SubtleHD-CT can now be marketed in the U.S. as an AI/ML software product for processing and enhancing CT images, according to FDA 510(k) records.
The FDA listed SubtleHD-CT as substantially equivalent on May 15, 2026, under product code QIH for automated radiological image processing software. The device is classified as a Class II radiology product.
FDA records state that SubtleHD-CT is intended for processing and enhancement of CT images regardless of the manufacturer or model of CT scanner.
The software is a post-processing SaMD product. FDA summary documents state that it does not directly interact with the scanner and processes CT images after acquisition through DICOM-based workflow infrastructure.
Enhanced images are sent back to PACS or another DICOM node for clinical review. FDA documents also state that interpretation of SubtleHD-CT output should be adjunctive to the original reconstructed image.
Subtle Medical said the software is designed to reduce noise and improve low-contrast detectability across CT imaging. The company said the product can integrate into existing workflows without requiring new scanner hardware.
The FDA summary lists ClariCT.AI from Claripi as the primary predicate device. SubtleHD-CT uses a convolutional neural network for image enhancement, according to the 510(k) summary.
Validation included software verification and validation testing, phantom testing with ACR Phantom, Digital CatPhan Phantom and Mercury 4.0 Phantom, and a reader study using retrospective clinical data. The FDA summary states that those tests passed.
The reader-study dataset included abdomen, C-spine, cardiac, chest, chest-abdomen-pelvis, head, head and neck, L-spine, lower-extremity, MSK, T-spine and upper-extremity CT exams. Scanner vendors included Canon, GE Medical Systems, Hitachi, Philips and Siemens.
Subtle Medical described SubtleHD-CT as its first CT product and its 11th FDA-cleared product overall. The company said its broader AI image-enhancement portfolio is deployed across more than 1,300 scanners worldwide.
Company:Subtle Medical
Sources
- 510(k) Premarket Notification K254120. Government document
- K254120 510(k) Summary. Regulatory filing
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