Showing papers in "Clinical Nuclear Medicine in 2000"
TL;DR: FDG PET is a highly effective imaging method to exclude osteomyelitis when a negative scan result is obtained, however, positive results can be caused not only by true osteomyeitis but also by inflammation in the bone or surrounding soft tissues as a result of other causes.
Abstract: Purpose:Excluding the diagnosis of chronic osteomyelitis is often difficult with noninvasive techniques, especially when bone anatomy and structure have been altered by trauma, surgery, or soft-tissue infection. It has been reported that fluorodeoxyglucose (FDG) positron emission tomography (PET) ha
187 citations
TL;DR: Combined PET–CT images appear more effective than PET images alone to localize precisely neoplastic lesions and to distinguish normal variants from juxtaposed neoplastics lesions.
Abstract: Purpose To compare combined whole-body PET and CT images of different cancers with PET images alone. Materials and methods Thirty-two patients with known or possible cancers were examined using a combined positron emission tomographic (PET) and computed tomographic (CT) scanner. All data were acquired using this same combined scanner. After an injection of F-18 fluorodeoxyglucose (FDG), noncontrast helical CT imaging of the neck, chest, abdomen, or pelvis was performed. The spiral CT was followed by a PET scan covering the same axial extent as the CT. Results Coregistered PET-CT images identified and localized 55 lesions. In 10 patients (31%), areas with variable amounts of normal physiologic FDG uptake were distinguished from potential uptake of FDG in a nearby neoplastic lesion. Improved localization was achieved in 9 patients (for a total of 13 lesions, or 24%). Conclusion Combined PET-CT images appear more effective than PET images alone to localize precisely neoplastic lesions and to distinguish normal variants from juxtaposed neoplastic lesions.
174 citations
TL;DR: Pulmonary infection or inflammation might predispose patients to localized F-18 FDG chest uptake mimicking pulmonary metastases and limiting the specificity of whole-body scans performed in patients with cancer.
Abstract: Purpose F-18 fluorodeoxyglucose (FDG) may accumulate at sites of inflammation or infection, making interpretation of whole-body scans difficult in patients with cancer. Methods More than 650 whole-body positron emission tomographic (PET) scans performed to examine patients with cancer were reviewed to identify uptake in pulmonary infection or inflammation based on the appearance of F-18 FDG chest uptake, chest radiographs, computed tomography, or all of these. Results Ten patients had uptake in benign lung disease. Eight patients had head and neck tumors and two patients had breast cancer. Intense focal or multifocal F-18 FDG chest uptake was seen in 6 of 10 scans. This was difficult to distinguish from pulmonary metastases based on the scan appearance. However, in the remaining patients, the uptake was atypical for malignancy and displayed an apical, segmental, or lobar pattern. In all patients, the F-18 FDG lung uptake corresponded to benign radiologic changes (infiltration, consolidation, or atelectasis), and the final diagnosis was pulmonary inflammation or infection. Nine patients were asymptomatic and one patient had clinical aspiration pneumonia. Follow-up PET scans were performed in five patients to evaluate their conditions. Chest uptake disappeared completely in three patients and partially in two patients, and there were no new findings. Variable degrees of F-18 FDG chest uptake have been reported with more than 40 different benign causes. They can be classified based on the underlying mechanism into four major categories: 1) Inflammation or infection, 2) benign tumor, 3) physiologic activity, and 4) iatrogenic. Most of these false-positive cases are included in the first category. Conclusions Pulmonary infection or inflammation might predispose patients to localized F-18 FDG chest uptake mimicking pulmonary metastases and limiting the specificity of whole-body scans performed in patients with cancer.
165 citations
TL;DR: FDG PET seems to be a promising tool for evaluating the response of primary osseous tumors to chemotherapy, and in this preliminary study, FDG PET was superior to planar bone scintigraphy.
Abstract: Purpose The purpose of this study was to evaluate the potential of positron emission tomography using F-18-fluoro-2-deoxy-D-glucose (FDG PET) to assess the chemotherapy response of primary osseous tumors compared with the degree of necrosis determined histologically. Patients and Methods Seventeen patients with primary bone tumors (11 osteosarcomas, 6 Ewing’s sarcomas) were examined using FDG PET and planar bone scintigraphy before neoadjuvant chemotherapy and before surgery. Tumor response was classified histologically according to Salzer-Kuntschik (grades I–III: good response; grades IV–VI: poor response). In both imaging methods, quantification was performed using tumor to nontumor ratios (T:NT). Results Histologically, 15 patients were classified as having good responses (grade I, n = 1; grade II, n = 6; grade III, n = 8) and two as having poor responses (grades IV and V). FDG PET showed more than a 30% decrease in T:NT ratios in all patients who had good responses. However, three of these patients had increasing bone scintigraphy T:NT ratios, and another five had decreasing ratios of less than 30%. The patients with poor responses had increasing T:NT ratios and decreasing ratios of less than 30%, respectively, using both imaging methods. Conclusions FDG PET seems to be a promising tool for evaluating the response of primary osseous tumors to chemotherapy. In this preliminary study, FDG PET was superior to planar bone scintigraphy.
