Biomedical subjects
H Patriquin
Publications and source records attributed to H Patriquin.
Pneumatosis intestinalis and colocolic intussusception complicating Crohn's disease.
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Doppler US in patients with crohn disease: vessel density in the diseased bowel reflects disease activity.
PURPOSE: To determine if neovascularization associated with Crohn disease, as detected with Doppler ultrasonography (US), reflects clinical disease activity. MATERIALS AND METHODS: A devised measurement, vessel density, was estimated with color Doppler US. Patients with Crohn disease underwent clinical and laboratory assessment in which the Crohn disease activity index was measured; patients underwent abdominal US the same week. Color Doppler US was performed by using a 7.5-10.0- or 8.0-12.0-MHz transducer, the lowest possible pulse repetition frequency without aliasing, a low wall filter, and high Doppler gain settings. The length and thickness of the affected loops were measured, and the number of color Doppler signals per square centimeter in the bowel loop was counted. Pulsed Doppler US was used to confirm that the signals originated from arteries or veins and not from movement artifacts. RESULTS: Ninety-two patients (aged 7-20 years; mean, 14.85 years; 44 female, 48 male) underwent 119 examinations; 85 were performed in patients with active disease. Affected loops were thicker (10.6 vs 4. 6 mm; P: <.001) and had a higher vessel density with disease (69 of 119 examinations) than during remission (two of 34 examinations; P: <.001). CONCLUSION: Vessel density in affected bowel loops, as estimated with Doppler US, and bowel wall thickness (>5 mm) reflect disease activity in patients with Crohn disease.
Doppler sonography of head and neck masses in children.
This article presents a clinical approach to the investigation of a child with a mass of the head or neck. The anatomy of the head and neck region is reviewed, and the technique of Doppler sonography in children is outlined. The pathology and the sonographic appearance of common head and neck masses specific to children are described.
Liver disease in children with cystic fibrosis: US-biochemical comparison in 195 patients.
PURPOSE: To determine if abnormal liver architecture at ultrasonography (US) is related to abnormal function in children with cystic fibrosis (CF). MATERIALS AND METHODS: For 1 year, all 195 children (112 boys, 83 girls; mean age, 8.5 years) attending a CF clinic underwent abdominal US and a standard set of liver function tests. Aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyltransferase levels were analyzed. US signs were interpreted as follows: hypoechogenicity with prominent portal tracks as edema, hyperechogenicity as steatosis, and increased attenuation and nodules within or at the edge of the liver as cirrhosis. Signs of portal hypertension also were sought. US signs were compared with liver function test results. RESULTS: Liver sonograms were abnormal in 38 children (19%); of these, 24 (63%) had abnormal test results. The 157 children with normal liver architecture had a much lower prevalence of biochemical abnormality (33 patients [21%]; P < or = .001). All eight children with signs of portal hypertension had abnormal test results. Fourteen (82%) of 17 children with signs of cirrhosis had abnormal liver function. Eight (57%) of 14 patients with signs of steatosis had abnormal function. Diffuse hypoechogenicity of the liver with prominent portal tracks in 16 patients was associated with abnormal function in only five patients. CONCLUSION: The relation between abnormal liver architecture at US and results of three liver function tests in children with CF was significant. The most specific US abnormalities related to abnormal function are signs suggestive of portal hypertension and cirrhosis.
Soft-tissue venous malformations in pediatric and young adult patients: diagnosis with Doppler US.
