Imaging of metabolic bone disease and marrow disorders in children

Imaging of non-neuronopathic Gaucher disease: recent advances in quantitative imaging and comprehensive assessment of disease involvement

Gaucher disease is an inherited metabolic disorder resulting in deficiency of lysosomal enzyme β-glucocerebrosidase causing the accumulation of abnormal macrophages (“Gaucher cells”) within multiple organs, most conspicuously affecting the liver, spleen, and bone marrow. As the most common glycolipid metabolism disorder, it is important for radiologists encountering these patients to be familiar with advances in imaging of organ and bone marrow involvement and understand the role of imaging in clinical decision-making. The recent advent of commercially available, reliable, and reproducible quantitative MRI acquisitions to measure fat fractions prompts revisiting the role of quantitative assessment of bone marrow involvement. This manuscript reviews the diverse imaging manifestations of Gaucher disease and discusses more optimal quantitative approaches to ascertain solid organ and bone marrow involvement with an emphasis on future applications of other quantitative methods including elastography.

Calcium and Phosphorous in Pediatric Parenteral Nutrition

Calcium (Ca) and phosphorus (P) are essential for various systemic functions, including bone mineralization. Adequate provision of Ca and P in pediatric parenteral nutrition (PN) solutions is necessary for skeletal growth and for the prevention of metabolic bone disease. The provision of adequate doses of Ca and P in pediatric PN solutions is complicated by the increased needs in preterm and term infants, solubility limitations, and venous access. Clinicians should be aware of the evidence that supports the optimal use of Ca and P in pediatric PN solutions, including studies that have evaluated dosing and solubility. The aim of this article is to review relevant literature and practices for the use of these two minerals in pediatric PN solutions. The vitamin D endocrine system, a critical component for Ca homeostasis and bone mineralization, is discussed, as well as clinical manifestations of metabolic bone disease and methods for its prevention, assessment, and treatment in pediatric patients receiving PN.

Imaging of haemodialysis: renal and extrarenal findings

Electrolyte alterations and extra-renal disorders are quite frequent in patients undergoing haemodialysis or peritoneal dialysis. The native kidneys may be the site of important pathologies in patients undergoing dialysis, especially in the form of acquired renal cystic disease with frequent malignant transformation. Renal neoplasms represents an important complication of haemodialysis-associated acquired cystic kidney disease and imaging surveillance is suggested. Extra-renal complications include renal osteodistrophy, brown tumours, and thoracic and cardiovascular complications. Other important fields in which imaging techniques may provide important informations are arteriovenous fistula and graft complications.

Teaching points

• Renal neoplasms represent a dreaded complication of haemodialysis.

• In renal osteodystrophy bone resorption typically manifests along the middle phalanges.

• Brown tumours are well-defined lytic lesions radiographically, possibly causing bone expansion.

• Vascular calcifications are very common in patients undergoing haemodialysis.

• Principal complications of the AV fistula consist of thrombosis, aneurysms and pseudoaneurysms.

Tuberculous spondylodiscitis in a patient with a sickle-cell disease: CT findings

Background:

Although sickle-cell anemia (SCA) is common in black Americans, Sub-Saharan Africa and in the Mediterranean area, the disease is rare in the temperate climate zone. The manifestations of the disease are related mainly to the production of abnormal hemoglobin that leads to organ ischemia and increased susceptibility to infection caused by functional asplenia.

Case Report:

The authors present CT findings in a 39-year-old black woman diagnosed due to abdominal pain, lymphadenopathy and fever. CT of the thorax and abdomen demonstrated changes in the liver, spleen, and skeletal system suggestive of SCA complicated with spondylodiscitis in the thoracic spine.

Discussion:

Hepatomegaly and small calcified spleen are typical findings in older homozygotic patients with SCA. The lesions in the skeleton may be related either to intramedullary hematopoiesis or osteonecrosis and osteomyelitis. In the latter case, diffuse osteosclerosis and H-shaped vertebrae are most typical. Tuberculous spondylodiscitis is characterized by the location in the thoracic region, preferential involvement of anterior elements, relative sparing of intervertebral discs, and cold abscesses.

Bone Tumor Mimics: Avoiding Misdiagnosis

Whether discovered incidentally or as part of a focused diagnostic evaluation, the finding of a benign osseous lesion that has radiologic features resembling a bone tumor is not uncommon. Some of the more common benign and nonneoplastic entities that can sometimes be confused with tumors are the following: cortical desmoid, Brodie abscess, synovial herniation pit, pseudocyst, enostosis, intraosseous ganglion cyst, fibrous dysplasia, stress fracture, avulsion fracture (healing stage), bone infarct, myositis ossificans, brown tumor, and subchondral cyst. Accurate diagnosis and management of these lesions require a basic understanding of their epidemiology, clinical presentations, anatomic distributions, imaging features, differential considerations, and therapeutic options. This in-depth review of 13 potential bone tumor mimics will assist the radiologist in correctly identifying these benign lesions and in avoiding misdiagnosis and related morbidity. This review will also aid the radiologist in making appropriate recommendations to the referring physician for management or further imaging.

