Calf “Arch Sign” Seen on a Tc-99m-MDP Bone Scan Is Indicative of Synovial Fluid Leak in Ruptured Baker's Cysts: Case Reports and Analysis of Literature / 대한핵의학회잡지

The authors present two cases in which the ruptured popliteal (Baker's) cysts remained undetected and were diagnosed only during an isotope investigation. The aim was to describe a specific imaging sign, the “arch sign”, that is indicative of ruptured Baker's cysts. In both cases, the whole-body imaging was performed 2 hours after injection of 706.7 MBq of Tc-99m-MDP. Single-photon emission computed tomography (SPECT) imaging was performed to localize an accumulation of the radiopharmaceutical. An analysis of literature was performed to connect these cases with previously reported data and to detect the pathognomonic radio image sign of ruptured popliteal cysts. The arch-shaped distribution of the radiopharmaceutical below the knee joints was seen already on the whole-body bone scan image in both cases. An anterior view of SPECT MIP images showed the arched accumulation of the Tc-99m-MDP bone tracer along the postero-medial aspect of the right calf secondary to synovial fluid leak from a ruptured Baker's cyst. The similar arthroscintigrams were published since 1971 without recognizing this sign as pathognomonic. Tc-99m-MDP bone scanning is sensitive for a Baker's cyst with synovial effusion, and distribution of a radiopharmaceutical in the medial posterior calf in a shape of an arch, the arch sign, may serve as an indicator of a ruptured popliteal cyst.

Incidental Visualization of Thyroid Gland on Bone Scan Caused by Graves' Hyperthyroidism / 핵의학분자영상

A 45-year-old man presented with fatigue and weight loss underwent a Tc-99m MDP bone scan because of increased serum alkaline phosphatase. Delayed images at 4 hours demonstrated diffuse increased activity throughout both lobes of the thyroid in the absence of activity of the stomach and salivary glands. Thyroid laboratory indices and a Tc-99m pertechnetate thyroid scan suggested Graves' hyperthyroidism.

Ga-67 Citrate and Tc-99m MDP Uptake in the Lung and Stomach Associated with Hypercalcemia / 핵의학분자영상

Ga-67 scintigraphy demonstrated increased uptake in the lungs and stomach in a 26-year-old man with hypercalcemia. A primitive neuroectodermal tumor was confirmed by bone marrow examination. Tc-99m MDP uptake in the same locations as Ga-67 revealed by bone scintigraphy was consistent with metastatic calcification. Although the mechanism of Ga-67 uptake in metastatic calcification is not understood, the presence of an inflammatory process is suggested.

Tc-99m MDP-induced Acute Hepatitis in a Hemodialysis Patient / 대한신장학회지

Bone scan is one of the most frequently performed studies in nuclear medicine with few adverse reactions for the examination of pathologic conditions of bone. Diffuse liver uptake of Technetium-99m methylene diphosphonate (Tc-99m MDP) is a rare occurrence with only a few reports in the literature. Furthermore, there is no report of Tc-99m MDP-induced liver injury. Here we report a case of acute hepatitis with diffusely increased uptake of Tc-99m MDP in a hemodialysis patient.

Multifocal Calcifications of the Falx Cerebri and Dura Presenting as Hot Spots in the Skull on Bone Scintigraphy / 핵의학분자영상

A 49-year-old woman with invasive ductal carcinoma of the right breast underwent Tc-99m MDP bone scintigraphy for an evaluation of skeletal metastases. Multiple focal hot spots in the midline and left frontoparietal skull region were observed. The plain radiographs revealed the typical findings of the calcification of the falx cerebri and dura. These findings might be mistaken for metastases of the skull in cancer patients. Therefore, a radiographic correlation is essential when multifocal hot spots in the skull are observed in cancer patients.

Biparietal Thinning Showing Typical Bilateral Photon Defects on Bone Scintigraphy and SPECT / 핵의학분자영상

A 68-year-old man with small cell carcinoma of the lung and adenocarcinoma of the prostate underwent Tc-99m MDP bone scintigraphy for the evaluation of skeletal metastases. Bilateral symmetrical photon defects in both parietal bones of the skull were observed. The radiographs of the skull demonstrates biparietal thinning in the same area of the abnormality identified on bone scintigraphy. Although these findings in cancer patients can be mistaken for skeletal metastases, the symmetry and location of the photon defects are generally indicative of biparietal thinning.

