SPECT/CT in infection and inflammation

Short-Term Outcomes of Intraarticular Corticosteroid Injection into the Lumbar Facet Joint According to the Findings of Single-Photon Emission Computed Tomography Imaging

Objective

Bone single-photon emission computed tomography (SPECT) preferentially localizes areas exhibiting greater bone remodeling and enhanced perfusion, which helps identify areas of pain and inflammation in the lumbar facet joints (LFJs). Herein, we investigated the treatment outcome of intraarticular (IA) corticosteroid injection in patients with LFJ-origin lower back pain (LBP) depending on the presence of increased LFJ uptake on bone SPECT.

Methods

We retrospectively recruited 38 patients with LFJ-origin LBP. Of the 38 patients, 22 patients showed increased uptake on bone SPECT (SPECT+ group), and 16 patients did not show increased uptake on bone SPECT (SPECT- group). A numeric rating scale (NRS) was used to assess pain reduction 1 month after treatment with a corticosteroid injection. Treatment was considered successful when the posttreatment NRS score was ≥50% lower than the pretreatment NRS score.

Results

The NRS scores of the SPECT+ group at the 1-month follow-up were significantly lower than those of the SPECT- group. Additionally, the degree of change in the NRS scores was larger in the SPECT+ group than that in the SPECT- group. In addition, 18 of the 22 patients (81.8%) in the SPECT+ group underwent successful treatment. Eight of the 16 patients (50%) in the SPECT- group underwent successful treatment. The ratio of successful treatment was significantly higher in the SPECT+ group than in the SPECT- group.

Discussion

Bone SPECT could help predict the therapeutic outcome after IA LFJ corticosteroid injection and determine the treatment plan for patients with LFJ-origin LBP.

18F-FDG PET/CT and Radiolabeled Leukocyte SPECT/CT Imaging for the Evaluation of Cardiovascular Infection in the Multimodality Context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations From ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multisocietal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multifocal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

18F-FDG PET/CT and radiolabeled leukocyte SPECT/CT imaging for the evaluation of cardiovascular infection in the multimodality context: ASNC Imaging Indications (ASNC I2) Series Expert Consensus Recommendations from ASNC, AATS, ACC, AHA, ASE, EANM, HRS, IDSA, SCCT, SNMMI, and STS

This document on cardiovascular infection, including infective endocarditis, is the first in the American Society of Nuclear Cardiology Imaging Indications (ASNC I2) series to assess the role of radionuclide imaging in the multimodality context for the evaluation of complex systemic diseases with multi-societal involvement including pertinent disciplines. A rigorous modified Delphi approach was used to determine consensus clinical indications, diagnostic criteria, and an algorithmic approach to diagnosis of cardiovascular infection including infective endocarditis. Cardiovascular infection incidence is increasing and is associated with high morbidity and mortality. Current strategies based on clinical criteria and an initial echocardiographic imaging approach are effective but often insufficient in complicated cardiovascular infection. Radionuclide imaging with 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and single photon emission computed tomography/CT leukocyte scintigraphy can enhance the evaluation of suspected cardiovascular infection by increasing diagnostic accuracy, identifying extracardiac involvement, and assessing cardiac implanted device pockets, leads, and all portions of ventricular assist devices. This advanced imaging can aid in key medical and surgical considerations. Consensus diagnostic features include focal/multi-focal or diffuse heterogenous intense 18F-FDG uptake on valvular and prosthetic material, perivalvular areas, device pockets and leads, and ventricular assist device hardware persisting on non-attenuation corrected images. There are numerous clinical indications with a larger role in prosthetic valves, and cardiac devices particularly with possible infective endocarditis or in the setting of prior equivocal or non-diagnostic imaging. Illustrative cases incorporating these consensus recommendations provide additional clarification. Future research is necessary to refine application of these advanced imaging tools for surgical planning, to identify treatment response, and more.

Imaging in osteoarticular infection in adults

BACKGROUND

Osteoarticular infections are uncommon and required a multimodal approach for diagnosis. Imaging forms an important component of this multimodal approach.

OBJECTIVES

In this narrative review, we describe the different imaging modalities, features of osteoarticular infections present on these imaging approaches and recommendations for which imaging modality should be considered in different types of osteoarticular infections.

SOURCES

This narrative review was based on literature review from PubMed and was limited to bacterial infections in adult patients.

