The relationship between 18F-FCH uptake intensity and cell content in parathyroid lesions.

PURPOSE: To investigate the relationship between cell content and histopathological features of parathyroid lesions and 18F-FCH uptake intensity on PET/CT images. METHODS: Patients with primary hyperparathyroidism (age > 18) who were referred to 18F-FCH PET/CT were involved. All patients underwent parathyroidectomy. Correlation of SUVmax with following factors were statistically analysed: serum PTH, Ca, P levels and histopathological parameters, total absolute amounts of chief cell, oxyphyllic cell and clear cell components calculated by the multiplication of the volume of the parathyroid lesion and the percentage of each type of cell content (called as Absolutechief, Absoluteoxyphyllic and Absoluteclear reflecting the total amount of each cell group). RESULTS: A total of 34 samples from 34 patients (6M, 28F, mean age: 53.32 ± 15.15, min: 14, max: 84) who had a positive 18F-FCH PET/CT localizing at least one parathyroid lesion were involved. In the whole study group, SUVmax was found to be correlated with the greatest diameter and volume of the lesion and Absolutechief (p = 0.004, p = 0.002 and p = 0.035, respectively). In the subgroup analysis of 28 samples with longest diameter > 1 cm, the correlation between SUVmax and Absolutechief remained significant (p = 0.036) and correlation between SUVmax and volume and longest diameter became stronger (p = 0.011 and p > 0.001, respectively). No correlation was found between SUVmax and Absoluteoxyphyllic or Absoluteclear. CONCLUSIONS: There might be a relationship between 18F-FCH uptake intensity and chief cell content in patients with parathyroid adenoma. Further studies with larger patient groups would be beneficial to support the data.

Negative Histopathological Prognostic Factors Affecting Morbidity in T1 Differentiated Thyroid Carcinoma.

Background: The aim was to evaluate: (i) if multifocality is a negative prognostic factor; and (ii) the association of diameter of the largest tumor, total tumor diameter, and the ratio of the largest tumor diameter to total tumor diameter (DR) with histopathological and clinical outcome parameters in T1 differentiated thyroid carcinoma (DTC). Materials and Methods: In 1014 T1N0/1Mx patients, correlation between multifocality, contralateral lobe involvement, capsular-vascular invasion, diameter of the largest tumor, total tumor diameter, DR, and follow-up results were investigated. Results: Persistent/recurrent disease and necessity for additional radioiodine treatment (RAIT) were more frequent in cases with multifocality and contralateral lobe involvement (p = 0.035, p = 0.015, p = 0.021, and p = 0.04). Persistence/recurrence, reoperation in the neck, and additional RAIT were more frequent in patients with the size of the largest tumor focus >1 cm (p = 0.024, p < 0.001, and p = 0.002) and N1 status (p < 0.001, p < 0.001, and p < 0.001). Mean total tumor diameter was higher in patients with capsular invasion, contralateral lobe, and lymph node involvement (p = 0.001, p = 0.003, and p = 0.013). Conclusion: Multifocality, contralateral lobe involvement, diameter of the largest tumor >1 cm, and N1 status are related with increased risk of disease persistence, recurrence, reoperation, and additional RAIT. Sum of diameter of all tumor foci are associated with capsular invasion.

Detectability of 18F-choline PET/MR in primary hyperparathyroidism.

