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Biomedical subjects

L Arrive

Publications and source records attributed to L Arrive.

13 recordsLinked to original sources

Magnetic resonance imaging: a new tool in the diagnosis of tumours of the nail apparatus.

Tumours of the nail apparatus are often the subject of diagnostic dilemma. Until now, no reliable imaging methods have been available to assess these lesions correctly. We report the results of high and very high-resolution magnetic resonance imaging (MRI), which have been correlated with the anatomical findings in 14 cases of nail apparatus pathology, and discuss the possible contribution of MRI to diagnosis. With very high-resolution MRI, accurate analysis of the anatomy of the nail apparatus is possible, and lesions as small as 1 mm can be detected. An expansive process can be excluded when results are negative. Glomus tumour, mucoid pseudocyst, fibrokeratoma, and exostosis can be differentiated because of their different MRI characteristics. This is of importance when the exact nature of a subungual tumour cannot be determined by clinical findings alone. Measurement, determination of the exact localization of the tumour, and the study of its relationship to the other structures, can provide guidance for subsequent surgical procedures. MRI is reliable and accurate in the delineation of lesions, and provides a new tool for the investigation of pathology of the nail apparatus.

Adolescent↗

Hepatic tumors: detection and characterization at 1-T MR imaging enhanced with AMI-25.

PURPOSE: To evaluate the ability of magnetic resonance (MR) imaging enhanced with AMI-25 to depict and characterize hepatic tumors. MATERIALS AND METHODS: Sixty-four patients (41 men and 23 women, aged 24-65 years [mean, 55 years]) underwent 1-T MR imaging: 22 had metastatic disease; 10, hepatocellular carcinoma; seven, hemangioma; three, focal nodular hyperplasia; three, gallbladder adenocarcinoma; two, lymphoma; one, adenoma; and 16, no tumor. Pre- and postcontrast images (alone and in combination) were analyzed by three independent radiologists. Receiver operating characteristic curves were constructed to compare tumor characterization. RESULTS: Signal intensity was decreased in all benign tumors but not in malignant tumors. The number of tumors depicted (nonenhanced images, 657 tumors; enhanced, 753; and combined, 760) was not statistically different. Receiver operating characteristic curves did not show improved characterization with AMI-25. CONCLUSION: AMI-25 does not improve depiction of hepatic tumors. Although characterization of hepatic tumors was not improved with AMI-25, uptake of AMI-25 seems specific for hepatic tumors at MR imaging.

Carcinoma, Hepatocellular↗

Diagnosis and management of 17 consecutive patients with inflammatory abdominal aortic aneurysm.

This report reviews the authors' experience in diagnosing and managing 17 consecutive patients with inflammatory abdominal aortic aneurysm (AAA). Among 491 patients undergoing repair for AAA during a 10-year period, 17 (3%) had evidence of associated periaortic fibrosis, which was confirmed histologically. No patient had acute rupture, and two patients (12%) had chronic contained rupture. Ureteral obstruction was evident in seven patients. In 41% of the patients, available surgical correlation demonstrated that computed tomographic (CT) scan accurately delineated the extent of the disease. Sixteen patients underwent aneurysm resection. Ureteral obstruction was relieved by ureterolysis in three patients treated early in this series. In the last period of the study, well-documented hydronephrosis spontaneously subsided in two patients without special treatment. Of these 17 patients, 15 (88%) were early (30-day) survivors. There were two late deaths at 2 months and 5 years; 12 (71%) patients are still alive and free of symptoms up to 10 years after operation. On the basis of our study, we conclude the following: (1) precise preoperative diagnosis and detailed anatomic information are widely available with CT; (2) aneurysm resection is the treatment of choice because the risk of rupture still exists, and this procedure seems to reverse the inflammatory process; (3) good early and late results can be expected with proper surgical technique; and (4) routine follow-up with CT is recommended to document resolution or progression of the fibrotic process after aneurysm resection.

Aged↗

Rapid, contrast-enhanced, diuretic magnetic resonance imaging of unilateral partial ureteral obstruction. An experimental study in micropigs.