Bilateral transverse (Bowdler) fibular spurs with hypophosphatasia in an adolescent girl

Hypophosphatasia is a clinically heterogeneous inheritable disorder characterized by defective bone mineralization and the deficiency of serum and tissue liver/bone/kidney alkaline phosphatase activities. Due to the mineralization defect of the bones, various skeletal findings can be radiologically observed in hypophosphatasia. Bowing and Bowdler spurs of long bones are the characteristic findings. The Bowdler spurs reported on in the previous pertinent literature were observed in the perinatal aged patients and these lesions have rarely involved adolescents. We herein report on a 14-year-old girl with fibular Bowdler spurs.

Weismann-Netter-Stuhl syndrome in two siblings

Cases of Weismann-Netter-Stuhl syndrome involving the upper extremities and affecting siblings have rarely been reported. We present the radiological findings of Weismann-Netter-Stuhl syndrome in two siblings, with upper extremity involvement in one of them.

MRI of the marrow in the paediatric skeleton

Magnetic resonance imaging (MRI) has greatly advanced evaluation of marrow diseases of the paediatric skeleton. As with many other aspects of paediatric radiology it is important to recognize the normal variations in the appearance of the marrow that occur in the growing child. These normal variations need to be differentiated from diseases and conditions that affect the marrow. This review describes the normal changes that occur in children with age, and the appearances of the pathological changes seen in infection, infiltration, haematological disorders, transplantation and radiation therapy.

Whole-body magnetic resonance imaging: a useful additional sequence in paediatric imaging

BACKGROUND

Whole-body MR (WBMR) imaging allows the acquisition of images of the entire body in a matter of minutes. Its use has primarily been in the evaluation of possible metastases in the setting of a known primary tumour.

OBJECTIVE

To document the value of WBMR imaging in ten children in whom this was added as an additional sequence when the primary diagnosis had not yet been made.

MATERIALS AND METHODS

Ten children, age range 4 months-15 years (mean 7 years 4 months) had WBMR imaging after initial MR showed an abnormality that raised the possibility of systemic disease. Initial scanning was of the brain (n=1), spine (n=2), retroperitoneum (n=4), hips (n=1), femur (n=1) and wrist (n=1).

RESULTS

Abnormalities were detected in eight patients. Two patients had acute lymphoblastic leukaemia, and another had an anaplastic lymphoma, unsuspected prior to the WBMR. Two patients had a previously undiagnosed neuroblastoma with bone marrow metastases. Two patients had Langerhans' cell histiocytosis. Another had multiple bone lesions due to cystic angiomatosis.

CONCLUSIONS

WBMR imaging may be a useful additional sequence in children in whom a systemic and especially a bone marrow abnormality is suspected.

Variable presentations of rickets in children in the emergency department

Vitamin D-deficient rickets is uncommon but becoming more prevalent in the pediatric population likely related to increases in breast-feeding. It should be considered in many clinical situations. We present 3 cases of rickets presenting acutely to the emergency department. Their presentations included a fracture concerning for child abuse, tetany, and hypocalcemic seizures. In all cases, laboratory and radiographic evaluations were consistent with the diagnosis of nutritional rickets and their symptoms were related to rickets resolved with appropriate treatment. Although uncommon, vitamin D-deficient rickets should be considered in children with the above presentations.

Radiologic case study. Secondary hyperparathyroidism, osteomalacia with a pseudofracture, and amyloid deposition

The advancement of medical management of chronic renal failure has helped eliminate secondary hyperparathyroidism and osteomalacia. However, if a patient is recalcitrant, florid forms of both conditions can develop. Secondary amyloidosis is poorly understood but occurs in patients who are on long-term dialysis. As the survival rates for patients on long-term dialysis improve, it will be seen more frequently.

Imaging of renal osteodystrophy

Chronic renal insufficiency, hemodialysis, peritoneal dialysis, renal transplantation and administration of different medications provoke complex biochemical disturbances of the calcium-phosphate metabolism with wide spectrum of bone and soft tissue abnormalities termed renal osteodystrophy. Clinically most important manifestation of renal bone disease includes secondary hyperparathyroidism, osteomalacia/rickets, osteoporosis, adynamic bone disease and soft tissue calcification. As a complication of long-term hemodialysis and renal transplantation amyloid deposition, destructive spondyloarthropathy, osteonecrosis, and musculoskeletal infections may occur. Due to more sophisticated diagnostic methods and more efficient treatment classical radiographic features of secondary hyperparathyroidism and osteomalacia/rickets are now less frequently seen. Radiological investigations play an important role in early diagnosis and follow-up of the renal bone disease. Although numerous new imaging modalities have been introduced in clinical practice (scintigraphy, CT, MRI, quantitative imaging), plain film radiography, especially fine quality hand radiograph, still represents most widely used examination.