Pediatric musculoskeletal ultrasound: a pictorial essay

Abstract

Ultrasound (US) is the main imaging modality for the evaluation of pediatric patients with musculoskeletal diseases; particularly, it is an appropriate and reliable tool for diagnosis, follow-up and treatment of several musculoskeletal pathologies affecting the pediatric age. High-frequency (10-15 MHz) and high-resolution probes provide very lofty quality images, allowing a detailed study of the pediatric musculoskeletal system. Among the well-known advantages of this technique-such as the absence of ionizing radiations, its low cost and wide availability-US can as well rely on some intrinsic characteristics of the pediatric musculoskeletal system that can improve its diagnostic capability. The unossified portions of the pediatric skeleton and the absence of a thickened adipose tissue allow US to be highly effective and reliable in the study of muscles, tendons and cartilage. Lower-frequency sectoral transducers can be required in the study of some joints such as the shoulder or the hip, as well as in the examination of deep soft-tissue lesions. Furthermore, both color and spectral Doppler play an important role in the examination of soft-tissue lesions and synovial phlogosis. In this pictorial essay the main pathological conditions of pediatric musculoskeletal system will be examined, such as painful hip, evolutionary hip dysplasia, osteochondrosis, trauma-related pathologies and juvenile idiopathic arthritis.

Keywords: High-resolution probes; Musculoskeletal system; Pediatric age; Ultrasound examination.

Fig. 1

Anisotropic artifact: normal hyperechoic tendon (a), and ipoechoich appearance of the same tendon due to anisotropy artifact (b)

Fig. 2

2-Year-old child: the femoral diaphysis appears on the ultrasound examination as a hyperechoic line with a rear shadow cone; the epiphyses and the apophyses are partially or totally cartilaginous, and appear on the ultrasound examination as hypo-anechogenic structures due to the high water content of the cartilage

Fig. 3

Few examples of muscular (a), tendon (b), ligament (c), and nerve scans (d)

Fig. 4

Six-year-old boy with fever, limping on the left side. Joint effusion in the anterior recess of the joint capsule in patient with transient synovitis of the hip

Fig. 5

Five-year-old boy presenting with persistent fever and atraumatic right hip pain. Slightly corpusculated and inhomogeneous anterior joint recess effusion in septic arthritis of the pediatric hip

Fig. 6

Irregular and fragmented aspect of the femoral head, and hypotrophy of the quadriceps of the affected side (a) compared to the healthy control (b) in a 5-year-old girl with persistent atraumatic left hip pain

Fig. 7

Correct ultrasound scan for the study of hip dysplasia showing: labrum (green arrow), acetabular cartilage (blue arrow), bony rim of acetabulum (red arrow), and lower limb of the iliac bone (light blue arrow)

Fig. 8

Hip type Ia (a) and type Ib (b) according to Graaf classification

Fig. 9

Hip type IIa+ (a) and type IIb (b) according to Graaf classification

Fig. 10

Hip type IIc (a) and type III (b) according to Graaf classification

Fig. 11

Ten-year-old boy with Osgood Schlatter disease presenting with pain in the front lower part of the left knee. US examination shows: effusion of the infrapatellar bursa (a); cartilage tumefaction, accretion nucleus fragmentation, and thickening of the tendon (b)

Fig. 12

Sinding–Larsen–Johansson disease in a 11-year-old girl with anterior, spontaneous knee pain and swelling at the inferior pole of the patella. US examination demonstrates fragmentation of the lower pole of the patella and the signs of tendinopathy at insertion of the patella tendon

Fig. 13

Longitudinal scan images of detachment of the SIAI (antero-inferior iliac spine) with (a) and without (b) color Doppler in a patient with history of recent trauma, unilateral hip pain, absence of joint effusion with lameness, pain and suspected coxite

Fig. 14

US findings in an 8-year-old boy with Juvenile idiopathic arthritis of the left knee presenting with functional limitation, pain and low grade fever: synovial effusion and thickening (a), synovial flogosis (b) and cartilage and marginal bones erosion (c)