Maxime Hackx

Université Libre de Bruxelles, Bruxelles, Brussels Capital, Belgium

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Publications (8)23.14 Total impact

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    ABSTRACT: Purpose To determine the effect of bronchodilation on airway indexes reflecting airway disease in patients with chronic obstructive pulmonary disease (COPD) and to determine the minimum number of segmental and subsegmental airways required. Materials and Methods This study was approved by the local ethical committee, and written informed consent was obtained from all subjects. Twenty patients with COPD who had undergone pre- and postbronchodilator pulmonary function tests and computed tomographic (CT) examinations were prospectively included. Eight healthy volunteers underwent two CT examinations. Luminal area and wall thickness (WT) of third- and fourth-generation airways were measured twice by three readers. The percentage of total airway area occupied by the wall and the square root of wall area at an internal perimeter of 10 mm (√WAPi10) were calculated. The effects of pathologic status, session, reader, bronchodilation, and CT examination were assessed by using mixed linear model analyses. The number of airways to measure for a definite percentage error of √WAPi10 was computed by using a bootstrap method. Results There were no significant session, reader, or bronchodilation effects on WT in third-generation airways and √WAPi10 in patients with COPD (P values ranging from .187 to >.999). WT in third-generation airways and √WAPi10 were significantly different in patients with COPD and control subjects (P = .018 and <.001, respectively). Measuring 12 third- or fourth-generation airways ensured a maximal 10% error of √WAPi10. Conclusion WT in third-generation airways and √WAPi10 are not significantly different before and after bronchodilation and are different in patients with COPD and control subjects. Twelve is the minimum number of third- or fourth-generation airways required to ensure a maximal 10% error of √WAPi10. Clinical trial registration no. NCT01142531 (©) RSNA, 2015 Online supplemental material is available for this article.
    Radiology 05/2015; DOI:10.1148/radiol.2015140949 · 6.87 Impact Factor
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    ABSTRACT: To determine the performance of the spine sign in detecting lower chest abnormalities on lateral view. This retrospective study included 200 patients who had undergone lateral view and CT scans of the chest within one week. Two radiologists independently read the lateral views, and a third radiologist, blinded to the aim of the study, read the scans. The spine sign was considered as positive if the progressive increase in lucency of the vertebral bodies was altered. Inter-reader agreement was calculated through K-statistics. Sensitivity, specificity, positive and negative predictive values, and accuracy were calculated as compared to CT. Agreements between readers ranged from 0.12 to 0.68. Positive spine sign could appear in two ways: absent or inversed progressive increase in lucency of the vertebral bodies. Sensitivity, specificity, positive and negative predictive values, and accuracy were respectively, 60 and 70%, 64 and 84%, 91 and 97%, 19 and 29%, and 61 and 72% for each reader (P ranging from 0.026 to 0.196). Abnormalities most frequently associated with positive spine sign were, platelike atelectasis, ground glass opacity, pleural effusion, and consolidation. The spine sign can present as an absent or inversed progressive increase in lucency of the vertebral bodies. It has a moderate sensitivity but a good positive predictive value, so it can be useful especially when it appears as inversed progressive increase in lucency of the vertebral bodies to detect various abnormalities usually identifiable on chest radiographs. Advances in knowledge: On lateral chest radiographs, the spine sign is useful to detect lower chest abnormalities and is related to various underlying abnormalities and is, per se, non-specific.
    The British journal of radiology 04/2015; 88(1050):20140378. DOI:10.1259/bjr.20140378 · 2.03 Impact Factor
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    ABSTRACT: Unlabelled: Abstract Objective: To describe CT features associated with severe exacerbations of Chronic Obstructive Pulmonary Disease (COPD). Materials and methods: In this prospective ethical-committee-approved study, 44 COPD patients (34 men, 10 women, age range 49-83 years) who provided written informed consent were included at the time of hospital admission for severe exacerbation. Pulmonary function tests (PFT) and chest CT scans were performed at admission and after resolution of the episode following a minimum of 4 weeks free of any acute symptom. For each CT scan, two radiologists independently scored 15 features in each lobe and side. CT features and PFT results were compared for exacerbation and control through Mac-Nemar tests and paired t-tests, respectively. Results: Forced expiratory volume in 1 second and vital capacity improved significantly after exacerbation (p = 0.023 and 0.012, respectively). Bronchial wall thickening and lymphadenopathy were graded significantly higher at exacerbation than at control by both readers (p ranging from < 0.001 to 0.028). Other CT features were not observed during exacerbation, or were so only by one reader (p ranging from < 0.001 to 0.928). Conclusion: Only lymphadenopathy and bronchial wall thickening are CT features associated with severe COPD exacerbation, respectively in 25% and 50% of patients. Our findings do not advocate a role for CT in the routine work-up of patients with severe COPD exacerbation.
    COPD Journal of Chronic Obstructive Pulmonary Disease 06/2014; DOI:10.3109/15412555.2014.903916 · 2.67 Impact Factor
