We present an interesting case of incidental diffuse fluorodeoxyglucose (FDG) uptake at PET in her left breast, related to atypical breastfeeding practice. Clinically, differential diagnoses of diffuse intense FDG uptake in unilateral breast include advanced breast cancer, breast lymphoma and inflammatory condition. However, normal physiologic lactation may also show increased FDG uptake in the breasts. Therefore, if we encounter that finding in daily practice, we should question the patient regarding unilateral breastfeeding. In addition, mammography and ultrasound would be helpful to confirm the diagnosis.
Adult ; Breast/*metabolism/radionuclide imaging ; Breast Feeding/*methods ; Breast Neoplasms/radionuclide imaging ; Diagnosis, Differential ; Female ; Fluorodeoxyglucose F18/diagnostic use/*pharmacokinetics ; Humans ; Lactation/metabolism ; Lymphoma/radionuclide imaging ; Mammography ; Positron-Emission Tomography ; Radiopharmaceuticals/diagnostic use/*pharmacokinetics ; Ultrasonography, Mammary

OBJECTIVE: Suspicious incidental gastrointestinal FDG uptake during positron-emission tomography/computed tomography (PET/CT) examinations can be caused by different diseases, including malignancies. However, differentiation with PET alone is difficult. The aim of this study was to investigate the potential of PET alone, contrast-enhanced CT (ceCT), and low-dose CT (ldCT) in routine PET/CT protocols for differentiation of incidental gastrointestinal lesions. MATERIALS AND METHODS: Sixty patients with incidental gastrointestinal lesions who underwent a routine PET/CT protocol with ldCT and ceCT were retrospectively analysed. The PET lesions were evaluated regarding their FDG uptake patterns and the standard uptake value. The anatomical correlates in both CT protocols were compared in regard to the correct lesion classification with the reference standard endoscopy. RESULTS: Sixty-two lesions were found in 60 patients (17 malignant, 10 premalignant, 5 benign, 13 inflammatory, 17 physiological). The differentiation of the FDG uptake patterns did not enable reliable lesion classification. The positive predictive value for pathology was 0.81 for ceCT in PET/CT and 0.70 for ldCT. Malignancies were detected in 100% of the patients by ceCT vs. 29.4% by ldCT. The false negative rate of ceCT for all pathologies was 31.1%, vs. 68.9% for ldCT. False positive results (17/62) could not be excluded sufficiently by either CT protocol. CONCLUSION: PET/ceCT protocols provide additional benefit especially in detecting gastrointestinal malignancies as a cause of suspicious incidental gastrointestinal FDG uptake. However, since follow-up endoscopy cannot be forgone due to the considerable false negative rate even with ceCT, the addition of ceCT to a routine PET/ldCT protocol cannot be recommended for this purpose.
Adult ; Aged ; Aged, 80 and over ; Contrast Media/diagnostic use/pharmacokinetics ; Female ; Fluorodeoxyglucose F18/*diagnostic use/pharmacokinetics ; Follow-Up Studies ; Gastrointestinal Diseases/*diagnosis/metabolism ; Gastrointestinal Tract/*metabolism/radiography/radionuclide imaging ; Humans ; Male ; Middle Aged ; Positron-Emission Tomography/*methods ; Reproducibility of Results ; Retrospective Studies ; Tomography, X-Ray Computed/*methods

The radiologic appearance of multiple discrete pulmonary nodules in immunocompetent patients, with cryptococcal infection, has been rarely described. We describe a case of pulmonary cryptococcosis, presenting with bilaterally and randomly distributed nodules on a computed tomography, mimicking hematogeneous metastases. Positron emission tomography does not demonstrate 18F-fluorodeoxyglucose (FDG) uptake, suggesting a low probability for malignancy, which is a crucial piece of information for clinicians when making a management decision. We find the absence of FDG uptake correlates with the pathologic finding of an infectious nodule, composed of fibrosis and necrosis.
Cryptococcosis/metabolism/*radionuclide imaging ; Fluorodeoxyglucose F18/*diagnostic use/pharmacokinetics ; Humans ; Immunocompetence ; Lung Diseases, Fungal/metabolism/*radionuclide imaging ; Lung Neoplasms/radionuclide imaging ; Male ; Middle Aged ; Multimodal Imaging/*methods ; Multiple Pulmonary Nodules/radionuclide imaging ; Positron-Emission Tomography/*methods ; Radiopharmaceuticals/*diagnostic use/pharmacokinetics ; Tomography, X-Ray Computed/*methods

