Search PubMed⌕ Search

Biomedical subjects

P Gailloud

Publications and source records attributed to P Gailloud.

At least 37 records · Page 2Linked to original sources
PubMed2000

Endovascular treatment of a grade IV transverse sinus dural arteriovenous fistula by sinus recanalization, angioplasty, and stent placement: technical case report.

OBJECTIVE AND IMPORTANCE: The frequent association of dural arteriovenous fistulae (DAVFs) and dural sinus thrombosis may render the treatment of these complex lesions difficult. We report a case of DAVF eradicated by recanalization of the chronically thrombosed transverse sinus (TS) and sigmoid sinus followed by balloon angioplasty and stent deployment at the site of the fistula. CLINICAL PRESENTATION: A 52-year-old man presented with a Type IV DAVF of the left TS with widespread white matter changes secondary to venous hypertension. Arterial feeders arose from the left internal carotid, external carotid, and vertebral arteries. The distal segment of the left TS, the left sigmoid sinus, and the proximal segment of the right TS were occluded. Reverse flow was observed in the deep venous system and in the superior sagittal sinus. INTERVENTION: Endovascular access was gained through the left internal jugular vein. Mechanical recanalization of the thrombosed left TS and sigmoid sinus was followed by balloon angioplasty and placement of six overlapping stents extending from the TS to the proximal internal jugular vein. Angiograms performed after surgery showed resaturation of antegrade venous drainage as well as complete eradication of the fistulous connections. The patient was discharged with an improving clinical CONCLUSION: Recanalization of a chronically occluded dural venous sinus through a jugular approach is feasible. In addition to eradicating cerebral venous hypertension by reestablishing antegrade venous drainage, balloon angioplasty and stent deployment at the DAVF site produced complete closure of the fistula. This may prove to be a new therapeutic strategy for management of DAVF.

Angiography, Digital Subtraction↗
PubMed2000

Neurovascular embolization: in vitro evaluation of a mechanical detachable platinum coil system.

The authors evaluated a mechanically detachable platinum coil system intended for neurovascular use. The introduction characteristics, ease of delivery, ease of retrieval, and detachability were studied with fluoroscopic guidance with in vitro silicone models. All the coils passed easily through the microcatheter. The detachment maneuver occurred within 20 seconds with 20 or fewer rotations of the pusher wire. One of 229 coils detached prematurely but only after deliberate and extreme manipulation. The detachment system is safe, reliable, and consistent and will be useful for interventional neuroradiologists.

Cerebrovascular Disorders↗
PubMed2000

The effect of contrast material on transcranial Doppler evaluation of normal middle cerebral artery peak systolic velocity.

BACKGROUND AND PURPOSE: Several recent studies have shown that sonographic contrast agents may affect transcranial Doppler evaluation of the arterial peak systolic velocity (PSV). Some investigators reported an increase in PSV, and others reported no change in PSV compared with baseline values. This study was conducted to determine the effect of sonographic contrast agent on PSV measured in normal middle cerebral arteries. METHODS: Continuous spectral Doppler sonography was performed on the right middle cerebral artery of 20 participants with angiographically proven normal intracranial vasculature. Videotaping was performed in each case from the initiation of the administration of contrast medium until the effect of the contrast agent on the PSV subsided. The PSV values were normalized for each participant, were pooled, and were plotted as a function of time. RESULTS: PSV increased in all participants after the administration of contrast material; the mean maximum increase was 24+/-7.4% (mean +/- standard deviation) (range, 15-36%). The mean duration of PSV increase was 320+/-97 s (range, 165-465 s). CONCLUSION: The middle cerebral artery PSV increased substantially after the administration of contrast material. This effect needs to be considered if velocity thresholds developed for disease detection without the use of contrast materials are used when contrast agents are administered.

Adolescent↗
PubMed2000

Dense packing of cerebral aneurysms: an in vitro study with detachable platinum coils.

Aneurysm models were used to study the density of packing after coil embolization. Platinum coils were introduced until the point of minimally dense packing, indicated by aneurysmal circulatory exclusion. Packing was continued up to the point of maximal density, indicated by protrusion into the parent artery. Volumetric ratios (coil volume/aneurysmal volume) were calculated for minimally and maximally dense packing. Maximally dense packing ratios were a little higher than the minimally dense ratios, but less than 37%.

