Unusual Presence of Synchronous Primary Ovarian and Thyroid Extranodal Non-Hodgkin Lymphoma Without Lymph Node Involvement.

ABSTRACT: Extranodal lymphomas without lymph node involvement are rarely observed and create diagnostic challenges. We present the case of a 33-year-old woman who was admitted with abdominal swelling. Ultrasonography findings suggested bilateral ovarian masses. 18 F-FDG PET/CT revealed intense uptake on the bilateral pelvic mass and thyroid gland. Following excisional surgery and thyroid fine-needle aspiration biopsy, the patient was diagnosed with diffuse large B-cell lymphoma. This case is exceptionally rare, as it presents 2 synchronous extranodal involvements in the ovaries and the thyroid gland independently while not presenting any lymph node activity, which has not been reported before.

Comparison of the 68 Ga-FAPI Versus 18 F-FDG in Gastric Adenocarcinoma and Anthracosis-Associated Lymph Nodes: FAPI Unmasking False-Negatives and False-Positives.

ABSTRACT: A 73-year-old woman with poorly differentiated gastric adenocarcinoma was referred to 18 F-FDG PET/CT for evaluation of the disease. FDG PET/CT showed intense uptake in the disseminated lymph nodes. However, there was no uptake in the primary tumoral lesion. Subsequently, 68 Ga-FAPI-04 PET/CT was performed with the decision of the tumor board and demonstrated intense uptake in the tumoral lesion. However, there was low or no uptake in disseminated lymph nodes. Tru-cut biopsy results revealed that all the lymph nodes were associated with anthracosis.

Comparison of Planar Imaging Using Dual-phase Tc-99m-sestamibi Scintigraphy and Single Photon Emission Computed Tomography/Computed Tomography in Hyperparathyroidism.

Objectives: The aim of this study was to compare Technetium-99m (Tc-99m)-sestamibi dual-phase planar imaging method and delayed phase single photon emission computed tomography/computed tomography (SPECT/CT) imaging in patients with primary hyperparathyroidism and to evaluate the accuracy of scintigraphy with histopathological results. Methods: Thirty-six patients with a prediagnosis of hyperparathyroidism, who had not been operated on the neck region before, and were not followed up for any other malignancy, and has confirmed histopathologic and biochemical diagnosis after parathyroidectomy, were retrospectively scanned and included in the study. The images of 36 patients who underwent dual-phase Tc-99m-sestamibi planar scintigraphy at the 20th and 120th minutes in the nuclear medicine clinic and delayed phase SPECT/CT imaging immediately after the 120th minute planar imaging were evaluated visually by two nuclear medicine specialists as positive or negative lesion. Dual-phase planar and SPECT/CT images were statistically compared in terms of sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. Results: Thirty-six patients with 41 lesions were evaluated. Comparing dual-phase planar imaging and delayed phase SPECT/CT revealed, sensitivity 84.21%-94.74%, specificity 66.67%-66.67%. Positive predictive value 96.97%-97.30%, negative predictive value 25%-50.0%, accuracy 82.93%-92.68% respectively. There was a statistically significant difference between planar imaging and SPECT/CT; SPECT/CT localized the lesion more accurately (p<0.05). Conclusion: SPECT/CT is superior to planar imaging in determining the anatomical details and localization of the lesion, especially in determining the depth of the lesions in the neck and whether it is ectopic. In patients with hyperparathyroidism, SPECT/CT should be used routinely to detect parathyroid pathologies because it has a lower rate of error and higher accuracy rate.

A Rare Case of Differentiated Thyroid Carcinoma with Liver Metastases.

Papillary thyroid carcinoma (PTC) is the most frequent type of differentiated thyroid cancers (DTCs) and commonly metastasizes to regional lymph nodes. Distant metastases of DTC typically occur in the lungs and bones. Liver metastases of DTC are very rare and difficult to diagnose. We present a case of a 52-year-old woman who had a previous history of PTC treated by total thyroidectomy and lymph node dissection. The patient received two radioactive iodine-131 (I-131) treatments. The second postradioiodine therapy whole-body scan (WBS) revealed intense iodine uptake in the neck region and in the lungs. After 2 months, during the follow-up period, increase in serum thyroglobulin (Tg) level was detected. Positron-emission tomography-computed tomography (PET-CT) with 18F-fluorodeoxyglucose (FDG) revealed increased FDG uptake in the mass lesion that invaded the muscles in the neck area, lung, bone, and liver. The uptake in liver was interpreted as suspicion of malignancy. The trucut biopsy of the liver masses demonstrated metastases of the thyroid carcinoma with the immunohistochemical thyroid transcription factor-1 and PAX8 positivity observed in these tumor cells. In DTC patients with progressive rapid rise of Tg level, the diagnostic value of I-131 WBS will decrease as the differentiation of the tumor decreases. The combined use of I-131 WBS and FDG PET-CT as diagnostic modalities in these patients will be important in treatment planning in detecting locoregional or distant metastases, especially in patients with negative diagnostic I-131 WBS.

