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Inter-observer Variability Analysis of Automatic Lung Delineation in Normal and Disease Patients

Saba L, Than JC, Noor NM, Rijal OM, Kassim RM, Yunus A, et al.

J Med Syst, 2016 Jun;40(6):142.
PMID: 27114353 DOI: 10.1007/s10916-016-0504-7

Human interaction has become almost mandatory for an automated medical system wishing to be accepted by clinical regulatory agencies such as Food and Drug Administration. Since this interaction causes variability in the gathered data, the inter-observer and intra-observer variability must be analyzed in order to validate the accuracy of the system. This study focuses on the variability from different observers that interact with an automated lung delineation system that relies on human interaction in the form of delineation of the lung borders. The database consists of High Resolution Computed Tomography (HRCT): 15 normal and 81 diseased patients' images taken retrospectively at five levels per patient. Three observers manually delineated the lungs borders independently and using software called ImgTracer™ (AtheroPoint™, Roseville, CA, USA) to delineate the lung boundaries in all five levels of 3-D lung volume. The three observers consisted of Observer-1: lesser experienced novice tracer who is a resident in radiology under the guidance of radiologist, whereas Observer-2 and Observer-3 are lung image scientists trained by lung radiologist and biomedical imaging scientist and experts. The inter-observer variability can be shown by comparing each observer's tracings to the automated delineation and also by comparing each manual tracing of the observers with one another. The normality of the tracings was tested using D'Agostino-Pearson test and all observers tracings showed a normal P-value higher than 0.05. The analysis of variance (ANOVA) test between three observers and automated showed a P-value higher than 0.89 and 0.81 for the right lung (RL) and left lung (LL), respectively. The performance of the automated system was evaluated using Dice Similarity Coefficient (DSC), Jaccard Index (JI) and Hausdorff (HD) Distance measures. Although, Observer-1 has lesser experience compared to Obsever-2 and Obsever-3, the Observer Deterioration Factor (ODF) shows that Observer-1 has less than 10% difference compared to the other two, which is under acceptable range as per our analysis. To compare between observers, this study used regression plots, Bland-Altman plots, two tailed T-test, Mann-Whiney, Chi-Squared tests which showed the following P-values for RL and LL: (i) Observer-1 and Observer-3 were: 0.55, 0.48, 0.29 for RL and 0.55, 0.59, 0.29 for LL; (ii) Observer-1 and Observer-2 were: 0.57, 0.50, 0.29 for RL and 0.54, 0.59, 0.29 for LL; (iii) Observer-2 and Observer-3 were: 0.98, 0.99, 0.29 for RL and 0.99, 0.99, 0.29 for LL. Further, CC and R-squared coefficients were computed between observers which came out to be 0.9 for RL and LL. All three observers however manage to show the feature that diseased lungs are smaller than normal lungs in terms of area.
Extracranial internal carotid artery calcium volume measurement using computer tomography

Baradaran H, Ng CR, Gupta A, Noor NM, Al-Dasuqi KW, Mtui EE, et al.

Int Angiol, 2017 Oct;36(5):445-461.
PMID: 28541017 DOI: 10.23736/S0392-9590.17.03811-1

BACKGROUND: The extent of calcium volume in the carotid arteries of contrast-based computer tomography (CT) is a valuable indicator of stroke risk. This study presents an automated, simple and fast calcium volume computation system. Since the high contrast agent can sometimes obscure the presence of calcium in the CT slices, it is therefore necessary to identify these slices before the corrected volume can be estimated.
METHODS: The system typically consists of segmenting the calcium region from the CT scan into slices based on Hounsfield Unit-based threshold, and subsequently computing the summation of the calcium areas in each slice. However, when the carotid volume has intermittently higher concentration of contrast agent, a dependable approach is adapted to correct the calcium region using the neighboring slices, thereby estimating the correct volume. Furthermore, mitigation is provided following the regulatory constraints by changing the system to semi-automated criteria as a fall back solution. We evaluate the automated and semi-automated techniques using completely manual calcium volumes computed based on the manual tracings by the neuroradiologist.
RESULTS: A total of 64 patients with calcified plaque in the internal carotid artery were analyzed. Using the above algorithm, our automated and semi-automated system yields correlation coefficients (CC) of 0.89 and 0.96 against first manual readings and 0.90 and 0.96 against second manual readings, respectively. Using the t-test, there was no significant difference between the automated and semi-automated methods against manual. The intra-observer reliability was excellent with CC 0.98.
CONCLUSIONS: Compared to automated method, the semi-automated method for calcium volume is acceptable and closer to manual strategy for calcium volume. Further work evaluating and confirming the performance of our semi-automated protocol is now warranted.
A retrospective record review of tuberculous infections in rheumatoid arthritis patients on biologics in Malaysia