CONTENT

Imaging modalities include modalities that provide information on the anatomy or radionuclide imaging that provides information about the metabolic activity of the area of interest. Anatomical imaging includes plain radiographs (X-ray), computed tomography, and magnetic resonance imaging. Radionuclide approaches include three-phase bone scintigraphy, gallium scans, white blood cell scintigraphy, and 18F-fluorodeoxy-glucose positron emission tomography. The optimal radiological modality for diagnosis is influenced by multiple factors, including infection location, presence of metalware, timing of infection from any preceding surgery or fracture, antibiotic use, and patient comorbidities. Local availability of scanning modality, tracer supply, technical expertise, and patient access also influences choice.

IMPLICATIONS

A collaborative approach with imaging, pathology and clinical input in a multidisciplinary setting is paramount for the diagnosis of osteoarticular infections. Increasing research and improvements in technology will further improve the utility and accuracy of imaging approaches for imaging in osteoarticular infections.

Technical concepts on blood pool phase SPECT (acquisition, reconstruction)

Guidelines for bone scintigraphy are well established and recommend the use of planar early phase images to investigate a number of clinical indications. With recent advances in gamma camera technology the use of SPECT/CT imaging in the early phases is now possible, offering the potential of improved diagnostic confidence and prognostic value. To date little work has been carried out to optimize the acquisition of early phase bone images using SPECT/CT with most of the available studies acquiring SPECT images after the traditional planar images to allow comparison of the two techniques. Imaging durations of 7 to 10 minutes have been commonly used. However, the use of iterative reconstruction algorithms has been investigated with rapid SPECT imaging to allow imaging durations as low as 4 minutes. The use of CZT based systems with increased sensitivity and improved energy and spatial resolution also offers the potential to reduce imaging times. The optimization of projection measurement order has been investigated as a method of reducing image artefacts as a result of changing tracer distribution during the SPECT acquisition. In this article we consider the current state of early phase SPECT imaging and possible areas for future investigation as well as recommendations for departments looking to adopt blood pool SPECT imaging as part of their routine clinical practice.

Terminal ileal micro-perforation from an ingested fish bone incidentally diagnosed with 111In-leukocyte scintigraphy in an asymptomatic patient

¹¹¹In-leukocyte scintigraphy has generally been considered a sensitive diagnostic test for the evaluation of infectious or inflammatory processes in the abdomen due to a lack of normal physiologic bowel activity. Herein we present a case of a patient status post endovascular repair of an abdominal aortic aneurysm for which an ¹¹¹In-leukocyte scan was ordered to assess for graft infection. Planar imaging revealed an abnormal focus of radiotracer activity in the right lower quadrant of the abdomen. A SPECT-CT obtained to further delineate the anatomic location of abnormal activity showed abnormal leukocyte activity localizing to the terminal ileum secondary to a micro-perforation from an ingested fishbone. This case underscores the principle that in the absence of known intra-abdominal pathology, ¹¹¹In-leukocyte activity in the abdomen should always be considered abnormal, and that further evaluation with dedicated cross-sectional imaging should be performed to assist with the localization of abnormal activity.

Radionuclide Imaging of Fungal Infections and Correlation with the Host Defense Response

The human response to invading fungi includes a series of events that detect, kill, or clear the fungi. If the metabolic host response is unable to eliminate the fungi, an infection ensues. Some of the host response’s metabolic events to fungi can be imaged with molecules labelled with radionuclides. Several important clinical applications have been found with radiolabelled biomolecules of inflammation. ¹⁸F-fluorodeoxyglucose is the tracer that has been most widely investigated in the host defence of fungi. This tracer has added value in the early detection of infection, in staging and visualising dissemination of infection, and in monitoring antifungal treatment. Radiolabelled antimicrobial peptides showed promising results, but large prospective studies in fungal infection are lacking. Other tracers have also been used in imaging events of the host response, such as the migration of white blood cells at sites of infection, nutritional immunity in iron metabolism, and radiolabelled monoclonal antibodies. Many tracers are still at the preclinical stage. Some tracers require further studies before translation into clinical use. The application of therapeutic radionuclides offers a very promising clinical application of these tracers in managing drug-resistant fungi.

Imaging Inflammation - From Whole Body Imaging to Cellular Resolution

Imaging techniques have evolved impressively lately, allowing whole new concepts like multimodal imaging, personal medicine, theranostic therapies, and molecular imaging to increase general awareness of possiblities of imaging to medicine field. Here, we have collected the selected (3D) imaging modalities and evaluated the recent findings on preclinical and clinical inflammation imaging. The focus has been on the feasibility of imaging to aid in inflammation precision medicine, and the key challenges and opportunities of the imaging modalities are presented. Some examples of the current usage in clinics/close to clinics have been brought out as an example. This review evaluates the future prospects of the imaging technologies for clinical applications in precision medicine from the pre-clinical development point of view.

