial hypertension. Six patients underwent acute surgery due to rapidly developing spinal cord compression. Eight patients (57%) with slight or mild neurological symptoms were successfully managed without surgery.

CONCLUSIONS

SSEH should be suspected in any patient receiving anticoagulant/antiplatelet agents who complains of sudden, severe back pain accompanied by neurological symptoms. SSEH is mostly localised in the lower cervical/thoracic spine. Arterial hypertension appears to be a risk factor of SSEH. Early decompression is an important therapeutic approach; in cases with minor neurological deficits, conservative treatment may be chosen.

Advanced cervical cancer in young women: imaging study of late and very late radiation-related side effects after successful treatment by combined radiotherapy

Background

Radical combined radiotherapy (RT) is a standard treatment for advanced cervical cancer. The aim of our study was to identify morphological late (≥6 months) and very late (≥5 years) radiation-related comorbidities on computed tomography (CT), positron emission tomography/computerized tomography (PET/CT) or magnetic resonance imaging (MRI) scans in young females who survived ≥5 years since RT and were considered as successfully treated. Secondly, we studied a rate of clinically silent radiation-related toxicities apparent on imaging scans that might influenced on future well-being of survived females. Thirdly, we analyzed reasons why patients underwent imaging scans.

Methods

We included 41 subjects aged under 50 years (mean 41.8±7.2 years, median 41 years), who survived ≥5 years since RT, with at least one available imaging scan ≥3 years since RT. The mean time between RT and the last available scan was 12.3±7.9 years (median 9 years); the mean time of clinical follow-up was 15.4±7.1 years (median 14 years).

Results

Fourteen (34.1%) females underwent the first imaging scan in emergency situation and 27 (65.9%) patients due to variable chronic complaints. Grade III-V radiation-related comorbidities occurred in 19 (46.3%) females including one case of death due to radiation-induced osteosarcoma. In 14 of 19 patients, comorbidities were multiple. Four (9.8%) females suffered from life-threatening complications (grade IV): one from an uretero-arterial fistula with massive hematuria and 3 from bowel perforations. Eleven (26.8%) subjects suffered from bowel strictures with ileus development, they underwent mean 1.7±0.8 surgery (median 1.5). The mean time since RT to the first surgery for intestinal complications was 5.4±6.0 years (median 3 years), to the second 12.0±9.6 years (median 11.5 years) and to the third surgery 9.0±4.2 years (median 9 years). Late fistulas formations (vesico-recto-vaginal) were seen in 6 (14.6%) patients. Bone complications were diagnosed in 9 (22.0%) of treated females, one case of osteosarcoma included, 4 of 9 bone complications were clinically silent. In 5 (12.2%) subjects, toxicities grade III-IV first time manifested >5 years since RT, majority of them were multiple. The bowel perforation and fistulas formations were the earliest manifested grade III-IV toxicities, with median time 3 years since RT, the bone complications were the latest manifested with median time 16 years since RT.

Conclusions

Our study is not able to bring information about the incidence of late and very late radiation related comorbidities, according to International Federation of Gynecology and Obstetrics (FIGO) recommendations patients are clinically followed only for 5 years and imaging cross-sectional scans are not recommended. However, our study shows that if females successfully treated for advanced cervical cancer report abdominal/pelvic clinical problems, it is highly probable their imaging scans will reveal late radiation related side-effects that may affect the rest of their life. It puts forward question whether females after radical RT should been regularly followed by cross-sectional imaging methods.

Review of the structural and functional brain changes associated with chronic kidney disease

Chronic kidney disease (CKD) leads to profound metabolic and hemodynamic changes, which damage other organs, such as heart and brain. The brain abnormalities and cognitive deficit progress with the severity of the CKD and are mostly expressed among hemodialysis patients. They have great socio-economic impact. In this review, we present the current knowledge of involved mechanisms.

Is limited-coverage CT perfusion helpful in treatment decision-making in patients with acute ischemic stroke?

