Tc-99m MDP Uptake Research Articles

Incidental Ovarian Uptake in Bone Scintigraphy.

A 47-year-old woman, recently diagnosed with breast cancer, underwent staging. A whole-body bone scan revealed an unexpected focal 99mTc-MDP uptake in her right ovary. Extensive literature review suggested various malignant pathologies for this incidental ovarian uptake. Despite inconclusive results from other imaging modalities, the multidisciplinary tumor board recommended right ovarian resection due to a history of abnormal uterine bleeding. The final pathology confirmed an adult-type granulosa cell tumor. Interestingly, subsequent surgery performed for staging purposes found no additional tumor sources. This case highlights the enhanced diagnostic value of hybrid imaging in bone scintigraphy.

Unusual finding on bone scintigraphy: Cerebral 99m-tc mdp involvement

99mTc-MDP (99mTc-methylene diphosphonate) uptake in the brain parenchyma was observed in the scintigraphic imaging of a 56 years old male patient with renal cell carcinoma (RCC), who was referred to our clinic for metastasis screening due to widespread bone pain. Uptake of 99mTc-MDP in the brain parenchyma in bone scintigraphy is a rare finding. This case is presented to reveal the causes of cerebral 99mTc-MDP involvement.

KÜÇÜK HÜCRELİ DIŞI AKCİĞER TÜMÖRLERİNİN DEĞERLENDİRİLMESİNDE Tc-99m MIBI SPECT’İN YERİ

Objective: In this study, it was aimed to investigate the role of Tc-99m MIBI scintigraphy in the diagnosis and evaluation of non-small cell lung cancers and also to evaluate the use of MIBI scintigraphy and MDP bone scintigraphy together in the detection of metastases. Methods: For this purpose, 30 patients with non-small cell lung cancer and 15 patients with benign lesions other than lung cancer (as a control group) were included in the study. By applying Tc-99m MIBI and Tc99m MDP scintigraphy to whole patients with benign and malign lung lesions, anterior-posterior planar and SPECT MIBI images were obtained. Bone scintigraphy was performed as whole-body images. Scintigraphic findings were compared with the histopathological diagnosis of patients. Data were analyzed statistically. Results: According to the result of the findings, the sensitivity, specificity, positive, predictive value, negative predictive value, and accuracy rate of Tc-99m MIBI scintigraphy in the detection of non-small cell lung tumors were determined as 87%, 93.5%, 96%, 77.7%, and 88.8%, respectively. Scintigraphic findings were evaluated quantitatively and visually. While there was no statistically significant difference between the early uptake rates of non-small cell lung tumors and benign lesions in the quantitative evaluation using planar MIBI images, late Tc-99m MIBI uptake rates were significantly higher in lesions with non-small cell lung tumors than that of benign lesions. However, it was detected that both the early and late uptake ratios were significantly higher in malign lesions than in benign lesions in the quantitative evaluation of SPECT images. It was observed that MIBI washout in benign lesions was higher than in malignant lesions in visual washout analysis. Additionally, multiple bone metastases were observed in 14 patients on the visual evaluation of bone scan of the patients with non-small cell lung cancer. Tc-99m MDP uptake was not observed in the malignant lung lesion region or in the soft tissue except the lesion. Conclusion: In light of the findings, it was concluded that Tc-99m MIBI scintigraphy is a noninvasive method with high sensitivity and specificity that can be used to differentiate non-small cell lung tumors from benign lesions.

A case report of early detection of rare femoral shaft bone metastasis in a penis cancer patient

