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Lung cancer, the most frequently diagnosed cancer worldwide, is the leading cause of cancer-associated deaths. In recent years, significant progress has been achieved in basic and clinical research concerning the epidermal growth factor receptor (EGFR), and the treatment of lung adenocarcinoma has also entered a new era of individualized, targeted therapies. However, the detection of lung adenocarcinoma is usually invasive. 18F-FDG PET/CT can be used as a noninvasive molecular imaging approach, and radiomics can acquire high-throughput data from standard images. These methods play an increasingly prominent role in diagnosing and treating cancers. Herein, we reviewed the progress in applying 18F-FDG PET/CT and radiomics in lung adenocarcinoma clinical research and how these data are analyzed via traditional statistics, machine learning, and deep learning to predict EGFR mutation status, all of which achieved satisfactory results. Traditional statistics extract features effectively, machine learning achieves higher accuracy with complex algorithms, and deep learning obtains significant results through end-to-end methods. Future research should combine these methods to achieve more accurate predictions, providing reliable evidence for the precision treatment of lung adenocarcinoma. At the same time, facing challenges such as data insufficiency and high algorithm complexity, future researchers must continuously explore and optimize to better apply to clinical practice. [ABSTRACT FROM AUTHOR]

A 63-year-old male presented with left scrotal swelling and the ultrasound showed a large heterogeneous mass consistent with a testicular malignancy. The patient underwent left-sided orchiectomy which showed diffuse large B-cell lymphoma. The patient was then referred for whole-body F-18 fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) imaging which showed multiple hypermetabolic foci extending along the left inguinal canal to the retroperitoneum and the left perinephric space, suggesting direct contiguous spread of the tumor along the gonadal vessels, a form of metastasis unique to primary testicular lymphoma, and demonstrated for the first time on FDG PET/CT imaging.

Abstract Background Accurate staging of non-small cell lung cancer is key in treatment planning and prediction of prognosis. We investigated the correlation between the maximum standardized uptake value (SUVmax) retention index (RI) of the primary tumor and lymph node metastasis in non-small cell lung carcinoma. We also evaluated the tendencies according to the histological types. Methods We retrospectively evaluated 218 non-small cell lung cancer (NSCLC) tumors from 217 patients who underwent preoperative fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) followed by lung surgery and lymph node resection between July 2015 and August 2020. All primary tumors were calculated as the SUVmax at 50 min (SUVmaxearly [SUVmaxe]) and 120 min (SUVmaxdelayed [SUVmaxd]), and RI. The clinicopathological factors of interest were compared based on lymph node metastasis status and NSCLC histopathological subtype. Results The median SUVmaxe and SUVmaxd of the primary tumors were 3.3 and 4.2, respectively, and the median RI was 0.25. The RI was significantly higher in the pN(+) (n = 44) group (0.30) compared to the pN0 (n = 174) group (0.24) (p = 0.01). In patients with adenocarcinoma (n = 145), the RI was also significantly higher in the pN(+) (n = 29) group (0.29) compared to the pN0 (n = 116) group (0.16) (p

Background: Accurate staging of non-small cell lung cancer is key in treatment planning and prediction of prognosis. We investigated the correlation between the maximum standardized uptake value (SUVmax) retention index (RI) of the primary tumor and lymph node metastasis in non-small cell lung carcinoma. We also evaluated the tendencies according to the histological types. Methods: We retrospectively evaluated 218 non-small cell lung cancer (NSCLC) tumors from 217 patients who underwent preoperative fluorodeoxyglucose-positron emission tomography/computed tomography (PET/CT) followed by lung surgery and lymph node resection between July 2015 and August 2020. All primary tumors were calculated as the SUVmax at 50 min (SUVmaxearly [SUVmaxe]) and 120 min (SUVmaxdelayed [SUVmaxd]), and RI. The clinicopathological factors of interest were compared based on lymph node metastasis status and NSCLC histopathological subtype. Results: The median SUVmaxe and SUVmaxd of the primary tumors were 3.3 and 4.2, respectively, and the median RI was 0.25. The RI was significantly higher in the pN(+) (n = 44) group (0.30) compared to the pN0 (n = 174) group (0.24) (p = 0.01). In patients with adenocarcinoma (n = 145), the RI was also significantly higher in the pN(+) (n = 29) group (0.29) compared to the pN0 (n = 116) group (0.16) (p < 0.01). A high RI of the primary tumor was an independent risk factor for lymph node metastasis, particularly in patients with adenocarcinoma (odds ratio: 12.30, p < 0.05). Conclusions: The RI of primary NSCLC tumors can help predict lymph node metastases, particularly in patients with adenocarcinoma. [ABSTRACT FROM AUTHOR]

Purpose: Fluorine-18 (18F)-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 (68Ga)- somatostatin analog (SSA) PET/CT imaging have been increasingly used in ectopic adrenocorticotropic hormone syndrome (EAS); however, the diagnostic efficacies of these two methods in patients with EAS remain unclear. Our study aimed to compare the diagnostic efficacies of 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT in EAS. Methods: The clinical and imaging data of 68 patients with EAS who underwent 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT examinations from December 2016 to April 2021 were analyzed retrospectively, and the diagnostic efficacies of these methods were compared. Results: In 37 cases, imaging was performed to locate the primary tumor lesion (localization group), and in 31 to evaluate tumor load or metastasis (staging group). Primary tumors were detected in 48.65% (18/37) of the localization group patients. According to scan-based analysis, the tumor lesion detection rates and false positive rates of 18F-FDG PET/CT imaging and 68Ga-DOTANOC PET/CT imaging were 18.92% vs. 45.95% (p < 0.05) and 21.62% vs. 2.70% (p < 0.05) respectively. For lesion-based analysis, the tumor lesion detection rates and false positive rates were 24.13% vs. 58.62% (p >0.05) and 31.04% vs. 3.45% (p < 0.05). In 90.32% (28/31) of the staging group patients, 286 of 292 lesions were confirmed as tumor lesions. Based on scan analysis, the detection rates and false positive rates of 18F-FDG PET/CT imaging and 68Ga-DOTANOC PET/ CT imaging were 83.87% vs. 67.74% (p > 0.05) and 12.90% vs. 9.68% (p > 0.05) respectively. Based on lesion analysis, the detection rate and false positive rates were 93.84% vs. 54.80% (p < 0.05) and 1.37% vs. 1.03% 1(p > 0.05). Conclusion: 68Ga-DOTANOC PET/CT imaging may be more suitable than 18F-FDG PET/CT for identifying the primary tumor in patients with EAS, while 18F-Frontiers FDG PET/CT may be more advantageous than 68Ga-DOTANOC PET/CT for patients with suspected metastasis. [ABSTRACT FROM AUTHOR]

