Automated Cerebral Hemorrhage Detection Using RAPID

Abstract

Background and purpose: Intracranial hemorrhage (ICH) is an important event that is diagnosed on head NCCT. Increased NCCT utilization in busy hospitals may limit timely identification of ICH. RAPID ICH is an automated hybrid 2D-3D convolutional neural network application designed to detect ICH that may allow for expedited ICH diagnosis. We determined the accuracy of RAPID ICH for ICH detection and ICH volumetric quantification on NCCT.

Materials and methods: NCCT scans were evaluated for ICH by RAPID ICH. Consensus detection of ICH by 3 neuroradiology experts was used as the criterion standard for RAPID ICH comparison. ICH volume was also automatically determined by RAPID ICH in patients with intraparenchymal or intraventricular hemorrhage and compared with manually segmented ICH volumes by a single neuroradiology expert. ICH detection accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and positive and negative likelihood ratios by RAPID ICH were determined.

Results: We included 308 studies. RAPID ICH correctly identified 151/158 ICH cases and 143/150 ICH-negative cases, which resulted in high sensitivity (0.956, CI: 0.911-0.978), specificity (0.953, CI: 0.907-0.977), positive predictive value (0.956, CI: 0.911-0.978), and negative predictive value (0.953, CI: 0.907-0.977) for ICH detection. The positive likelihood ratio (20.479, CI 9.928-42.245) and negative likelihood ratio (0.046, CI 0.023-0.096) for ICH detection were similarly favorable. RAPID ICH volumetric quantification for intraparenchymal and intraventricular hemorrhages strongly correlated with expert manual segmentation (correlation coefficient r = 0.983); the median absolute error was 3 mL.

Conclusions: RAPID ICH is highly accurate in the detection of ICH and in the volumetric quantification of intraparenchymal and intraventricular hemorrhages.

FIG 1.

Representative imaging examples of ICH correctly detected by RAPID. A. Primary intraparenchymal hemorrhage within the right thalamus and posterior limb of the right internal capsule (red outline by RAPID). B. Small extra-axial subdural hematoma overlying the right cerebral hemisphere (red outline by RAPID). C. Subarachnoid hemorrhage (red outline by RAPID). D. Subarachnoid and intraventricular (right and left lateral, third, and fourth ventricles) hemorrhage (red outline by RAPID).

FIG 2.

Representative false-positive and false-negative ICH examples. A. RAPID incorrectly detected ICH (false-positive result) in a patient with volume averaging in the anterior cranial fossa and beam-hardening artifact in the posterior fossa (red outlines by RAPID). B. RAPID failed to detect ICH (false-negative result) in a patient intraparenchymal hemorrhage in the left thalamus (yellow arrow). C. RAPID failed to detect ICH (false-negative result) in a patient with a small amount of subarachnoid and intraventricular hemorrhage (yellow arrows).

FIG 3.

Intraparenchymal and intraventricular hemorrhage volumetric agreement between RAPID and expert interpretation. A and B, Representative example of an intraparenchymal hemorrhage in the right basal ganglia. Manual segmentation by a neuroradiologist (A, green outline) is well correlated with automated segmentation by RAPID ICH (B, red outline). C. Scatterplot denotes volumetric agreement between RAPID and expert evaluation for NCCT with isolated intraparenchymal or intraventricular hemorrhage.