Biomedical subjects

Olivier Lucidarme

Publications and source records attributed to Olivier Lucidarme.

10 recordsLinked to original sources

PubMed2006

Fusion of the midplane with the left intersectional plane: a liver anatomical variation revisited with multidetector-row CT.

This article updates the description of an anatomical variation of the liver, in which the gallbladder is adjacent to the ligamentum teres, that was described until now as "right-sided ligamentum teres and right umbilical portion of the portal vein". A study of eight patients showing this anatomical variation has led to a new archetypal anatomical description of the hepatic and portal veins, using multidetector-row computed tomography (MDCT) with three-dimensional (3D) volume-rendering (VR) reconstructions. While 2D axial imaging gave the same information, MDCT imaging with VR reconstructions provided a clear 3D visualization of this anatomical variation. Typical features can be described as follows: (1) juxtaposition of the ligamentum teres and the gallbladder; (2) typical portal vein branching with a right posterior branch, a left posterior branch and a main medial branch that terminates in the ligamentum teres; (3) two main hepatic veins and a hypotrophied medial hepatic vein. We think, based on the direct comparison of anatomical findings and knowledge of chronological embryological development, that this abnormality results from the defective development of the central part of the liver and not from the persistence of the right rather than the left umbilical vein. Because of the presence of only one medial plane, containing both the gallbladder and the ligamentum teres, we propose renaming it "fusion of hepatic planes".

Adult↗

PubMed2006

Angiogenesis: noninvasive quantitative assessment with contrast-enhanced functional US in murine model.

PURPOSE: To evaluate quantitative functional ultrasonography (US) in a murine gel model by using microbubble destruction kinetics to determine whether parametric indices provided with US could help assess angiogenesis. MATERIALS AND METHODS: Institutional Animal Subjects Committee approved experiments and procedures. In 36 normal mice, two 0.4-mL gel implants were placed subcutaneously on either side of spine. One implant contained 0.5, 1.0, or 1.5 microg human basic fibroblast growth factor (bFGF) per milliliter of gel. Functional US quantitative analysis of angiogenesis with microbubble contrast agent was performed on days 3, 6, 9, and 12; histologic data were collected. Time-intensity curve of implant was fitted to mathematic decay model to calculate fractional blood volume and fraction of blood replaced per unit of time. Microvascular density (MVD) and percentage of microvascular area (MVA) were measured after anti-CD31 staining. Spearman rank order correlation was used in analyses. RESULTS: bFGF-containing implants induced MVD of eight, 35, 42, and 42 vessels per square millimeter on days 3, 6, 9, and 12, respectively; in controls, MVD was four vessels/mm2 (P<.05 on days 6, 9, and 12). bFGF-containing implants induced percentage MVA of 2%, 5%, 20%, and 27%, respectively; in controls, it was 0.5% (P<.05). Maximum enhancement was significantly increased in bFGF implants (23.3 gray level+/-14.1 [standard deviation]) compared with controls (11.0+/-5.5, P<.001). Implants containing bFGF showed poor correlations between fractional blood volume and MVD (r2=0.42) or percentage MVA (r2=0.51) at US. There was no correlation between microbubble velocity and MVD (r2<0.05) or percentage MVA (r2<0.13). CONCLUSION: Functional US perfusion parameters do not correlate with current histologic indices for quantifying angiogenesis. MVD, as a histologic quantitative measurement of angiogenesis, may not be an appropriate standard for contrast-enhanced imaging that relies on perfused neovessels.

Animals↗

PubMed2005

CT hepatic venography: 3D vascular segmentation for preoperative evaluation.

Preventing complications during hepatic surgery in living-donor transplantation or in oncologic resections requires a careful preoperative analysis of the hepatic venous anatomy. Such an analysis relies on CT hepatic venography data, which enhances the vascular structure due to contrast medium injection. However, a 3D investigation of the enhanced vascular anatomy based on typical computer vision tools is ineffective because of the large amount of occlusive opacities to be removed. This paper proposes an automated 3D approach for the segmentation of the vascular structure in CT hepatic venography, providing the appropriate tools for such an investigation. The developed methodology relies on advanced topological and morphological operators applied in mono- and multiresolution filtering schemes. It allows to discriminate the opacified vessels from the bone structures and liver parenchyma regardless of noise presence or inter-patient variability in contrast medium dispersion. The proposed approach was demonstrated at different phases of hepatic perfusion and is currently under extensive validation in clinical routine.