PurposeFluorine-18 (18F)-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 (68Ga)-somatostatin analog (SSA) PET/CT imaging have been increasingly used in ectopic adrenocorticotropic hormone syndrome (EAS); however, the diagnostic efficacies of these two methods in patients with EAS remain unclear. Our study aimed to compare the diagnostic efficacies of 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT in EAS.MethodsThe clinical and imaging data of 68 patients with EAS who underwent 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT examinations from December 2016 to April 2021 were analyzed retrospectively, and the diagnostic efficacies of these methods were compared.ResultsIn 37 cases, imaging was performed to locate the primary tumor lesion (localization group), and in 31 to evaluate tumor load or metastasis (staging group). Primary tumors were detected in 48.65% (18/37) of the localization group patients. According to scan-based analysis, the tumor lesion detection rates and false positive rates of 18F-FDG PET/CT imaging and 68Ga-DOTANOC PET/CT imaging were 18.92% vs. 45.95% (p < 0.05) and 21.62% vs. 2.70% (p < 0.05) respectively. For lesion-based analysis, the tumor lesion detection rates and false positive rates were 24.13% vs. 58.62% (p >0.05) and 31.04% vs. 3.45% (p < 0.05). In 90.32% (28/31) of the staging group patients, 286 of 292 lesions were confirmed as tumor lesions. Based on scan analysis, the detection rates and false positive rates of 18F-FDG PET/CT imaging and 68Ga-DOTANOC PET/CT imaging were 83.87% vs. 67.74% (p > 0.05) and 12.90% vs. 9.68% (p > 0.05) respectively. Based on lesion analysis, the detection rate and false positive rates were 93.84% vs. 54.80% (p < 0.05) and 1.37% vs. 1.03%(p > 0.05).Conclusion68Ga-DOTANOC PET/CT imaging may be more suitable than 18F-FDG PET/CT for identifying the primary tumor in patients with EAS, while 18F-FDG PET/CT may be more advantageous than 68Ga-DOTANOC PET/CT for patients with suspected metastasis.

Cervical cancer is the second most common cancer after breast cancer and the third most common cause of cancer-related death followed by breast and lung cancers among women worldwide. advances in diagnostic imaging techniques provide better assessment of regional and distant cervical cancer metastasis. the use of contrast-enhanced ultrasound is a revolutionary imaging modality; it has several advantages over ct: no radiation exposure, nephrotoxicity, obtaining real-time information, relatively low cost and ease of use. currently, the contrast agent sonoVue is widely used in ultrasound imaging of liver, kidneys and pancreas lesions, as well as for closed abdominal injuries, multiple organ failure, breast and prostate cancers, etc. However, the role of contrast-enhanced ultrasound in gynecology is not clearly established. one of the most effective tools for the detection of locally advanced cervical cancer is mRi, which is used mainly to determine the local extent of the tumor. However, the use of functional mRitechniques has not yet been included in the standards. cervical cancer tissue has been found to show significantly lower diffusion-weighted imaging (dWi) values than normal cervical tissue, thus facilitating the detection of tumor and its spread. dWiis also used for differentiating changes after biopsy from residual tumor and for identifying small lymph nodes. the pEt/cttechnique combines the metabolic images of pEtwith anatomical images of ctand is more accurate than high resolution ctalone, especially in determining the involvement of regional lymph nodes and distant organs. 18-Fdg-pEt/cthas been successfully used for accurate staging of the disease (especially late stage), assessment of treatment response, radiotherapy planning, and detection of disease progression. in patients with advanced stages of cervical cancer (iiBiV stage), the 18-Fdg-pEt/ ctfindings can determine the treatment strategy in most cases, primarily due to high sensitivity (75–100 %) and specificity (87–100 %) in the detection of lymph node metastases.

Main teaching point: Solitary necrotic nodules of the liver can be multiple and usually appear as hypovascular nodules mimicking hepatic metastases, but they are relatively small and located in the subcapsular areas of the liver. We report a very rare case of multiple solitary necrotic nodules of the liver mimicking hepatic metastases in a patient with previous history of lung cancer. The lesions appeared as low-attenuated or low-signal intensity nodules with thin rim enhancement on both contrast-enhanced computed tomography (CT) and magnetic resonance (MR) imaging, making them difficult to differentiate from hepatic metastases. This rare benign entity should be kept in mind, especially when lesions are small and located in the subcapsular areas of the liver.

Summary: Metabolic tumour volume (MTV) and total lesion glycolysis (TLG) are positron‐emission tomography/computed tomography (PET/CT) variables for predicting multiple myeloma's (MM) outcome. We retrospectively investigated and compared the predictive value of MTV, TLG and high‐risk PET/CT variables in clinical practice in 185 patients with newly diagnosed symptomatic MM. High‐risk PET/CT findings were defined as the presence of at least one of the following: more than three focal lesions, maximum standardised uptake value (SUVmax) >4·2 and extramedullary disease. MTV was defined as the volume of myeloma lesions visualised on PET/CT with SUV ≥ 2·5. TLG was calculated as the sum of the product of the average SUV and MTV of all lesions. The mortality prediction optimal cut‐off values for MTV and TLG were 56·4 cm3 and 166·4 g, respectively. High‐burden MTV (≥56·4 cm3), TLG (≥166·4 g) and high‐risk PET/CT findings differed significantly in progression‐free survival (PFS) and overall survival (OS). High‐burden MTV and TLG findings also predicted survival outcomes in young patients (age <75 years) and patients with high‐risk chromosomal abnormalities. High‐burden MTV and TLG independently predicted both worse PFS and OS. Pre‐treatment MTV and TLG independently predicted survival outcomes in clinical practice and may be more useful than high‐risk PET/CT variables. [ABSTRACT FROM AUTHOR]

In patients with well-differentiated papillary thyroid carcinoma (PTC), late recurrence is very rare. It is unusual that18F-fluorodeoxyglucose positron-emission tomography/computed tomography (PET/CT) shows hypermetabolic lesions in patients with well-differentiated PTC metastases. We demonstrate an exceptional case exhibiting a first relapse 37 years after hemithyroidectomy to treat PTC. Recurrent metastasis of a PTC should be considered as a differential diagnosis even if the elapsed time from the initial treatment is great. A left cervical lymphadenopathy, which exceptionally exhibited a hypermetabolic lesion on PET/CT, should be considered a metastatically well-differentiated PTC. [ABSTRACT FROM AUTHOR]