Artificial intelligence technologies in nuclear medicine.

The use of artificial intelligence plays a crucial role in developing precision medicine in nuclear medicine. Artificial intelligence refers to a field of computer science aimed at imitating the performance of tasks typically requiring human intelligence. From machine learning to generative adversarial networks, artificial intelligence automized the workflow of medical imaging. In this mini-review, we encapsulate artificial intelligence models and their use in nuclear medicine imaging workflow.

The Evaluation of Preoperative 18F-FDG PET/CT in Patients with Endometrial Cancer and the Correlation Between PET Parameters and Postoperative Pathology Results.

OBJECTIVES: Endometrial cancer (EC) is the most common gynecological malignancy. The 18fluorine-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is used for initial staging, evaluating treatment response, and detecting recurrence. This study aimed to investigate the diagnostic value of preoperative PET/CT in EC staging and determine the volumetric PET parameters that are accurate predictors of histopathological tumor characteristics. METHODS: Preoperative PET/CT data of 66 patients with EC were retrospectively analyzed. Patients were divided into low and high-risk groups according to the European Society for Medical Oncology criteria. The maximum standardized uptake value (SUVmax), SUVmean, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary lesion and pathological lymph nodes were noted. The International Federation of Gynecology and Obstetrics (FIGO) classifications, histopathology, the depth of myometrial invasion (MI), lymph node metastasis (LNM), cervical stromal invasion (CSI), and tumor sizes were noted. RESULTS: The SUVmax, TLG, and MTV values of high and low-risk groups were significantly different. TLG was the most useful parameter in differentiating risk groups. PET/CT had 90% sensitivity, 96.3% specificity, 81.8% positive predictive value, 98.1% negative predictive value, and 95.45% accuracy in assessing LNM. MTV and TLG values in patients with non-endometrioid pathology were higher than those with endometrioid. The SUVmax, MTV, and TLG of patients with deep MI were higher than those with superficial MI. TLG values of patients with CSI were higher than those without CSI. Patients with LNM had higher MTV and TLG values than those without LNM. A significant difference was found in TLG, MTV, and SUVmax values between patients with FIGO stage I-II and patients with FIGO stage III and above. CONCLUSION: SUV and volumetric parameters obtained from PET/CT, especially TLG, are strong predictors of tumor characteristics, such as MI and CSI, FIGO stages, and LNM, and are useful in noninvasively defining the risk groups in the preoperative period.

A case of soft tissue hematoma detected incidentally on 99m TC-labelled RBC gastrointestinal bleeding SPECT/CT.

We report an incidental finding on 99mTc-labelled RBC gastrointestinal bleeding scintigraphy of a 49-year-old female patient referred to our clinic in order to localize the bleeding site. The patient has also been suffering from chronic renal insufficiency and received several interventions of femoral catheterization. During the follow-up, an intense uptake was observed at the right inguinofemoral area which is evaluated as a large soft tissue hematoma and confirmed by SPECT/CT subsequently. On the 24th h delayed image an activity accumulation along the bowel trace on the right side of the abdomen was seen as evidence of lower gastrointestinal bleeding.

Correlations of 68Ga-PSMA PET/CT in the initial staging of prostate cancer patients.

