Aylin Oral

Fluorine-18 fluorodeoxyglucose PET-CT for extranodal staging of non-Hodgkin and Hodgkin lymphoma

PURPOSE We aimed to evaluate the role of fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) involving care-dose unenhanced CT to detect extranodal involvement in patients with non-Hodgkin and Hodgkin lymphoma. MATERIALS AND METHODS Lymphoma patients (35 Hodgkin lymphoma, 75 non-Hodgkin lymphoma) who were referred for 18F-FDG PET-CT imaging, following a diagnostic contrast-enhanced CT (CE-CT) performed within the last month, were included in our study. A total of 129 PET-CT images, and all radiologic, clinical, and pathological records of these patients were retrospectively reviewed. RESULTS In total, 137 hypermetabolic extranodal infiltration sites were detected by 18F-FDG PET-CT in 62 of 110 patients. There were no positive findings by CE-CT that reflected organ involvement in 40 of 137 18F-FDG-positive sites. The κ statistics revealed fair agreement between PET-CT and CE-CT for the detection of extranodal involvement (κ=0.60). The organs showing a disagreement between the two modalities were the spleen, bone marrow, bone, and thyroid and prostate glands. In all lesions that were negative at CE-CT, there was a diffuse 18F-FDG uptake pattern in the PET-CT images. The frequency of extranodal involvement was 51% and 58% in Hodgkin and non-Hodgkin lymphoma patients, respectively. There was a high positive correlation between the maximum standardized uptake values of the highest 18F-FDG-accumulating lymph nodes and extranodal sites (r=0.67) in patients with nodal and extranodal involvement. CONCLUSION 18F-FDG PET-CT is a more effective technique than CE-CT for the evaluation of extranodal involvement in Hodgkin and non-Hodgkin lymphoma patients. PET-CT has a significant advantage for the diagnosis of diffusely infiltrating organs without mass lesions or contrast enhancement compared to CE-CT.

Comparison of renal transplant scintigraphy with renal resistance index for prediction of early graft dysfunction and evaluation of acute tubular necrosis and acute rejection.

Purpose We discuss whether resistance index (RI) and renal scintigraphy obtained within 48 hours after operation could predict the early graft dysfunction. We also aimed to assess the uses of scintigraphy and RI in diagnosis of acute rejection (AR) and acute tubular necrosis (ATN). Methods A total of 153 studies were performed in 109 patients. T½ of perfusion peak, perfusion curve grades, and accumulation index (R20/3) were used as scintigraphic parameters. Baseline studies obtained within 48 hours after transplantation were evaluated for prediction of early graft dysfunction. All data were then assessed for specific diagnosis. Results Scintigraphic parameters were significantly higher in patients with delayed graft function (DGF) and slow graft function (SGF) than in patients with immediate graft function. These parameters in DGF were also considerably different from those in SGF. The mean RI was significantly high in DGF, but there was no difference between SGF and immediate graft function. In diagnostic groups, the mean values of all tests were significantly different between normal functioning grafts and pathological grafts (ATN + AR). There was no significant difference between AR and ATN. However, renal scintigraphy has higher sensitivity and specificity for AR as compared with RI of Doppler ultrasonography (US). Conclusions In predicting graft dysfunction and separating normal functioning graft from pathological graft (ATN + AR), renal scintigraphy provides more accurate information than Doppler US. Even though it is superior to Doppler US, renal scintigraphy also cannot reliably separate ATN from AR. The major advantage of renal scintigraphy is the early detection of reduced renal function.

Evaluation of Renal Transplant Scintigraphy and Resistance Index Performed Within 2 Days After Transplantation in Predicting Long-Term Graft Function.

Purpose Value of renal transplant scintigraphy and resistance index (RI) in the assessment of renal graft function is well known. The aim of this study was to evaluate the predictive value of renal transplant scintigraphy and RI for long-term graft function. Materials and Methods A total of 119 patients were analyzed retrospectively. Renal transplant scintigraphy with technetium Tc 99 m DTPA and color Doppler ultrasonography for RI were performed to each patient within 2 days after transplantation. Resistance index and the results of the tests in perfusion/renographic curve analysis of scintigraphy were compared with the serum creatinine (sCr) levels at 3 months, 1 year, and 5 years after transplantation. A sCr level of more than 1.5 mg/dL was considered abnormal. Results Differences of the mean values of T½ of graft washout (GW½), time difference between peak renal perfusion and arterial count ([INCREMENT]P), and accumulation index (R20/3) were significantly high in patients with high follow-up sCr (>1.5 mg/dL) (P < 0.01). The correlation of these tests with the follow-up sCr levels was significant (P < 0.01). The number of recipients with high perfusion curve grade was also significant in the follow-up groups with high sCr levels. However, difference of the mean value of RI was insignificant between the follow-up groups, and there was no correlation between the RI and sCr levels. Conclusion Renal transplant scintigraphy performed within 2 days after transplantation is useful in the prediction of long-term graft function at 3 months, 1 year, and 5 years; and it is superior to resistance index.