Objective: To retrospectively evaluate contribution of F-18 fluorodeoxyglucose positron-emission tomography/computed tomography (18FDG-PET/CT) to re-staging of upper urinary tract urothelial carcinoma (UTUC). Materials and Methods: This study included a total of 17 patients (12 males and 5 females), who underwent nephroureterectomy due to UTUC and 18FDG-PET/CT between July 2007 and April 2015. The mean age of the patients was 64.3±9.96 years (range: 45-79). 18FDG-PET/CT was performed for re-staging 6-24 months after nephroureterectomy (mean: 18 months). Nearly 1 hour after intravenous injection of 555 MBq of F-18 FDG, the patients underwent whole-body PET scanning from the skull base to the upper thighs after 6 hours of fasting, and nearly 1 hour after all body CT scanning performed in the craniocaudal direction. By using CT data for attenuation correction, FDG-PET images were reconstructed. Results: 18FDG-PET/CT scans proved negative findings in three patients (17.7%) and positive findings in 14 patients (82.3%). Suspicious recurrent or metastatic lesions were confirmed by histopathology or clinical follow-up. Sensitivity of 18FDG-PET/CT was 93% and the specificity was 75%. Conclusion: 18FDG-PET/CT defines local recurrence and far metastases with high specificity in re-staging of operated UTUC. It is thought that the procedure could play an important role in decisions regarding radiotherapy or chemotherapy and post-operative follow-up after the operation and could affect the whole decision-making process.

Lung cancer, the most frequently diagnosed cancer worldwide, is the leading cause of cancer-associated deaths. In recent years, significant progress has been achieved in basic and clinical research concerning the epidermal growth factor receptor (EGFR), and the treatment of lung adenocarcinoma has also entered a new era of individualized, targeted therapies. However, the detection of lung adenocarcinoma is usually invasive. 18F-FDG PET/CT can be used as a noninvasive molecular imaging approach, and radiomics can acquire high-throughput data from standard images. These methods play an increasingly prominent role in diagnosing and treating cancers. Herein, we reviewed the progress in applying 18F-FDG PET/CT and radiomics in lung adenocarcinoma clinical research and how these data are analyzed via traditional statistics, machine learning, and deep learning to predict EGFR mutation status, all of which achieved satisfactory results. Traditional statistics extract features effectively, machine learning achieves higher accuracy with complex algorithms, and deep learning obtains significant results through end-to-end methods. Future research should combine these methods to achieve more accurate predictions, providing reliable evidence for the precision treatment of lung adenocarcinoma. At the same time, facing challenges such as data insufficiency and high algorithm complexity, future researchers must continuously explore and optimize to better apply to clinical practice., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ge, Gao, Niu, Shi, Shao, Wang and Shao.)

In recent years, the emergence of prostate-specific membrane antigen (PSMA)-targeted positron-emission tomography (PET) imaging has brought about a paradigm shift in the way that prostate cancer (PCa) is imaged in many parts of the world. Although PSMA-targeted PET imaging has been demonstrated to be a highly sensitive and specific imaging modality for the identification of sites of PCa, its clinical utility hinges on the ability of imaging specialists and their clinical colleagues to recognize potential false-positive sources of uptake and to tailor therapy based on that recognition. In this manuscript, we report the case of a 74-year-old male with a history of recurrent PCa who was referred for a restaging PSMA-targeted18F-DCFPyL PET/computed tomography (PET/CT). PET images demonstrated low level but focal and definitive uptake in the left femoral head. This uptake corresponded to sclerotic changes on CT whose morphology was most compatible with avascular necrosis without femoral head collapse. In the presented case, the integrated assessment of the CT imaging together with the PET findings was fundamental to avoid misinterpretation of the left femur finding as metastatic disease, which would have ultimately altered the clinical management of the patient. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) can present with various forms and can occasionally be mistaken for malignancy. Hereby, we report a 53-year-old man diagnosed and treated for Burkitt's lymphoma in 2009 who achieved a complete remission confirmed by a computed tomography (CT) scan. During the follow-up 2 years later, he complained of left hip pain that warranted investigation with magnetic resonance imaging and whole-body 18F-fludeoxyglucose-positron emission tomography (FDG-PET)/CT which showed a benign lesion in the left hip associated with multiple lymph nodes in the chest and abdomen not amenable for biopsy. A follow-up PET/CT scan a few months later showed intense tracer uptake in the lymph nodes with size progression and appearance of new lymph nodes suspicious of lymphoma relapse. The patient was asymptomatic, and all investigations including viral and connective tissue disease studies were negative. Also the tuberculin skin test and QuantiFERON were negative. Lymph node biopsy was planned; however, the patient presented a few days earlier with fever, headache and photophobia. Cerebrospinal fluid (CSF) examination confirmed meningitis with lymphocytic pleocytosis and elevated protein. The CSF Gram stain, culture, viral and acid-fast bacilli were negative. CSF flow cytometry and cytopathology confirmed polyclonal lymphocytosis and suggested reactive causes. CSF TB culture grew Mycobacterium tuberculosis. Mediastinal lymph node biopsy also confirmed TB lymphadenitis. Four antituberculosis drugs were started. One year later, a PET/CT scan showed regression of all the involved lymph nodes. This case highlights the importance of excluding TB in patients with suspected malignancy, especially if they belong to endemic regions, and the increasing role of 18F-FDG-PET/CT in the early detection of extrapulmonary TB.

Background: Primary sarcoma of the prostate is extremely rare and accounts for 0.1% of all prostate cancers. This type of cancer is associated with poor prognosis due to aggressive biological behavior. The World Health Organization histologically classified prostate sarcomas as stromal tumor of unknown malignant potential (STUMP) and stromal sarcoma. Patients and Methods: A 39-year-old patient presented with lower urinary tract symptoms over the last few months. On digital rectal examination, the right lobe of the prostate was diffusely hard on palpation. Prostate-specific antigen was 0.5 ng/ml. A biopsy specimen was obtained with the guidance of transrectal ultrasonography. Immunohistochemical examination revealed positive staining for vimentin, actin, and desmin. Results: 18 F-fluorodeoxyglucose-positron-emission tomography/computed tomography scans obtained for staging purposes with the diagnosis of primary spindle cell carcinoma of the prostate revealed widespread lung and liver metastases. A doxorubicin-based systemic chemotherapy (CTx) was initiated. Conclusion: Spindle sarcomas of the prostate have quite aggressive nature and they have high potential to metastase. Average life expectancy is

