Biomedical subjects

P A Grenier

Publications and source records attributed to P A Grenier.

7 recordsLinked to original sources

PubMed2006

Quantification of bronchial dimensions at MDCT using dedicated software.

This study aimed to assess the feasibility of quantification of bronchial dimensions at MDCT using dedicated software (BronCare). We evaluated the reliability of the software to segment the airways and defined criteria ensuring accurate measurements. BronCare was applied on two successive examinations in 10 mild asthmatic patients. Acquisitions were performed at pneumotachographically controlled lung volume (65% TLC), with reconstructions focused on the right lung base. Five validation criteria were imposed: (1) bronchus type: segmental and subsegmental; (2) lumen area (LA)>4 mm2; (3) bronchus length (Lg) > 7 mm; (4) confidence index - giving the percentage of the bronchus not abutted by a vessel - (CI) >55% for validation of wall area (WA) and (5) a minimum of 10 contiguous cross-sectional images fulfilling the criteria. A complete segmentation procedure on both acquisitions made possible an evaluation of LA and WA in 174/223 (78%) and 171/174 (98%) of bronchi, respectively. The validation criteria were met for 56/69 (81%) and for 16/69 (23%) of segmental bronchi and for 73/102 (72%) and 58/102 (57%) of subsegmental bronchi, for LA and WA, respectively. In conclusion, BronCare is reliable to segment the airways in clinical practice. The proposed criteria seem appropriate to select bronchi candidates for measurement.

Asthma↗

PubMed2000

MR arthrography of the hip: normal intra-articular structures and common disorders.

This pictorial review illustrates the anatomical features of normal intra-articular components of the hip and their common disorders on MR arthrography. On T1-weighted MR arthrograms, the normal contrast-filled joint cavity shows a homogeneous high signal intensity. Normal acetabular labrum appears as a well-delineated triangle showing a low signal intensity, surrounded by contrast material in the perilabral recess. Intra-articular paramagnetic contrast outlines labral tears, loose bodies, communicating labral cysts and cartilage lesions (traumatic tears, focal defects, degenerative fissures and thinning), and improves their detection. Overall, MR arthrography enables accurate detection and staging of hip intra-articular structure abnormalities.

Hip Joint↗

PubMed2000

Diaphragm and chest wall: assessment of the inspiratory pump with MR imaging-preliminary observations.

Magnetic resonance (MR) imaging of the thorax with three-dimensional (3D) reconstruction and functional quantification was evaluated as a tool for structure-function evaluation of chest-wall mechanics. Good agreement was found between the corresponding spirometric and MR imaging values of lung volumes. Fast MR imaging of the thorax with 3D reconstruction should improve the ability to evaluate the inspiratory pump in clinical and research investigations.

Adult↗

PubMed2000

Transjugular versus percutaneous renal biopsy for the diagnosis of parenchymal disease: comparison of sampling effectiveness and complications.

PURPOSE: To compare the effectiveness and safety of transjugular renal biopsy with those of percutaneous renal biopsy for diagnosis of renal parenchymal disease. MATERIALS AND METHODS: Results and complications of 400 consecutive transjugular renal biopsies performed between 1993 and 1998 with a modified Colapinto transjugular hepatic biopsy system were compared retrospectively with those of 400 percutaneous renal biopsies performed during the same period. Transjugular renal biopsy was associated with 14 cardiac and 35 hepatic biopsies. Number of glomeruli per tissue core, adequacy of tissue core for histopathologic diagnosis, and rate and severity of complications were analyzed. RESULTS: Renal tissue was obtained with percutaneous renal biopsy in 382 (95.5%) of 400 patients and with transjugular renal biopsy in 383 (95.8%) of 400 patients. The mean numbers of intact glomeruli per tissue core with optical microscopy were 11.2 +/- 7.7 (SD) and 9.8 +/- 7.6 for percutaneous renal biopsy and transjugular renal biopsy, respectively. With immunofluorescent microscopy, the mean numbers were 6.4 +/- 5.3 and 4.6 +/- 4.6 for percutaneous renal biopsy and transjugular renal biopsy, respectively. Tissue cores were adequate for histopathologic diagnosis in 98.2% with both techniques. Major complications occurred with transjugular renal biopsy in four patients and with percutaneous renal biopsy in three patients. CONCLUSION: Use of transjugular renal biopsy provides diagnostic yield and safety similar to those of percutaneous renal biopsy and allows multiorgan biopsy during the same procedure. It can be recommended in patients with percutaneous renal biopsy contraindication or failure.

Adult↗

PubMed2000

Evaluation of air trapping at CT: comparison of continuous-versus suspended-expiration CT techniques.

