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Biomedical subjects

M Lafortune

Publications and source records attributed to M Lafortune.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Transcranial Doppler ultrasound].

Over the last decade, transcranial Doppler examination of the cerebral vessels has been made possible by the development of a high-intensity, low-frequency (2 MHz) pulse probe. The middle, the anterior and the posterior cerebral arteries, the cavernous portion of the carotid artery and the basilar artery can thus be easily studied transtemporally or transorbitally or from below the foramen magnum. The transcranial Doppler examination is already used clinically to study arteriosclerosis and in the diagnosis and follow-up of vasospasm and arteriovenous malformations. This review describes the examination procedure and summarizes and illustrates its major indications.

Basilar Artery↗
PubMed1990

Ureterovesical jets in infants and children: duplex and color Doppler US studies.

Ureteric jets were studied with conventional duplex Doppler (79 patients) and with color Doppler flow imaging (22 patients). Correlation with voiding cystourethrography (VCUG), performed ont he same day, was obtained in all patients. Thirty-six patients with normal VCUG results and normal renal and bladder ultrasound (US) studies served as the control group for 39 patients with vesicoureteric reflux (VUR) and 26 patients with urinary tract disorders other than reflux. The site of the ureteric orifice and duration, direction, and turbulence of the jets were recorded. Duration varied from 0.4 sec to 7.5 sec and depended largely on fluid intake. Duration varied in an individual patient by up to 2 sec from one jet to another. The direction of the normal jet was anteromedial and upward. Jets from refluxing ureters can appear normal. Severe renal parenchymal scarring reduced frequency and amplitude of the jets. Doppler analysis of the ureteric jet does not allow diagnosis or exclusion of VUR. Color Doppler was more sensitive in demonstrating ureteric jets than was gray-scale, real-time US and facilitated the study, but it was equally unable to help predict reflux.

Adolescent↗
PubMed1990

Fetal lobation. An anatomo-ultrasonographic correlation.

Remnants of the fusion of fetal renunculi have been mistaken for renal scars or tumors. We compared anatomic cuts of 24 cadaveric kidneys with fetal lobation (ages ranged from 16 weeks gestation to 49 years) to identical ultrasonographic sections performed in a water bath and to sonograms of healthy persons of similar ages as the cadavers. Fetal lobation was characterized as follows: there were fine, linear demarcations indenting the renal surface, separating normal lobes, consisting of a central pyramid and surrounding cortex. Separate renunculi seen in early fetal life progressively fuse throughout gestation, leaving interlobar grooves. During the third trimester, the renal surface becomes smoother and the interlobar grooves become invisible. One prominent indentation of the renal surface, the interrenuncular junction, incorporates perirenal fat and invaginates the anterior surface of the upper third of the kidney to the hilum and is the most easily visible remnant of fetal lobation. The sharply defined linear remnants of interlobar grooves should not be mistaken for scars, which are wider, less well defined and always associated with loss of renal cortex.

Adolescent↗
PubMed1989

[Doppler ultrasound and portal hypertension: quantitative analysis].

Usually, the clinical evaluation of diffuse hepatic changes only needs the answers to three important questions: is there a flow, in which direction and are the porto-caval shunts efficient? When an answer is found to these questions, the quantitative measurement of the portal flow can give complementary precisions to achieve a better physiopathological understanding of portal hypertension or blood malignancies and for the follow-up evaluation.

Adult↗
PubMed1989

[Doppler ultrasound in portal hypertension: qualitative analysis].

Duplex Doppler US is a procedure that enables confirmation--and in many instances--detection of portal hypertension by visualizing the presence of collateral blood vessels and determining the direction of the portal flow. In addition, absence of Doppler signal into the veins allows assessment of venous thrombosis both in the portal and hepatic veins.

Budd-Chiari Syndrome↗
PubMed1988

The radiological report: what is useful for the referring physician?

To assess what constitutes a useful radiological report for referring physicians, we sent a questionnaire to 200 doctors (general practitioners, internists, and surgeons). Questions testing style, length of the report, and several points of content, including mention of clinical correlation, negative findings, and sequence of further investigations, were included. The principal qualities useful to the clinician were clarity, brevity, and clinical correlation. Advice on planning of future investigations was especially valued by general practitioners.

Communication↗
PubMed1987

Non-surgical treatment of a congenital splenic cyst.

A congenital splenic cysts in a 5.5 year old girl was aspirated under ultrasonographic guidance and injected with 150 mg Tetracycline (intended for IV use). Septation and gradual resorption of the cyst occurred during the following weeks, leaving small residual cysts which have remained stable for the last 12 months. Splenectomy and its possible complications were avoided.

Child, Preschool↗
PubMed1987

Surgical portosystemic shunts in children: assessment with duplex Doppler US. Work in progress.