Aim: In newly diagnosed carcinoma breast cancer patients, comparing conventional staging and 18F-fluorodeoxyglucose positron-emission tomography-computed tomography (18F-FDG PET/CT) staging. Materials and Methods: This was a retrospective observational study. A total of 171 new diagnosed carcinoma breast patients who underwent staging 18F-FDG PET/CT scan and routine conventional imaging including mammosonography of breast and axilla, chest X-ray, ultrasound sonography abdomen, and bone scan were included in the study. Staging was done according to the American Joint Committee on Cancer staging (tumor-node-metastasis). Changes in staging and management with 18F-FDG PET/CT scan were assessed. Results: Overall PET/CT upstaged in 22.2% of cases and changed management in 15.78% of cases. PET/CT upstaged in three of eight cases in Stage IA patients but changed management in only one case. In Stage IIA, of 31 patients PET/CT upstaged in two patients (6.45%). In Stage IIB, of 45 patients PET/CT upstaged in six patients (13.3%). In Stage IIIA, of 22 patients PET/CT upstaged in six patients (27.2) and in five patients there is a change in management. In Stage IIIB, of 43 patients PET/CT upstaged in 21 patients (48.8%) with change in management in 13 patients (25.5%). Conclusion: 18F-FDG PET/CT scan can be helpful in a significant number of patients with Stage IIB and above in upstaging and changing management. [ABSTRACT FROM AUTHOR]

Purpose: To determine the impact of Gallium-68-labled prostate-specific membrane antigen positron-emission tomography/computed tomography ([68Ga]PSMA PET/CT) on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer.Methods: A total of 106 patients with prostate cancer scheduled for radiation therapy underwent 120 [68Ga]PSMA PET/CT scans prior to radiotherapy treatment. In 20 cases, patients underwent [68Ga]PSMA PET/CT for primary therapy (PT), 75 cases were referred for biochemical relapse after surgery (RL), and 25 cases were intended for palliative treatment of localized metastases (MD). We retrospectively compared the impact of [68Ga]PSMA PET/CT on lesion detection and treatment decision to CT alone.Results: [68Ga]PSMA PET/CT revealed a total of 271 positive lesions, whereas CT detected 86 lesions (32%). Overall, the radiotherapy regime was changed in 55 of 120 cases (46%) based on the higher detection rate of [68Ga]PSMA PET/CT: in 15% of cases with PT, in 43% of cases with RL, and in 44% of cases with MD.Conclusion: [68Ga]PSMA PET/CT is superior to CT alone for lesion detection in prostate cancer, thereby significantly impacting on radiotherapy planning for primary disease, biochemical cancer relapse, and advanced disease of prostate cancer. [ABSTRACT FROM AUTHOR]

Recently, 68 Ga-labeled prostate-specific membrane antigen (PSMA)–ligand positron-emission tomography (PET) imaging has been shown to improve detection rates in recurrent prostate cancer (PC). However, published studies include only small patient numbers at low prostate-specific antigen (PSA) values. For this study, 272 consecutive patients with biochemical recurrence after radical prostatectomy and PSA value between 0.2 and 1 ng/ml were included. The 68 Ga-PSMA-ligand PET/computed tomography (CT) was evaluated, and detection rates were determined and correlated to various clinical variables using univariate and multivariable analyses. Subgroups of patients with very low (0.2–0.5 ng/ml) and low (>0.5–1.0 ng/ml) PSA values were analyzed. In total, lesions indicative of PC recurrence were detected in 55% (74/134) and 74% (102/138) with very low and low PSA values, respectively. Main sites of recurrence were pelvic or retroperitoneal lymph nodes metastases, followed by local recurrence and bone metastases with higher probability in the low versus very low PSA subgroup. Detection rates significantly increased with higher PSA values, primary pT ≥ 3a, primary pN+ disease, grade group ≥4, previous radiation therapy, and concurrent androgen deprivation therapy (ADT) in univariate analysis. In a multivariable logistic regression model, concurrent ADT and PSA values were identified as most relevant predictors of positive 68 Ga-PSMA-ligand PET/CT. Further, prediction nomograms were established, which may help in estimating pretest PSMA-ligand PET positivity in clinical practice. Patient summary In our study, 68 Ga-labeled prostate-specific membrane antigen (PSMA)–ligand positron-emission tomography (PET)/computed tomography (CT) detected recurrent disease after radical prostatectomy in 55% (74/134) and 74% (102/138) of patients with very low (0.2–0.5 ng/ml) and low (>0.5–1.0 ng/ml) prostate-specific antigen values, respectively. On the basis of these data, it seems reasonable to perform 68 Ga-PSMA-ligand PET/CT also in patients with early biochemical recurrence, as it can tailor further therapy decisions (eg, local vs systemic treatment). The established prediction nomograms can further assist urologists in discussions on the use of 68 Ga-PSMA-ligand PET/CT with their patients in specific clinical settings. [ABSTRACT FROM AUTHOR]

Aim: With increased clinical indications for positron-emission tomography/computed tomography (PET/CT) and repeated PET/CT scans, there is a need to reduce the radiation burden to the patient, professionals as well as public. This requires a redefining of the workflow and the 18-F-fluorodeoxyglucose (18F-FDG) administered activity. The objective of our study is to observe the impact of strike out reduction of administered activity on the radiation exposure to personnel and public, as well as the absorbed dose to the patient with no compromise on image quality by increasing the image acquisition time. Materials and Methods: Nineteen patients evaluated in this study (11 males, 8 females) were put into two groups, namely, A and B. Patients in Group A (n = 10) were administered with 18F-FDG equivalent to the recommended dose (7-8 MBq/kg body weight) whereas patients in Group B (n = 9) were administered with 18F-FDG equivalent to half the recommended dose (3-4MBq/kg body weight). The exposure rates from the patients at the body surface and 100 cm distance were measured immediately and 1 h postinjection. Results: The average surface dose rate and 100 cm dose rate of the adult patients immediately postinjection for patients of Group A were 0.94 ± 0.19 mSv/h and 0.057 ± 0.007 mSv/h, and for Group B were 0.34 ± 0.24 mSv/h and 0.031 ± 0.01 mSv/h. Conclusion: This study suggests that reduction in injected 18F-FDG activity reduces the radiation exposure rate from the patient, absorbed dose to the patient with reportable image quality. [ABSTRACT FROM AUTHOR]

Positron-emission tomography/computed tomography (PET/CT) has improved cyst infection (CI) management in autosomal dominant polycystic kidney disease (ADPKD). The determinants of kidney and/or liver involvement, however, remain uncertain. In this study, we evaluated clinical and imaging factors associated with CI in kidney (KCI) and liver (LCI) in ADPKD. A retrospective cohort study was performed in hospital-admitted ADPKD patients with suspected CI. Clinical, imaging and surgical data were analyzed. Features of infected cysts were evaluated by PET/CT. Total kidney (TKV) and liver (TLV) volumes were measured by CT-derived multiplanar reconstruction. CI was detected in 18 patients who experienced 24 episodes during an interval of 30 months (LCI in 12, KCI in 10 and concomitant infection in 2). Sensitivities of CT, magnetic resonance imaging and PET/CT were 25.0, 71.4, and 95.0%. Dysuria (P

