Importance of combined use of preoperative 18F-FDG PET/CT imaging and intraoperative 18F-FDG handheld gamma probe detection in recurrent papillary thyroid cancer.

Radio-guided surgery using an intra-operative positron emission tomography (PET) probe in recurrent thyroid cancer (RTC) can be a useful method for tumor localization, verification of complete excision and to decrease operation time. We describe a case of RTC whose serum thyroglobulin (Tg) level was 5.6ng/mL. Preoperative fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) revealed two focal abnormalities in the anterior tracheal and right upper mediastinal regions and a handheld gamma probe was used intraoperatively to identify the hot areas seen on PET scan. Postoperative 18F-FDG PET/CT imaging after tumor excision was normal. This case shows that recurrent tumor can be localized correctly using 18F-FDG PET/CT and a surgical gamma probe.

The role of 68Ga-DOTA-TATE PET/CT scanning in the evaluation of patients with multiple myeloma: preliminary results.

OBJECTIVE: In this observational pilot study, we aimed to evaluate the role of gallium-68-labelled DOTA-TATE (Ga-TATE) PET/computed tomography (CT) scanning in patients with multiple myeloma (MM), considering previous promising results obtained from conventional somatostatin receptor scintigraphy with In pentetreotide. MATERIALS AND METHODS: Twenty-one patients with a diagnosis of MM were prospectively included in this study: eight patients were referred for initial staging and 13 patients for restaging purpose. Both fluorine-18 fluorodeoxyglucose (F-FDG) and TATE PET/CT scanning were performed in all patients. RESULTS: All patients had one or more PET-positive lesion on either F-FDG or TATE scans. Six patients had an additional diffusely increased bone marrow activity on F-FDG scans, five of whom also had a concordant bone marrow appearance on TATE scans. Each PET set (either F-FDG or TATE) was positive in 19 patients. There was a discordant result in four (19%) patients between F-FDG and TATE scans. F-FDG scans showed 112 lesions (86 TATE-positive; 26 TATE-negative) in 19 patients, whereas TATE scans showed 108 lesions (86 F-FDG-positive; 22 F-FDG-negative) in 19 patients. No significant difference was found between the two modalities in terms of lesion numbers detected (P=0.67). However, the presence of diffuse bone marrow uptake of TATE seems to be a predicting factor for the overall survival (P=0.033, hazard ratio: 15.2 and 95% confidence interval: 1.2-185.5). CONCLUSION: TATE PET/CT seems to be an alternative imaging modality and may play a complementary role in MM management, at least by providing a different pathobiological insight into the disease.

Compatibility of MRI and FDG-PET findings with histopathological results in patients with focal cortical dysplasia.

PURPOSE: The present study aimed to determine if the specific characteristics of fluorodeoxyglucose-positron emission tomography (FDG-PET) analyses of the FCD subgroups were compatible with the magnetic resonance imaging (MRI) and clinical findings of the patients in these subgroups. METHODS: This study included 71 patients who had a presurgical evaluation workup performed due to drug-resistant seizures, who underwent epilepsy surgery, and who were histopathologically diagnosed with FCD. Relationships involving MRI and FDG-PET findings and clinical data from pathological subgroups and patients were assessed. RESULTS: According to the International League Against Epilepsy (ILAE) classifications of FCD, 28 of the patients were type I and 43 were type II. FCD was visible on the MRI scans of 53 patients, and a majority of this group was classified as type II FCD (n=34). Of these 53 patients, FCD was located in the temporal area of 21 patients, the extratemporal area of 29 patients. Of the patients who exhibited FDG-PET hypometabolism (PET-positive), 23 were classified as temporal, 17 as frontal, 11 showed involvement of the posterior cortex. The age of seizure onset was younger in PET-positive patients (p=0.032), and histopathological analyses revealed that 23 patients had type I FCD and 30 patients had type II FCD. CONCLUSION: PET scans reveal a lesion by showing hypometabolism in patients who have refractory epilepsy and an early age of onset with FCD. The lesions of MRI-negative/PET-positive FCD patients tend to be localized in the temporal lobe and that FCD may be localized in the frontal lobe of MRI-negative/PET-negative patients. However, the histopathological examinations of MRI-positive/PET-positive, MRI-negative/PET-positive, and MRI-negative/PET-negative patients did not exhibit a particular histopathological subtype.

Laryngeal squamous cell cancer with late presentation of isolated liver metastasis on fluorodeoxyglucose positron emission tomography-computed tomography.

