Clinical Neuroradiology最新文献

Background and purpose: Venous outflow (VO) impairment predicts unfavorable outcomes in patients with acute ischemic stroke caused by large vessel occlusion (AIS-LVO). Prolonged venous transit (PVT), a visual qualitative VO marker on CT perfusion (CTP) time to maximum (Tmax) maps, has been associated with 90-day mortality despite successful reperfusion. This study investigates the association between PVT and modified Rankin Scale (mRS) score at discharge among AIS-LVO patients who have undergone successful reperfusion.

Methods: We performed a retrospective analysis of prospectively collected data from consecutive adult AIS-LVO patients with successful reperfusion (modified Thrombolysis in Cerebral Infarction 2b/2c/3). PVT+ was defined as Tmax ≥ 10 s in at least one of the following locations: superior sagittal sinus and/or torcula. The primary outcome was dichotomous mRS scores at discharge (favorable: mRS 0-2; unfavorable: mRS 3-6). Regression analyses were performed to assess the effect of PVT on discharge mRS.

Results: In 119 patients of median (IQR) age 71 (63-81) years, a significantly higher proportion of PVT+ patients exhibited unfavorable mRS scores compared to PVT- patients (88.8% vs. 62.7%, p = 0.004). After adjusting for age, sex, hyperlipidemia, diabetes, history of stroke or transient ischemic attack (TIA), tobacco use, administration of intravenous thrombolysis (IVT), admission National Institutes of Health Stroke Scale (NIHSS), Alberta Stroke Program Early CT (ASPECTS) score, and ischemic core volume, the PVT+ remains significantly associated with unfavorable mRS (OR = 0.231, 95%CI 0.054-0.980, p = 0.047).

Conclusions: PVT+ was significantly associated with unfavorable mRS at discharge despite successful reperfusion in AIS-LVO patients, underscoring the importance of VO impairment in short-term functional outcomes. PVT serves as a valuable adjunct imaging biomarker derived from CTP for assessing VO profiles in AIS-LVO.

Purpose: Diffusion Weighted Imaging (DWI) represents the infarct core in acute ischemic stroke. DWI reversibility is a phenomenon reported for the anterior circulation affecting small brain areas of the white matter. This study aims to define DWI reversibility in the posterior circulation after successful recanalization of basilar artery occlusion (BAO) and its influence on patient outcome.

Methods: This was a retrospective analysis of two tertiary stroke-centers analyzing stroke patients between January 2015 and December 2022. Inclusion criteria were available MRI before and after acute stroke treatment and successful BAO recanalization. Brain areas were defined as brainstem, cerebellum and supratentorial brain areas supplied by the posterior circulation. These areas were compared in univariate analysis. Secondarily, patient outcome was compared between patients with DWI reversibility and patients without in univariate analysis with good outcome as primary endpoint (mRS 90d 0 to 2).

Results: In total, 5/28 of included patients (21.74%) showed DWI reversibility, which was exclusively found in the brainstem. The overall extent of brainstem infarction correlated better with patient outcome compared to cerebellar or supratentorial infarction (Spearman's ρ = 0.757; p < 0.001). Good outcome was more frequent in patients with DWI reversibility compared to those without (mRS 0-2, DWI+ n = 4, 80% vs. DWI- n = 6, 26%, p = 0.023).

Conclusion: DWI restriction reversibility was observed in the brainstem of acute stroke patients with BAO. In this study, patient outcome correlates stronger with the extent of brainstem infarction compared to cerebellar or supratentorial infarction.

Background: Patients with aneurysmal subarachnoid haemorrhage (aSAH) often receive multiple radiation based diagnostic studies. Cumulative radiation exposure has been associated with long term health consequences from both dose dependent deterministic harm and increased risk of developing adverse events in a non-dose dependant manner i.e. stochastic harm.

Objective: The objective was to calculate cumulative radiation exposure in the acute phase after aSAH.

Design, setting, participants, main outcome measures: Single centre retrospective, observational study of consecutive adult patients admitted to the ICU for management of aSAH over five years. Organ and effective radiation doses were determined using institution specific conversion coefficients based on scanner radiation output metrics for all computed tomography imaging and fluoroscopy examinations. Calculated patient doses for the duration of the hospital admission were determined using National Cancer Institute radiation dosimetry tools.

Results: A total of 276 patients met the inclusion criteria; 180 females (65%), mean (SD) age 56 (13) years. There were 222 (80%) patients who survived to hospital discharge. The median [IQR] effective cumulative radiation dose was 17.7 [9.7-30.5] mSv. Twenty-one patients (8%) received an effective dose > 50 mSV consistent with potentially harmful ionising radiation exposure. In 162 patients (59%), the equivalent radiation dose to the lens of the eye exceeded the 500 mSv threshold for radiation induced damage.

Conclusion: Survivors of aSAH are exposed to high levels of medical radiation. The eyes are particularly at risk with most patients exposed to levels known to induce lens damage. This highlights the importance of strategies to reduce incidental and cumulative medical radiation exposure in this population.