PURPOSE: To describe the diagnostic features, appearance, and vascularization pattern of venous malformations (VMs) at Doppler ultrasonography (US). MATERIALS AND METHODS: Between February 1991 and May 1997, 51 soft-tissue VMs were studied with Doppler US in patients between 1 day and 21 years of age (mean age, 9 years). These VMs were located in the maxillofacial region (n = 19), trunk (n = 5), and upper (n = 10) and lower (n = 17) extremities. Twenty-three VMs had venographic confirmation, seven had only histologic confirmation, and 21 had both venographic and histologic confirmation. US was performed with 7.5- or 7-10-MHz linear transducers, a low pulse repetition frequency (mean, 1,680 Hz), and the lowest wall filter (25-50 Hz). RESULTS: At gray-scale US, VMs appeared as hypoechoic, heterogeneous lesions in 82% of cases. All lesions displayed compressibility. In eight lesions (16%), phleboliths were identified, thus confirming the diagnosis of VM. Analysis of vascular flow revealed monophasic, low-velocity flow in 40 VMs (78%), with an average flow velocity of 0.22 kHz. Biphasic flow was noted at the periphery of three lesions, which is indicative of a mixed capillary-venous malformation. The remaining eight lesions did not display any flow. CONCLUSION: In pediatric patients, Doppler US is a noninvasive, easily available, and rapid mode of investigation of vascular lesions and can help confirm the diagnosis of VM when it shows a characteristic flow pattern.
Doppler sonographic measurement of portal venous flow: what went wrong?
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Thickening of the wall of the bile duct due to intramural collaterals in three patients with portal vein thrombosis.
OBJECTIVE: We report three cases of a rare form of cavernoma developed within the wall of the common bile duct. CONCLUSION: To our knowledge, this kind of portal cavernoma has not been described in the literature. Because the cavernoma may be easily confused with other causes of bile duct wall thickening, color Doppler sonography is mandatory for a correct diagnosis.
[Role of transcranial ultrasonography in neuroradiological diagnosis].
Blood flow within the major arteries supplying the brain can be studied with transcranial Doppler sonography, a noninvasive, portable procedure. We describe the technique of examination, as well as indications in children and adults such as the investigation of intracranial stenosis, collateral pathways, vasospasm, cerebral emboli and arteriovenous malformations.
Power doppler sonography: basic principles and clinical applications in children.
Power Doppler sonography is a new technique that displays the strength of the Doppler signal in color, rather than the speed and direction information. It has three times the sensitivity of conventional color Doppler for detection of flow and is particularly useful for small vessels and those with low-velocity flow. Power Doppler sonography shows potential for detecting areas of ischemia in the kidney, brain, and prepubertal testis and for demonstrating hyperemia in areas of inflammation. Its increased sensitivity to motion and flash artifact, however, limits its application in children. Power Doppler is useful as an adjunct to conventional color and pulsed Doppler sonography.
Imaging features of type 1 hereditary tyrosinemia: a review of 30 patients.
Hereditary tyrosinemia type 1, a common genetic disorder in the province of Quebec, is characterized by a deficiency of fumarylacetoacetate hydrolase. In this autosomal recessive disorder of tyrosine metabolism, the accumulation of succinylacetone leads to neurologic crises, acute and chronic liver failure, complex renal tubulopathy, rickets and a hemorrhagic syndrome. Liver trans- plantation has dramatically modified the spontaneous course of this lethal disease. The present paper describes the imaging features of tyrosinemia in 30 patients followed from 1980 to 1995 at Hôpital Sainte-Justine, Montreal, Canada.
Intrarenal arterial Doppler sonography in the detection of renal vein thrombosis of the native kidney.
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Short- and long-term hemodynamic effects of transjugular intrahepatic portosystemic shunts: a Doppler/manometric correlative study.