Background. Bone metastasis is very common in the advanced stage of numerous carcinomas. In penile carcinoma, lymph nodes metastasis is somehow common but it is very rare reported to be secondary from penile cancer. till the date, there are only few cases of penis carcinoma reported bone metastasis in literature worldwide.Case Presentation. Herein, We presented a 51-year-old Nepalese male with squamous cell carcinoma of penis. computed tomography (ct) scan of the patient revealed that there was carcinoma involving glans penis and precure with bilateral external & internal inguinal lymphadenopathies. After then, the patient was under gone for partial penectomy and bilateral inguinal lymphadenectomy and complete 6-cycle chemotherapy. After one year of treatment, patient developed thigh pain and headache and he advised to have magnetic Resonance imaging (mRi) of brain, 99mTc-MDP whole body bone scan and ct scan of pelvis and thigh. The examination report reveals that there was a sclerotic change in vertex of skull bone and moderate 99mTc-MDP uptake in right proximal shaft of femur just below the neck d/d metastasis. The histopathological examination of the true cut biopsy taken from the lesion of the femur showed metastatic keratinizing squamous cell carcinoma which is rare case of femoral shaft bone metastasis secondary from penile carcinoma. Then patient was sent for surgical reconstruction of femur. Based on the case studies review femur shaft bone metastasis from penile cancer is extremely rare.Conclusion. The best of our knowledge; this is the first early detected bone metastases to shaft of the femur in a patient with penile cancer. early diagnosis helps to radical treatment as well as palliative treatment. surgery is the preferred option of the treatments, especially for metastatic foci in the long bones.

Extraosseous Uptake and Multiple Metastases of Splenic Composite Hemangioendothelioma on 99mTc-MDP Scintigraphy.

Composite hemangioendothelioma is a rare disease that exhibits biological potency ranging from benign to low-grade malignancy, and hepatic and bone metastases are even rarer. Here, we present the imaging findings of a 65-year-old man with splenic composite hemangioendothelioma and multiple metastases. A bone scan revealed abnormal uptake of 99mTc-MDP in multiple bones and spleen, whereas enhanced CT demonstrated splenic lesions with low density and mild enhancement. Based on pathological examination, the patient was diagnosed with splenic composite hemangioendothelioma with bone metastasis.

The clinical effectiveness of fused image of single-photon emission CT and facial CT for the evaluation of degenerative change of mandibular condylar head

BackgroundThe primary objective of this study was to assess the clinical effectiveness of fused images obtained from single-photon emission computed tomography (SPECT) and facial computed tomography (CT) for evaluating degenerative changes in the mandibular condylar head. This assessment was accomplished by comparing the Technetium-99 m methylene diphosphonate (99mTc-MDP) uptake ratio with the results of clinical and radiographic findings.MethodsThe study included 17 patients (3 males and 14 females) with suspected osteoarthritis of the mandibular condyle, totaling 34 temporomandibular joints (TMJs). Based on clinical and radiographic examinations, the TMJs were categorized into four groups: normal (group N), internal derangement (group ID), osteoarthritis (group OA), and osteoarthritis sequelae (group OAseq). For each patient, bone SPECT and facial CT scans were registered and reconstructed to create fused SPECT/CT images. The 99mTc-MDP uptake levels in the TMJs were statistically compared among the four groups.ResultsThe 99mTc-MDP uptake ratio showed a gradual increase in the order of the following: group N, group OAseq, group ID, and group OA. There was a significant difference observed among groups (p = 0.003), mainly driven by the disparity between group OA and both group N (p < 0.001) and group OAseq (p = 0.048).ConclusionFused SPECT/CT image can be an effective tool for evaluating degenerative changes in the mandibular condylar head. The technique demonstrated the ability to differentiate between normal TMJs and those with internal derangement, osteoarthritis, or osteoarthritis sequelae. This approach holds promise as a valuable method in clinical assessments of TMJ degeneration.

Intense Splenic 99m Tc-MDP Uptake in Patient with Langerhans Cell Histiocytosis

Intense Splenic 99m Tc-MDP Uptake in Patient with Langerhans Cell Histiocytosis

Role of MDP SPECT/CT Bone Scintigraphy in Evaluation of Patients with Malignant Otitis Externa Compared to HRCT: A prospective Study.

