ABSTRACT
BACKGROUND: Existing radiological markers of hematoma expansion (HE) show modest predictive accuracy. We aim to investigate a novel radiological marker that co-localizes findings from non-contrast CT (NCCT) and CT angiography (CTA) to predict HE. METHODS: Consecutive acute intracerebral hemorrhage patients admitted at Foothills Medical Centre in Calgary, Canada, were included. The Black-&-White sign was defined as any visually identified spot sign on CTA co-localized with a hypodensity sign on the corresponding NCCT. The primary outcome was hematoma expansion (⩾6 mL or ⩾33%). Secondary outcomes included absolute (<3, 3-6, 6-12, ⩾12 mL) and relative (0%, <25%, 25%-50%, 50%-75%, or >75%) hematoma growth scales. RESULTS: Two-hundred patients were included, with 50 (25%) experiencing HE. Forty-four (22%) showed the spot sign, 69 (34.5%) the hypodensity sign, and 14 (7%) co-localized both as the Black-&-White sign. Those with the Black-&-White sign had higher proportions of HE (100% vs 19.4%, p < 0.001), greater absolute hematoma growth (23.37 mL (IQR = 15.41-30.27) vs 0 mL (IQR = 0-2.39), p < 0.001) and relative hematoma growth (120% (IQR = 49-192) vs 0% (0-15%), p < 0.001). The Black-&-White sign had a specificity of 100% (95%CI = 97.6%-100%), a positive predictive value of 100% (95%CI = 76.8%-100%), and an overall accuracy of 82% (95%CI = 76%-87.1%). Among the 14 patients with the Black-&-White sign, 13 showed an absolute hematoma growth ⩾12 mL, and 10 experienced a HE exceeding 75% of the initial volume. The inter-rater agreement was excellent (kappa coefficient = 0.84). CONCLUSION: The Black-&-White sign is a robust predictor of hematoma expansion occurrence and severity, yet further validation is needed to confirm these compelling findings.
ABSTRACT
The cloud responses to global warming are captured in various global climate models with distinct inferences on changes in cloud vertical structure as function of surface warming. However, long term observational evidences are scarce to validate the model outputs. Here, we have studied the changes in radiosonde derived cloud macro-physical properties and their association with other atmospheric variables during the period 2000-2019 in response to warming climate over the Indian summer monsoon region. We have observed a statistically significant increase in the frequency of cloudy days (â¼13 % decade-1), high-level clouds (HLCs â¼11 % decade-1) and simultaneous decrease in low-level clouds (LLCs â¼8 % decade-1) over the Indian region during the monsoon season. The multiple linear regression, principle component analyses and further correlation analyses suggest significant associations between cloud vertical structure variations and large-scale climate indicators, such as global warming and El Niño-Southern Oscillation. The vertical extension of the tropospheric column and the upward shift of clouds, attributed to global warming, explain the changes observed in both HLCs and LLCs. These results contribute to a deeper understanding of the dynamic interplay between global climate change and regional cloud dynamics, with implications for weather and climate modeling.
ABSTRACT
BACKGROUND AND PURPOSE: The presence of spot sign is associated with a high risk of hematoma growth. Our aim was to investigate the timing of the appearance, volume, and leakage rate of the spot sign for predicting hematoma growth in acute intracerebral hemorrhage using multiphase CTA. MATERIALS AND METHODS: In this single-center retrospective study, multiphase CTA in 3 phases was performed in acute intracerebral hemorrhage (defined as intraparenchymal ± intraventricular hemorrhages). Phases of the spot sign first appearance, spot sign volumes (microliter), and leakage rates among phases (microliter/second) were measured. Associations between baseline clinical and imaging variables including spot sign volume parameters (volume and leakage rate divided by median) and hematoma growth (>6 mL) were investigated using regression models. Receiver operating characteristic analysis was used as appropriate. RESULTS: Two hundred seventeen patients (131 men; median age, 70 years) were included. The spot sign was detected in 21.7%, 30.0%, and 29.0% in the first, second, and third phases, respectively, with median volumes of 19.7, 31.4, and 34.8 µl in these phases. Hematoma growth was seen in 44 patients (20.3%). By means of modeling, the following variables, namely the spot sign appearing in the first phase, first phase spot sign volume, spot sign appearing in the second or third phase, and spot sign positive and negative leakage rates, were associated with hematoma growth. Among patients with a spot sign, the absolute leakage rate accounting for both positive and negative leakage rates was also associated with hematoma growth (per 1-µl/s increase; OR, 1.26; 95% CI, 1.04-1.52). Other hematoma growth predictors were stroke history, baseline NIHSS score, onset-to-imaging time, and baseline hematoma volume (all P values < .05). CONCLUSIONS: The timing of the appearance of the spot sign, volume, and leakage rate were all associated with hematoma growth. Development of automated software to generate these spot sign volumetric parameters would be an important next step to maximize the potential of temporal intracerebral hemorrhage imaging such as multiphase CTA for identifying those most at risk of hematoma growth.