European Journal of Hybrid Imaging最新文献

Background: Artificial intelligence (AI) technology has been increasingly developed and studied in cardiac imaging. This systematic review summarizes the latest progress of image segmentation, quantification, and the clinical application of AI in evaluating cardiac adipose tissue.

Methods: We exhaustively searched PubMed and the Web of Science for publications prior to 30 April 2021. The search included eligible studies that used AI for image analysis of epicardial adipose tissue (EAT) or pericoronary adipose tissue (PCAT). The risk of bias and concerns regarding applicability were assessed with the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool.

Results: Of the 140 initially identified citation records, 19 high-quality studies were eligible for this systematic review, including 15 (79%) on the image segmentation and quantification of EAT or PCAT and 4 (21%) on the clinical application of EAT or PCAT in cardiovascular diseases. All 19 included studies were rated as low risk of bias in terms of flow and timing, reference standards, and the index test and as having low concern of applicability in terms of reference standards and patient selection, but 16 (84%) studies did not conduct external validation.

Conclusion: AI technology can provide accurate and quicker methods to segment and quantify EAT and PCAT images and shows potential value in the diagnosis and risk prediction of cardiovascular diseases. AI is expected to expand the value of cardiac adipose tissue imaging.

Background: Use of ¹¹C-Choline PET/CT is gaining ground in detecting hyperfunctioning parathyroid glands in primary hyperparathyroidism. The purpose of this study was to evaluate the robustness of ¹¹C-Choline PET/CT by assessing intra- and inter-observer agreement to determine whether the method was reader sensitive and therefore should only be performed at highly specialised sites with a high number of cases. PET/CT images of 40 patients diagnosed with primary hyperparathyroidism were anonymised and evaluated three times by three readers: an expert reader and two non-experts (non-experts were experienced in PET/CT imaging, but not in ¹¹C-Choline PET/CT in the setting of primary hyperparathyroidism). Number of hyperfunctioning parathyroid glands, location relative to the thyroid gland and confidence of each assessment (low, moderate or high) were noted, and intra- and inter-observer agreement calculated using Fleiss' kappa method. Sensitivities and specificities of the non-experts were calculated using the expert reader as gold standard.

Results: Intra-observer agreement was 'good' to 'near perfect' for all readers. Inter-observer agreement was good between non-experts and the expert, with kappa values ≥ 0.74. Sensitivities between non-experts and the expert were high, > 81%, when assessing which side and 75% when assessing thyroid quadrant. All specificities were > 94%. Reader certainties were 'high' in > 80% of cases for the expert and > 70% and > 65%, respectively for the two non-experts.

Conclusion: ¹¹C-Choline PET/CT is not reader sensitive for the localisation of hyperfunctioning parathyroid glands and may therefore be safely implemented at sites that have a moderate number of cases. Access to a cyclotron laboratory is, however, a necessity for the production of ¹¹C-Choline. The study was conducted in accordance with the Helsinki 2 declaration and The International Council for Harmonisation Guideline for Good Clinical Practice (ICH_GCP) clinical trial, approved by the Research Ethics Committee of the Capital Region of Denmark (Journal-nr.:H-18012490, date of approval: 18 June 2018) and the Danish Medicines Agency (EudraCT no. 2018-000726-63, date of approval: 6 June 2018). The GCP unit in Eastern Denmark has carried out regular monitoring of the trial according to GCP (ID: 2018-1050).

Introduction: ⁶⁸Ga-fibroblast activation protein-specific enzyme inhibitor 04 (FAPI-04) is a radiolabelled molecular agent targeting the inhibitor of fibroblast activation protein (FAP), which is often present in tumor stroma and inflammatory tissue with prominent fibroblast proliferation. FAPI-04 is a promising PET tracer for tumor imaging as well as IgG4-related disease (IgG4-RD).

Case description: We herein present a case where ⁶⁸Ga-FAPI PET/MR helped to diagnose IgG4-RD that involved pancreas and bile duct. A 62-year-old patient suffered from diffusive discomfort at middle upper abdomen and presented brown urine. Blood test revealed abnormal liver function and elevated IgG4 (4.830g/L↑). ¹⁸F-FDG PET showed enlarged uncinate process and dilated bile duct tree. Mild increase of FDG uptake in uncinate process and head of pancreas indicated possible pancreatic malignancy, but the clinical evidence was not sufficient and histology examination was negative. ⁶⁸Ga-FAPI PET revealed prominent increased radioactivity distribution in the entire pancreas and bile duct, suggesting IgG4-RD.

Conclusion: FAPI-04 is not only a good PET imaging tracer for tumors, but also for prominent fibroblast-mediated inflammation. FAPI imaging should be considered when the diagnosis using ¹⁸F-FDG imaging is ambiguous. The presented case illustrates that ⁶⁸Ga-FAPI-04 PET is helpful in improving the differential diagnosis of pancreatitis and pancreatic cancer.

