Multianimal Magnetic Resonance Imaging for Tumor Measurements in Pancreatic Cancer Mouse Models
February 3rd, 2026
This protocol uses a multichamber bed for parallel magnetic resonance imaging (MRI) of up to four animals to detect pancreatic adenocarcinoma tumors in genetically engineered mouse models. This multianimal MRI protocol is fast and cost-effective for detecting and measuring tumors, facilitating animal selection for preclinical studies and longitudinal monitoring of tumor growth.
Pancreatic ductal adenocarcinoma is a highly lethal disease. PDAC is usually diagnosed at later stages with locally advanced or metastatic disease, making it even more difficult to treat. PDAC is a heterogeneous disease characterized by highly aggressive cancer cells, extensive desmoplastic reaction, and hypovascularity.
KRAS-driven, genetically engineered mouse models are well suited for preclinical therapeutic evaluation as the carry mutation similar to human pancreatic cells and spontaneously develop pancreatic tumors with pathophysiology and molecular features resembling those of human PDAC. The KRAS-driven P53 deleted KPC model is a well-characterized PDAC genetically engineered mouse model. To effectively monitor tumor development and assess treatment responses in the KPC model, advanced in-vivo imaging modalities, such as magnetic resonance imaging are essential research tools.
MRI is widely considered to be the gold standard imaging modality for deep tumor evaluation, exhibiting the highest degree of soft tissue anatomical contrast and molecular sensitivity for deep tissue targets. However, standard MRI protocols incur high operational cost and long accusation times. This protocol uses a multi-animal chamber for parallel magnetic resonance imaging of up to four mice for detecting pancreatic adenocarcinoma tumors as a fast, economic, and precise method for tumor detection and measurement for preclinical trial, animal recruitment, and monitoring of treatment response.
Briefly, we begin by preparing the animal for the procedure and setting up the multi-animal MRI bed with our 3D printed inserts. Then we proceed with the MRI scanning, followed by data analysis to determine the success of the treatment for preclinical trials. Transport experimental KPC mice from the animal facility to the imaging facility.
Anesthetize up to four mice in a pretty warm sealed induction chamber with isoflurane. Apply ophthalmic lubricant to both eyes of each mouse to prevent corneal desiccation. Place two anesthetized mice in a ventral position on the bottom part of the 3D printed bed insert, which is attached to the vendor-provided standard single rat PET MRI scan holder.
Secure the head and a nose cone to maintain anesthesia. When scanning treated mice, place a protective barrier to prevent the potential transfer of chemotherapeutic agents through excretions. Cover the bottom with the top of the 3D-printed bed inserts.
Place another two anesthetized mice in a ventral position on the top part of the 3D printed bed insert. Secure the head in a nose cone to maintain anesthesia. The vendor-provided single rat PET MRI bed is equipped with circulating warm air to maintain body temperature of the animals.
Attach the respiratory monitor to the one mouse positioned on the left side of the top 3D bed insert. Cover the bed to complete multi-animal MRI chamber. Ensure the mice will be located in the center of the MRI coil by aligning the red laser with the center of the mice.
Assign a label to the scan using the mouse ID and scan date in the following format. Strain, mouse ID, scan date. Acquire a localizer image to define the appropriate imaging area for all four mice positioned in the bed.
The localizer scan is a T1 weighted flash scan with one axial slice, two coronal slices, and two sagittal slices to visualize the mice in the four mouse bed. To set up the T2 rare scan, adjust the slice packages based on the localizer image as needed to optimize visualization of the pancreas region and other abdominal organs for the top and bottom set of animals. Confirm that all four mice are correctly aligned in the multi-animal bed setup before proceeding with the scanning.
Monitor respiration throughout the imaging sequences and adjust isoflurane level if necessary. When the scan is completed, remove the bed from the MRI. Open the top of the multi-animal bed and remove the respiratory monitor from the top left mouse.
Transfer animals from the top and bottom of the 3D printed inserts into the recovery cage. Place the recovery cage over a 42 degrees Celsius heating pad for post anesthesia recovery. Monitor respiratory rate and movement to ensure full recovery from anesthesia before returning mice to home cages.