Background

The initial core infarct volume predicts treatment outcome in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). According to the literature, CT perfusion (CTP) is able to evaluate cerebral parenchymal viability and assess the initial core in AIS. We prospectively studied whether limited-coverage CTP with automated core calculation correlates with the final infarct volume on follow-up non-enhanced CT (NECT) in patients successfully treated by mechanical thrombectomy.

Methods

We enrolled 31 stroke patients (20 women aged 74.4±12.9 years and 11 men aged 66±15.4 years; median initial NIHSS score 15.5) with occlusion of the medial cerebral artery and/or the internal carotid artery that were treated by successful mechanical thrombectomy. CTP performed in a 38.6 mm slab at the level of basal ganglia was included in the CT stroke protocol, but was not used to determine indication for mechanical thrombectomy. The infarction core volume based on CTP was automatically calculated using dedicated software with a threshold defined as cerebral blood flow <30% of the value in the contralateral healthy hemisphere. The final infarction volume was measured on 24-hour follow-up NECT in the same slab with respect to CTP. Pearson and Spearman correlation coefficients and robust linear regression were used for comparison of both volumes, P values <0.05 were considered as statistically significant.

Results

The median time from stroke onset to CT was 77 minutes (range, 31-284 minutes), and the median time from CT to vessel recanalization was 95 minutes (range, 55-215 minutes). The mean CTP-calculated core infarct volume was 24.3±19.2 mL (median 19 mL, range 1-79 mL), while the mean final infarct volume was 21.5±39.5 mL (median 8 mL; range 0-210 mL). Only a weak relationship was found between the CTP-calculated core and final infarct volume [Pr₍₂₉₎ =0.32, P=0.078; rho =0.40, P=0.028]. Regression analysis showed CTP significantly overestimated lower volumes.

Conclusions

In our prospective study, the infarction core calculated using limited-coverage CTP only weakly correlated with the final infarction volume measured on 24-hour follow-up NECT; moreover, CTP significantly overestimated lower volumes. Our results do not support the use of limited-coverage CTP for guiding treatment recommendations in patients with AIS.

[Whole-Body CT Scan and Other Imaging Techniques in Examining Polytrauma Patients - Outcomes of a Questionnaire Survey of Trauma Centres in the Czech Republic]

PURPOSE OF THE STUDY The study aimed to map the use of imaging techniques and results reporting in polytrauma patients by the trauma centres in the Czech Republic. MATERIAL AND METHODS The representatives of radiology departments and units of all 12 trauma centres in the Czech Republic completed a questionnaire regarding the imaging in polytrauma patients. RESULTS The Focused Assessment with Sonography for Trauma (FAST) as an initial imaging is used by all the centres, the WholeBody CT scan (WBCT) is the dominant imaging technique everywhere and all the centres have standards in place for its performance. The WBCT examination protocol varies across the centres, just like the evaluation procedures of the CT scan and reporting of the results over to the indicating physicians. In majority of centres, there is a high percentage of WBCT with normal findings. One of the centres which uses also X-rays as a part of imaging algorithm, reports a notably higher percentage of WBCT positive findings. DISCUSSION When considering the radiation dose, data and time necessary for WBCT, work required to assess the WBCT and a large number of negative findings, it is disputable whether in a number of cases the WBCT is a suitable method for polytrauma patient examination. Similar conclusions have been drawn also by other authors who recommend that the WBCT is always used for unconscious polytrauma patients, in whom a clinical examination is virtually impossible. In the other cases, based on the clinical parameters the other imaging techniques and the focused CT (and in the indicated cases also the wholebody CT) can be safely used. CONCLUSIONS he diagnostic procedure in a polytrauma patient is not uniform in trauma centres and even the procedure for urgent reporting of crucial WBCT findings to clinical physicians has not been standardised. In a number of cases the indication for WBCT seems to be unnecessary. A more careful consideration of indications for imaging examinations based on the clinical finding may reduce the radiation exposure of patients while maintaining the diagnostic accuracy. A structured report on WBCT in polytrauma is not used even though it is recommended by the European Society of Radiology. Key words:polytrauma, diagnostic imaging, Whole-Body Computed Tomography, structured report.

