The variation of quantitative parameters and Deauville scores with different reconstruction algorithms in FDG PET/CT imaging of lymphoma patients.

INTRODUCTION AND OBJECTIVES: 18F-FDG PET with the Deauville score (DS) is a unique semiquantitative method for lymphoma. However, type of standard uptake values (max, mean, and peak) reconstruction algorithms could affect DS. We compared the Bayesian Penalized Likelihood reconstruction algorithm (BPL) with Ordered Subsets Expectation Maximization (OSEM) on quantitative parameters and DS in lymphoma. We investigated the effect of the size of the lymph node on quantitative variation. PATIENTS AND METHODS: Raw PET data of 255 lymphoma patients were reconstructed separately with Q.Clear (GE Healthcare), a BPL, and SharpIR (GE Healthcare), an OSEM algorithm. In both images, each patient's liver, mediastinal blood pool, and SUVs (SUVmax, SUVmean, and SUVpeak) of a total of 487 lesions selected from the patients were performed. DSmax, DSmean, and DSpeak were compared. RESULTS: In our study, DS increased significantly with BPL (p < 0.001), and the DS increased to 4-5 in thirty patients evaluated as 1-2-3 with OSEM. It was found that the quantitative values of the lymph nodes increased statistically with BPL (p < 0.001), and the liver from the reference regions were significantly decreased (p < 0.001). In addition, difference in lymph node was independently associated with size of lesion and was significantly more pronounced in small lesions (p < 0.001). The effects of BPL algorithm were more pronounced in SUVmax than in SUVmean and SUVpeak. DS-mean and DS-peak scores were less changed by BPL than DS-max. CONCLUSION: Different reconstruction algorithms in FDG PET/CT affect the quantitative evaluation. That variation may affect the change in DS in lymphoma patients, thus affecting patient management.

Incidental Spleen Cyst Mimicking Thyroid Carcinoma Metastasis: False-positive Uptake on Radioiodine Whole Body Scan.

In differentiated thyroid cancer, radioiodine therapy and whole body scans (WBS) are integral part of disease management. We present the case of a 33-year-old woman with multifocal thyroid carcinoma who was treated with radioiodine. Post-treatment WBS scintigraphy showed focal increased I-131 uptake in the spleen, although stimulated thyroglobulin level was not suggestive of distant metastasis. Dynamic magnetic resonance imaging performed later revealed that the finding was an incidental splenic cyst. Radioiodine uptake is not specific to the thyroid tissue. Benign pathologies showing increased radioiodine uptake should be considered in cases with splenic radioiodine accumulation in WBSs.

Rheumatology experience with FDG PET / CT in inflammation of unknown origin: a single - centre report for determining factors associated with diagnostic precision.

