BACKGROUND Incidentally found thyroid tumor(thyroid incidentaloma,TI)on F-18 fluorodeoxyglucose(FDG)positron emission tomography-computed tomography(PETCT)is reported in 2.5%-5%of patients being investigated for non-t...BACKGROUND Incidentally found thyroid tumor(thyroid incidentaloma,TI)on F-18 fluorodeoxyglucose(FDG)positron emission tomography-computed tomography(PETCT)is reported in 2.5%-5%of patients being investigated for non-thyroid purposes.Up to 50%of these cases have been diagnosed to be malignant by cytological/histological results.Ultrasonography(US)and fine-needle aspiration cytology are recommended for thyroid nodules with high FDG uptake(hypermetabolism)that are 1 cm or greater in size.It is important to accurately determine whether a suspicious hypermetabolic TI is malignant or benign.AIM To distinguish malignant hypermetabolic TIs from benign disease by analyzing F-18 FDG PET-CT parameters and to identify a cut-off value.METHODS Totally,12761 images of patients who underwent F-18 FDG PET-CT for nonthyroid purposes at our hospital between January 2016 and December 2020 were retrospectively reviewed,and 339 patients[185 men(mean age:68±11.2)and 154 women(mean age:63±15.0)]were found to have abnormal,either focal or diffuse,thyroid FDG uptake.After a thorough review of their medical records,US,and cytological/histological reports,46 eligible patients with focal hypermetabolic TI were included in this study.The TIs were categorized as malignant and benign according to the cytological/histological reports,and four PET parameters[standardized uptake value(SUV)max,SUV_(peak),SUV_(mean),and metabolic tumor volume(MTV)]were measured on FDG PET-CT.Total lesion glycolysis(TLG)was calculated by multiplying the SUV_(mean) by MTV.Both parametric and non-parametric methods were used to compare the five parameters between malignant and benign lesions.Receiver operating characteristic(ROC)curve analysis was performed to identify a cut-off value.RESULTS Each of the 46 patients[12 men(26.1%;mean age:62±13.1 years)and 34 women(73.9%;mean age:60±12.0 years)]with focal hypermetabolic TIs had one focal hypermetabolic TI.Among them,26(56.5%)were malignant and 20(43.5%)were benign.SUV_(max),SUV_(peak),SUV_(mean),and TLG were all higher in malignant lesions than benign ones,but the difference was statistically significant(P=0.012)only for SUV_(max).There was a positive linear correlation(r=0.339)between SUV_(max) and the diagnosis of malignancy.ROC curve analysis for SUV_(max) revealed an area under the curve of 0.702(P<0.05,95%confidence interval:0.550-0.855)and SUV_(max) cut-off of 8.5 with a sensitivity of 0.615 and a specificity of 0.789.CONCLUSION More than half of focal hypermetabolic TIs on F-18 FDG PET-CT were revealed as malignant lesions,and SUV_(max) was the best parameter for discriminating between malignant and benign disease.Unexpected focal hypermetabolic TIs with the SUV_(max) above the cut-off value of 8.5 may have a greater than 70%chance of malignancy;therefore,further active assessment is required.展开更多
Here we report the case of a 60-year-old patient previously affected by prostate cancer treated with prostatectomy. After surgery, the patient was scheduled for routine follow up examinations including biochemical and...Here we report the case of a 60-year-old patient previously affected by prostate cancer treated with prostatectomy. After surgery, the patient was scheduled for routine follow up examinations including biochemical and imaging evaluations. PSA testing evidenced a light, continuous increase in the course of the last four sampling. This finding calls for a biochemical recurrence. Thus the patient underwent a 18F-Fluorocholine (FCH) PET/CT to detect the possible sites of the relapse. FCH PET/CT did not disclose any focal uptake suggesting a metastatic spread. However, one focal uptake was noticed in the lower pole of the right thyroid lobe, corresponding to a hypodense nodule. Therefore, the patient was studied with 99 mTc thyroid scan and neck ultrasound. Both examinations had findings suspicious of a neoplasm. The fine needle aspiration biopsy (FNAB) that was carried out to rule out a malignancy, gave a TIR2 result. FCH PET/CT may give thyroidal uptakes in benign lesions.展开更多
Incidental lesions of the thyroid are increasingly discovered as the prevalence of medical imaging escalates.The likelihood of malignancy must be assessed for each of these incidentalomas.The utility of the metabolic ...Incidental lesions of the thyroid are increasingly discovered as the prevalence of medical imaging escalates.The likelihood of malignancy must be assessed for each of these incidentalomas.The utility of the metabolic data derived from the identification of these lesions on PET/CT imaging is unclear.The overall rate of detection of thyroid incidentalomas on PET/CT is estimated at 1.5%-4.2%.However,this rate varies by the pattern of uptake.Several studies have evaluated predictive measures such as maximal standardized uptake value(SUVmax)and radiomics.However,no definitive conclusion has been reached.Given that the majority of PET/CT scans are performed in the context of malignancy,we recommend first assessing the general condition and life expectancy of patients when PET-detected thyroid incidentalomas are unveiled.We also recommend considering observation versus diagnostic workup with further imaging and/or fine-needle aspiration and cytology.展开更多
