Clinical Utility of Positron Emission Tomography/Computed Tomography in Inflammatory Bowel Disease

Purpose  

The clinical utility of positron emission tomography/computed tomography (PET/CT) in comparison to standard workup in patients with known or suspected inflammatory bowel disease (IBD) is unknown.     

Single-photon Emission Tomography/Computed Tomography Delineation of Freiberg Infraction

The role of nuclear medicine diagnostic bone scanning is well established and the influence of coregistration between single-photon emission computed tomography and computed tomography well documented. This case provides an insight into a less frequently encountered pathology in which the combination of single-photon emission computed tomography and computed tomography permitted the differentiation of potential pathology.     

胰高血糖素样肽-1受体PET/CT定位诊断胰岛素瘤的技术规范

胰岛素瘤的诊断和手术治疗依赖于准确的影像学检查定位。以胰腺β细胞为靶点的胰高血糖素样肽-1受体(glucagon-like peptide-1 receptor, GLP-1R)是近年来胰岛素瘤影像研究中的亮点, 推荐临床推广使用⁶⁸Ga-exendin-4进行GLP-1R正电子发射断层显像/计算机体层成像(positron emission tomography/computed tomography, PET/CT)来定位诊断胰岛素瘤。本文介绍GLP-1R显像在胰岛素瘤中的应用概况, 并以⁶⁸Ga-exendin-4 GLP-1R PET/CT显像为例, 介绍该技术的操作规范, 以期为临床提供借鉴。     

Initial Results with 11C-Acetate Positron Emission Tomography/Computed Tomography (PET/CT) in the Staging of Urinary Bladder Cancer

Purpose  

To investigate the utility of ¹¹C-acetate positron emission tomography/computed tomography (PET/CT) for staging of bladder cancer and response assessment after neoadjuvant chemotherapy.     

一例疑似小肠梗阻患者的循证CT诊断

目的针对急诊收治的一例疑似小肠梗阻(SBO)患者,检索当前最佳证据,为临床合理诊断提供依据。方法计算机检索MEDLINE/PubMed (1978～2006．4)、SUMsearch(1978～2006．4)、CNKI(1978～2006．4),查找有关计算机体层摄影术(CT)诊断小肠梗阻的系统评价、横断面研究等,并对所获证据进行评价。结果临床证据表明,与参考标准小肠造影及外科手术诊断相比较,CT诊断小肠梗阻的敏感度和特异度均较高,并能在早期明确梗阻的类型及病因,提高临床医师正确处理小肠梗阻的能力。据此临床证据,结合患者意愿,对患者进行CT检查,CT结果提示绞窄性小肠梗阻,需立即进行手术治疗。结论CT是诊断小肠梗阻敏感性及特异性均较高的影像学检查方法。     

Utility of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in Patients with Fever of Unknown Origin Diagnosed as Lymphoma

Objective

To assess the efficacy of fluorine-18 fluorodeoxyglucose positron emission tomography (¹⁸F-FDG PET)/computed tomography (CT) in the diagnosis of patients with fever of unknown origin (FUO), who were finally diagnosed as lymphoma.

Subjects and Methods

A retrospective study was performed in the First Affiliated Hospital, School of Medicine of Zhejiang University, China, from March 2009 to March 2012. The PET/CT images of consecutive patients with FUO were analyzed. Within 1 week of PET/CT scanning, additional histological tests were also performed if clinically needed.

Results

A total of 73 consecutive patients were included. Of these, 34 (47s%) had a PET/CT finding suggestive of the presence of lymphoma and 29 (85s%) had a diagnosis of confirmed lymphoma; 39 (53s%) had a PET/CT result revealing the absence of lymphoma and 4 (10s%) were diagnosed by biopsy as having lymphoma. The most frequent lymphoma diagnosis was peripheral T cell lymphoma (n = 16; 55s%), followed by diffuse large B cell lymphoma (n = 9; 31s%). The accuracy of PET/CT was 88s%.

