Scoping Review of Literature on B-Mode Cranial Ultrasonography to Detect Intracranial Hemorrhage

Poster Title: Scoping Review of Literature on B-Mode Cranial Ultrasonography to Detect Intracranial Hemorrhage

Student: Beddome Allen, Class of 2021

Faculty Mentor and Department: Dr. Aarti Sarwal, Department of Neurology

Funding Source: None

ABSTRACT

Background: Transcranial color-coded sonography (TCCS) is a commonly used diagnostic modality for evaluating cerebrovascular pathology. B mode imaging is the initial step towards image acquisition, but parenchymal assessment using B mode has not been widely adopted. With emerging reports on point of care cranial ultrasound imaging of intracranial hemorrhage (ICH) in the critical care setting, we performed a scoping review of literature to evaluate the utility of cranial ultrasound B mode in ICH diagnosis.

Hypothesis: Cranial ultrasound is an accurate neuroimaging alternative for patients who do not have timely access to computed tomography (CT) and magnetic resonance imaging (MRI) in the detection of ICH in critically ill patients.

Methods: We conducted a literature search of PubMed, Embase, Cochrane, Web of Science, Scopus, and CINAHL databases to identify articles evaluating the use of ultrasound in ICH diagnosis compared to CT or MRI using a broad set of Medical Subject Headings. All pediatric and adult studies were included if they reported at least one measure of diagnostic accuracy. Exclusion criteria included neonatal studies, studies reporting only Doppler findings, post-mortem studies, animal studies, and studies that lacked corroborating CT or MRI. Measures of diagnostic accuracy and ultrasound settings were extracted.

Results: We identified 18 studies meeting criteria (17 adult, 1 pediatric) conducted between January 1990 and July 2021. The diagnostic accuracy of cranial US in identifying ICH compared to CT or MRI varied between 78% and 100% in thirteen studies. Six studies reported sensitivities ranging from 46.7% to 100%. Four studies reported specificities with ranges from 92.9% to 100%. Small vessel disease and micro-hemorrhages were the most often reported false positive findings. The correlation coefficient between cranial ultrasound-derived and CT-derived ICH volume ranged from 0.4 to 0.981. Regarding ultrasound settings, seven studies provided the insonation depth, one study provided the mechanical index, and no papers reported the power or gain parameters. No studies reported the ultrasound presets used. 

Conclusions: Cranial ultrasound may have reasonable accuracy in point of care ICH diagnosis, especially in austere environments or clinical scenarios where head CT is not accessible to a critically ill patient. Future studies should investigate cranial ultrasound parameters to identify clinically relevant presets that further enhance the diagnostic accuracy of ICH.

Source of mentor’s funding or other support that funded this research: None