Background: Medium vessel occlusions (MeVO) can be either isolated events (primary), or secondary to thrombus migration from a large vessel occlusion to a medium-sized vessel. Outcomes following endovascular thrombectomy (EVT) in the middle cerebral artery (MCA) may differ between primary and secondary MeVOs. This study aimed to assess the association between primary/secondary MeVOs and clinical outcomes following EVT in a nationwide patient cohort.

Method: Patients undergoing EVT were included in two Swedish quality registries. Secondary MeVO was defined as distal migration of a solitary thrombus between baseline CT-angiography and EVT, or basal ganglia infarction on postoperative CT in a patient that presented with a single MeVO on baseline CT-angiography. The primary outcome was good 90-day functional outcome (modified Rankin Scale 0-2). Postoperative change in the National Institutes of Health Stroke Scale-score (NIHSS), was a secondary outcome. Successfully revascularized patients (mTICI 2b-3) were compared with non-revascularized patients in exploratory analyzes.

Results: Of the 5662 EVTs performed in Sweden (2018-2022), 1118 (20%) targeted solitary MCA territory MeVOs, with 819 (73%) being primary and 299 (27%) secondary. Functional outcomes did not differ between the primary and secondary MeVO groups (OR 0.86, CI 95% 0.65-1.14). Likewise, there was no significant difference in postoperative NIHSS scores (0.26, CI 95% -0.71 to 1.24), between groups (p = 0.597). Successful revascularization was associated with increased chance of good functional outcome for both primary (OR 3.77, CI95% 2.28-6.24, p < 0.001) and secondary MeVOs (OR 2.49, CI95% 1.21-5.14, p = 0.013).

Conclusions: Patients with a single primary or secondary MCA MeVOs have similar EVT outcomes and both groups seem to benefit from recanalization in exploratory analyses. This indicates that that EVT should not be withheld based on primary/secondary MeVO status.

Objectives: MRI is essential for monitoring multiple sclerosis (MS). Contrast-enhanced T1-weighted imaging (T1WI+C) detects active inflammatory lesions indicating blood-brain barrier breakdown and is relevant for disease monitoring and treatment optimization. Susceptibility-weighted imaging (SWI) may be included in the imaging protocol for detecting MS-specific features, such as the presence of central veins or paramagnetic rim lesions. However, post-contrast SWI (SWI+C) has an inherent "T1 shine-through effect" that enables the visualization of contrast-enhancing lesions. This study evaluates whether SWI+C in addition to standard T1WI+C improves the detection of enhancing lesions in patients with MS.

Materials and methods: The images of 310 patients with MS who underwent a standardized MRI protocol including T1WI+C and SWI+C using a 3T scanner were retrospectively reviewed. A neuroradiologist and radiology resident independently evaluated the images obtained on T1WI+C alone and T1WI+C plus SWI+C. The efficacy of T1WI+C alone was compared with that of T1WI+C plus SWI+C for detecting active enhancing MS lesions.

Results: The neuroradiologist detected 117 lesions on T1WI+C and 123 lesions on T1WI+C plus SWI+C. The resident detected 108 lesions on T1WI+C and 121 lesions on T1WI+C plus SWI+C. The interobserver agreement improved from 0.981 to 1.00 with the addition of SWI+C.

Conclusion: Adding SWI+C to standard T1WI+C consistently enhances the detection of active enhancing inflammatory MS lesions and the interobserver agreement. If standardized, this combined approach may allow for earlier detection of disease activity and improve monitoring of MS progression, potentially leading to optimized treatment decisions and improved patient outcomes.

Background: De- and acceleration traumata can cause diffuse axonal injury (DAI) in patients with traumatic brain injury (TBI). The diagnosis of DAI on CT is challenging due to the lack of structural abnormalities. Radiomics, a method from the field of artificial intelligence (AI) offers the opportunity to extract additional information from imaging data. The purpose of this work was the evaluation of the feasibility of radiomics for an improved diagnosis of DAI in comparison to conventional radiological image assessment.

Methods: CT and MR imaging was performed in 42 patients suspicious of DAI due to the clinical state, and two control groups (n = 44;42). DAI was diagnosed by experienced neuroradiologists. Radiomics features were extracted using a standardized MRI-based atlas of the predilection areas for DAI. Different MRI and CT based models were trained and validated by five-fold cross validation. Diagnostic performance was compared to the reading of two experienced radiologists and further validated in an external test dataset.

Results: The MRI and CT models showed significant differences in radiomics features between patients with DAI and controls. The developed MRI based random forest classifier yielded an accuracy of 80-90%. The best performing CT model yielded an accuracy of 88% in the training data and 70% in the external test data. The results were comparable to conventional image analysis which achieved an accuracy of 70-81% for CT-based diagnosis.

Conclusion: MRI- and CT-based radiomics analysis is feasible for the assessment of DAI. The radiomics classifier achieved equivalent performance rates as visual radiological image diagnosis. Especially a radiomics based CT classifier can be of clinical value as a screening and AI-based decision support tool for patients with TBI.