148 citations
TL;DR: The relatively low sensitivity of PET for identifying locoregional lesions precludes its replacement of conventional CT staging, and the primary advantage of PET imaging is its superior specificity for tumor detection and improved diagnostic value for distant metastatic sites.
Abstract: Purpose The aim of the authors in this study was to critically evaluate the role of whole-body positron emission tomographic (PET) imaging with fluorine-18 fluorodeoxyglucose (FDG) in staging esophageal cancer, and further to compare this method with conventional imaging with computed tomography (CT). Materials and methods The authors performed independent, blinded retrospective evaluations of FDG PET images obtained in 47 patients referred for the initial staging of esophageal cancer before minimally invasive surgical staging. Twenty PET studies from patients with nonesophageal thoracic cancers were randomly selected for inclusion in the PET readings. In a subset of 37 of 47 cases, the PET findings were compared with independent readings of CT studies acquired within the same 6-week interval. The utility of the imaging findings was evaluated using a high-sensitivity interpretation (i.e., assigning equivocal findings as positive) and a low-sensitivity interpretation (i.e., assigning equivocal findings as negative). Results PET was less sensitive (41% in high-sensitivity mode, 35% in low-sensitivity mode) than CT (63% to 87%) for diagnosing tumor involvement in locoregional lymph nodes, which was identified by surgical assessment in 72% of patients. Notable, however, was the greater specificity of PET-determined nodal sites (to approximately 90%) compared with CT (14% to 43%). In detecting histologically proved distant metastases (n = 10), PET performed considerably better when applied in the high-sensitivity mode, with a sensitivity rate of approximately 70% and a specificity rate of more than 90% in the total group and in the subset of patients with correlative CT data. In the low-sensitivity mode, CT identified only two of seven metastatic sites, whereas the high-sensitivity mode resulted in an unacceptably high rate of false-positive readings (positive predictive value, 29%). PET correctly identified one additional site of metastasis that was not detected by CT. Conclusions The relatively low sensitivity of PET for identifying locoregional lesions precludes its replacement of conventional CT staging. However, the primary advantage of PET imaging is its superior specificity for tumor detection and improved diagnostic value for distant metastatic sites, features that may substantially affect patient management decisions. In conclusion, PET imaging is useful in the initial staging of esophageal cancer and provides additional and complementary information to that obtained by CT imaging.
146 citations
TL;DR: Spinal osteomyelitis and accompanying soft tissue infection can be diagnosed accurately with a single radionuclide procedure: SPECT Ga-67, which can be used as a reliable alternative when MRI cannot be performed and as an adjunct in patients in whom the diagnosis is uncertain.
Abstract: Purpose The objective of this investigation was to compare the accuracies of bone and Ga-67 scintigraphy and magnetic resonance imaging (MRI) for diagnosing spinal osteomyelitis and to determine the optimal radionuclide approach to this disorder. Methods Twenty-two patients, with 24 sites of possible spinal osteomyelitis, who underwent three-phase bone scintigraphy with SPECT, Ga-67 scintigraphy with SPECT, and MRI with and without contrast were included in this retrospective review. Bone scans were interpreted as three-phase studies, delayed planar images alone, delayed planar plus SPECT, and SPECT alone (to identify uptake patterns). Sequential bone/ Ga-67 images were interpreted as planar and as SPECT studies. Planar and SPECT Ga-67 images were also interpreted alone. Precontrast MRI studies were used to identify osteomyelitis, whereas postcontrast images were used to identify soft tissue infection. Results Eleven sites of spinal osteomyelitis were identified. Tracer uptake in two contiguous vertebrae, as noted on SPECT, was the most accurate bone scan criterion for detecting spinal osteomyelitis (71 %). SPECT bone/Ga-67 was significantly more accurate (92%) than both planar bone/Ga-67 (75%) and bone SPECT (P = 0.15 and P = 0.2, respectively). SPECT Ga-67 was as accurate as SPECT bone/Ga-67 and as sensitive as MRI (91 %); the radionuclide study was slightly but not significantly more specific (92% vs. 77%) than MRI. Of 11 sites of extraosseous infection, 10 were identified on MRI, 9 on SPECT Ga-67, 7 on planar Ga-67, and none on bone scintigraphy. Conclusions Spinal osteomyelitis and accompanying soft tissue infection can be diagnosed accurately with a single radionuclide procedure: SPECT Ga-67. This procedure can be used as a reliable alternative when MRI cannot be performed and as an adjunct in patients in whom the diagnosis is uncertain.