Laryngeal cancer is the second most common type of head and neck malignancy, representing approximately 45% of all head and neck cancers. Hematogenous spread to the liver rarely occurs without evidence of pulmonary and bone disease. We report a patient who had been treated 7 years earlier for laryngeal squamous cell cancer and who had isolated liver metastasis on fluorodeoxy D-glucose positron emission tomography-computed tomography.

The role of FDG PET/CT in detection of distant metastasis in theinitial staging of breast cancer.

BACKGROUND/AIM: We aimed to evaluate the role of FDG PET/CT in the detection of extraaxillary regional nodal/distant metastasis in breast cancer patients and to assess the value of FDG PET/CT for detecting distant metastases in patient subgroups. MATERIALS AND METHODS: A total of 254 patients with breast cancer (248 female, 6 male) who underwent PET/CT for initial staging were enrolled. Patients were divided into four groups: Group 1 consisted of 154 patients diagnosed by tru-cut/core/FNAB, Group 2 comprised 32 patients diagnosed by excisional biopsy, Group 3 included 62 patients who had mastectomy-axillary lymph node dissection, and Group 4 consisted of 6 patients who had axillary lymph node metastasis diagnosed by excisional biopsy. RESULTS: PET/CT detected distant metastasis in 76 of the 254 patients. Of these patients, 21.7% had bone/bone marrow metastasis, 7.1% had lung metastasis, 13% had mediastinal lymph node metastasis, 4.8% had liver metastasis, 9.8% had other organ/system metastasis, and 6% had other lymphadenopathies. According to T staging, the percentages of distant metastasis were as follows: 13.6% of the 66 T1 stage patients, 35.7% of the 129 T2 stage patients, 40% of the 20 T3 stage patients, and 33.3% of the 39 T4 stage patients. CONCLUSION: FDG-PET/CT led to a change in the stage of disease and the treatment approach in newly diagnosed breast cancer patients due to its superiority in detecting extraaxillary regional lymph node metastases and distant metastases.

Depiction of ventriculoperitoneal shunt obstruction with single-photon emission computed tomography/computed tomography.

An 83-year-old male patient with ventriculoperitoneal shunt underwent radionuclide shunt study using single-photon emission computed tomography/computed tomography (SPECT/CT) to evaluate the shunt patency. The planar images showed activity at the cranial region and spinal canal but no significant activity at the peritoneal cavity. However, SPECT/CT images clearly demonstrated accumulation of activity at the superior part of bifurcation level with no activity at the distal end of shunt as well as no spilling of radiotracer into the peritoneal cavity indicating shunt obstruction. SPECT/CT makes the interpretation of radionuclide shunt study more accurate and easier as compared with traditional planar images.

Do 18F-FDG PET/CT findings have a relationship with histopathological and immunohistochemical factors of breast cancer in men?

PURPOSE: We aimed to investigate the relationship between histopathological and immunohistochemical features of male breast cancer (MBC) and comprehensive fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) parameters. METHODS: Fifteen male patients with newly diagnosed breast cancer who underwent F-FDG PET/CT were included in the study. Maximum and average standardized uptake value (SUVmax and SUVavg), metabolic total volume, and total lesion glycolysis (TLG) were compared with the histopathological and immunohistochemical findings of patients. In addition, metabolic tumor-node-metastases (TNM) staging was performed following the determination of metastatic axillary lymph nodes and tumor size by F-FDG PET/CT and verified by histopathological evaluation. RESULTS: There were no significant differences between all groups classified on the basis of histopathological and immunohistochemical parameters for SUVmax, SUVavg, TLG, and metabolic total volume. The only difference was found in patients with distant metastases and stage IV. SUVmax, SUVavg, and TLG were higher in patients with distant metastases compared with patients without distant metastases (P: 0.005, 0.011, and 0.042, respectively). Strong correlations were found between metabolic TNM staging and histopathological TNM staging (for T stage; r: 0.590, P: 0.021, N stage; r: 0.694, P: 0.002, TNM stage; r: 0.835, P: 0.002). In addition, no differences were found with any metabolic F-FDG PET/CT parameters in survival. CONCLUSION: Although no correlation was found between metabolic parameters and groups categorized on the basis of histopathological or immunohistochemical features, F-FDG PET/CT is a reliable imaging modality to determine tumor size, axillary lymph node involvement, and metabolic TNM staging of MBC. In addition, none of those metabolic F-FDG PET/CT parameters predicted survival in MBC.