BACKGROUND / AIM: The use of PET / CT is becoming more common in the elucidation of inflammatory processes in which the underlying cause cannot be determined by conventional examinations. Although PET / CT is an effective method for detecting inflammatory foci, the precise diagnosis may not be obtained in all cases. In addition, considering factors such as radiation exposure and cost, it becomes important to identify patients who can get results with PET / CT. In this study, it was aimed to examine the factors that can predict the differential diagnostic value of PET / CT by retrospectively scanning patients who underwent PET / CT for inflammation of unknown origin (IUO) in rheumatology practice. METHODS: Demographic, clinical and laboratory information of the patients followed up in our clinic and who underwent PET / CT for differential diagnosis were enrolled. Whether they were diagnosed after PET / CT and during the follow - up period, and their diagnoses were examined. RESULTS: A total of 132 patients were included in the study. A previous diagnosis of rheumatic disease was present in 28.8 % of the patients, and a history of malignancy was present in 2.3 % . The patients were divided into three groups: group 1 patients with increased FDG uptake in PET / CT and diagnosis confirmed by PET / CT, group 2 patients with increased FDG uptake in PET / CT but diagnosis was not confirmed, and group 3 patients without increased FDG uptake in PET / CT. Increased FDG uptake in PET / CT was detected in 73 % of the patients. While PET / CT helped the diagnosis in 47 (35.6 %) patients (group 1), it did not help the diagnosis in 85 (64.4 %) (groups 2 and 3). Thirty - one (65.9 %) of the diagnosed patients were diagnosed with a rheumatologic disease. When the 3 groups were compared, male gender, advanced age, CRP levels, presence of constitutional symptoms, SUVmax values and number of different organs with increased FDG uptake were higher in Group 1. Sixty - six percent and 74 % of the patients in groups 2 and 3 were not diagnosed during the follow - up period. No patient in group 3 was diagnosed with malignancy during follow - up. CONCLUSION: PET / CT has high diagnostic value when combined with clinical and laboratory data in the diagnosis of IUO. Our study revealed that various factors can affect the diagnostic value of PET / CT. Similar to the literature, the statistically significant difference in CRP levels shows that patients with high CRP levels are more likely to be diagnosed with an aetiology in PET / CT. Although detection of involvement in PET / CT is not always diagnostic, there was an important finding that no malignancy was detected in the follow - up in any patient without PET / CT involvement. Key points • PET / CT is an effective method for detecting inflammatory foci. • PET / CT has proven to be effective in the diagnosis of rheumatological diseases, the extent of disease and the evaluation of response to treatment. • Indications for the use of PET / CT in the field of rheumatology and the associated factors and clinical features supporting the diagnosis with PET / CT are still to be fully clarified. • In routine practice, with PET / CT, both delays in diagnosis and examinations performed during diagnosis and the cost can be reduced.

The impact of 18F-fluorodeoxyglucose PET/computed tomography on clinical staging in bladder cancer.

AIM: To determine the impact of 18F-FDG PET/computed tomography (CT) on clinical staging in bladder cancer with comparison to conventional CT and MRI. METHODS: A total of 142 patients who underwent 18F-FDG PET/CT imaging with a diagnosis of bladder cancer between 1 June 2019 and 31 December 2020 were screened retrospectively. Seventy patients who underwent diagnostic CT or MRI within 2 months before or after PET/CT were included in the study. The N and M stages determined by CT, MRI and PET/CT according to the eighth version of the TNM staging system were recorded. T-test was used to determine the levels of significant difference, and univariate logistic regression analysis was used to evaluate the impact of the T stage on nodal up-staging. RESULTS: According to the PET/CT, the N stage increased in 19 patients (27.14%) and decreased in seven patients (10%). Likewise, the M stage increased in 16 patients (22.86%) and decreased in seven patients (10%). The N stage determined by PET/CT was confirmed by pathologic examination in all cases in which the two modalities were inconsistent. In muscle-invasive cases, the rate of increase in the N stage after PET/CT (36.95%) was found to be significantly higher than in that of cases without invasion (8.33%) (P = 0.011). Increasing T stage was associated with an increase in the N stage after PET/CT (odds ratio: 2.33, 95% confidence interval: 1.02-5.28, P = 0.042). CONCLUSION: 18F-FDG PET/CT can potentially change the clinical stage determined by CT and MRI when used for staging in bladder cancer, and can lead to nodal up-staging particularly in cases with muscle-invasive bladder cancer.

