Biomedical subjects

M Knelson

Publications and source records attributed to M Knelson.

6 recordsLinked to original sources

PubMed1995

Significance of percutaneous needle biopsy in patients with multiple pulmonary nodules and a single known primary malignancy.

OBJECTIVE: To determine the necessity of percutaneous lung biopsy in patients with a single known primary malignancy and multiple pulmonary nodules. DESIGN: Retrospective study. SETTING: Tertiary care university hospital. RESULTS: We reviewed all percutaneous lung biopsy specimens over a 6-year period. One hundred forty-six patients with a single known primary malignancy and multiple pulmonary nodules had biopsies performed up to 19 years following diagnosis of the primary neoplasm. One hundred thirty-seven biopsy specimens (93.8%) were positive for metastases. Eight patients (5.5%) had a nondiagnostic biopsy specimen; however, subsequent imaging studies and the clinical course strongly suggested diffuse metastatic disease. One patient (< 1%) with breast carcinoma developed nodules 3 years after initial diagnosis and had resolution without a definitive diagnosis or therapy. CONCLUSION: Patients with a single known primary malignancy and multiple pulmonary nodules who present for percutaneous needle biopsy will have pulmonary metastases in the vast majority of cases. Biopsy in these patients rarely changes the clinical course as other diagnoses are rarely established.

Adolescent↗

PubMed1994

Correction of central venous stenoses: use of angioplasty and vascular Wallstents.

Central venous stenoses are a frequent complication in hemodialysis patients. These lesions lead to fistula thromboses, arm swelling, and limit future vascular access. Stenoses are characterized by excellent initial response to transluminal angioplasty but rapid recurrence. Response to angioplasty allows classification of stenoses as elastic or nonelastic. The success of angioplasty alone in 30 patients with central venous stenoses was compared to angioplasty and Wallstent placement in 11 patients with recurrent stenoses. In those who had angioplasty alone, 7%+ failed angioplasty, 70% had > or = 50% improvement in the luminal diameter while 23% showed no improvement due to elastic lesions. Subsequently, 81% of those with a successful result restenosed at an average of 7.6 months while 100% of elastic lesions occluded in an average of 2.9 months. In the 10 patients who underwent angioplasty and Wallstent placement, 5 were due to elastic lesions with four recurrences at a mean of 8.6 months. Four of five patients (80%) stented with nonelastic lesions had reappearance of symptoms at a mean of 4.2 months. We conclude that vascular stents should be reserved for those lesions that show elastic recoil after standard angioplasty.

Aged↗

PubMed1993

Renal magnetic resonance angiography in the preoperative detection of supernumerary renal arteries in potential kidney donors.

RATIONALE AND OBJECTIVES: Careful evaluation of the renovascular anatomy in potential living-related kidney donors is essential regarding the presence of accessory renal arteries. Conventional arteriography remains the standard of evidence for delineating the renal arterial supply. We assessed the utility of two-dimensional phase contrast (PC) magnetic resonance angiography (MRA) in the workup of potential living-related renal donors. METHODS: Thirty-nine patients were examined with conventional arteriography and MRA, which was performed on a 1.5-T system using a two-dimensional PC technique in both coronal and axial planes (repetition time[TR]/echo time [TE] = 39/8.5 msec; flip 60 degrees; matrix 256 x 128; field of view, 28 cm2; 2 excitations; first-order gradient-moment nulling; 7-mm section with 2-mm overlap). The number of hilar and polar supernumerary renal arteries was determined. Hilar supernumerary arteries were classified as co-dominant if they were similar in size to the ipsilateral main renal artery. RESULTS: Conventional arteriography identified 78 dominant and 13 supernumerary (3 co-dominant, 10 accessory) renal arteries. Magnetic resonance angiography identified the proximal 35 mm of all 78 dominant and the 3 co-dominant renal arteries. Of the remaining ten (7 polar and 3 hilar) accessory vessels, only four were correctly identified with MRA. CONCLUSION: The high error rate (60%) suggests that two-dimensional PC MRA, as implemented, should not be used in the preoperative evaluation of potential renal donors.

Adult↗

PubMed1992

Renal revascularization: indications and results.

Although the prevalence of renovascular hypertension is low, clinical criteria can select a population in which renovascular hypertension is significantly more common (prevalence of 15%). In these selected patients, it is appropriate to proceed to a screening modality to look for a significant renal artery stenosis. Choices of the noninvasive methods include captopril-enhanced renal scintigraphy, magnetic resonance (MR) angiography, and intravenous digital subtraction renal angiography (DSRA). Intraarterial DSRA or conventional arteriography may also be used to reliably detect renal artery stenosis, with the advantage that both the diagnostic and the interventional procedure can be performed at the same setting. A high percentage of a group of patients who are selected by means of clinical and arteriographic studies will benefit from revascularization. Thus, the renal artery angioplasty may be performed during the arteriogram in which the stenosis is confirmed.

Adult↗

PubMed1989

Computed tomography-guided retroperitoneal biopsies.

A retrospective review was performed on consecutive patients who had a computed tomographic (CT) biopsy of the retroperitoneum at University Hospitals of Cleveland. Biopsies were performed using a 20-gauge Chiba needle (University Medical Instruments Corp, Ballston Spa, NY) and a 14-gauge Tru-Cut needle (Baxter Pharmaseal, Valencia, CA). The results included success rate, failure, and complications, and were determined by a review of patient charts, surgical results, and autopsy results. The 20-gauge needle aspirations were accurate in suggesting the diagnosis in 20 of 22 cases of metastatic disease and ten of 15 cases of lymphoma. Using the 20-gauge needle, it was not possible to make a specific diagnosis in any of the lymphoma patients or for unusual benign disorders. With the 14-gauge Tru-Cut needle, the correct diagnosis was made in 13 of 13 cases of metastatic disease, ten of 11 cases of lymphoma, and two of 2 cases of unusual benign disorders. It was also possible to make the specific diagnosis of the lymphoma type in ten of 11 cases. The only complication was a small subcutaneous hematoma following a biopsy with a 20-gauge Chiba needle.

Biopsy, Needle↗

PubMedDate not supplied

The response of the portal vein to an oral glucose load.

Changes of total blood flow, velocities, and cross-sectional area in the portal vein before and after oral glucose administration were studied using image-directed Doppler ultrasonography. Portal vein cross-sectional area, flow velocity, and total blood flow increased significantly compared with baseline studies. Relative increase in these values compared with baseline studies (95% confidence intervals) are presented, and future applications of this method are discussed.

Administration, Oral↗