Tailoring an MRI for Children: Why Coil Size Matters

Magnetic Resonance Imaging (MRI) is widely used in pediatrics because it offers excellent soft-tissue contrast, no ionizing radiation, and the ability to capture functional as well as structural information. But unlike adult imaging, pediatric MRI presents unique challenges. Children’s smaller bodies, greater motion, and discomfort during long or poorly fitted exams can degrade image quality or even render scans non-diagnostic. Size and comfort in coil design are not luxury features they are clinical necessities.

Adult coil design vs. pediatric needs

Conventional adult coils are typically rigid and designed for the geometry of adult torso, head, or extremities. Because of their bulk and curvature, when applied to pediatric patients there is often a substantial air gap between the radiofrequency (RF) coil elements and the body surface. Increased coil-to-tissue distance significantly reduces signal-to-noise ratio (SNR), particularly at the periphery of the field of view, leading to non-uniform signal intensity and reduced diagnostic confidence. Vasanawala et al., Magn Reson Med; Roemer et al., Magn Reson Med

Poor fit also impairs parallel imaging performance. Parallel imaging and compressed sensing rely on distinct coil sensitivity profiles; if coils are too far from the anatomy or poorly conformed, acceleration factors are limited and reconstruction artifacts increase (Griswold et al., Magn Reson Med).

Additionally, rigid coils constrain positioning young children may need to be immobilized in uncomfortable or non-neutral postures to achieve adequate coverage, which increases the likelihood of motion during acquisition. Motion is a leading cause of nondiagnostic pediatric MR studies and a frequent driver of sedation or repeat imaging (Thukral et al., Pediatr Radiol).

By contrast, pediatric anatomy varies substantially by age. For example, head circumference increases nearly 50% between birth and 2 years, while thoracic and abdominal diameters expand at different rates throughout childhood

By contrast, pediatric anatomy varies substantially by age. For example, head circumference increases nearly 50% between birth and 2 years, while thoracic and abdominal diameters expand at different rates throughout childhood (CDC Growth Charts).

Designing coils that can adapt across this growth spectrum is therefore critical. Optimal pediatric coils provide a snug yet safe fit, minimize weight and bulk, and conform closely to body contours. This design improves SNR, enhances acceleration capability, and reduces the need for sedation by improving comfort and minimizing motion (Vasanawala et al., arXiv preprint; Liao et al., Sci Transl Med).

Motion artifacts

Children are inherently more prone to motion during scans due to discomfort, anxiety, and inability to remain still for long sequences. Even small displacements cause ghosting, blurring, and k-space inconsistencies that reduce diagnostic confidence or render images unusable.

In a prospective study of 82 pediatric patients (mean age 13.4 years), greater motion displacement and shorter “motion-free” scan intervals strongly correlated with non-diagnostic outcomes on T1 brain imaging (Thukral et al., Pediatr Radiol). Importantly, rigid or oversized coils that force awkward positioning can exacerbate this problem by making children less comfortable and more restless.

Repeat scans and diagnostic failure

Low SNR or motion-degraded studies often necessitate repeating sequences or, in some cases, entire exams. This compounds scan duration, raises cost, increases stress for families, and often triggers the use of sedation or general anesthesia to achieve diagnostic quality.

A review in Pediatric Radiology emphasized that long acquisition times are a key driver of motion-degraded, non-diagnostic studies, which in turn increase sedation requirements. The authors conclude bluntly: “faster is better” when it comes to pediatric MRI (Miller et al., Pediatr Radiol).

InkSpace Imaging’s Flexible Pediatric Coil: Built for Fit, Signal, and Comfort

Snuggle, InkSpace Imaging’s flexible pediatric coil is designed specifically for the pediatric

growth spectrum, integrating hardware and workflow considerations to overcome the limitations of adult-sized rigid coils.

Conformal geometry for optimized coil-to-tissue coupling

The azing coil–tissue distance (air gap), which is a primary determinant of signal-to-noise ratio (SNR). Improved coupling enhances peripheral SNR and uniformity, reducing the risk of missed lesions in smaller or off-axis structures. This design aligns with published work showing that coil proximity strongly impacts SNR and diagnostic accuracy in children (Roemer et al., Magn Reson Med; Vasanawala et al., arXiv).