Background: Malignant otitis externa (MOE) is a potentially fatal disease; accurate assessment of the extent of this disease is warranted to plan the course of treatment and to predict the prognosis. The aim of the study was to compare the efficiency of high resolution computed tomography (HRCT) with that of 99mTechnetium methylene diphosphonate (99mTc-MDP) single photon emission computed tomography/computed tomography (SPECT/CT) in precise evaluation of the disease extent and to evaluate the prognostic value of SPECT/CT staging in terms of therapeutic response and survival in patients with MOE. Patients and Methods: This prospective study included twenty-five patients (17 males and 8 females) with clinically diagnosed MOE, all of themunderwent both HRCT and 99mTc-MDP SPECT/CT imaging of the skull. Based on 99mTc-MDP uptake in SPECT/CT scan, the findings were staged accordingly and compared with the findings of HRCT in all patients. In addition, clinical outcome and disease-free survival (DFS) were analyzed according to the SPECT/CT staging.Results: Out of 25 patients included in our study, HRCT showed osseous changes in only 4/25 (16%) patients, 99mTc-MDP SPECT/CT demonstrated more osseous involvement in 21/25 (84%) patients. No patients in stage I in this work, 8 patients had disease confined to the mastoid/temporal bone, not reaching midline (stage II), 6 of them were surviving with recovery and clinical improvement, and 2 patients died. Three patients had petrous involvement reaching midline (stage III), 2 of them were surviving with clinical improvement, and the 3rd patient died. Fourteen patients had sphenoid involvement/disease extended to the contralateral temporal bone (stage IV), 5 of them were surviving with recovery and clinical improvement, 5 were surviving, yet had disease progression, and 4 patients died within less than one year of diagnosis. At the end of follow up period; in total; 7 patients had died,of whom 3 in stage IV died due to MOE, while the remaining 4 cases (2 in stage II, 1 in stage III, and 1 in stage IV) died due to unrelated causes. Both of disease duration and SPECT/CT staging were statistically significant predictor factors for DFS (P=0.05 and 0.047 respectively).Conclusion: SPECT/CT has a higher sensitivity than HRCT in determining the exact extent of MOE and was much better correlated with disease prognosis.

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

Introduction: Extra-skeletal Tc-99m MDP uptake is not uncommon. It could be a problematic when it mimics a metastatic osseous lesion. Due to lack of proper anatomical localization, Planar bone scintigraphy (PBS) alone can't resolve this problem. Adding single photon emission tomography / computed tomography (SPECT/CT) images increases the diagnostic accuracy of planar bone scintigraphy. SPECT/CT has great impact on patients' management by preventing misinterpretation through precise localization and proper characterization of these uncertain lesions. In this study, we compared the diagnostic accuracy of SPECT/CT versus PBS in characterization of extra-skeletal lesions detected on conventional PBS in known cancer patients. Materials and Methods: This is a retrospective study including 50patients with known cancer referred for conventional (PBS) for metastatic work up. PBS was acquired followed by SPECT/CT images for the concerned area. Diagnostic performance indices from both modalities (PBS& SPECT/CT) were compared against the reference standard (clinical/imaging follow-up). Results: A total of 50 known cancer patients were included in this study (37 females, 13 males) with median age 64 years (range: 15-79). The sensitivity, specificity, and accuracy for SPECT/CT in identification of extra-osseous lesions all were 100% compared to 28%, 72% and 44% respectively for PBS. Uncertain lesions decreased from 38% to 0% by adding SPECT/CT.Only 10% of lesions showed calcium deposition, while the rest had other causes for extra-skeletal uptake. Conclusion: SPECT/CT enhances the diagnostic accuracy of planar bone scan for characterizations of extra-skeletal lesions that mimic osseous metastasis thus significantly impact patient’s management.

Added diagnostic value of SPECT to evaluate bone metastases inbreast cancer patients with normal whole body bone scan.

Background:In this research, we aimed to survey the added value of single photon emission computed tomography (SPECT) in comparison with planar whole body bone scan to visualize bone metastatic lesions in patients with breast cancer.Methods:A total of 80 patients with breast cancer (invasive ductal carcinoma) were examined with planar whole body bone scan and SPECT imaging using 99mTc-labelled methylene diphosphonate (99mTc-MDP). The patients with abnormal uptakes in SPECT imaging were also investigated with magnetic resonance imaging (MRI).Results:Among these 80 patients with normal whole body bone SPECT scan, 19 (23.25%) of them revealed abnormal 99mTc-MDP uptake in skeleton. Furthermore, these 19 patients were subjected to MRI and 3 (3.75%) of them were confirmed with metastatic bone lesion.Conclusion:The obtained data suggest that SPECT possess the added diagnostic over planar whole body bone scan.

