Mehmet Ozguven

Post-surgical ablation of thyroid remnants with high-dose 131I in patients with differentiated thyroid carcinoma

The aims of this study were to evaluate the efficacy of an empirically determined ‘fixed’ high ablative dose of radioiodine (131I) therapy and to determine the utility of ultrasonography (US) in dose determination. A retrospective analysis was performed of 242 thyroid cancer cases treated with ‘fixed’ high-dose 131I for ablation of thyroid remnants without a pre-ablative 131I diagnostic scintigraphy or radioiodine uptake study. Treatment doses ranged from 1850 MBq (50 mCi) to 7.4 GBq (200 mCi). The selection of the treatment dose was based on the surgical and pathological findings as well as the remnant thyroid volume calculated by US. A successful ablation was defined as the absence of activity in the thyroid bed on subsequent imaging studies. Successful ablation was obtained in 218 of the 242 patients (90%). In 162 of the 218 patients (74.3%), successful ablation was achieved after a single 131I treatment. The remnant thyroid volume calculated by US was significantly different (P = 0.04) between those who were successfully ablated and those who were not. The total 131I dose needed for successful ablation was significantly higher in males (P = 0.003). Patients with higher post-operative thyroglobulin (Tgb) levels and patients with a higher stage of disease required higher doses (P = 0.036 and P = 0.021 respectively). Serum Tgb levels were under 10 ng·ml−1 in 220 of the 242 patients (90%) following radioiodine ablation while not receiving L-thyroxine suppression. Nineteen patients (7.8%) showed metastases on post-therapy scan and successful treatment was achieved in 11 of 19 (57.8%). Four of the 19 patients with distant metastases (revealed on post-treatment scan) were found to have been given a treatment dose of less than 200 mCi based on the proposed empirical approach. These results indicate that ‘fixed’ high-dose 131I treatment is clinically feasible with an acceptable dose underestimation rate, and the utilization of US in the determination of the thyroid remnant volume provides more accurate and reproducible results.

Comparison of In-111 octreotide and Tc-99m (V) DMSA scintigraphy in the detection of medullary thyroid tumor foci in patients with elevated levels of tumor markers after surgery.

Purpose In this retrospective study, the authors evaluated the utility of In-111 octreotide (OctreoScan) and Tc-99m (V) DMSA scintigraphy for the localization of recurrent metastatic tumor foci in patients with medullary thyroid cancer (MTC) and compared the findings with those of conventional radiologic imaging methods. Methods The scintigraphic images were compared with computed tomography (CT) and magnetic resonance imaging (MRI) and ultrasonography (US) in 14 patients (8 men, 6 women; age range, 22 to 74 years) with elevated calcitonin and carcinoembryonic antigen levels after total thyroidectomy. All scintigraphic image findings were evaluated qualitatively as mild uptake (+) and moderate to marked uptake (++). Results In-111 octreotide may be superior to Tc-99m (V) DMSA for the detection of tumor foci of patients with MTC on a patient basis (78.5% versus 57.1%) and on a lesion basis (44.1% versus 30.2%). The sensitivity rate for In-111 octreotide (78.5%) was also similar to that of CT and MRI on a patient basis. Conversely, the combined use of Tc-99m (V) DMSA and In-111 octreotide revealed the best sensitivity rate (85.7%) on a patient basis, whereas the combined use of CT and MRI showed the best sensitivity rate (81.3%) on a lesion basis. Conclusions These findings suggest that In-111 octreotide is superior to Tc-99m (V) DMSA and has a similar sensitivity rate to CT and MRI for the diagnosis of recurrent or metastatic MTC. Although the combined use of In-111 octreotide and Tc-99m (V) DMSA was most sensitive, the combined use of CT and MRI with radionuclide imaging methods may better detect more metastatic tumor foci.

Evaluation of cerebral vasospasm in patients with subarachnoid hemorrhage using single photon emission computed tomography.