Hypophysitis and other autoimmune complications related to immune checkpoints inhibitors´ treatment: Spectrum of imaging appearances

OBJECTIVES

Immune checkpoints inhibitors (ICI) represent a new therapy option for the treatment of several advanced tumors. However, this therapy has been linked to a spectrum of ICI related autoimmune (AI) adverse events. Some may be life threatening and their diagnosis is tricky. The aim of our study was to describe various imaging appearances of ICI related secondary hypophysitis and other coincidental AI diseases.

MATERIAL AND METHODS

We included 28 patients (19 females, 9 men, mean aged 58±13 years), who were consecutively treated mostly for advanced stage melanoma by different ICI. All their CT/MRI records and clinical data were reviewed.

RESULTS

We found 5 (18%) cases of endocrinology proven secondary hypophysitis; 2 cases of panhypopituitarism and 3 cases of central hypocortisolism. Four cases were MRI positive, 1 case was MRI negative. Three cases were accompanied by other AI diseases: 1 by hemorrhagic colitis and mesenterial lymphadenitis, 1 by AI pancreatitis and 1 by pneumonitis. On MRI pituitary gland was swollen in 3 cases, twice enhanced non-homogenously, once homogenously; infundibular enlargement was present in 2 cases. Those 3 cases reacted to glucocorticoid therapy by hypophyseal shrinkage. In 1 case of MRI positive hypophysitis, the pituitary gland was not enlarged, slightly nonhomogeneous with peripheral contour enhancement; no reaction to glucocorticoids was mentioned.

CONCLUSION

Secondary hypophysitis is probably more common ICI related adverse event than reported in the literature. Its MRI appearance is variable. Most of our cases were in coincidence with other AI ICI related events that affected their clinical manifestations.

Secondary central nervous system lymphoma: spectrum of morphological MRI appearances

BACKGROUND

Secondary central nervous system lymphoma (SCNSL) is a rare and aggressive disease, which is defined as secondary central nervous system (CNS) involvement in patients with systemic lymphoma. According to previous reports, SCNSL presents mostly with leptomeningeal spread; however, our experience differs. In the present study, we demonstrate the diversity of magnetic resonance imaging (MRI) patterns in SCNSL.

PATIENTS AND METHODS

Initial morphological MRI findings in 21 patients (10 women and 11 men with mean age 62.3±16.2 years) with SCNSL were retrospectively evaluated. All patients suffered from neurological symptoms and underwent MRI, and all cases were histologically verified. Twelve patients were treated by corticosteroids at the time of the initial MRI.

RESULTS

Parenchymal lesions were present in 18 of 21 cases (85.7%), solitary meningeal infiltration was present in 1 patient (4.8%), leptomeningeal infiltration in combination with hypophyseal involvement in 1 patient (4.8%), and solitary involvement of the sixth cranial nerve (CN) was found in 1 patient (4.8%). Multiple lesions were present in 11 of 21 cases (52.4%). Diffusion restriction in all or part of the lesion was detected in 14 of 18 cases (77.8%). All parenchymal lesions had an infiltrative appearance and most enhanced homogenously (11 of 17 cases; 64.7%). A combination of parenchymal and meningeal involvement was found in 10 of 21 cases (47.6%). Infiltration of the CNs, basal ganglia, corpus callosum, and ependyma was present in 8 of 21 cases (38.1%) for each of the abovementioned structures; hypothalamic-hypophyseal axis was affected in 7 of 21 cases (33.3%).

CONCLUSION

In contrast to previous reports, SCNSL presented as parenchymal disease. MRI is not sufficient for differentiation between primary and secondary CNS lymphoma.

Can morphological MRI differentiate between primary central nervous system lymphoma and glioblastoma?

Background

Primary central nervous system lymphoma (PCNSL) is a rare, aggressive brain neoplasm that accounts for roughly 2-6% of primary brain tumors. In contrast, glioblastoma (GBM) is the most frequent and severe glioma subtype, accounting for approximately 50% of diffuse gliomas. The aim of the present study was to evaluate morphological MRI characteristics in histologically-proven PCNSL and GBM at the time of their initial presentation.