Conclusion

In this study, PET/CT had high diagnostic accuracy in patients with FUO resulting from lymphoma, which indicated that PET/CT scanning was a valuable diagnostic tool for these groups of patients with FUO.Key Words: Fever of unknown origin, Positron emission tomography, Computed tomography, Diagnosis, Lymphoma     

Computed Tomography Enterography

Computed tomography enterography (CTE) is an abdominopelvic computed tomography (CT) tailored for evaluation of the small bowel. This multidetector CT examination uses neutral oral contrast to optimally distend small bowel. Patients are scanned after the rapid injection of intravenous contrast during peak bowel wall enhancement. CTE is excellent for the evaluation of many small bowel disorders, particularly Crohn's disease. The purpose of this article is to review CTE indications, contraindications, technique, safety considerations, and imaging findings of common small bowel diseases.     

Role of Low-dose, Noncontrast Computed Tomography from Integrated Positron Emission Tomography/Computed Tomography in Evaluating Incidental 2-Deoxy-2-[F-18]fluoro-d-glucose-avid Colon Lesions

Purpose To assess the contribution of concurrent low-dose, noncontrast CT in the assessment of the malignant potential of incidental focal 2-deoxy-2-[F-18]fluoro-d-glucose (FDG)-avid colonic lesions on positron emission tomography/computed tomography (PET/CT). Procedures Routine FDG-PET/CT scans were reviewed for identification of focal FDG-avid colon lesions, and the CT component was independently reviewed for an anatomical lesion and malignant potential based on CT criteria. Clinical, endoscopic, and histopathology follow-up was obtained. Results A total of 85/2,916 (3%) oncology FDG-PET/CT scans had incidental focal colon lesions. Clinical and/or endoscopic follow-up was available in 83/85 (98%) patients. Focal, corresponding CT lesions were found in 44/83 (53%) patients, but features of malignancy were not assessable. Of the 44 patients with a final diagnosis, 32/44 (73%) were FDG-PET/CT true positives; 5/44 (11%) were false positives; and 7/44 (16%) had inconclusive FDG-PET/CT findings. Conclusions Concurrent low-dose, noncontrast CT improves localization, but does not provide independent information on the malignant potential of incidental focal colonic activity on FDG-PET/CT.     

Multidetector Row Computed Tomography of Small Bowel Obstruction

Small bowel obstruction (SBO) is a common clinical problem, and clinical signs and symptoms often do not provide sufficient information for diagnosis or to guide management. During the past two decades, computed tomography has become a mainstay in the evaluation of patients with known or suspected small bowel obstruction. Computed tomography scans should be performed and interpreted with attention to establishing the diagnosis of small bowel obstruction, locating the transition point indicating the site of obstruction, and determining the cause of the obstruction. Complications that suggest the need for urgent surgical intervention, such as closed loop obstruction with superimposed ischemia and/or volvulus, should be sought in every case. Current generation multidetector row computed tomography scanners, with their isotropic resolution, now permit high-quality reformatted images to be obtained in multiple planes and facilitate identification of the transition point and other findings in SBO. Radiologists should be familiar with the myriad features of uncomplicated and complicated small bowel obstruction, which are reviewed in this article.     

Mixing Matrix-corrected Whole-body Pharmacokinetic Modeling Using Longitudinal Micro-computed Tomography and Fluorescence-mediated Tomography

Molecular Imaging and Biology - Pharmacokinetic modeling can be applied to quantify the kinetics of fluorescently labeled compounds using longitudinal micro-computed tomography and...     

Liver Tuberculosis Presenting as an Uncommon Cause of Pyrexia of Unknown Origin: Positron Emission Tomography/Computed Tomography Identifies the Correct Site for Biopsy

Objective

To identify the correct site to biopsy in a case of pyrexia of unknown origin (PUO) caused by hepatic tuberculosis (TB).

Clinical Presentation and Intervention

A 58-year-old man who developed hepatic TB presented with PUO. Ultrasonography (US) and computed tomography (CT) of the abdomen showed only calcifications in the liver, and positron emission tomography (PET)/CT showed diffuse increased metabolic activity in addition to focal areas of increased activity. A diagnosis of hepatic TB was confirmed by histological examination of liver tissues and interferon-γ release assays (IGRAs of T-SPOT/TB). The patient was treated with 4 anti-tubercular therapies (rifampicin, isoniazid, ethambutol and pyrazinamide). At the 3-month follow-up, the patient was disease free as confirmed by abdominal US.

