Presentation on theme: "How Common are Bone Islands on Abdominal and Pelvic CT?"— Presentation transcript:
1How Common are Bone Islands on Abdominal and Pelvic CT? Tamar Sella MDNurith Hiller MDAzraq Yusef MDEugene Libson MDJacob Sosna MDDept. of Radiology Hadassah Hebrew University Hospital, Jerusalem
2Bone Islands - Background focus of compact bone located in cancellous bonealso known as an enostosis, endosteoma, calcified medullary defecta benign entity that is usually found incidentally on imaging studiesbone islands may mimic a more agressive process, such as an osteoblastic metastasis
3Bone Islands - Pathophysiology exact etiology of bone islands is not clearMost likely developmental in nature: cortical bone that has failed to undergo medullary resorptionHistologically, bone islands are intramedullary foci of normal compact bone with haversian canals and "thorny" radiations that merge with the trabeculae of surrounding boneHamartoma?
4Bone Islands - Frequency The exact frequency is unknownPrevalence estimated as % based on plain radiographsMay be found in any osseous site; however, most commonly identified in the pelvis, long bones (most commonly proximal femur), also fairly common in ribs, and spine.
5Bone Islands – Plain films round or ovoid intramedullary sclerotic fociDo not extend beyond the cortexThe long axis typically parallels the long axis of the involved boneHomogeneously sclerotic with “thorny” radiating bone spicules that extend from the center of the lesion and blend with the trabeculae1 mm to 2 cm in diameter; size generally remains stable
6PurposeThe frequency of bone islands has been reported based on plain films onlyWhere digital workstations are used, bone windows are now routinely reviewed on every CT scanTo determine the frequency of small sclerotic lesions, most probably bone islands, on routine abdominal and pelvic CTs (AP CTs)
7Patients and MethodsWe prospectively examined AP CT scans of 263 consecutive patients referred over a 6 month periodPatients had no history of neoplastic disease or traumaFocal sclerotic round or oval lesions in the medulla of the bone were recorded.Data collected included size, location, and number of lesions per patient.
8Referral for CT Evaluate abdominal pain 137 Suspected renal colic 89 Other non-cancer related indication37Total263
9Patients and MethodsFor demographic purposes, patients were divided into three age groups:40 years or younger41-60 years61 years or aboveData was analyzed for the whole study population as well as for each age group
10Results 132 males (50%) 131 females (50%) BI found in 118 pts = 44.8% Age group# of patientsIncidence of BI≤ 4035 (29.6%)46%41-6041 (34.7%)44.5%≥ 6142 (35.5%)
11Results A Total of 161 BIs found in 118 pts single BI - 71% two BI - 21%three BI - 8%Size ranged from 1-13mm (mean 7mm, median 7mm).
12Results BI location: iliac bone 16.7% acetabulum 20.5% sacrum 16.7% femur %ischium %vertebrae 8%pubic bone 5%
13ConclusionBI are detected much more commonly on CT than previously reported on plain radiographs – 44.8%
14Work in progressOur study evaluated the incidence of BI in a general population (low risk).However, these lesions may cause confusion when incidentally found, mostly in oncology patients .Management guidelines need be established, taking in account their relatively high incidence.The incidence in an oncologic subset of patients is in evaluation.