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Biomedical subjects

F S Chew

Publications and source records attributed to F S Chew.

134 records · Page 8Linked to original sources
PubMed1983

Scintigraphy of benign exostoses and exostotic chondrosarcomas.

Technetium-99m diphosphonate scintigraphy of 11 benign exostoses and nine exostotic chondrosarcomas was correlated with pathologic macrosections of the resected tumors. Increased uptake in benign exostoses occurred in areas of enchondral ossification, and uptake in chondrosarcomas occurred in areas where ossification, osteoblastic activity, and hyperemia were found. Uptake was not related to amorphous cartilage calcification. Radiopharmaceutical uptake, therefore, correlated with areas of ossification visible radiographically, and large masses of nonossifying cartilage were not detected. Radionuclide bone imaging did not contribute to the preoperative anatomic evaluation of these tumors, and it did not always distinguish benign from malignant lesions.

Adolescent↗
PubMed1982

Radionuclide bone scanning of osteosarcoma: falsely extended uptake patterns.

The pathologic specimens of 18 osteosarcomas of long bones were examined to correlate histologic abnormalities with abnormalities seen on preoperative 99mTc pyrophosphate or methylene diphosphonate bone scans. Seven scans accurately represented the extent of the tumor. Eleven scans disclosed increased activity extending beyond the radiographic abnormalities. In eight of these, there was no occult tumor extension and in the other three, the scan activity did not accurately portray the skip metastases that were present. Therefore, these 11 scans demonstrated the falsely extended pattern of uptake beyond the true limits of the tumors. Pathologic slides were available for 10 of the 11 areas of bone that exhibited extended uptake. In two instances, there was no pathologic abnormality. In the other eight cases we found marrow hyperemia, medullary reactive bone, or periosteal new bone. This is the first description of these histologic abnormalities of medullary bone in areas of extended uptake on radionuclide bone scans.

Adolescent↗
PubMed1982

Radionuclide bone scanning of medullary chondrosarcoma.

Technetium-99m methylene diphosphonate bone scans of 18 medullary chondrosarcomas of bone were correlated with pathologic macrosections of the resected tumors. There was increased scan uptake by all 18 tumors, and the uptake in 15 scans corresponded accurately to the anatomic extent of the tumors. Only three scans displayed increased uptake beyond the true tumor margins; thus, the "extended pattern of uptake" beyond the true tumor extent is much less common in medullary chondrosarcomas than in many other primary bone tumors. Therefore, increased uptake beyond the apparent radiographic margin of the tumor suggests possible occult tumor spread. Pathologically, there was intense reactive new bone formation and hyperemia around the periphery of all 18 tumors, and there were foci of enchondral ossification, hyperemia, or calcification within the tumor itself in nearly every tumor. Three scans displayed less uptake in the center of the tumors than around their peripheries. One of these tumors was necrotic in the center, but the other two were pathologically no different from tumors that displayed homogeneous uptake on the scan.

Bone Neoplasms↗
PubMed1981

Radionuclide imaging of soft tissue neoplasms.

Two classes of radiopharmaceuticals may be used for imaging tumors of the musculoskeletal system. The first is comprised of soft tissue or tumor specific agents such as gallium-67, bleomycin, and radionuclide-labeled antibodies, which may be useful for detecting and localizing these tumors. The other class of tracer is comprised of those with avidity for bone. The 99mTc-labeled-phosphate skeletal imaging compounds have been found to localize in a variety of soft tissue lesions, including benign and malignant tumors. In 1972, Enneking began to include bone scans in the preoperative evaluation of soft tissue masses. Later, he and his associates reported that these scans were useful in planning operative treatment of sarcomas by detecting involvement of bone by the tumors. Nearly all malignant soft tissue tumors take up bone-seeking radiopharmaceuticals, and bone involvement was indicated in two-thirds of the scans we reviewed. About half of benign soft tissue lesions had normal scans, but the other half showed uptake within the lesion and a few also showed bone involvement. Careful, thorough imaging technique is essential to proper evaluation. Multiple, high-resolution static gamma camera images in different projections are necessary to adequately demonstrate the presence or absence of soft tissue abnormality and to define the precise relationship of the tumor to the adjacent bone.

Bleomycin↗
PubMed1981

The role of radionuclide bone-scanning in determining the resectability of soft-tissue sarcomas.

In sixty patients with soft-tissue sarcoma, radionuclide bone scans were 92 per cent accurate in evaluating the presence or absence of involvement of contiguous bone by the tumor itself, by the tumor's reactive pseudocapsule, or by tissue contaminated during inadequate excision. The scans were most helpful when the relationship of the tumor to the bone was crucial in determining the resectability of the tumor. Meticulous imaging technique is essential to a complete and accurate radionuclide study. High-resolution, high-count gamma-camera scans in multiple projections are required for precise localization of tumor.

Biopsy↗
PubMed1980

Radionuclide imaging of lipoma and liposarcoma.

Radionuclide imaging with technetium-99m phosphate compounds was performed in 18 patients with deep-seated soft-tissue masses. The histologically established diagnosis was intra- or intermuscular lipoma in 13 patients and liposarcoma in five. Radionuclide scans demonstrated disparate scintigraphic characteristics in these two often clinically similar lesions. Soft-tissue radionuclide accumulation occurred in two lipomas and corresponded to radiographically evident calcification. All liposarcomas were uncalcified and demonstrated intense radionuclide activity. This activity may be related to the angiographic and histologic hypervascularity of liposarcomas, which is also demonstrable on computed tomography as contrast enhancement; hence, these modalities offer the same nonspecific diagnostic information. It is concluded, however, that plain radiography and radionuclide scaning should suffice to establish the diagnosis of lipoma.

Adult↗
PubMed1980

Radiology of infiltrating angiolipoma.

Infiltrating angiolipomas are rare benign soft-tissue neoplasms that are locally aggressive and require wide surgical excision. Of 10 patients studied, five showed serpiginous densities intermixed with fat on plain films. Six radionuclide bone scans showed uptake by the soft-tissue lesion. Eight angiograms demonstrated poorly marginated, very hypervascular lesions. Computed tomography (CT) in five patients yielded excellent visualization of predominantly low density lesions that invaded and replaced skeletal muscle. The combination of angiography and CT indicated the specific diagnosis and demonstrated the size, extent, and vascularity of the tumors.

Adult↗