Cerebral vasospasm (CVS) occurs as a result of the breakdown in cerebral autoregulation mechanisms. Because cerebral vasospasm can occur after subrachnoid hemorrhage (SAH), it is important to evaluate borderline perfusion. Evaluation of borderline vascular insufficiency is important to reduce ischemic complications. In this study 25 patients with SAH were investigated by somatosensory evoked potentials (SEP), computed tomography (CT), digital subtraction angiography (DSA) and single photon emission computed tomography (SPECT) in order to predict borderline ischemic areas. Clinical grades were also correlated with these investigations. Thirteen patients had symptomatic vasospasm and 15 patients had angiographic vasospasm. SPECT showed hypoperfusion in 22 out of 25 patients. CT predicted CVS in 8 of these 22 patients. Our study shows that brain perfusion SPECT is a non-traumatic, non-invasive, non-allergic, inexpensive method for the prediction of cerebral vasospasm. We conclude that brain SPECT with Tc-99m HM-PAO is an accessible technique that can demonstrate varying degrees of regional tissue hypoperfusion in patients with delayed ischemic deficits due to CVS following SAH.

Utility of ventilation and perfusion scan in the diagnosis of young military recruits with an incidental finding of hyperlucent lung.

Swyer-James-MacLeod syndrome (SJMS) is considered to be a relatively uncommon disease presenting with unilateral hyperlucent lung due to hypoplasia of a pulmonary artery and bronchiectasis of the affected lung. In this report, we describe the ventilation-perfusion (V/Q) scan findings of nine male recruits (aged 20-29 years, mean 24.4±2.96 years) with SJMS in whom the diagnosis was first established in adulthood. V/Q scan findings of all patients were compared with those on planar radiographs, pulmonary function studies, high resolution computed tomography (HRCT) and digital subtraction angiography (DSA). The ventilation (133Xe) and perfusion (99Tcm-macro-aggregated albumin) scans showed the characteristic pattern of a matched V/Q defect and marked air trapping on the washout phase on 133Xe scintigraphy. HRCT displayed hypodense lung with integrity of main airways, and markedly diminished vasculature on the affected side in all patients. A smaller pulmonary artery on the affected side with poor peripheral vasculature was observed with DSA in all patients. All patients had features of obstructive airway disease in varying degrees on pulmonary function studies. In contrast to other imaging methods, bronchiectasis as an etiological factor was displayed on HRCT. Some pulmonary areas, which were normal on HRCT and planar radiographs, showed air trapping on V/Q scan. Although a V/Q scan was more helpful in determining the extent of the disease and correlates well with conventional imaging methods, HRCT was the most valuable imaging method for the evaluation of aetiology in unilateral hyperlucent lung.

Unusual patterns of I-131 contamination

Whole body imaging with radioiodine can detect functioning metastases, which can often be effectively treated with appropriate amounts of radioiodine. Non-physiologic I-131 uptake detected on images is usually interpreted as suggesting functioning thyroid metastases. However, extra-thyroidal I-131 accumulation does not always imply thyroid cancer metastases and has been reported on many occasions, including various non-thyroidal neoplasms, and contamination by body secretions. In order to avoid unnecessary therapeutic interventions it is extremely important to properly distinguish false-positive sites of I-131 localization. Three patients with unusual radioiodine contamination patterns, either presented for the first time or rarely presented in the existing literature, were reported. Reported cases consist of contamination in hair (due to styling hair with sputum), contamination in neck (due to drooling during sleep) and, contaminated chewing gum. False positive contamination sources were clarified by careful examination of patients and further images when necessary.

The visualization of granulomatous disease with somatostatin receptor scintigraphy

In-111 labeled pentetreotide scintigraphy was applied to three patients with proven granulomatous disease (two with sarcoidosis, one with tuberculosis). All revealed accumulation of ln-111 labeled pentetreotide in the granulomatous lesions, which was considered to be due to the presence of activated lymphocytes in these regions. This method may be of value in assessing the activity and extent of sarcoidosis and tuberculosis.

Combination of preoperative ultrasonographic mapping and radioguided occult lesion localization in patients with locally recurrent/persistent papillary thyroid carcinoma: a practical method for central compartment reoperations.