Comparison of 99mTc-MIBI planar scintigraphy, SPET/CT and ultrasonography in detection of parathyroid adenoma in patients with primary hyperparathyroidism.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is a common endocrine disease that is caused by a single adenoma in most of the cases. Surgical management is the mainstay and definitive treatment for parathyroid adenoma (PA). Minimally invasive surgical techniques are as effective as bilateral neck exploration with a lower risk of complications and better cosmetic results in patients with solitary PA. Accurate preoperative localization with imaging modalities is paramount for determining patients candidate for minimally invasive surgery. In this study we aimed to evaluate the diagnostic performance of technetium-99m-methoxyisobutylisonitrile ( 99mTc-MIBI) planar scintigraphy (PS), single photon emission tomography/computed tomography (SPET/CT) and ultrasonography (US) in patients with PHPT. MATERIAL AND METHODS: Fifty-eight patients with biochemical evidence of PHPT who underwent pre-operative imaging with parathyroid scintigraphy and US for detection and localization of PA and proceeded to surgery were included in the study. All patients underwent dual phase 99mTc-sesta MIBI parathyroid scintigraphy (early and delayed planar images and delayed SPET/CT). Data analysis was performed to evaluate the sensitivity, specificity, diagnostic accuracy and PPV of planar images, SPET/CT and US alone and combined US and SPET/CT. Histopathology was used as gold standard. RESULTS: Sensitivity, specificity, PPV and diagnostic accuracy for detection of PA, 80,4%, 42,8%, 91,1% and 75,8% for PS; 80,4%, 57,7%, 91,1% and 77,5% for delayed SPET/CT; 88,2%, 85,7%, 97,8% and 87,9% for US and 94,1%, 71,4%, 96% and 91,3% for SPET/CT+US. Combined US and SPET/CT has been shown to increase sensitivity and diagnostic accuracy. The overall sensitivity of PS and SPET/CT didn't vary however additional information which is helpful for planning minimally invasive surgery gained from tomographic images. CONCLUSION: The combined use of US and SPET/CT has incremental value in accurately localizing PA over either technique alone. In the preoperative assessment of patients with PHPT combination of imaging methods allows selection of patients who would be suitable for minimally invasive surgery.

The results of nasopharyngeal cancer patients treated by simultaneous integrated boost technique and concomitant chemotherapy

Background/aim: To assess the efficacy and side effects of concurrent weekly chemotherapy and radiotherapy with simultaneous integrated boost (SIB) technique for nasopharyngeal cancer (NPC). Materials and methods: total of 51 consecutive patients with diagnosis of NPC were treated between February 2010 and December 2015. The median dose for PTV70 (range: 60­82) was given in 33 fractions (range: 31­35). Forty-five of the patients received concomitant weekly chemotherapy between 3­7 cycles (median 6). Eleven patients received neoadjuvant and thirty-nine patients received adjuvant chemotherapy. Results: At a median follow-up 43 months (range: 2­76) the estimated 5-year overall survival and disease-free survival were 74.6% and 62.6%, respectively. Conclusion: In radiotherapy of advanced NPC, generally a considerable amount of normal head and neck tissues might have to be irradiated in addition to gross tumor volume, involved node, and elective neck irradiation. Together with chemoradiotherapy, poor oral hygiene and inadequate nutritional support result in excessive morbidity. Despite loco-regional success of concurrent chemoradiotherapy, distant metastasis is still the major pattern of treatment failure in the intensity modulated radiotherapy era. We need to improve our adjuvant chemotherapy regimens or develop new drugs.

The diagnostic value of parathyroid hormone washout in primary hyperparathyroidism patients with negative or equivocal 99 m Tc-MIBI results.

BACKGROUND AND OBJECTIVES: The accurate identification of hyper functioning parathyroid gland is needed for definitive surgical treatment in primary hyperparathyroidism. Ultrasonography and 99mTechnetium sestamibi scintigraphy are the two most used methods with varying sensitivities. This study aimed to assess the value of parathyroid hormone (PTH) assay in preoperative ultrasound guided fine needle aspiration (FNA)-PTH washout fluid to verify the correct localisation of lesions with negative or inconclusive scintigraphy results. METHODS: We evaluated data of 28 lesions in 21 patients who underwent US-guided parathyroid fine-needle aspiration (FNA) with PTH washout, retrospectively. The PTH washout results and the reports of parathyroid surgery and imaging studies were reviewed. RESULTS: Of operated 28 lesions 23 had positive and 5 had negative washout results. The median FNA-PTH washout was 2315.5 pg/ ml (min-max: 12.3-6978 pg/ ml). The calculated sensitivity of FNA-PTH washout was 85.7% and the specifity was 28.6%. The positive and negative predictive values were 78.3% and 40.0%, respectively. CONCLUSIONS: FNA-PTH can be used to establish the nature of the lesion, discriminate parathyroid gland from thyroid lesions or cervical lymph nodes, improving the surgical outcomes. It can be used to localise parathyroid lesions preoperatively when negative or discordant ultrasound and scintigraphy findings are obtained.

