18F-FDG PET/CT and 99mTc-MDP Bone Scintigraphy Findings of Multifocal Desmoid Fibromatosis.

ABSTRACT: Desmoid fibromatosis, also called desmoid tumors, is a group of locally aggressive fibromatous proliferative disorders. They represent less than 3% of all soft tissue sarcoma and are multifocal in approximately 10% of cases. However, there are only a few cases in the literature describing 18F-FDG PET/CT and 99mTc-MDP bone scan features of extra-abdominal desmoid fibromas, and all were solitary bone lesions. Herein, we presented a unique case of multifocal desmoid fibromatosis of bone illustrating the prospective value of 18F-FDG PET/CT and 99mTc-MDP bone scan in the evaluation of desmoid tumors.

Evaluating therapeutic efficacy of extended shelf-life 90 Y glass microspheres in transarterial radioembolization for colorectal cancer: a quantitative FDG PET/CT analysis.

OBJECTIVES: There is a lack of sufficient evidence regarding the use of extended shelf-life (ExSL) Yttrium-90 ( 90 Y) glass radiomicrospheres in metastatic colorectal cancer (mCRC) patients. We aimed to investigate the efficacy of ExSL 90 Y glass radiomicrospheres with a personalized treatment approach by analyzing 18 F-FDG PET/CT quantitative parameters [metabolic tumor volume (MTV) and total lesion glycolysis (TLG)] separately before and after the treatment. METHODS: A total of 93 radioembolization sessions involving 77 patients were included. Simplicit 90 Y software was utilized to perform multicompartmental voxel-based dosimetry. Adverse events were recorded using the CTCAE v5.0 criteria. The survival data were recorded in detail. RESULTS: The overall disease control rate was 84.9%, with a median overall survival (OS) of 12.7 months and median progression-free survival (PFS) of 8.3 months. A statistically significant increase in treatment response rate was observed when there was an increase in absorbed tumor dose for pre-treatment unit MTV ( P  = 0.005) and TLG ( P  = 0.004) values. We didn't observe any additional side effects/vital risks that could be considered clinically significant. CONCLUSION: Our study has provided evidence on the therapeutic effectiveness and safety in terms of dose-toxicity profile of ExSL 90 Y glass microspheres in a large cohort of mCRC patients. With a personalized treatment approach, the increase in radiation dose absorbed by the tumor has shown a significant contribution to treatment response rate, as indicated by quantitative measurements obtained through 18 F-FDG PET/CT.

"Wandering Spleen" With Lymphomatous Involvement.

ABSTRACT: Wandering spleen is a rare condition caused by either lack or the laxity of ligaments, which results malposition in the lower abdomen or pelvis. FDG PET/CT is the cornerstone of the staging procedures in the management of lymphomas leading to upstaging and picking up occult lesions in the spleen and extranodal sites. Herein, we reported initial staging 18 F-FDG PET/CT findings of a woman with Hodgkin lymphoma whose spleen was absent in normal position and multiple intense heterogenous hypermetabolism in a pelvic mass raised a suspicion of wandering splenic involvement. The confirmation was made with selective spleen SPECT/CT images thereafter.

Disseminated Nocardia farcinica Infection and Treatment Response on F-18 Fludeoxyglucose Positron Emission Tomography Computed Tomography.

We report a rare case of nocardiosis with increased F-18 Fludeoxyglucose (F-18 FDG) uptake in widespread abscess foci of Nocardia farcinica infection in an immunocompromised patient on positron emission tomography computed tomography (PET/CT) imaging. A relatively infrequent cause of nocardiosis, N. farcinica is an opportunistic infection that may present with clinically aggressive disseminated disease. Whole-body F-18 FDG-PET/CT allows identifying the extent of disease, as well as monitoring response to therapy in patients with nocardiosis especially the disseminated form.

Effect of Anticoagulants in Pulmonary Thromboembolism in Post-COVID-19 Patients.