PURPOSE: We aimed to evaluate the power of 18F-fluorocholine (FCH) positron emission tomography/magnetic resonance (PET/MR) imaging in unlocalized primary hyperparathyroidism. METHODS: Thirty-four patients were included. In 17/34 patients, PET/MR was performed immediately after a negative 18F-FCH PET/CT. Sensitivity, specificity, positive and negative predictive values were calculated for MR only (blinded to PET data) and PET only (blinded to MR data) findings. RESULTS: 18F-FCH PET/MR was positive in 26/34 (76%) patients. PET/MR was also positive in 12/17 (71%) patients with a negative PET/CT. Among 11/34 (32%) patients where 18F-FCH PET-only and MR-only results were discordant, MR was false positive in 7/11 patients (3/7 of the lesions were not 18F-FCH avid and in 4/7 of them PET and MRI pointed different locations. Postoperative histopathology revealed that 18F-FCH-positive ones were true positives). Sensitivity, specificity, PPV, NPV and accuracy of neck MR evaluated blinded to PET data were 80%, 50%, 70%, 64% and 68%, respectively, and all were calculated as 100% for PET/MR. CONCLUSION: 18F-FCH PET/MR is very effective in preoperative localization of parathyroid adenomas even if 18F-FCH PET/CT is negative. Neck MR alone is insufficient in detecting parathyroid adenomas but PET/MR combination helps in precise localisation.

Role of Thyroglobulin Doubling Time in Differentiated Thyroid Cancer and Its Relationship with Demographic-Histopathologic Risk Factors and 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Parameters.

Background: Aim of this study was to investigate the relationship between thyroglobulin doubling time (TgDT) and basal risk factors and metabolic parameters derived from 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in differentiated thyroid cancer (DTC). Materials and Methods: An analysis of 95 DTC patients who had rising serum thyroglobulin (Tg) levels under levothyroxine (LT4) suppression after radioiodine therapy was made. TgDT was calculated for 28/95 patients. The relationship between TgDT and basal demographic and histopathologic risk factors, preablative Tg, and antithyroglobulin antibody (ATg) levels and metabolic parameters was analyzed. Results: In 28 patients (15M, 13F, mean age: 52.6 ± 17.6) that TgDT could be calculated, 18F-FDG PET/CT was positive in 12 patients. Median TgDT was lower in 18F-FDG PET/CT positive patients compared to the negative cases (p < 0.05). Patients with skeletal metastasis or local recurrence had a shorter DT compared to the patients with lung metastasis. TgDT was correlated with peak standardized uptake value (SUVpeak) (p < 0.05). Maximum standardized uptake value (SUVmax) was correlated with tumor size (p < 0.05) and mean standardized uptake value (SUVmean) with tumor size and vascular invasion (p < 0.05). Median SUVmax and SUVmean were higher in follicular cancer or poor histological variants of papillary DTC compared to papillary cancer classical variant patients Conclusion: TgDT may be predictive of a positive 18F-FDG PET/CT in DTC. Skeletal metastasis and local recurrence are related to shorter TgDT. Greater tumor size, vascular invasion, and follicular cancer or poor variants of papillary carcinoma are related with higher SUVmax and SUVmean. Larger scale studies are needed to confirm results and to calculate a possible cutoff of TgDT for a positive 18F-FDG PET/CT study.

Incidental 18F-Fluorocholine Uptake in an Esophageal Diverticulum: 18F-FCH in an Esophageal Diverticulum.

F-fluorocholine has recently emerged as a very sensitive agent for seeking parathyroid adenomas. We represent a case with esophageal diverticulum incidentally detected on F-fuorocholine PET/CT, which should be kept in mind as a reason of false positivity in primary hyperparathyroidism.

Correlation of minimum apparent diffusion coefficient with maximum standardized uptake on fluorodeoxyglucose PET-CT in patients with rectal adenocarcinoma.