文摘BACKGROUND Incidentally found thyroid tumor(thyroid incidentaloma,TI)on F-18 fluorodeoxyglucose(FDG)positron emission tomography-computed tomography(PETCT)is reported in 2.5%-5%of patients being investigated for non-thyroid purposes.Up to 50%of these cases have been diagnosed to be malignant by cytological/histological results.Ultrasonography(US)and fine-needle aspiration cytology are recommended for thyroid nodules with high FDG uptake(hypermetabolism)that are 1 cm or greater in size.It is important to accurately determine whether a suspicious hypermetabolic TI is malignant or benign.AIM To distinguish malignant hypermetabolic TIs from benign disease by analyzing F-18 FDG PET-CT parameters and to identify a cut-off value.METHODS Totally,12761 images of patients who underwent F-18 FDG PET-CT for nonthyroid purposes at our hospital between January 2016 and December 2020 were retrospectively reviewed,and 339 patients[185 men(mean age:68±11.2)and 154 women(mean age:63±15.0)]were found to have abnormal,either focal or diffuse,thyroid FDG uptake.After a thorough review of their medical records,US,and cytological/histological reports,46 eligible patients with focal hypermetabolic TI were included in this study.The TIs were categorized as malignant and benign according to the cytological/histological reports,and four PET parameters[standardized uptake value(SUV)max,SUV_(peak),SUV_(mean),and metabolic tumor volume(MTV)]were measured on FDG PET-CT.Total lesion glycolysis(TLG)was calculated by multiplying the SUV_(mean) by MTV.Both parametric and non-parametric methods were used to compare the five parameters between malignant and benign lesions.Receiver operating characteristic(ROC)curve analysis was performed to identify a cut-off value.RESULTS Each of the 46 patients[12 men(26.1%;mean age:62±13.1 years)and 34 women(73.9%;mean age:60±12.0 years)]with focal hypermetabolic TIs had one focal hypermetabolic TI.Among them,26(56.5%)were malignant and 20(43.5%)were benign.SUV_(max),SUV_(peak),SUV_(mean),and TLG were all higher in malignant lesions than benign ones,but the difference was statistically significant(P=0.012)only for SUV_(max).There was a positive linear correlation(r=0.339)between SUV_(max) and the diagnosis of malignancy.ROC curve analysis for SUV_(max) revealed an area under the curve of 0.702(P<0.05,95%confidence interval:0.550-0.855)and SUV_(max) cut-off of 8.5 with a sensitivity of 0.615 and a specificity of 0.789.CONCLUSION More than half of focal hypermetabolic TIs on F-18 FDG PET-CT were revealed as malignant lesions,and SUV_(max) was the best parameter for discriminating between malignant and benign disease.Unexpected focal hypermetabolic TIs with the SUV_(max) above the cut-off value of 8.5 may have a greater than 70%chance of malignancy;therefore,further active assessment is required.
文摘Here we report the case of a 60-year-old patient previously affected by prostate cancer treated with prostatectomy. After surgery, the patient was scheduled for routine follow up examinations including biochemical and imaging evaluations. PSA testing evidenced a light, continuous increase in the course of the last four sampling. This finding calls for a biochemical recurrence. Thus the patient underwent a 18F-Fluorocholine (FCH) PET/CT to detect the possible sites of the relapse. FCH PET/CT did not disclose any focal uptake suggesting a metastatic spread. However, one focal uptake was noticed in the lower pole of the right thyroid lobe, corresponding to a hypodense nodule. Therefore, the patient was studied with 99 mTc thyroid scan and neck ultrasound. Both examinations had findings suspicious of a neoplasm. The fine needle aspiration biopsy (FNAB) that was carried out to rule out a malignancy, gave a TIR2 result. FCH PET/CT may give thyroidal uptakes in benign lesions.
文摘Incidental lesions of the thyroid are increasingly discovered as the prevalence of medical imaging escalates.The likelihood of malignancy must be assessed for each of these incidentalomas.The utility of the metabolic data derived from the identification of these lesions on PET/CT imaging is unclear.The overall rate of detection of thyroid incidentalomas on PET/CT is estimated at 1.5%-4.2%.However,this rate varies by the pattern of uptake.Several studies have evaluated predictive measures such as maximal standardized uptake value(SUVmax)and radiomics.However,no definitive conclusion has been reached.Given that the majority of PET/CT scans are performed in the context of malignancy,we recommend first assessing the general condition and life expectancy of patients when PET-detected thyroid incidentalomas are unveiled.We also recommend considering observation versus diagnostic workup with further imaging and/or fine-needle aspiration and cytology.