Conclusion

PET/CT was helpful in identifying a site to biopsy that led to the correct diagnosis.Key Words: Hepatic tuberculosis, Positron emission tomography, Computed tomography, Pyrexia of unknown origin     

In Vivo Quantitation of Intratumoral Radioisotope Uptake Using Micro-Single Photon Emission Computed Tomography/Computed Tomography

Purpose This study was undertaken to determine the ability of micro-single photon emission computed tomography (micro-SPECT)/computed tomography (CT) to accurately quantitate intratumoral radioisotope uptake in vivo and to compare these measurements with planar imaging and micro-SPECT imaging alone.Procedures Human pancreatic cancer xenografts were established in 10 mice. Intratumoral radioisotope uptake was achieved via intratumoral injection of an attenuated measles virus vector expressing the NIS gene (MV-NIS). On various days after MV-NIS injection, ¹²³I planar and micro-SPECT/CT imaging was performed. Tumor activity was determined by dose calibrator measurements and region-of-interest (ROI) image analysis. Agreement and reproducibility of tumor activity measurements were assessed by Bland–Altman plots and Lin’s concordance correlation coefficient (CCC).Results Intratumoral radioisotope uptake was detected in all mice. Scatterplots demonstrate strong agreement (CCC = 0.93) between micro-SPECT/CT ROI image analysis and dose calibrator tumor activity measurements. The differences between dose calibrator activity measurements and those obtained with ROI image analysis of micro-SPECT alone and planar imaging are less accurate and more variable (CCC = 0.84 and 0.78, respectively).Conclusions Micro-SPECT/CT can be used to accurately quantify intratumoral radioisotope uptake in vivo and is more reliable than planar or micro-SPECT imaging alone.     

The Value of Single-photon Emission Computed Tomography/Computed Tomography in the Evaluation of Herniation Pits

The potential role of the nuclear medicine diagnostic bone scan in identifying herniation pits of the femoral neck is yet to be adequately described. The following cases show incidental findings of subcortical cavities of the femoral neck detected on bone scans. These findings highlight the potential role of the bone scan as a useful imaging modality in identifying and stratifying herniation pits based on physiology, particularly with the addition of single-photon emission computed tomography/computed tomography to the armamentarium.     

Imaging of Cardiac Function by Computed Tomography

Cardiac computed tomography has made substantial progress in the past years. While the main application is imaging of the coronary arteries, CT has the potential to provide functional information of the heart. Typically, 10 datasets of the heart are created throughout the cardiac cycle, and can be analyzed manually or with dedicated software algorithms to obtain ventricular volumes, as well as regional and global left and right ventricular function. Numerous comparisons to reference methods such as echocardiography and magnetic resonance imaging have demonstrated high accuracy of computed tomography and very close correlation regarding volumes and ejection fraction. This article outlines image acquisition methods, practical aspects of image acquisition and reconstruction, as well as validation studies of functional cardiac analysis by computed tomography.     

Pediatric Positron Emission Tomography–Computed Tomography Protocol Considerations

Pediatric body oncology positron emission tomography-computed tomography studies require special considerations for optimal diagnostic performance while limiting radiation exposure to young patients. Differences from routine adult procedures include the patient preparation phase, radiopharmaceutical dose, computed tomography acquisition parameters, and approach to computed tomography contrast materials and imaging sequence. Attention to these differences define the best practice for positron emission tomography-computed tomography examinations of children with cancer contributing to optimal care of these patients.     