Useful Lateral Views of Sacrococcygeal Region in Skeletal Scintigraphy / 대한핵의학회잡지

A tail-on-detector (TOD) view has been used to see the symphysis pubis or sacrococcyx in skeletal scintigraphy, but it is inconvenient to acquire because a patient must sit or lean on a detector. The TOD views are still frequently performed in training hospitals in Korea, although it is becoming almost impossible to sit on a camera in this age of dual-headed cameras. The authors show cases with lateral views obtained in supine position that were acquired for the same reason; they are easier and more useful than the TOD views.

Normal Variants and Artifacts in Bone Scan: Potential for Errors in Interpretation / 대한핵의학회잡지

Bone scan is one of the most frequently performed studies in nuclear medicine. In bone scan, the amount of radioisotope taken up by lesion depends primarily on the local rate of bone turnover rather than on the bone mass. Bone scan is extremely sensitive for detecting bony abnormalities. However, abnormalities that appear on bone scan may not always represent disease. The normal scan appearances may be affected not only by skeletal physiology and anatomy but also by a variety of technical factors which can influence image quality. Many normal variants and artifacts may appear on bone scan. They could simulate a pathologic process and could mislead into the wrong diagnostic interpretation. Therefore, their recognition is necessary to avoid misdiagnosis. A nuclear medicine physician should be aware of variable appearance of the normal variants and artifacts on bone scan. In this article, a variety of normal variants and artifacts mimicking real pathologic lesion in bone scan interpretation are discussed and illustrated.

The Usefulness of Measurement of Whole Body Count in Assessing Bone Marrow Metastasis in Cancer Patients with Increased Periarticular Bone Uptake on Follow-up Bone Scan: A Comparison with Bone Marrow Scan / 대한핵의학회잡지

PURPOSE: Increased periarticular uptake could be associated with peripheral bone marrow expansion in cancer patients with axial bone marrow metastasis. We compared bone scan and bone marrow scan to investigate whether the increased whole body count in patients with increased periarticular uptake on bone scan is useful in the diagnosis of axial marrow metastasis, and evaluate the role of additional bone marrow scan in these cases. MATERIALS AND METHODS: Twelve patients with malignant diseases who showed increased periarticular uptake on bone scan were included. Whole body count was measured on bone scan and it is considered to be increased when the count is more than twice of other patients. Bone marrow scan was taken within 3-7 days. RESULTS: Five hematologic malignancy, 3 stomach cancer, 2 breast cancer, 1 prostate cancer and 1 lung cacner were included. All three patients with increased whole body count on bone scan showed axial marrow suppression and peripheral marrow expansion. Eight of 9 patients without increased whole body count showed axial marrow suppression and peripheral marrow expansion. One turned out to be blastic crisis of chronic myelogeneous leukemia, and seven showed normal axial marrow with peripheral marrow expansion in chronic anemia of malignancy. The last one without increased whole body count showed normal bone marrow scan finding. CONCLUSION: Increased whole body count on bone scan could be a clue to axial bone marrow metastasis in cancer patients with increased periarticular uptake, and bone marrow scan is a valuable method for differential diagnosis in these cases.

Fibrous Dysplasia Associated with Primary Hyperparathyroidism Absent of McCune-Albright Syndrome: Tc-99m MIBI and Tc-99m MDP Findings / 대한핵의학회잡지

No abstract available.

Osteogenic Sarcoma with Osseous, Pulmonary, and Pericardial Metastases Simultaneously Demonstrated on Bone Scintigraphy at Initial Presentation / 대한핵의학회잡지

PURPOSE: A 6-year-old boy with osteogenic sarcoma of the left humerus underwent bone scintigraphy. Tc-99m MDP was accumulated not only in the primary tumor but also in the osseous and extraosseous (pulmonary and pericardial) metastases. Osteogenic sarcoma directly produces osteoid, both in the primary and metastatic lesions. Tc-99m MDP is avidly taken up by tumor osteoid. At initial presentation, only 2% of cases have both pulmonary and osseous metastases. The patient had osseous, pulmonary, and pericardial metastases at presentation. This case presents that increased uptakes of Tc-99m MDP by the primary and metastatic tumor were demonstrated on bone scintigraphy at presentation.