138 citations
TL;DR: Acute or chronic infectious mastitis and postsurgical hemorrhagic inflammatory mastitis should be considered in patients who have a breast mass, especially those with a history of tenderness or surgery.
Abstract: Purpose Whole-body fluorine-18 fluorodeoxyglucose (F-18 FDG) positron emission tomography (PET) scanning has been useful in the management of breast cancer. However, F-18 FDG uptake sometimes has been associated with benign breast disease. Four cases are reported of F-18 FDG breast uptake caused by infectious or inflammatory mastitis that mimics malignant disease. Methods and results Two women had F-18 FDG whole-body scans for the evaluation of a large breast mass after inconclusive results of ultrasonography. In both cases, intense focal F-18 FDG breast uptake was noted that mimicked breast cancer. Histologic examination showed, in one patient, chronic granulomatous infiltration that likely represented tuberculous mastitis, because she showed a good clinical response to empirical anti-tuberculous treatment. The second patient had lactational changes associated with acute inflammation, and the culture grew Staphylococcus aureus. The breast mass completely disappeared 3 weeks after a course of antibiotic treatment. The other two patients had staging F-18 FDG PET scans 1 and 12 months after lumpectomy for breast carcinoma to detect residual, recurrent, or metastatic disease. Both scans showed a ring-like uptake in the involved breast, with superimposed intense focal uptake suggesting tumor necrosis centrally and malignant foci peripherally. In both cases, histologic examination revealed hemorrhagic inflammation secondary to postsurgical hematomas and no evidence of malignancy. Conclusion Acute or chronic infectious mastitis and postsurgical hemorrhagic inflammatory mastitis should be considered in patients who have a breast mass, especially those with a history of tenderness or surgery.
114 citations
TL;DR: Peripheral lymphatics can now be easily visualized and follow-up evaluation of patients with lymphedema is possible because lymphangioscintigraphy can be performed before and after medical treatment.
Abstract: PurposeThe primary difficulty in evaluating and treating peripheral lymphedema is visualization of the lymphatics. Functional lymphatic studies have been performed on patients with peripheral edema to diagnose lymphedema, to determine its severity, and to understand the varied drainage patterns.Meth
105 citations
TL;DR: Preliminary data suggest that double-tracer subtraction scintigraphy, combined with neck US, appears to be the preferable preoperative imaging procedure in hyperparathyroidism patients with concomitant thyroid nodular disease.
Abstract: We set up a modified technetium-99m (Tc-99m) pertechnetate/Tc-99m MIBI (Tc-MIBI) subtraction scintigraphy for parathyroid imaging by introducing the use of potassium perchlorate (KCLO4). Initially, the effect of KCLO4 on technetium thyroid wash-out was evaluated in five healthy volunteers: 40-minute dynamic studies of the thyroid were obtained 20 minutes after the injection of technetium 150 MBq (4 mCi), both in baseline conditions and after the oral administration of 400 mg KCLO4. After an average latency time of 10.5 minutes, KCLO4 administration resulted in fast and relevant technetium thyroid wash-out with a mean half-time of 16.2 minutes (the half-time was 142.8 minutes in baseline conditions), and a 40-minute reduction of thyroid activity of 78% (it was 14% in baseline conditions). Based on these findings, a new Tc-MIBI subtraction procedure was established as follows: 1) 150 MBq technetium (4 mCi) injection; 2) 400 mg KCLO4 administered orally; 3) patient neck immobilization; 4) acquisition of a 5-minute technetium thyroid scan; 5) 500 MBq MIBI (13.5 mCi) injection; 6) acquisition of a sequence of seven MIBI images, each lasting 5 minutes; and 7) processing (image realignment when necessary, background subtraction, normalization of MIBI images to the maximum pixel count of the technetium image, and subtraction of the technetium image from the MIBI images). In addition, high-resolution neck ultrasound (US) was performed in all cases on the same day as the scintigraphic evaluation. Eighteen consecutive patients with primary hyperparathyroidism were enrolled in the study. Tc-MIBI scintigraphy revealed a single adenoma in all cases and US showed this finding in 15 of 18 cases (83.3%). Furthermore, in three patients, a thyroid nodule associated with hyperparathyroidism was detected by technetium thyroid scans and neck US. In all patients, the parathyroid adenoma was easily identified on both the 20- to 40-minute MIBI and subtracted (MIBI-Tc) images. Regarding the scintigraphic parameters, no difference was found between parathyroid adenomas located in the region of the thyroid bed or in ectopic sites and in parathyroid adenomas with a retrothyroid location. Surgical findings confirmed the presence of a single parathyroid adenoma in all cases. In the three patients with a concomitant thyroid nodule, thyroid lobectomy was performed. These preliminary data suggest that 1) double-tracer subtraction scintigraphy, combined with neck US, appears to be the preferable preoperative imaging procedure in hyperparathyroidism patients with concomitant thyroid nodular disease, 2) in the Tc-MIBI parathyroid scan, the use of KCLO4 results in a rapid and relevant technetium thyroid clearance, improving the quality of MIBI images and making the visualization of parathyroid adenomas, particularly those located behind the thyroid gland, easier.