Ergonomics and motion reduction

The pediatric coil’s lightweight, low-profile construction reduces patient discomfort and anxiety. Greater comfort decreases voluntary and involuntary motion, which is the single greatest contributor to nondiagnostic pediatric MRI scans (Thukral et al., Pediatr Radiol). Less motion translates into fewer artifacts, higher diagnostic confidence, and reduced sedation requirements.

Adaptive channel density (24–48 channel configurations)

The coil offers flexible channel counts, supporting both 24- and 48-channel configurations. This scalability allows optimization for parallel imaging and compressed sensing across varying pediatric body sizes. Higher channel density improves spatial encoding, enabling greater acceleration factors without unacceptable g-factor noise amplification (Griswold et al., Magn Reson Med). For clinicians, this means shorter scan times with preserved or even enhanced image quality.

Reliability and fewer repeat scans

By combining conformal fit with high channel density, the coil minimizes motion-induced signal loss and supports consistent image quality across sessions. This reduces the need for repeat sequences, shortening exam duration, decreasing sedation exposure, and lowering operational costs. When paired with abbreviated or accelerated protocols, the InkSpace pediatric coil enables clinically diagnostic imaging in significantly less time, echoing the findings of recent pediatric MRI acceleration studies (Miller et al., Pediatr Radiol).

This scalability allows optimization for parallel imaging and compressed sensing across varying pediatric body sizes. Higher channel density improves spatial encoding, enabling greater acceleration factors without unacceptable g-factor noise amplification (Griswold et al., Magn Reson Med). For clinicians, this means shorter scan times with preserved or even enhanced image quality.

Clinical benefits and safety implications

When pediatric coil design is optimized for fit, comfort, and channel geometry, downstream effects are measurable across safety, efficiency, and diagnostic quality:

• Reduced sedation / anesthesia needs.  Shorter, accelerated or abbreviated protocols materially lower the need for sedation/GA in pediatrics; multi-center reviews and institutional projects show significant reductions when scan time and motion are controlled. Examples include body MRI using accelerated/abbreviated protocols (chest, cardiovascular, abdomen) and awake MRI programs with audiovisual distraction (AVD) that achieved ≥20% relative reductions in minimal/moderate sedation among children 4–18 years while maintaining diagnostic quality and on-time completion.

• Lower risk of complications.  Although serious events are uncommon, pediatric MRI sedation is associated with respiratory and cardiovascular adverse events and sedation failures; reducing exposure is therefore a direct safety gain. A Pediatric Radiology minisymposium details safety challenges and advantages of non-sedated MRI pathways, and audit data highlight hypoxemia and other peri-sedation risks (even if infrequent).

• Improved scan efficiency.  Faster protocols and fewer repeats translate to shorter table time and better scanner throughput. Quality-improvement programs implementing awake MRI with AVD report on-schedule completion and sustained diagnostic quality; reviews conclude that “faster is better” in pediatric MRI because long acquisitions drive motion and non-diagnostic scans that consume additional time.

• Better diagnostic confidence (higher SNR, fewer artifacts).  Coil-to-tissue proximity is a primary determinant of SNR; distance and poor conformity degrade peripheral SNR and uniformity, which can obscure subtle findings. Classic and contemporary engineering studies describe how array design and shielding influence B1 homogeneity and SNR, while pediatric motion studies show that even small displacements correlate strongly with non-diagnostic outcomes on brain MRI. Optimizing fit/comfort reduces motion, preserves SNR, and stabilizes parallel-imaging performance improving confidence at the periphery and in small structures.

• Reinforced by non-pharmacologic pathways.  Systematic pediatric literature supports non-pharmacologic interventions (mock scanner, preparatory media, AVD, child-life) as standard components to reduce sedation/GA utilization synergistic with better hardware and accelerated protocols.

The Wrap Up

In pediatric MRI, size and comfort are not optional they are clinical imperatives. Poorly fitted, rigid coils degrade signal, amplify motion artifacts, and increase the need for repeat scans or sedation. Flexible, anatomically conforming coils with high channel density directly mitigate these risks.

Snuggle™, InkSpace Imaging’s pediatric coil, is the only purpose-built pediatric coil on the market. By improving SNR, reducing motion, and enabling accelerated protocols, it ensures children receive high-quality imaging with fewer risks and greater comfort. For radiologists and imaging leaders, prioritizing fit and comfort isn’t just about workflow it’s about delivering safer, more reliable care.

To learn more, reach out to our team here.