Determination of structural femoral head allograft viability and integrity with a novel diagnostic tool: SPECT/CT. A preliminary study.

OBJECTIVE: To evaluate the viability and integrity of fresh frozen bulk femoral head allografts obtained from the institutional bone bank that were used to reconstruct severe acetabular defects and to validate the SPECT/CT method which gives both anatomical and functional data for this purpose. METHODS: We retrospectively reviewed 9 patients (6 female, 3 male; mean age 63.6 years). Preoperative and postoperative leg lengths, existence of the Trendelenburg sign, range of motion of the hip, visual analogue score (VAS), Harris Hip Score (HHS) and any complication were assesed at each follow-up. Radiographically, position of the cup, signs of loosening or migration, and union of the graft were all determined. At the latest follow-up, patients were evaluated with hybrid SPECT/CT. RESULTS: The average duration of follow-up was 38.1 months (24-50 months). The overall mean HHS and VAS scores were significantly improved (p<0.05). When hybrid SPECT/CT results were evaluated, the vascular phase of scintigraphy showed hyperaemia of the graft and the bone phase of scintigraphy showed normal or increased radiotracer uptake in the graft site in 7 patients. SPECT/CT images were used to determine the exact localisation of osteoblastic activity. 1 patient with minor resorption of the graft without clinical symptoms revealed mild osteoblastic activity. The patient who had no activity in the graft site was rerevised because of infection. CONCLUSIONS: Institutional bank allografts are still excellent options for treating large acetabular defects in revision total hip arthroplasty where trabecular metals are not available or in common use. The Hybrid SPECT/CT method is a reliable, noninvasive method for evaluating both the integrity and viability of a bulk graft in 3-D.

Prognostic Significance of Standardized Uptake Value on 18Fluorine-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients with Nasopharyngeal Carcinoma.

The aim of this study was to investigate the prognostic significance of standardized uptake value (SUV) on 18 fluorine-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) in patients with nasopharyngeal carcinoma (NPC). Thirty-four patients who have histologically proven NPC and underwent 18F-FDG PET/CT were included in this study. After 18F-FDG PET/CT, all the patients received radiation therapy and 32 of them received concomitant weekly chemotherapy. The maximum SUV (SUVmax) at the primary tumor and the SUVmaxof the highest neck nodes were determined. The SUVmax-T ranged from 5.00 to 30.80 (mean: 15.37 ± 6.10) and there was no difference between SUVmax-T values for early and late stages (P = 0.99). The SUVmax-N ranged from 3.10 to 23.80 (mean: 13.23 ± 5.76). There was no correlation between SUVmax-T and SUVmax-N (r = 0.111, P = 0.532). There was no difference between the SUVmax-T and the positivity of neck lymph nodes (P = 0.169). The ability of SUVmaks-N to predict stage was obtained by a receiver operating characteristic (ROC) analysis. The area under the curve is 0.856 and the best cut-off value is 7.88. There was a good correlation between SUVmax-N and stage. While the mean SUVmax-T for the alive patients was slightly lower than that for the dead (14.65 ± 5.58 vs. 20.30 ± 7.92, P = 0.061), the difference between the groups was not statistically significant. Furthermore, there was no statistically significant difference for SUVmax-N between these two groups (P: 0.494). Cox-regression analysis showed that an increase in SUVmax-T and SUVmax-N was associated with death risk (relative risk [RR]: 1.13, P = 0.078 and RR: 1.052, P = 0.456, respectively). SUVmax-T and SUVmax-N were independent prognostic factors for survival in NPC patients. This will help the clinicians in choosing suitable candidates for more aggressive treatment modalities.