Objective: To retrospectively evaluate contribution of F-18 fluorodeoxyglucose positron-emission tomography/computed tomography (18FDG-PET/CT) to re-staging of upper urinary tract urothelial carcinoma (UTUC). Materials and Methods: This study included a total of 17 patients (12 males and 5 females), who underwent nephroureterectomy due to UTUC and 18FDG-PET/CT between July 2007 and April 2015. The mean age of the patients was 64.3±9.96 years (range: 45-79). 18FDG-PET/CT was performed for re-staging 6-24 months after nephroureterectomy (mean: 18 months). Nearly 1 hour after intravenous injection of 555 MBq of F-18 FDG, the patients underwent whole-body PET scanning from the skull base to the upper thighs after 6 hours of fasting, and nearly 1 hour after all body CT scanning performed in the craniocaudal direction. By using CT data for attenuation correction, FDG-PET images were reconstructed. Results: 18FDG-PET/CT scans proved negative findings in three patients (17.7%) and positive findings in 14 patients (82.3%). Suspicious recurrent or metastatic lesions were confirmed by histopathology or clinical follow-up. Sensitivity of 18FDG-PET/CT was 93% and the specificity was 75%. Conclusion: 18FDG-PET/CT defines local recurrence and far metastases with high specificity in re-staging of operated UTUC. It is thought that the procedure could play an important role in decisions regarding radiotherapy or chemotherapy and post-operative follow-up after the operation and could affect the whole decision-making process. [ABSTRACT FROM AUTHOR]

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Carcinoma of the sigmoid colon presenting in an inguinoscrotal hernia is uncommon. Many of the cases seen in literature were diagnosed only intraoperatively, as most of them had misleading presentations. We report a case of carcinoma of the sigmoid colon in an incarcerated inguinoscrotal hernia with imaging findings of 18F-FDG PET/CT along with a brief review of the literature. [ABSTRACT FROM AUTHOR]

One of the most important benign tumors in neurofibromatosis type 1 (NF1) is plexiform neurofibroma, and there is a risk of developing malignant peripheral nerve sheath tumor (MPNST) throughout life approximately 10%. However lesion characterization by anatomical imaging methods are not possible. Because of that most of cases goes to biopsy. Using of fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) for lesion characterization can be helpful in NF1 patients. We aimed to present an example of the efficacy of FDG-PET/CT in distinguishing benign neurofibroma from MPNST. A 6-year-old male patient who had NF1 admitted to emergency service due to high fever. Acute upper respiratory tract infection was diagnosed; antipyretic and abundant fluid intake was suggested. When high fever continued, the patient referred to our hospital on detection of axillary lymphadenopathy. Leukocytosis was detected in patient's blood count. Sedimentation was 54 mm/h, C-reactive protein 166 g/L, and lactate dehydrogenase 276U/L. Blood and throat cultures did not show pathogenic bacteria. In serological tests, VZV-IgG, EBV-VCA-IgG, and CMV-IgG were avidite positive; Hepatitis B Ag, Anti-HIV, Anti-HAV IgG and IgM, Anti-HCV, EBV-VCA IgM, and VZV-IgM were negative. Based on these results, cervical and thoracic contrast-enhanced computed tomography was performed on preliminary diagnosis of MPNST. Solid lesions with rounded margins, large one being 49 mm in size, that extend from superior mediastinum to posterior mediastinum, left axillary region, and left part of neck were detected, and they were surrounding the vascular structures. Since neurofibroma, MPNST, and lymphoma could not be distinguished, patient referred to FDG-PET/CT scanning. In FDG-PET/CT, highest lesion maximum standardized uptake value (SUVmax) was 1.5; SUVmaxlesion/SUVmaxliver 1.0, and SUVmax/ SUV mean liver 1.5. Biopsy from mediastinal and axillary region did not have LN structure and was positive for S-100 immunostaining, and patient was diagnosed as benign neurofibroma. We believe that there is no need for biopsy in lesions considered benign based on FDG-PET/CT parameters. [ABSTRACT FROM AUTHOR]

Sarcoidosis is a systemic granulomatous disorder of unknown origin that affects the lungs and mediastinal lymph nodes in most patients. The coexistence of sarcoidosis and breast cancer has been reported. An unfortunate consequence of the presence of both entities in the same patient is the risk of misdiagnosis. We report the case of a 70-year-old female with T1N0 cancer of the right breast that was initially diagnosed as stage IV because of mediastinal positron-emission tomography -positive lymphadenopathy. Biopsy of a mediastinal lymph node allowed us to diagnose sarcoidosis and correctly stage her disease as stage I breast cancer. [ABSTRACT FROM AUTHOR]