The patency of 12 surgical portosystemic shunts in 11 children with portal hypertension was assessed with duplex Doppler ultrasonography. Results were compared with surgical, angiographic, and clinical findings. Seven of nine patent shunts were directly seen, and flow in them was assessed. One proximal splenorenal and one mesentericocaval shunt were not directly seen because of intestinal meteorism. The obstructed shunts were not seen, and no flow could be detected at their site. The presence and direction of flow in the splanchnic venous system were determined in all children, obviating the need for further angiographic studies.

Adolescent↗
PubMed1987

Duplex Doppler examination in portal hypertension: technique and anatomy.

Three hundred fifty duplex Doppler examinations were performed in 195 patients (150 adults and 45 children) with radiologically and/or clinically proved portal hypertension. In this paper we describe this duplex Doppler technique for the qualitative assessment of splanchnic venous hemodynamics in these patients. The caliber of and the presence and direction of flow in the following veins are assessed: splenic, superior mesenteric, portal and intrahepatic portal, and portasystemic collateral. This examination can be performed on patients of any age without sedation and can establish the diagnosis of clinically significant portal hypertension. Technical success rate was 95%, although 10% of examinations were incomplete because of intestinal meteorism. We conclude that the combined use of Doppler and routine sonography permits precise evaluation of the vascular anatomy in portal venous hypertension.

Adolescent↗
PubMed1987

Hemodynamic changes in portal circulation after portosystemic shunts: use of duplex sonography in 43 patients.

Forty-five patients with 46 surgical portosystemic shunts were examined by duplex Doppler sonography, and the results were compared with those of esophageal endoscopy, angiography, surgery, and clinical follow-up. Thirty-eight shunts were patent, and in 33 of these, the shunt was directly visualized and flow was observed with Doppler sonography. Eight shunts were obstructed. After a successful portosystemic shunt procedure, flow in the shunted splanchnic vein was directed toward the shunt and the systemic vein. We studied the intrahepatic portal venous circulation in all of the patients; we found that in the presence of patent portosystemic shunt, portal flow is hepatofugal. This reversal of blood flow occurred in all but four patients. In the end-to-side portacaval shunt, where the portal vein is ligated, blood in intrahepatic portal branches presumably reaches the shunt through perihepatic collaterals. In the presence of a thrombosed shunt, intrahepatic portal venous flow was hepatopetal. To our knowledge, this is the first noninvasive in vivo study of intrahepatic portal circulation after portosystemic shunt surgery. The duplex Doppler evaluation of portosystemic shunts appears to be reliable and should be the method of choice for shunt patency assessment in patients with recurrent signs of portal hypertension. In addition to demonstrating flow at the site of the anastomosis, the Doppler study may yield an easy and reliable sign of shunt patency: reversed flow (hepatofugal flow) in the intrahepatic portal veins probably signals a patent shunt, even if the site of the anastomosis cannot be visualized directly by sonography.

Adolescent↗
PubMed1986

Ascites: ultrasound guidance or blind paracentesis?

The classic site for paracentesis in generalized ascites is in the left lower quadrant of the abdomen at a position equivalent to McBurney's point. Its use has an average success rate of 58%, depending on the amount of liquid. To assess the efficacy of paracentesis at this site and to establish the ideal site for blind puncture, we studied 27 consecutive patients with ascites detected by abdominal ultrasonography. The amount of ascites was graded from 1 to 4. Free fluid had accumulated mostly in the perihepatic region, then around the bladder and in the right paracolic gutter, and finally in the left flank. In six of the eight patients in whom fluid was found in the left or right flank, air-filled bowel loops were observed between the abdominal wall and the fluid, in the expected path of a blind puncture. These findings suggest that the safety and efficacy of paracentesis would be greatly improved by ultrasonographic guidance.

Adult↗
PubMed1986

Sonography of the hypertrophied column of Bertin.

A prospective sonographic analysis of kidneys in 136 adults without clinical or radiologic evidence of renal disease revealed 22 cases of large columns of Bertin. Most were located in the middle third of the kidney, more frequently on the left side. They were bilateral in 18%. Water bath sonograms of normal cadaver kidneys and subsequent anatomic correlation revealed hypertrophied columns and confirmed the sonographic findings seen in vivo. The following are characteristic of a hypertrophied column of Bertin: It is a projection of cortex into the renal sinus (and therefore is isoechogenic with it). The sinus may engulf it in a clawlike fashion. The renal contour is smooth. Sonography is characteristic and obviates further investigation.

Adolescent↗
PubMed1986

The V-shaped artifact of the gallbladder wall.

Among 20,000 patients who had undergone abdominal or gallbladder sonographic examinations, 36 had a short V-shaped artifact originating from an hyperechoic focus in the gallbladder wall. Associated symptoms were varied and nonspecific. The 10 gallbladders excised because of associated cholelithiasis showed a thickened wall, and seven patients had diverticulosis of the wall with impacted stones. In vitro sonographic examination of five gallbladders reproduced the "V" artifact and showed that it originated from a small intramural cholesterol stone. The V artifact should be distinguished from the larger comet-tail and ring-down artifacts, which arise from metal or gas.

Adult↗