Diagnostic value of F-18 FDG PET/CT in patients with spondylodiscitis: Is dual time point imaging time worthy?

PURPOSE: In this retrospective study, we aimed to investigate the value of FDG-PET/CT in the diagnosis of spondylodiscitis (SD), the significance of dual time point imaging (DTPI) for SD diagnosis and the worth of SUVmax data for distinguishing tuberculous vs. non-tuberculous SD. MATERIALS AND METHODS: 32 patients with suspected SD were scanned with FDG-PET/CT. For quantitative analysis maximum standardized uptake value (SUVmax) of the lesion area was measured. Nineteen patients had DTPI of FDG-PET/CT. The final diagnoses were achieved by histopathological, microbiological, and clinical results. RESULTS: Specific pathogens were isolated in 21 patients; other patients were accepted as nonspecific bacterial SD. In all patients, FDG-PET/CT results were compatible with SD diagnosis. The SUVmax data for tuberculous and non-tuberculous SD and DTPI results were statistically insignificant. CONCLUSION: FDG-PET/CT is a successful modality for SD diagnosis; additionally, DTPI protocol for FDG-PET/CT in SD diagnosis and SUVmax data for differentiation between non-tbc SD and tbc SD are useless.

Comparison of (18)F-fluorodeoxyglucose PET/CT findings with vascular endothelial growth factors and receptors in colorectal cancer.

The purpose of this study was to evaluate the association of (18)F-fluorodeoxyglucose (FDG)-PET/CT findings with the vascular endothelial growth factor (VEGF) family and its receptor (VEGFR) levels in metastatic and nonmetastatic colorectal cancer (CRC). Fluorine-18 FDG-PET/CT scans were performed for initial staging and restaging of patients with CRC. FDG-PET/CT findings of tumor (such as the presence of a primary tumor, the lymphatic or distance metastases, and the maximum standardized uptake value (SUVmax) of the primary tumor), serum VEGF A-C-D-E levels, and serum VEGF receptor 1-2-3 levels were analyzed. A total of 63 patients were included into the study (35 males, mean age 61.3 ± 11.9 years). Patients were divided into two groups, based on positive and negative PET/CT findings. Patients were also categorized according to the presence of metastasis. All evaluated parameters were significantly higher in the PET/CT-positive group than the PET/CT-negative group (p < 0.001). All those parameters were also positively correlated with each other. The highest correlation for SUVmax of primary tumor was found with VEGFR-3 (p < 0.001, r = 0.665). Patients with metastases had high levels of VEGF-D, VEGF-A, VEGF-C, VEGF-E, and VEGFR-3 than those without metastases. These parameters had better specificity and sensitivity values than the SUVmax of the primary tumor for detection of metastases. However, VEGF-D was the best indicator of metastasis in all of those parameters (VEGF-D vs SUVmax; sensitivity 100 vs 100 %; specificity 76 vs 76 %; AUC 0.903 vs 0.835; p < 0.001, respectively). Vascular endothelial growth factor family and its receptors were significantly higher in metastatic CRC patients. VEGF-D was the best indicator of metastasis than all VEGF family, VEGFR-3, and primary tumor SUVmax. VEGF family (A-C-D-E) and VEGFR-3 may help to determine the prognosis and management of CRC.

Evaluation of PSMA PET/CT imaging using a 68Ga-HBED-CC ligand in patients with prostate cancer and the value of early pelvic imaging.

PURPOSE: The aim of the study was to evaluate the diagnostic value of the prostate-specific membrane antigen (PSMA) ligand (68)Ga-HBED-CC (PSMA PET/CT) in patients with prostate cancer and evaluate the value of early imaging of the pelvis. MATERIALS AND METHODS: The files of 28 patients were retrospectively evaluated. All patients had a histopatological confirmation of prostate cancer. PSMA PET/CT images were obtained at 5 and 60 min after injection from all patients. RESULTS: Intense pathologic radiotracer uptake was observed in 23 patients (77%) at the site of primary tumour. Lymph node metastases were detected in 10 patients (36%) and bone metastases were detected in seven patients (25%). Bone scan (n=25) results revealed metastatic bone lesions in four patients, equivocal results in nine patients and normal results in 12 patients. PSMA PET/CT confirmed bone metastases in all four patients. Pathologic radiotracer uptake in PSMA PET/CT scans was observed only in one patient among those who had equivocal bone scans. PSMA PET/CT showed additional bone lesions in two patients who had a normal bone scan. When we compared early and late pelvic images we found no difference in the number of lesions detected. The maximum standardized uptake value (SUV(max)) for primary tumour, lymph nodes and bone metastases was significantly higher in late images. CONCLUSION: PSMA PET/CT imaging seems to be a valuable imaging modality for evaluation of primary prostate cancer and it seems to have potential for the detection of lymph node and bone metastases. Early images 5 min p.i. can help to better distinguish between urinary bladder (before tracer accumulation occurs) and tumour lesions.