Hypocalcemia development in patients operated for primary hyperparathyroidism: Can it be predicted preoperatively?

OBJECTIVE: Primary hyperparathyroidism (PHP) is a common endocrine disease, and its most effective treatment is surgery. Postoperative hypocalcemia is a morbidity of parathyroid surgeries, and it may extend hospitalization durations. The purpose of this study is to determine the predictive factors related to the development of hypocalcemia and hungry bone syndrome (HBS) in patients who underwent parathyroidectomy for PHP. MATERIALS AND METHODS: Laboratory data comprising parathyroid hormone (PTH), calcium, phosphate, 25-OHD, albumin, magnesium, alkaline phosphatase (ALP), blood urea nitrogen (BUN), and thyroid stimulating hormone (TSH) of the patients were recorded preoperatively, on the 1st and 4th days postoperatively, and in the 6th postoperative month, and their neck ultrasound (US) and bone densitometry data were also recorded. RESULTS: Hypocalcemia was seen in 63 patients (38.4%) on the 1st day after parathyroidectomy. Ten patients (6.1%) had permanent hypocalcemia in the 6th month after surgery. Out of the patients who underwent parathyroidectomy for PHP, 22 (13.4%) had HBS. The incidence of postoperative hypocalcemia was higher in patients who underwent parathyroidectomy for PHP, who had parathyroid hyperplasia, and who had osteoporosis. Preoperative PTH, ALP, and BUN values were higher in those patients who developed HBS. Furthermore, HBS was more common in patients who had osteoporosis, who had parathyroid hyperplasia, and who underwent thyroidectomy simultaneously with parathyroidectomy. CONCLUSIONS: As a result, patients who have the risk factors for development of hypocalcemia and HBS should be monitored more attentively during the perioperative period.

A case of sarcoidosis diagnosed by positron emission tomography/computed tomography.

Sarcoidosis is a multisystem granulomatous disorder of unknown cause which may affect any organ or system but primarily involve the lungs and the lymphatic system. Extrapulmonary sarcoidosis represents approximately 30-50% of patients. We report the case of a 51-year-old female who presented with increasing complaints of a cough, weakness, weight loss, and chest pain and who was found to have a suspicious lesion on thorax computed tomography(CT). Fluorodeoxyglucose (FDG) positron emission tomography/CT performed for diagnostic purposes demonstrated increased FDG accumulation at the bilateral enlarged parotid and lacrimal gland and in the reticulonodular infiltration area located in the left lung as well as multiple lymphadenopathies with increased FDG accumulation. There were also hepatosplenomegaly and splenic uptake. Skin biopsy showed noncaseating granulomas, and the patient was diagnosed as stage 2 sarcoidosis.

Evaluation of Silent Myocardial Ischemia with Single-Photon Emission Computed Tomography/Computed Tomography in Asymptomatic Subjects with Diabetes and Pre-Diabetes.

OBJECTIVE: The aim of this study was to disclose the prevalence of myocardial ischemia, as detected by adenosine stress myocardial perfusion imaging (MPI) with hybrid single-photon emission computed tomography/computed tomography (SPECT/CT), in asymptomatic diabetic and pre-diabetic patients and to find out whether ischemia predicted the occurrence of adverse cardiac/cerebrovascular events (ACCE) at follow-up. METHODS: Forty-three diabetic and thirty-five pre-diabetic asymptomatic patients without any history of coronary artery disease, underwent MPI and were followed-up for a 12.8±2.2 (8-19) months for the occurrence of ACCE. Baseline variables that would predict the presence of ischemia and the value of ischemia on MPI for predicting the occurrence of ACCE at follow-up were evaluated by logistic regression analysis. RESULTS: Ischemia was detected in ten (23.3%) of the diabetic and in four (11.4%) of the pre-diabetic patients. The presence of diabetes was the only independent predictor of myocardial ischemia [odds ratio (OR): 12.31, 95% confidence interval (CI): 1.83-82.66; p<0.01]. During 12.8±2.2 (8-19) months of follow-up, ACCE was observed in five out of 78 (6.4%) patients. Patients with ischemia were significantly more likely to have ACCE during follow-up as compared to those with normal MPI scans (event rates: 21.4% vs. 3.1%, OR: 8.455 95% CI: 1.264-56.562, p=0.038). CONCLUSION: Myocardial ischemia as detected by adenosine stress SPECT/CT in a population of asymptomatic patients with diabetes mellitus or pre-diabetes appeared to predict the occurrence of ACCE at follow-up.