Methods

We retrospectively evaluated standard diagnostic MRI examinations in 54 immunocompetent patients (26 female, 28 male; age 62.6 ± 11.5 years) with histologically-proven PCNSL and 54 GBM subjects (21 female, 33 male; age 59 ± 14 years).

Results

Several significant differences between both infiltrative brain tumors were found. PCNSL lesions enhanced homogenously in 64.8% of cases, while nonhomogeneous enhancement was observed in 98.1% of GBM cases. Necrosis was present in 88.9% of GBM lesions and only 5.6% of PCNSL lesions. PCNSL presented as multiple lesions in 51.9% cases and in 35.2% of GBM cases; however, diffuse infiltrative type of brain involvement was observed only in PCNSL (24.1%). Optic pathways were infiltrated more commonly in PCNSL than in GBM (42.6% vs. 5.6%, respectively, p <0.001). Other cranial nerves were affected in 5.6% of PCNSL, and in none of GBM. Signs of bleeding were rare in PCNSL (5.6%) and common in GBM (44.4%); p < 0.001. Both supratentorial and infratentorial localization was present only in PCNSL (27.7%). Involvement of the basal ganglia was more common in PCNSL (55.6%) than in GBM (18.5%); (p < 0.001). Cerebral cortex was affected significantly more often in GBM (83.3%) than in PCNSL (51.9%); mostly by both enhancing and non-enhancing infiltration.

Conclusion

Routine morphological MRI is capable of differentiating between GBM and PCNSL lesions in many cases at time of initial presentation. A solitary infiltrative supratentorial lesion with nonhomogeneous enhancement and necrosis was typical for GBM. PCNSL presented with multiple lesions that enhanced homogenously or as diffuse infiltrative type of brain involvement, often with basal ganglia and optic pathways affection.

Central nervous system lymphoma: a morphological MRI study

OBJECTIVES

The aim of the present study was to evaluate morphological MRI findings in histologically-proven central nervous system lymphoma (CNSL) at time of their first appearance, and to describe dynamic changes on repeat MRI before the diagnosis was histologically proven.

METHODS

We retrospectively evaluated the MRI examinations of 74 patients with histologically-proven CNSL (10 secondary CNSL, 64 primary PCNSL; 10 immunocompromised, 54 immunocompetent). In 43 patients, we evaluated the evolution of CNSL on MRI before the diagnosis was proven.

RESULTS

Primary CNSL was typically localized supratentorially (63%), with multiple (59%) or infiltrative (36%) lesions showing diffusion restriction (98%), often (87%) reaching the brain surface. In approximately 50% of patients, meningeal, ependymal or cranial nerve involvement was found. We detected significant differences in enhancement patterns between immunocompromised and immunocompetent patients; non-homogenous enhancement present in 50% of immunocompromised patients. We did not find any significant differences in MRI appearance between primary and secondary CNSL. Regression was evident after corticosteroid treatment in 52% of patients; however, in 16% of cases overall progression was observed.

CONCLUSION

CNSL generally presents as an infiltrative lesion or multiple homogenously-enhancing lesions of the brain in contact with the brain surface. Involvement of the corpus callosum, cranial nerves, ependyma or meninges is common. No significant differences between primary and secondary CNSL were detected, however differences in enhancement type between immunocompromised and immunocompetent primary CNSL patients were found. We stress the variability of MRI findings in the course of the disease and also the variable response to corticotherapy.

Late morphological changes after radiosurgery of brain arteriovenous malformations: an MRI study

BACKGROUND

Radiosurgery by Gamma Knife (GK) is an effective treatment for brain arteriovenous malformations (AVM). The aim of the present study was to evaluate late, radiation-induced changes detectable by MRI after AVM radiosurgery in patients treated minimally 10 years prior, with AVM obliteration proven by angiography.