OBJECTIVE: We investigated the clinical significance of incidental diffuse thyroid uptake (DTU) on 18F-FDG PET in subjects without a history of cancer. MATERIALS AND METHODS: This study included 2062 studies from adults who underwent 18F-FDG PET as a cancer screening program. Subjects were divided into the following two groups: with (group I) or without (group II) DTU. The presence of DTU and the thyroid visual grading score were compared with thyroid function tests, serum anti-microsomal antibody (AMA) levels, and the presence of diffuse parenchymal change (DPC) on ultrasonography (USG). RESULTS: DTU was found in 6.6% of the scans (137/2062). Serum thyroid stimulating hormone (TSH) and AMA levels were significantly higher in group I than in group II. Increased AMA level (55.1%) and DPC (48.7%) were more frequently found in group I (p < 0.001). The proportion of subjects with any abnormal results in serum free thyroxine, triiodothyronine, TSH, or AMA levels or DPC on USG was significantly higher in group I than in group II (71.5% vs. 10.6%, p < 0.001), and was significantly and gradually increased according to the visual grading score group (0 vs. 1-2 vs. 3-4 = 10.6% vs. 58.5% vs. 90.9%, p < 0.001). TSH and is AMA levels were significantly increased according to the visual grading score. CONCLUSION: The presence or degree of incidental DTU on 18F-FDG PET is closely correlated with increased serum AMA and TSH levels, and the presence of DPC on USG. Therefore, the most plausible pathological cause of DTU may be cell damage by an autoimmune mechanism.
Adult ; Aged ; Aged, 80 and over ; Antibodies/blood ; Female ; Fluorodeoxyglucose F18/*diagnostic use/pharmacokinetics ; Humans ; *Incidental Findings ; Male ; Microsomes/immunology ; Middle Aged ; Neoplasms ; Positron-Emission Tomography/methods ; Radiopharmaceuticals/*diagnostic use/pharmacokinetics ; Retrospective Studies ; Thyroid Gland/metabolism/*radionuclide imaging/ultrasonography ; Thyrotropin/blood ; Young Adult

F-18-fluorodeoxyglucose (FDG) positron emission tomography/CT is an important whole-body imaging tool in the oncology and widely utilized to stage and restage various malignancies. The findings of significant focal accumulation of FDG in the lung parenchyma in the absence of corresponding CT abnormalities are related to the lung microembolism and known as hot-clot artifacts. Herein we present two cases with focal FDG uptake in the lung parenchyma with no structural lesions on the CT scan and discuss the possible mechanisms.
*Artifacts ; False Positive Reactions ; Female ; Fluorodeoxyglucose F18/*administration & dosage/diagnostic use/pharmacokinetics ; Humans ; Lung/metabolism/radiography/*radionuclide imaging ; Male ; Middle Aged ; Multimodal Imaging/methods ; Positron-Emission Tomography/*methods ; Pulmonary Embolism/radiography/*radionuclide imaging ; Radiopharmaceuticals/*administration & dosage/diagnostic use/pharmacokinetics ; Tomography, X-Ray Computed/methods ; Young Adult

OBJECTIVETo evaluate the value of (18)F-FDG PET-CT for assessment of therapeutic response and prediction of patient outcome after concurrent chemoradiotherapy (CCRT) of non-small cell lung cancer (NSCLC).

METHODSForty six patients with histologically proven stage III NSCLC had two repeated (18)F-FDG PET-CT scans either one week before therapy and at the dose of 40 ∼ 50 Gy. The SUV(max) and changes of the two groups were compared with (1) the therapeutic response and (2) treatment results and long-term survival.

RESULTSOf the 46 eligible cases, the pretreatment SUV(max) of the responding and non-responding groups was 7.59 ± 3.14 and 14.72 ± 4.67, respectively. The midtreatment SUV(max) of the two groups was 2.89 ± 1.39 and 9.82 ± 3.31, respectively. Significant difference(t = 4.74, P = 0.001;t = 7.23, P = 0.001) in SUV(max) was observed both before and during treatment. Furthermore, the percentage change of pretreatment and midtreatment SUV(max) was ΔSUV(max) = 61.9% ± 8.7% and ΔSUV(max) = 33.6% ± 9.0%, also with a significant difference between the two groups (t = 2.83, P = 0.007). In addition, the 1-year survival rate of the the responding and non-responding groups was 68.0% and 38.1%, respectively. The 2-year survival rate of the two groups was 64.0% and 33.3%, respectively, with a significant difference between the two groups (P = 0.043, P = 0.038).

CONCLUSION(18)F-FDG PET-CT is highly effective in detecting therapeutic response in stage III NSCLC patients. The analysis of percentage change of SUV(max) provides incremental value in early prediction of therapeutic response and patient outcome.

Aged ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Carcinoma, Non-Small-Cell Lung ; diagnostic imaging ; metabolism ; pathology ; therapy ; Cisplatin ; administration & dosage ; Combined Modality Therapy ; Female ; Fluorodeoxyglucose F18 ; pharmacokinetics ; Humans ; Lung Neoplasms ; diagnostic imaging ; metabolism ; pathology ; therapy ; Male ; Middle Aged ; Neoplasm Staging ; Paclitaxel ; administration & dosage ; Positron-Emission Tomography ; Prognosis ; Radiopharmaceuticals ; pharmacokinetics ; Radiotherapy, Conformal ; Tomography, X-Ray Computed ; Vinblastine ; administration & dosage ; analogs & derivatives