In the last 10 years, Fluorine-18 fluorodeoxyglucose (FDG) Positron Emission Tomography (PET) scan has been widely adopted in thoracic oncology, showing high accuracy in staging and restaging. The aim of this review was to focus on the results of PET scan use in the evaluation of thoracic malignancies. The literature search was performed on January 2015 in PubMed and Google Academic. The search was restricted to publications in English, using in the same string the word "PET" with different thoracic tumors. From 3000 papers initially selected, the irrelavant articles eliminated and then approximately 100 manuscripts were fully analyzed. In conclusion, positron emmision tomography/ computed tomography (PET-CT) has established itself as an important step in the evaluation of patients with thoracic malignancies. Further evaluation and come into use of newer PET tracers and simultaneous Magnetic Resonance Imaging (MRI) with PET (PET/MR) imaging will offer additional options in thoracic oncology in future. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) can present with various forms and can occasionally be mistaken for malignancy. Hereby, we report a 53-year-old man diagnosed and treated for Burkitt's lymphoma in 2009 who achieved a complete remission confirmed by a computed tomography (CT) scan. During the follow-up 2 years later, he complained of left hip pain that warranted investigation with magnetic resonance imaging and whole-body 18F-fludeoxyglucose-positron emission tomography (FDG-PET)/CT which showed a benign lesion in the left hip associated with multiple lymph nodes in the chest and abdomen not amenable for biopsy. A follow-up PET/CT scan a few months later showed intense tracer uptake in the lymph nodes with size progression and appearance of new lymph nodes suspicious of lymphoma relapse. The patient was asymptomatic, and all investigations including viral and connective tissue disease studies were negative. Also the tuberculin skin test and QuantiFERON were negative. Lymph node biopsy was planned; however, the patient presented a few days earlier with fever, headache and photophobia. Cerebrospinal fluid (CSF) examination confirmed meningitis with lymphocytic pleocytosis and elevated protein. The CSF Gram stain, culture, viral and acid-fast bacilli were negative. CSF flow cytometry and cytopathology confirmed polyclonal lymphocytosis and suggested reactive causes. CSF TB culture grew Mycobacterium tuberculosis. Mediastinal lymph node biopsy also confirmed TB lymphadenitis. Four antituberculosis drugs were started. One year later, a PET/CT scan showed regression of all the involved lymph nodes. This case highlights the importance of excluding TB in patients with suspected malignancy, especially if they belong to endemic regions, and the increasing role of 18F-FDG-PET/CT in the early detection of extrapulmonary TB. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Mucinous tubular and spindle cell carcinoma of the kidney (MTSCC-K) is an extremely rare carcinoma of the kidney, which develops by malignant differentiation of the collecting ducts or the loop of Henle. The tumor can occur at all ages, with 4 times higher prevalence in females than in males. A 62-year-old female patient presented with an asymptomatic mass lesion in the left kidney. The ultrasound revealed a hyperechogenic mass lesion measuring 4 cm in diameter and centrally located in the left kidney. Computed tomography (CT) revealed an isodense mass lesion measuring 4 cm in diameter and posterolaterally located in the left kidney. Magnetic resonance imaging revealed a renal mass of 4 cm in diameter with hypervascular contrast uptake. For primary staging, 18F-fluorodeoxyglucose-positron-emission tomography (18FDG-PET)/CT revealed left renal cell carcinoma (RCC) with a maximum standard uptake value of 6.7. The patient underwent transperitoneal radical nephrectomy. The immunohistochemical examination revealed MTSCC-K. 18FDG-PET/CT provides 81-89% sensitivity and 83-100% specificity in primary staging of the renal cancers, in diagnosing metastatic RCC, and monitoring the response to therapy. Its use in the staging of MTSCC of the kidney has not been previously described in the literature. This case highlights the usefulness of, 8FDG-PET/CT in the staging of this rare tumor. [ABSTRACT FROM AUTHOR]

Background: Primary sarcoma of the prostate is extremely rare and accounts for 0.1% of all prostate cancers. This type of cancer is associated with poor prognosis due to aggressive biological behavior. The World Health Organization histologically classified prostate sarcomas as stromal tumor of unknown malignant potential (STUMP) and stromal sarcoma. Patients and Methods: A 39-year-old patient presented with lower urinary tract symptoms over the last few months. On digital rectal examination, the right lobe of the prostate was diffusely hard on palpation. Prostate-specific antigen was 0.5 ng/ml. A biopsy specimen was obtained with the guidance of transrectal ultrasonography. Immunohistochemical examination revealed positive staining for vimentin, actin, and desmin. Results: 18F-fluorodeoxyglucose-positron-emission tomography/computed tomography scans obtained for staging purposes with the diagnosis of primary spindle cell carcinoma of the prostate revealed widespread lung and liver metastases. A doxorubicin-based systemic chemotherapy (CTx) was initiated. Conclusion: Spindle sarcomas of the prostate have quite aggressive nature and they have high potential to metastase. Average life expectancy is <1 year and the prognosis is poor. CTx and radiation therapy can't yield curative effects due to poor differentiation. [ABSTRACT FROM AUTHOR]

Background: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. The tumor size and mitotic count, typical risk category factors, are difficult to determine preoperatively. This study aimed to evaluate the usefulness of preoperative 18F-fluoro-2-deoxyglucose positron-emission tomography/computed tomography (18FDG-PET/CT) for predicting the malignant potential of GISTs by analyzing the correlation between the maximum standardized uptake value (SUVmax) and postoperative factors. Methods: Thirty consecutive patients underwent surgery after preoperative 18FDG-PET/CT and were diagnosed with pathologically confirmed GIST. The tumor size, mitotic count, MIB-1 index and National Institutes of Health (NIH) risk category were compared with SUVmax. Results: Significant correlations between SUVmax and tumor size and NIH risk category were determined. The sensitivity and specificity of SUVmax for predicting the risk of malignancy were 85.7 and 62.5%, respectively. The optimal cut-off value for SUVmax was 3.0 between patients classified into low-risk and high-risk malignancy groups. There was no significant correlation between SUVmax and mitotic count or MIB-1 index. Multivariate analysis indicated that SUVmax was the only predictive risk factor in the high-risk malignancy group. Conclusions: 18FDG-PET/CT is useful for assessing the malignant potential and bioactivity of GISTs. When SUVmax is >3.0, the tumor must be resected even if it measures <2 cm, because of its high malignant potential. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective According to the current treatment protocol of the Cooperative Osteosarcoma Study, it is mandatory to determine the histological response to neoadjuvant chemotherapy treatment before surgical removal of the tumor, particularly if a limb salvage procedure is planned. The aim of this systematic, retrospective study was to evaluate the ability of 2-(18 F) fluoro-2-deoxy- D-glucose positron-emission tomography/computed tomography to predict chemotherapy response of osteosarcoma and to identify a simple promising method for noninvasive evaluation of neoadjuvant chemotherapy response in osteosarcoma. Methods The PubMed database was searched to identify and analyze relevant published reports. In particular, correlations between tumor-to-background ratio ( TBR), standard uptake value ( SUV) and histological response to chemotherapy were assessed. Results It was found that good responses are achieved in patients with TBR after chemotherapy ( TBR2)/ TBR before chemotherapy ( TBR1) < 0.470 (positive predictive value [ PPV] = 92.31%, negative predictive value [ NPV] = 82.76%, sensitivity [ S] = 87.80%, specificity [ SP] = 88.89%), whereas poor responses occur in patients with SUV after chemotherapy/before chemotherapy ( SUV2/ SUV1) > 0.396 ( PPV = 73.68%, NPV = 73.33%, S = 63.64%, SP = 81.48%). Conclusion Changes in TBR are better predictors of chemotherapy response than SUV in osteosarcoma patients. Therefore, we believe that choice of surgical strategy is optimally based on changes in TBR. [ABSTRACT FROM AUTHOR]

