Browsing by Author "Aktas, Ayse"

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Cardiac Blood Pool Activity on Postablation Radioiodine Imaging
(2015) Aktas, Ayse; Kocabas, Beyza; Erhamamci, Seval; Gencoglu, Arzu; Liman, Cevdet; 0000-0003-4631-1683; 0000-0003-0149-2265; 25381484; ABG-1864-2020; AAI-8772-2021
There are reports on physiologic and pathologic mediastinal uptake on radioiodine imaging in patients with thyroid carcinoma. The most commonly reported physiologic causes of mediastinal uptake are esophageal retention of salivary secretion and uptake by hyperplastic or normal thymus gland. In this study, we evaluated physiologic cardiac blood pool (CBP) activity and its associated findings on radioiodine imaging. Cardiac blood pool activity was evaluated in 186 postablation and 32 posttherapy scans. After oral radioiodine administration, imaging was initiated on day 7. Thyroglobulin, anti-thyroglobulin and TSH blood level determination was carried out in all patients. Whole-body scans were inspected with regard to residual thyroid uptake, esophageal uptake, CBP activity, hepatic activity and metastatic iodine uptake. Uptake in the residual thyroid tissue was graded visually as mild (m), moderate (M) and significant (S). Whenever CBP activity was detected on visual inspection, its intensity was graded as mild (1), moderate (2), and significant (3). Cardiac blood pool activity was detected in 61 postablation scans (33 %). Residual thyroid uptake was observed in all patients with CBP. A significant correlation existed between the intensity of uptake and the presence of CBP (p < 0.05). The mean Tg in patients with CBP was significantly higher than those without CBP (p < 0.05). Cardiac blood pool activity was not observed in any posttherapy scans and in those scans with distant metastases in the postablation group. Linear or irregular activity pattern thought to be due to esophagus was detected in 4 % of postablation scans. The results have revealed CBP to be common on postablation scans. Its presence correlated with the intensity of residual thyroid uptake and had a significant association with increased thyroglobulin levels. Its absence on posttherapy scans despite increased Tg levels suggested that this activity is due to labeled thyroid hormones released by the residual thyroid tissue. Its presence might imply a high level of blood radiation dose.
Diagnostic Significance of the Hepatic Parenchymal Retention Index as Determined by Hepatobiliary Scintigraphy in Liver Transplant Recipients
(2014) Gencoglu, Esra Arzu; Aktas, Ayse; Haberal, Mehmet; https://orcid.org/0000-0003-4631-1683; https://orcid.org/0000-0003-0149-2265; https://orcid.org/0000-0002-3462-7632; 24635801; ABG-1864-2020; AAI-8772-2021; AAJ-8097-2021
Objectives: The aim of this study was to evaluate the usefulness of the hepatic parenchymal retention index in the early diagnosis of parenchymal complications in liver transplant recipients as determined by hepatobiliary scintigraphy. Materials and Methods: This retrospective study reviewed 100 liver transplant recipients who had undergone orthotopic liver transplant. In all cases, hepatobiliary scintigraphy images recorded 7 to 10 days posttransplant were quantitatively reinterpreted according to hepatic parenchymal retention index. The hepatocyte extraction fraction value was also calculated. Scintigraphic findings as well as clinical, laboratory, and biopsy results were assessed. Results: Quantitative analysis showed normal hepatocyte extraction fraction value in all subjects. However, significant differences in hepatic parenchymal retention index were observed. Thus, subjects were divided into 3 groups: group 1 (n=75), normal; group 2 (n=15), severely elevated; group 3 (n=10), mildly-to-moderately elevated hepatic parenchymal retention index. Evaluation of histopathological, clinical, and laboratory findings showed normal grafts in all group 1 recipients, acute rejection in all group 2 recipients, and hepatocyte damage/intrahepatic cholestasis in all group 3 recipients. Conclusions: Based on these findings, we determined that hepatocyte extraction fraction value was not useful, whereas hepatic parenchymal retention index was beneficial for early and accurate diagnosis of parenchymal complications in liver transplant recipients.