64 citations
TL;DR: Results indicate that In-111 labeling of hepatocytes is useful for the short-term noninvasive analysis of the biodistribution of transplanted hepatocytes in a 5-year-old child with omithine transcarbamoylase deficiency.
Abstract: Purpose Hepatocyte transplantation is useful for ex vivo gene therapy and liver repopulation. Methods for hepatic reconstitution were recently developed, but hepatocyte transplantation systems must be optimized. The authors report their experience with In-111 oxyquinolone labeling of a test dose of hepatocytes (108 cells) for noninvasive assessment of the biodistribution of transplanted hepatocytes in a 5-year-old child with omithine transcarbamoylase deficiency. Materials and methods Donor hepatocytes (approximately 108) were radiolabeled using a commercially available In-111 oxyquinolone solution (specific activity of 1 mCi/ml). Results The overall labeling efficiency was 36.4%. A final dose of approximately 290 ,uCi of the In-111-labeled hepatocytes in 10 ml serum-free phosphate-buffered saline was infused percutaneously into the portal vein approximately 2.5 hours after their preparation. The study was performed 3 hours before cell transplantation (109 cells). Quantitative analysis of the biodistribution of In-111-labeled hepatocytes indicated that cells were predominantly localized in the liver immediately after portal vein-infused transplantation. The predominant hepatic distribution was persistent for as long as 7 days after the procedure, with an average liver-to-spleen ratio of 9.5 to 1. No significant pulmonary radiotracer uptake was present. Conclusion These results indicate that In-111 labeling of hepatocytes is useful for the short-term noninvasive analysis of the biodistribution of transplanted hepatocytes.
64 citations
TL;DR: A 58-year-old man had severe lower back pain after minor trauma and was referred for injection of betamethasone and lignocaine into the left iliolumbar angle, which was followed by immediate relief of pain.
Abstract: A 58-year-old man had severe lower back pain after minor trauma. This was initially treated with simple analgesics but with little effect. He was referred for injection of betamethasone and lignocaine into the left iliolumbar angle, which was followed by immediate relief of pain. One week later, he was hospitalized for worsening back pain, fever, and night sweats. Results of plain radiographs of the lumbar spine were reported as normal. Scintigraphy was consistent with a paraspinal abscess, which was confirmed on CT, MRI, and blood cultures. Blood cultures obtained at the time of admission grew Staphylococcus aureus, which was sensitive to methicillin. The patient responded to intravenous antibiotics.
TL;DR: Attenuation artifacts in Tl-201 SPECT occur frequently and are not confined to easily identifiable subgroups of patients, so measures to improve specificity of SPECT (e.g., prone or gated imaging) or alternative imaging techniques such as PET have potential advantages for everyone, not simply for obese patients and women with large breasts.
Abstract: Purpose Myocardial perfusion imaging can be performed using SPECT or positron emission tomography (PET). SPECT has lower specificity than PET, largely as a result of attenuation artifacts; however, it is more widely available. The authors describe a study of the effect of sex and body weight on the incidence of SPECT attenuation artifacts using a retrospective comparison of TI-201 SPECT and Rb PET. Methods One hundred sixty-one persons (101 men, 60 women; 81 normal weight, 80 overweight) underwent TI-201 SPECT and Rb PET. The incidence of observed perfusion defects was studied in territories of the three major coronary arteries. SPECT and PET results were also compared with those of angiography in a subset of 75 patients. Results One hundred fourteen defects were reported on Rb PET compared with 176 defects with TI-201 SPECT. Excess TI-201 SPECT defects occurred in male and female, normal-weight and overweight persons. The average specificity was 64% for TI-201 SPECT and 84% for Rb PET, reflecting this difference. Conclusions Attenuation artifacts in TI-201 SPECT occur frequently and are not confined to easily identifiable subgroups of patients. Therefore, measures to improve specificity of SPECT (e.g., prone or gated imaging) or alternative imaging techniques such as PET have potential advantages for everyone, not simply for obese patients and women with large breasts. In addition, awareness of the prevalence of SPECT attenuation artifacts, in both sexes and all weight categories, may contribute to improved accuracy of interpretation.
