Biomedical subjects

L Needleman

Publications and source records attributed to L Needleman.

At least 19 recordsLinked to original sources

PubMed2001

The role of preoperative radial artery ultrasound and digital plethysmography prior to coronary artery bypass grafting.

OBJECTIVE: Doppler ultrasound and digital plethysmography are used at our institution to determine the suitability of the radial artery for harvest prior to coronary artery bypass grafting (CABG). The purpose of this study is to determine the value of this preoperative evaluation. METHODS: A retrospective analysis of non-invasive radial artery testing was performed on 187 CABG patients. Criteria used to exclude radial arteries from harvest were anatomic abnormalities (size<2 mm, diffuse calcifications), and perfusion deficits during radial artery occlusion (>40% reduction in digital pressure, non-reversal of radial artery flow, or minimal increase in ulnar velocity). A questionnaire was used to determine the incidence of postoperative hand ischemia or rehabilitation. RESULTS: In 187 patients, 346 arms were evaluated. Ninety-four arms (27.1%) were excluded for harvesting. Anatomical abnormalities included size<2 mm (1.5%), diffuse calcifications (8.7%), congenital anomalies (2.3%), and radial artery occlusion (0.3%). Circulatory abnormalities included non-reversal of flow (7.2%), abnormal digital pressures (5.5%), and inappropriate increase in ulnar velocity (1.7%). A total of 116 radial arteries were harvested. There were no episodes of hand ischemia. No patient required hand rehabilitation. CONCLUSIONS Doppler ultrasound and digital plethysmography identifies both perfusion (14.5%) and anatomical (12.7%) abnormalities that may make the radial artery less suitable as a bypass conduit.

Collateral Circulation↗

PubMed2001

The role of contrast-enhanced sonography for radiofrequency ablation of liver tumors.

OBJECTIVE: To assess the feasibility and usefulness of contrast-enhanced sonography for tumor detection and guidance of liver VX2 tumor ablation and to evaluate post radiofrequency ablation effectiveness. METHODS: VX2 tumors were implanted into the livers of 6 rabbits. Both conventional and harmonic gray scale and power Doppler imaging were performed with a commercially available scanner to evaluate the liver tumors before and after intravenous injection of a sonographic contrast agent before and after radiofrequency ablation. Contrast-enhanced imaging was used to detect the tumors before ablation, to guide needle insertion, and to measure the ablation sites after radiofrequency ablation. Pathologic examination was performed for comparison. RESULTS: Three tumors were seen without contrast enhancement, whereas 10 tumors (<1 cm) were detected with contrast enhancement. Intentionally, 2 tumors were completely ablated and 5 tumors were partially ablated. In 3 cases, incompletely ablated tumors could only be identified on contrast-enhanced Doppler imaging by enhancing the detection of residual tumor vascularity. There was excellent concordance between sonographic imaging and gross pathologic findings. CONCLUSIONS: Contrast-enhanced sonographic imaging appears useful for detection of liver tumors and for guiding and monitoring tumor ablation therapies.

Animals↗

PubMed2001

Sonographically guided renal mass biopsy: indications and efficacy.

PURPOSE: To review the clinical indications, pathologic results, and success rate of all our sonographically guided solid renal mass biopsies over a 5-year period. METHODS: Between 1993 and 1998, 44 consecutive patients underwent sonographically guided percutaneous biopsy of a solid renal mass. Indications included prior history of nonrenal malignancy, metastatic disease of unknown primary origin, previous contralateral nephrectomy for a renal cell neoplasm, a renal transplant mass, suspected renal lymphoma, history of tuberous sclerosis, and poor surgical candidacy. Aspiration biopsies were initially performed with 22- to 18-gauge spinal needles. If the initial cytologic evaluation findings were nondiagnostic, core biopsies were then performed with 20- to 18-gauge core biopsy guns. Dictated sonographic reports of the biopsies were reviewed to determine the following: indication for biopsy, location and size of the renal mass, needle gauge and type, number of needle passes, and complications. Final cytologic and surgical pathologic records were reviewed. RESULTS: Thirty-six (82%) of the 44 biopsy specimens were diagnostic. Aspirated smears were diagnostic in 24 (67%) of these cases, with the diagnosis made on the basis of cell block alone in an additional 2 (6%). A definitive diagnosis came from core biopsy alone in 10 cases (28%). The 18-gauge core needle yielded diagnostic results more reliably than the 20-gauge core needle, and a significant correlation was seen between core biopsy needle size and the rate of diagnostic core samples (P = .017). Pathologic diagnoses included renal cell carcinoma (n = 18), lymphoma (n = 4), oncocytic neoplasm (n = 4), transitional cell carcinoma (n = 2), angiomyolipoma (n = 1), papillary cortical neoplasm (n = 1), and metastatic carcinoma (n = 6). Complications were seen in 4 (9%) of 44 cases; all were treated conservatively. CONCLUSIONS: For specific clinical indications, sonographically guided fine-needle aspiration and core biopsy of a solid renal mass can be performed safely. In many cases, a definitive diagnosis can be made on the basis of fine-needle aspiration alone. However, diagnosis may ultimately require core biopsy, for which 18-gauge core needles would be more reliably diagnostic than 20-gauge needles.