Algorithms↗

PubMed2005

Fusion of the planes of the liver: an anatomic entity merging the midplane and the left intersectional plane.

BACKGROUND: Alignment of the gallbladder fossa and the round ligament may be associated with an almost unknown portal vein branching anomaly. STUDY DESIGN: Ultrasonographic imaging allowed detection of this anomaly, which we characterized as fusion of the planes of the liver. When appropriate, additional specific radiologic examinations were performed (CT scanner supplemented with a three-dimensional reconstruction, a biliary cartography, or an angiography). Surgical consequences were studied from this series and from the literature. RESULTS: Seven patients (0.5%) had the following criteria: 1) round ligament, gallbladder fossa, and termination of the portal vein occurring in the same plane; 2) typical portal vein branching, including a right posterior branch, left branches, and a main medial branch terminated by the Rex's recessus; 3) two main hepatic veins without a significant middle hepatic vein; and 4) absence of the horizontal part of the left hepatic duct. Fusion of the planes may have been involved in two cases of iatrogenic bile duct injury and contraindicated a tumor resection and a right-liver donation. A review of the literature revealed that lack of recognition of the fusion of the planes led to a high proportion of surgical iatrogenic injury. Fusion of the planes could result from incomplete development of the central part of the liver, in agreement with embryologic knowledge. CONCLUSIONS: Knowledge of the fusion of the planes by hepato-biliary surgeons is important. This anomaly may lead to serious complications if it remains undetected during liver resection or bile duct surgery.

Adult↗

PubMed2004

Angiogenesis model for ultrasound contrast research: exploratory study.

RATIONALE AND OBJECTIVES: To optimize an angiogenesis model for imaging research that is stable and can be imaged several times over the angiogenic time course. MATERIALS AND METHODS: Mice and rats received two injections of 0.4 mL of extract of basement membrane matrix (Matrigel; Becton Dickinson Labware, Bedford, MA) in the subcutaneous spaces on either side of the spine. One of the two Matrigel plugs in each animal had either 0.1 microg/mL of basic fibroblast growth factor (bFGF) (11 mice), 1.0 microg/mL of bFGF (12 mice, 5 rats), or 1.0 microg/mL of bFGF and 60 U/mL of heparin (11 mice). Three to 12 days after implantation, animals were imaged before and after the administration of up to four injections of 0.1 mL AF0150. Phase inversion imaging was used on a Siemens Elegra (Siemens ultrasound, Issaquah, WA) equipped with a 13 MHz VFX transducer. Three observers subjectively assessed the pattern of enhancement using a four-point scale. The Matrigel plugs were then removed and two observers graded the angiogenic response on a four-point scale. Ten Matrigel plugs, five with 1.0 microg/mL bFGF and five without, were evaluated histologically following immunohistochemical staining with anti-CD31. RESULTS: The angiogenic response was greater in Matrigel plugs with 1.0 than with 0.1 microg/mL of bFGF. Heparin did not increase the angiogenic response. Vessels were predominantly at the periphery of the plugs with variable central penetration. Plugs appeared anechoic and homogeneous on ultrasound. Contrast enhancement within the plug occurred in 44% of mice with an angiogenic response at or after day 6 and the enhancement increased with the angiogenic response. In the others, peripheral enhancement could not be distinguished from the enhancement of surrounding tissues that were also hyperemic. The thicker rat skin interfered with plug assessment. CONCLUSION: A stable angiogenesis model without the complexity of tumors is described. This model offers the opportunity to image the development and/or inhibition of angiogenesis. Neovasculature in Matrigel was detectable using ultrasound contrast. Quantitative studies correlating the degree of enhancement to microvascular density will be determined in subsequent studies.

Animals↗

PubMed2004

Model to quantify lymph node enhancement on indirect sonographic lymphography.

