Y. Zeki Çelen

The role of FDG PET-CT in differential diagnosis of pleural pathologies

OBJECTIVE This study has aimed to evaluate the impact of (F18) Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography (FDG PET-CT) in the differential diagnosis of malignant and benign pleural lesions in patients with suspected malignant pleural mesothelioma (MPM). MATERIAL AND METHODS Fifty patients (32 females, 18 males; age range 24-79 years) with pleural thickening, fluid, plaques or calcification on previous CT scan were examined with FDG PET-CT. PET-CT imaging was obtained 1 h after FDG injection. In 12 patients, delayed imaging from the thoracic region was performed 2 h after injection. FDG uptake was evaluated visually and semiquantitively using standardized uptake value (SUV). FDG PET-CT findings were compared with histopathologic diagnosis. RESULTS Thirty-nine patients had increased FDG uptake in pleural lesions but PET-CT results were negative in 11 patients. When compared with histopathological results in FDG positive group, 34 patients had MPM, 5 had benign pathology; in FDG negative group 8 patients had benign pathology, 3 had MPM. Of patients with delayed imaging, 9 showed increased SUV but 3 had a decreased SUV on delayed images. Increased SUV group had 4 MPM, 5 benign pathology (3 chronic granulomatous inflammation, 2 benign asbestotic plaque). Decreased SUV group all had benign pathology (fibrosis, chronic inflammation, myofibrosis). DISCUSSION FDG PET-CT is a useful imaging modality in differential diagnosis of malignant and benign pleural lesions. Delayed imaging seems to be useful if there is a decrease in SUV suggesting a benign pathology but does not seem to contribute to the differential diagnosis if the SUV is increased.

Lung metastases in patients with differentiated thyroid carcinoma and evaluation of response to radioiodine therapy

INTRODUCTION The most common site of metastases in differentiated thyroid carcinomas is the lungs. In our study, we aimed to determine the ratios of lung metastases in patients with differentiated thyroid carcinoma and response to radioiodine therapy. MATERIAL AND METHODS A total of 542 patients with differentiated thyroid carcinoma who were admitted to our clinic were included in the study. High doses of (131)I were administered to the patients with lung metastases. Response to therapy were evaluated with (131)I scans and stimulated serum Tg levels were examined at least 6 months after therapy. RESULTS Lung metastases were detected in 17 (3.1%) of 542 patients with differentiated thyroid carcinoma. Of these patients to whom high doses of (131)I therapy were administered, complete response to therapy was obtained in 5 (29.4%), partial response was obtained in 3 (17.6%) and no response could be obtained in 9 (53%) patients. CONCLUSION Although lung metastases from differentiated thyroid carcinomas are rare, those are more common in advanced ages and in males. High doses of (131)I therapy may be partially beneficial in these patients. Thus repetition of therapy is frequently required.

Axillary lymph node metastasis of papillary thyroid carcinoma detected by FDG PET/CT in a thyroglobulin-positive patient with negative whole-body 131I scan.

Axillary metastasis is not a common finding in papillary carcinoma. 18F-FDG can detect foci of metastasis in patients with negative 131I scan. We report a case of a 64-year-old man who had undergone thyroidectomy and 131I ablation due to classic type of papillary carcinoma 14 years ago. Follow-up examination revealed high serum thyroglobulin and negative whole body 131I scan. 18F-FDG PET/CT showed focally increased uptake in right axillary as well as supraclavicular and bilateral cervical lymph nodes. Histopathological examination of the surgically removed lymph nodes confirmed the metastasis of papillary thyroid carcinoma.

A Different Concept in the Application of Dacryoscintigraphy

Purpose Current dacryoscintigraphy methods have several potential pitfalls, the most important of which is the outflow of tears. Another is the difficulty in fixing the head with the patient seated. To overcome these difficulties, a new method was applied. Materials and Methods The study included 77 persons: 43 controls and 34 patients with epiphora. Two methods were applied to the two groups. In the first, protocol 1 (the current conventional protocol), the patient was seated in front of a gamma camera and one drop (50 &mgr;l) Tc-99m pertechnetate containing 50 to 100 &mgr;Ci radioactivity was instilled in the inferior fornix or outer canthus of the eye and dynamic and static images were obtained for approximately 15 to 20 minutes. In the other, protocol 2 (our protocol), 100 &mgr;Ci (10 &mgr;l) Tc-99m pertechnetate was instilled in the outer canthus of the eye using a micropipette with the patient in the supine position under the gamma camera. Dynamic images were taken for only 5 minutes. Conclusion The pitfalls and difficulties seen with protocol 1 were lessened to a great degree in protocol 2.