Implants, Experimental↗
PubMed1999

Laterocavernous sinus.

Here we describe an anatomic structure that takes the form of a venous channel (VC) within the two layers of the lateral wall of the cavernous sinus (CS). Colored gelatin was injected in both superficial middle cerebral veins (SMCV) of 29 human specimens. When a SMCV terminated into the CS, the latter was dissected giving particular attention to its lateral wall. The termination of the VC and its eventual communications with the CS and adjacent venous structures were studied. A VC in the lateral wall of the CS was found in 14 of 58 lateral walls (24.1%). It was in continuation with the SMCV in 13 cases, with the uncal vein in one case. The VC drained into the superior petrosal sinus (71.4%), the pterygoid plexus (21.4%), or the posterior part of the CS (7.2%). Two alternate drainage pathways for the SMCV were observed, toward the anterosuperior aspect of the CS (13.8%) or through a paracavernous sinus located along the floor of the middle cranial fossa (32.8%). These different pathways were not observed to occur concomitantly. SMCV were absent in 29.3%. Despite its close topographic relation with the CS, the VC in the lateral wall can be considered as an anatomic entity with potential clinical relevance. We propose to call it the laterocavernous sinus.

Adult↗
PubMed1999

Anatomy teaching for medical undergraduates: general practice as a guideline? The brain.

Basic science teaching, particularly the teaching of gross anatomy, is at present a highly controversial topic. How much and what kind of anatomy should be taught to medical undergraduates nowadays? In conducting the present study we based our proposals on the criterion of general medical relevance. Therefore, we sent an anatomical questionnaire to a sample of Swiss general practitioners. Here, we present the results derived from questions on the human brain, discussing them in connection with the other organs so far investigated. The results obtained suggest that a common body of anatomical knowledge appropriate for the field of general medical practice does in fact exist. We believe that this basic stock can serve as a guideline for decision makers involved in the development of curricula, which can be fitted into the time frame available for anatomy teaching today while still guaranteeing a sound level of competence required for general practice of medicine. We also hope that this approach may serve as a model for the teaching of other basic sciences.

Anatomy↗
PubMed1999

Twinkling artifact on intracerebral color Doppler sonography.

Transcranial Doppler sonography shows potential as a noninvasive technique for long-term follow-up of treated intracranial saccular aneurysms. This technical note describes a color Doppler artifact related to microcoil architecture that might represent a potential pitfall in transcranial Doppler sonographic evaluation of aneurysmal cavity thrombosis, since it may be wrongly interpreted as residual flow or aneurysmal cavity recanalization.

Angiography, Digital Subtraction↗
PubMed1999

In vitro models of intracranial arteriovenous fistulas for the evaluation of new endovascular treatment materials.

BACKGROUND AND PURPOSE: The purpose of this study was to create and test an in vitro model of intracranial arteriovenous fistulas (AVFs) that simulates the geometry of human vasculature and allows realistic testing of devices used in endovascular therapy. METHODS: The models were derived from corrosion casts of the main cervicocranial arteries and veins obtained from two nonfixed human specimens. Wax copies of the casts were produced and combined to create complex models simulating various types of intracranial AVFs. Wax assemblies were embedded with liquid silicone solidified into transparent blocks containing, after wax evacuation, hollow reproductions of the original vascular trees. The models were connected to a pulsatile pump and their compatibility with various imaging techniques and endovascular treatment materials was evaluated. RESULTS: The models were compatible with digital subtraction angiography, CT, MR imaging, and transcranial Doppler sonography. They provided a realistic endovascular environment for the simulation of interventional neuroradiologic procedures. CONCLUSION: Anatomically accurate and reproducible in vitro models of intracranial AVFs provide a valuable method for evaluating new endovascular treatment materials and for teaching purposes.

Aged↗
PubMed1998

Epidermoid cyst of the skull with nonpulsatile tinnitus.

We report an intradiploic epidermoid cyst of the skull responsible for transverse sinus compression and presenting with nonpulsatile tinnitus. Plain films and CT both demonstrated the tumour. Cerebral angiography showed best the degree of narrowing of the right transverse sinus, accompanied with turbulent flow probably leading to tinnitus. MRI demonstrated accurately both the tumour and the dural sinus compression. The tumour was totally removed, cranioplasty was performed, and the patient was discharged free of symptoms.