Background and objective COVID-19 may predispose to both venous and arterial thromboembolism (VTE and ATE) due to excessive inflammation, immobilization, and hypoxia. The purpose of this study is to evaluate clinical and laboratory risk factors, as well as related medications such as anticoagulants, to predict the risk of thromboembolic disease and/or death in COVID-19 patients. Methods Over a period of 14 months (from August 2020 to September 2021), a total of 145 consecutive patients with signs and symptoms suspicious of pulmonary embolism (PE) were referred for perfusion single-photon emission computed tomography/computed tomography (Q SPECT/CT). All patients had a history of SARS­CoV­2 infection, diagnosed with a positive real-time polymerase chain reaction (RT-PCR) test. Results Among the 145 patients included in the study, the risk of PE was found to be greater in elderly patients (odds ratio [OR] [95% CI]: 1.05 [1.02­1.07]; p<0.001) and in patients with higher maximum d-dimer levels (OR [95% CI]: 1.14 [1.01­1.3]; p=0.04). We also analyzed the utility of the maximum d-dimer level for predicting acute PE with receiver operating characteristic (ROC) curve analysis. For d­dimer = 0.5 mg/dL, cut-off sensitivity is 91%, specificity is 23%, and for d-dimer = 1 mg/dL, cut-off sensitivity is 79%, specificity is 43% Conclusion D-dimer titers were higher in the PE group in our study. Another significant finding was that, possibly due to thromboinflammation, anticoagulants did not prevent the development of PE in COVID-19 patients.

Lhermitte-Duclos Disease Related With Cowden Syndrome Mimicking Metastatic Lung Cancer on FDG PET/CT.

ABSTRACT: Cowden syndrome is characterized by multiple hamartomatous and neoplastic lesions including Lhermitte-Duclos disease, which is the main criterion for the diagnosis. Herein, we presented a patient with suspected metastatic disease referred to PET/CT, which showed mildly hypermetabolic multinodular thyroid goiter, multiple hamartomatous pulmonary, and breast nodules. Also, intense hypermetabolism was noted on the cerebellar tumor lesion. Lhermitte-Duclos disease was diagnosed based on the characteristic MRI findings, and she was followed up with a diagnosis of Cowden syndrome. Our case indicates that Cowden syndrome should be included as a differential diagnosis of abnormal FDG uptake in the multiple systemic hamartomatous tumors.

Prognostic significance of 18F-FDG PET/CT indices in metastatic renal cell cancer and evaluation of revised IMDC risk model by including 18F-FDG PET-CT parameters.

BACKGROUND: Prognostic markers in metastatic renal cell cancer (mRCC) are still insufficient. Any prognostic model objectively determines disease burden. PURPOSE: To investigate the relationship between 18-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) parameters and outcomes in mRCC, and to define a revised International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model for the intermediate-risk group. MATERIAL AND METHODS: A retrospective study of mRCC was conducted. To investigate the prognostic significance of 18F-FDG PET/CT parameters, maximum standardized uptake value (SUVmax), total lesion glycolysis (TLG), and metabolic tumor volume (MTV) were determined in pre-treatment images. Cutoff values were defined by ROC curve analyses and their association with outcomes was analyzed. Additionally, a TLG-adjusted IMDC model was created by stratifying intermediate-risk group patients according to TLG levels. RESULTS: The study included 52 patients. The disease control rate (DCR) was 61.5% and median overall survival (OS) was 18 months (95% confidence interval=9.2-25.8). In the univariate analyses, IMDC score, MTV, and TLG were prognostic factors for Disease Control Rate (DCR), and Eastern Cooperative Oncology Group (ECOG)-Performance Status (PS), IMDC score, lactate dehydrogenase (LDH), treatment option, MTV, and TLG were prognostic factors for OS (P < 0.05 each). In the multivariate analyses, MTV was an independent prognostic factor for DCR, and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. According to the revised-IMDC model, the intermediate-favorable group showed longer OS than the intermediate-unfavorable group. CONCLUSION: Pretreatment MTV was independent prognostic factor for DCR and ECOG-PS, LDH, IMDC score, and TLG were independent prognostic factors for OS. Revised-IMDC model could identify patients with a worse prognosis among the IMDC intermediate-risk group.

Nasolacrimal Duct Obstruction on 131I SPECT/CT: Atypical False-positive Paranasal Radioiodine Uptake as a Complication of Single-dose RAI Treatment.

Nasolacrimal duct obstruction (NLDO) is a rare complication after radioiodine therapy and may cause false positive 131I uptake at the point of obstruction in 131I whole body scan. Here, we report a 59-year-old female patient with papillary thyroid cancer treated with total thyroidectomy followed by 131I therapy. 131I whole body scan revealed focal uptake in the head. Single photon emission computed tomography/computed tomography (CT) showed focal uptake at the right proximal nasolacrimal duct. The ophthalmologic examination and the diagnostic maxillofacial CT confirmed the diagnosis of NLDO.

Isolated Scapular Lesion of Langerhans Cell Histiocytosis Detected by 18F-FDG PET/CT.

Langerhans cell histiocytosis (LCH) is a rare disease that occurs mainly in pediatric patients and most adult LCH is considered a part of multisystem or multifocal disease. Only 7.3% of cases present as unifocal bone lesion. Herein, we present a case of an isolated scapular lesion of LCH in a 48-year-old man.