Rhabdomyolysis following coronary angiography: an unexpected detection on 99mTc-methyl diphosphonate bone scintigraphy

BackgroundBone scintigraphy is an appropriate tool in the management of cancers for the detection of bone metastasis. Technetium 99 m-methylene diphosphonate (99mTc-MDP) is commonly used as a bone-seeking agent. The bones take up 99mTc-MDP through a process called chemisorption, which is more evident in areas of increased osteoblastic activities. Nevertheless, extra-osseous 99mTc-MDP uptake is an infrequent occurrence, which warrants a thorough clinical assessment to evaluate such findings. An example of extraosseous uptake discovery is rhabdomyolysis, which requires prompt recognition and immediate management. Rhabdomyolysis secondary to an adverse reaction towards iodinated contrast material is a rare condition that warrants a high index of clinical suspicion.Case presentationWe present a case of a 75-year-old gentleman with underlying benign prostatic hypertrophy, and chronic kidney disease who had undergone a coronary angiography examination and intervention for ischemic heart disease. Pre-scheduled bone scintigraphy with 99mTc-MDP for the work-up of raised serum prostate-specific antigen (PSA) was performed 2 weeks post coronary angiography examination. Whole-body bone scan with single-photon emission computed tomography/computed tomography (SPECT/CT) images showed an unexpected finding of extensive extra-osseous uptake in the muscles and soft tissues. Additional investigations confirmed the diagnosis of rhabdomyolysis. Nevertheless, despite the prompt recognition, administration of treatment and supportive care, the patient succumbed to life-threatening complications.ConclusionThis case highlights the importance of recognising and identifying the pattern of extra-osseous uptake on bone scintigraphy imaging to ensure early intervention of severe and life-threatening conditions such as rhabdomyolysis.

Dosimetric considerations of 99mTc-MDP uptake within the epiphyseal plates of the long bones of pediatric patients

Skeletal scintigraphy is most performed in pediatric patients using the radiopharmaceutical 99mTc labelled methylene diphosphonate (99mTc-MDP). Reference biokinetic models for 99mTc-MDP indicate 50% of the administered activity is uniformly localized to the interior bone surfaces (trabecular and cortical regions), yet imaging data clearly show some preferential uptake to the epiphyseal growth plates of the long bones. To explore the dosimetric consequences of these regional activity concentrations, we have modified mesh-type computational phantoms of the International Commission on Radiological Protection (ICRP) reference pediatric series to explicitly include geometric models of the epiphyseal growth plates (2 mm in thickness) within the left/right, distal/proximal ends of the humeri, radii, ulnae, femora, tibia, and fibulae. Bone mineral activity from the ICRP Publication 128 biokinetic model for 99mTc-MDP (ICRP ) was then partitioned to the growth plates at values of 0.5%, 4.4%, 8.3%, 12.2%, 16.1%, and 20%. Radiation transport simulations were performed to compute 99mTc S-values and organ dose coefficients to the soft tissues and to bone site-specific regions of spongiosa. As the percentage of bone activity assigned to the growth plates was increased (from 0.5% to 20%), absorbed doses to the soft tissue organs, active bone marrow, bone endosteum (BE), as well as the detriment-weighted dose, were shown to decrease from their nominal values (no substantial growth plate activity), while epiphyseal plate self-doses increased. In the 15 year old male phantom, moving from 0.5% to 20% relative bone activity within the epiphyseal plates resulted in a 15% reduction in active marrow (AM) and BE dose, a 10% reduction in mean soft tissue and detriment-weighted dose, and a 6.3-fold increase in epiphyseal plate self-dose. In the newborn female phantom, we observed a 18% decrease in AM and BE dose, a 10% decrease in mean soft tissue dose, a 15% decrease in detriment-weighted dose, and 12.8-fold increase in epiphyseal plate self-dose. Increases (to 3 mm) and decreases (to 1 mm) in the assumed growth plate thickness of our models were shown to impact only the growth plate self-dose. Future work in differential quantification of 99mTc-MDP activity—growth plates versus other bone surfaces—is required to provide clinically realistic data on activity partitioning as a function of patient age, and perhaps skeletal site. The phantom series presented here may be used to develop more optimized age-related guidance on 99mTc-MDP administered activities to children.