Role of Bone Scan in Rheumatic Diseases / 대한핵의학회잡지

Rheumatic diseases can be categorized by pathology into several specific types of musculoskeletal problems, including synovitis (e.g. rheumatoid arthritis), enthesopathy (e.g. ankylosing spondylitis) and cartilage degeneration (e.g. osteoarthritis). Skeletal radiographs have contributed to the diagnosis of these articular diseases, and some disease entities need typical radiographic changes as a factor of the diagnostic criteria. However, they sometimes show normal radiographic findings in the early stage of disease, when there is demineralization of less than 30-50 %. Bone scans have also been used in arthritis, but not widely because the findings are nonspecific and it is thought that bone scans do not add significant information to routine radiography. Bone scans do however play a different role than simple radiography, and it is a complementary imaging method in the course of management of arthritis. The image quality of bone scans can be improved by obtaining regional views and images under a pin-hole collimator, and through a variety of scintigraphic techniques including the three phase bone scan and bone SPECT. Therefore, bone scans could improve the diagnostic value, and answer multiple clinical questions, based on the pathophysiology of various forms of arthritis.

Cerebral Infarction Mimicking Skeletal Metastases on Tc-99m MDP Bone Scintigraphy / 대한핵의학회잡지

A 60-year-old male with carcinoma of the prostate and cerebral infarction underwent a Tc-99m MDP bone scintigraphy for the evaluation of skeletal metastases. Bone scintigraphy (Fig. 1) showed multiple areas of increased uptake of Tc-99m MDP in the skull, spine, and ribs representing skeletal metastases. Two different patterns of uptake occurred in the skull region (Fig. 1A-C); one represents bony metastasis and the other represents cerebral infarction. The shape, size, location, intensity, and border of the increased uptake differed between the two lesions. An oval-shaped pattern with smaller size, greater intensity and more sharply defined border in the frontal region was consistent with bony metastasis. A rectangular-shaped pattern with larger size, lesser intensity and relatively indistinct border in the temporo-parieto-occipital region was consistent with cerebral infarction. Increased uptake of bone-seeking radiotracers in cerebral infarction has been reported previously.1-4) A suggested mechanism by which bone-seeking radiotracers accumulate in the necrotizing cerebral tissue is an alteration of the blood-brain barrier induced during cerebral infarction, which results in entry of the radiotracers into the extracellular space of the brain.4) Brain CT (Fig. 2) performed 7 days before and one month after the bone scintigraphy revealed lesions on the right temporo-parieto-occipital region consistent with acute hemorrhagic and chronic cerebral infarction, respectively.

Unusual Tc-99m MDP Uptake in the Keloid Developed after Subtotal Gastrectomy / 대한핵의학회잡지

A 63-year-old male who had subtotal gastrectomy for early gastric cancer three months ago underwent Tc-99m bone scintigraphy for the evaluation of skeletal metastases. He had no symptoms such as fever, tenderness, or wound discharge. On physical examination, the surgical scar along the midline of the upper abdomen had keloid formation and there was no radiographic evidence of calcification. Bone scintigraphy (Fig. 1A & 1B) demonstrated an unusual linear increased uptake along the midline of the upper abdomen that corresponded to the skin incision for subtotal gastrectomy. Usually, an incisional scar will not be visualized in Tc-99m methylene diphosphate (MDP) scintigraphy beyond two weeks after surgery.1) Upon reviewing the literature, there were only a few reports where localization of Tc-99m MDP in surgical scars were found two months after surgery.2) It was also reported that a few cases with Tc-99m MDP uptake in the keloid scar developed after surgery. Although there are several potential mechanisms that may explain the uptake of Tc-99m MDP in scar tissue, the primary mechanism in older scars is suggested to be a result of pathological calcification.2) Siddiqui et al3) suggested it could be due to microscopic calcification in small resolving hematomas. However, the primary mechanism in keloid scar is not well-known. We should obtain oblique or lateral views to differentiate the uptake in healing surgical scars from the artifactual uptake.

Acute Osteomyelitis Shown as a Cold Lesion on Bone Scan / 대한핵의학회잡지

Acute osteomyelitis is usually shown as a localized area of increased activity (hot uptake) in the infectious focus on bone scintigraphy. In our patient, absence of radioactivity (cold lesion) was noted in the distal metaphyseal and diaphyseal regions of his right femur. Initial x-ray was interpreted as normal except for mild soft tissue swelling in the right thigh. The lesion was confirmed as an acute osteomyelitis with subperiosteal abscess on surgery. Staphylococcus aureus was the etiologic organism. We describe a case of acute osteomyelitis in a one-year-old boy shown as a cold lesion on bone scan.