OBJECTIVE: The purposes of this study were to evaluate the effect of a well-functioning transjugular intrahepatic portosystemic shunt (TIPS) on the splanchnic and intrahepatic circulation, to determine if sonographic measurements can predict shunt dysfunction before clinical manifestations of portal hypertension occur, and to compare Doppler sonographic findings with portocaval gradient measurements before and after shunt revision. SUBJECTS AND METHODS: Forty-four patients with cirrhosis (n = 43) and myelofibrosis (n = 1) who underwent successful TIPS insertion were included in this prospective study. Indications for TIPS placement were: refractory ascites (24 patients), bleeding esophageal varices (17 patients), portal hypertensive gastropathy (two patients), and bleeding colonic varices (one patient). The portal vein and the inferior vena cava were catheterized; and the portocaval gradient was recorded before TIPS placement, at 2 and 12 months after TIPS placement, and when clinical or Doppler findings suggested shunt dysfunction. Doppler studies were done within 1 week before TIPS placement, within 2 days after TIPS placement, every 2-3 months thereafter, and before and after a TIPS revision. The Doppler studies included flow volume measurements in the portal vein and in the stent, as well as determination of the direction of flow in the segmental branches of the portal vein, in the splanchnic veins, and in portosystemic collaterals. Changes in Doppler findings and in catheter pressure measurements were compared using Spearman's rank correlation test. Significance was set at the .05 level. RESULTS: A marked decrease (-51%) in portocaval gradient was observed after TIPS placement. At Doppler sonography, portal vein velocity and diameter were both higher after TIPS placement, resulting in a marked increase in portal venous flow (170%). Mean flow velocity in the shunt was 55.8 +/- 3.6 cm/sec, and flow volumes in the shunt and in the main portal vein were 1596 ml/min and 1731 ml/min, respectively (p = nonsignificant). Dysfunction of the stent occurred in 27% of the patients. Changes in stent blood flow volume were closely related to changes in the portocaval gradient (r = -0.67, p < .001). Reduction of blood flow volume in the stent or change of direction of flow in intrahepatic portal veins or in collateral veins signaled shunt dysfunction (84% sensitivity, 89% specificity). CONCLUSION: Marked hemodynamic changes in the portal venous system occur soon after a TIPS procedure. Monitoring of shunt function with periodic Doppler sonography, including calculation of shunt blood flow, is useful in detecting shunt dysfunction before clinical signs occur.
Cavernous transformation of the portal vein: patterns of intrahepatic and splanchnic collateral circulation detected with Doppler sonography.
OBJECTIVE: Cavernous transformation of the portal vein is defined as the formation of venous channels within or around a previously thrombosed portal vein. The purpose of this work was to study the hemodynamic consequences of cavernous transformation of the portal vein in a group of afflicted patients by use of Doppler sonography. We wished to study the evolution from portal vein thrombosis to the formation of cavernous transformation, the extent of resulting extrahepatic collateral channels, and the patterns of splanchnic collateral circulation. MATERIALS AND METHODS: Seventy-five patients (48 adults and 27 children) with cavernous transformation of the portal vein were studied with color and/or pulsed Doppler sonography. Blood flow in the extrahepatic portal vein, in its segmental branches, in the hepatic veins and artery, and in the splanchnic veins was examined. Collateral pathways were sought. For nine patients with acute thrombosis of the portal vein, serial examinations were performed during the formation of cavernous transformation. RESULTS: In nine patients, a fresh thrombus filled and distended the portal vein and became recanalized within a few days. Tortuous vessels appeared at the porta hepatis. These were characterized as veins or arteries with Doppler sonography. Soon the portal vein could no longer be identified within the mass of tortuous vessels. The cavernous transformation developed within 6-20 days of the acute thrombosis. A spongelike mass of collateral vessels around the main portal vein was seen in all but two patients. Intrahepatic extension of the cavernous transformation was seen in 57 patients (76%) and involved one or more intrahepatic portal veins. Two types of collateral circulation were observed: portosystemic, mainly through the left gastric and the perisplenic veins (the caput medusae, i.e., the paraumbilical-to-abdominal venous route, was never seen); and portoportal, from the periportal or pericholecystic venous channels to the intrahepatic portal veins. In nine patients, flow within unaffected intrahepatic branches of the portal vein was reversed as directed toward the cavernous transformation surrounding other, thrombosed intrahepatic segments of the portal vein. CONCLUSION: After thrombosis of the portal vein, portoportal venous channels may form not only at the porta hepatis but also within the liver. Intrahepatic blood may be shunted from one segmental portal vein to another. In addition, portosystemic collateral channels are formed, suggesting that, despite extensive hemodynamic adaptations, portal hypertension ensues.
Meal induced changes in hepatic and splanchnic circulation: a noninvasive Doppler study in normal humans.
