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Biomedical subjects

M Rioux

Publications and source records attributed to M Rioux.

At least 19 recordsLinked to original sources
PubMed2006

Ferrofluidic adaptive mirrors.

A magnetic liquid mirror based on ferrofluids was demonstrated. Magnetic liquid mirrors represent a major departure from solid mirror technology. They present both advantages and disadvantages with respect to established technologies. Stroke (from a fraction of a wave to several hundreds of micrometers), cost (a few dollars per actuator), and scalability (hundreds of thousands of actuators) are the main advantages. Very large mirrors having diameters of the order of a meter should be feasible. There are a few disadvantages. The most important disadvantage is the time response, which is of the order of a few milliseconds. Although this time response could be further decreased with additional technical developments, it is unlikely to match the speed of solid mirrors. The technology is still in its infancy, and considerable work must still be done. However, the advantages are such that the technology is worth pursuing.

Journal Article↗
PubMed2001

Efficacy of a clinical medication review on the number of potentially inappropriate prescriptions prescribed for community-dwelling elderly people.

BACKGROUND: The administration of many drugs concurrently to elderly patients is a well-known problem in geriatrics and involves numerous risks. One way to reduce polypharmacy is to provide information to physicians in order to modify their prescribing practices. The main objective of this study was to evaluate the impact of an intervention program that targeted physicians with the aim of reducing the number of potentially inappropriate prescriptions (PIPs) given to elderly patients. METHODS: A randomized controlled trial was carried out among community-dwelling elderly people in Sherbrooke, Que. The participants were 266 patients over 75 years of age (experimental group: n = 136, control group: n = 130). A team comprising 2 physicians, a pharmacist and a nurse reviewed the list of drugs and the diagnoses of a subgroup of the experimental group in a case conference. Suggestions were formulated and mailed to the patients' physicians together with relevant scientific documentation justifying the recommendations. The main outcome measure was the number of PIPs. RESULTS: The mean number of PIPs per patient declined by 0.24 in the experimental group (n = 127) and by 0.15 in the control group (n = 116). The decline in PIPs was even larger in the experimental group that had case conferences (n = 80), in which the mean number of PIPs per patient declined by 0.31. However, this difference between the experimental group and the control group was not statistically significant in the intent-to-treat analysis. The number of drugs prescribed was not modified by the intervention, nor were the results of the global assessment of the patients' drug profiles. INTERPRETATION: This study suggests that the intervention program had no effect on the prescribing of PIPs.

Activities of Daily Living↗
PubMed2001

Ultrasonography of chronic inflammatory bowel diseases.

Advances in the understanding of bowel appearances with high-resolution sonography have led to consideration of this technique as an important tool for bowel disease assessment. Ultrasonography may display the transformation of the intestinal wall from normal to pathological state in inflammatory diseases. Furthermore, intestinal ultrasonography may serve as a diagnostic clue if typical patterns of the bowel wall are demonstrated. Thus, Crohn's disease, ulcerative colitis, diverticulitis, or infectious ileocolitis may be specifically demonstrated in the majority of cases. Besides showing the parietal signs of inflammation, ultrasonography also shows the perigut abnormalities and may demonstrate complications such as fistulas and abscesses. Finally, with the help of Doppler, some additional information may be obtained about the activity of chronic inflammatory diseases. In clinical practice, used in combination with other imaging modalities, such as CT or endoscopy, bowel ultrasonography appears to be a non-invasive and effective diagnostic tool for the diagnosis and follow-up of Crohn's disease and ulcerative colitis.

Colitis, Ulcerative↗
PubMed1998

[The contribution of ultrasonography to various pathologies of the small intestine].

Ultrasonography has progressively become an easily available non expensive imaging modality for the study of the small intestine. It has no secondary effects and is comforting for the abdominal radiologist. Further, as ultrasonography does not require special preparation nor contrast administration in the intestine or vascular system, no delay is caused if other imaging modalities (such as CT or angiography) have to be performed. This report covers the most common pathologic conditions in the small bowel and does not consider enteroliths, foreign bodies nor mucoviscidosis.