A New Quantitative Index for Baseline Renal Transplant Scintigraphy With 99mTc-DTPA in Evaluation of Delayed Graft Function and Prediction of 1-Year Graft Function.

Purpose The aims of this study were to assess quantitative indices of baseline renal transplant scintigraphy (RTS) with 99mTc-DTPA for evaluation of delayed graft function (DGF) and prediction of 1-year graft function and to describe a new inclusive index for RTS. Patients and Methods A total of 179 patients to whom RTS with 99mTc-DTPA was performed within 2 days after kidney transplantation were analyzed retrospectively. Hilson perfusion index, perfusion time (&Dgr;P), peak-to-plateau ratio, peak perfusion-to-iliac artery ratio, T½ of graft washout, peak perfusion-to-uptake ratio, and ratio of uptake at 20 to 3 minutes (R20/3) were obtained. In addition, we first described the following formula defined as graft index (GI): GI = (&Dgr;P × arterial peak × plateau)/(perfusion peak × uptake at 3 minutes). At 1 year, a serum creatinine level of more than 1.5 mg/dL was considered to be abnormal. Mann-Whitney U, Spearman coefficient of correlation test, and receiver operating characteristic curve were used for statistical analyses. P < 0.05 was considered statistically significant. Results Mean values of all the indices were significant. The most accurate, sensitive, and specific index for both identification of DGF and prediction of 1-year serum creatinine level of more than 1.5 mg/dL was GI. Area under the curve of GI was 0.94 for identification of DGF and 0.79 for 1-year prediction. Conclusions The question is, “Which index is the best indicator?” This study demonstrated that the parameters of &Dgr;P, plateau, arterial peak, perfusion peak, and uptake at 3 minutes of RTS could be assessed together by the formula of GI, which provides more accurate information to identify DGF and predict 1-year graft function.

18F-FDG and 18F-NaF PET/CT Findings of a Multiple Myeloma Patient With Thyroid Cartilage Involvement.

Thyroid cartilage is a very rare extramedullary involvement location in multiple myeloma. We present both F-NaF and F-FDG PET/CT findings of a multiple myeloma patient with thyroid cartilage involvement. In this patient, increased FDG and more intensely increased NaF uptake were seen on thyroid cartilage. In addition, some bone lesions had more intense NaF than FDG uptake, and some were only NaF avid. Although F-FDG PET/CT has an important role in plasma cell neoplasms, we considered that F-NaF PET/CT is also very useful to detect small lytic lesions that might be overlooked on F-FDG PET/CT.

Radioiodine uptake in an ovarian mature teratoma detected with SPECT/CT.

A 28-year-old woman underwent a near-total thyroidectomy for papillary carcinoma. Before radioiodine therapy, the serum thyroid-stimulating hormone level was 50 μIU/mL, the thyroglobulin level was 1 μg/L, and the antithyroglobulin was negative. She received 100 mCi of I for ablation of residual thyroid tissue. After therapy, I whole-body scan demonstrated focal uptake in the right pelvic area, which localized to the right ovary on SPECT/CT fusion images. The ovarian cyst was resected, and histopathological examination revealed a mature teratoma without thyroid tissue component. At 6-month follow-up, the whole-body radioiodine scan was normal, and serum thyroglobulin was undetectable.

Management of Childhood Thyroid Nodules: Surgical and Endocrinological Findings in a Large Group of Cases

Objective: The management of childhood thyroid nodules is still a big challenge for clinicians. In this study, we aimed to present our surgical and endocrinological experience in more than one hundred pediatric cases. Methods: A retrospective analysis of patients admitted with a thyroid nodule between 2006 and 2014 was performed. Detailed ultrasonography and fine-needle aspiration biopsy (FNAB) were the cornerstones of the diagnostic approach. Results: One hundred-three children (72 female, 31 male) with a mean age of 13.1±3.6 years (3-18 years) were admitted to our center. Management strategy was surgery in 58 patients and follow-up in 45 patients. Mean nodule size was 17±12.7 mm (2-45 mm). The diagnoses were listed as benign solitary nodule (48 patients), thyroid carcinoma (26 patients), multinodular goiter (23 patients), Hashimoto thyroiditis (4 patients), and Graves’ disease (2 patients). Surgical procedures were nodulectomy/lobectomy (32 patients), total thyroidectomy (TT) (13 patients), or TT+ neck dissection (13 patients). The rate of malignancy was 25% in the total group and 44% in the surgery group. The malignancy rate was higher in patients younger than 12 years compared to older children (41% vs. 17%, p=0.040). Metastasis was seen in 38% of the malignant nodules. Postoperative complications were transient hypocalcemia (8%), permanent hypocalcemia (1.7%), and unilateral vocal cord paralysis (1.7%). Recurrence or mortality was not encountered in the 5.4±1.2-year follow-up period. Conclusion: Thyroid nodule in a child requires an aggressive diagnostic approach due to increased risk of malignancy and metastasis. Intraoperative frozen section examination must be done as a useful adjunct to determine the surgical strategy. Incidence of complications is small in thyroid surgery when performed by experienced surgeons.