Reference values of mandibular condyles metabolic activity: A study using 99m Tc-MDP single-photon emission computed tomography.

To assess the condylar bone metabolic activity in patients with temporomandibular joint health by measuring 99m Tc-MDP uptake using a single-photon emission computed tomography (SPECT) to establish reference values of the uptake difference between condyles and the ratio with respect to the clivus. Eighty consecutive patients of both sexes who were admitted to a Nuclear Medicine Centre between 2017 and 2019 were included in the study. This was an observational cross-sectional study in patients with SPECT indications to evaluate pathologies other than those of the temporomandibular joint. The values of the total and normalized counts in a fixed region of interest of five trans-axial slides were obtained to assess the percentage difference between the sides and the uptake ratio. The reference values are expressed as median and 5th and 95th percentiles. The sample included 53 women (66.25%) and 27 men (33.75%) aged 15-55years. The percentage of uptake difference between condyles was 5.04% (0.46-14.78) for men and 5.17% (0.27-13.21) for women (difference not significant, P=.9). The uptake difference was below 10% in 85% of the subjects (n=68). The ratio values for total counts in women (0.87, 0.46-1.33) were significantly different (P=.0030) from those in men (1.08, 0.61-2.09). No significant correlation with age was found. These new reference ranges are applicable to the diagnosis of unilateral and bilateral condylar hyperplasia.

Incidental finding of elevated 99mTc-MDP uptake in a large renal lithiasis

Incidental finding of elevated 99mTc-MDP uptake in a large renal lithiasis

The Value of 99mTc-Methylene Diphosphonate Single-Photon Emission Computed Tomography/Computed Tomography in Detecting Atraumatic Costal Cartilage Fracture in Malignant Tumor Patients.

Objectives: To assess the clinical significance and single-photon emission computed tomography/computed tomography (SPECT/CT) features of atraumatic costal cartilage fracture (CCF) in patients with malignant tumors.Methods: This was a retrospective review of 38 tumor patients with atraumatic CCF referred to SPECT/CT, who were served as the study group (SG). The features of SPECT/CT of atraumatic CCF were assessed. Another 100 tumor patients who underwent chest SPECT/CT and did not have CCF were randomly selected as the control group (CG). In all patients (SG + CG), the diagnostic powers in the detection of atraumatic CCF were computed among CT, SPECT, and SPECT/CT. The final diagnosis was based on pathological findings and radiologic follow-up of at least 1 year.Results: On SPECT/CT images of atraumatic CCF in the SG, fracture lines, irregular calcification, deformation, and swelling were, respectively, noted in 26.3, 47.4, 34.2, and 18.4% of lesions; low, moderate, and high uptake were, respectively, noted in 13.2, 52.6, and 34.2% of lesions. In all patients (SG + CG), the diagnostic powers in the detection of atraumatic CCF of CT, SPECT, and SPECT/CT were as follows: sensitivity 63.2, 100.0, and 92.1%; specificity 86.0, 81.0, and 94.0%; negative predictive value 86.0, 100.0, and 96.9%; positive predictive value 63.1, 66.7, and 85.4%; and area under the curve value 0.746, 0.905, and 0.931.Conclusions: Atraumatic CCF has certain characteristic appearances on SPECT/CT. It should be enrolled in the differential diagnoses when costal cartilages of patients with malignant tumors show abnormal elevated 99mTc-MDP uptake on scintigraphy. Single-photon emission computed tomography/CT has excellent diagnostic power in detecting atraumatic CCF.

Positive Myocardial Uptake of Bone Scintigraphic Agents Associated with Cardiac Amyloidosis: Frequency of Positive Uptake Data Based on Daily Clinical Practice

