Imaging Findings of Metabolic Bone Disease RadioGraphics preparacion para radiografia de columna lumbosacra

Metabolic bone disease encompasses a diverse group of diseases that diffusely affect the mass or structure of bones by an external process. These diseases have many causes, from genetic disorders, to nutritional deficiencies, to acquired conditions. The imaging manifestations are also varied, and the same disease process can have a wide range of skeletal findings ( 1). The purpose of this article is to review the radiographic findings of numerous metabolic bone diseases, including osteoporosis, rickets and osteomalacia, hypophosphatasia, hyperparathyroidism, renal osteodystrophy, hypoparathyroidism, hypothyroidism, hyperthyroidism, acromegaly, and scurvy.

Decreased bone mass is frequently observed in osteomalacia; however, it is not an essential feature in the diagnosis because an inability to mineralize newly synthesized osteoid does not imply that there is low bone mass of the skeleton.Preparacion para radiografia de columna lumbosacra


the presence of large quantities of unmineralized osteoid can sometimes be observed as indistinct ill-defined trabecular bone, because osteoid on the surface of the trabeculae is intermediate in density between that of bone and that of marrow, sometimes giving the impression of a “poor-quality” radiograph.

Looser zones are another distinctive feature of osteomalacia. They occur late in the overall course of the disease ( fig 5 ). Looser zones are the result of deposition of unmineralized osteoid at sites of stress or along nutrient vessels. These zones can occur with no or minimal trauma, are often bilateral and symmetric, and appear as transverse lucent bands oriented at right angles to the cortex that only span a portion of the bone diameter. Although known as pseudofractures, looser zones are a type of insufficiency fracture, with locations and appearances modified by abnormal repair mechanisms, and looser zones are typically painful.Preparacion para radiografia de columna lumbosacra some of the common locations of looser zones are similar to those of stress fractures, such as the inner margin of the femoral neck or the pubic rami. However, looser zones also occur in non–weight-bearing bones, which are atypical locations for stress fractures, such as the lateral aspect of the femoral shaft at the level of the lesser trochanter, the ischium, the iliac wing, and the lateral scapula ( 23, 24).

Figure 8a. Hypophosphatasia in a neonate with a low serum alkaline phosphatase level (5 IU/L) who had short femoral length at prenatal US (images not shown). (a) anteroposterior radiograph shows abnormal ossification in the axial and appendicular skeleton, with a thin calvaria, thin clavicles and ribs, small vertebral bodies, small scapulae and ilia, stunted ends of the long bones, and poor ossification of the short tubular bones in the hands. (b) posteroanterior chest radiograph obtained at the age of 6 months, after administration of recombinant enzyme replacement therapy, shows a remarkable increase in the ossification of the ribs, clavicles, scapulae, vertebrae, and long bones.Preparacion para radiografia de columna lumbosacra the ends of the ribs and long bones are broader than normal because of the accumulation of osteoid in patients with hypophosphatasia. (images courtesy of gen nishimura, MD, st. Luke’s international hospital, tokyo, japan.)

Figure 8b. Hypophosphatasia in a neonate with a low serum alkaline phosphatase level (5 IU/L) who had short femoral length at prenatal US (images not shown). (a) anteroposterior radiograph shows abnormal ossification in the axial and appendicular skeleton, with a thin calvaria, thin clavicles and ribs, small vertebral bodies, small scapulae and ilia, stunted ends of the long bones, and poor ossification of the short tubular bones in the hands. (b) posteroanterior chest radiograph obtained at the age of 6 months, after administration of recombinant enzyme replacement therapy, shows a remarkable increase in the ossification of the ribs, clavicles, scapulae, vertebrae, and long bones.Preparacion para radiografia de columna lumbosacra the ends of the ribs and long bones are broader than normal because of the accumulation of osteoid in patients with hypophosphatasia. (images courtesy of gen nishimura, MD, st. Luke’s international hospital, tokyo, japan.)