Objective: In this study, we aimed to explore prognostic importance of definition of preoperative metabolic tumor volume in esophageal cancer patients. Methods: 22 patients who have histologically proven stage IIA-III esophageal cancer and underwent 18F-FDG PET/CT for preoperative staging of disease were included to the study. After 18F-FDG PET/CT, all the patients underwent surgery within 4 weeks period. Patients have been followed up until death or Sept 15th, 2012. Dates of death were recorded for survival analysis. During evaluation of 18F-FDG PET/CT images, metabolic tumor volumes were calculated by drawing the isocontour region of interests from all visually positive FGD uptake lesions. Results: 22 patients (15M, 7F; mean age: 65.1±8.4, min-max:48-80) underwent 18F-FDG PET/CT for preoperative staging of esophageal cancer. Preoperative diagnosis was squamous cell and adeno cancer in 17 (%77) and 5 (%23) patients, respectively. Location of primary tumor is distal, proximal and mid-esophagus in 13 (%59), 6 (%27) and 3 (%13) patients, respectively. Primary tumor of all the patients were FDG avid (mean SUVmax: 18.85±7.0; range: 5.5-35.1). Additionally, 18F-FDG uptake was seen in mediastinal lymph nodes in 13 patients (5.45±8.15; range: 2.6-29.9). Mean metabolic tumor volumes of primary esophageal lesions were calculated as 8.77±8.46cm³ (range: 2.3-34.2). Mean MTV of lymph nodes was 2.44±1.01cm³ (range: 0.4-3.6). Mean total metabolic tumor volume was calculated as 9.99±8.58cm³ (range: 2.3-27.3). 10 patients died during 447±121 days follow-up period. Mean survival time was 11.9±1.5 months (95%CI: 8.99-14.74) for entire patient group. Total metabolic tumor volume had a significant effect on survival (p=0.045) according to Cox proportional hazards regression analysis. One unit increase in MTV caused 1.1 (95%CI:1.003-1.196) fold increase in hazard, at any time. Conclusion: Definition of preoperative metabolic tumor volume has a prognostic value in the prediction of postoperative survival times. Patients who have higher preoperative metabolic tumor volumes could be good candidates for more aggressive chemo-radiation therapy regiments. [ABSTRACT FROM AUTHOR]

Objective: We have compared diffusion-weighted magnetic resonance imaging (DW-MRI) properties of mediastinal lymph nodes in lung cancer patients with positron emission tomography/computed tomography (PET/CT) findings. Patients and Methods: Twenty-one consecutive untreated patients with lung cancer were included. DW-MRI was performed on a 1,5T scanner with b values of 50, 500 and 1000. Additional MR imaging was performed for anatomical correlation. Results: A total of 47 lymph nodes were analyzed. While no correlation was found between minimum apparent diffusion coefficient (ADC) values (ADCmin) of lymph nodes and their maximum standardized uptake values (SUVmax) on PET/CT, ADCmin ratios of lymph nodes to main lesion (ADCmin Node/Lesion) (r = - 0.407; p = 0.005) and lymph node to cerebrospinal fluid (ADCmin Node/CSF) (r = - 0.364; p = 0.012) were correlated with SUVmax. Cutoff values for DW-MRI parameters were determined using ROC analysis. Six lymph nodes were histopathologically examined. Both methods correctly identified one metastatic and two metastasis negative lymph nodes, while staging one lymph node with granulomatous change as metastasis positive. Two metastasis negative lymph nodes, reported as suspicious on PET/CT, were correctly staged on DW-MRI. Conclusion: Our findings indicate that DW-MRI could be at least as valuable as PET/CT in mediastinal staging of patients with lung cancer. [ABSTRACT FROM AUTHOR]

Purpose: Fluorine-18 ( 18 F)-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 ( 68 Ga)-somatostatin analog (SSA) PET/CT imaging have been increasingly used in ectopic adrenocorticotropic hormone syndrome (EAS); however, the diagnostic efficacies of these two methods in patients with EAS remain unclear. Our study aimed to compare the diagnostic efficacies of 18 F-FDG PET/CT and 68 Ga-DOTANOC PET/CT in EAS., Methods: The clinical and imaging data of 68 patients with EAS who underwent 18 F-FDG PET/CT and 68 Ga-DOTANOC PET/CT examinations from December 2016 to April 2021 were analyzed retrospectively, and the diagnostic efficacies of these methods were compared., Results: In 37 cases, imaging was performed to locate the primary tumor lesion (localization group), and in 31 to evaluate tumor load or metastasis (staging group). Primary tumors were detected in 48.65% (18/37) of the localization group patients. According to scan-based analysis, the tumor lesion detection rates and false positive rates of 18 F-FDG PET/CT imaging and 68 Ga-DOTANOC PET/CT imaging were 18.92% vs. 45.95% ( p < 0.05) and 21.62% vs. 2.70% ( p < 0.05) respectively. For lesion-based analysis, the tumor lesion detection rates and false positive rates were 24.13% vs. 58.62% ( p > 0.05) and 31.04% vs. 3.45% ( p < 0.05). In 90.32% (28/31) of the staging group patients, 286 of 292 lesions were confirmed as tumor lesions. Based on scan analysis, the detection rates and false positive rates of 18 F-FDG PET/CT imaging and 68 Ga-DOTANOC PET/CT imaging were 83.87% vs. 67.74% ( p > 0.05) and 12.90% vs. 9.68% ( p > 0.05) respectively. Based on lesion analysis, the detection rate and false positive rates were 93.84% vs. 54.80% ( p < 0.05) and 1.37% vs. 1.03%( p > 0.05)., Conclusion: 68 Ga-DOTANOC PET/CT imaging may be more suitable than 18 F-FDG PET/CT for identifying the primary tumor in patients with EAS, while 18 F-FDG PET/CT may be more advantageous than 68 Ga-DOTANOC PET/CT for patients with suspected metastasis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zhang, He, Long, Zhang, Wang, Chen, Liu and Zhang.)

Cardiovocal syndrome or Ortner's syndrome is hoarseness voice due to left recurrent laryngeal nerve palsy secondary to nerve compression caused by enlarged cardiovascular structures in the mediastinum. We present here an interesting positron-emission tomography/computed tomography image of a patient suspected to have Takayasu's aortoarteritis and presenting with hoarseness of voice. [ABSTRACT FROM AUTHOR]