Assessment of Takayasu arteritis in routine practice with PETVAS, an 18F-FDG PET quantitative scoring tool.

BACKGROUND: The aim of this study was to evaluate the value of the PET vascular activity score (PETVAS) during the follow-up of patients with Takayasu arteritis. METHODS: Takayasu arteritis patients who underwent 18F-Fluorodeoxyglucose (FDG) PET imaging were evaluated retrospectively. In 8 patients both 1 and 2-h imagings were also performed prospectively. For PETVAS, 9 arterial areas were scored between 0-3 according to the FDG uptake. RESULTS: Forty-six images of 34 patients were evaluated. PETVAS was higher in patients with clinically active disease (p = 0.03) and in the C-reactive protein (CRP) elevated group among clinically inactive patients (p = 0.0015). PETVAS correlated with CRP (p = 0.003, r = 0.53) and erythrocyte sedimentation rate (p = 0.005, r = 0.41), whereas age, disease duration, immunosuppressive, and glucocorticoid (GC) treatments were not associated with PETVAS. First vs. 2nd-h PETVAS was similar in patients who had both 1st and 2nd h PET scans (p = 0.67). DISCUSSION: We observed higher PETVAS in patients with active disease and elevated acute phase reactants. Although scores in our study (performed at one-h) were lower compared to the original PETVAS study performed at two h, PETVAS seems to be a reliable tool to quantify FDG PET scores in routine practice.

18F-FDG PET/CT Metabolic Response With Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Breast Cancer Treated With Cyclin-Dependent 4/6 Kinase Inhibitors.

ABSTRACT: Dysregulation of the cyclin D-CDK4/6-INK4-RB pathway, which leads to uncontrolled cell proliferation, is frequently observed in breast cancer. Recently, 3 CDK4/6 inhibitors have been FDA approved as first-line treatment for patients with hormone receptor-positive, human epidermal growth factor receptor 2-negative advanced breast cancer. Despite promising clinical results, the metabolic response to treatment with these new drugs has not been elaborately demonstrated yet. Herein, we presented a patient with hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer who demonstrated a complete metabolic response on 18F-FDG PET/CT to treatment with a CDK4/6 inhibitor (ribociclib).

Bone Metastasis of Glomus Caroticum Demonstrated on 68 Ga-DOTATATE PET/CT.

ABSTRACT: A 71-year-old man who was diagnosed with carotid body paraganglioma was referred to 68 Ga-DOTATATE PET/CT for primary evaluation, which revealed unknown bony metastasis with intense 68 Ga-DOTATATE uptake. Head and neck paragangliomas are rare neuroendocrine tumors, with a 10% of malignancy rate, and identification of metastatic sites is important in staging and prognosis of the disease. We aimed to highlight the impact of 68 Ga-DOTATATE PET/CT on patient management, especially for equivocal lesions, as in our case.

Azygos Vein Enlargement Secondary to Superior Vena Cava Syndrome on 18 F-FDG PET/CT.

ABSTRACT: Obstruction of the blood flow from the superior vena cava (SVC) to the right atrium causes the SVC syndrome. The azygos system is the most important way to overcome SVC obstruction. Azygos vein enlargement can be seen secondary to the SVC syndrome. Although a few cases showing 18 F-FDG uptake along the SVC in SVC syndrome were reported before, 18 F-FDG PET/CT findings of azygos vein enlargement have not been documented yet. Herein, we presented an intriguing case of azygos vein enlargement secondary to SVC syndrome on 18 F-FDG PET/CT.

Predictive value of 18F-FDG PET/CT indices on extensive residual cancer burden in breast cancer patients treated with neoadjuvant chemotherapy.

AIM: We investigated the correlation between 18F-FDG PET/CT indices and pathological response in breast cancer treated with neoadjuvant chemotherapy (NACT) which was scored with Residual Cancer Burden (RCB) system after surgery. Our aim is to detect extensive residual cancer burden earlier by using PET/CT indices. METHODS: Characteristics of patients were retrieved retrospectively. Baseline maximum Standart Uptake Value (SUVmax), Metabolic Tumor Volume (MTV) and Total Lesion Glycolysis (TLG) indices and reduction rate (RR) between baseline and interim evaluation were calculated with FDG PET/CT scan. All patients were evaluated according to RCB scores after surgery. Pathological responses and PET/CT measurement results were analyzed with demographic and clinical parameters. RESULTS: A total of 95 patients were included in the study. According to pathological responses, the distribution of RCB -0, -1, -2, -3 were 13 (13.7%), 11 (11.6%), 30 (31.6%), 41 (43.2%), respectively. Disease-free survival was significantly lower in the RCB3 group compared to the pathological responder group (p = 0.01). According to multivariate analysis, RR of SUVmax was determined as an independent variable predicting extensive residual cancer burden with an optimal cut-off value of 86% (p < 0.05). CONCLUSIONS: We determined RR of SUVmax as an independent factor for predicting extensive residual tumor burden. We believe that RR of SUVmax is sufficient to predict pathological response in daily practice. In addition, MTV and TLG measurements do not contribute additionally to SUVmax alone and can cause unnecessary labor loss.