Adult↗
PubMed1998

Second-generation three-dimensional reconstruction for rotational three-dimensional angiography.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the feasibility and accuracy of three-dimensional (3D) reconstruction techniques for digital subtraction angiography (DSA) in planning and evaluation of minimally invasive image-controlled therapy. MATERIALS AND METHODS: Using a standard, commercially available system, the authors acquired DSA images and corrected them for inherent distortions. They designed and implemented parallel and multiresolution versions of cone-beam reconstruction techniques to reconstruct high-resolution targeted volumes in a short period of time. Testing was performed on anatomically correct, calibrated in vitro models of a cerebral aneurysm. These models were used with a pulsatile circulation circuit to allow for blood flow simulation during DSA, computed tomographic (CT) angiography, and magnetic resonance (MR) angiography image acquisitions. RESULTS: The multiresolution DSA-based reconstruction protocol and its implementation allowed the authors to achieve reconstruction times and levels of accuracy for the volume measurement of the aneurysmal cavities that were considered compatible with actual clinical practice. Comparison with data obtained from other imaging modalities shows that, besides vascular tree depiction, the DSA-based true 3D technique provides volume estimates at least as good as those obtained from CT and MR angiography. CONCLUSION: The authors demonstrated the feasibility and potential of true 3D reconstruction for angiographic imaging with DSA. On the basis of the model testing, this work addresses both the timing and quantification required to support minimally invasive image-controlled therapy.

Algorithms↗
PubMed1998

Segmental anatomy of the liver: poor correlation with CT.

PURPOSE: To evaluate qualitatively and quantitatively the current procedures for radiologic delineation of the segmental and subsegmental anatomy of the liver. MATERIALS AND METHODS: Vascular casts of 10 livers were examined with helical computed tomography (CT). Liver segmental and subsegmental anatomy were determined on the CT scans according to customary radiologic practice guidelines. CT anatomic findings were compared with authentic anatomic territories seen at anatomic examination. The differences were assessed quantitatively in five of the 10 livers. RESULTS: For the marginal (cranial and caudal) portions of the liver, an average (+/- 1 standard deviation) of 17.3% +/- 6.5 of the hepatic area visualized on axial CT scans was attributed to an incorrect subsegment. For the central zones (those adjacent to the right and left branches of the portal vein), this error amounted to 51.6% +/- 19.9. Expressed in absolute numbers, the error amounted to 40 mm on axial CT scans. CONCLUSION: The radiologic determination of portal venous territories within the liver must be revised. The indirect landmarks currently used are not reliable for proper delineation. Only procedures that account for the portal venous distribution pattern, including peripheral branches, will result in correct depiction of the complex and variable anatomic reality.

Aged↗
PubMed1997

Termination of the inferior petrosal sinus: an anatomical variant.

Unusual caudal terminations of the inferior petrosal sinus (IPS) characterized by an extracranial extension joining the internal jugular vein up to 40 mm below the external skull base are reported. This variation was observed bilaterally on an anatomical specimen and unilaterally on four patients during diagnostic cerebral angiography. It may be considered an accessory internal jugular vein and, if present, may allow for an alternate endovascular access to the IPS.

Adult↗
PubMed1997

Liver of the "visible man".

Endoscopic surgery, also called minimally invasive surgery, is presumed drastically to reduce postoperative morbidity and thus to offer both human and economic benefits. For the surgeon, however, this approach leads to a number of gestural challenges that require extensive training to be mastered. In order to replace experimentation on animals and patients, we developed a simulator for endoscopic surgery. To achieve this goal, a first step was to develop a working prototype, a "standard patient," on which the informatic and microengineering tools could be validated. We used the visible man dataset for this purpose. The external shape of the visible man's liver, his biliary passages, and his extrahepatic portal system turned out to be fully within the standard pattern of normal anatomy. Anatomic variations were observed in the intrahepatic right portal vein, the hepatic veins, and the arterial blood supply to the liver. Thus, the visible man dataset reveals itself to be well suited for the simulation of minimally invasive surgical operation such as endoscopic cholecystectomy.

Adult↗