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Biomedical subjects

M T Farres

Publications and source records attributed to M T Farres.

10 recordsLinked to original sources
PubMed2001

Evaluation of renal arteries with use of gadoterate meglumine-, CO(2)-, and iodixanol-enhanced DSA measurements versus histomorphometry in renal artery restenosis in rabbits.

PURPOSE: To experimentally evaluate gadolinium (Gd)-, carbon dioxide (CO(2))-, and iodixanol-enhanced digital subtraction angiography (DSA) versus histomorphometry in the assessment of renal artery stenosis. MATERIALS AND METHODS: Fifteen male New Zealand White rabbits weighing 4.0 kg underwent percutaneous catheterization. Renal artery stenosis was induced by bilateral overdilation-deendothelialization (balloon diameter = 2 mm). The percentage of artery overdilation was 33%. After 4 weeks, the rabbits were randomized into two groups: group A underwent right-sided therapeutic percutaneous transluminal renal angioplasty (PTRA) (balloon diameter = 1.5 mm). After another 4 weeks, the renal arteries were evaluated by gadoterate-, iodixanol-, and CO(2)-enhanced selective quantitative DSA. The rabbits were then killed and renal arteries were perfusion-fixed for 60 minutes. Serial orcein-stained 4-um-thick slices were prepared for histomorphometry. RESULTS: Based on morphometric data of single-stenosis versus post-PTRA restenosis lesions, no significant difference was observed between Gd- and iodixanol-enhanced quantitative DSA (r(2) > 0.95), although the iodine/Gd density ratio was equal to 3.5. Carbon dioxide less reliably allowed quantitative DSA (r(2) < 0.75). CONCLUSION: Gd-based contrast agents represent a highly reliable alternative in experimental quantitative DSA evaluation of renal artery restenosis.

Angiography, Digital Subtraction↗
PubMed2000

Pulmonary arteriovenous malformations.

OBJECTIVE: Helical CT scan (HCT), a noninvasive method, can detect pulmonary arteriovenous malformations (PAVMs). Its sensitivity is superior to that of global digitalized angiography, but patients receive a significant dose of radiation during diagnostic HCT. We compared HCT to contrast-enhanced pulmonary magnetic resonance angiography (CEMRA), a new noninvasive radiation-free method, in the diagnosis of PAVMs. PATIENTS AND METHODS: Five consecutive patients with PAVMs underwent HCT, CEMRA, and pulmonary artery digital subtraction angiography (PADSA). CEMRA was performed during the pulmonary arterial phase of an IV bolus of gadolinium. PADSA was performed during the embolization procedure. All images were examined for PAVMs. The site and size of aneurysms were specified, as well as the diameter of the vascular pedicles. RESULTS: Thirty PAVMs were detected by CEMRA and 38 by HCT. All 20 PAVMs at least 5 mm in diameter and 10 of the 18 PAVMs < 5 mm in diameter identified on HCT were also identified by CEMRA. Whatever the site, all PAVMs with a feeding artery diameter of at least 3 mm (ie, PAVMs with clinical consequences) were detected by CEMRA. No false-positive results were obtained with CEMRA. CEMRA therefore had a sensitivity of 78% and a specificity of 100%. CONCLUSIONS: CEMRA, a nonionizing and noninvasive procedure, has high sensitivity and specificity for the diagnosis of clinically relevant PAVMs.

Adult↗
PubMed2000

Nonnephrotoxic, dynamic, contrast enhanced magnetic resonance urography: use in nephrology and urology.

PURPOSE: We assessed the value of breath-hold, gadolinium (Gd) enhanced magnetic resonance urography for diagnosing urinary tract disease. MATERIALS AND METHODS: Dynamic magnetic resonance urography was performed in 38 consecutive patients presenting with urological disease in whom excretory urography was contraindicated. Renal function was impaired in 18 cases with a serum creatinine of 140 to 400 micromol./l. Fast spoiled, gradient echo sequences were acquired during breath-holding 5, 10 and 15 minutes after intravenous injection of 10 ml. of a Gd chelate. Opacification of the collecting system was evaluated using a scale of 0 to 3. Diagnostic value of the examinations was also analyzed. RESULTS: Dynamic magnetic resonance urography was sufficient for making the diagnosis in 95% of cases. We identified 71 pathological findings and the surgical anastomosis was always well visualized. Mean image quality score was 2.34 points for renal calices, 2.86 for renal pelves and 2.48 for ureters. Image quality significantly improved after injecting a diuretic. CONCLUSIONS: Gd enhanced magnetic resonance urography provides quality dynamic imaging of the urinary tract. It is a new approach for diagnosing urinary tract disorders in patients in whom excretory urography should be avoided.

Adult↗
PubMed1999

[Magnetic resonance angiography (MRA) of the abdominal aorta and its branches].

Technical aspects of 3D contrast-enhanced magnetic resonance angiography are exposed, detailing more particularly the pulse sequence used and the mode of injection of contrast agent. Then, various vascular territories are analyzed, and illustrated using various examples of main pathologies observed in routine clinical practice: abdominal aorta, renal arteries, pelvic and mesenteric vessels, and peripheral arteries.

