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- Loizou, L., et al.
(författare)
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Multidetector CT of pancreatic ductal adenocarcinoma : Effect of tube voltage and iodine load on tumour conspicuity and image quality
- 2016
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Ingår i: European Radiology. - : Springer Science and Business Media LLC. - 0938-7994 .- 1432-1084. ; 26:11, s. 4021-4029
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To compare a low-tube-voltage with or without high-iodine-load multidetector CT (MDCT) protocol with a normal-tube-voltage, normal-iodine-load (standard) protocol in patients with pancreatic ductal adenocarcinoma (PDAC) with respect to tumour conspicuity and image quality.METHODS: Thirty consecutive patients (mean age: 66 years, men/women: 14/16) preoperatively underwent triple-phase 64-channel MDCT examinations twice according to: (i) 120-kV standard protocol (PS; 0.75 g iodine (I)/kg body weight, n = 30) and (ii) 80-kV protocol A (PA; 0.75 g I/kg, n = 14) or protocol B (PB; 1 g I/kg, n = 16). Two independent readers evaluated tumour delineation and image quality blindly for all protocols. A third reader estimated the pancreas-to-tumour contrast-to-noise ratio (CNR). Statistical analysis was performed with the Chi-square test.RESULTS: Tumour delineation was significantly better in PB and PA compared with PS (P = 0.02). The evaluation of image quality was similar for the three protocols (all, P > 0.05). The highest CNR was observed with PB and was significantly better compared to PA (P = 0.02) and PS (P = 0.0002).CONCLUSION: In patients with PDAC, a low-tube-voltage, high-iodine-load protocol improves tumour delineation and CNR leading to higher tumour conspicuity compared to standard protocol MDCT.KEY POINTS: • Low-tube-voltage high-iodine-load MDCT improves pancreatic cancer conspicuity compared to a standard protocol. • The pancreas-to-tumour attenuation difference increases significantly by reducing the tube voltage. • The radiation exposure dose decreases by reducing the tube voltage.
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- Pálsdóttir, K, et al.
(författare)
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Inter-observer agreement of transvaginal ultrasound and magnetic resonance imaging in local staging of cervical cancer.
- 2021
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Ingår i: Ultrasound in Obstetrics and Gynecology. - : Wiley. - 0960-7692 .- 1469-0705. ; 58:5, s. 773-779
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To evaluate the inter-observer agreement in relation to observer experience for the assessment of local tumor extension in women with cervical cancer, using transvaginal ultrasound (US) and magnetic resonance imaging (MRI).METHODS: The observers comprised six US specialists with, and seven without previous experience of cervical cancer assessment, five experienced radiologists in pelvic MRI, and four less experienced radiology residents without previous MRI experience. The less experienced US observers, and all MRI observers underwent comprehensive training on assessment of cervical tumor extension while experienced US observers received written directives. All observers were assigned the same images from cervical cancer patients of all stages (n=60) for off-line evaluation on tumor detection, cervical stromal- (>1/3), and parametrial invasion. Inter-observer agreement was measured using Fleiss kappa, with 95% CI.RESULTS: Experienced and less experienced US observers had moderate agreement regarding tumor detection Fleiss κ [95% CI] (0.46 [0.40-0.53], and 0.46 [0.41-0.52]), stromal invasion (0.45 [0.38-0.51] and 0.53 [0.40-0.58]) and parametrial invasion (0.57 [0.51-0.64], and 0.44 [0.39-0.50]), respectively. Experienced and less experienced MRI observers had good κ [95% CI] (0.70 [0.62-0.78]) and moderate agreement (0.51 [0.41-0.62]), regarding tumor detection, good agreement regarding stromal invasion (0.80 [0.72-0.88] and 0.71 [0.61-0.81]) and parametrial invasion (0.69 [0.61-0.77] and 0.71[0.61-0.81]), respectively.CONCLUSION: The inter-observer agreement was moderate for US, and moderate - good for MRI regarding the assessment of local tumor extension. The level of inter-observer agreement was only associated with experience among US observers regarding parametrial invasion. This article is protected by copyright. All rights reserved.
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- Pavel, M., et al.
