Single‐Frequency Birdcage Coils for Deep Tissue Perfluorocarbon Magnetic Resonance Imaging in Mice
Bibliographic record
Abstract
ABSTRACT Fluorine‐19 ( 19 F) MRI has become an established tool for in vivo cell tracking following ex vivo or in vivo labelling of various cell types with 19 F perfluorocarbons (PFCs). Here, we developed and evaluated novel mouse‐specific radiofrequency (RF) hardware for improved dual 1 H anatomical imaging and deep tissue 19 F MR detection of PFCs. Three linearly polarized birdcage RF coils were constructed—a dual‐frequency 1 H/ 19 F coil, and a pair of single‐frequency 1 H and 19 F coils, designed to be used sequentially. RF coil quality factors ( Q values ), signal homogeneity and sensitivity were benchmarked against a commercially constructed dual‐frequency 1 H/ 19 F surface coil. RF homogeneity was assessed using a phantom designed to mimic PFC localization at depth in a mouse. The single‐frequency birdcage coils ( 1 H and 19 F) displayed more uniform coverage and enhanced signal‐to‐noise ratios (SNRs) compared to both the birdcage and surface dual‐frequency coils for 19 F detection. Bilateral injection of a perfluoropolyether nanoemulsion into the footpads of female athymic nude mice, resulting in drainage to various lymph nodes and subsequent accumulation in lymph node macrophages, provided a platform to assess differences in SNRs and contrast‐to‐noise ratios (CNR) between both coil configurations as a function of depth and location. The single‐frequency 1 H coil provided significantly increased CNR in anatomical images ( p < 0.001) with increased anatomical coverage compared to the dual‐frequency surface coil. The single‐frequency 19 F birdcage coil offered increased PFC detectability with significantly higher SNR in renal, lumbar, sciatic and popliteal lymph nodes ( p < 0.01) compared to the dual‐frequency surface coil. Interestingly, the percentage difference between SNR measurements in lymph nodes between the single‐frequency 19 F coil and the 1 H/ 19 F surface coil had a linear relationship with increasing distance from the surface coil ( R 2 = 0.6352; p < 0.0001), indicating a potential disagreement for imaging experiments that rely on 19 F spin quantification at increasing depth within the mouse using surface RF coils.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".