Purpose: To improve the surgical success and reduce the complication rates, we combine our routine preoperative ultrasound (US) mapping technique with radioguided occult lesion localization (ROLL) in patients with papillary thyroid cancer recurrences in central compartment. Materials and Methods: In the morning of surgery, biopsy proven recurrent/persistent tumoral lesions were plotted on a sketch and injected with Tc-99m labeled macroaggregated albumin under US guidance. Thyroid bed exploration was carried out based on the location of biopsy proven lesion with the guidance of intraoperative gamma probe and neck map. The lymphoadipose tissues showing high count rates were resected and labeled separately for histopathologic study. Results: Despite extensive scarring in some patients probe safely guided to lesions. Noninjected tumor foci were searched and successfully resected in the light of neck map that showing topographic relation of injected and noninjected lesions. Among total of 41 excised lesions, 28 metastatic foci ranging from 3 to 38 mm in largest diameter were recognized at final histologic examination. Combination of preoperative mapping with ROLL was found helpful by the operating surgeons in all patients, respectively. Except 2 patients with known distant metastases, undetectable thyroglobulin levels were reached 6 weeks after surgery. Conclusions: The use of preoperative US-mapping with ROLL in patients with nonpalpable recurrent/persistent papillary thyroid cancer in central compartment is technically safe and effective method. Combination of techniques provides better information about topographical relations of recurrent/persistent lesions during surgery.

Detection of widespread neurolymphomatosis with 18F-FDG PET

Brain MRI of a 21-year-old male with diffuse large B-cell lymphoma revealed lymphomatous infiltration in bilateral cavernous sinuses and fifth cranial nerves. Whole-body F-FDG PET revealed increased FDG uptake in the entire left brachial (a, left: solid arrow) and right lumbosacral plexus (middle), the proximal portion of the left lumbosacral plexus and areas around the cervical cord (a, left: dotted arrow). There was also increased FDG uptake in the spinal and sacral canal from T12 through the sacrum (a, right: solid arrow) as well as in multiple vertebrae, including the axis, C6 (a, right: dashed arrow), T5 and T11. In contrast, hypometabolism was noted in the L2 vertebral body (a, right: dotted arrow). MRI evaluation of these abnormal sites demonstrated enlargement and thickening of the right lumbosacral plexus, left proximal lumbosacral plexus (b, left) and left brachial plexus (b, middle). Dural thickening at the level of C6 through T2 was also noted. Diffuse leptomeningeal and dural infiltration obscured the conus medullaris and cauda equina from T12 to the sacral canal. MRI also depicted low T1 and high T2 signal intensity in the bone lesion in the L2 vertebral body (b, right). The infiltrated neural plexus, lumbar dura and bone lesion were enhanced mildly on intravenous contrast-enhanced series. These concordant PET and MRI findings suggested widespread neurolymphomatosis. Neurolymphomatosis is a rare neurological manifestation of systemic lymphoma [1]. The diagnosis is often difficult during lifetime and usually requires nerve biopsy [2]. Only a few case reports exist that show findings of neurolymphomatosis on CT, MRI and PET [3–5]. Although histopathological confirmation was unavailable, the concordant PET and MRI findings and the known systemic and cranial nerve involvement in this patient strongly suggest that the lesions were due to neurolymphomatosis. This approach to diagnosis is in concordance with the suggestions of Baehring et al.: in their extensive review, they added a surrogate criterion for neurolymphomatosis, in the form of CT, MRI or intraoperative evidence of nerve infiltration beyond the dural sleeve in the setting of known central nervous system or systemic lymphoma [6]. Emel Öztürk ()) Department of Nuclear Medicine, Gülhane Military Medical Academy and Medical School, 06018 Etlik, Ankara, Turkey e-mail: eozturk@gata.edu.tr Tel.: +90-312-3044806; Fax: +90-312-3044800

Performance of acidified 14C-urea capsule breath test during pantoprazole and ranitidine treatment.

Background and Aim:  Urea breath test (UBT) results could be false negative in patients taking antisecretory drugs. This effect would be prevented by citric acid administration during UBT. We prospectively investigated whether acidified 14C‐urea capsule prevents false negative UBT results in patients taking antisecretory drugs and show interference with the duration of medications.

Abnormal 18F-FDG Uptake Detected with Positron Emission Tomography in a Patient with Breast Cancer: A Case of Sarcoidosis and Review of the Literature

18F-FDG PET is a useful and sensitive imaging method for a variety of malignancies, however, the specificity is low in active infections and inflammatory diseases. We describe a female patient with stage IIIA breast cancer in first complete remission with combination chemotherapy who developed nodular formations in the lung and axilla 12 years later. Imaging studies as well as FDG PET showed nodular lesions and increased metabolic activity which was interpreted as the progression of the primary disease. She was first given combination chemotherapy and hormonal therapy but was proven thereafter to have sarcoidosis by pathologic examination and was successfully treated with corticosteroid treatment.