Agreement of bone metastasis detection between bone scintigraphy and whole body-MRI in hepatocellular carcinoma
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Abstract
Background : Bone scintigraphy is generally accepted as the best imaging study for early detection of bone metastases. However, bone metastases from hepatocellular carcinoma (HCC), unlike other primary tumors, are largely osteolytic in nature and may be poorly visualized by bone scintigraphy (BS). Whole-body magnetic resonance imaging (MRI) has become feasible with recent developments, including fast image acquisition. So far, there has been no report of the performance of either imaging tool in the detection of bone metastasis from HCC.
Objective : To study the agreement of bone metastatic detection by bone scintigraphy and whole-body MRI in hepatocellular carcinoma patients.
Methods : A prospective study was carried out in 16 patients with HCC (mean age 54 years, range 41 - 70 years). All patients were assessed for bone metastasis with bone scintigraphy using Tc-99m methylene diphosphonate
(MDP) and whole-body MRI (coronal whole body and sagittal spine T1 weighted and short tau inversion recovery sequences). The bone lesions were assessed on each imaging investigation independently. Each patient was categorized into 1 of 4 categories, i.e. positive, probably positive, probably negative and negative. Extra-osseous metastases on MRI were also recorded.
Results : The study showed moderate agreement of bone metastasis detection between bone scintigraphy and whole body-MRI in patients with HCC (kappa = 0.5 with 95% Cl = 0.19 - 0.81). Eight of the 16 patients (50%)
were concordantly categorized. Whole body-MRI tended to identify more positive lesions in the spine, pelvis and appendicular skeleton, whereas bone scintigraphy tended to show more positive lesions in the ribs. Whole body-MRI identified extra-osseous metastases in 9 patients (56%), these included the lung, pelvic cavity and intramuscular of the thigh.
Conclusions : There is moderate agreement of bone metastasis detection between bone scintigraphy and whole body-MRI in patients with HCC. MRI tends to detect more lesions and is also useful for extra-osseous metastasis.