Table 1.

The Expert Panel's Recommendations for Monitoring Bone Involvement in Gaucher Patients

Area to assess	Technique	Parameter to measure or scoring system	Comments
BMD (osteopenia, osteoporosis)
Adults: LS and left and right hips In clinical practice, usually only one hip is scanned, but a dual hip scan is recommended to provide a comparison In patients with LS collapse or hip osteonecrosis, use a less‐affected site for measurement (e.g. distal third of the radius and/or calcaneus of the non‐dominant leg)	DXA Serial DXA scans should be performed using the same device When assessing therapeutic effects or serial evaluations, changes need to be related to the smallest significant changes detectable by the centre and machine used Patients aged <50 years (including premenopausal women): evaluate Z‐score Check once every 2–4 years Patients aged >50 years, postmenopausal women (evaluate T‐score), and glucocorticoid‐treated patients Check every 1–2 years Assess every 24–36 months (untreated patients) or every 36 months (patients whose goals for skeletal involvement have been achieved on ERTa) Repeat at shorter intervals (e.g. 12–24 months) if rapid loss of bone mass is likely (e.g. patients on corticosteroid therapy) During treatment, allow at least 12 months between BMD evaluations	Essential parameters to measure: Bone mineral content (g) Bone area (cm2) BMD (g/cm2) Calculated Z‐score Z‐score <‐2.0 indicates reduced BMD An increase in BMD Z‐score with treatment is usually accompanied by improvement in bone pain and bone crises Postmenopausal women and men older than 50 years Use the T‐score Interpret using the WHO classification of osteopenia and osteoporosis	Relatively inexpensive, widely available, and associated with low radiation exposure, but It may give erroneous results in areas of damaged bone – may result in false high or false low BMD depending whether lytic or infarction lesions are present – may result in false high BMD if compression fractures have occurred A DXA‐based BMD does not correlate with the risk of fracture in all patients (e.g. premenopausal women) Reimbursement differs by location – e.g. in the USA, most insurance plans and Medicare will pay for DXA only biannually unless a clear medical need can be demonstrated Interpretation of scans can be aided by plain radiography Consider radiation exposure
Children: total body less head	DXA in children older than 5 years	Z‐score, age‐adjusted BMD	Particularly consider radiation exposure
Active bone disease
Pelvis, vertebrae, and limbs	MRI	BM oedema Bone infarcts Periosteal bleeding	Active bone disease is indicated by a high signal on STIR sequences
	T1, STIR, orientation depending on the anatomical site
Whole body	MRI	DGS, BMD, VDR	Significant limitations make these options impractical for widespread use Expense, complexity, low availability
	Whole body: coronal T1, STIR
	Axial skeleton: sagittal T1, T2, STIR, composed of cervical, thoracic, and LS
	Abdomen and pelvis: axial T2, T2‐fat‐sat
BM fat fraction	QCSI, STIR‐weighted sequences	Fat fraction in LS	Correlates with fracture risk Limited availability
Marrow infiltration and bone involvement (pathological fractures, osteonecrosis, lytic lesions, Erlenmeyer flask deformity)
BM cavity	MRI	Semi‐quantitative scoring Dusseldorf‐Gaucher Score (DGS) Bone‐marrow Burden (BMB) score	Gold standard for assessment of bone involvement in Gaucher patients
Axial skeleton (BM fraction) and lower extremities	Spin‐echo technique, T1, T2, STIR,
	LS: sagittal, T1, T2, STIR,
			More accurate than plain radiography for detecting early skeletal involvement
	lower extremities: coronal, T1, T2, STIR
			Can provide undistorted images of marrow cavity
Axial and appendicular skeleton e.g. fractures, osteoarthrosis, osteosyntheses	Plain radiography (depending of the anatomical site, e.g. hips, knee, LS, etc.)	Radiomorphological imaging	Can be used for diagnosis and for specific lesions Widely available Provides important baseline information on skeletal status
			Not suitable for monitoring acute bone crises
			Consider radiation exposure, especially in children
	Aspiration biopsy should not be used for diagnosis of GD		Biopsy should be performed only when malignancy or other haematological disease is suspected
Malignancy
BM	Biopsy may be indicated	Karyotype to detect chromosomal abnormalities consistent with multiple myeloma Mutation analysis may also be sometimes indicated to detect multiple clones	Treatment should follow guidelines appropriate for the tumour type Take care to minimize myelotoxic effects of chemotherapy
Blood	Serum protein electrophoresis and immunofixation test at baseline and follow‐up Every 2 years (patients aged 40–50 years) Annually (patients aged >50 years) MGUS screening is not necessary in children or young adults	Identify abnormal Ig profile (including free light chains in serum and urine)	Multiple myeloma does not preclude use of ERT a Aggressive myeloma may not allow sufficient time for ERT a to take effect

^aERT is used in this article as an umbrella term and includes various molecules used in ERT and SRT. Relevant differences may exist and review of the local label of a particular treatment is recommended when considering potential benefits in bone biology and clinical efficacy.