PURPOSE: The aim of this study was to retrospectively assess the correlation between minimum apparent diffusion coefficient (ADCmin) values obtained from diffusion-weighted magnetic resonance imaging (MRI) and maximum standardized uptake values (SUVmax) obtained from positron emission tomography-computed tomography (PET-CT) in rectal cancer. MATERIALS AND METHODS: Forty-one patients with pathologically confirmed rectal adenocarcinoma were included in this study. For preoperative staging, PET-CT and pelvic MRI with diffusion-weighted imaging were performed within one week (mean time interval, 3±1 day). For ADC measurements, the region of interest (ROI) was manually drawn along the border of each hyperintense tumor on b=1000 s/mm2 images. After repeating this procedure on each consecutive tumor-containing slice to cover the entire tumoral area, ROIs were copied to ADC maps. ADCmin was determined as the lowest ADC value among all ROIs in each tumor. For SUVmax measurements, whole-body images were assessed visually on transaxial, sagittal, and coronal images. ROIs were determined from the lesions observed on each slice, and SUVmax values were calculated automatically. The mean values of ADCmin and SUVmax were compared using Spearman's test. RESULTS: The mean ADCmin was 0.62±0.19×10-3 mm2/s (range, 0.368-1.227×10-3 mm2/s), the mean SUVmax was 20.07±9.3 (range, 4.3-49.5). A significant negative correlation was found between ADCmin and SUVmax (r=-0.347; P = 0.026). CONCLUSION: There was a significant negative correlation between the ADCmin and SUVmax values in rectal adenocarcinomas.

Correlation of 18F-FDG PET/CT findings with histopathological results in differentiated thyroid cancer patients who have increased thyroglobulin or antithyroglobulin antibody levels and negative 131I whole-body scan results.

AIM: This study aimed to investigate the correlation of 18F-FDG PET/CT findings with histopathological results in defining the recurrence of the disease in patients with differentiated thyroid cancer (DTC) who have increased thyroglobuline (Tg) or anti-Tg antibody (TgAb) levels and negative 131I whole-body scan (WBS) result. PATIENTS AND METHODS: A total of 59 patients with DTC (44 women, 15 men; mean [SD] age, 48.2 [22.6] years) were included in the study. All of the patients had previous papillary thyroid cancer, and all of them had undergone radioiodine ablation after a total or near-total thyroidectomy. After radioiodine ablation, patients were followed up for approximately 2.5 years. In the follow-up, the patients with negative 131I-WBS results and increased Tg or TgAb levels under thyroid-stimulating hormone-stimulated conditions underwent an 18F-FDG PET/CT scan to determine any recurrence of disease. There were negative or uncertain findings in the neck ultrasonography and/or thorax CT in most of the patients. The 18F-FDG PET/CT findings were compared with the histopathological results in all patients. RESULTS: Although 49 patients had increased Tg levels, the remaining 10 patients had increased TgAb levels. In patients with high Tg levels, 18F-FDG PET/CT scan results were negative in 10 and positive in 39 patients. In this patient group, 18F-FDG PET/CT findings were true positive, true negative, false positive, and false negative in 32, 3, 7, and 7 patients, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT in this group were calculated as 82%, 30%, 80%, 30%, and 71%, separately. In the receiver operating characteristic analysis, a 4.5 cutoff SUV(max) was calculated with 75% sensitivity and 70% specificity for predicting disease recurrence. Cutoff Tg level was calculated as 20.7 ng/mL with 75% sensitivity and 55% specificity. In 10 patients with high TgAb levels, 18F-FDG PET/CT was true positive, true negative and false positive in 6, 2, and 2 patients, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 18F-FDG PET/CT in this patient group were calculated as 100%, 50%, 75%, 100%, and 80%, respectively. CONCLUSIONS: 18F-FDG PET/CT may be a useful imaging modality in defining recurrence of the disease in patients with DTC who have increased Tg or TgAb levels, negative 131I-WBS results, and negative or suspicious neck ultrasonography and/or thorax CT results. Although 18F-FDG PET/CT seems to be a more sensitive method in patients with increased TgAb levels, the number of patients is not enough to make a substantiated comment.

Efficacy of adding high-dose In-111 octreotide therapy during Sandostatin treatment in patients with disseminated neuroendocrine tumors: clinical results of 14 patients.

