Utility Of Positron Emission Tomography-computed Tomography Research Articles

Utility of PET-CT in Newly Diagnosed HPV-Associated Oropharyngeal Squamous Cell Carcinoma.

To compare the utility of positron emission tomography-computed tomography (PET-CT) versus contrasted CT neck combined with routine chest imaging for disease staging and treatment planning in human papillomavirus (HPV) associated oropharyngeal squamous cell carcinoma (OPSCC) with clinically evident sites of primary disease. All adult patients with primary HPV-associated OPSCC at a single quaternary care cancer center from 2018 to 2019 were reviewed, and those with images available for re-review were included. Primary outcomes included concordance in clinical staging between the 2 imaging modalities of interest (PET-CT vs CT), as well as independent agreement of each with pathologic staging. Analysis was performed via ordinal logistic regression. A secondary outcome was treatment selection after diagnostic imaging, analyzed via chi-squared testing. In total, 100 patients were included for evaluation, of which 89% were male, 91% Caucasian, and mean age was 61.2 years (SD 9.6). Clinical disease staging agreed between imaging modalities in 95% of cases (54 of 57 patients). Pathologic staging agreed with clinical staging from CT neck in 93% of cases (25 of 27 patients; P = .004), and with PET-CT in 82% (14 of 17 patients; P =.003). No differences were observed between the 2 imaging modalities for subsequent treatment selection (P = .39). In uncomplicated HPV-associated OPSCC, CT offers equivalent diagnostic accuracy to that of combined whole-body PET-CT for clinical staging, and has no appreciable impact on treatment selection. A reduced reliance on routine PET-CT during initial workup of HPV-associated OPSCC may be favorable for otherwise healthy patients with clinically evident sites of primary disease.

PET-CT scan in the preoperative workup of early stage intermediate- and high-risk endometrial cancer

Objectives: To evaluate positron emission tomography-computed tomography (PET-CT) for the preoperative management of early-stage intermediate- and high-risk endometrial cancer (EC).Study design: Data of patients with intermediate- and high-risk early-stage EC were retrieved from a prospectively collected database. Patients with preoperative PET-CT followed by surgical staging including pelvic lymphadenectomy were analyzed. Diagnostic performance for lymph node (LN) metastasis was evaluated.Results: Overall, 45 patients were included: 27 (60%) and 18 (40%) with intermediate- and high-risk EC, respectively. Four patients (8.8%) had LN metastasis, three correctly identified at PET-CT, yielding a sensitivity of 75% (95% CI 21.9–98.7). Among 41 patients (91.2%) without LN metastasis, 38 had negative PET-CT with specificity of 92.7% (95% CI 78.9–98.1). The negative predictive value (NPV) was 97.4% (95% CI 84.9–99.9) and the positive predictive value was 50% (95% CI 13.9–86.1).Conclusions: The utility of PET-CT is limited by the low sensitivity for LN metastasis in intermediate- and high-risk early-stage EC, that may impede to consider PET-CT alone an adequate alternative to surgical retroperitoneal staging by lymphadenectomy or sentinel LN biopsy. However, the high diagnostic accuracy, specificity and NPV might support its adoption to improve the diagnostic accuracy of the sentinel LN algorithm.

Non traumatic vertebral lesions: incremental utility of PET-CT over MRI and FNAC in a suggested diagnostic algorithm

Objective: To prospectively compare positron emission tomography-computed tomography (PET-CT) with conventional magnetic resonance imaging (MRI) and FNAC for diagnosis of non- traumatic vertebral lesions fracture in countries like India where tuberculosis is endemic.Methods: Fifty four patients with non-traumatic spontaneous vertebral lesions were prospectively studied. All patients underwent CEMRI focusing on the spinal lesions, whole-body PET-CT and FNAC.Results were then analysed and compared with final diagnosis obtained either by FNAC or clinical follow up.Results: Out of total 54 patients, FNAC from the spinal lesion could establish diagnosis in 36 patients (26 TB, 1 Fungal and 9 tumors). Of the remaining 18 patients, diagnosis could be established in 7 utilizing FNAC from other sites as dictated by PET-CT. In the remanining11 patients, the diagnosis and management was decided on the concordance of MRI and PET-CT.Conclusion: All three investigations have their own advantages and pitfalls and they complement each other in reaching the final diagnosis. MRI has a better pick up rate (than PET-CT) for inflammatory lesions. PET-CT on the other hand has better sensitivity for malignant vertebral disease. Diagnosis was established if FNAC was conclusive. In cases where FNAC was inconclusive, an additional 38.9% patients’ diagnosis could be established by FNAC from other sites of involvement as dictated by PET-CT. This was an incremental utility of PET–CT. When even this fails, there were two possible scenarios—MRI and PET-CT in concordance with each other. In such a scenario, the combined report of MRI and PET-CT was relied upon. The last sub group (where MRI and PET-CT were discordant and FNAC was inconclusive) still remains achilles’ heel. Wide bore biopsy may help in establishing diagnosis in such group.