False-Positive 131I Uptake in a Benign Bone Lesion on Post-therapy Scan.

A 56-year-old woman underwent near-total thyroidectomy and papillary thyroid carcinoma without extrathyroidal extension was diagnosed. The serum thyroglobulin (Tg) level was 2.4 µg/L, and anti-Tg was negative when serum thyroid-stimulating hormone level was 85 µIU/mL. She received 100 mCi (3.7 GBq) of 131I. Besides the residual thyroid tissue, a focal uptake in the left clavicular bone was seen on posttherapy 131I images. Then, CT and MRI were performed to diagnosis. All imaging findings suggested that it was a benign bone cyst. At 6-month follow-up, the serum Tg level was undetectable with the thyroid-stimulating hormone level of more than 150 µIU/mL.

Value of SPECT/CT in Cervical Vertebra Metastasis Mimicking Residual Thyroid Tissue on Planar I-131 Scan

A total thyroidectomy was performed on a 62 year-old male patient with 3.5 cm cold nodule and diagnosis of differentiated thyroid carcinoma was made. He received 200 mCi of I-131 because pulmonary metastases were founded on computed tomography and his serum thyroglobulin level was high (>300 ng/ml). Post-therapy planar whole body scan showed diffuse pulmonary tracer accumulation consistent with pulmonary metastases, 3 foci of activities in the thyroid region of neck and physiological tracer uptake in the liver. Initially, it was considered that high serum thyroglobulin level was caused by pulmonary metastases and activities in the neck were due to residual thyroid tissue. But, single photon emission computed tomography/computed tomography (SPECT/CT) images demonstrated that the activity in the midline of the neck was originated in the cervical (C5-6) vertebra due to bone metastasis. Cervical vertebra metastasis in the same level with probable residual thyroid tissue in planar I-131 whole body scan can be easily overlooked. We considered that the complementary SPECT/CT for head and neck region should be used not only in the selected differentiated thyroid patients with unexpected abnormal activity but also in patients with expected residual thyroid tissue, salivary gland or mouth activity in planar I-131 whole body scan.

Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Objective: Radioiodine is the most specific radionuclide for differentiated thyroid carcinoma (DTC) imaging. Despite its high specificity and sensitivity, false-positive I-131 uptake could be seen on whole body scan (WBS) that may lead to misdiagnosis and unnecessary radioiodine treatment. In this study, we aimed to present the I-131 WBS and concomitant single photon emission computed tomography/computed tomography (SPECT/CT) images of unexpected false-positive radioiodine uptake along with the patients’ clinical outcomes and the contribution of SPECT/CT imaging. Methods: I-131 WBSs of 1507 patients with DTC were retrospectively reviewed, and anticipated I-131 uptakes (like in breasts or thymus) were excluded from the study. The unexpected false-positive I-131 uptakes with concomitant SPECT/CT imaging were included in the study. Results: Twenty-one patients had 23 unexpected I-131 uptakes on WBS and concomitant SPECT/CT imaging. The vast majority (87%) of these cases were seen on post-therapeutic I-131 WBS. Most of the false-positive I-131 uptakes could be explained by SPECT/CT and radiologic findings, and were secondary to non-thyroid conditions (bronchiectasis, lung infection, subcutaneous injection into gluteal fatty tissue, aortic calcification, benign bone cyst, vertebral hemangioma, recent non-thyroid surgical procedure site, rotator cuff injury, mature cystic teratoma and ovarian follicle cyst). However, the possible reasons of 9 false-positive I-131 uptakes could not be explained by radiologic findings. Conclusion: We suggest that false-positive I-131 uptake and its underlying mechanisms (inflammation, trapping, increased perfusion, etc.) must be kept in mind in patients with thyroid cancer and unexpected findings must be considered together with serum thyroglobulin levels, SPECT/CT and radiologic findings in order to avoid misdiagnosis and unnecessary radioiodine treatment.