METHODS

Thirty-five patients with 37 AVMs were included. AVMs were irradiated 16.6 ± 3.5 years prior with AVM obliteration proven 13 ± 4 years prior. All patients underwent recent MRI examinations, including application of gadolinium-based contrast.

RESULTS

In one case, post-irradiative cystic formation with mass effect and signs of hemorrhage requiring surgery was found. Post-gadolinium enhancement at the site of obliterated nidi was apparent in 28 of 37 cases (76 %). In all cases except one, the mean volume of enhancement at the time of review was clearly lower than the volume of the originally irradiated AVM (88 ± 20 %; median 92 %); in one case the extent was 142 % greater than the irradiated AVM. When we compared enhancing and non-enhancing nidi, we found that enhancing nidi were significantly larger than non-enhancing nidi at the time of radiosurgery (4.39 ± 3.35 cc vs. 0.89 ± 0.79 cc, p = 0.004). Enhancement was not influenced by total radiation dose, patient age at the time of irradiation, duration since radiosurgery, or the number of irradiations. Wallerian degeneration was found in nine of 37 cases (24 %); in six cases the optical tracts were affected and visual field defects were proven. In five of nine cases (55.6 %) with Wallerian degeneration previous hemorrhage was present. Dual vascular pathology was found in eight of 35 patients (23 %).

CONCLUSIONS

GK radiosurgery for AVM is a safe treatment method although delayed complications may occur. Post-gadolinium enhancement of obliterated nidi may indicate an active post-irradiative process.

Anatomical predictors for successful pulmonary vein isolation using balloon-based technologies in atrial fibrillation

PURPOSE

We evaluated the correlation between pulmonary venous (PV) anatomy and acute and long-term success of PV isolation (PVI) with two balloon-based ablation catheter techniques.

METHODS

One hundred consecutive patients were analyzed in two equal groups treated with either the second-generation cryoballoon (CRYO) catheter or the visually guided laser ablation (VGLA) catheter. All patients underwent multi-detector computed tomography (CT) imaging. The primary and secondary efficacy endpoints were the procedural achievement of proven electrical isolation of all veins and freedom from atrial fibrillation (AF) within a 1-year follow-up period, respectively.

RESULTS

Variant PV anatomy was observed in 32% of patients in the CRYO group and in 40% of patients in the VGLA group. All PVs were targeted with either the CRYO catheter (n = 199) or the VGLA catheter (n = 206). One hundred ninety-three of 199 PVs (97%) were successfully isolated in the CRYO group and 194 of 206 PVs (94%) in the VGLA group (p = 0.83). Over a 12-month follow-up, AF recurrence was documented in 11/45 (24%) and 7/43 (16%) patients in the CRYO and the VGLA groups, respectively (p = 0.21). In the CRYO group, a larger left inferior PV size was associated with worse long-term outcome (p = 0.001). In the VGLA group, a larger left superior PV size (p = 0.003) and more oval right inferior PV were associated with worse acute success (p = 0.038). There was no absolute cutoff between PV anatomy and clinical success.

CONCLUSIONS

The variability of PV anatomy did not significantly compromise acute success of PVI or patient outcomes.

The Benefits of High Relaxivity for Brain Tumor Imaging: Results of a Multicenter Intraindividual Crossover Comparison of Gadobenate Dimeglumine with Gadoterate Meglumine (The BENEFIT Study)

BACKGROUND AND PURPOSE

Gadobenate dimeglumine (MultiHance) has higher r1 relaxivity than gadoterate meglumine (Dotarem) which may permit the use of lower doses for MR imaging applications. Our aim was to compare 0.1- and 0.05-mmol/kg body weight gadobenate with 0.1-mmol/kg body weight gadoterate for MR imaging assessment of brain tumors.