OBJECTIVE: The aim of this study was to evaluate the correlations between the different risk groups of prostate cancer (PCa) regarding the presence of metastasis and the gallium-68 prostate specific membrane antigen (68Ga-PSMA) uptake patterns in the prostate gland. MATERIALS AND METHODS: One hundred thirty nine patients with newly diagnosed, untreated PCa who underwent 68Ga-PSMA PET/CT imaging for staging between July 2017 and March 2019 were enrolled in this retrospective study. Maximum standardized uptake values (SUVmax) were determined by manually placing the region of interest to the primary tumor in the prostate gland. Patients were divided into groups according to their prostate-specific antigen (PSA) values, International Society of Urological Pathology (ISUP) grade groups, Gleason Scores (GS), D'Amico risk stratification criteria and the presence of metastasis. Mann Whitney U test was used in the comparison of two groups of data. In multivariate analysis, logistic regression was used to determine independent predictors for the presence of metastasis. RESULTS: There were statistically significant differences between D'Amico risk groups in terms of prostate SUVmax levels. The SUVmax levels of the patients in the high risk group were significantly higher than the SUVmax levels of the patients in the low-medium risk groups (P<0.001). Maximum standardized uptake value levels of the patients with PSA level 20ng/mL and above were significantly higher than those with PSA level below 20ng/mL (P<0.001). The metastatic rate of patients with 68Ga-PSMA uptake on two lobes of the prostate gland was significantly higher (42.6%) than the metastatic rate of patients with 68Ga-PSMA uptake on only one lobe (7.9%) (P<0.001).The median SUVmax of tumours in patients with metastasis was statistically significantly higher than in patients with no metastasis. In multivariate analysis; bilobar involvement, PSA value 20ng/mL, prostate SUVmax value 8.6 and GS 8 were determined as independent predictors for the presence of metastasis. CONCLUSION: The strong correlation between PSA values and/or Gleason score/Grade and SUVmax values suggests that the SUVmax value of the prostate gland might be a valuable determinant in risk classifications.

Differentiated thyroid carcinoma in children: Clinical characteristics and long-term follow-up.

Differentiated thyroid cancer (DTC) is rare in children, but it still remains the most common endocrine malignancy in children. The aim of this study was to analyze treatment response to radioactive iodine (RAI) therapy, clinical outcomes, recurrences, survival analysis, and long-term follow-up. We retrospectively reviewed the medical records of 43 pediatric patients (≤17 years of age) with DTC diagnosis after thyroidectomy who were treated with RAI. The follow-up protocol consisted of detailed clinical examination, testing of thyroid function, determination of serum thyroglobulin (Tg), and anti-Tg antibodies, and neck ultrasonography application. Forty-three pediatric patients (34 females and 9 males) treated with RAI for DTC in our institute. The median follow-up period was 54 months. The histologic classification was papillary thyroid cancer in 41 patients and the remaining 2 patients had follicular thyroid cancer. After the long-term follow-up, complete remission, partial remission, and recurrent-persistent disease were observed in 37 patients, 3 patients, and 3 patients, respectively. Among the series, 1 death occurred due to multiple metastases. The mortality rate is 2.56%. Total thyroidectomy followed by RAI appears to be the most effective treatment for patients with pediatric DTC in terms of reducing the rate of relapse and improving surveillance for recurrent disease.

THE COMPARISON OF THE EXTERNAL DOSE RATE MEASUREMENT OF CHILDREN AND ADOLESCENT PATIENTS WITH ADULT PATIENTS TREATED WITH RADIOIODINE THERAPY.

The aim of this study is to evaluate the radiation safety of caregiving people contacting the child and adolescent patients with thyroid cancer who received radioactive iodine-131 (RIT) treatment by comparison with external dose rate measurements of adult patients according to their administered activities and days of hospitalization. We retrospectively evaluated external dose rate measurement of 158 children and adolescent patients and 158 adult patients. During the RIT, the hospitalization time were grouped as 2, 3 and 4 d, and the administered activities as <3700, 3700 and >3700 MBq. The values of external dose rate measurements of children and adolescents were statistically significantly higher than the adult group. Different approaches in radiation safety rules are required for children and adolescents. In terms of radiation safety, we suggest that more specific regulations for family members and caregivers should be established and informed.

Prognostic significance of maximum standardized uptake value on 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography in bone sarcomas.

OBJECTIVES: This study aims to evaluate the prognostic significance of maximum standardized uptake value (SUVmax) on 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography (18FDG-PET/CT) for bone sarcoma. PATIENTS AND METHODS: We retrospectively evaluated 34 patients (24 males, 10 females; mean age 36.6±24.2 years; range, 5 to 77 years) with pathologically proven bone sarcoma who underwent 18FDG-PET/CT for initial staging between September 2013 and September 2017. SUVmax of primary lesions were measured. Cumulative survival rate was calculated to evaluate the prognostic value of 18FDG-PET/CT findings. Survival duration was defined as the elapsed duration from the date of pre-treatment 18FDG-PET/CT scanning until the date of the final examination before the date of death. RESULTS: The cut-off value for SUVmax in the definition of progression was 8. Mean SUVmax of the progressive group was statistically significantly higher than the non-progressive group. Distant metastases were present in 14 (41.1%) cases. Mortality and cumulative survival rates were 14.7% and 79.1±0.08%, respectively. CONCLUSION: Semiquantitative estimation of primary tumor metabolic activity in terms of baseline SUVmax using 18FDG-PET/CT can predict the overall survival of patients with bone sarcoma.