The haemodynamic effects of a meal on the splanchnic and hepatic circulation were evaluated in 30 healthy volunteers, using Doppler ultrasonography. The resistance index (RI) of the superior mesenteric artery and of the left and right intrahepatic arteries, the portal vein blood flow as well as the ratio between maximal velocity in the left and right intrahepatic arteries and the adjacent portal vein were measured initially, then 15, 30, 45, and 60 min after the ingestion of a standard balanced liquid meal. Postprandial haemodynamic changes were maximal 30 min after the meal; at that time, mesenteric artery RI decreased significantly [mean -11% (SEM 14%)] whereas portal vein blood flow increased markedly [mean +79% (SEM 14%)]; a significant increase in hepatic artery RI was observed in both liver lobes. The ratio between maximal velocities of the intrahepatic artery and the intrahepatic portal vein was reduced significantly; this ratio decreased more markedly in the right lobe of the liver. These findings would suggest that there was an adaptation of hepatic artery to portal vein blood flow after a meal. The subsequent increase in intrahepatic portal vein flow velocity was found to be greater in the right lobe of the liver.
Duplex Doppler sonographic examinations of the testis in prepubertal boys.
This retrospective study of 143 pediatric patients with unilateral acute scrotal disease was done to assess the value of duplex Doppler sonographic examination prior to puberty (110 patients) in comparison to a pubertal group (33 patients) in a pediatric hospital, where the examinations are done by staff radiologists and radiology residents of varying degrees of expertise and experience with Doppler technique. All patients seen during an 18 month period were included. The unaffected side was examined in most patients and served as control. The normal Doppler shift in the center of the prepubertal testis was found to be 0.2 to 0.5 kHz, when using a 5 MHz duplex Doppler probe. With puberty, the Doppler shift increased to 0.5 to 1 kHz. Of 18 patients (10 prepubertal) with testicular torsion, five (three prepubertal) had false-positive Doppler shift. In four of these five cases, faulty placement of the Doppler sample volume cursor was probably the cause. Using a multi-way frequency analysis, puberty was found to have no significant influence on results of Doppler signal (chi square = 0.1346; P = 0.7137). Duplex Doppler sonographic examination is as useful to rule out testicular torsion in prepubertal boys as it is after puberty. Meticulous technique is essential. The opposite side should be examined first and serves as control for the affected one. Results showing no flow in the center of the diseased testis with positive flow in the unaffected one should lead to further clinical action (scintigraphy or surgery).
Malignant microvasculature in abdominal tumors in children: detection with Doppler US.
Malignant tumors produce a network of microscopic, thin-walled vessels that invade the host and provide the blood supply essential for growth. This network, situated at the periphery of malignant tumors, gives rise to characteristic, high-velocity Doppler shifts at ultrasound (US) scanning and was sought in 54 children with abdominal masses. Characteristic high-frequency Doppler signals (greater than 2.5 kHz) were found in 27 of 35 malignant tumors. These signals disappeared during successful chemotherapy in three children with neuroblastoma in whom the signals had been documented initially. The signals were absent in three other children, who had undergone clinically successful therapy, and were present in two children with rapidly progressing tumors despite chemotherapy. In 14 children, none of the benign tumors showed high-frequency Doppler shifts. The search for malignant neovasculature with Doppler US scanning may provide insight into tumor behavior. The Doppler US examination, a noninvasive adjunct to routine US, may become useful at both the time of diagnosis of a mass and afterward to assess the effect of chemotherapy.
Renal arterial stenosis: slowed systole in the downstream circulation--experimental study in dogs.
To test the effect of stenosis of the renal artery on the downstream intrarenal blood flow, a snare was placed around the renal artery in 10 dogs and compressed to create stenosis while Doppler curves were obtained from interlobar arteries. Pulsed Doppler examination of the segmental and interlobar arteries was performed by means of placement of a 7.5-MHz mechanical sector transducer directly on the surface of the kidney. The following calculations were made: degree of stenosis (evaluated with aortography), acceleration index (AI) (the acceleration of systole), and resistive index. The Doppler measurements were compared with findings on angiograms. The AI for normal arteries ranged from 2.2 to 4.3, and for arteries with 75% or greater stenosis, from 1.0 to 1.3. Systolic peaks disappeared as near occlusion was achieved. These changes were reversible within seconds of release of the arterial snare. Such change is identical to change in the pulsus tardus and parvus waveforms seen in both acute and chronic severe stenosis of the renal artery in humans.