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Papers by Catherine Roy

Hôtel-Dieu de Lévis is a 349-bed acute-care university teaching hospital located in Quebec, Canad... more Hôtel-Dieu de Lévis is a 349-bed acute-care university teaching hospital located in Quebec, Canada. Since 2003, it has participated in a provincial surveillance program monitoring nosocomial infections initiated by the Institut national de santé publique du Québec (INSPQ) [1-3]. Beginning in 2008, Hôtel-Dieu de Lévis observed an increased incidence in Clostridium difficile infections, higher than the Quebec provincial average (Figure 1). Another critical period for the hospital occurred in 2012-2013, during which 104 documented cases of Clostridium difficile infection were diagnosed, at a rate of 13.1 for 10,000 patient-days. The provincial rate was 7.3. This article presents the organization’s experience in the management of these infections.

Journal of Clinical Medicine

Objectives: The image quality of an Ultra-Low-Dose (ULD) chest CT depends on the patient’s morpho... more Objectives: The image quality of an Ultra-Low-Dose (ULD) chest CT depends on the patient’s morphotype. We hypothesize that there is a threshold beyond which the diagnostic performance of a ULD chest CT is too degraded. This work assesses the influence of morphotype (Body Mass Index BMI, Maximum Transverse Chest Diameter MTCD and gender) on image quality and the diagnostic performance of a ULD chest CT. Methods: A total of 170 patients from three prior prospective monocentric studies were retrospectively included. Renewal of consent was waived by our IRB. All the patients underwent two consecutive unenhanced chest CT acquisitions with a full dose (120 kV, automated tube current modulation) and a ULD (135 kV, fixed tube current at 10 mA). Image noise, subjective image quality and diagnostic performance for nine predefined lung parenchyma lesions were assessed by two independent readers, and correlations with the patient’s morphotype were sought. Results: The mean BMI was 26.6 ± 5.3; 2...

Radiology and Diagnostic Imaging

Purpose: To evaluate the best protocol to be used in WV mode for the abdominopelvic region in ter... more Purpose: To evaluate the best protocol to be used in WV mode for the abdominopelvic region in terms of radiation dose and image quality by comparison with the helical mode. Methods and materials: This study was performed on a 320 x 0.5 mm detector row CT unit. By using several simulations on topograms data and phantoms analysis, we registered CTDIvol. Then, a clinical study on CTUrography was performed, each patient being its own standard. Results: The collimation of 10 cm (200 x 0.5 mm) with 5 volumes had the lowest CTDIvol. This can be explained by several physical phenomena. In the clinical study, the average radiation dose reduction was found to be at 44.03% ± 0.36% (p<0.001). Concerning the qualitative evaluation of the stitching of different volumes and the overall image quality, it was found excellent. Conclusion: Wide Volume CT scanning using 5 volumes of 10cm (200x0.5mm) significantly reduces the radiation dose with an excellent image quality.

Radiology and Diagnostic Imaging, 2017

EClinicalMedicine

Background Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensit... more Background Iodinated and gadolinium-based contrast media (ICM; GBCM) induce immediate hypersensitivity (IH) reactions. Differentiating allergic from non-allergic IH is crucial; allergy contraindicates the culprit agent for life. We studied frequency of allergic IH among ICM or GBCM reactors. Methods Patients were recruited in 31 hospitals between 2005 and 2009. Clinical symptoms, plasma histamine and tryptase concentrations and skin tests were recorded. Allergic IH was diagnosed by intradermal tests (IDT) with the culprit CM diluted 1:10, “potentially allergic” IH by positive IDT with pure CM, and non-allergic IH by negative IDT. Findings Among 245 skin-tested patients (ICM = 209; GBCM = 36), allergic IH to ICM was identified in 41 (19.6%) and to GBCM in 10 (27.8%). Skin cross-reactivity was observed in 11 patients with ICM (26.8%) and 5 with GBCM (50%). Allergy frequency increased with clinical severity and histamine and tryptase concentrations (p < 0.0001). Cardiovascular signs were strongly associated with allergy. Non-allergic IH was observed in 152 patients (62%) (ICM:134; GBCM:18). Severity grade was lower (p < 0.0001) and reaction delay longer (11.6 vs 5.6 min; p < 0.001). Potentially allergic IH was diagnosed in 42 patients (17.1%) (ICM:34; GBCM:8). The delay, severity grade, and mediator release were intermediate between the two other groups. Interpretation Allergic IH accounted for < 10% of cutaneous reactions, and > 50% of life-threatening ones. GBCM and ICM triggered comparable IH reactions in frequency and severity. Cross-reactivity was frequent, especially for GBCM. We propose considering skin testing with pure contrast agent, as it is more sensitive than the usual 1:10 dilution criteria.