Objective: The bone scan plays an important role for detecting number of conditions relating to bones, including: bone cancer or bone metastasis, bone inflammation. Extraosseous uptake, in particular, myocardial uptake, was observed in some patients examined with the bone scans. Positive uptake of 99mTc-labeled bone radiotracers is associated with cardiac amyloidosis. However, the frequency and cause of positive cardiac 99mTc-MDP uptake have not been fully studied. In this regard, the aim of this study was to assess the frequency and characteristics of patients with high myocardi-al uptake of bone scintigraphy in daily clinical practice setting. Methods: We retrospectively analyzed 4180 bone scintigraphies performed in daily clinical practice during 7-years period. The intensity of the myocardial uptake was graded based on a visual scale ranging from 0 to 3 points. Score 0 indicates the absence of uptake. Score 1 defined uptake less than that of bone (referred to as the adjacent rib). Uptake similar to that of bone was classified score 2. Score 3 was defined as uptake greater than that of reference bone. Positive myocardial uptake included a visual score 2 or 3. Result: Positive 99mTc-MDP myocardial uptake occurred in 12 patients among 4180 patients (0.3%). 7 of 12 positive scan patients were consistent with amyloidosis confirmed by biopsy. In these patients, the mean age was 75.6 ± 5.2 years old. Ten cases showed biventricular uptake and 2 showed LV uptake only. Conclusion: Positive cardiac uptake of bone scintigraphic agents was present in 0.3% of bone scintigraphies in a clinical practice setting. This may be a sign of cardiac amyloidosis involvement which may give the presence of extraosseous bone tracer uptake its own importance and a new role.

Maximum standardized uptake value from quantitative bone single-photon emission computed tomography/computed tomography in differentiating metastatic and degenerative joint disease of the spine in prostate cancer patients.

Qualitative interpretation in bone scan is often complicated by the presence of degenerative joint disease (DJD), especially in the elderly patient. The aim of this study is to compare objectively 99mTc-MDP tracer uptake between DJD and osseous metastases of the spine using semi-quantitative assessment with SPECT SUV. Bone scan with SPECT/CT using 99mTc-MDP was performed in 34 patients diagnosed with prostate carcinoma. SPECT/CT was performed based on our institutional standard guidelines. SUVmax based on body weight in 238 normal vertebrae visualized on SPECT/CT was quantified as baseline. A total of 211 lesions in the spine were identified on bone scan. Lesions were characterized into DJD or bone metastases based on its morphology on low-dose CT. Semi-quantitative evaluation using SUVmax was then performed on 89 DJD and 122 metastatic bone lesions. As most of the bone lesions were small in volume, the effect of partial volume effect (PVE) on SUVmax was also assessed. The corrected SUVmax values were obtained based on the recovery coefficient (RC) method. The mean SUVmax for normal vertebrae was 7.08 ± 1.97, 12.59 ± 9.01 for DJD and 36.64 ± 24.84 for bone metastases. The SUVmax of bone metastases was significantly greater than DJD (p value < 0.05). To assess for diagnostic accuracy, receiver operating characteristic (ROC) curve was performed. The area under the curve (AUC) was found to be fairly high at 0.874 (95% CI 0.826-0.921). The cutoff SUVmax value ≥ 20 gave a sensitivity of 73.8% and specificity of 85.4% in differentiating bone metastases from DJD. The corrected SUVmax for both DJD and bone metastases was smaller with a mean of 6.82 ± 6.02 and 24.77 ± 20.61, respectively. The cutoff SUVmax value was also lower with a value of 10, which gave a sensitivity of 73.8% and specificity of 86.5%. SPECT SUVmax was significantly higher in bone metastases than DJD. Semi-quantitative assessment with SUVmax can complement qualitative analysis. A cutoff SUVmax of ≥ 20 can be used to differentiate bone metastases from DJD. Partial volume effect should be taken into consideration in the quantification of small lesion size.

Diagnostic value and clinical significance of abnormal uptake in extraosseous tissue for differentiating benign from malignant lesions