Contribution of FDG-PET in epilepsy surgery: consistency and postoperative results compared with magnetic resonance imaging and electroencephalography.

AIM: Surgery is a treatment option for medically intractable epilepsy patients. Abnormalities in regional cerebral glucose metabolism, as identified by 18-fluorodeoxyglucose positron emission tomography (FDG-PET) have predictive prognostic value in evaluating the outcome of epilepsy surgery. This study investigated the efficacy of FDG-PET for delineation of the epileptogenic zone (EZ) by comparing its consistency with other diagnostic tools and surgical outcome. MATERIAL AND METHODS: We analyzed the results of 121 consecutive patients evaluated for epilepsy surgery. FDG-PET results were crosschecked with magnetic resonance imaging (MRI) and electroencephalography (EEG) results, as well as postoperative outcome and pathology. RESULTS: FDG-PET findings of 75 patients (62 %) were concordant with MRI (Mc-Nemar-χ2 test p=0.024, Kappa=0.22). Further, the PET findings were consistent with EEG, and was statistically significant, according to Post-hoc test, in temporal epilepsy (TLE) group (χ2=8.21 P=0.04). Both investigations revealed localizing information in 56 (46.2%) patients. Twenty-six (72.2%) MRI-negative patients had hypometabolism on PET. The pathology of the 10 PET-negative patients was 5 cases of mesial temporal sclerosis, 2 cortical dysplasia, 2 gliosis and one tumor. Seven (70%) of these patients' lesions originated from the temporal lobe. FDG-PET had correctly predicted the EZ in 37 (86%) of 43 patients who underwent surgery. CONCLUSION: FDG-PET results may not be strongly associated with EZ but represent an additional tool in delineation of EZ during the noninvasive phase of presurgical evaluation.

The value of FDG-PET/CT by using 3-dimensional stereotactic surface projection software analysis in the differential diagnosis of dementia.

BACKGROUND/AIM: To retrospectively reevaluate brain fluor-18-fluorodeoxyglucose positron emission tomography (FDG-PET) imaging studies with 3-dimensional stereotactic surface projection (NEUROSTAT) software in order to detect changes in regional brain metabolism and to find out its contribution to the final diagnosis. MATERIALS AND METHODS: A total of 48 cases were included in this study. According to clinical evaluation and neuropsychometric test results, there were 17 (35%) patients with probable Alzheimer disease (AD), 17 (35%) patients with probable frontotemporal dementia (FTD), and 14 (30%) patients with undefined advanced dementia. Brain FDG-PET imaging studies were interpreted visually and also using 3-dimensional stereotactic surface projection. RESULTS: Clinic and PET findings were consistent in 20 patients and inconsistent in 14 patients. When consensus diagnosis was taken as the reference, the sensitivity, specificity, accuracy, and positive and negative predictive values of FDG-PET imaging were 93%, 85%, 90%, 90%, and 89% respectively, for AD diagnosis. The same values were 85%, 93%, 90%, 89%, and 90%, respectively, for FTD definition. CONCLUSION: Using automatized programs that enable quantitative evaluation of regional brain glucose metabolism, in addition to visual evaluation, may increase diagnostic efficiency, as well as minimize interobserver and/or intercenter variability.

FDG PET-CT Finding in Bilateral Renal and Bone Involvement of Diffuse Large B-Cell Lymphoma.

Thirty-six year old male patient with pathological fracture of the left tibia underwent intramedullary and soft tissue curettage. The histopathological examination revealed diffuse large B cell lymphoma. The patient underwent F18-FDG PET-CT scanning for initial staging. FDG PET-CT scan revealed hypermetabolic lesions at the left tibia and in bilateral kidneys. After the systemic chemotherapy and local radiotherapy to the tibia, repeated FDG PET/CT scan showed improvement of the previous hypermetabolic lesions, suggesting good response to therapy. Bone and renal involvement is an uncommon variant of diffuse large B-cell lymphoma and FDG PET-CT is an useful whole body imaging modality in these cases.