The role of postoperative Tc-99m pertechnetate scintigraphy in estimation of remnant mass and prediction of successful ablation in patients with differentiated thyroid cancer.

OBJECTIVE: Surgery and radioactive iodine (RAI) ablation constitute the mainstay of the treatment of differentiated thyroid carcinoma (DTC). In this study, we aimed to evaluate the diagnostic value of postoperative early Tc-99m pertechnetate scanning to detect remnant thyroid tissue and predict ablation success. METHODS: DTC patients evaluated with postoperative Tc-99m pertechnetate scintigraphy and treated with RAI between January 2007 and December 2014 were recruited. The results of Tc-99m pertechnetate scanning were compared with therapeutic I-131 whole-body scanning (TxWBS) and diagnostic I-131 whole-body scanning (DxWBS) performed 6-9 months after RAI. RESULTS: There were 154 (21.5%) male and 563 (78.5%) female patients, with a mean age of 49.11±12.35 years. Postoperative Tc-99m pertechnetate scanning was positive in 499 patients (69.6%) and negative in 218 (30.4%) patients. There were 673 (93.9%) patients with a positive TxWBS scan and 44 (6.1%) patients with negative TxWBS scan. Considering TxWBS as the standard test, sensitivity, specificity, positive predictive value, and negative predictive value of Tc-99m pertechnetate scanning were 72.2, 70.5, 97.4, and 14.2%, respectively. DxWBS was positive in 57 (9.0%) and negative in 564 (91%) patients. Ablation dose was higher and preablation thyroglobulin was lower in patients with negative DxWBS (P=0.001 and 0.04, respectively). Overall, 171 (92.9%) of 184 patients with negative Tc-99m pertechnetate had negative DxWBS. CONCLUSION: Postoperative Tc-99m pertechnetate scintigraphy has a high positive predictive value to detect remnant tissue in patients with DTC. Although negative Tc-99m pertechnetate scanning does not indicate removal of all thyroid tissue, it is related to successful ablation in more than 90% of patients.

A new approach for standardization and increased accuracy of lymph node washout thyroglobulin in patients with differentiated thyroid carcinoma.

BACKGROUND: High values of fine needle aspiration washout thyroglobulin (FNAB-Tg) are diagnostic for metastatic lesions of thyroid cancer. However, there is not a consensus on cutoff for high FNAB-Tg level. In this study, we aimed to determine a more accurate and standardized parameter for FNAB-Tg. METHODS: Ultrasonographically suspicious lymph nodes of patients with histopathologically confirmed differentiated thyroid cancer or malignant/suspicion for malignancy cytology were included. Tg washout was obtained by aspiration and nonaspiration fine needle biopsy (nonaspiration-FNB). Simultaneous Tg was measured from serum. Aspiration and washout procedures were also performed from whole blood and serum using syringes and needles identical to ones used for lymph node biopsy. RESULTS: Data of 19 lesions in 17 patients who underwent lymph node dissection were analyzed. Nonaspiration FNB-Tg, FNAB-Tg/whole blood washout-Tg, nonaspiration FNB-Tg/whole blood washout-Tg, nonaspiration FNB-Tg/serum washout-Tg, nonaspiration FNB-Tg/serum Tg ratios were significantly higher in malignant lymph nodes compared to benign ones. Areas under the ROC curve for nonaspiration FNB-Tg, FNAB-Tg/whole blood washout-Tg, FNAB-Tg/serum washout-Tg, nonaspiration FNB-Tg/whole blood washout-Tg, nonaspiration FNB-Tg/serum washout-Tg, and nonaspiration FNB-Tg/serum Tg were statistically significant for the discrimination of benign and malignant lymph nodes. Best cutoff value for nonaspiration FNB-Tg was 4.21. Among ratios, best cutoff values were 5.40 for nonaspiration FNB-Tg/whole blood washout-Tg and 3.28 for nonaspiration FNB-Tg/serum washout-Tg. CONCLUSION: For detection of malignant lymph nodes, determining ratios of nonaspiration FNB-Tg to whole blood and/or serum washout-Tg might be a promising method to increase accuracy and provide standardization of lymph node washout procedure.