The Effectiveness of Low- Dose Versus High- Dose 99m Tc MIBI Protocols for Radioguided Surgery in Patients with Primary Hyperparathyroidism
(2014) Gencoglu, Esra A.; Aras, Murat; Moray, Gokhan; Aktas, Ayse; https://orcid.org/0000-0003-4631-1683; https://orcid.org/0000-0003-2498-7287; https://orcid.org/0000-0003-0149-2265; 24323310; ABG-1864-2020; AAE-1041-2021; AAI-8772-2021
ObjectiveThe aim of this study was to compare the efficacy of low-dose and high-dose Tc-99m methoxy isobutyl isonitrile (MIBI) protocols in intraoperative localization of parathyroid adenomas by means of a gamma probe in patients with primary hyperparathyroidism (PHPT).Patients and methodsThe study included 62 patients with PHPT who were divided into two groups. Group 1 consisted of 32 patients who were injected with a low dose (1 mCi) of Tc-99m MIBI in the surgical suite 10 min before incision. Group 2 included 30 patients who were intravenously administered a high dose (15 mCi) of Tc-99m MIBI 2 h before surgery. With the aid of a gamma probe, intraoperative localization of parathyroid adenomas was performed in both groups of patients who underwent minimally invasive parathyroidectomy. All lesions thought to be parathyroid adenomas were excised and subsequently evaluated histopathologically.ResultsAll parathyroid adenomas in both groups were localized and excised by means of an intraoperative gamma probe. The sensitivity, specificity, and accuracy of low-dose and high-dose Tc-99m MIBI protocols in the intraoperative localization of adenomas in patients with PHPT were 100%.ConclusionIn the light of these findings, we conclude that low-dose Tc-99m MIBI may be preferred to intraoperative identification of parathyroid adenomas by means of a gamma probe in PHPT patients because it appears to be as effective as high-dose Tc-99m MIBI. Moreover, the low-dose protocol does not have the disadvantages of high-dose protocol.
The Efficacy of Low and High Dose 99mtc-MIBI Protocols for Intraoperative Identification of Hyperplastic Parathyroid Glands in Secondary Hyperparathyroidism
(2014) Gencoglu, Esra Arzu; Aktas, Ayse; https://orcid.org/0000-0003-4631-1683; https://orcid.org/0000-0003-0149-2265; 24703993; ABG-1864-2020; AAI-8772-2021
Objective: The aim of this study was to compare the efficacy of low- and high-dose Tc-99m-MIBI protocols for intraoperative identification of hyperplastic parathyroid glands via gamma probe in secondary hyperparathyroidism. Material and Methods: This retrospective study was conducted using a prospective database of 59 patients who had undergone radioguided subtotal parathyroidectomy between 2004-2012. The patients were studied in 2 groups. Group 1 (n=31) received 37 MBq Tc-99m-MIBI intravenously in the surgical room approximately 10 mm before the beginning of the intervention and surgery was performed under gamma probe guidance. Group 2 (n = 28) received 555 MBq Tc-99m- MIBI intravenously 2 h before surgery, which was also performed under gamma probe guidance. Intraoperative gamma probe findings, laboratory findings, and histopathological findings were evaluated together. Results: Using acceptance of the histopathological findings as gold standard, sensitivity and specificity of intraoperative gamma probe for identifying hyperplastic parathyroid glands was 98% and 100%, respectively, in both groups. Conclusions: In the light of these findings, it is concluded that the low-dose Tc-99m-MIBI protocol might be preferable for intraoperative identification of hyperplastic parathyroid glands in secondary hyperparathyroidism patients because it was observed to be as effective as the high-dose Tc-99m-MIBI protocol. Furthermore, the low-dose protocol does not have the disadvantages that are associated with the high-dose protocol. (C) 2014 Elsevier Espana, S.L. and SEMNIM. All rights reserved.
Evaluation of cyclic direct radionuclide cystography findings with DMSA scintigraphy results in children with a prior diagnosis of vesicoureteral reflux
(2019) Torun, Nese; Aktas, Ayse; Reyhan, Mehmet; Yapar, A. Fuat; Nursal, G. Nihal; 0000-0003-0149-2265; 30741838
Objectives Direct radionuclide cystography (DRC) with cyclic imaging is a sensitive method used for the detection of vesicoureteral reflux (VUR). Radionuclide cystography is generally recommended for follow-up evaluation of VUR. The aim of this study was to evaluate cyclic DRC with DMSA scan results during the follow-up period in children with a prior diagnosis of VUR. Patients and methods DRC findings of 85 children with VUR were evaluated together with DMSA findings during follow-up. VUR grade was classified anatomically as grades I, II, and III reflux. Reflux grades of II and III were regarded as high-grade reflux. Reflux was also graded functionally as transient and continuous on the basis of the presence of reflux on either filling or voiding phases (transient) or both phases (continuous) of at least one cycle. Results Among 85 children, 32 (38%) exhibited reflux. In five patients, reflux was observed on both sides, and a total of 37 refluxing units (RUs) were evaluated. According to the highest grade attained in either cycle, 31 (84%) units had grade II, five had grade I and one had grade III reflux. Reflux was continuous in 23 (62%) and transient in 14 (38%) RUs. The incidence of an abnormal scan result was higher in continuous reflux group (78%) than in high-grade anatomic reflux group (59%). The addition of a second cycle resulted in the diagnosis of continuous reflux in six (26%) more RUs. DMSA scan findings correlated significantly with functional reflux classification (P<0.05), but not with anatomic reflux classification (P>0.05). Conclusion Functional classification of VUR into continuous and transient reflux resulted in higher correlation with DMSA scan findings compared with anatomic reflux grading in follow-up patients with VUR. Cyclic imaging contributed to continuous reflux diagnosis. The significance of functional information obtained from cyclic DRC in initial diagnostic workup, management, and follow-up of children with urinary tract infection needs to be determined with further studies.