(författare)
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Gastroenteropancreatic neuroendocrine neoplasms : ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up
- 2020
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 31:7, s. 844-860
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Tidskriftsartikel (refereegranskat)abstract
- Neuroendocrine neoplasms (NENs) arise from the diffuse neuroendocrine cell system and may occur at many different disease sites. Most frequently, these neoplasms occur in the digestive system, followed by the lung. The term NEN encompasses well-differentiated neuroendocrine tumours (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). NECs represent only 10%–20% of all NENs. The main focus of these guidelines is on sporadic small intestinal (SI)-NENs and pancreatic NENs (Pan-NENs) since these are the most prevalent NENs at advanced disease stages. In general, the management of other gastrointestinal NENs follows the same principles as in SI- or Pan-NENs taking into consideration key features of NENs such as proliferative activity, somatostatin receptor (SSTR) expression, tumour growth rate and extent of the disease.
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- Antoni, Gunnar, et al.
(författare)
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Synthesis of l-2,4-Diamino[4-11C]butyric acid and its use in some In vitro and In vivo tumour models
- 1997
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Ingår i: Nuclear Medicine and Biology. - 0969-8051 .- 1872-9614. ; 24:6, s. 595-601
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Tidskriftsartikel (refereegranskat)abstract
- l-2,4-Diamino[4-11C]butyric acid (DAB) was synthesized by an enzyme catalysed carrier added (0.1 μmol KCN) reaction of hydrogen [11C]cyanide with O-acetyl-l-serine followed by reduction. l-[11C]DAB was obtained with a radiochemical purity higher than 96% and with a decay corrected radiochemical yield of 30–40% within a 32 min reaction time. The enantiomeric excess was 98%. The uptake of l-[11C]DAB was investigated in multicellular aggregates of six different cell lines and animal tumour models. l-[11C]DAB is potentially useful for the assessment of pharmacokinetics of l-DAB in vivo for part of its evaluation as an antitumoural agent, although its use for diagnostic purposes seems limited.
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- Aziz, Q, et al.
(författare)
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Identification of human brain loci processing esophageal sensation using positron emission tomography
- 1997
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Ingår i: Gastroenterology. - 0016-5085 .- 1528-0012. ; 113:1, s. 50-59
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS:Brain loci that process human esophageal sensation remain unidentified. The aim of this study was to identify the brain loci that process nonpainful and painful human esophageal sensation.METHODS:In 8 healthy subjects (7 men; age range, 24-47 years), distal esophageal stimulation was performed by repeatedly inflating a balloon at volumes that produced either no sensation, definite sensation, or pain. Two positron emission tomography scans were performed for each sensation using H2(15)O. Magnetic resonance brain scans were also performed in each subject, and the positron emission tomography data were coregistered with magnetic resonance scans. Analysis of covariance-corrected t images showing the contrasts definite sensation-baseline, pain-baseline, and pain-definite sensation were created.RESULTS:Nonpainful stimulation elicited bilateral activations along the central sulcus, insular cortex, and frontal/parietal operculum (P < 0.01). Painful stimulation produced more intense activations of the same areas and additional activation of the right anterior insular cortex and the anterior cingulate gyrus. Multiple areas of decreased activation were also observed; prominent among these was the right prefrontal cortex, which was inhibited during both nonpainful and painful stimulation.CONCLUSIONS:Esophageal sensation activates bilaterally the insula, primary somatosensory cortex, and operculum. The right anterior insular cortex and anterior cingulate gyrus process esophageal pain.
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- Bergström, Mats, et al.
(författare)
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PET imaging of adrenal cortical tumors with the 11beta-hydroxylase tracer 11C-metomidate
- 2000
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Ingår i: Journal of Nuclear Medicine. - 0161-5505 .- 1535-5667. ; 41:2, s. 275-282
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to evaluate PET with the tracer 11C-metomidate as a method to identify adrenal cortical lesions.METHODS:PET with 11C-metomidate was performed in 15 patients with unilateral adrenal mass confirmed by CT. All patients subsequently underwent surgery, except 2 who underwent biopsy only. The lesions were histopathologically examined and diagnosed as adrenal cortical adenoma (n = 6; 3 nonfunctioning), adrenocortical carcinoma (n = 2), and nodular hyperplasia (n = 1). The remaining were noncortical lesions, including 1 pheochromocytoma, 1 myelolipoma, 2 adrenal cysts, and 2 metastases.RESULTS:All cortical lesions were easily identified because of exceedingly high uptake of 11C-metomidate, whereas the noncortical lesions showed very low uptake. High uptake was also seen in normal adrenal glands and in the stomach. The uptake was intermediate in the liver and low in other abdominal organs. Images obtained immediately after tracer injection displayed high uptake in the renal cortex and spleen. The tracer uptake in the cortical lesions increased throughout the examination. For quantitative evaluation of tracer binding in individual lesions, a model with the splenic radioactivity concentration assigned to represent nonspecific uptake was applied. Values derived with this method, however, did show the same specificity as the simpler standardized uptake value concept, with similar difference observed for cortical versus noncortical lesions.CONCLUSION:PET with 11C-metomidate has the potential to be an attractive method for the characterization of adrenal masses with the ability to discriminate lesions of adrenal cortical origin from noncortical lesions.