OBJECTIVE: Our goal was to develop a reliable technique that has minimal operator dependence for quantifying lymph node enhancement to test and optimize new sonography contrast formulations. MATERIALS AND METHODS: Twenty healthy rabbits were studied using five agents, labeled A-G. Agents D and E were the same agent and agents F and G were Imagent, studied blindly to test reproducibility. One milliliter of contrast agent was injected into each hind footpad. A 13-MHz transducer was fixed over the popliteal node, which was imaged at a 4.8-MHz central transmit frequency using phase-inversion technology at 100% power and one frame per second. Immediately after each injection, the footpad was massaged 12 times for 30 sec each time and then imaged after each massage to assess the number of times the node could be refilled from each injection. Lymph node video intensity was measured, and the degree of enhancement was evaluated using analysis of variance with the massage number and the agent used as independent variables. RESULTS: Lymph node enhancement was observed after the first massage with all agents. Degree of enhancement was least with agents A and B, intermediate with agents D and F, and greatest with agent C. Agent A was effective after the first two massages, agent B after the first four, agent C after all 12, agent D after the first eight, and agent F after the first nine. Performance of agents D and F was similar to that of their duplicates, E and G. CONCLUSION: We established a reproducible technique to quantify lymph node enhancement that can distinguish between different agents. The differences in performance suggest that it is possible to optimize agent formulation for indirect sonographic lymphography.

Analysis of Variance↗

PubMed2003

Ultrasonographic rotator-cuff changes in veteran tennis players: the effect of hand dominance and comparison with clinical findings.

The aim of this study was to correlate sonographic abnormalities of the rotator cuff with clinical findings in veteran tennis players. One hundred fifty individuals playing competition-level tennis, aged from 35 to 77 years (mean age 55 years), underwent physical and US examinations of their shoulders. The US abnormalities found in the dominant shoulder were compared with those observed in the non-dominant shoulder and in different subsets of players defined by the absence or presence of former and/or current pain. Tears of the long head of the biceps tendon were seen only in dominant shoulders ( n=8), and tears (23 complete and 20 partial) of the supraspinatus tendon were observed in 43 dominant vs 16 (3 complete and 13 partial) contralateral shoulders ( p<0.001). Subscapularis tendon calcifications were depicted in 23 dominant vs 12 contralateral shoulders ( p<0.05). Seventy players had no pain, 49 had former-but-not-current pain, and 31 had current pain. Abnormal thickening (>2 mm) and effusion of the subacromial-subdeltoid bursa and complete tear of the supraspinatus tendon were more frequent in the latter two groups ( p<0.001 and p<0.05), respectively. Although 90% of the players with a complete supraspinatus tear had experienced former pain, no relationship was found between current pain and the presence of a supraspinatus tear or tendon calcification. The rotator cuff may present important asymptomatic lesions, such as complete tears of the supraspinatus tendon or calcifications, that do not prevent the playing competitive tennis. The only US abnormality associated with pain was subacromial-subdeltoid bursa effusion.

Adult↗

PubMed2003

Blood flow quantification with contrast-enhanced US: "entrance in the section" phenomenon--phantom and rabbit study.

PURPOSE: To investigate changes in destruction-replenishment curves (in vitro and in vivo) that result from microbubble destruction in feeding vessels that pass through the imaging plane before microbubbles enter the region of interest (ROI). MATERIALS AND METHODS: During continuous injections of an ultrasonographic contrast agent, nonlinear gray-scale images were obtained in vitro in the longitudinal plane of a renal dialysis cartridge flow phantom (flow rates of 100, 200, and 400 mL/min) and in vivo in the coronal plane of the left kidneys of two rabbits (two kidneys). Destruction-replenishment curves were obtained for the dialysis cartridge in ROIs located immediately after the entrance of the microbubbles into the image plane and further from the entrance, after microbubbles had traveled across the complete length of the imaging plane. Replenishment curves were also obtained from ROIs in the rabbit kidneys at the level of segmental arteries, distal interlobar arteries, and the cortex. RESULTS: The ROIs immediately after the entrance of the microbubbles in the image plane of the dialysis cartridge and in the segmental artery of the kidney followed a typical exponential function, A(1 - e-alphat). Early portions of curves obtained in ROIs filled with microbubbles that had already passed through the image plane of the dialysis cartridge or in the renal cortex were not well described by such a function. The shape of the curve and the variations as a function of flow rate can be explained by means of a mathematical model based on indicator-dilution theory. CONCLUSION: When the feeding vessels of an ROI travel across the ultrasound field before they reach the measurement region, the typical shape of the replenishment curve is modified (reduced velocity parameter and plateau).