The Usefulness of Postoperative Pinhole Bone Scintigraphy in the Assessment of Prognosis after Multiple Drilling or Vascularized Bone Graft in Patients with Avascular Necrosis of Femoral Head / 대한핵의학회잡지

PURPOSE:It is important to evaluate the healing process of avascular necrosis (AVN) involving femoral head after treatment. The purpose of this study was to assess the usefulness of pinhole bone scintigraphy in the AVN of femoral head after surgery. MATERIALS AND METHODS: We analyzed the changing pattern of pinhole bone scintigram in 21 femoral heads of 16 patients (14 lesions/11 male, 7 lesions/5 female, mean age: 39.4 yrs) before and after multiple drilling or vascularized bone grafting for AVN of the femoral head. In all patients, pre-operative scintigrams were obtained at 1 to 3 months before treatment and the first post-operative scintigrams were obtained at 1 to 3 months after treatment. All patients were followed for 2 to 4 years after operation. RESULTS: The findings of the pinhole scintigrams were divided into three patterns: 1) curvilinear, 2) scattered spotty and 3) undetermined. The 10 of 11 lesions with curvilinear pattern had good postoperative clinical and radiological follow-up findings. However, all 6 lesions with scattered spotty pattern showed poor postoperative findings, which necessitated total hip joint replacement. Of the 4 lesions with undetermined pattern, 2 required total hip joint replacement. There was significant difference in postoperative prognosis between the curvilinear and scattered spotty patterns (p<0.05). CONCLUSION: We conclude that the pattern of pinhole bone scintigram obtained within 1 to 3 months after multiple drilling or vascularized bone graft operation is a useful prognostic indicator in the AVN of femoral head.

Assessment of Vascularization within Hydroxyapatite Ocular Implant by Bone Scintigraphy: Comparative Analysis of Planar and SPECT Imaging / 대한핵의학회잡지

PURPOSE: Complete fibrovascular ingrowth within the hydroxyapatite ocular implant is necessary for peg drilling which is performed to prevent infection and to provide motility to the ocular prosthesis. We compared planar bone scintigraphy and SPECT for the evaluation of the vascularization within hydroxyapatite ocular implants. MATERIALS AND METHODS: Seventeen patients (M:F=12:5, mean age: 50.4+/-17.5 years) who had received a coralline hydroxyapatite ocular implant after enucleation surgery were enrolled. Patients underwent Tc-99m MDP planar bone and SPECT imaging by dual head gamma camera after their implant surgery (interval: 197+/-81 days). Uptake on planar and SPECT images was graded visually as less than (grade 1), equal to (grade 2), and greater than (grade 3) nasal bridge activity. Quantitative ratio of implanted to non-implanted intraorbital activity was also measured. Vascularization within hydroxyapatite implants was confirmed by slit lamp examination and ocular movement. RESULTS: All but three patients were considered to be vascularized within hydroxyapatite implants. In visual analysis of planar image and SPECT, grade 1 was noted in 9/18 (50%) and 6/18 (33%), respectively. Grade 2 pattern was 7/18 (39%) and 4/18 (22%), and grade 3 pattern was 2/18 (11%) and 8/18 (44%) respectively. When grade 2 or 3 was considered to be positive for vascularization, the sensitivity of planar and SPECT imaging were 60% (9/15) and 80% (12/15), respectively. In 3 patients with incomplete vascularization, both planar and SPECT showed grade 1 uptake. The orbital activity ratios on planar imaging were not significantly different between complete and incomplete vascularization (1.96+/-0.87 vs 1.17+/-0.08, p>0.05), however, it was significantly higher on SPECT in patients with complete vascularization (8.44+/-5.45 vs 2.20+/-0.87, p<0.05). CONCLUSION: In the assessment of fibrovascular ingrowth within ocular implants by Tc-99m MDP bone scintigraphy, SPECT image appears to be more effective than planar scintigraphy.