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- Bergström, Mats, et al.
(författare)
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PET with [11C]-Metomidate for the Visualization of Adrenocortical Tumors and Discrimination from Other Lesions
- 1999
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Ingår i: Clinical Positron Imaging. - 1095-0397 .- 1878-5751. ; 2:6, s. 339-
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:The purpose of the study was to evaluate the potential role of PET with the adrenocortical-specific tracer 11C-metomidate in the characterization of incidentally found adrenal cortical lesions and in adrenocortical carcinomas.Methods:PET with 11C-metomidate was performed in 15 patients with unilateral adrenal mass confirmed by CT (incidentalomas) and in 9 additional patients with adrenocortical cancer. All incidentalomas subsequently underwent surgery, except 2 subjected to biopsy only. These lesions were histopathologically examined and diagnosed as adrenal cortical adenoma (n = 6; 3 nonfunctioning), adrenocortical carcinoma (n = 2) and nodular hyperplasia (n = 1). The remaining were non-cortical lesions including 1 pheochromocytoma, 1 myelolipoma, 2 adrenal cysts, and 2 metastases.Results:All lesions, except 1, with an adrenocortical origin were easily identified due to exceedingly high uptake of 11C-metomidate, whereas the non-cortical lesions showed very low uptake. The 1 false negative was a cancer that at surgery was found to be extensively necrotic. High uptake was also seen in normal adrenal glands. The tracer uptake kinetics indicated trapping of the tracer in the cortical lesions. For quantitative evaluation of tracer binding in individual lesions, the simple SUV concept was found to be equally accurate as more elaborate kinetic analyses.Conclusion:The patients presented and altogether over 40 PET investigations have demonstrated 11C-metomidate to be an attractive tracer for the characterization of adrenal masses with the ability to discriminate lesions of adrenal cortical origin from non-cortical lesions. Additionally the method allows the assessment of metastases from adrenocortical cancers, and the very high contrast has allowed partial whole-body examinations.
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- Byström, Per, et al.
(författare)
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Early prediction of response to first-line chemotherapy by sequential [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography in patients with advanced colorectal cancer
- 2009
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Ingår i: Annals of Oncology. - : Elsevier BV. - 0923-7534 .- 1569-8041. ; 20:6, s. 1057-1061
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: To evaluate [(18)F]-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET), for early evaluation of response to palliative chemotherapy and for prediction of long-term outcome, in patients with metastatic colorectal cancer (mCRC). PATIENTS AND METHODS: In a randomized trial, patients with mCRC received irinotecan-based combination chemotherapy. FDG-PET was carried out before treatment and after two cycles in 51 patients at two centers. Visual changes in tumor FDG uptake and changes measured semi-automatically, as standard uptake values (SUVs), were compared with radiological response after four and eight cycles. RESULTS: The mean baseline SUV for all tumor lesions per patient was higher in nonresponders than in responders (mean 7.4 versus 5.6, P = 0.02). There was a strong correlation between metabolic response (changes in SUV) and objective response (r = 0.57, P = 0.00001), with a sensitivity of 77% and a specificity of 76%. There was no significant correlation between metabolic response and time to progression (P = 0.5) or overall survival (P = 0.1). CONCLUSIONS: Although metabolic response assessed by FDG-PET reflects radiological tumor volume changes, the sensitivity and specificity are too low to support the routine use of PET in mCRC. Furthermore, PET failed to reflect long-term outcome and can, thus, not be used as surrogate end point for hard endpoint benefit.
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