The value of rapid, contrast-enhanced, diuretic magnetic resonance (MR) imaging (using ferrioxamine B and furosemide) in demonstrating partial unilateral ureteral obstruction and the potential of such MR imaging in differentiating obstructive from nonobstructive hydronephrosis was assessed in six micropigs. MR imaging (0.35 Tesla, partial-flip technique with repetition time [TR] of 125 milliseconds, echo-delay time [TE] of 20 milliseconds, and flip angle of 70 degrees) was performed before, and at 5, 12, and 19 days after partial ureteral obstruction. Additionally, MR images were acquired 5, 12, and 19 days after release of obstruction. The diuretic was injected 10 minutes after the contrast medium. MR findings were correlated with results from nuclear scintigraphy (99mTc-DMSA uptake). MR images provided good morphologic detail from which renal size, parenchymal thickness, and degree of hydronephrosis could be determined. Contrast medium allowed assessment of cortical uptake and urinary excretion. The course of cortical signal enhancement best characterized the difference between obstructive and nonobstructive hydronephrosis. Normal kidneys and kidneys with nonobstructive hydronephrosis showed progressive decrease in cortical signal enhancement (-11.7% within 40 minutes) after furosemide injection. The kidneys with obstructive hydronephrosis demonstrated a plateau of signal enhancement without decrease (-0.7% within 40 minutes). These results demonstrate the utility of rapid contrast-enhancing, diuretic MR imaging in differentiating obstructive from nonobstructive hydronephrosis.

Animals↗

Gynecologic tumor imaging.

Anatomy of the female pelvis is superbly delineated by MRI due to excellent soft tissue contrast. In patients with infertility, MRI is the best technique to evaluate suspected myomata. Since tumors are directly visualized, MRI can be an effective technique for staging cervical, uterine, and vaginal malignancies.

Female↗

MR staging of bladder carcinoma: correlation with pathologic findings.

Forty patients with bladder carcinoma were examined preoperatively by means of magnetic resonance (MR) imaging. In all patients, total cystectomy with enterocystoplasty and pelvic node dissection was performed. The surgical and pathologic findings were correlated with the MR findings. Extension through the deep muscle of the bladder wall was present in 20 of the 40 patients and was diagnosed with a sensitivity of 95% and a specificity of 95%. Extension to perivesical fat was present in 18 of 40 patients and was diagnosed with a sensitivity of 66% and a specificity of 100%. Invasion of the adjacent organs was present in nine of 40 patients and was diagnosed with a sensitivity of 44% and a specificity of 96%. On the basis of the MR findings, the tumor was correctly staged, according to the TNM classification, in 24 of 40 (60%) patients, tumor extension was overestimated in three of 40 (7.5%) patients, and tumor extension was underestimated in 13 of 40 (32.5%) patients. MR imaging has been shown to be accurate in identification of macroscopic lymph node involvement and deep muscle involvement. It appears to be at least as useful as computed tomography (CT) in the evaluation of perivesical fat involvement and to be superior to CT in the detection of invasion of adjacent organs. One limitation of MR imaging is in the evaluation of tumor extension into the periurethral glands.

Adenocarcinoma↗

[Results of abdominal x-ray computed tomography in 25 patients with the acquired immunodeficiency syndrome or the lymphadenopathy syndrome].

An abdominal computed tomographic examination was performed to 20 patients with Acquired Immunodeficiency Syndrome (AIDS) and to 5 patients with Lymphadenopathy Syndrome (LAS). Intraabdominal lymph nodes were seen in 18 out of 20 cases of AIDS and in 5 cases of LAS. Lymph nodes have a normal size or are slightly enlarged but they are too numerous. Splenomegaly was found in 17 patients. Rectal modifications secondary to a proctitis were seen in the homosexual patients.

Acquired Immunodeficiency Syndrome↗

MRI of the pelvis in comparison with CT scan.

This study gives results of magnetic resonance imaging (MRI) in the evaluation of male (23 cases) and female (29 cases) pelvis. Thirty nine patients with abnormal pelvis were compared with CT and ultrasounds. MRI and CT have proven equally sensitive to the presence of disease, with a better visualization of calcified tumours or benign lesions with CT, and a superior display of soft tissue spreads and bone metastases with MRI. The signal characteristics from various uterine, bladder and ovarian tumours show an overlap. The same phenomenon is observed between benign and malignant prostatic hypertrophy. The best sequences for pelvic study are, in our experience, IR or short TR spin-echo for T1-weighted images, and spin-echo with 1200 TR for T2 images. Calculated T1 and T2 maps may improve MRI results.

Adult↗

[Morphological diagnosis of pseudocystic tumors of the liver].

Ten cases of pseudocystic hepatic tumors were observed during the past ten years. This entity is very rare in comparison with benign hepatic cysts. Careful analysis of the characteristics of these lesions usually allows to differentiate them from benign cysts. Of importance are wall thickness, mural nodules and fluid/fluid levels on ultrasound and/or computed tomography scanning. In our series, sonography depicted the true morphology of these cystic masses more clearly than computed tomography. If definitive diagnosis cannot be made by morphologic examinations, percutaneous aspiration of the cystic lesion, a simple and safe method, should be considered.

Angiography↗