Radiology References

Imaging atlases, normal values, and reporting templates.

302 references · Page 7 of 11

P

Normal PICC Line Position on Chest Radiography
Normal PICC line tip position on chest radiography is within the superior vena cava, confirmed to ensure safe central venous access.
Normal Pituitary Gland Diameter Size on MRI
Normal pituitary gland anteroposterior diameter on MRI is up to 6 mm in children under 12 and up to 10 mm at puberty.
Normal Pituitary Stalk Size on CT and MRI
Normal pituitary stalk diameter measures less than 2–5 mm on CT and MRI; values above this range suggest pathological thickening.
Normal Placenta Previa Distance Size on Ultrasound
Learn the normal placenta-to-os distance threshold for placenta previa on ultrasound, with clinical significance and measurement technique pearls.
Normal Popliteal Artery Diameter on Ultrasound, CT & MRI
Normal popliteal artery diameter ranges from 4.1–5.6 mm on axial imaging; learn measurement technique and clinical thresholds across ultrasound, CT, and MRI.
Normal Popliteal Artery Peak Systolic Velocity on Ultrasound
Normal popliteal artery peak systolic velocity on duplex ultrasound ranges from 55–82 cm/s, a key benchmark for diagnosing peripheral arterial disease.
Normal Portal Vein Diameter on Ultrasound
Reference values for normal portal vein diameter on ultrasound across all age groups, from neonates to adults, with clinical significance.
Normal Portal Vein Velocity on Ultrasound
Normal portal vein velocity on Doppler ultrasound ranges from 20–30 cm/s, a key metric for detecting portal hypertension and hepatic vascular disease.
Normal Posterior Cruciate Ligament Thickness on MRI
Normal posterior cruciate ligament thickness on MRI measures less than 6 mm; values above this threshold suggest PCL pathology requiring further evaluation.
Normal Posterior Junction Line Thickness on Radiography
The normal posterior junction line measures less than 1 mm on PA chest radiography; understanding this landmark helps detect mediastinal pathology early.
Normal Posterior Semicircular Canal Size on CT and MRI
Normal posterior semicircular canal average diameter is 1.5 mm on axial CT and MRI, a key reference for evaluating inner ear anomalies.
Normal Posterior Tracheal Wall Thickness on Radiography
Normal posterior tracheal wall thickness on lateral chest radiography measures less than 2.5 mm — a key landmark for detecting retrotracheal pathology.
Normal Powers Index Cervical Size: X-Ray, CT & MRI
The normal Powers Index is less than 1 on lateral imaging; values ≥1 indicate atlantooccipital dislocation on X-ray, CT, or MRI.
Normal Presacral Space Size on Barium Enema in Children
Normal presacral space measures less than 5 mm on barium enema in children aged 0–15 years; enlargement may indicate inflammatory or neoplastic pathology.
Normal Prevertebral Soft Tissue C2 Thickness Radiography CT
Reference values for normal prevertebral soft tissue maximal thickness at C2 in pediatric patients on lateral radiography and CT by age group.
Normal Prevertebral Soft Tissue Thickness on Radiography
Normal prevertebral soft tissue thickness values on lateral cervical radiography, from C1 to C7, based on Penning 1981 reference data.
Normal Prevertebral Soft Tissue Thickness on Radiography
Normal prevertebral soft tissue thickness in cervical spine flexion on lateral radiography, with average values from C1 to C7 per Penning 1981.
Normal Prevertebral Soft Tissue Thickness on Radiography
Normal prevertebral soft tissue thickness on lateral cervical radiography ranges from 3.2 mm at C2 to 15.1 mm at C6 in neutral position.
Normal Prevertebral Soft Tissue Thickness on X-Ray, CT & MRI
Reference values for normal prevertebral soft tissue thickness at C1–C7 on radiography, CT, and MRI, with clinical significance and measurement technique.
Normal Prostate Dimensions on Ultrasound
Normal prostate dimensions on ultrasound measure approximately 2.8 × 2.8 × 4.8 cm, with values above this threshold suggesting benign or malignant enlargement.
Normal Prostate Volume Size on Ultrasound
Normal prostate volume on ultrasound is up to 30 mL in adults; values above this threshold may indicate benign or malignant enlargement.
Normal Proximal Pulmonary Artery Diameter on CT and MRI
Normal proximal pulmonary artery diameter on CT and MRI: left 21 ± 3.5 mm, right 18.7 ± 2.8 mm, with key thresholds for pulmonary hypertension.
Normal Pseudosubluxation Size on Cervical Radiography
Normal pseudosubluxation at C2/C3 measures less than 3 mm on lateral cervical radiography, a critical threshold to distinguish physiologic from true subluxation.
Normal Pseudosubluxation Size on Cervical Spine Radiography
Normal cervical pseudosubluxation measures less than 3 mm at C3/C4 on lateral radiography, a key threshold for distinguishing physiologic from pathologic displacement.
Normal Pulmonary Artery Trunk Size on CT and MRI
Reference values for normal pulmonary artery trunk diameter on CT and MRI, including sex-specific averages and the upper limit of 28.6 mm.
Normal Pylorus Diameter & Thickness on Ultrasound
Normal pyloric muscle thickness is <3 mm and channel length <15 mm on ultrasound; values above these thresholds suggest hypertrophic pyloric stenosis.

Q

Normal Quadriceps Angle Size on X-ray, CT & MRI
Normal quadriceps (Q) angle of the knee measures 15–20° on radiography, CT, and MRI, with clinical relevance to patellar instability and tracking disorders.

R

Normal Radial Inclination Angle Size on Radiography
Normal radial inclination on posteroanterior wrist radiography measures 21–25°, a key parameter for assessing distal radius fractures and alignment.
Normal Radial Length Size on Wrist Radiography
Normal radial length on posteroanterior wrist radiography measures 10–13 mm, a key parameter for detecting distal radius fractures and malalignment.
Normal Radiocarpal Joint Space Size on Radiography
Normal radiocarpal joint space measures 2.0–2.5 mm on posteroanterior and lateral radiographs, with deviations indicating arthritis or ligamentous injury.