Rickets- radiology

Dr jp,asst prof,ich,mch,kottayam

• The manifestations of rickets are most pronounced with rapid bone growth particularly the distal radius and ulna, distal femur, proximal tibia, proximal humerus, and anterior rib ends

• The initial radiographic finding in rickets is loss of mineralization of the zone of provisional calcification

• loss of definition of the Laval-Jeantet collar, a short cylindricalsegment of the metaphysis adjacent to the growth plate that is an indicator of the most recently formed bone in young infants

• Deficient chondrocyte terminal differentiation and apoptosis causes accumulation of disorganized cartilage in the metaphysis in addition to nonmineralized osteoid, leading towidening of the distance between the epiphysis and metaphysis,metaphyseal fraying, and metaphyseal concavity (cupping).

• Metaphyseal concavity varies by site, being most pronounced in the distal forearm bones

• Distal ulnar metaphyseal concavity with no other abnormality should be recognized as a normal finding.

• Metaphyseal findingsthat may be recognized on chest radiographs include involvement of the proximal humeral metaphyses and rib ends, producing the rachitic rosary

Vitamin D deficiency rickets. The initial image (left) shows loss of definition of the zones of provisional calcification for the distal radial and ulnar metaphyses along with metaphyseal fraying and concavity (“cupping”) and physeal widening with an increased distance between the epiphysis and visualized portion of the metaphysis.Periosteal new bone also is present that is seen best along the metacarpals but also is present along the distal radius.

With healing (right), the zone of provisional calcification is well mineralized and the other findings have resolved

Anteroposterior (A) and lateral (B) chest radiograph views in a 5-month-old child with rickets from biliary atresia. Note rickets in the proximal humeral metaphyses and anterior rib ends. The rib findings are best seen on the lateral view

less severe case of Vitamin D deficiency rickets. At 9½ years of age (top), distal femoral physealwidening and metaphyseal fraying is noted that resolved several monthslater after treatment (bottom).

Diaphyseal findings in a patient with severe vitamin D deficiency rickets. During the active phase (A), coarse demineralization and subperiosteal bone resorption are present, which are indicative of hyperparathyroidism as a result of rickets. Also note the severe rachitic findings in the metaphysis and poor mineralization of the distal radial epiphysis with loss of the zones of provisional calcification (arrow). With healing 3 months later (B), extensive periosteal new bone is seen (whitearrows) with calcification of previously nonmineralized osteoid (black arrows) produced by periosteal osteoblasts

Key points

• The initial radiographic finding in rickets is loss of mineralization of the zone of provisional calcification

• Isolated distal ulnar metaphyseal cupping is a normal variant in an infant and should not be confused with rickets

• Ref: caffeys pediatric diagnostic radiology 2013.