The evaluation of hypermetabolic mediastinal-hilar lymph nodes determined by PET/CT in pulmonary and extrapulmonary malignancies: correlation with EBUS-TBNA.

BACKGROUND/AIM: We aimed to define the optimal SUV(max) cut-off value in determination of mediastinal-hilar lymph node metastasis, by comparing positive PET/CT results with the results of endobronchial ultrasound guided transbronchial needle aspiration biopsy (EBUS-TBNA). MATERIALS AND METHODS: Thirty-one patients with malignancy whose PET/CT imaging revealed a hypermetabolic mediastinal and/or hilar lymph node and who had undergone EBUS-TBNA were evaluated retrospectively. Histopathology was regarded as the gold standard. The diagnostic role of PET/CT in mediastinal/hilar lymph node metastasis was investigated and compared with the results of contrast-enhanced CT. RESULTS: When a SUV(max) value of 2.5 was used, the sensitivity, positive predictive value (PPV), and diagnostic accuracy of the PET/CT were 100%, 65.4%, and 65.4% respectively. In the ROC analysis, the SUV(max) cut-off value with the highest diagnostic accuracy (75%) was calculated as 6.3, and when this value was considered, the sensitivity, specificity, PPV, negative predictive value, and diagnostic accuracy of the PET/CT were determined as 70.6%, 83.3%, 88.9%, 60%, and 75% respectively (AUC: 0.779). The sensitivity, PPV, and diagnostic accuracy of the thorax CT were calculated as 91.1%, 72%, and 71.1%, respectively. CONCLUSION: When determining mediastinal-hilar lymph node metastasis via PET/CT, although a SUV(max) cut-off value of 6.3 increases specificity and diagnostic accuracy, we think that a SUV(max) cut-off value of 2.5 and above give more optimal results in routine practice.

PET/CT findings in a case with FDG-avid disseminated lacrimal gland MALToma with sequential development of large B-cell lymphoma and gastric MALToma.

Primary orbital lymphomas are rare; the major histopathologic type is extranodal marginal-zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) or MALToma. We present a case of a 79-year-old female patient with FDG-avid lacrimal gland MALToma with nodal and pulmonary involvement (stage IVE). Nasopharynx and gastric involvement were detected on restaging F-FDG PET/CT after rituximab therapy, and it was found to have a site of transformation to diffuse large B-cell lymphoma (DLBCL) in the nasopharynx. Gastric MALT lymphoma was also confirmed histopathologically, and she then underwent combination chemotherapy regimen, resulting in regression after 3 courses.

Predictors and Diagnostic Significance of the Adenosine Related Side Effects on Myocardial Perfusion SPECT/CT Imaging.