TL;DR: FDG PET contributes important information not provided by CT and has a substantial effect on the clinical management of patients with malignant melanoma.
Abstract: Purpose: To assess the effect of positron emission tomography (PET) with fluorine-18 fluorodeoxyglucose (FDG) on the treatment of patients with cutaneous malignant melanoma. Materials and Methods: We retrospectively reviewed the medical records of 38 patients with newly diagnosed (n = 25) and recurrent (n = 13) cutaneous melanoma who were referred for evaluation with FDG PET imaging at our institution. We compared the PET findings with computed tomography (CT), which was available in 21 (55%) patients, and tabulated the changes in the diagnostic evaluation and therapeutic management that were prompted by PET during a follow-up period of 10 to 36 months. Results: Compared with PET, the extent of disease was underestimated by CT in 5 (13%) patients. Planned surgical resection of metastases was canceled in two of these patients. In another patient, surveillance PET detected an unsuspected hypermetabolic abdominal mass that was noted on a subsequent CT to arise from the small bowel. The mass was found to be jejunal metastatic melanoma at the time of resection. Overall, PET influenced surgical management in 3 (8%) patients, but it did not affect the wait-and-watch strategy or decision to initiate immunotherapy in the others. Conclusions: FDG PET contributes important information not provided by CT and has a substantial effect on the clinical management of patients with malignant melanoma.
TL;DR: Positron emission tomography (PET) using fluorine-18-labeled fluorodeoxyglucose (FDG) is an imaging technique with high sensitivity for malignant tumors as mentioned in this paper.
Abstract: PurposePancreatic islet cell tumors are potentially malignant tumors and are often difficult to detect with current imaging modalities. Positron emission tomography (PET) using fluorine-18–labeled fluorodeoxyglucose (FDG) is an imaging technique with high sensitivity for malignant tumors. The aim of
TL;DR: Rhinoscintigraphy proved to be a reliable, easily reproducible, and harmless method, so it may be used for follow-up examinations in patients who have had surgery of the nose and paranasal sinuses, and for drug therapy of rhinopathic conditions.
Abstract: Purpose: This was a radioisotope study of nasal mucociliary clearance of total and subtotal nasal obstruction.
Methods: Rhinoscintigraphy was performed by insufflating 1.85 MBq (69 mCi) Tc- 99m MAA in 20 patients. Six cases were regarded as the control group, because the presence of small spurs does not affect nasal patency. The remaining 14 patients had various rhinopathic conditions. Two regions of interest were selected, one in the nasal cavity and one in the pharynx. Mucociliary transport speed was calculated.
Results: This parameter appeared to be a sensitive index for the assessment of the degree of mucociliary alteration. It showed that polyposis impairs mucociliary transport most severely, thus confirming the results of other published studies.
Conclusions: Rhinoscintigraphy proved to be a reliable, easily reproducible, and harmless method, so it may be used for follow-up examinations in patients who have had surgery of the nose and paranasal sinuses, and for drug therapy of rhinopathic conditions.
TL;DR: Using both the dual-isotope procedure and the subtraction analysis software with the ProstaScint examination provides additional information for staging primary and possibly recurrent prostate cancer compared with standard imaging techniques.
Abstract: Purpose: Whole-body, regional planar, and SPECT imaging using the In-111-labeled monoclonal antibody capromab pendetide (In-111 MAb; ProstaScint) has been shown to increase the detection of early disease spread in patients with prostate cancer. However, recognition of metastatic tumor sites can be difficult, especially if the involved nodes are near blood vessels. We have developed an alternate approach to the identification of metastatic sites that is based on a single simultaneous In-111 MAb and Tc-99m RBC SPECT acquisition of the pelvis and abdomen on day 5 after injection. We have also developed software that dynamically subtracts the Tc-99m RBC data set (vascular component) from the In-111 MAb data set (prostate and lymph node component), which allows for easier identification of metastatic sites. Methods: We evaluated the effectiveness of Prosta Scint for staging 145 patients with prostate cancer, 19 newly diagnosed and 126 with recurrence, using these two modifications. Results: With clinical follow-up in 13 of 19 (68%) patients with primary disease, 10 of 13 (78%) had organconfined disease. With follow-up in 64 of 126 (51%) patients with possible recurrent disease, 49 of 64 (77%) were found to have prostatic fossa activity only. Disease stage was deemed more advanced in 3 of 13 (22%) patients with primary cancer and in 13 of 64 (20%) of those with recurrent disease based on ProstaScint findings when all other imaging tests were inconclusive. Six patients with recurrent disease had negative results of their scans. In the 16 patients with more advanced disease, 3 of 59 lesions (5%) were documented as false positive, and there were no reported cases of false-negative findings. Conclusions: Using both the dual-isotope procedure and the subtraction analysis software with the Prosta Scint examination provides additional information for staging primary and possibly recurrent prostate cancer compared with standard imaging techniques.