Journal de Radiologie

Objectifs Interet et place de l’IRM dans l’exploration de la pathologie testiculaire en complemen... more Objectifs Interet et place de l’IRM dans l’exploration de la pathologie testiculaire en complement de l’echographie-Doppler. Materiels et methodes Etude retrospective de 15 cas de contexte echo-clinique incertain sur une periode de 2 ans. Des sequences axiales et coronales ponderees en Tl, T2 et Tl Fatsat avec injection de Gadolinium toutes realisees avec antenne de surface ont constitue le protocole de routine de l’IRM scrotale. La confrontation chirurgicale a ete realisee pour 8 cas et un suivi evolutif pour 7 cas. Resultats Sur des arguments morphologiques et de prise de contraste, l’IRM a permis une bonne differenciation entre les lesions benignes et les masses tissulaires testiculaires et extra-testiculaires ainsi qu’une meilleure analyse du canal inguinal. Conclusion Le recours a l’IRM testiculaire est de plus en plus rapporte en litterature. En depit de son cout et de son accessibilite, l’IRM scrotale reste une excellente methode d’imagerie indiquee pour les cas douteux en echographie.

Journal of orthopaedic trauma, 2018

To characterize the type and magnitude of lower extremity physical performance deficits in milita... more To characterize the type and magnitude of lower extremity physical performance deficits in military service members who have undergone rehabilitation after limb salvage or transtibial amputation. Cross-sectional prospective. Level I trauma military medical and rehabilitation center. Service members with lower extremity trauma resulting in limb salvage (n = 20) or unilateral transtibial amputation (n = 14) compared with uninjured actively training service members (n = 123). Control participants and individuals with amputation were tested during a single session. Participants with limb salvage were tested with and without the use of a custom carbon fiber orthosis. Physical performance as measured using four-square step, sit-to-stand 5 times, and timed stair ascent tests. Secondary outcomes included the associations between these lower extremity activity measures to determine the interrelationship of activity limitations. The ability of service members to rapidly ascend stairs, a deman...

Journal of minimally invasive gynecology, Jan 5, 2018

To describe a laparoscopic technique for the resection of deep endometriosis, treating the three ... more To describe a laparoscopic technique for the resection of deep endometriosis, treating the three compartments. Educational video SETTING: Tertiary referral center in Strasbourg, France PATIENTS: This is the case of a 37-year-old primiparous woman. Her main symptoms included dysmenorrhea and dyspareunia associated with pollakiuria and macroscopic menstrual hematuria (with emission of endometriotic tissue on analysis). She also complained of dyschezia. The MRI revealed an endometriotic nodule in the vesicouterine space with an involvement of the anterior wall of the uterus and a suspicion of bladder adenomyosis. There are lateral spicules attracting the ovaries towards the midline and an infiltration of the round ligaments and nodules related to the rectovaginal space's endometriosis. A possible invasion is noted underneath the rectal mucosa. The patient wants to preserve her fertility. Adenomyomectomy, partial cystectomy, and bowel resection. Fertility preservation is mandatory d...

Journal of magnetic resonance imaging : JMRI, Jan 20, 2017

Magnetic resonance imaging (MRI) tissue signal is modulated by magnetization transfer (MT) phenom... more Magnetic resonance imaging (MRI) tissue signal is modulated by magnetization transfer (MT) phenomena, intrinsically induced by balanced steady-state free precession (bSSFP) imaging. To investigate the possible value of such a MT-like bSSFP approach in two clinical settings involving focal myocardial lesions highligthed by late gadolinium enhancement (LGE+): edema induced by recent myocardial infarction (MI) and fibrotic scar related to chronic infarction. Population: 48 LGE + patients were studied: 26 with recent MI, 22 with chronic MI. 20 LGE-normal subjects were considered the control group. Field strength/sequence: Navigator-based short axis 3D-bSSFP sequences with 20° and 90° excitation flip angles were acquired (1.5T). Pixel-wise normalized MT Ratio (nMTR) parametric images were calculated according to: nMTR = 100*(S20 -S90 *k)/S20 , with S20 and S90 signal intensity in 20° and 90° flip angle images and k = Blood20 /Blood90 as a normalization ratio. Statistical tests: analysis ...