Celiac Disease↗
PubMed1995

Cystic lymphangioma of the colon: ultrasonographic and computed tomographic features.

Cystic lymphangioma is a rare benign tumour of the gastrointestinal tract. The authors describe a 52-year-old woman with cystic lymphangioma in the ascending colon. Ultrasonographically, the lesion was compressible and anechoic and showed posterior acoustic enhancement. Doppler analysis showed no flow within the lesion. On computed tomography the lesion appeared as a focal thickening of the colonic wall with attenuation values of 6 to 10 Hounsfield units. The lesion extended along the wall and did not invade the adjacent fat. It could not be located during endoscopy or laparotomy and was eventually located for resection with intraoperative ultrasonography.

Colonic Neoplasms↗
PubMed1994

Sonographic detection of clinically unsuspected swallowed toothpicks and their gastrointestinal complications.

We retrospectively analyzed the clinical presentation and imaging investigation in 4 cases of surgically (2 cases) or endoscopically (2 cases) proven toothpick-related gastrointestinal perforation. The toothpick perforated the stomach (2 cases), the sigmoid (1 case), and the ileum (1 case). Sonographic appearance of the toothpick was a linear, hyperechoic (3 cases) or hypoechoic (1 case) image of variable length (mean: 2.5 cm) with inconsistent posterior shadowing in the longitudinal axis. In transverse section a hyperechoic dot (4 cases) with clear, thin, sharp, posterior shadowing (3 cases) was seen. Following sonography (4 cases), CT scan (2 cases), and upper GI study (2 cases), the preoperative diagnosis of GI perforation by foreign body compatible with toothpick was made in all cases, although none of the patients was aware of having swallowed a toothpick. This information will be of help in making early sonographic diagnosis of toothpick-related GI perforation in patients with or without symptoms.

Adult↗
PubMed1994

A randomized, double-blind, placebo-controlled study on the effect of conjugated estrogens on skin thickness.

OBJECTIVE: Our purpose was to assess the potential benefit of therapy with conjugated estrogens therapy on skin thickness in postmenopausal women. STUDY DESIGN: Sixty postmenopausal women were randomly allocated to receive conjugated estrogens or placebo treatment for 12 months. Neither participants nor investigators were aware of the group allocation. Skin thickness was measured by ultrasonography at baseline and after 6 to 12 months of treatment. Histologic changes were evaluated by skin biopsy at baseline and after 12 months' treatment. Quality of life and adverse events were recorded at each visit and at the end of treatment. RESULTS: Treatment with conjugated estrogens for 12 months significantly increases, at the level of the right great trochanter, the thickness of the skin (p < 0.01), as assessed by ultrasonography, and of the dermis (p < 0.05), as assessed by skin biopsy. No statistically significant difference was observed in the control population. Quality of life was reported to be improved (p < 0.05) in women treated with estrogen compared with those in the placebo group. CONCLUSION: The results may help postmenopausal women to better appraise the benefits of estrogen replacement therapy, and they provide further evidence of the potential of conjugated estrogens in preventing skin aging.

Aged↗
PubMed1994

Primary epiploic appendagitis: clinical, US, and CT findings in 14 cases.

PURPOSE: To describe the appearance at ultrasonography (US) of primary epiploic appendagitis in correlation with computed tomographic (CT) findings. MATERIALS AND METHODS: From January 1992 through June 1993, clinical, US, and CT findings were reviewed in 14 patients with primary epiploic appendagitis (seven men and seven women, aged 25-51 years [mean, 39 years 3 months]). Follow-up examinations were performed with US alone (n = 4), with US and CT (n = 3), and with clinical examination (n = 14). Surgery was performed in two patients. The main symptoms were right (n = 3) or left (n = 11) flank pain. RESULTS: US revealed an echogenic mass that was small, ovoid, and noncompressible, located anterolateral to the right colon (n = 3), anterior or anterolateral to the left colon (n = 10), and anteromedial to the left colon (n = 1). CT helped confirm the presence of a fatty lesion in each patient without other inflammatory process in the abdomen. Symptoms resolved within 7 days in 12 patients. CONCLUSION: Primary epiploic appendagitis has fairly characteristic US and CT features that enable a rapid diagnosis.

