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Biomedical subjects

C Matos

Publications and source records attributed to C Matos.

At least 91 records · Page 5Linked to original sources

Development of the hypodysplastic kidney: contribution of antenatal US diagnosis.

Two cases of fetal perirenal uriniferous pseudocyst were diagnosed in utero with ultrasound studies. The perirenal collections resolved spontaneously in utero. Follow-up examination showed growth impairment of the affected kidney. At birth, no renal function was demonstrated in one case and only slight function in the other case. Pathologic examination showed a highly dysplastic kidney with extravasated urine in the case in which surgery was performed. Some hypodysplastic kidneys apparently result from acute in utero obstruction with secondary pyelocalyceal rupture. Renal dysplasia could render the kidney more vulnerable to such phenomena.

Adult↗

Total parenteral nutrition (TPN) and gallbladder diseases in neonates. Sonographic assessment.

During a 1-year period, a prospective ultrasound (US) study of the biliary tract was performed in 41 neonates receiving total parenteral nutrition (TPN). Gallbladder sludge appeared in 18 neonates (44%) after a mean period of 10 days of TPN. The occurrence of this abnormality seems related to three main factors: prematurity with immaturity of the enterohepatic circulation of bile acids, duration of TPN, and lack of enteral nutrition. In five neonates (12%), an evolution of sludge to "sludge balls" was observed. Two neonates (5%) went on to develop uncomplicated gallstones and a spontaneous resolution occurred in one of them 6 months after the examination. This finding suggests conservative management in such cases. However, since cholecystitis or biliary tract obstruction are classical complications in older children, a US survey of neonates receiving TPN is useful to follow the abnormal gallbladder content, and rapid introduction of enteral feeding is advisable.

Cholelithiasis↗

[Magnetic resonance imaging, with surface coil, of a transplanted kidney].

MR appearance of the kidney transplant is evaluated on a series of 80 examinations performed on a supraconductive unit operating at 0.5 T. Normal function kidneys displayed a clearly delineated corticomedullary differentiation (CMD); the ratio between the thickness of cortex and medulla didn't exceed 0.6. The same appearance was observed in non complicated acute tubular necrosis. Complete loss of CMD was the major finding in acute rejection (74% of the cases), but it was not specific as it was also observed in chronic rejection and in acute glomerulonephritis. Cortex thickening was helpful for the detection of rejected transplants with visible CMD. The sensitivity of MR in the detection of acute rejection was 94%. Specificity of MR findings for acute rejection depended on the transplant age: it varied from 100% for examinations performed during the first 3 months after transplantation, to less than 50% for examinations of the second year.

Acute Disease↗

Mesenteric vein thrombosis: early CT and US diagnosis and conservative management.

We report a case of isolated superior mesenteric vein thrombosis with acute ischemic bowel disease, diagnosed early by a screening ultrasound scan of the upper abdomen and definitively assessed by computed tomography and angiography. This report stresses the contribution of cross-sectional techniques in the early diagnosis and management of venous occlusive disease of the small bowel.

Female↗

Sonographic demonstration of malabsorption in neonates.

A new sonographic pattern is described that has been found in eight infants having syndromes associated with malabsorption. Five infants had hepatobiliary disease and three infants had transient or permanent cow-milk intolerance. In all cases, upper abdominal sonographic examinations revealed hyperechoic tubular and round masses which, most probably, represent small bowel loops filled with malabsorbed milk. Control examinations, before hepatic failure or under corrected diet, showed absence of the pattern. It is believed by the authors that in some ambiguous cases, the finding of this pattern should direct the pediatrician toward syndromes associated with malabsorption.

Bile Ducts↗

Lithiasic complications of renal transplantation: the donor graft lithiasis concept.

Lithiasis is usually a late complication of renal transplantation reported in approximately 1% of all renal allografts. Underlying predisposing conditions for the formation of calculi are present in almost all cases. Preexisting stones in the donor kidney have been reported once previously. The authors have observed 2 such cases, detected by routine sonography. In 1 case, stone migration into the ureter led to acute postoperative transplant failure; this complication has been reported previously.

Adult↗

Effects of AMI-25 on liver vessels and tumors on T1-weighted turbo-field-echo images: implications for tumor characterization.

This study was devoted to tumor differentiation in liver MR T1-weighted imaging with superparamagnetic iron oxide (SPIO). Twenty-one patients with 40 liver lesions were studied at 1.5 T. Before and at least 45 minutes after SPIO administration, turbo-field-echo (TFE) T1-weighted, TFE T1 x T2*-weighted (MXT), and fat-suppressed turbo-spin-echo T2-weighted images were acquired. A quantitative analysis was performed blindly. On TFE T1-weighted images, the signal enhancement was -33% +/- 12 for the liver, -24% +/- 2 for adenomas and focal nodular hyperplasia, +60% +/- 33 for the hemangiomas; metastases and cyst enhancement were not significant. After SPIO on TFE T1-weighted images, the hemangioma-to-liver signal ratio (149% +/- 18) was definitely higher than the mean metastasis-to-liver signal ratio (90% +/- 16). This T1-related differentiation ability lacked dramatically on TFE MXT images and, in one case, was reduced on post-SPIO TFE T1-weighted images by a long imaging delay after SPIO administration (2 hours).

Adult↗

Magnetic resonance angiography of intravascular endoprostheses: investigation of three devices.

PURPOSE: To assess the value of magnetic resonance angiography (MRA) in the evaluation of vascular patency after intravascular endoprosthesis placement. METHODS: Three different metallic stents (Wallstent, Strecker, Palmaz) were studied in vitro, and in vivo in six patients with spin-echo (SE) and gradient-echo (GRE) MR imaging. Time-of-flight, two-dimensional (2D) gadolinium-enhanced MRA was performed with GRE and flow-compensation technique, and reconstructed with a maximum-intensity projection (MIP) algorithm. MRA was compared to digital angiograms. RESULTS: In vitro studies demonstrated that the signal intensity (SI) within the stent differed according to the device employed, the lowest SI being observed within the Palmaz stent (p = .001). There was no difference in SI or apparent diameter of the stent according to the sequence (SE vs GRE) or length of echo time (TE). In patients, the endoprostheses recorded as a well-defined area of signal void or drop-out (p = 0.004), whereas vessels above and below the stent displayed high signal intensities. CONCLUSION: MRA does not seem as yet to be well suited for evaluating vascular patency after endoprosthesis placement, even if the Strecker and Wallstent endoprostheses provide fewer artifacts than the Palmaz stent.

Arterial Occlusive Diseases↗