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    ABSTRACT: Chronic obstructive pulmonary disease (COPD) is an increasing cause of morbidity and mortality worldwide and results in substantial social and economic burdens. COPD is a heterogeneous disease with both extrapulmonary and pulmonary components. The pulmonary component is characterized by an airflow limitation that is not fully reversible. In the authors' opinion, none of the currently available classifications combining airflow limitation measurements with clinical parameters is sufficient to determine the prognosis and treatment of a particular patient with COPD. With regard to the causes of airflow limitation, CT can be used to quantify the two main contributions to COPD: emphysema, and small airways disease (a narrowing of the airways). CT quantification-with subsequent COPD phenotyping-can contribute to improved patient care, assessment of COPD progression, and identification of severe COPD with increasing risk of mortality. Small airways disease can be quantified through measurements reflecting morphology, quantification of obstruction, and changes in airways walls. This article details these three approaches and concludes with perspectives and directions for further research. © RSNA, 2012.
    Radiology 10/2012; 265(1):34-48. DOI:10.1148/radiol.12111270 · 6.87 Impact Factor
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    ABSTRACT: PURPOSE Variability is a limitation to the incorporation of quantitative CT analysis of airways in COPD patients in daily practice. As bronchodilation minimizes the variability of spirometric measurements in COPD patients, we prospectively tested the hypothesis that post-bronchodilation CT measurements of airways are less variable than pre-bronchodilation measurements. If less variable, post-bronchodilation measurements would thus require considering fewer airways than pre-bronchodilation measurements. METHOD AND MATERIALS This study was approved by our ethical committee and informed consent was obtained. Twenty patients (16 men; mean age, 66 yrs ± 8) with no exacerbation or infection episode in the four previous weeks were included. Pre- and post-bronchodilation CT and PFT were performed on the same day, 48 hours after treatment withholding. With dedicated software, luminal area (LA) and wall thickness (WT) of 3rd and 4th generations airways were measured twice by an observer blinded to the bronchodilation status. The percentage of total airway area occupied by the wall (WA%) and the square root of wall area at an internal perimeter of 10 mm (√WAPi10) were calculated. Mean values and variances of pre- and post-bronchodilation LA, WT, WA%, and √WAPi10 were compared. RESULTS Significant differences between the two reading sessions were observed for LA (P<.001), WT of 4th generation airways (P=.028) and WA% (P<.001), but not for WT of 3rd generation airways (P=.728) or √WAPi10 (P=.162). Mean LA and WA% were respectively higher and lower after bronchodilation than before (P<.001 and <.010, respectively), without difference for WT or √WAPi10 (P=.510 and .906, respectively). There was no difference in variances for LA, WT, and WA% between pre- and post-bronchodilation (P ranging from .120 to .913). CONCLUSION CT is able to measure bronchodilation in COPD patients reflected by increased LA and decreased WA%, but bronchodilation does not reduce measurements variability. √WAPi10 is insensitive to intraobserver measurements errors or bronchodilation status. CLINICAL RELEVANCE/APPLICATION In COPD patients, bronchodilation can be measured by CT but is not an appropriate mean to reduce the number of airways to be measured. √WAPi10 should be preferred to WA% as index of airway dimensions
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
  • Journal of thoracic imaging 11/2011; 26(4):248. DOI:10.1097/RTI.0b013e3182343906 · 1.74 Impact Factor
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    ABSTRACT: Secondary localization of chronic lymphocytic leukemia (CLL) in breast is rare, while concurrent invasive ductal carcinoma and CLL manifesting as a collision tumor in breast is extremely rare. The observation of a CLL infiltration closely associated with a distinct breast neoplasm with the absence of any other localization for the leukemia is an indisputable argument for a relationship between the two diseases. The presence of both tumors is not simply due to chance. This association (CLL and carcinoma) has also been described in other organs. Hereafter, we report a second case of an 80 year-old woman in whom a leukemic infiltrate was confined to the region immediately surrounding poorly differentiated primary breast carcinoma, and we will discuss the association between CLL and carcinoma.
    Pathology - Research and Practice 06/2011; 207(8):514-7. DOI:10.1016/j.prp.2011.05.007 · 1.40 Impact Factor
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    ABSTRACT: The clinical classification of nephrotic syndrome (NS) is based on age at presentation. However, this classification is arbitrary because the majority of early onset NS has a genetic origin and has a widespread age of onset (from fetal life to several years). The aims of this review are to illustrate the knowledge accumulated on congenital nephrotic syndrome (CNS) in terms of genetics, classification, findings at histology and US-based on a review of the literature.
    Pediatric Radiology 01/2011; 41(1):76-81. DOI:10.1007/s00247-010-1793-5 · 1.57 Impact Factor

Publication Stats

21 Citations
23.14 Total Impact Points


  • 2012–2015
    • Université Libre de Bruxelles
      • Department of Radiology
      Bruxelles, Brussels Capital, Belgium
  • 2011
    • Vrije Universiteit Brussel
      • Department of Pathology
      Bruxelles, Brussels Capital, Belgium
    • University Hospital Brussels
      Bruxelles, Brussels Capital Region, Belgium