Abdomen, Acute↗
PubMed1994

Colonic bull's-eye lesions in histiocytosis X.

A 27-year-old woman with known pulmonary, cutaneous and osseous histiocytosis X presented with vague abdominal pain. Double-contrast barium enema examination revealed multiple colonic bull's-eye lesions. Biopsy showed histiocytic infiltration similar to that already described at other sites in this patient (the lungs and bone). To the authors' knowledge, this case represents the first radiologic description of this manifestation of histiocytosis X. Though rare, it should be considered in the differential diagnosis of colonic bull's-eye lesions.

Adult↗
PubMed1993

Thoracic splenosis after blunt trauma: frequency and imaging findings.

OBJECTIVE: Thoracic splenosis is an uncommon sequela of simultaneous splenic and diaphragmatic injury. The aim of this prospective study was to evaluate the prevalence of thoracic splenosis in 17 subjects who had sustained splenic and diaphragmatic injury and to describe the CT and MR features of thoracic splenosis. SUBJECTS AND METHODS: All patients had 99mTc-RBC scintigraphy. Subjects with radionuclide uptake in the thorax were further examined with radiography, CT, and MR imaging of the chest. RESULTS: Three subjects (18%) had evidence of ectopic splenic activity in the left side of the thorax. The CT features consisted of one pleural nodule and two pleural masses. The MR appearance of the ectopic splenic tissue was similar to that of normal spleen. CONCLUSION: Thoracic splenosis occurs with moderate frequency after combined splenic and diaphragmatic injury. The CT appearance is that of pleural masses or nodules. The MR appearance is relatively similar to that of normal spleen.

Adult↗
PubMed1993

Primary pulmonary hypertension associated with HIV infection.

A Haitian woman with the human immunodeficiency virus (HIV) presented with dyspnea, cough, fatigue and lower abdominal pain of recent onset. Clinical, radiologic and hemodynamic investigations demonstrated pulmonary hypertension. The patient died a few days later. The pathological findings were compatible with primary pulmonary hypertension. This case is similar to others that have been reported and indicates a possible link between HIV infection and rapidly progressive primary pulmonary hypertension.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Ultrasonographic features of abdominal ectopic splenic tissue.

Ectopic splenic tissue may be congenital (an accessory spleen) or a result of traumatic autotransplantation (splenosis). The purpose of this study was to identify the features of ectopic splenic tissue in ultrasonography (US) scans. Selective spleen scintigraphy (with heat-denatured erythrocytes labelled with technetium 99m) was performed on 33 patients who had undergone splenectomy after trauma; the 25 (76%) for whom the results were positive subsequently underwent US. Of the 25 patients, 23 (92%) had one to five foci of ectopic splenic tissue; 62 of the 68 foci (91%) were in the left upper quadrant. US identified splenic tissue in 17 of the 25 patients (68%). All 44 foci visible with US were hypoechoic, and 33 of them (75%) exhibited acoustic enhancement or an incomplete hyperechoic rim or both. Nineteen of the foci revealed by US (43%) were smaller than 1 cm2. No criteria were found to permit differentiation of accessory spleens from splenosis. In three of every four patients who undergo splenectomy after trauma, ectopic splenic tissue eventually develops. Radiologists should be aware of this condition to avoid incorrectly diagnosing this ectopic tissue as metastasis, adenopathy or another solid tumour. US, in combination with selective spleen scintigraphy, permits a specific diagnosis without invasive procedures.

Abdominal Neoplasms↗
PubMed1992

Sonographic detection of the normal and abnormal appendix.

A prospective study of 170 patients with suspected appendicitis was performed to assess the value of sonography in detecting the normal and abnormal appendix. The wall thickness (normal, less than or equal to 3 mm), compressibility of the appendix, and echogenicity of surrounding fat were the primary criteria used to determine the status of the appendix. Of 60 patients who underwent surgery, appendicitis was proved in 45. The remaining 110 patients who did not have surgery, contacted by telephone at the end of the study, had no clinical follow-up evidence of acute appendicitis. A normal appendix was clearly identified in 102 (82%) of 125 patients without acute appendicitis. The sensitivity of sonographic examination in detecting appendicitis was 93%, the specificity was 94%, and the accuracy was 94%. The predictive value of a positive test was 86%; that of a negative test was 98%. Ruptured appendicitis was predicted in all cases (11/11). Sonography is useful in detecting acute appendicitis and can clearly show the normal appendix more frequently than previously reported.