OBJECTIVE: The aim of this study was to investigate the relationship between patient characteristics and adenosine-related side-effects during stress myocard perfusion imaging (MPI). The effect of presence of adenosine-related side-effects on the diagnostic value of MPI with integrated SPECT/CT system for coronary artery disease (CAD), was also assessed in this study. METHODS: Total of 281 patients (109 M, 172 F; mean age:62.6±10) who underwent standard adenosine stress protocol for MPI, were included in this study. All symptoms during adenosine infusion were scored according to the severity and duration. For the estimation of diagnostic value of adenosine MPI with integrated SPECT/CT system, coronary angiography (CAG) or clinical follow-up were used as gold standard. RESULTS: Total of 173 patients (61.6%) experienced adenosine-related side-effects (group 1); flushing, dyspnea, and chest pain were the most common. Other 108 patients completed pharmacologic stress (PS) test without any side-effects (group 2). Test tolerability were similar in the patients with cardiovascular or airway disease to others, however dyspnea were observed significantly more common in patients with mild airway disease. Body mass index (BMI) ≥30 kg/m2 and age ≤45 years were independent predictors of side-effects. The diagnostic value of MPI was similar in both groups. Sensitivity of adenosine MPI SPECT/CT was calculated to be 86%, specificity was 94% and diagnostic accuracy was 92% for diagnosis of CAD. CONCLUSION: Adenosine MPI is a feasible and well tolerated method in patients who are not suitable for exercise stress test as well as patients with cardiopulmonary disease. However age ≤45 years and BMI ≥30 kg/m2 are the positive predictors of adenosine-related side-effects, the diagnostic value of adenosine MPI SPECT/CT is not affected by the presence of adenosine related side-effects.

Hot-clot artifacts in the lung parenchyma on F-18 fluorodeoxyglucose positron emission tomography/CT due to faulty injection techniques: two case reports.

F-18-fluorodeoxyglucose (FDG) positron emission tomography/CT is an important whole-body imaging tool in the oncology and widely utilized to stage and restage various malignancies. The findings of significant focal accumulation of FDG in the lung parenchyma in the absence of corresponding CT abnormalities are related to the lung microembolism and known as hot-clot artifacts. Herein we present two cases with focal FDG uptake in the lung parenchyma with no structural lesions on the CT scan and discuss the possible mechanisms.

Predictive role of nontumoral sodium iodide symporter activity and preoperative thyroid characteristics in remission process of thyroid cancer patients.

OBJECTIVE: The target of radioiodine ablation therapy (RIAT) after complete tumor removal is the nontumoral remnant tissue. We aimed to evaluate sodium iodide symporter (NIS) expression in nontumoral thyroid tissue in differentiated thyroid cancer (DTC) patients who have complete but delayed structural response (DSR) to RIAT after surgery. Preoperative thyroid characteristics such as volume and nontumoral histology were also investigated for both DSR and its control group as potential predictors of insufficient NIS activity in this study. METHODS: Total of 600 patients with postoperative remnant thyroid tissue and who were in remission after RIAT spontaneously, were included in the study. Patients with positive diagnostic whole body scan (DxWBS) with thyroid bed uptake and stimulated serum Tg level <2 ng/mL at first year visit after initial therapy were defined as DSR group. Immunohistochemical staining of NIS protein was performed on the nontumoral tissue sections from surgery and semi quantified in terms of density and intensity. DSR and its control group were also compared in terms of NIS expression, radioiodine (RAI) uptake on post-therapy scan and preoperative thyroid characteristics. RESULTS: When compared with the control group, the density and intensity of NIS expression as well as the intensity of RAI uptake were significantly lower in DSR group (p = 0.001). There were also significant differences between groups regarding preoperative thyroid characteristics; i.e. preoperative thyroid volumes were significantly higher and the presence of concurrent benign thyroid disease was significantly more common in DSR group (p = 0.035, p = 0.001). Hashimoto thyroiditis was 8.59 times higher (95% CI; 2.31-31.96) and multinodular goiter was 7.50 times higher (95% CI; 1.88-29.91) among DSR group when compared with the control group. CONCLUSIONS: Our findings suggest that insufficient NIS activity in nontumoral thyroid tissue associates with DSR in DTC patients who have postoperative remnant tissue. Preoperative thyroid characteristics such as volume and concomitant benign thyroid disease may have an important role in predicting the complete response time to RIAT in these patients.