Accurate characterization of 99mTc-MDP uptake in extraosseous neoplasm mimicking bone metastasis on whole-body bone scan: contribution of SPECT/CT

Abstract

Background 99m Tc-labelled methylene diphosphonate ( 99m Tc-MDP) uptake can occasionally be identified in extraosseous neoplasms on whole-body scans (WBSs) and may be misinterpreted as bone metastasis. The purpose of our study was to investigate the frequency of 99m Tc-MDP uptake in extraosseous neoplasms and to assess the additional value of SPECT/CT for the localization and characterization of this unusual uptake. Methods Data from 7308 patients (SPECT/CT was performed in 2147 patients) with known cancer who underwent WBSs for metastatic work-up between May 2015 and July 2018 were retrospectively reviewed. The locations, numbers, and intensities of extraosseous 99m Tc-MDP uptake were evaluated by WBS, and the intratumoural calcification was evaluated by SPECT/CT. The diagnostic accuracy of SPECT/CT in locating 99m Tc-MDP uptake in extraosseous neoplasms was compared to that of WBS. Results A total of 41 patients showed 99m Tc-MDP uptake in extraosseous neoplasms. Of these patients, 23 patients had uncertain lesions by WBS, and further SPECT/CT was performed. The incidence of 99m Tc-MDP uptake in extraosseous neoplasms was observed to be 0.6% by WBS and 1.1% (by) SPECT/CT. During imaging analysis, WBS had an accuracy of only 35% (14/40), whereas SPECT/CT correctly located and diagnosed all 40 lesion sites in the 23 patients. Twenty-three lesion sites (57.5%, 23/40) showed moderate or high intensity of extraosseous 99m Tc-MDP uptake. Of the 23 patients, 17 patients (73.9%, 18/23) with 31 lesion sites (77.5%, 31/40) presented with intratumoural calcification. Conclusions 99m Tc-MDP uptake in extraosseous neoplasms can be observed as 0.6% on WBS and is usually localized to the breast, liver, and lung. Nuclear physicians should be familiar with such extraosseous uptake when interpreting WBSs. SPECT/CT offers better accuracy than WBS alone for locating the majority of lesions present with intratumoural calcification.

Quality Enhancement of Gamma Camera SPECT Images Via the Taguchi-Based Optimization of Their Minimum Detectable Difference And a V-Shaped Slit Gauge

“…The stdev values were assessed the ranked grade yi in each group, being further rearranged for each factor, together with the average and S/N values. Thus, the factor B (DTD) effect on the quality of gamma camera scan images at various levels (1, 2, or 3) was reflected by the average grades of groups (1, 2, 3, 10, 11, 12), (4, 5, 6, 13, 14, 15) or (7,8,9,16,17,18), as shown in Tables 1 and 2. The dependences linking average, stdev, and S/N values with each of six factors of the gamma camera scan protocol were visualized as fish-bone-plots in Figure 4.…”

“…It is a fast-screening tool for whole-body bone cancer metastasis [1,2] and is more efficient in tracking the preliminary syndrome from increased blood flow or osteogenetic activity enhancement than routine X-ray diagnosis because the latter requires the bone calcium changing by over ±35-50% for causing the apparent lesion [3,4]. Meanwhile, bones are one of the most common sites for metastases of all cancers, thus, an optimal preset of regular bone scan protocol can greatly help in examining the carcinoma in early stage from radiological viewpoint [5][6][7].…”

Focal Artefacts in Skeletal Scitigraphy

“…Так, по данным анализа 2147 остеосцинтиграмм, выполненных в режиме «все тело» и прицельной ОФЭКТ/КТ, внекостные «горячие» очаги констатированы у 1,1% пациентов. Наиболее часто они выявлялись в первичных и метастатических опухолях печени (30%), молочной железы (15%), легких (12,5%), существенно реже -яичников, матки и щитовидной железы [14]. Механизм данного феномена связывают с кальцификацией, в том числе микрокальцификацией, более выраженной при муцинозных опухолях и их метастазах [15].…”

Added Value of SPECT/CT in Characterization of Extra-Skeletal Uptake of Tc-99m MDP on Planar Bone Scintigraphy in Known Cancer Patients.

“…Extra-skeletal uptake in known cancer patients could be a problematic if it mimics metastatic osseous lesions. Extra-skeletal uptake on bone scintigraphy can occur due to different causes including traumatic, inflammatory, neoplastic, infarction, excretory, and iatrogenic (1)(2)(3)(4)(5) .…”