Imaging Copper Metabolism Imbalance in Atp7b −/− Knockout Mouse Model of Wilson’s Disease with PET-CT and Orally Administered 64CuCl2

This study aims to determine the feasibility and utility of functional imaging of copper metabolism imbalance in Atp7b (-/-) knockout mouse model of Wilson's disease (WD) with positron emission tomography-computed tomography (PET-CT) using orally administered copper-64 chloride ((64)CuCl(2)) as a tracer. Atp7b (-/-) KO mice (N = 5) were subjected to PET scanning using a hybrid PET-CT scanner, after oral administration of (64)CuCl(2) as a tracer. Time-dependent PET quantitative analysis was performed to assess gastrointestinal absorption and biodistribution of (64)Cu radioactivity in the Atp7b (-/-) KO mice, using C57BL wild-type (WT) mice (N = 5) as a normal control. Estimates of human radiation dosimetry were calculated based on biodistribution of (64)Cu radioactivity in live animals. PET-CT analysis demonstrated higher (64)Cu radioactivity in the liver of Atp7b (-/-) knockout mice compared with that in the control C57BL WT mice (p < 0.001), following oral administration of (64)CuCl(2) as a tracer. In addition, (64)Cu radioactivity in the lungs of the Atp7b (-/-) knockout mice was slightly higher than those in the control C57BL WT mice (p = 0.01). Despite initially higher renal clearance of (64)Cu, there was no significant difference of (64)Cu radioactivity in the kidneys of the Atp7b (-/-) KO mice and the control C57BL WT mice at 24h post-oral administration of (64)CuCl(2) (p = 0.16). There was no significant difference in low (64)Cu radioactivity in the blood, brain, heart, and muscles between the Atp7b (-/-) knockout mice and control C57BL WT mice (p > 0.05). Based on the biodistribution of (64)Cu radioactivity in C57BL WT mice, radiation dosimetry estimates of (64)Cu in normal human subjects were obtained. An effective dose (ED) of 42.4μSv/MBq (weighted dose over 22 organs) was calculated and the lower large intestines were identified as the critical organ for radiation exposure (120μGy/MBq for males and 135μGy/MBq for females). Radiation dosimetry estimates for patients with WD, derived from the biodistribution of (64)Cu in Atp7b (-/-) KO mice, showed a slightly lower ED of 37.5μSv/MBq, with the lower large intestines as the critical organ for radiation exposure (83μSv/MBq for male and 95μSv/MBq for female). PET-CT quantitative analysis demonstrated an increased level of (64)Cu radioactivity in the liver of Atp7b (-/-) KO mice compared with that in the control C57BL WT mice, following oral administration of (64)CuCl(2) as a tracer. The results of this study suggest the feasibility and utility of PET-CT using orally administered (64)CuCl(2) as a tracer ((64)CuCl(2)-PET/CT) for functional imaging of copper metabolism imbalance in WD.

Identification of Distant Metastases With Positron–Emission Tomography‐Computed Tomography in Patients With Previously Untreated Head and Neck Cancer

To investigate the utility of positron-emission tomography-computed tomography (PET-CT) in identifying distant metastatic disease in patients with previously untreated head and neck squamous cell cancer (HNSCC) prior to definitive treatment. Retrospective analysis of 27 consecutive patients with previously untreated HNSCC who underwent PET-CT imaging in addition to chest radiography (CXR) as part of their metastatic workup. The majority of patients (89%) had TNM stage III or IV disease. PET-CT was suspicious for pulmonary malignancy in four (15%) patients and indeterminate in one (4%) patient. CXR was suspicious for pulmonary malignancy in two (7%) patients. Pulmonary metastases or a new lung primary was present in 3 (11%) patients: 3 of 4 (75%) patients with positive PET-CT scans and 0 of 23 (0%) patients with negative or indeterminate PET-CT scans compared with 2 of 2 (100%) patients with positive CXR and 1 of 25 (4%) patients with negative CXR. The sensitivity and specificity of PET-CT in predicting pulmonary malignancy was 100% and 96%, respectively, with a positive predictive value of 75% and a negative predictive value of 100%. The sensitivity and specificity of CXR in predicting pulmonary malignancy was 67% and 100%, respectively, with a positive predictive value of 100% and a negative predictive value of 96%. Including nonpulmonary sites, the overall incidence of distant metastatic disease was 19% (5/27) with 11% (3/27) unsuspected prior to PET-CT. PET-CT improves detection of metastatic disease in the high-risk patient and should be performed as part of the routine pretreatment evaluation of patients with advanced stage HNSCC.