The Accuracy of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Bone Lesions of Undetermined Origin.

The aim of the current study was to determine the diagnostic accuracy of whole-body fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in detecting carcinoma of unknown primary (CUP) with bone metastases. We evaluated 87 patients who were referred to FDG-PET/CT imaging and reported to have skeletal lesions with suspicion of malignancy. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated. The median survival rate was measured to evaluate the prognostic value of the FDG-PET/CT findings. In the search for a primary, FDG-PET/CT findings correctly diagnosed lesions as the site of the primary true positive (TP) in 64 (73%) cases, 4 (5%) findings diagnosed no site of a primary, and none were subsequently proven to be true negative (TN); 14 (16%) diagnoses were false positive (FP) and 5 (6%) diagnoses were false negative (FN). Life expectancy was between 2 months and 25 months. Whole-body FDG-PET/CT imaging may be a useful method in assessing the bone lesions with suspicion of bone metastases.

The Value of Attenuation Correction in Hybrid Cardiac SPECT/CT on Inferior Wall According to Body Mass Index.

The purpose of this study was to evaluate the diagnostic value of attenuation-corrected single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) on the inferior wall compared to uncorrected (NC) SPECT MPI between obese and nonobese patients. A total of 157 consecutive patients (122 males and 35 females, with median age: 57.4 ± 11 years) who underwent AC technetium 99m-methoxyisobutylisonitrile (AC Tc99m-sestamibi) SPECT MPI were included to the study. A hybrid SPECT and transmission computed tomography (CT) system was used for the diagnosis with 1-day protocol, and stress imaging was performed first. During attenuation correction (AC) processing on a Xeleris Workstation using Myovation cardiac software with ordered subset expectation maximization (OSEM), iterative reconstruction with attenuation correction (IRAC) and NC images filtered back projection (FBP) were used. For statistical purposes, P < 0.05 was considered significant. This study included 73 patients with body mass index (BMI) <30 and 84 patients with BMI ≥ 30. In patients with higher BMI, increased amount of both visual and semiquantitative attenuation of the inferior wall was detected. IRAC reconstruction corrects the diaphragm attenuation of the inferior wall better than FBP. AC with OSEM iterative reconstruction significantly improves the diagnostic value of stress-only SPECT MPI in patients with normal weight and those who are obese, but the improvements are significantly greater in obese patients. Stress-only SPECT imaging with AC provides shorter and lower radiation exposure.

Arthroscopic Excision of Acetabular Osteoid Osteoma: Computer Tomography-Guided Approach.

Osteoid osteoma is a benign osteoblastic tumor that occurs in the subcortical shaft and metaphysis of the long bones of the lower extremities; however, intra-articular lesions are also possible. Intra-articular osteoid osteomas are rare, and clinical symptoms are often less specific and, thereby, may lead to misdiagnosis. The definitive treatment for osteoid osteoma is the excision of the nidus. We present the case of a 23-year-old man with a 4-year history of right anterior hip pain, subsequently diagnosed with a subarticular osteoid osteoma located in the right anterior acetabulum. Hip arthroscopic excision of the juxta-articular osteoid osteoma is presented as an effective treatment, with the advantage of less potential damage to normal bone and cartilage, as well as the additional benefits available with hip arthroscopy.

Diagnostic value of single-photon emission computed tomography combined with computed tomography in relation to MRI on osteochondral lesions of the talus.

BACKGROUND: Osteochondral lesion of the talus (OLT) involves the separation of a fragment of articular cartilage, as defined by Kappis in 1922. MRI is the current standard for noninvasive diagnosis of OLT. Single-photon emission computed tomography combined with computed tomography (SPECT/CT) provides both morphologic and functional information. The purpose of the study was to compare SPECT/CT with MRI for image interpretation and treatment decision making in talar osteochondral lesions. MATERIALS AND METHODS: A total of 21 patients (four bilateral) were evaluated with MRI and SPECT/CT. Diagnostic arthroscopy was performed to validate the indication by identifying unstable cartilage areas. Activation was assessed in nine regions of interest, as described by Elias and colleagues. SPECT/CT findings were assessed by the modified scoring system of Hart and colleagues, and MRI findings with the modified classification system of Hepple and colleagues. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated for SPECT/CT and MRI. RESULTS: A total of 25 lesions were identified. Seventeen lesions were located on the medial third of the talar dome, eight on the lateral third, and seven on the central third. Four patients revealed diffuse uptake on more than one zone on SPECT/CT. SPECT/CT identified two subchondral lesions, which were not visualized on MRI. CONCLUSION: MRI is the current standard for OLT diagnosis. SPECT/CT allows a three-dimensional localization of scintigraphic osteoblastic activity in the area of interest, providing additional information about the involvement of the subchondral bone and the vitality of the osteochondral lesion and the location of multiple lesions. We recommend the use of SPECT/CT and MRI together for comprehensive diagnostic assessment of OLT.