Export the DICOM images from ParaVision 360 to an image analysis program to crop the images from one image with four mice to one image for each individual mouse. In PMOD, open the image for the top set of animals in the View module. In the VOI tab, draw a box around the top right mouse, then crop the image around that box.
Edit the DICOM metadata to the correct mouse id, then save the crafted image with the correct file name. Repeat for the top left mouse using the same image, then open the image for the bottom set of mice and repeat the cropping and saving. Use MRI viewer software to analyze images stored in DICOM files.
We use Open Source MRI Viewer for our software package. Analyze imaging slices from dorsal to ventral or ventral to dorsal. Locate organs like spleen and stomach for proper localization of the pancreas and pancreatic tumors.
Define region of interest in all slices where tumor is present and perform semi-automated segmentation to calculate tumor volume. Take note of fluid cysts, and other hyperchromatic symptoms. In representative MRI image, we can detect the stomach, spleen, and tumor.
Most KPC tumors showed a solid growth pattern with single or predominant focus, which facilitated recruitment for treatments and tumor volume assessment. However, we also observed animals with multiple small solid tumors spread throughout the entire pancreas. PDAC tumors may also demonstrate intratumoral cystic appearance accompanied by paratumoral, non-neoplastic cystic lesions or ductal blockage, which can result in fluid containing lesions.
Correlative tissue studies show concordance between anatomical tumor feature by MRI and histological feature of H&E stain tumor tissues collected immediately after imaging session. Hyperchromatic region on MRI consistent with fluid-filled lesion corresponds to cystic lesion and histological analysis. We use this multi-animal MRI for monitoring pancreatic tumor progression in the KPC model treated with chemotherapeutic agent gemcitabine as a proof of concept preclinical trial.
Gemcitabine alone or in combination is the first line treatment for patients with local or metastatic pancreatic cancer. KPC animals develop pancreatic tumors after 12 weeks of age. Following recruitment, animals were designated into two experimental groups.
One, receiving intraperitoneal administration of gemcitabine and a control group without any treatment. Weekly MRI scans were conducted using the multi-animal bed system, which enabled us to continuously monitor the changes in tumor growth kinetics in both the treatment and control groups. Our data demonstrates that tumors in the gemcitabine-treated KPC model had a slower growth pattern compared to untreated control group.
A result with gemcitabine treated animals are consistent with previous reports and conferring a survival benefit. This protocol provides a suitable and robust platform to study combination therapies of new therapeutic agents in standard of care chemotherapy. We are using this cost-effective MRI protocol to investigate the role of specific mRNAs and PDAC with complementary genetic and pharmacological approaches.
But these combination therapies may also be small molecule inhibitors, immunotherapy, siRNAs, and other therapeutic oligonucleotides against key molecular targets. While the focus of this protocol is the imaging of the pancreas and other abdominal cavity organs, this multi-animal protocol and described MRI sequences can be applied for anatomical characterization of other mouse models of cancer, such as breast cancer and glioblastoma or other diseases involving the kidney and or liver. Overall, this multi-animal MRI protocol offers a fast, reliable, and cost effective platform for high-quality, longitudinal tumor monitoring and preclinical therapeutic evaluation in pancreatic cancer models.
Overview
This protocol describes a multichamber bed for parallel magnetic resonance imaging (MRI) of up to four animals, aimed at detecting pancreatic adenocarcinoma tumors in genetically engineered mouse models. This approach is efficient and cost-effective for tumor detection and monitoring in preclinical studies.
Key Study Components
Area of Science
- Neuroscience
- Oncology
- Imaging Techniques
Background
- Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer often diagnosed at advanced stages.
- Genetically engineered mouse models, particularly KRAS-driven models, are valuable for preclinical therapeutic evaluation.
- Advanced imaging modalities like MRI are essential for monitoring tumor development and treatment responses.
- Standard MRI protocols can be costly and time-consuming.
Purpose of Study
- To establish a multichamber MRI protocol for efficient detection of pancreatic tumors in mice.