Annals of vascular surgery, Jan 4, 2017

With the steady increase of endovascular procedures involving the aortic arch (AA), an actual dep... more With the steady increase of endovascular procedures involving the aortic arch (AA), an actual depiction of its anatomy has become mandatory. It has also become necessary to evaluate the natural evolution of the AA morphology as part of the evaluation of endovascular devices durability. The objective of this study was to perform a morphological and anatomical study of the AA and of the supra aortic trunks (SAT) in healthy patients, with an evaluation of their evolution with time, with a specific orientation applied to endovascular therapies of the AA. Sixty-one patients (31 men, mean age 50.8 [18-82]) with a normal anatomy were included in the study. Measurements included the diameters of the AA and SAT in 17 locations, their distance and angulation based on computed tomography angiography data. Statistical analysis focused on descriptive statistics, differences between genders, as well as correlations with age. Aortic diameters (mean ± SD) were 29.5 ± 3.9 mm at the ascending aorta, ...

European Journal of Radiology, 2017

To assess that transrectal ultrasound guidance (TRUS) targeted biopsies (TB) aimed with an easy t... more To assess that transrectal ultrasound guidance (TRUS) targeted biopsies (TB) aimed with an easy to use electronic real-time fusion registration device have a higher rate of prostate cancer (PC) detection than standard biopsies (SB). This prospective study included 130 patients referred for TRUS biopsies after suspicious MRI. They underwent 16-core SB and 2 to 3 cores in each MRI suspicious area, using a fusion software. We noted SB and TB positivity for PC and Gleason score (GS). We used the McNemar test to compare SB and TB, with a statistical significance p&amp;amp;amp;lt;0.05. Among 130 patients, 68.5% had PC. Additional time due to the fusion registration was 3.3 min. One hundred fifteen patients (88.4%) had pathological findings on the histological analysis (prostate cancer n=89, others n=26). TB diagnosed PC in 75 patients with negative SB. Positivity rate for PC was significantly higher for TB than SB (p=0.03). Among highly suspicious MRI lesions, detection rate of histological abnormalities using SB and TB was 96% with 79.7% of PC. Most PC that TB diagnosed alone were clinically significant (86.3%). TRUS biopsies performed with a simple MRI and US electronic fusion is an unrestrainedly method to increase PC diagnosis.

The international journal of cardiovascular imaging, 2016

The purpose of this work was to evaluate CMR T1 and T2 mapping sequences in patients with intraca... more The purpose of this work was to evaluate CMR T1 and T2 mapping sequences in patients with intracardiac thrombi and masses in order to assess T1 and T2 relaxometry usefulness and to allow better etiological diagnosis. This observational study of patients scheduled for routine CMR was performed from September 2014 to August 2015. All patients referred to our department for a 1.5 T CMR were screened to participate. T1 mapping were acquired before and after Gadolinium injection; T2 mapping images were obtained before injection. 41 patients were included. 22 presented with cardiac thrombi and 19 with cardiac masses. The native T1 of thrombi was 1037 ± 152 ms (vs 1032 ± 39 ms for myocardium, p = 0.88; vs 1565 ± 88 ms for blood pool, p < 0.0001). T2 were 74 ± 13 ms (vs 51 ± 3 ms for myocardium, p < 0.0001; vs 170 ± 32 ms for blood pool, p < 0.0001). Recent thrombi had a native T1 shorter than old thrombi (911 ± 177 vs 1169 ± 107 ms, p = 0.01). The masses having a shorter T1 than t...

PLOS ONE, 2016

Objectives To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on ... more Objectives To compare cine MR b-TFE sequences acquired before and after gadolinium injection, on a 3T scanner with a parallel RF transmission technique in order to potentially improve scanning time efficiency when evaluating LV function.

International Journal of Cardiology, 2016

Article history: Received 3 June 2016 Accepted 9 July 2016 Available online 11 July 2016 T1 and T... more Article history: Received 3 June 2016 Accepted 9 July 2016 Available online 11 July 2016 T1 and T2 mapping in mass revealed low T1 (370 ms vs 1050 ms in the remote LV lateral myocardium) and T2 values (43 ms vs 50 ms in the remote LV lateral myocardium) (Fig. 1C, D, E). Contrast technique showed no late gadolinium enhancement (LGE) in themass itself except at its periphery (Fig. 1F). Therewas apical trans-mural LGE, but no LGE of ischemic or non-ischemic distribution in the over-all IVS wall (Fig. 1F).