Pulmonary arteriovenous malformation mimicking a pulmonary tumour on (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography.

Pulmonary arteriovenous malformations are rare congenital abnormal connections between the pulmonary arteries and veins. The patients are usually asymptomatic [1]. Although their aetiology is unclear, it is presumed that genetic abnormalities constitute a predisposition [1, 2]. An arteriovenous malformation might cause serious complications if it remains undiagnosed and untreated [3]. We report a unique case of focal 18F-fluorodeoxyglucose (18F-FDG) uptake in a pulmonary arteriovenous malformation mimicking a mass lesion. A 74-year-old female patient with cyanosis and clubbing in her fingers and toes was referred to the Nuclear Medicine Department for positron-emission tomography (PET)/computed tomography (CT) imaging to assess a solitary pulmonary nodule with irregular margins in the right upper lobe detected on CT (Figure 1A). The CT appearance suggested a malignant lesion. On 18F-FDG PET/CT, there was increased focal uptake in the pulmonary nodule, suggesting a mass lesion, possibly malignant (Figure 1B). There is no described typical uptake pattern for arteriovenous malformations in FDG PET/CT images. 18F-FDG accumulation in a pulmonary mass suggests malignancy in most cases, although FDG accumulates in several benign conditions. Pulmonary angiography revealed afferent and efferent vessels with high contrast accumulation. Based on these findings, a pulmonary arteriovenous malformation was diagnosed. Subsequently, the patient underwent right video-assisted thoracoscopic surgery, a mini-thoracotomy, and wedge resection. The specimen confirmed the diagnosis of pulmonary arteriovenous malformation (Figure 2). Figure 1 A – CT image showing a solitary pulmonary nodule in the anterior segment of the upper pole of the right lung. B – On 18F-FDG PET/CT, increased focal uptake was seen in the pulmonary nodule, suggesting a malignancy (SUVmax 4.2 kBq/ml) Figure 2 The specimen was stained with (A) haematoxylin and eosin and (B) Elastica van Gieson, which showed large and small vessels, confirming the diagnosis of pulmonary arteriovenous malformation Pulmonary arteriovenous malformations are often diagnosed radiologically [4–6]. A chest X-ray might reveal a solitary nodule or be completely normal. Thorax CT is usually the second diagnostic tool in a patient with a suspected pulmonary arteriovenous malformation [7, 8], which causes dyspnoea and cyanosis in most cases [1, 3]. Pulmonary angiography gives the ultimate diagnostic information [4, 8]. The CT appearance of our patients arteriovenous malformation suggested a malignant solitary mass. The moderately increased FDG uptake also caused diagnostic confusion. There is no typical uptake pattern of arteriovenous malformations in FDG PET/CT images.

Is it necessary to perform control diagnostic 131I whole body scan after remmant ablation in differentiated thyroid carcinoma patients who have stimulated Tg levels under 2 ng/ml?

Abstract Background: The aim of this retrospective study is to evaluate whether diagnostic I-131 whole body scan (DWBS) performed 6-12 months after thyroid remnant ablation is necessary or not in differentiated thyroid

Stimulated Tg level measurements may be avoided in differentiated thyroid carcinoma patients who have undetectable basal Tg levels

Abstract Background: The aim of this retrospective study is to evaluate the diagnostic value of undetectable basal thyroglobulin (Tg) levels measured 6 months after ablative 131I treatment (AIT) in patients

Original articleLung metastases in patients with differentiated thyroid carcinoma and evaluation of response to radioiodine therapyMetástasis pulmonar en pacientes con cáncer diferenciado de tiroides y evaluación de la respuesta a la terapia con radioyodo

Introduction The most common site of metastases in differentiated thyroid carcinomas is the lungs. In our study, we aimed to determine the ratios of lung metastases in patients with differentiated thyroid carcinoma and response to radioiodine therapy.

Kliniğimizde radyoaktif iyot tedavisi alan diferansiye tiroid karsinomlu hastaların demografik analizi

Our aim was to determine the correlation of a well differentiated thyroid carcinoma with gender and age. Our retrospective study evaluated 736 patients received ablation therapy between 2008 and 2011, consisted of 600 females and 136 males. The rate of female to male was 4,4/1 in differentiated thyroid carcinoma. Our patients aged between 14 to 89 during the diagnosis with a mean age of 46,9±12,8. The mean diagnosis age was 47,2±13,1 for females, while 46,1±13,3 for males. Papillary carcinoma was found as the most common type of tumor with 87% and the second common type was follicular carcinoma with 11%. In all type of thyroid cancers female patients were more than males. There was not any statistically significant difference between the mean diagnosis age for follicular thyroid cancer and for papillary thyroid cancer.