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M Cova

Publications and source records attributed to M Cova.

40 records · Page 3Linked to original sources

[Computed tomography and magnetic resonance in the preoperative staging of the spread of rectal cancer. A correlation with the anatomicopathological aspects].

In order to assess the accuracy of CT and MRI in evaluating the local extent of rectal carcinoma, 22 patients with a rectoscopic diagnosis of rectal cancer were examined before surgery with both techniques. Tumor extent into the perirectal fat, involvement of surrounding structures and local adenopathy were evaluated on both CT and MR images. These findings were compared with the micro- and macrohistologic findings obtained from the surgical specimens. As far as perirectal fat infiltration is concerned, the diagnostic accuracy of CT was 73% and that of MRI was 71%. Sensitivity was 100% for CT and 91% for MRI, while specificity was low for both techniques (45% for CT and 50% for MRI). In evaluating local adenopathy, CT accuracy was 82% and MR accuracy was 90%, with 89% sensitivity for both techniques and 77% specificity for CT and 92% for MRI. The overall accuracy was 59% for CT and 67% for MRI. In agreement with literature data, our study shows a similar accuracy for CT and MRI in evaluating the local extent of rectal carcinomas. Moreover, our results confirm the value of macrohistology in the local staging of rectal carcinoma and its prognostic value, as well as the low specificity of both CT and MRI in evaluating lesion spread into the perirectal fat.

Aged↗

[Morpho-functional study of the kidney in patients with kidney disease and liver disease with magnetic resonance].

INTRODUCTION: We studied renal function and perfusion after the i.v. injection of Gd-DTPA-BMA, a nonionic paramagnetic contrast agent, to assess renal morphology and function in normal subjects, in renal insufficiency patients and in patients with hepatic failure and normal renal function. The latter were chosen because some patients with advanced hepatic failure may suffer from the hepatorenal syndrome, characterized by severe vasoconstriction in the renal cortical vessels. We investigated if dynamic MRI can detect early renal perfusion abnormalities in the patients who will eventually develop this syndrome. MATERIAL AND METHODS: Thirty MR examinations were carried out on 30 subjects after the i.v. injection of Gd-DTPA-BMA. Our series consisted of: 10 normal subjects; 10 renal insufficiency patients; 10 patients with hepatic failure and normal renal function. MR examinations were performed on a Philips ACS II scanner operating at 1.5 T. Two sequences were carried out in all cases: T1-weighted SE and T1-weighted TGE sequences after the bolus injection of .1 mmol/kg contrast agent. Renal longitudinal diameter and parenchymal thickness were measured in all cases and signal intensity time curves were always made. The signal intensity of the cortex, corticomedullary junction, medulla and pyelocaliceal system of each kidney was measured using a region of interest (ROI). The signal intensity curves were made considering quantitative parameters, including the area below the curve (ASC), the peak (P) and the time to peak (T-P). RESULTS: Longitudinal diameter and parenchymal thickness values were significantly lower in renal insufficiency patients than in normal subjects. Four phases were demonstrated after i.v. contrast agent injection in normal subjects, namely A) the cortical phase, B) the corticomedullary junction phase, C) the medullary phase, D) the pyelocaliceal phase. No signal intensity decrease in the medullary and pyelocaliceal curves was observed in renal insufficiency patients. Signal intensity curves values were lower in hepatic failure patients than in those with normal renal function. Hepatic failure patients could be divided into two groups: 5 patients had low P and ASC values and 4 had normal P and ASC values. The patients with lower P and ASC values developed the hepatorenal syndrome within a few months of the MR examination. DISCUSSION: Signal intensity decreased in the pyelocaliceal system phase in normal subjects because of the high paramagnetic contrast agent concentration. The lack of signal intensity decrease in renal insufficiency patients was caused by the reduced capability of concentrating Gd-DTPA-BMA. Lower signal intensity values in hepatic failure patients may be considered an early sign of the hepatorenal syndrome.

Adult↗

[Virtual endoscopy of the nasal cavity and the paranasal sinuses with computerized tomography. Anatomical study].

INTRODUCTION: Virtual endoscopy is a new 3D technique which permits to depict the inner surface of anatomic cavities. We report our experience in the study of the nasal cavity and paranasal sinuses. MATERIAL AND METHODS: CT examinations of the maxillofacial region were obtained using 1.5 or 3.0 mm slices, 1.5 or 3.0 mm table feed, 120 kV, 140 mA, 2 s scan time, standard and high resolution algorithms for bony structures and a field of view of 14-16 cm. The images were transferred on a workstation and processed with the Navigator virtual endoscopy software (General Electric). A threshold value ranging -300 to -550 UH was applied. RESULTS: We report a series of virtual images of the nasal cavity which includes rhinopharynx vault, torius tubarius, choanae, turbinates, tubal orifice and osteomeatal complex. Moreover, images of frontal sinus and tear duct, of polyps and fracture of maxillary sinus are also presented. 3D virtual endoscopy provides a clear visualization of the anatomic structures of the nasal cavity and sinuses. The images are similar to those of conventional endoscopy. Moreover virtual endoscopy visualizes the paranasal sinuses, which are not accessible at conventional endoscopy. The main limitations of this new technique are the arbitrary choice of the threshold value and the homogenization of different tissue densities, which reduces the contrast resolution. CONCLUSIONS: Virtual endoscopy can presently be considered a complementary technique of the standard axial and coronal CT examination. It provides an effective demonstration of the anatomy of these structures and shows areas which are difficult to visualize with conventional endoscopy. This technique could be of help in didactical activity; its clinical application has to be verified.

Humans↗