Pseudoaneurysm of a pancreas allograft artery detected by 99mTc red blood cell SPECT/CT.

We present a case of obscure gastrointestinal bleeding associated with a large pseudoaneurysm in the splenic artery after simultaneous kidney-pancreas transplantation. Planar 99mTc red blood cell (RBC) scintigraphy demonstrated a focus of increased activity in the mid-abdomen, which was confirmed by SPECT/CT to be in the region of the pancreatic transplant. Subsequent diagnostic CT angiography of the abdomen identified a large pseudoaneurysm of the pancreas allograft splenic artery. At surgery, an arterial-enteric fistula was confirmed at the site of aneurysm coiling, and this segment of bowel was removed.

The effect of high dose radioiodine therapy on formation of radiation retinopathy during thyroid cancer treatment.

OBJECTIVE: Non-thyroidal complication of high-dose radioiodine therapy for thyroid carcinoma might cause salivary and lacrimal gland dysfunction, which may be transient or permanent in a dose-dependent manner. However, radiation retinopathy complicating 131I therapy, has not been previously well characterized. The aim of this study was to evaluate the extent of retinal damage among patients who had received high doses of radioiodine treatment. METHODS: Forty eyes of 20 patients (3 male, 17 female) who received 250-1000 mCi during 131I therapy and on ophthalmological follow up for a year after the last treatment were included in the study. Mean age of the study group was 50 years (range 25-70 years). In ophthalmologic examination, visual acuity was measured in order to determine visual loss. Intraocular pressure was measured in all the patients. Then lens examination was carried out with slit lamp biomicroscopy in order to investigate cataract or partial lens opacities. Fundus observation was carried out through the dilated pupil with slit lamp biomicroscopy using 90 D noncontact lens. RESULT: The best corrected visual aquity with Snellen chart was found as 1.0 in 36 eyes (90%) and between 0.6 and 0.9 (10%) in 4 eyes (10%). At the biomicroscopic fundus examination, retinal hemorrhage consistent with radiation retinopathy, microaneurysm, microinfarction, edema or exudation, vitreus hemorrhage, partial or total optical disc pallor indicating papillopathy in the optic disc were not observed in any of the eyes. CONCLUSION: This result indicates that there is not any significant correlation between repeated high-dose radioiodine therapy and radiation retinopathy in differentiated thyroid carcinomas. Even though there is not a significant restriction in use of higher doses of radioiodine therapy in differentiated thyroid carcinoma, more extensive studies are needed in order to obtain more accurate data on possible occurrence of retinopathy.

Differentiation of incidental intestinal activities at PET/CT examinations with a new sign: Peristaltic segment sign / Signo del segmento peristáltico: un nuevo signo del examen PET/TAC para el diagnóstico diferencial de las actividades intestinales incidentales

Purpose. The aim of this study was to present the effect of the peristaltic segment sign for the differential diagnosis between malignant, physiological and gastrointestinal focal fluorodeoxyglucose (FDG) uptakes as an alternative method to maximum standardized uptake value (SUVmax). Materials and methods. Gastrointestinal tract (GIT) sections of 823 FDG positron emission tomography/computed tomography (FDG-PET/CT) performed in our center were reviewed retrospectively. Images of these cases that have been reported for positive intestinal focal FDG uptake areas were included. Through the sectional images, any accompanying short segment expanded with air just after or before the uptake area was marked as “positive peristaltism sign”. The cases were confirmed with endoscopy plus biopsy (n:42), endoscopy (n:5), laparotomy (n:1), transabdominal biopsy (n:1), enteroclysis (n:1), CT-colonoscopy (n:5), rectal contrast enhanced CT (n:4). Distinguishing features of the sign were analyzed statistically compared to the conventional method for differentiation of malignity. Results. Localized FDG uptake was reported in 59 of 823 cases. A SUVmax greater than 2.5 with intestinal wall thickening allowed the diagnosis of malignity with sensitivity 33%, specificity 65%, positive predictive value 69% and negative predictive value 46%. The peristaltic segment sign, considered as a benign finding, increased the statistical values to 68%, 80%, 82% and 65%, respectively. Conclusion. In case of gastrointestinal increased focal FDG uptake, the new parameter of peristaltic segment sign may differentiate the physiologic uptakes from the malignant ones more accurately than the conventional SUVmax (AU)