PURPOSE: This study aimed to assess the outcome of high-dose In-111 octreotide treatment and efficacy of long-acting Sandostatin LAR in patients with disseminated neuroendocrine tumors. MATERIALS AND METHODS: A total of 14 patients (mean age 51.8 ± 13.2 years; 10 female, 4 male) receiving high-dose In-111 octreotide in our centre for the treatment of neuroendocrine tumors were included in the study. Monthly treatment with long-acting somatostatin analogue [Sandostatin long-acting release (Novartis Pharmaceuticals)] was continued in nine cases. RESULTS: During a 3-year period, a total of 45 courses of high-dose In-111 octreotide treatment were delivered to 14 patients. In seven patients receiving an average of four treatment courses (6 carcinoid tumors, 1 thymoma, patients: 2, 4, 5, 11-14) stable disease was achieved (50%). In two patients with carcinoid tumors (patients 1 and 3) who received four treatment courses, partial response was observed (14%). Five patients (36%; 4 NET, 1 gastrinoma; patients 6-10) died due to progressive disease following on average two treatment courses. On average, deaths occurred 2 months after the last treatment dose. No complete responses were seen. Partial response was achieved in two of the nine patients receiving Sandostatin LAR, while four had stable disease. Both treatments were associated with acceptable tolerability. CONCLUSIONS: High-dose In-111 octreotide can be safely administered in conjunction with somatostatin analogue in patients with disseminated NET and this treatment may help to stabilize the disease.

Ocular Involvement in Mantle Cell Lymphoma Detected by F 18 FDG PET/CT.

UNLABELLED: Mantle Cell Lymphoma (MCL) is an uncommon but aggressive form of non-Hodgkin's lymphoma. The extranodal involvement is not unusual especially in bone marrow, spleen, gastrointestinal tract and Waldeyer's ring. Ocular involvement is very exceptional and the most commonly affected site is the orbit (90%), followed by the lacrimal gland (50%) and the eyelids (50%). Today, PET/CT is widely used in non-Hodgkin's lenfoma especially in staging and evaluation of treatment response. Authors report MCL with ocular involvement that was detected on PET/CT scan. CONFLICT OF INTEREST: None declared.

Is thyroglobulin the stronger indicator for progressive disease than the other conventional factors in same age patient groups with differentiated thyroid cancer?

AIM: To determine the thyroglobulin cut-off value as an indicator for progressive disease and to research relationships between sex, histological type, extra-capsular invasion and progressive disease in differentiated thyroid cancer. METHODS: Four hundred and eight patients were evaluated retrospectively. One hundred and fifty-eight patients (group 1) treated for progressive disease and 166 patients (group 2) that were ablated for thyroid remnant were included in our study. Sex, age, histological type, presence of extra-capsular invasion at the diagnosis and L-thyroxine off thyroglobulin values (6-12 months after the ablation) were obtained. Data were analysed by statistical methods. RESULTS: There was no statistically significant difference for ages (group 1, 45.3+/-16.1 years; group 2, 47+/-12 years, P>0.05). The chi-squared test revealed statistically significant differences for histological type (P>0.05) and extra-capsular invasion (P<0.001) but not for sex (P>0.05). Feasible cut-off level, sensitivity and specificity were found as a 10 ng.ml thyroglobulin value, 79% and 97%, respectively. However, sensitivity and specificity were 80%, 92% for 5 ng.ml and 82% for 2 ng.ml thyroglobulin levels. Multivariate analysis showed that a 10 ng.ml thyroglobulin cut-off value and extra-capsular invasion were independent prognostic factors. CONCLUSION: Increased thyroglobulin level, extra-capsular invasion and follicular type were poor prognostic factors but sex was not, whereas only extra-capsular invasion and increased thyroglobulin level were independent prognostic indicators for our groups. A 10 ng.ml thyroglobulin level was a feasible cut-off and seemed to be a stronger factor than other indicators to predict progressive disease.

Assessment of bone density differences between conventional and bone-condensing techniques using dual energy x-ray absorptiometry and radiography.