PURPOSE: To compare thin-section computed tomographic (CT) scans obtained during suspended end expiration with helical CT scans obtained during continuous expiration for the assessment of air trapping. MATERIALS AND METHODS: Forty-nine patients with an airway disease were examined with suspended-end-expiration CT after a 6-8-second expiratory maneuver, which was followed with continuous-expiration CT during a 10-second expiratory maneuver. The extent of expiratory air-trapping areas was calculated by two observers by using a semiquantitative grid score. The relative decrease in attenuation in the areas of air trapping was evaluated with a visual continuous-scale score. RESULTS: Air trapping was noted in 36 and 35 patients with continuous-expiration CT and with suspended-end-inspiration CT, respectively. The extents of and relative attenuation decreases in air-trapping areas in patients with air-trapping areas on at least one expiratory CT scan increased significantly in scans obtained with continuous-expiration CT compared with those obtained with suspended-end-expiration CT, respectively, with mean extent scores of 0.24 +/- 0.20 (SD) and 0.18 +/- 0.20 (paired t test, P: =.001) respectively, and with mean relative contrast decrease scores of 0.35 +/- 0.23 and 0.27 +/- 0.23 (paired t test, P: =.007), respectively. CONCLUSION: When suspended-end-expiration CT images are ambiguous, complementary continuous-expiration CT can be used to improve the conspicuity and apparent extent of air trapping.

Adolescent↗

PubMed1998

Spiral computed tomographic scanning and magnetic resonance angiography for the diagnosis of pulmonary embolism.

PURPOSE: To compare prospectively the accuracy of spiral computed tomography (CT) with that of ventilation-perfusion scintigraphy for diagnosing pulmonary embolism. MATERIALS AND METHODS: Within 48 hours of presentation, 142 patients suspected of having pulmonary embolism underwent spiral CT, scintigraphy, and (when indicated) pulmonary angiography. Pulmonary angiography was attempted if interpretations of spiral CT scans and of scintigrams were discordant or indeterminate and intermediate-probability, respectively. RESULTS: In the 139 patients who completed the study, interpretations of spiral CT scans and of scintigrams were concordant in 103 patients (29 with embolism, 74 without). In 20 patients, intermediate-probability scintigrams were interpreted (six with embolism at angiography, 14 without); diagnosis with spiral CT was correct in 16. Interpretations of spiral CT scans and those of scintigrams were discordant in 12 cases; diagnosis with spiral CT was correct in 11 cases and that with scintigraphy was correct in one. Spiral CT and scintigraphic scans of four patients with embolism did not show embolism. Sensitivities, specificities, and kappa values with spiral CT and scintigraphy were 87%, 95%, and 0.85 and 65%, 94%, and 0.61, respectively. CONCLUSION: In cases of pulmonary embolism, sensitivity of spiral CT is greater than that of scintigraphy. Interobserver agreement is better with spiral CT.

Humans↗

PubMed1998

Intrapulmonary lesions: percutaneous automated biopsy with a detachable, 18-gauge, coaxial cutting needle.

PURPOSE: To evaluate a lung biopsy technique in which a detachable, 18-gauge, coaxial guide around a central notched stylet is used as a cutting needle. MATERIALS AND METHODS: The records of 89 consecutive patients (41 women, 48 men; aged 21-86 years) who underwent coaxial percutaneous core biopsy of 91 lung lesions that required needle passage through normal lung tissue (mean lesion size, 33.6 mm; range, 9-80 mm) were studied. Detachable, 18-gauge, coaxial automated cutting needles were used. RESULTS: The mean number of needle passes was 2.5 (range, 1-4). All biopsies yielded sufficient tissue for histopathologic (n = 91) and, if necessary, bacteriologic (n = 12) evaluation (mean core length, 5 mm; range, 1-15 mm). Eighty-nine lesions had definitive diagnoses. Seventy-five lesions were proved to be malignant; seventy (93%) could be accurately diagnosed with coaxial percutaneous core biopsy samples. Fourteen lesions were proved to be benign; 10 (71%) were specifically diagnosed with biopsy samples. Among the 91 biopsies, the overall diagnostic accuracy was 88% (80 of 91 lesions). A pneumothorax occurred in 31 cases (34%), three (3%) of which necessitated placement of a chest tube. Postbiopsy hemoptysis occurred and resolved spontaneously in nine cases (10%). CONCLUSION: This technique provides a core biopsy specimen without the need for an on-site cytopathologist during the procedure. It has a high diagnostic accuracy and an acceptable rate of complications.

Adult↗