Animals↗

PubMed2003

Validation of ultrasound contrast destruction imaging for flow quantification.

Our purpose was to validate in vitro a kinetic flow model based on microbubble signal decay curve. Using a 3.5 MHz transducer and phase-inversion (1.8 MHz central transmit frequency), a renal dialysis cartridge oriented vertically was imaged in the transverse plane as 1:1000 dilution of AF0150 was infused at 50, 100, 200, 300 and 400 mL/min. Ten gray-scale images were acquired at each infusion rate using 2.5, 5 and 10 frames/s at 100%, 40%, 15% or 1% of maximum transmit power. Video-intensity measured on each 10 images was fit to a kinetic model using Sigma Plot that yielded microbubble concentration, velocity and destruction per frame. These were correlated with the experimental conditions. At 100% power, video-intensity on the first frame (microbubble concentration at equilibrium) was similar for all flow and frame rates. The model fit the experimental data for all flows at 10 frames/s and for flows lower than 400 and 100 mL/min at 5 frames/s and 2.5 frames/s, respectively. The calculated flow was similar to the experimental flow rates, regardless of technique (r(2) = 0.98). Microbubble fraction destroyed per frame was similar for all flow and frame rates and increased linearly with transmit power (r(2) > 0.98). These results suggest that using appropriate power and frame rate for a given flow rate, estimates of fractional blood volume, flow and destruction fraction can be calculated from the decay curve using 10 frames that can be acquired in 1 to 4 s.

Contrast Media↗

PubMed2002

Non-invasive detection of liver fibrosis: Is superparamagnetic iron oxide particle-enhanced MR imaging a contributive technique?

The purpose of our study was to evaluate the ability of superparamagnetic iron oxide (SPIO)-enhanced MR imaging to detect liver fibrosis in patients with chronic liver disease and to compare the findings with histopathological data. Sixty-seven patients with chronic hepatitis ( n=58) or focal nodular hyperplasia (FNH; n=9) were studied using a 1.5-T MR system. The protocol included proton density-weighted, T2-weighted spin-echo (SE) and fast SE (FSE) sequences before and after SPIO administration and T2*-weighted gradient-recalled-echo (GRE) sequences after SPIO. Pre- and post-contrast T2-weighted and T2*-weighted sequences were retrospectively evaluated by three independent observers for evidence of non-tumor hypersignal intensities. Three liver patterns were considered: thick reticulations; thin reticulations; and/or multiple areas of hypersignal intensities. Unenhanced or enhanced patterns were compared with histopathological specimens, which had been obtained by percutaneous biopsy of the right lobe within a maximum of 12 months of MR examination. Liver fibrosis was histologically graded using a five-level scale (F0-F4), according to the METAVIR classification. Histopathology demonstrated significant fibrosis (F2-F4) in 57 patients, non-significant fibrosis in 1 patient (F1), and normal liver surrounding FNH in 9 patients (F0). After SPIO administration, at least one pattern of non-tumor hypersignal intensities was seen in 43 (76%) of the 57 patients with F>/=2 with good agreement (kappa=0.68) compared with 2 (20%) of the 10 F0/1 patients ( p<0.01). Attenuated non-homogeneous liver-signal intensities with persistent thick reticulations, thin reticulations, or multiple areas of hypersignals were observed in, respectively, 30, 52, and 56% of patients with F>/=2 with moderate agreement (kappa=0.51). Before SPIO, MR images were positive in 21 of 57 (37%) F>/=2 and zero F0/1 patients. Post-contrast proton-density-weighted and T2*-weighted GRE were the most sensitive sequences for detecting non-tumor hypersignal intensities. In patients with chronic liver diseases, SPIO-enhanced MR imaging exhibits non-tumor hypersignal intensities indicative of liver fibrosis by decreasing the signal from the non-fibrotic areas where Kupffer cells are present.

Adult↗