- To facilitate animal selection for preclinical trials and monitor tumor growth longitudinally.
- To improve the cost-effectiveness and speed of MRI procedures in research settings.
Methods Used
- Preparation of animals and setup of a multi-animal MRI bed with 3D printed inserts.
- Anesthesia of mice using isoflurane and monitoring during the imaging process.
- Acquisition of localizer images and T2 scans to visualize pancreatic tumors.
- Data analysis using DICOM images to assess tumor volume and characteristics.
Main Results
- The protocol allows for simultaneous imaging of up to four mice, enhancing throughput.
- Successful detection of tumors with high anatomical contrast and sensitivity.
- Identification of various tumor characteristics, including solid growth patterns and cystic appearances.
- Correlation between MRI findings and histological features of tumors.
Conclusions
- The multichamber MRI protocol is a valuable tool for preclinical studies of PDAC.
- This method improves efficiency in tumor detection and monitoring.
- Future applications may enhance therapeutic evaluation in pancreatic cancer research.
Frequently Asked Questions
Executive Industry Relevance
Efficient, high-throughput tumor measurement in preclinical models is critical for translational oncology pipelines, especially in aggressive diseases like pancreatic ductal adenocarcinoma. The multianimal MRI protocol enables robust, quantitative, and longitudinal tumor assessment in genetically engineered mouse models, directly supporting therapeutic hypothesis testing and treatment response evaluation. This scalable imaging workflow reduces operational barriers, accelerates preclinical decision-making, and enhances portfolio triage for novel and combination therapies.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables rigorous, noninvasive monitoring of tumor initiation and progression in disease-relevant models.
- Supports functional validation of molecular targets by correlating imaging findings with genetic and pharmacological interventions.
- Facilitates mechanistic de-risking by providing anatomical and volumetric tumor data aligned with histopathology.
- Improves predictive confidence for advancing candidate therapies in pancreatic cancer research.
Screening & Assay Development
- Prepares validated animal cohorts for downstream efficacy studies and compound screening.
- Standardizes tumor measurement protocols, ensuring reproducibility and quantitative comparability across studies.
- Enables scalable, parallel imaging to support higher-throughput preclinical screening workflows.
- Provides reliable, high-resolution anatomical data for robust compound evaluation and cohort selection.
Translational & Preclinical Research
- Aligns preclinical imaging outputs with clinical endpoints by using longitudinal, quantitative tumor volume measurements.
- Supports translational biomarker development through correlation of MRI features with histological and molecular data.
- Enables risk-adjusted advancement of therapeutic candidates based on objective, reproducible imaging criteria.
- Facilitates continuity from discovery through preclinical validation in disease-relevant systems.
Pipeline & Workflow Integration
This multianimal MRI protocol integrates into the preclinical discovery-to-lead identification continuum, supporting both early target validation and late-stage efficacy assessment in oncology pipelines.
- Discovery Biology: Provides quantitative, noninvasive tumor monitoring to test therapeutic hypotheses and clarify disease mechanisms.
- Screening: Delivers standardized, reproducible imaging outputs for cohort selection and compound evaluation.
- Analytics: Generates volumetric and anatomical readouts that enable statistical comparison of treatment groups.
- Translational Research: Bridges preclinical imaging with clinical relevance by aligning imaging and histopathological findings.
- Enterprise Reuse: Offers a reusable imaging platform adaptable to other cancer and disease models beyond pancreatic cancer.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in preclinical oncology studies.
- Operational Value: Enhances throughput, standardization, and cost-efficiency in animal imaging workflows.
- Strategic Value: Enables more informed go/no-go decisions and optimizes resource allocation across therapeutic programs.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of candidate therapies based on robust imaging data.
Implementation Considerations
- Requires expertise in animal handling, MRI operation, and image analysis.
- Needs access to multianimal MRI hardware, anesthesia systems, and compatible analysis software.
- Demands cross-team standardization of imaging protocols and data management practices.
- Adaptable to various genetically engineered mouse models and potentially other disease indications.
- Imaging throughput and resolution may be limited by hardware and animal size constraints.