MATERIALS AND METHODS

We performed crossover, intraindividual comparison of 0.1-mmol/kg gadobenate with 0.1-mmol/kg gadoterate (Arm 1) and 0.05-mmol/kg gadobenate with 0.1-mmol/kg gadoterate (Arm 2). Adult patients with suspected or known brain tumors were randomized to Arm 1 (70 patients) or Arm 2 (107 patients) and underwent 2 identical examinations at 1.5 T. The agents were injected in randomized-sequence order, and the 2 examinations were separated by 2-14 days. MR imaging scanners, imaging sequences (T1-weighted spin-echo and T1-weighted high-resolution gradient-echo), and acquisition timing were identical for the 2 examinations. Three blinded readers evaluated images for diagnostic information (degree of definition of lesion extent, lesion border delineation, visualization of lesion internal morphology, contrast enhancement) and quantitatively for percentage lesion enhancement and lesion-to-background ratio. Safety assessments were performed.

RESULTS

In Arm 1, a highly significant superiority (P < .002) of 0.1-mmol/kg gadobenate was demonstrated by all readers for all end points. In Arm 2, no significant differences (P > .1) were observed for any reader and any end point, with the exception of percentage enhancement for reader 2 (P < .05) in favor of 0.05-mmol/kg gadobenate. Study agent-related adverse events were reported by 2/169 (1.2%) patients after gadobenate and by 5/175 (2.9%) patients after gadoterate.

CONCLUSIONS

Significantly superior morphologic information and contrast enhancement are demonstrated on brain MR imaging with 0.1-mmol/kg gadobenate compared with 0.1-mmol/kg gadoterate. No meaningful differences were recorded between 0.05-mmol/kg gadobenate and 0.1-mmol/kg gadoterate.

View-Synchronized Robotic Image-Guided Therapy for Atrial Fibrillation Ablation

Background— A robotic catheter navigation system has been developed that provides a significant degree of freedom of catheter movement. This study examines the feasibility of synchronizing this robotic navigation system with electroanatomic mapping and 3-dimensional computed tomography imaging to perform view-synchronized left atrial (LA) ablation.

Methods and Results— This study consisted of a porcine experimental validation phase (9 animals) and a clinical feasibility phase (9 atrial fibrillation patients). Preprocedural computed tomography images were reconstructed to provide 3-dimensional surface models of the LA pulmonary veins and aorta. Aortic electroanatomic mapping was performed manually, followed by registration with the corresponding computed tomography aorta image using custom software. The mapping catheter was remotely manipulated with the robotic navigation system within the registered computed tomography image of the LA pulmonary veins. The point-to-surface error between the LA electroanatomic mapping data and the computed tomography image was 2.1±0.7 and 1.6±0.1 mm in the preclinical and clinical studies, respectively. The catheter was remotely navigated into all pulmonary veins, the LA appendage, and circumferentially along the mitral valve annulus. In 7 of 9 animals, circumferential radiofrequency ablation lesions were applied periostially to ablate 11 pulmonary veins. In patients, all of the pulmonary veins were remotely electrically isolated in an extraostial fashion. Adjunctive ablation included superior vena cava isolation in 6 patients, cavotricuspid isthmus ablation in 5 patients, and ablation of sites of complex fractionated activity and atypical LA flutters in 3 patients.

Conclusions— This study demonstrates the safety and feasibility of an emerging paradigm for atrial fibrillation ablation involving the confluence of 3 technologies: 3-dimensional imaging, electroanatomic mapping, and remote robotic navigation.

Integration of cardiac CT/MR imaging with three-dimensional electroanatomical mapping to guide catheter manipulation in the left atrium: implications for catheter ablation of atrial fibrillation

INTRODUCTION

Preprocedural cardiac imaging (CT/MRI) and intraprocedural electroanatomical mapping (EAM) are commonly used during left atrial (LA) catheter ablation of atrial fibrillation (AF). In the optimal scenario, the imaging datasets would be directly integrated with the EAM system to guide catheter mapping based on the accurate individual cardiac anatomy.