Differentiation of Bone Metastases and Fractures using 24 hour / 3 hour Radio-uptake Ratio in Bone Scintigraphy / 대한핵의학회잡지

PURPOSE: We evaluated the usefulness of 24 hour/3 hour radio-uptake ratio, lesion to non-lesion ratio, in differentiating bony metastases from acute (<2 months) and healing ( 2 months) fractures. MATERIALS AND METHODS: Sixty-three patients (age range: 26-81, 32 males, 31 females) having 90 lesions (30 bone metastases, 30 acute fractures, 30 healing fractures) were included. Bone scans were obtained 3 and 24 hours after administration of 740 MBq of 99mTc-MDP. The ratio of radio-uptake in the lesion to normal area was measured as 24/3 hour radio-uptake ratio ([lesion/non-lesion RUR at 24 hour]/[lesion/non-lesion RUR at 3 hour], 24/3 RUR) and analyzed clinical significance in differentiating bone metastases from acute or healing fractures. RESULTS: Mean 24/3 RUR were 1.22+/-0.18 for bone metastases, 1.25+/-0.14 for acute fractures, and 0.99+/-0.15 for healing fractures. 24/3 RUR values of bone metastases and acute fractures were not significantly different. But 24/3 RUR values of bone metastases and healing fractures, and those of acute and healing fractures were found to be significantly different (p<0.001). When 24/3 RUR of 1.0 was considered as the cut off point separating metastases from fracture, a sensitivity of 100% (30/30) was obtained. The specificity was 0% (0/30) in separating metastases from acute fractures, and 47% (14/30) in separating metastases from healing fractures. When 24/3 RUR of 1.2 was considered as the cut off point, sensitivity of 53% (16/30) in the diagnosis of bone metastasis, and specificity of 37% (11/30) in separating metastases from acute fractures, and 100% (30/30) in separating metastases from healing fractures were obtained. CONCLUSION: 24/3 RUR is useful in differentiating bone metastases from healing fractures, but not in differentiating bone metastases from acute fractures. A 24/3 RUR of less than 1.0 suggests healing fractures. A 24/3 RUR of more than 1.2 suggests bone metastases or acute fractures.

Clinical Study on Early Diagnosis of Skeletal Disorders by Bone Scan with Tc-99m-MDP (Medronate) / 대한정형외과학회잡지

Early detection of skeletal disorders was very important role in establishing therapeutic modality and prevention of complications. Since Tc-99m-phosphates derivatives used in bone scan agent, remarkable improvement was noted in effectiveness, cost, radiation hazard to patient and image quality than previously used agents such as strontium or fluoride. Bone scan with Tc-99m-MDP was done in 155 cases for early diagnosis of skeletal disorders at Severance Hospital, College of Medicine, Yonsei University from August, 1980 to May, 1982 were analyzed both clinically and radiologically, and the following results were obtained. l. Among 19 cases of avascular necrosis, positive cases were 17 (89.5%) in bone scan and 6(31.6%) in X-ray. Positive pattern could be classified into 3 types and the radionuclide uptake in the femoral head was decreased in 3 cases which was negative in X-ray and duration of their symptoms was within 4 months. 2. Fifteen among 17 hip fractures or dislocations were positive in bone scan. In 12 (80.0%) among 15 cases, complications were revealed and positive cases in X-ray were 7(58.3%), which were all positive in bone scan. 3. In 20 bone scans for early diagnosis of acute osteomyelitis, positive in bone scan were 17 and 14 (82.4%) of 17 cases were finally diagnosed as acute osteomyelitis. Among 15 cases diagnosed as acute osteomyelitis, positive in X-ray were 8(53.3%) and sensitivity of acute osteomyelitis in bone scan was 93.3%. 4. In 25 cases of the suspected infection of the joint, 15 were positive in bone scan and among them, cases diagnosed as pyogenic arthritis were 12 (80.0%) and positive in X-ray were 2 (16.7%). Only one of 10 cases of transient synovitis of the hip joint was positive in bone scan. 5. In rheumatoid arthritis, 13 of 15 cases were positive in bone scan and 10 among them were revealed the diffuse uptake of the radionuclide in the joint. In degenerative arthritis, 7 of 8 cases were positive in bone scan and they were revealed the focal uptake of the radionuclide in the same site where the bone was changed in x-ray. 6. Among 28 cases showed spine fracture in X-ray after trauma, 15 (53.6%) were positive in bone scan. In spine fracture, it was difficult to differentiate fresh fracture from old fracture with bone scan. The positive duration of bone scen in fracture of weight bearing bone was longer than in spine fracture. Rib fracture which was not found in X-ray could be diagnosed with bone scan.