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How reliable are ADC measurements? A phantom and clinical study of cervical lymph nodes.

ABSTRACT: OBJECTIVE:To assess the reliability of ADC measurements in vitro and in cervical lymph nodes of healthy volunteers. METHODS:We used a GE 1.5 T MRI scanner and a first ice-water phantom according to recommendations released by the Quantitative Imaging Biomarker Alliance (QIBA) for assessing ADC against reference values. We analysed the target size effect by using a second phantom made of six inserted spheres with diameters ranging from 10 to 37 mm. Thirteen healthy volunteers were also scanned to assess the inter- and intra-observer reproducibility of volumetric ADC measurements of cervical lymph nodes. RESULTS:On the ice-water phantom, the error in ADC measurements was less than 4.3 %. The spatial bias due to the non-linearity of gradient fields was found to be 24 % at 8 cm from the isocentre. ADC measure reliability decreased when addressing small targets due to partial volume effects (up to 12.8 %). The mean ADC value of cervical lymph nodes was 0.87.10-3 ± 0.12.10-3 mm2/s with a good intra-observer reliability. Inter-observer reproducibility featured a bias of -5.5 % due to segmentation issues. CONCLUSION:ADC is a potentially important imaging biomarker in oncology; however, variability issues preclude its broader adoption. Reliable use of ADC requires technical advances and systematic quality control. KEY POINTS:• ADC is a promising quantitative imaging biomarker. • ADC has a fair inter-reader variability and good intra-reader variability. • Partial volume effect, post-processing software and non-linearity of scanners are limiting factors. • No threshold values for detecting cervical lymph node malignancy can be drawn.

SUBMITTER: Moreau B

PROVIDER: S-EPMC6028847 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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How reliable are ADC measurements? A phantom and clinical study of cervical lymph nodes.

Moreau Bastien B Iannessi Antoine A Hoog Christopher C Beaumont Hubert H

European radiology 20180223 8

<h4>Objective</h4>To assess the reliability of ADC measurements in vitro and in cervical lymph nodes of healthy volunteers.<h4>Methods</h4>We used a GE 1.5 T MRI scanner and a first ice-water phantom according to recommendations released by the Quantitative Imaging Biomarker Alliance (QIBA) for assessing ADC against reference values. We analysed the target size effect by using a second phantom made of six inserted spheres with diameters ranging from 10 to 37 mm. Thirteen healthy volunteers were ...[more]

PMID: 29476218

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Project description:BackgroundUnderlying coinfections may complicate infectious disease states but commonly go unnoticed because an a priori clinical suspicion is usually required so they can be detected via targeted diagnostic tools. Shotgun metagenomics is a broad diagnostic tool that can be useful for identifying multiple microbes simultaneously especially if coupled with lymph node aspirates, a clinical matrix known to house disparate pathogens. The objective of this study was to analyze the utility of this unconventional diagnostic approach (shotgun metagenomics) using clinical samples from human tularemia cases as a test model. Tularemia, caused by the bacterium Francisella tularensis, is an emerging infectious disease in Turkey. This disease commonly manifests as swelling of the lymph nodes nearest to the entry of infection. Because swollen cervical nodes are observed from many different types of human infections we used these clinical sample types to analyze the utility of shotgun metagenomics.MethodsWe conducted an unbiased molecular survey using shotgun metagenomics sequencing of DNA extracts from fine-needle aspirates of neck lymph nodes from eight tularemia patients who displayed protracted symptoms. The resulting metagenomics data were searched for microbial sequences (bacterial and viral).ResultsF. tularensis sequences were detected in all samples. In addition, we detected DNA of other known pathogens in three patients. Both Hepatitis B virus (HBV) and Human Parvovirus B-19 were detected in one individual and Human Parvovirus B-19 alone was detected in two other individuals. Subsequent PCR coupled with Sanger sequencing verified the metagenomics results. The HBV status was independently confirmed via serological diagnostics, despite evading notice during the initial assessment.ConclusionOur data highlight that shotgun metagenomics of fine-needle lymph node aspirates is a promising clinical diagnostic strategy to identify coinfections. Given the feasibility of the diagnostic approach demonstrated here, further steps to promote integration of this type of diagnostic capability into mainstream clinical practice are warranted.

