Pediatric — Reference values: Pylorus — muscle thickness (HPS), Pylorus — canal length (HPS), Pylorus — diameter (HPS), Appendix — outer diameter.
| Measurement | Usual value | Note |
|---|---|---|
| Pylorus — muscle thickness (HPS) | > 3 mm | small infants may have HPS with lower valuesSource: Medscape / Permanente J |
| Pylorus — canal length (HPS) | ≥ 14–16 mm | Source: Medscape |
| Pylorus — diameter (HPS) | > 12 mm | Source: Medscape |
| Appendix — outer diameter | ≤ 6 mm | ≥ 6 mm and non-compressible = appendicitis (peds ~≥ 6.5 mm)✓ applied automatically in the reportSource: Radiology / StatPearls |
| Measure | Cutoff | Reading |
|---|---|---|
| Muscle thickness | ≥ 3 mm | Main criterion (≥2.5 mm in preterm/<3 weeks). |
| Channel length | ≥ 15–17 mm | Supports the diagnosis. |
| Pyloric diameter | ≥ 13 mm | Supportive finding. |
| Functional | No relaxation | Observe 10–20 min in real time. |
Correlate with non-bilious projectile vomiting and hypochloremic alkalosis. Borderline measurements → reassess in real time and repeat.
Source: Hernanz-Schulman (Radiology) / ACR-SPR practice parameter
| Finding | Reading |
|---|---|
| Target <20 mm | Probably transient ileo-ileal; observe. |
| Target 20–25 mm | Indeterminate — reassess. |
| Target ≥25 mm (ileocolic) | Usually requires enema reduction. |
| No flow / trapped fluid / lead point | Ischemia or lower reduction success; caution. |
Reduction (hydrostatic/pneumatic enema) if the child is stable and without perforation/peritonitis; otherwise surgery. A pathologic lead point warrants workup.
Source: ACR-SPR / Applegate (RadioGraphics)
| Type | Alpha angle | Interpretation |
|---|---|---|
| I | ≥ 60° | Normal/mature |
| IIa | 50–59° | Physiologically immature (< 3 months) |
| IIb | 50–59° | Delayed ossification (> 3 months) |
| IIc | 43–49° | Dysplastic |
| III–IV | < 43° | Eccentric / dislocated |
Also assess the beta angle and femoral head coverage.
Source: Graf method / Radiology Assistant