Background: Gallium 68-tetraazacyclododecane-tetraacetic acid-octreotate ([68Ga]Ga-DOTA-TATE) is a selective somatostatin analogue ligand, which shows increased affinity for somatostatin receptor subtype (SSTR) 2 and has been used routinely for imaging neuroendocrine tumors with PET/CT. We investigated the utility of [68Ga]Ga-DOTA-TATE positron emission tomography/computed tomography (PET/CT) in patients with suspected pituitary pathology. We reviewed imaging for twenty consecutive patients (8 men, 12 women, mean age of 48.2, range 14-78) with suspected pituitary pathology who were referred for [68Ga]Ga-DOTA-TATE PET/CT.

Results: Nine patients presented with recurrent Cushing's syndrome following surgical resection of pituitary adenomas due to recurrent Cushing's disease (seven patients) and ectopic ACTH secreting tumor (2 patients). All seven patients with recurrent Cushing's disease showed positive pituitary [68Ga]Ga-DOTA-TATE uptake while both cases of ectopic hormonal secretion had absented pituitary uptake. In 1 of these 2 patients, [68Ga]Ga-DOTA-TATE was able to localize the source of ectopic ACTH tumor. Six patients presented de novo with Cushing's due to ectopic ACTH secretion; [68Ga]Ga-DOTA-TATE PET/CT was able to localize ectopic tumors in six of eight patients (3 lungs, 2 pancreases, 1 mid-gut) There was high uptake [68Ga]Ga-DOTA-TATE in 3 cases of recurrent central hyperthyroidism (SUVmax 6.6-14.3) and 2 cases of prolactinoma (SUVmax 5.5 and 11.3).

Conclusion: Absent [68Ga]Ga-DOTA-TATE activity in the pituitary fossa is useful in excluding pituitary disease in recurrent Cushing's. Recurrent pituitary thyrotropinomas and prolactinomas showed moderate to high pituitary activity. In addition, in Cushing's syndrome, [68Ga]Ga-DOTA-TATE is useful for detection of ectopic sources of ACTH production, especially where anatomic imaging is negative.

Background: Pancreatic neuroendocrine tumor (PNET) is a subgroup of neuroendocrine tumor (NET) that has unique biology and natural history. The histological classification has a major role in the management of this pathology, but in recent years Gallium 68 dotatate (68Ga-DOTA) scanning is at the center of a discussion about how these imaging technologies can modify clinical management of neuroendocrine tumors and how their results are correlated to Ki67 index.

Method: We hereby describe a case of a patient that investigated an unspecific stable pancreatic nodule suspected of high-grade NET after evaluation with 68Ga-DOTATOC positron emission tomography-computed tomography (PETCT) and ¹⁸F-Fluorodeoxyglucose (¹⁸F-FDG) PETCT.

Results: The images corroborate the hypothesis of high-grade NET based on the standard uptake value (SUV) described in both image exams (16.4 in ¹⁸FDG PETCT and 9.2 in 68Ga-DOTATOC PETCT). After surgery, the histopathological analyses revealed a localized grade 2 well-differentiated NET, Ki-67 of 4.7, glucose transport proteins 1 (GLUT1) negative by immunohistochemistry, evidencing a rare case of mismatch between the functional image and the in vivo characterization of the neoplasm.

Conclusion: Functional imaging of neuroendocrine tumors with different modalities of PETCT is a well-described strategy for evaluating PNET and can dictate conducts in some cases. However, histopathological analysis is crucial to confirm the grade and prognosis related to this disease.

Background: SMARCA4-deficient thoracic tumor (SMARCA4-DTT) is a distinct entity of undifferentiated thoracic malignancies newly introduced in 2015. Due to its unique clinical characteristic with aggressive thoracic tumor mostly observed in heavy smoker man with emphysema, with poor prognosis, many physicians are becoming increasingly aware of the disease; however, reports on 2-deoxy-2-[¹⁸F] fluoroglucose positron emission tomography/computed tomography ([¹⁸F]FDG PET/CT) have been limited; thus, this disease is not yet widely known to nuclear medicine clinicians. As a first step in discussing the usefulness of [¹⁸F]FDG PET/CT for this disease, we present a case in which [¹⁸F]FDG PET/CT played a clinically important role.

Case: A 74-year-old heavy smoker man with an anamnesis of severe emphysema characterized by pleural thickening and abnormal enhancement in CT underwent 18F-FDG PET/CT for further examination. [¹⁸F]FDG-avid pleural nodules infiltrating into the chest wall were detected and pathologically diagnosed as SMARCA4-DTT with biopsy.

Conclusion: SMARCA4-deficient thoracic tumor should be considered in a [¹⁸F]FDG-avid aggressive thoracic tumor in heavy smoker men with emphysema.

