PET/CT study suggests splenic cutoff values in canine lymphoma
Bottom line
A new study in Veterinary Radiology & Ultrasound suggests fluorine-18 fluorodeoxyglucose PET/CT could help identify splenic dissemination in dogs with lymphoma using quantitative imaging markers rather than invasive sampling alone. In an abstract presented through the American College of Veterinary Radiology, researchers from Colorado State University and collaborators reported that dogs with splenic lymphoma involvement had higher splenic SUVmax, metabolic tumor volume, and total lesion glycolysis than dogs with benign splenic cytology. The team identified statistically significant cutoff values for SUVmax greater than 3.55 and MTV greater than 325.7 at a 1.5 SUV threshold, based on serial PET/CT scans performed before, during, and after CHOP chemotherapy. (acvr-website.s3.amazonaws.com)
Why it matters: For veterinary professionals, the finding points toward a more standardized, noninvasive way to stage and monitor canine lymphoma, especially in cases where splenic involvement can be difficult to confirm or track over time. That could be useful because PET/CT has already shown promise for detecting liver and spleen involvement and for following treatment response in dogs with lymphoma, but veterinary evidence has remained limited and access to the modality is still uneven. Normal canine spleens generally have low physiologic FDG uptake, which may make elevated splenic metabolic activity more clinically meaningful when interpreted alongside cytology and the rest of the staging workup. (onlinelibrary.wiley.com)
What to watch: The next question is whether these cutoff values hold up in larger cohorts and whether they can be integrated into routine response assessment and relapse monitoring protocols. (acvr-website.s3.amazonaws.com)
Key facts
- Study
- Canine lymphoma imaging study in Veterinary Radiology & Ultrasound
- Imaging method
- 18F-FDG PET/CT
- Population
- Dogs with lymphoma
- Comparison
- Splenic lymphoma involvement versus benign splenic cytology
- Key finding
- Dogs with splenic lymphoma had higher splenic SUVmax, metabolic tumor volume, and total lesion glycolysis
- Cutoff values
- SUVmax greater than 3.55 and MTV greater than 325.7 at a 1.5 SUV threshold
- Treatment context
- Serial scans were performed before, during, and after CHOP chemotherapy
- Potential use
- Noninvasive staging, therapeutic monitoring, and recurrence assessment
A newly published canine lymphoma imaging study is adding quantitative benchmarks to a tool many veterinary oncologists still view as promising but not yet routine. In Veterinary Radiology & Ultrasound, investigators reported that dogs with splenic dissemination of lymphoma had higher splenic SUVmax, metabolic tumor volume, and total lesion glycolysis on ^18F-FDG PET/CT than dogs whose splenic cytology was benign, suggesting these metrics may help identify splenic involvement noninvasively. (acvr-website.s3.amazonaws.com)
The work builds on a long-running interest in PET/CT for canine oncology. Earlier veterinary reports showed FDG-PET could detect lymphoma involvement in superficial and internal lymph nodes, liver, and spleen, and that abnormal uptake could resolve after induction chemotherapy. More recent reviews have described PET/CT as increasingly available in referral settings, but still constrained by cost, infrastructure, and a relatively small evidence base compared with human oncology. (onlinelibrary.wiley.com)
According to the ACVR proceedings abstract tied to the study, the investigators evaluated dogs diagnosed with lymphoma by lymph node aspirates that underwent serial ^18F-FDG PET/CT before, during, and after CHOP chemotherapy. They contoured the spleen at each imaging time point and compared splenic cytology with three PET-derived metabolic parameters: SUVmax, MTV, and TLG. The study found statistically significant cutoffs for SUVmax greater than 3.55 and MTV greater than 325.7 at a 1.5 SUV threshold, and also reported significantly higher mean or median splenic SUV, MTV, and TLG in dogs with splenic lymphoma compared with dogs with benign splenic cytology. The authors concluded those thresholds may support noninvasive staging, therapeutic monitoring, and recurrence assessment. (acvr-website.s3.amazonaws.com)
That matters because splenic staging in canine multicentric lymphoma has often been clinically relevant but not always management-changing in a straightforward way. Standard references note that liver and spleen involvement define stage IV disease, yet also point out that advanced imaging utility in typical canine multicentric lymphoma is still being worked out, particularly because prognostic differences between stage III and stage IV disease are not always clear in routine practice. A tool that can quantify splenic disease burden and track it longitudinally may therefore prove more valuable for response assessment and recurrence surveillance than for stage assignment alone. That’s an inference based on the study design and the broader literature, rather than a direct claim from the authors. (elsevier-elibrary.com)
There’s also a technical reason the spleen is an appealing target for this kind of work. Baseline physiologic FDG uptake in the normal canine spleen is reported as similar to or lower than aortic blood pool activity, which may help abnormal uptake stand out more clearly than in organs with higher background metabolism. Even so, PET interpretation is rarely simple in oncology, and prior veterinary and comparative literature has emphasized that inflammatory processes can also increase FDG uptake. That means cytology, clinical context, and serial imaging trends will still matter. (pubmed.ncbi.nlm.nih.gov)
Expert reaction specific to this paper was limited in publicly available sources, but the broader field has been moving toward more quantitative whole-body imaging in canine lymphoma. A 2026 proof-of-concept study on whole-body diffusion-weighted MRI similarly highlighted the appeal of noninvasive assessment of abdominal organ involvement and treatment response in multicentric high-grade lymphoma, underscoring that referral oncology is actively looking for better whole-body staging and monitoring tools beyond conventional imaging alone. (link.springer.com)
Why it matters: For veterinary professionals, this study pushes PET/CT a step closer to being a measurable decision-support tool rather than just an advanced imaging option. If validated, splenic SUVmax, MTV, and TLG thresholds could help standardize how referral teams interpret splenic uptake, reduce reliance on repeat invasive sampling in some cases, and provide a common language for monitoring remission, residual disease, or relapse. The practical limitation is that PET/CT remains concentrated in specialty settings, so near-term impact is likely to be greatest in academic centers, specialty hospitals, and comparative oncology programs rather than general practice. (acvr-website.s3.amazonaws.com)
What to watch: The key next steps are full peer-reviewed publication details beyond the abstract-level reporting, validation in larger and more diverse canine lymphoma cohorts, and evidence tying these PET metrics to outcomes such as progression-free survival, relapse detection, or changes in treatment planning. If those data emerge, quantitative splenic PET markers could become one of the more practical ways advanced imaging informs lymphoma management for pet parents and care teams. (acvr-website.s3.amazonaws.com)