OBJECTIVES: We used dual energy x-ray absorptiometry (DEXA) and periapical radiography to assess bone density differences after conventional and bone-condensing dental implant techniques. STUDY DESIGN: Single-tooth dental implants were placed by both conventional and bone-condensing techniques in 14 patients with bilateral missing teeth. Dual energy x-ray absorptiometry was used to calculate bone mineral density (BMD) and bone mineral content (BMC) before and 6 and 12 months after implant placement. Furthermore, photodensitometry of periapical radiographs was also assessed. RESULTS: The success rate was 92.9% for the conventional technique and 71.5% for the bone-condensing technique. The BMD was observed to be significantly higher 6 and 12 months after implant placement. The BMC and photodensitometry were significantly increased 6 months after implant placement but showed no further after 12 months. CONCLUSIONS: There were no significant differences in BMD, BMC, and photodensitometry between the two implant placement techniques. However, success rate of the conventional technique was greater than the bone-condensing technique, which may be the result of trabecular fracture associated with the bone-condensing.

Lymphoscintigraphy in detection of the regional lymph node involvement in gastric cancer.

INTRODUCTION: Involvement of regional lymph node is a critical sign in prognosis of gastric cancer. Radiological techniques are commonly used to evaluate the extension of gastric cancer. But their sensitivity and specificity are low especially in the early stage. Our aim was to assess the value of gastric lymphoscintigraphy in identifying regional lymph node involvement in patients with gastric cancer, as compared to the abdominal ultrasonography, computed tomography and postoperative histopathological evaluation. PATIENTS AND METHODS: 50 patients (12 females) with a median age of 61 years (range, 35-73 years) were included in the study. Pre-operative staging in all cases included upper gastrointestinal endoscopy and biopsy, followed by ultrasound, computed tomography and lymphoscintigraphy. 148 MBq Technetium-99m lymphoscint was injected around the tumour during endoscopy and immediately after injection, anterior, lateral and posterior images were taken in 5-min intervals using a gamma camera. Findings were compared to the findings of other tests. The sensitivity, specificity, positive predictive value, and negative predictive value of each test were calculated and compared. RESULTS: Histologically, 68% of cases (34/50) had metastasis in regional lymph nodes and all cases were accurately diagnosed by lymphoscintigraphy. Lymphoscintigraphy was significantly more sensitive for detecting lymph node involvement (P < 0.01). Both abdominal ultrasonography and CT had very low sensitivity in identifying lymph nodes. CONCLUSIONS: Lymphoscintigraphy is a promising test in the identification of regional lymph nodes pre-operatively in patients with gastric cancer. It might help the surgeon to plan the extent of dissection before surgery which may decrease postoperative complications related to unnecessary extensive lymph node dissection.

Intraoperative lymphatic mapping and sentinel lymph node biopsy using radioactive tracer in gastric cancer.

BACKGROUND: Gastric cancer continues to be a significant health problem around the world. Surgical resection with a lymph node dissection remains the only potentially curative treatment with gastric cancer. Determination of the extent of lymph node dissection required on the basis of actual node involvement in patients with gastric cancer is important as less extensive dissection may reduce postoperative morbidity and mortality rates. The current study examines the feasibility and reliability of sentinel lymph node biopsy in gastric cancer. METHODS: A total of 32 patients who underwent gastrectomy with extended lymphadenectomy were enrolled in this study. A total volume of 148 MBq (2 mL) technetium-99m-radiolabeled, filtered sulphur colloid solution was injected into the primary lesion under gastroscopy 2 hours before the operation. Lymph nodes were examined as soon as possible by a hand-held gamma probe during the operation, without significant manipulation of the stomach or greater omentum. A sentinel lymph node (SLN) was defined by a level of radioactivity 10 times higher than the background. RESULTS: Thirty-one of 32 patients had successful SLN biopsy, with a success rate of 97%. The sensitivity, specificity, positive predictive value, and negative predictive value of SLN biopsy were 100%, 95%, 90%, and 100%, respectively. CONCLUSIONS: SLN biopsy using gamma probe in gastric cancer is a feasible procedure with high sensitivity and accuracy. This technique may be of a great benefit to surgeons in planning the extend of lymph node dissection in gastric cancer.