TL;DR: The authors describe a patient with infective thyroiditis complicating retropharyngeal abscess caused by a chicken bone that perforated the upper esophagus.
Abstract: Acute suppurative thyroiditis is an uncommon condition. Most patients have preexisting oropharyngeal fistulae. Penetrating oropharyngeal injuries resulting from swallowed foreign bodies provide an acquired channel of infection spreading into the relatively resistant thyroid gland. The authors describe a patient with infective thyroiditis complicating retropharyngeal abscess caused by a chicken bone that perforated the upper esophagus. Transient thyrotoxicosis complicating acute suppurative thyroiditis is very rare. Pertechnetate and Ga-67 scans confirmed extensive inflammation of the thyroid gland and the release of hormones as the cause, as distinct from concurrent Graves' disease. Awareness of this unusual complication is important to avoid inappropriate treatment for hyperthyroid disease.
TL;DR: A 14-year-boy who had a midline neck swelling for 8 to 9 years was described, and a Tc-99m sodium pertechnetate thyroid scan showed dual ectopic thyroid glands in the sublingual and subhyoid regions.
Abstract: Dual ectopic thyroid glands rarely occur, and only six cases have been reported in the literature. The authors describe a 14-year-boy who had a midline neck swelling for 8 to 9 years. The swelling increased gradually, but he had no pressure symptoms. The thyroid hormone profile showed a moderately increased thyroid-stimulating hormone value and normal T3 and T4 levels. A Tc-99m sodium pertechnetate thyroid scan showed dual ectopic thyroid glands in the sublingual and subhyoid regions.
TL;DR: PE is not a rare complication in patients with NS, and is usually clinically silent, except for the association with elevated levels of fibrinogen and antithrombin III.
Abstract: Purpose: Patients with nephrotic syndrome (NS) have an increased tendency to develop thrombosis and even to progress to pulmonary embolism (PE). This study was performed to determine the incidence of PE in NS with severe hypoalbuminemia and to investigate the possible role of ventilation-perfusion (V/Q) lung scans to evaluate these patients. Methods: Eighty-nine patients with NS (serum albumin concentration < 2 g/dl) and risk factors for PE were studied. In all patients, the probability that PE would develop was assessed based on the results of V/Q lung scans (Xe-133 for ventilation and Tc-99m MAA for perfusion imaging). The lung scans were judged using the modified Prospective Investigation of Pulmonary Embolism Diagnosis criteria. In 25 (28%) patients whose lung scans showed an intermediate or low probability, but for whom there was a strong clinical indication of PE, pulmonary angiography was performed. The patients' clinical symptoms and signs on initial examination were observed. Additional examinations included electrocardiograms, chest radiography, and hematochemical tests such as albumin, blood urea nitrogen, creatinine, cholesterol, triglycerides, fibrinogen, antithrombin III, prothrombin time, and activated partial thromboplastin time. Results: Based on the findings of lung scans, 19 (21%) of the patients were categorized as having a high probability of PE. However, pulmonary angiography found that 10 (11%) other patients had PE despite having lung scan findings categorized as intermediate or low probability of PE. Except for plasma fibrinogen and antithrombin III levels, neither the clinical symptoms and signs, electrocardiogram findings, chest radiograph results, nor values of hematochemical testing were consistent with the occurrence of PE in these 29 patients. Conclusion: The results of this study suggest that PE is not a rare complication in patients with NS, and is usually clinically silent. In this series, the occurrence of PE did not appear to be always correlated with the clinical or hematochemical severity of NS, except for the association with elevated levels of fibrinogen and antithrombin III. When treating the clinical symptoms of patients with NS, physicians should be alert to the possible complication of PE. Serial V/Q lung scans may provide valuable clues in the evaluation of these patients.
TL;DR: The suggested technique is generally free of the controversies noted above and applies to most patients and includes various maneuvers that aim to improve the rate of sentinel node visualization using the gamma camera and the accuracy of node detection.
