Biomedical subjects

S H Duda

Publications and source records attributed to S H Duda.

114 records · Page 7Linked to original sources

PubMedDate not supplied

Superparamagnetic iron oxide: detection of focal liver lesions at high-field-strength MR imaging.

AMI-25 was evaluated at 1.5 T as a superparamagnetic iron oxide contrast agent for the liver. Sixteen patients with up to five suspected focal liver lesions were examined with T1-, proton-density-, and T2-weighted spin-echo sequences before and after intravenous administration of AMI-25 (15 mumol/kg iron). The contrast-to-noise ratio (C/N) increased from 1.8 to 3.5 on 600/15 (TR msec/TE msec) images and from 1.7 to 7.9 on 2,500/15 images after AMI-25 administration (P < .01). C/N did not change significantly on 2,500/90 images. Two blinded readers counted the number of lesions visible on unenhanced and contrast-enhanced images, with the 32 sets of images of the 16 patients presented in random order. Both readers identified more lesions on AMI-25-enhanced images, but the difference was not statistically significant (P > .05). Two patients reported minor side effects (flushing, sensation of heat, lower back pain). On the basis of the results obtained in a limited number of patients, the authors conclude that at 1.5 T, AMI-25 does not significantly improve the detection of focal liver lesions on conventional spin-echo images.

Contrast Media↗

PubMedDate not supplied

Ultrasound-monitored laser angioplasty: preliminary clinical results.

A novel coaxial catheter system for ultrasound (US)-guided, pulsed laser angioplasty was tested clinically in 4 patients with stenoses of the femoral and external iliac artery. The mean lesion length was 1.3 +/- 0.4 cm. The 9F multifiber laser catheter incorporated a 4.8F commercial intravascular US catheter and can be guided over a 0.014 inch wire. Laser angioplasty alone reduced the mean degree of stenoses from 84 +/- 8% to 47 +/- 10%. Though laser-induced artifacts compromised detailed US monitoring during laser firing itself, the system proved to be clinically useful as assessment of laser effects and measurement of the severity of residual stenoses was possible immediately after laser irradiation.

Aged↗

PubMedDate not supplied

Embolization of renal vascular lesions: clinical experience with microcoils and tracker catheters.

After biopsy (n = 6) and nephrostomy (n = 1) of three native and four transplanted kidneys, gross hematuria, hypertension, and deterioration of function necessitated performance of transarterial embolization. Angiography revealed five arteriovenous fistulas (AVFs), one pseudoaneurysm, and one arteriocaliceal fistula. Superselective catheterization was accomplished using 5 Fr standard diagnostic catheters and 3 Fr coaxial Tracker catheters. Four of five AVFs were embolized successfully by inserting unfibered (2 patients) and fibered (2 patients) platinum coils (diameters 2 mm and 4 mm, respectively). For one AVF, additional injection of butylcyanoacrylate was necessary. The pseudoaneurysm was embolized successfully by such injection, and the arteriocaliceal fistula was occluded using one unfibered 2-mm coil. Embolization stopped the bleeding in all patients. One week after treatment, renal function was improved in 5 patients and remained unaffected in 2. Superselective embolization using Tracker catheters and fibered microcoils is an effective, safe treatment of renal vascular lesions.

Adult↗

PubMedDate not supplied

Percutaneous transhepatic intraductal biliary sonography for lymph node staging at 12.5 MHz in malignant bile duct obstruction: work in progress.

PURPOSE: To assess the value of intraductal ultrasound (US) for lymph node staging in malignant biliary obstruction. METHODS: Eighteen patients with malignant extrahepatic obstruction were imaged during percutaneous bile duct drainage with a mechanically rotating US transducer at 12.5 MHz. Detectable lymph nodes were classified as malignant when two of three criteria (hypoechoic, rounded, conspicuous margins) were fulfilled. The results were compared with histopathological data in 8 patients and follow-up CT findings in 10 patients. RESULTS: In 15 of 18 patients (83%) malignant lymph node involvement was suspected at intraductal US and in 5 of 18 patients (28%) during CT. Histopathological investigation after operation (n = 8) and follow-up CT studies (n = 10) revealed the presence of malignant nodal involvement in 13 of 18 (72%) patients. The sensitivity, specificity, and accuracy of transhepatic intraductal biliary US in determining merely the presence or absence of malignant lymph nodes without specific topographic assignment were 92%, 40%, and 78%, respectively. CONCLUSION: These preliminary results suggest that intraductal US may develop into a promising adjunctive modality during percutaneous bile duct drainage in patients with suspected malignant regional lymph node involvement.

Adult↗

PubMedDate not supplied

Local administration of ramiprilat is less effective than oral ramipril in preventing restenosis after balloon angioplasty in an animal model.

PURPOSE: To test the hypothesis that local administration of angiotensin converting enzyme (ACE) inhibitor via a microporous balloon catheter would be more effective than oral administration of ACE inhibitor in preventing neointima formation after balloon angioplasty. MATERIALS AND METHODS: Neointima formation was induced by balloon denudation followed by 0.5% cholesterol diet in 29 New Zealand White rabbits. Directly after denudation, local administration of 1.8 mg of ramiprilat (n = 7) or saline (n = 7) with a microporous balloon catheter at a pressure of 3 atm was performed. Both groups additionally received ramipril orally (1 mg/d). Seven animals were treated exclusively with oral ramipril. The control group was fed a 0.5% cholesterol diet and given no medication (n = 8). Six weeks after intervention, the animals were killed and morphometric and immunohistologic analyses were performed. RESULTS: Oral administration of ramipril resulted in a significant reduction of placque area (-66%, P < .05). Oral and local administration of the ACE inhibitor was followed by a nonsignificant reduction of the neointimal area (-17%). Local administration of saline combined with oral ramipril failed to prevent neointimal formation (reduction of 6%, NS). CONCLUSION: Oral administration of ramipril resulted in a significant reduction of neointimal proliferation in New Zealand White rabbits. The possible benefit of an additional administration of local ramiprilat was diminished by an excessive neointimal hyperplasia, which was most likely caused by the inherent vessel trauma with use of the microporous balloon catheter.

Administration, Oral↗

PubMedDate not supplied

Lipids in bone tumors assessed by magnetic resonance: chemical shift imaging and proton spectroscopy in vivo.

The methods of fat and water selective magnetic resonance (MR) imaging and localized 1H MR spectroscopy were evaluated in the course of 37 examinations on 27 primary bone tumors. These methods are capable of demonstrating small amounts of lipids inside the tumors and subtle edema in the adacent bone marrow, in contrast to the usually applied spin-echo and gradient-echo sequences providing signals dependent on the total proton density and on the relaxation times. The tumor masses of the malignant tumors were free of signals in the fat selective images, whereas in three out of six osteochondroma fat signals could be detected. Localized MR spectroscopy was more sensitive even to very low lipid content (lipid portion < 0.5%) in the tumors and revealed signals with J-coupling from seven out of 13 malignant tumors.

Adolescent↗