Hyperparathyroidism is a pathologic state of elevated parathyroid hormone concentrations, which causes increased bone resorption. Primary hyperparathyroidism is a state of autonomous parathyroid hormone secretion by the parathyroid glands and lack of feedback inhibition by serum calcium. Primary hyperparathyroidism is usually caused by a parathyroid adenoma, but in approximately 10% of cases, it is a result of four-gland hyperplasia, and in extremely rare cases, primary hyperparathyroidism is due to parathyroid carcinoma ( 29).Preparacion para radiografia de columna lumbosacra secondary hyperparathyroidism is more common than primary hyperparathyroidism and is a response to low serum calcium levels. The most common cause is chronic renal failure, in which chronically elevated serum phosphate levels depress the serum calcium level, which leads to compensatory hyperplasia of the chief cells of the parathyroid gland. Renal insufficiency also affects parathyroid hormone metabolism, further increasing the serum parathyroid hormone levels. Secondary hyperparathyroidism can also be observed in vitamin D deficiency and dietary calcium deficiency ( 30).

Hypoparathyroidism is most commonly an acquired disorder caused by iatrogenic injury to the parathyroid glands during thyroid surgery or excision of the parathyroid glands or, more rarely, during wide excision of a head and neck cancer.Preparacion para radiografia de columna lumbosacra hypoparathyroidism may also result from autoimmune disease or genetic causes (eg, digeorge syndrome) ( 44, 45). End-organ insensitivity to parathyroid hormone is called pseudohypoparathyroidism and has different radiographic findings. Hypoparathyroidism that is due to genetic causes usually manifests in childhood, but the clinical spectrum varies widely, and in some cases, hypoparathyroidism may not be detected until adulthood ( 46, 47).

Radiographic findings of hypoparathyroidism reflect an overall increase in bone mass, including generalized or localized osteosclerosis and thickening of the calvaria, with a narrowed diploic space. In rare cases, spinal ossification similar in appearance to the enthesitis observed in psoriatic arthritis can occur ( 47– 51).Preparacion para radiografia de columna lumbosacra

Figure 21a. Scurvy in a 4-year-old boy with speech delay, a history of difficulty walking for 1 month, and a serum vitamin C level of 0.08 mg/dl (normal range, 0.2–2.0 mg/dl). (a) anteroposterior radiograph of both knees shows diffuse osteopenia, frankel lines (arrowheads), trummerfeld zones or scurvy lines (dashed arrows), widening of the growth plate (solid arrows), and subepiphyseal corner fracture (circle). Because of the metaphyseal lucent bands, the patient was initially thought to have leukemia or metastases, but the findings from histopathologic examination of the specimen from bone marrow biopsy were normal. (b) coronal T2-weighted fat-suppressed MR image of both distal femoral metadiaphyses shows heterogeneously increased T2 signal intensity in the marrow (*) and around the bone (arrows). (images courtesy of gen nishimura, MD, st.Preparacion para radiografia de columna lumbosacra luke’s international hospital, tokyo, japan.)

Figure 21b. Scurvy in a 4-year-old boy with speech delay, a history of difficulty walking for 1 month, and a serum vitamin C level of 0.08 mg/dl (normal range, 0.2–2.0 mg/dl). (a) anteroposterior radiograph of both knees shows diffuse osteopenia, frankel lines (arrowheads), trummerfeld zones or scurvy lines (dashed arrows), widening of the growth plate (solid arrows), and subepiphyseal corner fracture (circle). Because of the metaphyseal lucent bands, the patient was initially thought to have leukemia or metastases, but the findings from histopathologic examination of the specimen from bone marrow biopsy were normal. (b) coronal T2-weighted fat-suppressed MR image of both distal femoral metadiaphyses shows heterogeneously increased T2 signal intensity in the marrow (*) and around the bone (arrows). (images courtesy of gen nishimura, MD, st.Preparacion para radiografia de columna lumbosacra luke’s international hospital, tokyo, japan.)