Fragmented QRS on 12-Lead Electrocardiogram Is Correlated With Severe Coronary Artery Disease and Abnormal Myocardial Perfusion Scintigraphy Results in Renal Transplant Candidates
(2018) Ciftci, Orgun; Keskin, Suzan; Karacaglar, Emir; Yilmaz, Kerem Can; Aktas, Ayse; Sezer, Siren; Moray, Gokhan; Muderrisoglu, Ibrahim Haldun; Haberal, Mehmet; 0000-0001-8926-9142; 0000-0002-2538-1642; 0000-0003-2498-7287; 0000-0002-3462-7632; 30066622; W-5233-2018; ABI-6723-2020; AAJ-1331-2021; AAE-1041-2021; AAJ-8097-2021
Objectives: Coronary artery disease is a major cause of mortality and morbidity after renal transplant. Fragmented QRS on standard 12-lead electrocardiograms has been proposed as a marker of myocardial scar, mainly due to coronary artery disease. Here, we aimed to investigate fragmented QRS to detect severe coronary artery disease in renal transplant candidates. Materials and Methods: We retrospectively reviewed the medical records of 534 patients with end-stage renal failure who were on the deceased-donor renal transplant wait list at Baskent University Faculty of Medicine due to having no living kidney donor available. We evaluated patients with standard 12-lead electrocardiograms, myocardial perfusion scintigraphy, and coronary angiography. We compared fragmented QRS prevalence versus myocardial perfusion scintigraphy abnormalities and severe coronary artery disease. Correlations among these were analyzed. Results: Of 92 renal transplant candidates (median age of 56.5 y; range, 24-80 y), 87 patients (94.6%) had myocardial perfusion defects and 72 (78.3%) had myocardial wall motion abnormalities on myocardial perfusion scintigraphy. Forty-four patients (47.8%) had severe coronary artery disease on coronary angiography, and 51 patients (55.4%) had fragmented QRS. Fragmented QRS was significantly more common among patients with myocardial scar. Coronary artery disease was significantly more common in patients with fragmented QRS (P = .042) and in those with fragmented QRS combined with myocardial perfusion defects (P < .01). Fragmented QRS was significantly correlated with presence of myocardial scar and any perfusion defects. When combined with myocardial perfusion defects, fragmented QRS was significantly correlated with severe coronary artery disease (P < .05). Conclusions: Fragmented QRS was significantly correlated with abnormal myocardial perfusion scintigraphy and severe coronary artery disease in renal transplant candidates.This simple parameter can provide valuable information on severe coronary artery disease and help to prevent excess patient morbidity and mortality from this disease after renal transplant.
A Novel Cause of False-Positive Iodine-131 Whole Body Scintigraphy: Eczema
(2015) Gencoglu, Esra Arzu; Aktas, Ayse; Aras, Murat; 0000-0003-4631-1683; ABG-1864-2020
Transplanted Kidney Function Evaluation
(2014) Aktas, Ayse; https://orcid.org/0000-0003-0149-2265; 24484750; AAI-8772-2021
The best option for the treatment of end-stage renal disease is kidney transplantation. Prompt diagnosis and management of early posttransplantation complications is of utmost importance for graft survival. Biochemical markers, allograft biopsies, and imaging modalities are used for the timely recognition and management of graft dysfunction. Among several other factors, improvements in imaging modalities have been regarded as one of the factors contributing to increased short-term graft survival. Each imaging procedure has its own unique contribution to the evaluation of renal transplant dysfunction. In the era of multimodality imaging and emerging clinical considerations for the improvement of graft survival, evaluating an imaging modality in its own right may not be relevant and may fall short of expectation. Recognized as being mainly a functional imaging procedure, radionuclide imaging provides valuable information on renal function that cannot be obtained with other imaging. modalities. For evaluating and establishing the current place, indications, and potential applications of radionuclide renal transplant imaging, a classification of renal allograft complications based on renal allograft dysfunction is essential. The major factor affecting long-term graft loss is chronic allograft nephropathy. Its association with early posttransplantation delayed graft function and repeated acute rejection episodes is well documented. Long-term graft survival rate have not improve significantly over the years. Imaging procedures are most commonly performed during the early period after transplantation. There seems to be a need for performing more frequent late posttransplantation imaging for the evaluation of acute allograft dysfunction, subclinical pathology, and chronic allograft changes; for understanding their contribution to patient management; and for identification of pathophysiological mechanisms leading to proteinuria and hypertension. With its unique advantage of relating perfusion to function, the potential for radionuclide imaging to replace late protocol biopsies needs to be investigated. (C) 2014 Elsevier Inc. All rights reserved.