Aneurysm↗
PubMed1997

[Cowper's gland: anatomic, physiological and pathological aspects].

Cowper's glands are small appendages of the male genital tract, that are sometimes observed on intravenous urography voiding films. They are involved in the immune defence of the genitourinary tract, play a role in fertility, and secrete many glycoproteins, including PSA. They can be visualized in the form of a duct image parallel to the urethra, sometimes associated with opacification of the gland on IVU. This image can be differentiated from a fistula, extravasation of contrast agent, urethral duplication, or an artefactual image, by the course parallel to the urethra, the upper limit not exceeding the urogenital diaphragm, and the position of the orifice. These glands can be affected by neoplastic, infectious, stone and especially cystic disease: syringocele. The physician should think of these glands in patients with unusual genitourinary symptoms in order not to miss disease of these organs, and to prescribe appropriate treatment.

Bulbourethral Glands↗
PubMed1996

[Contrast media in peripheral angiography: does cost reduction mean loss of quality and safety? A reevaluation based on a randomized double-blind comparative study of ioxaglate versus iopromide].

PURPOSE: To evaluate whether meglumine-sodium-ioxaglate (Hexabrix) and iopromide (Ultravist) are identically appropriate for peripheral angiography. Outcome variables were pain, image quality and adverse events. METHODS: Sixty patients were included in a randomised double-blind study. In all patients an intraarterial digital subtraction angiography (i.a. DSA) of iliac and peripheral arteries was performed. RESULTS: Analysis of the study revealed no significant difference between both contrast media in terms of the main and additional outcome variables. In comparison to iopromide, ioxaglate caused milder pain sensations (VAS 4.70 vs. 7.76, p = 0.25). Mild adverse events were observed more frequently in ioxaglate angiography (11% vs. 0%, p = 0.1). CONCLUSION: Both contrast media seem to be appropriate for peripheral angiography using DSA technique. Ioxaglate causes a cost reduction of about 20-35%. However, an increase of mild adverse reactions up to 11% to 15% has to be accepted.

Adult↗
PubMed1994

Preoperative staging of osteosarcoma: efficacy of MR imaging in detecting joint involvement.

OBJECTIVE: Selecting the appropriate surgical procedure for treatment of patients with osteosarcoma requires accurate preoperative evaluation of tumor extent. Establishing the presence or absence of joint involvement is particularly important. Accordingly, we studied the efficacy of MR imaging for detecting joint involvement in 46 patients with osteosarcoma around joint spaces. SUBJECTS AND METHODS: Preoperative MR examinations were performed in 46 consecutive patients with osteosarcoma whose tumors were located around the knee (n = 33), the hip (n = 8), or the shoulder (n = 5). T2-weighted and unenhanced and contrast-enhanced T1-weighted spin-echo MR images were obtained for all patients. We assessed the presence or absence of tumor invasion of the intracapsular-intrasynovial joint space, either by disruption of the joint capsule or by intraarticular destruction of the cortical bone and articular cartilage or the intracapsular-extrasynovial cruciate ligaments of the knee. All patients subsequently had surgery. The MR findings were correlated with findings from macroscopic and microscopic pathologic examinations. RESULTS: All 10 patients who subsequently proved to have tumor involvement of the joint were correctly identified (sensitivity, 100%). The tumor involved the knee joint in seven patients, the hip joint in two, and the shoulder joint in one. However, the MR diagnosis was false-positive in another 11 patients who did not have joint involvement at surgery (specificity, 69%). In the knee, MR imaging was more accurate in identifying tumor extension to the cruciate ligaments than to the intrasynovial joint space. Post-contrast T1-weighted images were most useful in detecting joint involvement. CONCLUSION: MR imaging is highly sensitive for detecting joint invasion of osteosarcoma. However, false-positive diagnoses may lead to overstaging of tumor and result in unnecessarily radical surgical procedures.

Adolescent↗
PubMed1993

[Stenoses and occlusions of the abdominal aorta in patients less than 40-years old].

Stenosis or occlusion of the abdominal aorta in patients under 40 years of age is either due to a congenital malformation (abdominal aortic coarctation) or due to idiopathic aortitis (Takayasu's arteritis). Some authors, however, consider abdominal aortic coarctation as a subtype of Takayasu's arteritis. We evaluated 9 of our cases and 108 well-documented cases from the literature to help decide the question whether abdominal aortic coarctation is an entity of its own or a subtype of Takayasu's arteritis. In coarctation there is a slight male predominance, patients are usually younger than 20 years of age, and the short aortic stenosis is suprarenal with involvement of the renal arteries. In Takayasu's arteritis females are predominantly affected, patients are usually over 20 years of age, and the long aortic stenosis or occlusion is infrarenal without involvement of the renal arteries. Abdominal aortic coarctation must therefore be considered as a separate disease. Aortography is important, because the morphology of aortic alterations often allows a radiological diagnosis.

Adult↗