Radiochemistry: A Useful Tool in the Ophthalmic Drug Discovery

Positron Emission Tomography (PET) and Single Photon Emission Computerized Tomography (SPECT) are ultra-sensitive, fully translational and minimally invasive nuclear imaging techniques capable of tracing the spatiotemporal distribution of positron (PET) or gamma (SPECT) emitter-labeled molecules after administration into a living organism. Besides their impact in the clinical diagnostic, PET and SPECT are playing an increasing role in the process of drug development, both during the evaluation of the pharmacokinetic properties of new chemical entities as well as in the proof of concept, proof of mechanism and proof of efficacy studies. However, they have been scarcely applied in the context of ophthalmic drugs. In this paper, the basics of nuclear imaging and radiochemistry are briefly discussed, and the few examples of the use of these imaging modalities in ophthalmic drug development reported in the literature are presented and discussed. Finally, in a purely theoretical exercise, some labeling strategies that could be applied to the preparation of selected ophthalmic drugs are proposed and potential applications of nuclear imaging in ophthalmology are projected.

Two decades of SPECT/CT - the coming of age of a technology: An updated review of literature evidence

PURPOSE

Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) was introduced as a hybrid SPECT/CT imaging modality two decades ago. The main advantage of SPECT/CT is the increased specificity achieved through a more precise localization and characterization of functional findings. The improved diagnostic accuracy is also associated with greater diagnostic confidence and better inter-specialty communication.

METHODS

This review presents a critical assessment of the relevant literature published so far on the role of SPECT/CT in a variety of clinical conditions. It also includes an update on the established evidence demonstrating both the advantages and limitations of this modality.

CONCLUSIONS

For the majority of applications, SPECT/CT should be a routine imaging technique, fully integrated into the clinical decision-making process, including oncology, endocrinology, orthopaedics, paediatrics, and cardiology. Large-scale prospective studies are lacking, however, on the use of SPECT/CT in certain clinical domains such as neurology and lung disorders. The review also presents data on the complementary role of SPECT/CT with other imaging modalities and a comparative analysis, where available.

67Ga Scintigraphy for Assessment of Disease Severity and Treatment Response in Patients With Paracoccidioidomycosis

OBJECTIVE

The evaluation of therapy response of patients with deep mycosis is a major challenge. The aim of this study was to assess the severity of disease at admission and evaluate treatment response of patients with paracoccidioidomycosis using Ga scintigraphy.

SUBJECTS AND METHODS

Seventy-three patients with fully active disease were enrolled. A scoring system based on clinicoradiological and serological evaluation and Ga scan was devised. Pretherapy Ga score of 73 patients was compared with clinicoradiological and serological scores. A subgroup of 23 patients was followed up during treatment, and the rates of improvement of their clinicoradiological, serological, and Ga scores during treatment were compared at 3 time points (fully active phase, after clinical improvement, and clinically inactive disease).

RESULTS

The correlations between scores before therapy were statistically significant. Ga score correlated with clinical score (r = 0.47, P < 0.001). Serological score correlated with both Ga and clinical scores (r = 0.32, P = 0.006, and r = 0.25, P = 0.034, respectively). Concerning evaluation of therapy response, clinicoradiological, serological, and Ga scores decreased significantly after therapy (P < 0.001). Notably, Ga score was the single one to become negative in most patients at the end of treatment (20 of 23 patients compared with 7 on clinicoradiological evaluation and 10 on serology, P = 0.003).

CONCLUSIONS

In patients with paracoccidioidomycosis, pretherapy Ga scintigraphy correlates with disease severity. Serial Ga scans seem to be helpful in evaluating the response to therapy.

The Clinical Dilemma of Incidental Findings on the Low-Resolution CT Images from SPECT/CT MPI Studies

Incidental findings are common in medical imaging. There is a particularly high prevalence of incidental findings within the thorax, the most frequent being pulmonary nodules. Although pulmonary nodules have the potential to be malignant, most are benign, resulting in a high number of false-positive findings. Low-resolution CT images produced for attenuation correction of SPECT images are essentially a by-product of the imaging process. The high number of false-positive incidental findings detected on these attenuation-correction images causes a reporting dilemma. Early detection of cancer can be beneficial, but false-positive findings and overdiagnosis can be detrimental to the patient. Attenuation-correction CT images are not of diagnostic quality, and further diagnostic tests are usually necessary for a definitive diagnosis to be reached. Given the high number of false-positive findings, the psychologic effect on the patient should be considered. This review recommends caution when the findings on attenuation-correction CT images are routinely reported.