Nor Hashimah AMN, Lim AL, Mohd Zain M, Gun SC, Mohd Isa L, Chong HC, et al.

Med J Malaysia, 2023 Dec;78(7):870-875.
PMID: 38159920

INTRODUCTION: The aim of this study was to analyse the clinical characteristics of patients with rheumatoid arthritis receiving biologics therapy and investigate the association between types of biologics and tuberculosis (TB) infections in 13 tertiary hospitals in Malaysia.
MATERIALS AND METHODS: This was a retrospective study that included all RA patients receiving biologics therapy in 13 tertiary hospitals in Malaysia from January 2008 to December 2018.
RESULTS: We had 735 RA patients who received biologics therapy. Twenty-one of the 735 patients were diagnosed with TB infection after treatment with biologics. The calculated prevalence of TB infection in RA patients treated with biologics was 2.9% (29 per 1000 patients). Four groups of biologics were used in our patient cohort: monoclonal TNF inhibitors, etanercept, tocilizumab, and rituximab, with monoclonal TNF inhibitors being the most commonly used biologic. The median duration of biologics therapy before the diagnosis of TB was 8 months. 75% of patients had at least one co-morbidity and all patients had at least one ongoing cDMARD therapy at the time of TB diagnosis. More than half of the patients were on steroid therapy with an average prednisolone dose of 5 mg daily.
CONCLUSION: Although the study population and data were limited, this study illustrates the spectrum of TB infections in RA patients receiving biologics and potential risk factors associated with biologics therapy in Malaysia.
A hierarchical cluster analysis for clinical profiling of tofacitinib treatment response in patients with rheumatoid arthritis

Janahiraman S, Shahril NS, Jayaraj VJ, Ch'ng S, Eow LH, Mageswaren E, et al.

Clin Rheumatol, 2024 Aug;43(8):2489-2501.
PMID: 38922551 DOI: 10.1007/s10067-024-07035-x

Tofacitinib is the first oral JAK inhibitor approved for treating rheumatoid arthritis (RA). To enhance our understanding of tofacitinib drug response, we used hierarchical clustering to analyse the profiles of patient who responded to the treatment in a real-world setting. Patients who commenced on tofacitinib treatment were selected from 12 major rheumatology centres in Malaysia. The aim was to assess their response to tofacitinib defined as achieving DAS28-CRP/ESR ≤ 3.2 and DAS28 improvement > 1.2 at 12 weeks. A hierarchical clustering analysis was performed using sociodemographic and clinical parameters at baseline. All 163 RA patients were divided into three clusters (Clusters 1, 2 and 3) based on specific clinical factors at baseline including bone erosion, antibody positivity, disease activity and anaemia status. Cluster 1 consisted of RA patients without bone erosion, antibody negative, low baseline disease activity measure and absence of anaemia. Cluster 2 comprised of patients without bone erosion, RF positivity, anti-CCP negativity, moderate to high baseline disease activity score and absence of anaemia. Cluster 3 patients had bone erosion, antibody positivity, high baseline disease activity and anaemia. The response rates to tofacitinib varied among the clusters: Cluster 1 had a 79% response rate, Cluster 2 had a 66% response rate, and Cluster 3 had a 36% response rate. The differences in response rates between the three clusters were found to be statistically significant. This cluster analysis study indicates that patients who are seronegative and have low disease activity, absence of bone erosion and no signs of anaemia may have a higher likelihood of benefiting from tofacitinib therapy. By identifying clinical profiles that respond to tofacitinib treatment, we can improve treatment stratification yielding significant benefits and better health outcomes for individuals with RA.