The role of FDG-PET/CT in differentiated thyroid cancer patients with negative iodine-131 whole-body scan and elevated anti-Tg level.

AIM: In the follow-up of differentiated thyroid cancer (DTC) after a successful total-near total thyroidectomy and I-131 ablation therapy, anti-thyroglobulin antibodies (anti-Tg) may be persistently or progressively increased in the patients with an undetectable serum thyroglobulin (Tg) level. In these cases, further investigation was performed to search for recurrence/metastases. The aim of our study was clarifying the role of FDG-PET/CT in detecting recurrence/metastasis in patients with DTC with negative serum Tg and elevated anti-Tg level. MATERIALS AND METHODS: A total of 40 patients (32 female, 8 male; mean age: 43.15 years (22-65); mean age at diagnosis: 39.08 (16-64)) with DTC who had undetectable serum Tg and elevated anti-Tg level after a successful initial therapy were included in the study. All of the patients had serum anti-Tg of >40 IU/ml and underwent FDG-PET/CT to search for recurrence/metastasis. RESULTS: Twenty patients (50 %) had recurrence/metastasis on FDG-PET/CT while the other 20 had no pathologic findings. Of the 20 patients who had positive FDG-PET/CT, 12 had a histopathological final diagnosis of which 11 were true positive (TP) and 1 was false positive (FP). On the other hand, 16 of the 40 patients had a histopathological final diagnosis of which 11/16 had TP, 1/16 FP, 3/16 false negative (FN) and 1/16 true negative (TN) findings by PET/CT. The final diagnosis was made by clinical follow-up in the remaining 24 patients. Of these, 8 patients were PET positive, and in 1 (12.5 %) of 8 patients a decrease in serum anti-Tg level, in 2 (25 %) patients a saw-toothed pattern and in 5 (62.5 %) a progressive increase in the serum anti-Tg level were noted during the follow-up. Of the 16 of 24 patients who were diagnosed by clinical follow-up, in 8 a (50 %) decrease in serum anti-Tg level, in 6 (37.5 %) a saw-toothed pattern, and in 2 (12.5 %) a progressively increased anti-Tg level was seen. Of the 40 patients, 14 (35 %) had a diagnosis of recurrence/metastasis finally, with PET/CT detecting 11 (78.6 %) of them. CONCLUSION: The value of a persistently or progressively increased serum anti-Tg level in the follow-up of DTC in the prediction of recurrence/metastasis is controversial. However, it is reported that FDG-PET can be useful in the detection of recurrence/metastasis. We conclude from the available data that PET/CT can be effectively used in the detection of recurrence/metastasis in the follow-up of patients with DTC and negative serum Tg and a persistently/progressively increased anti-Tg level. Besides, one half of the patients were FDG negative, meaning that further studies are needed to assess the prognostic-clinical value of PET negativity.

A rare case of solitary subcutaneous scalp metastasis from follicular thyroid carcinoma revealed with positron emission tomography/computed tomography: a case report and review.

Differentiated thyroid cancer frequently metastasizes to regional cervical lymph nodes and in advanced cases metastases can be seen in the lungs and skeleton. Metastases to the skin or subcutaneous tissue are rare. Here we present a 49-year-old female patient with solitary scalp metastasis from follicular thyroid carcinoma FTC which was revealed with positron emission tomography (PET)/computed tomography (CT) imaging. PET showed flourodeoxiglucose avid lesion in the left vertex scalp. Scalp lesion was removed totally and histopathological examination revealed well-differentiated thyroid cancer metastasis.

Detection of Hodgkin Transformation in a Case of Chronic Lymphocytic Leukemia by PET/CT.

Richter's transformation (RT) represents the development of high grade lymphoma, most commonly diffuse large B-cell lymphoma, in patients with chronic lymphocytic leukemia or small lymphocytic lymphoma (CLL/SLL). CLL/SLL may convert also to Hodgkin's lymphoma, the so-called Hodgkin's variant of Richter transformation. Histopathological proof is needed to confirm a definitive diagnosis. Patients with RT generally have a poor prognosis, with prompt recognition optimise clinical management. Whole-body PET scan with 18F-FDG can be used for detection of RT of CLL/SLL. We describe the case of 64-year-old woman with CLL/SLL who developed Hodgkin lymphoma detected with PET/CT.