Objectives: Throughout the pandemic, it has become evident that COVID-19 should be recognized as a systemic disease that can affect the coagulation system, potentially resulting in arterial thrombotic events (ATE) with partially bulky free-floating clots. This study aimed to investigate the incidence and imaging characteristics of ATE in hospitalized patients with COVID-19 using clinical and imaging data.

Methods: From January 2020 to May 2021, databases of five German tertiary care centers were retrospectively screened for COVID-19 patients with coincidental ATE. ATE were analyzed for localization, time of occurrence, imaging characteristics, and associations with clinical data and laboratory parameters.

Results: Out of 3267 patients, 110 ATE (102 patients, mean age, 72.01 ± 15.64 years; 63 men) were observed in the presence of COVID-19 (3.1%). ATE included ischemic stroke (40%), myocardial infarction (46.4%, %), peripheral infarction (3.6%), thrombi in precerebral arteries (3.6%), mesenteric ischemia (2.7%), thrombi in the aorta (1.8%), splenic infarction (0.9%), and kidney infarction (0.9%). The median time interval between the onset of typical respiratory COVID-19 symptoms and ATE was four days (range, -5-58, negative values indicate ATE prior to symptom onset). A significant percentage of patients exhibited ATEs with an atypical free-floating appearance (10.0%) and multiple occlusions (21.2%).

Conclusion: COVID-19 is a systemic disease associated with ATE in all vascular regions, with a predilection for the heart and brain. The incidence of ATE might be higher than in comparable viral infections and ATE possibly exhibit distinct imaging features rarely seen, such as bulky free-floating clot masses and multiple occlusions. ATE occur most frequently during the first week around the COVID-19 diagnosis.

Purpose: Intracranial hemorrhage (ICH) is a life-threatening condition requiring rapid diagnostic and therapeutic action. This study evaluates whether Artificial intelligence (AI) can provide high-quality ICH diagnostics and turnaround times suitable for routine radiological practice.

Methods: A convolutional neural network (CNN) was trained and validated to detect ICHs on DICOM images of cranial CT (CCT) scans, utilizing about 674,000 individually labeled slices. The CNN was then incorporated into a commercial AI engine and seamlessly integrated into three pilot centers in Germany. A real-world test-dataset was extracted and manually annotated by two experienced experts. The performance of the AI algorithm against the two raters was assessed and compared to the inter-rater agreement. The overall time ranging from data acquisition to the delivery of the AI results was analyzed.

Results: Out of 6284 CCT examinations acquired in three different centers, 947 (15%) had ICH. Breakdowns of hemorrhage types included 8% intraparenchymal, 3% intraventricular, 6% subarachnoidal, 7% subdural, < 1% epidural hematomas. Comparing the AI's performance on a subset of 255 patients with two expert raters, it achieved a sensitivity of 0.90, a specificity of 0.96, an accuracy of 0.96. The corresponding inter-rater agreement was 0.84, 0.98, and 0.96. The overall median processing times for the three centers were 9, 11, and 12 min, respectively.

Conclusion: We showed that an AI algorithm for the automatic detection of ICHs can be seamlessly integrated into clinical workflows with minimal turnaround time. The accuracy was on par with radiology experts, making the system suitable for routine clinical use.

Purpose: The modified Rankin Scale (mRS) at 90 days is the primary outcome in most acute stroke studies, but the long follow-up period has disadvantages. The National Institutes of Health Stroke Scale (NIHSS) at 24 h shows a strong, but imperfect, association with 90-day mRS. This study examines the association between 24-hour NIHSS and 90-day mRS and reasons for discrepancies.

Methods: Data are from the ESCAPE-NA1 thrombectomy patients. To address the non-normality distribution of the NIHSS and include deceased patients, a 7-point ordinal score was generated by grouping 24-hour NIHSS. The association of ordinal 24-hour NIHSS and 90-day mRS was assessed with adjusted ordinal logistic regression. Differences in baseline and treatment/post-treatment variables were compared between patients with discordant and concordant outcomes.

Results: One-thousand-seventy-six patients with available 24-hour NIHSS and 90-day mRS were included (median 24-hour NIHSS 6[IQR: 2-14], median 90-day mRS 2[IQR: 1-4]). Ordinal 24-hour NIHSS was associated with 90-day mRS (adjusted cOR 2.53 [95%CI 2.33-2.74]). Forty-eight (4.5%) patients had discordant outcomes. Of those, 19(1.8%) had 24-hour NIHSS < 6 and 90-day mRS5-6; all of which had ≥ 1 severe adverse event, most commonly pneumonia (6[31.6%]) or recurrent stroke (4[21.1%]). Twenty-nine patients (2.7%) had 24-hour NIHSS > 14 and 90-day mRS 0-2. In these patients, baseline NIHSS and ASPECTS was lower, and collateral status was worse.

Conclusion: An ordinal NIHSS score that includes death at 24 h shows a strong association with 90-day mRS, suggesting that it could be used as an alternative outcome. Patients with discrepant outcomes differed from the remaining patients regarding their baseline NIHSS, ASPECTS, collateral status, and post-stroke complications.