Combined I-124 Positron Emission Tomography/Computed Tomography Imaging of NIS Gene Expression in Animal Models of Stably Transfected and Intravenously Transfected Tumor

Purpose With the advent of replication competent viruses for cancer gene therapy, it has become imperative to monitor the biodistribution, expression and replication of these vectors in living organisms. We evaluated the potential of I-124 positron emission tomography (PET)/computed tomography (CT) imaging in gene therapy animal models utilizing the sodium iodide symporter (NIS) and compared the findings to I-123 gamma camera imaging. Procedures CB17 SCID mice were implanted with myeloma cell lines expressing NIS or infected by MV-NIS given systemically. Mice were imaged by both gamma camera (I-123) and PET/CT (I-124 ) and image quality assessed. Results NIS expressing tumors concentrated 7.1% of the injected activity while tumors infected with the control virus had only 0.3% of the activity injected. Conclusions I-124 PET/CT in combination with NIS allows the tracking of stably transfected tumors or intravenously transfected tumors. Combined modality imaging using PET/CT allows accurate and non-invasive imaging of the distribution and gene expression of a replicating viral vector in living systems.     

(18)F-fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Findings in Mucosa-associated Lymphoid Tissue Lymphoma of the Larynx: a Case Report and Literature Review

Laryngeal mucosa-associated lymphoid tissue (MALT) lymphoma is rare, with only 25 cases reported in the literature. This report presents a case of laryngeal MALT lymphoma in a 35-year-old female with a 6-year history of progressively worsening hoarseness. MALT lymphoma was diagnosed based on biopsy and immunohistochemical analysis. The patient received two cycles of cyclophosphamide + epirubicin + vincristine + prednisone (CHOP) chemo therapy, which was ineffective. (18)F-fluoro deoxy glucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) showed (18)F-FDG accumulation in the larynx only and identified stage IE lymphoma. CHOP chemotherapy was terminated and the patient was treated with radiotherapy. After 3 months (total radiation dose 27 Gy), (18)F-FDG PET/CT scan showed that the laryngeal lesion was in complete remission. A review of the literature on the MEDLINE(?)/PubMed(?) databases regarding laryngeal MALT lymphoma and the use of PET/CT found that radiotherapy is the firstline treatment for stage I and II MALT lymphoma.     

Technical and Clinical Aspects of Coronary Computed Tomography Angiography

Coronary computed tomography angiography is an emerging imaging technique that has attracted much scientific attention over the past years. Improved scanner technology and dedicated protocols have made noninvasive coronary a reliable diagnostic test in patients with suspected coronary artery disease (CAD). Several technical steps such as the introduction of 64-slice scanners, multisegment reconstruction, and dual-source computed tomography have substantially improved temporal and spatial resolution. With these sophistications, coronary computed tomography angiography enables reliable exclusion of CAD in patients with low to intermediate pretest probability of having CAD or with inconsistent ischemia test results.     

Cardiac Positron Emission Tomography: a Clinical Perspective

Cardiac positron emission tomography is a powerful, quantitative, non-invasive imaging modality, which adds valuable diagnostic and prognostic information to the clinical work-up. Myocardial perfusion and viability imaging are, as a result of continuously growing evidence, established clinical indications that may be cost-effective, due to the high diagnostic accuracy of cardiac positron emission tomography, despite high single-test costs. In the field of inflammation imaging, new indications are entering the clinical arena, which may contribute to a better diagnosis and overall patient care, as for instance in patients with cardiac sarcoidosis, prosthetic valve endocarditis and cardiac device infections. This review will discuss the individual strengths and weaknesses of cardiac positron emission tomography and, hence, the resulting clinical usefulness based on the current evidence for an individualized, patient-centered imaging approach.     

Cardiac Computed Tomography

Computed tomography (CT) has emerged in the past decade as an important tool in the evaluation of cardiac pathology, specifically in the diagnosis of coronary artery disease (CAD). This article will review the technique and role of CT and CT angiography (CTA) in modern cardiovascular care. CT techniques are described, as are the applications of CT in the assessment of CAD including both calcium scoring and CTA. Although CAD is the mainstay of cardiac CT, important noncoronary cardiac applications including the evaluation of cardiac function, masses, valvular disease, and pericardial disease, are reviewed as well. The nursing care of the patient undergoing CTA is reviewed as are future developments within this field.