Correlation of 99mTc-sestamibi uptake with blood-pool and osseous phase 99mTc-MDP uptake in malignant bone and soft-tissue tumours

The complimentary role of Methoxy-Isobutyl-Isonitrile and hand-held gamma probe in adamantinoma

Adamantinoma is a rare locally aggressive osteolytic tumor that is found 90% of the time in the diaphysis of the tibia with the remaining lesions found in the fibula and long tubular bones. A case of adamantinoma of the tibia is presented. The added value of nuclear medicine investigations in the workup of this patient is described. A three-phase whole body ^99mTc-methylene diphosphonate bone and a whole body ^99mTc-methoxy-isobutyl-isonitrile scans were complimentary in the demarcation of viable bone tumor and the assessment of the remainder of the bone and soft tissue to exclude other sites. Intra-operative assistance with a hand-held gamma probe, guided the biopsy of the most metabolically active tumor tissue. Histology revealed a biphasic tumor composed of epithelial and fibrous components, in keeping with an adamantinoma.

Primary osteogenic sarcoma of breast detected on Tc-99m MIBI scintigraphy and Tc-99m MDP skeletal scintigraphy

A 64-year-old woman presented with a painless breast mass. Tc-99m methoxyisobutylisonitrile scintigraphy of both breasts showed a local area of abnormal uptake in the left breast in 5 min and 2 h. A skeletal scan showed very intense concentration of activity in the primary breast tumor in the left breast. A left mastectomy and an axillary dissection were performed. The predominant histologic type of the mass was an osteosarcoma, and the diagnosis of a primary osteogenic sarcoma of the breast was made. Primary osteogenic sarcoma of the breast is rare and represents less than 1% of all primary breast malignancies.

Evaluating benign and malignant musculoskeletal lesions with radionuclide angiography and SPECT using Tc-99m MIBI

PURPOSE

The purpose of this study was to evaluate the use of radionuclide angiography and single photon emission computed tomography (SPECT) using Tc-99m hexakis-2-methoxyisobutylisonitrile (Tc-99m MIBI) for analyzing musculoskeletal lesions.

MATERIALS AND METHODS

Radionuclide angiography and SPECT using Tc-99m MIBI were performed in 36 patients with various soft tissue and bone pathologies (18 benign and 18 malignant lesions). The ratio of the counts of the lesion to that of the contralateral normal area was calculated from the region of interest drawn on the MIBI scan. The MIBI-uptake ratio was calculated using SPECT and the MIBI-perfusion index was calculated using radionuclide angiography.

RESULTS

The MIBI-uptake ratio in malignant lesions (4.80 +/- 4.43) was significantly higher (P < 0.05) than that in benign lesions (1.83+/-2.48). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-uptake ratio for malignant lesions were 72%, 83%, 78%, 81%, and 75%, respectively. The MIBI-perfusion index in malignant lesions (17.68 +/- 21.19) was significantly higher (P < 0.05) than that in benign lesions (2.25 +/- 2.56). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the MIBI-perfusion index for malignant lesions were 87%, 75%, 81%, 77%, and 86%, respectively.

CONCLUSIONS

The MIBI-uptake ratio and MIBI-perfusion index using Tc-99m MIBI can yield important additional information with which to differentiate musculoskeletal lesions.

Usefulness of 201Tl and 99mTc MIBI scintigraphy in a case of oncogenic osteomalacia

A 45-year-old male was admitted with difficulty in walking due to leg pain. At the time of the first visit, a reduced serum phosphorus concentration and an increased serum alkaline phosphatase concentration of unknown etiology were observed. Either a whole body bone scintigraphy or CT of the neck, chest and abdominal region did not reveal any underlying disease. However both the whole body 201Tl scintigraphy and 99mTc MIBI SPECT showed accumulation in the right knee region, and a small tumor was detected by MRI examination. After a diagnosis of oncogenic osteomalacia due to this tumor was determined the tumor was surgically removed, and turned out to be a hemangiopericytoma. By removal of the tumor, either the symptoms or the laboratory data were improved significantly. In this case, both 201Tl scintigraphy and 99mTc scintigraphy MIBI were useful in identifying the location of the tumor which caused oncogenic osteomalacia.