Objetivo. El objetivo de este estudio fue presentar el efecto del signo del segmento peristáltico en el diagnóstico diferencial, maligno o fisiológico, de las captaciones focales de FDG detectadas en el tracto gastrointestinal (GIT) como un nuevo parámetro alternativo al SUVmax. Material y métodos. Se revisaron retrospectivamente las secciones del GIT de 823 estudios PET/TAC con FDG en los que se informaron la presencia de una captación focal intestinal de FDG. Se identificó como “signo peristáltico positivo” cualquier segmento intestinal que contenía aire antes o después del área de captación de FDG. Los casos se confirmaron por endoscopia con biopsia (42), endoscopia (5), laparotomía (1), biopsia transabdominal (1), enteroclisis (1), colonoscopia virtual (5) y TAC abdominal con contraste rectal (4). Los rasgos característicos del signo se analizaron estadísticamente comparados al método convencional para diferenciar malignidad. Resultados. La captación localizada de FDG se informó en 59 de los 823 casos. Un SUV mayor de 2.5 con engrosamiento de la pared intestinal permitió el diagnóstico diferencial de malignidad con sensibilidad 33%, especificidad 65%, valor predictivo positivo 69% y valor predictivo negativo 46%. El signo del segmento peristáltico, considerado como un hallazgo benigno, aumentó significativamente los valores a 68%, 80%, 82% y 65%, respectivamente. Conclusión. Cuando se detecta un aumento focal de captación de FDG en el GIT, el signo del segmento peristáltico, como un nuevo parámetro, puede diferenciar la captación fisiológica de la captación maligna de forma más exacta que el SUV (AU)

Differentiation of incidental intestinal activities at PET/CT examinations with a new sign: peristaltic segment sign.

PURPOSE: The aim of this study was to present the effect of the peristaltic segment sign for the differential diagnosis between malignant, physiological and gastrointestinal focal fluorodeoxyglucose (FDG) uptakes as an alternative method to maximum standardized uptake value (SUVmax). MATERIALS AND METHODS: Gastrointestinal tract (GIT) sections of 823 FDG positron emission tomography/computed tomography (FDG-PET/CT) performed in our center were reviewed retrospectively. Images of these cases that have been reported for positive intestinal focal FDG uptake areas were included. Through the sectional images, any accompanying short segment expanded with air just after or before the uptake area was marked as "positive peristaltism sign". The cases were confirmed with endoscopy plus biopsy (n:42), endoscopy (n:5), laparotomy (n:1), transabdominal biopsy (n:1), enteroclysis (n:1), CT-colonoscopy (n:5), rectal contrast enhanced CT (n:4). Distinguishing features of the sign were analyzed statistically compared to the conventional method for differentiation of malignity. RESULTS: Localized FDG uptake was reported in 59 of 823 cases. A SUVmax greater than 2.5 with intestinal wall thickening allowed the diagnosis of malignity with sensitivity 33%, specificity 65%, positive predictive value 69% and negative predictive value 46%. The peristaltic segment sign, considered as a benign finding, increased the statistical values to 68%, 80%, 82% and 65%, respectively. CONCLUSION: In case of gastrointestinal increased focal FDG uptake, the new parameter of peristaltic segment sign may differentiate the physiologic uptakes from the malignant ones more accurately than the conventional SUVmax.

Intraocular and orbital metastasis as a rare form of clinical presentation of insular thyroid cancer.

Insular carcinoma of thyroid is a rare tumor, which accounts for 4 to 6% of thyroid malignancies. Clinically and morphologically it is considered to be in an intermediate position between well-differentiated carcinoma of the thyroid (papillary or follicular) and undifferentiated or anaplastic carcinoma of the thyroid. Capsular and blood vessel invasion is seen frequently, and metastases to regional lymph nodes, lungs and bones are common. The initial presentation of distant metastasis in patients with thyroid cancer is rare. Thus metastatic thyroid carcinoma rarely involves the orbit. We report a rare case of choroidal metastasis from insular thyroid carcinoma.