Biomedical subjects

F J Fernández Mena

Publications and source records attributed to F J Fernández Mena.

3 recordsLinked to original sources

PubMedDate not supplied

[Bladder cancer].

OBJECTIVE: For optimum treatment planning and to establish the prognosis, the main objectives of diagnostic imaging techniques after detecting a tumor in the urinary bladder are to determine 1) its nature and histological structure, 2) depth of bladder wall invasion, 3) tumor localization and involvement of the ureter and trigone, 4) involvement of bladder wall lymphatics, and (5) to determine if there is or no regional and/or distant mestatasis. The capabilities of the diagnostic imaging techniques in regard to achieving the foregoing objectives are analyzed. METHODS: This study comprised 160 patients with a suspected or confirmed bladder tumor. The imaging methods utilized were: conventional radiology including IVP, retrograde and double contrast cystography, ultrasound, CT and MRI. RESULTS: Analysis of the images allowed assessment of 18 morphological parameters, of which the following were among the most relevant: presence of ureterohydronephrosis, filling defect(s), tumor localization, tumor base, tumor-mucosa angle, wall stiffness, total wall thickness, changes observed in the perivesical space and degree of pelvic lymph node involvement. Visualization of a bladder filling defect confirms a bladder tumor. The predictors of the biological behaviour of bladder tumors, such as wall stiffness and lumen asymmetry, characteristically express tumor invasiveness. The tumor-mucosa angles in relation to tumor base and peritumoral edema express a higher grade of infiltration for the obtuse angles and a lower grade for the acute angles. Determining tumor stage with accuracy is the essential challenge of the imaging methods in the assessment of bladder cancer. Both CT and MRI are used to analyze four basic aspects prior to treatment: 1) tumor appearance, 2) presence or absence of perivesical invasion, 3) presence or absence of invasion of the adjacent organs, and 4) presence or absence of lymphadenopathies. The accuracy of CT for tumor staging is estimated to be 88%-92% for stage D1 and 80%-85% for stages C and B2, respectively, while MRI has an accuracy of 95% for stage B2 and 85% for tumor stages that compromise adjacent organs such as the prostate, uterus or vagina. CONCLUSIONS: Conventional radiological methods, together with transabdominal or transrectal ultrasound, have a high rate of accuracy for tumor detection. Determination of the stage of tumor invasion requires analysis of wall thickness, width of tumor base, tumor-mucosa angles and perivesical space. CT and MRI provide highly reliable diagnostic information on the foregoing. CT may present some difficulty in determining the stage of bladder wall invasion. With contrast enhancement, MRI has shown a greater capability to differentiate tumor stages B2 and C and is very similar to CT in detecting pelvic or retroperitoneal lymph node involvement.

History, 19th Century↗

PubMedDate not supplied

[Renal cancer].

OBJECTIVES: This study was carried out 1) to analyze the growth and clinical manifestations of renal adenocarcinoma; 2) to determine the presence of tumor, its malignant nature, size, local extent or distant spread and route of dissemination according to the imaging methods utilized, and 3) to determine the accuracy of the different imaging procedures, such as IVP, US, CT, and MRI, in staging renal adenocarcinoma. These objectives attempted to provide answers to the following questions: a) Are there currently substantial changes in the biological behavior of renal adenocarcinoma?, b) Does the route of tumor dissemination (direct infiltration through the capsule, lymphohematogenous, cancer embolus carried by the bloodstream to a distant location) affect the rate of progression to stages III and IV?, and c) What are the most relevant findings of the imaging methods that aid in determining the extent of the renal tumor? METHODS: 106 renal masses were evaluated; of these, 93 were renal adenocarcinomas. The diagnosis, clinical evaluation and preoperative staging were based on the clinical history, physical examination, symptoms and imaging methods (IVP, US, CT, and MRI) to assess renal morphological changes, presence of calcifications, mass effect, tumor mass ultrasound characteristics, densitometry or MR signal pattern, perinephric fat involvement, venous vasculature, involvement of renal fascia, locoregional lymph nodes or metastasis and distant neoplastic changes. RESULTS: A third of the tumors had a size greater than 10 cms and practically half were 5-10 cms in size. Calcifications were found in 47%; 85% were punctiform and showed a central location. 88% of the tumors showed areas of necrosis. Due to the presence, in most of the cases, of a viable tumor, necrosis, calcification or cystic degeneration, the adenocarcinomas showed a very inhomogeneous ultrasound pattern and with varying degrees of vascularization on CT volumetric assessment. Invasion of perinephric fat and tumor fibrous septae were found in 65% on CT evaluation, although MRI was particularly sensitive in detecting fat infiltration in the early stages of perinephric involvement, venous thrombosis, involvement of adjacent and distant organs and tumor hemorrhagic changes. CONCLUSIONS: In determining the biological behaviour of renal adenocarcinoma, preoperative staging of infiltration and prognosis, US, volumetric CT and MRI are currently the diagnostic methods with the highest accuracy, specificity and sensitivity. These diagnostic methods allow early detection of tumors thereby making them potentially curable. Lymphatic drainage of the tumor may be determinant in its more or less rapid progression from Robson stage II to IIIa and IIIb, and thereafter to stage IV. CT and MRI showed a higher accuracy for tumor detection, localization, determining local extent, tumor characterization and staging. Detection of a tumor pseudocapsule comprised of reactive fibrous tissue and compact renal parenchyma by CT or MRI allows determination of the borders of the renal tumor. Lymph node involvement radically changes the prognosis and survival in renal adenocarcinoma.

Adenocarcinoma↗

PubMedDate not supplied

[Densitometric study of staghorn lithiasis using computerized tomography].

Fifty staghorn calculi that had been removed surgically and previously analyzed for stone composition and structure were studied by tomodensitometry. The analysis consisted of measurements in absolute units and histographic configuration of x-ray attenuation-absorption of the lithiasic material. The reconstructed images were evaluated and the areas of interest were defined. Each section and area had the following universal elements: number of pixels studied and values for mean attenuation expressed as Hounsfield units (HU). In this manner, tomodensitometric mapping of the calculi could be performed. We underscore the usefulness of this procedure in investigation and the possibility of extrapolating the results to in vivo studies of calculi composition so that we can reliably predict the results attainable with treatment modalities such as ESWL or percutaneous surgery. Little has been published on this subject. To our knowledge, this is the first in Spain.

Densitometry↗