Objective: We aimed to evaluate the value of somatostatin receptor imaging (SRI) with In-111 octreotide and Ga-68 DOTATATE in localizing ectopic ACTH producing tumors. Methods: Nineteen patients who had In-111 octreotide somatostatin receptor scintigraphy (SRS) and/or Ga-68 DOTATATE PET- CT to localize ectopic ACTH producing tumors between the years 2000 and 2012 were included retrospectively in our study. The results of SRI were compared with clinical onset, radiological findings and surgical data of the patients. Results: Sixteen In-111 octreotide SRS and five Ga-68 DOTATATE PET-CT were performed in 19 patients. In eight out of 19 patients, ectopic ACTH secretion site could be detected. In five patients, SRS showed pathologic uptake. In four of these patients, surgery revealed pulmonary carcinoid tumors and in one patient pancreatic neuroendocrine tumor. In one patient, Ga-68 DOTATATE PET-CT revealed pathologic uptake in lung nodule which came out to be pulmonary carcinoid tumor. In another patient who had resection of metastases of atypical carcinoid tumor prior to scans, new metastatic foci were detected both with SRS and Ga-68 DOTATATE PET-CT imaging. In one patient, although SRS was negative, CT which was performed three years later showed a lung nodule diagnosed as pulmonary carcinoid tumor. In 11 patients, ectopic ACTH secretion site could not be detected. In 10 of those patients, scintigraphic and radiological imaging did not show any lesions and in one patient, Ga-68 DOTATATE PET-CT was false positive. Conclusion: SRI has a complementary role with radiological imaging in localizing ectopic ACTH secretion sites. PET-CT imaging with Ga-68 peptide conjugates is a promising new modality for this indication. [ABSTRACT FROM AUTHOR]

Positron emission tomography using fluorodeoxyglucose is a well known diagnostic tool for routine assessment of the patients with carcinoma. Fluorodeoxyglucose uptake, as a marker of glucose metabolism, is increased in malignant conditions as well as infectious and inflammatory processes. In this case report, findings of postoperative changes in the graft on FDG PET/CT were presented in a patient on follow-up for operated renal cell carcinoma and aortic aneurysm graft surgery. The importance of the FDG uptake pattern has been pointed out for differential diagnosis of infectious and non-infectious conditions. [ABSTRACT FROM AUTHOR]

A 64-year old woman with a long standing Sjogren's syndrome was undergoing evaluation for renal transplant surgery when two pulmonary opacities were detected on chest CT. Subsequent biopsy revealed extranodal marginal B-cell non-Hodgkin's lymphoma (NHL). An FDG-PET/CT scan was then performed which demonstrated isolated FDG avid pulmonary involvement. After therapy, FDG-PET/CT scans showed good response to treatment with near complete resolution of FDG avidity. This rare case illustrates the rare pulmonary manifestation of extranodal lymphoma in a patient with Sjogren's syndrome and emphasizes the value of FDG PET/CT in the initial staging and evaluation of response to treatment, which has not previously been published. [ABSTRACT FROM AUTHOR]

Objective: Because the detection of the primary tumour is of importance to optimize the patient's management and allows a targeted therapy, the performance of hybrid positron emission tomography-computed tomography (PET/CT) using fluorodeoxyglucose (FDG) in the detection of primary tumors and unrecognized metastases with cervical lymph node metastases were evaluated in a retrospective study. Material and Methods: Twenty patients with cervical lymph node metastases of unknown primary tumors underwent staging with FDG-PET/CT. All underwent head and neck examinations, computed tomography (CT), and/or magnetic resonance imaging (MRI), panendoscopies, and biopsies of head and neck mucosal sites. The diagnostic accuracy of FDG-PET/CT in detecting primary tumors was compared with that of histopathology and clinical follow-up. The ability of FDG-PET/CT to detect distant metastases was also tested. Results: PET/CT was positive with an increased FDG uptake suggesting the potential primary site in 45% of patients (9/20). PET/CT findings were true positive in 7, true negative in 10, false positive in 2, and false negative in 1 patients, resulting in a sensitivity of 87%, a specificity of 83%, an accuracy of 85%, a positive predictive value of 77% and a negative predictive value of 90%. Also, PET/CT showed distant metastases in seven patients. Conclusion: FDG-PET/CT can be successfully used for the identification of the primary site and distant metastases in patients with cervical lymph node metastases from an unknown primary cancer. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: To estimate the distribution of head and neck squamous cell carcinoma (HNSCC) recurrence after definitive chemoradiation therapy (CRT) among patients who underwent 18F-fluorodeoxyglucose positron-emission tomography and computed tomography (PET/CT) surveillance. Study Design: Retrospective review. Methods: HNSCC patients who underwent definitive CRT from 2001 to 2008 were evaluated for recurrence with serial PET/CT. Patients were excluded if they were previously treated for recurrent disease, were treated with surgery as the primary therapeutic modality, or had inadequate clinical follow-up. Recurrence was defined by histopathologic evidence of tumor. Results: Three hundred eighty-eight patients were studied. Patients in whom recurrence was not detected were followed clinically and radiographically for a median of 27 months. Tumor recurrence was detected in 110 patients. For 37 patients, recurrence was heralded by clinical signs. Among the 73 asymptomatic patients who had a confirmed recurrence, disease was detected by PET/CT between 2 and 43 months, median of 6 months. Forty-five percent of observed asymptomatic recurrences were detected during the first 6 months of surveillance (95% confidence interval [CI], 34%-57%), 79% within the first 12 months (95% CI, 68%-88%), 95% within the first 24 months (95% CI, 87%-98%), and 100% within the first 48 months (95% CI, 95%-100%). Conclusions: Among HNSCC patients followed with PET/CT surveillance, 95% of observed asymptomatic recurrences were detected within 24 months after completing CRT. For patients without clinical signs of recurrence, routine PET/CT surveillance beyond the first 24 months may be of limited value and may not be cost effective. Laryngoscope, 2012 [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: Planned neck dissection following chemoradiation (CR) has been advocated in patients with head and neck squamous cell cancer (HNSCC) with advanced nodal disease and a clinical complete response to CR because of the potential for residual occult nodal disease. The utility of positron-emission tomography/computed tomography (PET-CT) in identifying occult nodal disease in this scenario is controversial. Methods: The medical records of all patients treated with CR for advanced HNSCC with N2 or N3 disease from December 2003 to June 2007 were reviewed. Patients with a complete clinical response were included if PET-CT performed 8 to 11 weeks after CR showed no distant disease and they underwent planned neck dissection. Results: Thirty-two patients met study criteria. PET-CT was positive for residual nodal disease in 20 patients (63%). Pathology revealed carcinoma in 10 patients (31%): six of 20 patients with positive PET-CT scans (30%) and four of 12 patients with negative PET-CT scans (33%). The sensitivity and specificity of PET-CT was 60% and 36%. Regional recurrence developed in two patients (6%) who were not successfully salvaged. Conclusions: PET-CT performed 8 to 11 weeks after CR does not reliably predict the need for planned post-treatment neck dissection in patients with a complete clinical response following CR. Regional recurrence rates are comparable to those reported for patients observed with PET-CT, suggesting no advantage for planned neck dissection, and salvage rates were poor. These data suggest that delaying the timing of PET-CT, with surgery reserved for positive findings, is a reasonable alternative to planned neck dissection to avoid unnecessary surgery. Laryngoscope, 2009 [ABSTRACT FROM AUTHOR]