Abstract: Sentinel node detection is an important part of the clinical management of newly diagnosed melanoma. Now there is a similar or even greater enthusiasm for sentinel node evaluation in patients with breast carcinoma. However, controversies exist regarding the dose, volume, and route of administration. Even the role of lymphoscintigraphy itself, in contrast to using only a hand-held gamma probe during surgery for sentinel node detection, is being debated. Nevertheless, many centers and surgeons find that lymphoscintigraphy images are valuable in the treatment of patients and they use lymphoscintigraphy as a guide during surgery and to confirm the results obtained with the hand-held probe. Centers just beginning to use lymphoscintigraphy may find the images especially useful. Given this fact, the authors wanted to define the practical and technical aspects of performing lymphoscintigraphy in patients with breast cancer and examined various methods for the optimization of the technique of image acquisition. The suggested technique is generally free of the controversies noted above and applies to most patients. It includes various maneuvers that aim to improve the rate of sentinel node visualization using the gamma camera and the accuracy of node detection. The recommendations presented here should prove useful for both those experienced and for those centers just beginning to use the technique of lymphoscintigraphy.
TL;DR: Brain death assessment by Tc-99m HMPAO scintigraphy has proved to be a reliable, safe, and cost-effective bedside method and may have practical application in the assessment of brain death in potential cadaveric donors.
Abstract: Purpose Diagnosing brain death is important in managing the comatose patient for whom the continuation of life support is being questioned and when organ harvesting is being considered. The virtual immediate localization of Tc-99m HMPAO to cerebral and cerebellar tissue provides an index of blood perfusion, and its absence denotes brain death. Other methods for assessing brain death include cerebral angiography, MRI, CT imaging after inhalation of stable xenon, electroencephalography, and clinical examination. The contrast material used for angiography may damage harvested organs, and the other studies have significant errors. MRI, CT imaging, and angiography are unsuitable for bedside use. Methods Twenty-three patients, who presented with head trauma, prolonged anoxia or intrinsic brain disease (e.g., glioblastoma multiforme) and who were brain-dead by clinical examination criteria, were referred to the nuclear medicine division for verification of brain death. For adults, approximately 25 mCi Tc-99m hexamethylpropylene amineoxime (HMPAO) was administered intravenously. All patients but one were imaged using a mobile scintillation camera at the bedside. Results We demonstrated (1) both cerebral and cerebellar perfusion, (2) neither cerebral nor cerebellar perfusion, (3) cerebral without cerebellar perfusion, and (4) cerebellar without cerebral perfusion. Patients without cerebral perfusion were diagnosed as brain-dead. The significance of a viable cerebellum in the absence of cerebral viability was not fully appreciated, although organs were harvested from such patients. We determined how well the clinical examination criteria held up in the diagnosis of brain death against the new gold standard of Tc-99m HMPAO scintigraphy: Clinical examination criteria correctly predicted brain death only 83% of the time compared with HMPAO scintigraphy. Conclusions Brain death assessment by Tc-99m HM-PAO scintigraphy has proved to be a reliable, safe, and cost-effective bedside method and may have practical application in the assessment of brain death in potential cadaveric donors.
TL;DR: A 53-year-old man was found serendipitously to have increased blood-pool uptake in the right lobe of the thyroid during a radionuclide ventriculography study for left ventricular function.
Abstract: A 53-year-old man was found serendipitously to have increased blood-pool uptake in the right lobe of the thyroid during a radionuclide ventriculography study for left ventricular function. Primary thyroid hemangioma is a rare condition, with only two cases reported in the literature. Secondary hemangioma may occur as a result of fine-needle aspiration. This technique may cause hematoma formation, which generally resolves normally, but on rare occasions it can lead to cavernous hemangioma formation. In patients with a thyroid swelling who have a cold nodule on a thyroid scan and only blood on repeated fine-needle aspiration, Tc-99m erythrocyte blood-pool imaging may be performed to diagnose hemangioma.
TL;DR: The Tc-99m HMPAO leukocyte scan is useful in the diagnosis of bone infection, regardless of the presence of orthopedic implants, and the additional SPECT images may be helpful to localize the site of infection more accurately.
