4DMedical’s CT:VQ clearance could mark the end of nuclear VQ scans—is the industry ready for software-first lung imaging?

What makes CT:VQ different—and why FDA clearance may signal the beginning of a diagnostic shift

When 4DMedical Limited (ASX:4DX) secured FDA 510(k) clearance for its CT:VQ lung imaging software in September 2025, it wasn’t just a regulatory win—it may have marked the beginning of the end for a long-standing diagnostic workflow. For decades, ventilation-perfusion (VQ) imaging has relied on nuclear medicine. Patients have had to inhale radioactive tracers, undergo intravenous injection, and wait for gamma cameras to piece together a clinical picture. With CT:VQ, 4DMedical has introduced a software-only alternative that generates quantitative VQ maps from routine chest CT scans, using no contrast agents and no radiotracers.

This is the world’s first and only platform to achieve such clearance, and the implications are profound. CT:VQ eliminates many of the logistical bottlenecks that currently plague traditional VQ imaging—scheduling conflicts, regulatory hurdles around radioactive material, and the limited availability of nuclear medicine equipment outside major hospitals. With more than 14,500 CT scanners already installed in U.S. healthcare facilities, including in rural areas, the foundation for rapid deployment is already in place.

At its core, CT:VQ analyzes subtle lung tissue motion and density variations during the respiratory cycle. This allows it to derive both ventilation and perfusion maps from a single standard CT scan, completed in a matter of minutes. The workflow is plug-and-play—no special radiopharmaceuticals, no additional infrastructure, and no procedural delays. And with over one million nuclear VQ scans performed annually in the U.S. alone, 4DMedical is entering a USD $1.1 billion market at the exact moment the medical imaging sector is hungry for cost-effective, high-throughput, and minimally invasive alternatives.

Why nuclear medicine may be at a crossroads—and how 4DMedical could accelerate the pivot to SaaS imaging

Nuclear VQ imaging has been a mainstay for pulmonary embolism diagnosis and preoperative lung assessment. But it’s also one of the most infrastructure-dependent diagnostic procedures, with workflows built around radioactive tracers, specialist oversight, and long scan times. CT:VQ offers an entirely new pathway—one that lowers radiation exposure, reduces procedural complexity, and significantly expands access.

From a healthcare operations standpoint, this shift could be transformative. CT:VQ enables hospitals to extract more clinical value from the CT hardware they already have. It also allows for faster throughput of patients and eliminates many of the restrictions tied to radioactive material handling. For overburdened radiology departments and budget-conscious hospitals, this makes CT:VQ more than a clinical tool—it’s an efficiency play.

The clearance also arrives at a time when AI and software-based diagnostics are finally being integrated into standard-of-care protocols. While many imaging AI companies are focused on triage and anomaly detection, 4DMedical is pushing the frontier of functional imaging—quantifying organ-level physiology rather than just flagging suspicious pixels. That elevates CT:VQ from a decision-support tool to a true diagnostic replacement candidate.

Clinical validation played a major role in the FDA’s approval. 4DMedical conducted direct performance comparisons with SPECT scans and consistently demonstrated diagnostic equivalence across key pulmonary conditions. Radiologists and lung specialists reported high concordance between CT:VQ and traditional nuclear imaging, with the added benefit of higher-resolution images and fewer artefacts. These findings were supported by real-world case data presented at the 2025 American Thoracic Society meeting, and further bolstered by research deployments at Stanford University and the U.S. Department of Defense’s Brooke Army Medical Center.

Will hospitals, payers, and radiologists embrace a software-first standard for lung diagnostics?

Despite the compelling case, the big question remains: will CT:VQ see adoption at the scale that justifies its disruption potential? Hospitals are notoriously conservative when it comes to replacing entrenched clinical workflows—especially those with well-established reimbursement codes and procedural familiarity. Nuclear VQ imaging, while cumbersome, is a known quantity.

But the winds may be shifting. CT:VQ is not asking hospitals to replace equipment. It’s offering them a way to do more with the equipment they already have. From a payer perspective, the cost-efficiency argument is strong. Each nuclear VQ scan costs approximately USD $1,150. If CT:VQ can achieve billing parity or even modest reimbursement at volume, it could undercut nuclear medicine procedures while offering broader clinical value—especially in settings where repeat scanning is required.

There’s also the broader strategic narrative. Radiology is moving into its SaaS phase, and software-native diagnostics are no longer niche. CT:VQ integrates into PACS and RIS systems, plays well with hospital IT infrastructure, and can be offered under a subscription or pay-per-scan model. That gives hospitals cost predictability and scalability—two elements that procurement teams are increasingly prioritizing.

And then there’s the government channel. Through its partnership with Philips, 4DMedical has secured exclusive distribution rights for CT:VQ to U.S. federal health institutions, including the Department of Veterans Affairs and the Department of Defense. Philips has already trained more than 200 sales reps to promote the platform, and CT:VQ is now live in its product catalogue. For a software product to earn that kind of commercial backing and federal advocacy—Philips even referenced the technology in Congressional testimony—it speaks volumes about institutional readiness.

Why investors are revisiting 4DMedical’s platform potential in the post-clearance landscape

With CT:VQ now FDA-cleared and embedded into U.S. federal distribution pipelines, investor sentiment is shifting from speculative optimism to concrete platform valuation. This isn’t just a single-product story anymore. 4DMedical has built a growing suite of functional and structural imaging tools, including XV LVAS, IQ-UIP, LDAi, and SeleCT. The company reported 194,789 scans in FY2025—up more than 100% year-on-year—and now operates across 388 global sites. SaaS revenue rose 95%, and gross margins exceeded 90%, confirming the leverage inherent in the business model.

The Pro Medicus investment in FY2025, the cost-reduction program delivering AUD $6.5 million in annualised savings, and strong scan growth show that 4DMedical is moving decisively into its scale-up phase. As hospital contracts expand, distribution partnerships deepen, and real-world evidence builds, institutional investors are likely to re-rate 4DMedical as a commercial-stage SaaS platform rather than an R&D-heavy medtech startup.

For long-term investors, this raises a critical inflection point. CT:VQ is not just a new product—it’s a wedge into a diagnostic category ripe for reinvention. If hospitals begin to transition from radiotracers to code, 4DMedical could be remembered not for launching a feature, but for redefining an entire field.