Acute Disease↗
PubMed1992

Ultrasonographic appearance of appendiceal endometrioma.

Endometriosis may involve the gastrointestinal tract, but only rarely is the appendix affected. The authors report the ultrasonographic appearance of appendicular endometriosis, which was unexpectedly discovered in a 31-year-old woman. The lesion was also demonstrated by computed tomography and an upper gastrointestinal tract radiographic series after barium ingestion. The diagnosis was confirmed by surgery. The authors believe this to be the first description of the ultrasonographic appearance of appendicular endometriosis.

Adult↗
PubMedDate not supplied

Sonographic appearance of primary small bowel carcinoid tumor.

BACKGROUND: To assess the value of sonography in the diagnostic work-up of small bowel carcinoid tumors and characterize their sonographic appearance. METHODS: We retrospectively reviewed the sonographic findings (size, shape, echogenicity, contour, location, wall thickening, serosal transgression, vascularity) of all cases of carcinoid tumors investigated between January 1988 and January 1993. Six tumors, in five patients with histologic proof, were analyzed and, when possible, correlation with pathological or surgical results was made. RESULTS: In four out of five cases, the tumor was not suspected clinically prior to sonography; in one case, a small synchronous lesion was only found at surgery. Its sonographic appearance was a hypoechoic, homogenous, predominantly intraluminal mass with smooth intraluminal contour and attached to the wall by a broad base with interruption of the submucosa and thickening of the muscularis propria in all cases. There were signs of serosal transgression in four cases, puckering and retraction in two cases, hypervascularity in two cases, and mesenteric involvement in three cases. All lesions were located in the ileum and the mean diameter was 22 x 17 mm. CONCLUSION: Ultrasonography was useful in the detection of primary carcinoid tumors of small bowel. Their sonographic characteristics were described and some of them were highly suggestive of the diagnosis.

Carcinoid Tumor↗
PubMedDate not supplied

Sonographic detection of peritoneal carcinomatosis: a prospective study of 37 cases.

BACKGROUND: The use of sonography as an accurate modality to detect peritoneal carcinomatosis in patients with or without known malignancy was investigated. METHODS: Using ultrasound, we prospectively diagnosed peritoneal carcinomatosis in 37 patients. Findings such as liver metastases, adenomegalies, ascites and gallbladder wall thickness were first assessed. Then high resolution sonography detected omental, mesenteric, serosal and peritoneal involvement, the latter presenting as a nodule or an interruption of the anterior hyperechoic peritoneal line. Percutaneous biopsy under sonographic guidance of detected lesions, surgery or autopsy confirmed the peritoneal carcinomatosis. Sonographic search for the primary neoplasm was simultaneously done. RESULTS: Carcinomatosis was proven in all 37 cases. Omental involvement was found in 36 cases (97%), serosal implants in 7 cases (19%), mesenteric involvement in 6 cases (16%), peritoneal implants in 20 cases (54%). Interruption of the anterior peritoneal line was found in 6 cases (16%), liver metastasis in 14 cases (38%), lymphadenopathies in 9 cases (24%), and significant ascites in 18 cases (49%). Gallbladder wall thickness was not a useful criterion since 12 patients (32%) had previous cholecystectomy. Biopsy of detected lesions was performed in 21 cases with 100% positive results for malignant cells. Sonography detected the primary tumor in 16 (57%) out of 28 patients without known malignancy. CONCLUSION: Sonography was very useful for prospective detection of peritoneal carcinomatosis and the omental abnormality was the single most useful sign. Furthermore, sonographic findings, confirmed by percutaneous biopsy, prevented 24 unnecessary exploratory laparotomies.

Adult↗