This retrospective study was carried out to determine the typical patterns of (18)F-FDG uptake in uncomplicated total hip arthroplasty (THA).(18)F-FDG-PET images of 62 asymptomatic THA patients who had undergone whole body scanning were evaluated for this retrospective study. The uptake was assessed qualitatively as positive or negative in the head/neck and the stem of the prosthesis. There were 76 hip prosthesis scans (34 left side and 42 right) and the average time following surgery was 75 months (range from 40 days to 372 months). Furthermore, the time course after surgery was subdivided into 3 time interval groups: Group I less than 2 years, Group II between 2 to 5 years, Group III more than 5 years. The regions of assessment were: head region including acetabulum and femoral head, femoral neck, trochanter, and femoral shaft.In patients who demonstrated increased peri-prosthetic (18)F-FDG uptake (59 of the 76 hip scans), the activity was confined to the femoral neck and proximal femoral shaft with the majority in the neck regions alone: 68% (40 of 59). Majority of the uptake was noted in the femoral neck, proximal shaft and trochanteric regions.Uptake of (18)F-FDG in the asymptomatic patients with THA is commonly visualized and appears to be confined to the proximal segment of the prosthesis with minimal or no activity in its femoral segment.
Esophageal cancer frequently causes a focal intense FDG uptake on positron emission tomography (PET) imaging while esophagitis often results in a mild to moderate degree of FDG activity in a diffuse pattern. However, detection of an esophageal cancer can become difficult in the presence of a diffuse esophageal activity because of esophagitis. We present such case in which esophageal cancer superimposed by Candidal esophagitis is difficult to recognize on FDG PET images.
The authors describe a 42-year-old man with insular thyroid carcinoma. In this patient, iodine-131 (I-131) and technetium-99m (Tc-99m) tetrofosmin imaging were performed to investigate residual thyroid tissue and metastatic foci of tumor. Both I-131 and Tc-99m tetrofosmin images showed metastatic foci, but Tc-99m tetrofosmin imaging revealed the lesions better than did the I-131 scan. Tc-99m tetrofosmin imaging does not require withholding of thyroid hormone suppression and can be used for follow-up evaluation of patients with insular thyroid carcinoma.
In cervical cancer (CC), fluorine18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) has been proven to be beneficial for patient management. Positron emission tomography/CT is useful in pretreatment evaluation due to the ability to evaluate disease extent and to assess regional lymph nodes as well as distant sites for metastases. Positron emission tomography/CT has an impact on treatment planning as well as it is incorporated in radiation therapy planning, resulting in more appropriate and effective treatment with less cost and radiation dose to normal tissues. Positron emission tomography/CT is used to predict early treatment response and to assess treatment response after completion of concurrent chemoradiation therapy. Positron emission tomography/CT has been used for surveillance after treatment as well as for restaging in suspected recurrent or metastatic disease. Qualitative PET/CT imaging findings as well as quantitative parameters such as maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) are useful to predict prognosis and clinical outcome. Moreover, PET imaging using other radiotracers to detect and quantify hypoxia may help to identify aggressive tumors and predict treatment outcome even though it is not widely clinical used. Positron emission tomography/magnetic resonance imaging (PET/MRI) instruments are now available, which may potentially improve evaluation of primary tumors and metastatic sites given the improved soft tissue contrast resolution of MRI relative to CT. This article reviews the role of 18F-FDG PET/CT, hypoxia agent PET/CT, and 18F-FDG PET/MRI in the management of patients with CC.
Purpose: The purpose of this study was to determine if an FDG-PET study was able to visualize muscle uptake of the chest and abdomen in patients with chronic obstructive pulmonary disease (COPD). Methods: This study included 25 patients with COPD and 25 patients without COPD who had undergone a FDG-PET study. The nonattenuation-corrected images were used to determine the degree of FDG uptake in the intercostals, subscapular, abdominal rectus, and abdominal oblique muscles. The intensity of uptake in the muscles was rated on a 4-point grading scale with 1 being less, 2 the same, 3 slightly more, and 4 markedly more intense than the sternum. Results: Thirteen patients with COPD demonstrated FDG activity in the intercostal muscles that was equal to or greater than the sternum and the tracer was demonstrated predominantly in the inferolateral chest wall (n = 8), the entire lateral chest wall (n = 2), the posteroinferior chest wall (n = 2), and the entire chest wall (n = 1). In all 13 patients with COPD who demonstrated FDG activity in the abdominal oblique muscles, the site of muscle activity was predominantly in the anteroinferior abdominal wall (n = 8), the lateral wall (n = 4), and the anterior wall (n = 1). In patients without known COPD, the frequency and intensity of uptake in the muscles were less than those with the disease. Conclusion: This study demonstrates the ability of FDG-PET imaging to assess muscle function in respiratory disorders and may prove to be of some value in further characterizing this disorder.
The optimal management of patients with melanoma requires accurate imaging techniques that can screen the entire body for metastases. One of the most used tests for this purpose is bone scintigraphy. PET has been reported to be more sensitive than bone scintigraphy in some malignancies. In our case, FDG-PET was also superior to bone scintigraphy in detecting the extent of skeletal disease in a patient with melanoma. This is likely the result of the fact that metastasis to bone marrow may not result in bone reaction in certain conditions and therefore bone scans may remain negative despite skeletal involvement.
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