Extranodal NK/T-Cell Lymphoma With Widespread Cutaneous and Subcutaneous Involvement on 18 F-FDG PET/CT.

ABSTRACT: Nasal-type extranodal natural killer/T-cell lymphoma is an aggressive rare type of lymphoma that mostly affects the nasal cavity and adjacent areas. However, some patients can present with distant nodal or extranodal involvement including the Waldeyer ring, gastrointestinal tract, genitourinary organs, lung, thyroid, skin, or adrenal glands. Herein, we present a unique case of extranodal natural killer/T-cell lymphoma with widespread cutaneous and subcutaneous involvement on 18 F-FDG PET/CT.

The value of parathyroid scintigraphy on lesion detection in patients with normocalcemic primary hyperparathyroidism.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases. Most of the patients with PHPT are asymptomatic, and only 20% of them become symptomatic with increasing levels of calcium. It has been reported that normocalcemic primary hyperparathyroidism (NPHPT) may be the incipient period of PHPT where calcium (Ca) levels are in normal range, and it may advance to overt PHPT. Early diagnosis of PHPT is important in order to prevent its complications. In this retrospective study, we aimed to evaluate the role of 99mTc-MIBI parathyroid scintigraphy on lesion detection in patients with NPHPT. MATERIAL AND METHODS: The parathyroid scintigraphy database was reviewed retrospectively in patients with PHPT. 117 patients who underwent 99mTc-MIBI scintigraphy were recruited to the study. Serum calcium level above 10.5mg/dl was considered as hypercalcemia. RESULTS: A total of 117 patients (female/male:98/19) mean serum PTH levels (mean±SD) were 149±97pg/ml in normocalcemic group (Ca:9.6±0.6mg/dl, n:38) and 189±135pg/ml in hypercalcemic group (Ca:11.4±0.6mg/dl, n:79) (p:0.072). The sex and ages were not different between the scintigraphy positive and negative groups, but the lesion detection rates with parathyroid scintigraphy were 42% in normocalcemic group and 81% in hypercalcemic group (p<0.0001). CONCLUSIONS: Several factors including serum Ca, the imaging protocol, existence of multiglandular disease, the size and MIBI biokinetics of the adenoma may influence lesion detectability in parathyroid scintigraphy. Although high serum Ca level is an important parameter in predicting its success, parathyroid scintigraphy remains a valuable diagnostic method even in patients with NPHPT.

Hybrid Renal Cortical Imaging with Single Photon Emission Computerized Tomography/Computed Tomography in a Pediatric Patient with Severe Caudal Regression Syndrome.

Caudal regression syndrome (CRS) or sacral agenesis is a rarely seen malformation with a varying degree of structural abnormalities, including multiorgan system dysfunctions, reported with higher incidence among children of mothers with diabetes, as in this case. Spinal anomalies can range from coccyx hemiagenesis to the total absence of lower lumbar vertebrae and sacrum in most severe cases. Herein, we have presented a 9-year-old patient with CRS who had renal failure. Technetium-99m dimercaptosuccinic acid renal scintigraphy revealed bilaterally non-functioning kidneys with no renal cortical uptake. Renal anomalies in CRS with vertebral, anorectal, cardiac, trachea-esophageal, renal, and limb anomalies association include one-sided renal agenesis, multicystic dysplastic kidneys, and ureter duplications.

Detection of Chyle Leakage Site With Lymphoscintigraphy SPECT/CT in a Patient With Chylothorax Secondary to T-Cell Lymphoblastic Leukemia.

ABSTRACT: We present a pediatric case with T-cell lymphoblastic leukemia and persistent chylothorax who was referred to lymphoscintigraphy to identify the site of leakage. Planar lymphoscintigraphy with SPECT/CT revealed hot spots at the left jugulovenous angle and the confluens of the vena brachiocephalica to vena cava, which were compatible with the sites of leakage. Hybrid imaging with SPECT/CT technique have great impact on accurate detection of the defects in the lymphatic system in patients with chylothorax.