Project description:Cervical lymph nodes (CLN) are the first lymph nodes encountered by material taking the oral route. To study their role in orally acquired infections, we analyzed 307 patients of up to 14 years treated in the university clinic of Skopje, Macedonia, for brucellosis, a zoonotic bacterial disease frequently acquired by ingestion of contaminated dairy products. From these children, 36% had lymphadenopathy. Among orally infected children, lymphadenopathy with CLN being the only lymph nodes affected was significantly more frequent as compared to those infected by contact with animals (83% vs. 63%), suggesting a possible involvement of CLN during orally acquired human brucellosis. Using a murine model where bacteria are delivered into the oral cavity, we show that Brucella quickly and selectively colonize the CLN where they proliferate and persist over long periods of time for up to 50 days post-infection. A similar efficient though less specific drainage to CLN was found for Brucella, Salmonella typhimurium and fluorescent microspheres delivered by gavage, a pathway likely representing a mixed infection mode of intragastric and oral infection, suggesting a central pathway of drained material. Microspheres as well as bacteria drained to CLN predominately reside in cells expressing CD68 and no or low levels of CD11c. Even though no systemic response could be detected, Brucella induced a locally restricted inflammatory reaction with increased expression levels of interferon γ, interleukin (IL)-6, IL-12, granzyme B and a delayed induction of Nos2. Inflammation led to pronounced lymphadenopathy, infiltration of macrophages/monocytes expressing high levels of major histocompatibility complex II and to formation of epitheloid granulomas. Together, these results highlight the role of CLN in oral infections as both, an initial and efficient trap for bacterial invaders and as possible reservoir for chronic pathogens. They likewise cast a new light on the significance of oral routes for means of vaccination.

Project description:Purpose: To investigate N-staging Assessment of pretreatment Shear wave elastrography (SWE) in small cervical lymph nodes (0. 5 cm ? maximum diameter < 1 cm, intact capsule, no central necrosis, sCLNs) in nasopharyngeal carcinoma (NPC) patients. Methods: Pathological biopsy proven 28 NPC patients with sCLNs shown in pretreatment magnetic resonance (MR) images and 40 target lymph nodes were enrolled. All target lymph nodes were divided into metastasis and benign lymph node groups according to pathology. SWE was used to exam the real time SWE imaging of each target lymph nodes before conducting ultrasonography guided fine needle biopsy. The minimum (Emin), maximum (Emax), and mean (Emean) elasticity indices (kPa) of target lymph nodes were recorded. The SWE examination was repeated three times for the same target lymph node and each elasticity indices for statistic was determined by average of three measurements. SPSS 21.0 statistics software is used for statistical analysis. The receiver operating characteristic (ROC) curve was performed to obtain the cutoff value of elasticity indices of metastatic sCLNs. Statistical significance was assumed when the P < 0.05. Results: Nine lymph nodes were metastatic and 31 were benign. The Emin, Emax, and Emean of benign group were 8.15 ± 6.12, 25.05 ± 12.37, and 16.05 ± 8.29 kPa, respectively; Emin, Emax, and Emean of metastasis group were 11.5 ± 6.17, 41.38 ± 17.87, and 23.48 ± 6.50 kPa, respectively. The difference of the Emax and Emean between metastasis and benign group were statistically significant (P = 0.003 and 0.018). The area under the ROC curve of Emin, Emax, and Emean of metastasis lymph node were 0.685 (P = 0.095), 0.785 (P = 0.010), and 0.765 (P = 0.017), respectively. Emax of 27 kPa and Emean of 17 kPa were taken as the cutoff value of diagnosis for metastasis sCLNs: the sensitivity, specificity, and accuracy were 77.8 and 100%, 71.0 and 61.3%, 75.0 and 70.0%, respectively. Conclusions: Pretreatment SWE has high accuracy in evaluating the sCLNs in NPC patients and is helpful for accurate N-staging and survival prognosis. It can be used as a clinical supplementary examination.

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How reliable are ADC measurements? A phantom and clinical study of cervical lymph nodes.

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How reliable are ADC measurements? A phantom and clinical study of cervical lymph nodes.

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