METHODS AND RESULTS

Strategies to align the EAM and imaging data were assessed by simulations using a life-size model of the LA and aorta. This revealed that the optimal strategy includes mapping both the aorta and LA. Respiratory changes in cardiac anatomy were evaluated by MR angiography performed in 10 patients during both inspiration and expiration. Comparison of paired images revealed inferior and anterior movement of the LA relative to the aorta with inspiration. Next, image integration was employed in a series of patients (n = 13) scheduled for AF catheter ablation. After preprocedural CT angiography (7 during inspiration and 6 during expiration), three-dimensional anatomical renderings of these images were integrated with the EAM data in a custom workstation to permit real-time catheter manipulation within these constructs. The electrophysiologist was blinded to these integrated images, but the accuracy of the process was assessed real-time by a second operator. This revealed poor alignment during inspiration but good alignment during expiration--the respiratory phase most closely resembling that during EAM.

CONCLUSIONS

This study supports the feasibility of integrating preacquired cardiac images with real-time electroanatomical mapping to guide catheter movement in the LA in a reliable and clinically relevant manner.

Relationship of the esophagus and aorta to the left atrium and pulmonary veins: Implications for catheter ablation of atrial fibrillation

BACKGROUND

A potential complication during ablation of atrial fibrillation (AF) is damage to adjacent structures such as the esophagus and aorta. Fatal atrio-esophageal fistulas have developed after surgery- or catheter-based AF ablation procedures.

OBJECTIVES

The purpose of this study was to analyze multidetector computed tomography (MDCT) angiographic images to determine the anatomic relationship of the aorta and esophagus to the left atrium (LA).

METHODS

Sixty-five subjects underwent CT imaging using a 16-slice MDCT scanner: 24 with paroxysmal AF, 21 with chronic AF, and 20 "control" subjects without a history of AF. Measurements assessed included LA diameters, width of the esophagus and aorta in contact with the posterior LA wall, and distance from the esophagus to the four pulmonary veins (PVs), spine, and LA endocardium.

RESULTS

Mean LA diameters were significantly larger in patients with AF vs the control group (P = .003 for anteroposterior diameter; P = .009 for transverse diameter). The anterior aspect of the esophagus was directly apposed to the LA in all cases (contact width 18.9 +/- 4.4 mm). The position of the esophagus varied in the posterior mediastinum but on average was closer to the ostia of the left PVs (P = .0001). The descending aorta was in contact with the LA and/or left PVs in 50 of 65 subjects. The esophagus was closer to the spine in the chronic AF vs control group (P = .007), likely due to increased LA dimension.

CONCLUSION

In addition to its ability to assess PV anatomy, preprocedural MDCT imaging can investigate the variable relationship of adjacent structures, such as the esophagus and aorta to the LA and PVs.

[Initial experience with magnetic resonance cholangiopancreatography]

BACKGROUND

Magnetic resonance cholangiopancreaticography (MRCP) is based on heavily weighted T2 sequences (ETSE--echo-train spin echo) with suppression of fat, giving visualisation of slowly flowing or stagnating fluid. MRCP are short sequences in coronary plane with thickness of 8 cm or 4 mm. Retrospective analysis of all MRCP examinations performed during last 12 months is presented.

METHODS AND RESULTS

Eighty-eight examinations were done, of which 67 ones with both adequate technical quality and clinical indication were included into the study (20 males aged 25-83 years, 47 women aged 19-82 years). Patients were divided into 4 groups regarding to the indications (group I.--temporary cholestasis, normal abdominal ultrasound, II.--definite cholestasis, III.--pathologic findings on pancreas, IV.--other). Vast majority of patients were included into group I (35 subjects). In 7 (20%) of them choledocholithiasis and/or stenoses (including multiple stenoses in primary sclerotizing cholangoitis) were found. MRCP brought diagnostic information in subjects with cholestasis (group II.) and answered questions given by clinicians. However, in 1 of 4 subjects with primary sclerotizing cholangoitis, MRCP did not reveal intra-hepatic stenoses, which were later visualised by classical ERCP. Only the extrahepatic stenoses were diagnosed by MRCP in the latter subject.

CONCLUSIONS

MRCP should become a standard examination in the diagnostic algorithm in patients with cholangiopathies. MRCP has its value not only in subjects with unsuccessful or contraindicated ERCP, but also in subjects with temporary cholestasis with negative ultrasound finding.