Background: Patients with metastatic cancer to the brain have a poor prognosis. In clinical practice, MRI is used to delineate, diagnose and plan treatment of brain metastases. However, MRI alone is limited in detecting micro-metastases, delineating lesions and discriminating progression from pseudo-progression. Combined PET/MRI utilises superior soft tissue images from MRI and metabolic data from PET to evaluate tumour structure and function. The amino acid PET tracer ¹⁸F-FACBC has shown promising results in discriminating high- and low-grade gliomas, but there are currently no reports on its use on brain metastases. This is the first study to evaluate the use of ¹⁸F-FACBC on brain metastases.

Case presentation: A middle-aged female patient with brain metastases was evaluated using hybrid PET/MRI with ¹⁸F-FACBC before and after stereotactic radiotherapy, and at suspicion of recurrence. Static/dynamic PET and contrast-enhanced T1 MRI data were acquired and analysed. This case report includes the analysis of four ¹⁸F-FACBC PET/MRI examinations, investigating their utility in evaluating functional and structural metastasis properties.

Conclusion: Analysis showed high tumour-to-background ratios in brain metastases compared to other amino acid PET tracers, including high uptake in a very small cerebellar metastasis, suggesting that ¹⁸F-FACBC PET can provide early detection of otherwise overlooked metastases. Further studies to determine a threshold for ¹⁸F-FACBC brain tumour boundaries and explore its utility in clinical practice should be performed.

Multiple myeloma is characterized by malignant proliferation of clonal plasma cells. Usually, appears as a generalized disease but it can present as solitary bone plasmacytoma or a solitary soft tissue mass or extramedullary plasmacytoma. In the case of extramedullary involvement, it could present as soft tissue plasmacytomas and the prognosis is poor. The 18F-FDG PET/CT could be a valuable tool for characterization of the medullary and extramedullary involvement. We present a case of F18-FDG PET/CT with extramedullary involvement with soft tissue plasmacytomas in the setting of MM.

Background: Respiratory motion during PET imaging reduces image quality. Data-driven gating (DDG) based on principal component analysis (PCA) can be used to identify respiratory signals. The use of DDG, without need for external devices, would greatly increase the feasibility of using respiratory gating in a routine clinical setting. The objective of this study was to evaluate data-driven gating in relation to external hardware gating and regular static image acquisition on PET-MRI data with respect to SUV_max and lesion volumes.

Methods: Sixteen patients with esophageal or gastroesophageal cancer (Siewert I and II) underwent a 6-min PET scan on a Signa PET-MRI system (GE Healthcare) 1.5-2 h after injection of 4 MBq/kg ¹⁸F-FDG. External hardware gating was done using a respiratory bellow device, and DDG was performed using MotionFree (GE Healthcare). The DDG raw data files and the external hardware-gating raw files were created on a Matlab-based toolbox from the whole 6-min scan LIST-file. For comparison, two 3-min static raw files were created for each patient. Images were reconstructed using TF-OSEM with resolution recovery with 2 iterations, 28 subsets, and 3-mm post filter. SUV_max and lesion volume were measured in all visible lesions, and noise level was measured in the liver. Paired t-test, linear regression, Pearson correlation, and Bland-Altman analysis were used to investigate difference, correlation, and agreement between the methods.

Results: A total number of 30 lesions were included in the study. No significant differences between DDG and external hardware-gating SUV_max or lesion volumes were found, but the noise level was significantly reduced in the DDG images. Both DDG and external hardware gating demonstrated significantly higher SUV_max (9.4% for DDG, 10.3% for external hardware gating) and smaller lesion volume (- 5.4% for DDG, - 6.6% for external gating) in comparison with non-gated static images.

Conclusions: Data-driven gating with MotionFree for PET-MRI performed similar to external device gating for esophageal lesions with respect to SUV_max and lesion volume. Both gating methods significantly increased the SUV_max and reduced the lesion volume in comparison with non-gated static acquisition. DDG resulted in reduced image noise compared to external device gating and static images.

Purpose: To evaluate the diagnostic accuracy of SPECT/CT arthrography in patients with suspected aseptic prosthesis loosening following hip and knee arthroplasty.

Methods: A retrospective review of 63 SPECT/CT arthrogram studies (36 knees and 27 hips) between February 1, 2013, and July 1, 2018, was conducted. All patients underwent clinical and radiologic evaluation as part of their assessment for persistent pain following hip and knee arthroplasty. The detection of tracer activity along the bone-prosthetic interface on SPECT/CT suggests aseptic loosening. Operative assessment as well as clinical/radiologic follow-up at a minimum of 1 year was used as the reference standard.

Results: The sensitivity and specificity of SPECT/CT for detection of aseptic loosening was 6/7 (86%) and 55/56 (98%), respectively. This gives a positive predictive value (PPV) of 6/7 (86%), a negative predictive value (NPV) of 55/56 (98%), and a diagnostic accuracy of 61/63 (97%).

Conclusion: SPECT/CT arthrography has a high diagnostic accuracy (97%) in the evaluation of loosening of both hip and knee arthroplasties in patients with persistent post-procedural pain.