Objective To investigate the regularity and clinical significance of abnormal bone uptake of 99Tcm-methylene bisphosphonate (MDP) in benign and malignant lesions. Methods A retrospective analysis was performed on 266 patients (132 males, 134 females, age range: 8-85 years) with abnormal uptake of 99Tcm-MDP in extraosseous tissues from September 2015 to March 2018. The final diagnosis of abnormal uptake was made according to the histopathology, laboratory and related imaging examination (CT, MRI, ultrasound, SPECT/CT or PET/CT imaging) results within 2 weeks after 99Tcm-MDP imaging. Regularity of abnormal 99Tcm-MDP uptake was comprehensively analyzed. Differences between benign and malignant groups were compared by χ2 test or Fisher exact test. Results Abnormal 99Tcm-MDP uptake in extraosseous tissues in 232 patients (87.2%, 232/266) were confirmed as malignant lesions and those in 34 patients (12.8%, 34/266) were benign. There were no significant differences in gender (χ2=0.611, P>0.05), age (P=0.584), and location (P=0.118) between benign and malignant lesions, but the involvement was significantly different (χ2=19.515, P<0.05). There were significant differences between single focus and diffuse foci of single organ, diffuse foci of single organ and multiple foci groups (χ2=8.959, 19.325, both P<0.01). Conclusions The detection rate of malignancy among foci with abnormal 99Tcm-MDP uptake in extraosseous tissues is high, and the malignancy may relate with the involvement of foci. When extraosseous uptake is found, clinical information and related examination results should be comprehensively analyzed and the malignancy should be taken into account. Key words: Skeleton; Neoplasms; Diagnosis, differential; Tomography, emission-computed, single-photon; Tomography, X-ray computed; Technetium Tc 99m medronate

Characterization of Solitary Lesions in the Extremities on Whole-Body Bone Scan in Patients With Known Cancer: Contribution of Single-Photon Emission Computed Tomography/Computed Tomography.

Background: Solitary lesions in the extremities showing 99mTc-methylene diphosphate (MDP) uptake are often encountered on whole-body bone scan (WBS), and proper interpretation of this diagnostic method is important for patients with known cancer. The purpose of this study was to summarize the characteristics of solitary lesions in the extremities of patients with known cancer and to evaluate the diagnostic accuracy of single-photon emission computed tomography/computed tomography (SPECT/CT) in differentiating bone metastases from benign bone lesions.Methods: This study was a retrospective review of 86 patients (54 males and 32 females; mean age, 57.88 ± 10.97 years; range, 31–81 years) with known cancer who underwent WBS and showed solitary lesions with 99mTc-MDP uptake in the extremities and then underwent SPECT/CT for further diagnosis. SPECT/CT images were independently interpreted by two experienced nuclear medicine physicians. The diagnostic accuracy of SPECT/CT in differentiating malignant from benign solitary lesions in the extremities was evaluated. Inter-reviewer agreement was assessed by using weighted k statistics. The standard diagnostic criterion was based on biopsy or radiologic follow-up over at least 12 months.Results: In total, 23 bone metastases and 63 (73.26%) benign lesions were diagnosed. The majority (16/23, 69.57%) of bone metastases were found in the diaphyses. The most common benign bone disease was a benign bone tumor (31.75%, 20/63). The majority (13/20, 65%) of benign bone tumors were enchondromas. In the proximal and distal extremities, the most common disease was degeneration (27.11%, 16/59), followed by benign bone tumors and osteonecrosis of the femoral head (ONFH) (22.03%, 13/59). In the diaphyses of the extremities, bone metastasis was the most common disease, accounting for 64% (16/25) of the findings. For the SPECT/CT analysis, the accuracy was 94.19% (81/86) for reviewer 1 and 95.34% (82/86) for reviewer 2. The weighted kappa score for inter-reviewer agreement was 0.813.Conclusion: When solitary disease of the extremities is detected by WBS in patients with known cancer, benign lesions may be more common than malignant lesions. SPECT/CT resulted in not only fewer equivocal lesions but also in higher diagnostic accuracy.

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

Background99mTc-labelled methylene diphosphonate (99mTc-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 99mTc-MDP uptake in extraosseous neoplasms and to assess the additional value of SPECT/CT for the localization and characterization of this unusual uptake.MethodsData 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 99mTc-MDP uptake were evaluated by WBS, and the intratumoural calcification was evaluated by SPECT/CT. The diagnostic accuracy of SPECT/CT in locating 99mTc-MDP uptake in extraosseous neoplasms was compared to that of WBS.ResultsA total of 41 patients showed 99mTc-MDP uptake in extraosseous neoplasms. Of these patients, 23 patients had uncertain lesions by WBS, and further SPECT/CT was performed. The incidence of 99mTc-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 99mTc-MDP uptake. Of the 23 patients, 17 patients (73.9%, 18/23) with 31 lesion sites (77.5%, 31/40) presented with intratumoural calcification.Conclusions99mTc-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.