Abstract: Purpose: In this study, the diagnostic value of Tc-99m hexamethylpropylene amine oxime (HMPAO) leukocyte scans and the role of additional SPECT in the diagnosis of bone infection were evaluated. Materials and Methods: The Tc-99m HMPAO leukocyte scans of 37 patients with clinically suspected bone infection were reviewed. The patients were divided into two groups according to the presence of orthopedic implants. Early (4 to 6 hours) and delayed (18 to 20 hours) planar images and early SPECT images were obtained. The final diagnosis of infection was made based on the pathologic, bacteriologic, and surgical data and clinical follow-up. Results: Group 1 (25 patients with orthopedic implants) included 15 true-positive, 1 false-negative, 7 true-negative, and 2 false-positive results. Group 2 (12 patients without orthopedic implants) included 7 true-positive, 1 false-negative, and 4 true-negative results. The overall sensitivity of the Tc-99m HMPAO leukocyte scan with SPECT to detect bone infection was 92%, with a specificity rate of 85%. (Group 1: sensitivity, 94%; specificity, 78%. Group 2: 88% and 100% sensitivity and specificity, respectively.) Conclusion: The Tc-99m HMPAO leukocyte scan is useful in the diagnosis of bone infection, regardless of the presence of orthopedic implants. The additional SPECT images may be helpful to localize the site of infection more accurately.
TL;DR: A 36-year-old woman who underwent resection of a malignant left adrenal pheochromocytoma who was thought to have metastases in the liver and para-aortic lymph nodes is described.
Abstract: Pheochromocytoma is a chromaffin tumor in which 10% are extra-adrenal and 10% are malignant. I-131 metaiodobenzylguanidine (MIBG) scintigraphy has an important role in the identification of these tumors and investigation of metastatic lesions. The authors describe a 36-year-old woman who underwent resection of a malignant left adrenal pheochromocytoma who was thought to have metastases in the liver and para-aortic lymph nodes. Fusion images of I-131 MIBG SPECT and magnetic resonance studies were obtained to properly identify the metastatic lesions. These fusion images helped greatly in subsequent surgery.
TL;DR: FDG positron emission tomography has been used extensively in the diagnosis of malignant conditions with high rates of sensitivity and specificity, however, increased FDG uptake is not limited to malignant tissue.
Abstract: Fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography has been used extensively in the diagnosis of malignant conditions with high rates of sensitivity and specificity. However, increased FDG uptake is not limited to malignant tissue. In general, lesions with a mild degree of FDG uptake as measured by standardized uptake values less than 2.0 are considered benign, whereas those with values greater than 2.5 are usually regarded as malignant. Standardized uptake values in the kidney can be as high as 22 as a result of excretion of FDG through urine. Two cases are reported in which renal abnormalities could not be distinguished from urine based on standard uptake values alone.
TL;DR: Most patients with endogenous subclinical thyrotoxicosis have underlying thyroid abnormalities that can be determined by nuclear imaging and, in selected cases, thyroid antibody studies.
Abstract: Purpose:Endogenous subclinical thyrotoxicosis is diagnosed when a patient who is not taking exogenous thyroid hormone has a suppressed level of thyroid-stimulating hormone with normal levels of the free thyroid hormones thyroxine and triiodothyronine and other known causes of a suppressed thyroid-st
TL;DR: This case shows both the efficacy and the safety of Sm-153 lexidronam in repeated treatments for metastatic bone pain in patients with prostate cancer.
Abstract: A patient with stage D3 prostate cancer was given 11 separate doses of samarium-153 lexidronam (Sm-153 ethylenediaminetetramethylene phosphonate) of 1 mCi/kg (37 MBq/kg) in a period of 28 months for bone pain from metastases. With the first five doses, Sm-153 lexidronam clearly reduced his bone pain and improved his quality of life, as determined by pain-assessment scores and the patient's self-assessment of its effect on his ability to perform activities of daily living. With doses 6 through 11, pain at baseline was on average less, and as a result beneficial effects after treatment were not as apparent. Samarium-153 lexidronam produced transient decreases in the leukocyte and platelet counts, but these never became low enough to cause clinical concern. This case shows both the efficacy and the safety of Sm-153 lexidronam in repeated treatments for metastatic bone pain in patients with prostate cancer.
TL;DR: The importance of bone scintigraphy as an imaging method in patients with an unclear diagnosis of Erdheim-Chester disease is discussed, as is its role for the detection of sites of skeletal involvement in other diseases.
Abstract: Erdheim-Chester disease (ECD) is a rare disorder that has been reported fewer than 60 times in the literature. Although clinical findings seem to be specific at first sight, histologic classification remains unclear. It has not been decided whether ECD is part of the spectrum of histiocytoses or whether it may be a lipid storage disorder or even a primary macrophage cell disorder, although it does show a distinct histologic pattern. However, the clinical appearance alone shows several typical features, rendering the diagnosis very probable if present. This article illustrates the importance of bone scanning in ECD, because the scintigraphic pattern of involved skeletal sites may in themselves lead to the diagnosis. Several differential diagnoses are considered. The importance of bone scintigraphy as an imaging method in patients with an unclear diagnosis is discussed, as exemplary in ECD, as is its role for the detection of sites of skeletal involvement in other diseases.