Adult↗

PubMed2001

Feasibility of performing a virtual patient examination using three-dimensional ultrasonographic data acquired at remote locations.

OBJECTIVE: To evaluate the feasibility of performing three-dimensional ultrasonographic studies that meet American Institute of Ultrasound in Medicine and American College of Radiology ultrasonographic examination guidelines with review off-line and at remote locations. METHODS: One hundred patients were studied at 2 institutions using high-end two-dimensional clinical ultrasonographic scanners and commercially available three-dimensional ultrasonography for a variety of organ systems (first- and second-trimester fetus, abdomen, and female pelvis). We evaluated several parameters, including measurements, completeness of organ visualization, abnormalities identified, image quality, number of volumes required, and discrepancies between interpretations. RESULTS: Overall, three-dimensional ultrasonography could produce diagnostic-quality results comparable with those of two-dimensional ultrasonography. Three-dimensional ultrasonographic image quality was lower than that of two-dimensional ultrasonography. Two- and three-dimensional ultrasonographic measurements were comparable (<5% difference), as was the extent of organ visualization, although some structures were challenging for both two- and three-dimensional ultrasonography. In general, organs completely imaged in the scanner field of view required 1 to 1.5 volumes, whereas larger organs required between 3 and 6 volumes. Differences among reviewers' interpretations highlighted the need for standardization of acquisition and reviewing protocols for sonographers and physicians. CONCLUSIONS: Our results show that it is clinically feasible to acquire three-dimensional ultrasonographic data at one site and to obtain accurate interpretation by off-line review at another within the context of providing high-quality clinical diagnostic studies.

Abdomen↗

PubMed2001

Intraoperative sonographic localization of breast masses: success with specimen sonography and surgical bed sonography to confirm excision.

OBJECTIVE: To assess the use of intraoperative sonography for localization of breast masses at excisional biopsy, with specimen and surgical bed sonography to confirm excision. METHODS: A computer search of the 5-year period from January 1993 through January 1998 revealed 138 consecutive women referred for sonographically guided excisional biopsy of 148 masses; 35 masses were excluded because they had no postoperative mammograms. One hundred thirteen masses constituted the study group. Specimen sonography (n = 60) or surgical bed sonography (n = 53) was performed as the initial evaluation to confirm excision, but ultimately, surgical bed sonography may have been necessary after specimen sonography, and specimen sonography may have been necessary after surgical bed sonography. The miss rates determined by postoperative imaging were calculated for each group and compared with those of mammographically guided needle localization series from the literature. RESULTS: Follow-up physical examination and mammography showed no residual mass in the region of surgery in any patient. However, follow-up sonography had 1 miss in the initial specimen sonogram group (1 [1.7%] of 60) and 1 miss in the initial surgical bed group (1 [1.9%] of 53). As shown by the Fisher exact test, there was no significant difference between the miss rates of the 2 initial methods of confirming lesion excision or between the miss rates of these initial methods, both groups combined, and 6 mammographic localization series from the literature. CONCLUSION: Intraoperative breast sonography, using specimen sonography and scanning the surgical bed, has miss rates comparable with those of mammographic needle localization. Follow-up sonography must be performed if there is any doubt of complete excision.

Adult↗

PubMed2000

Breast tumor vascularity identified by contrast enhanced ultrasound and pathology: initial results.

Quantifiable measures of vascularity obtained from contrast enhanced color flow images were correlated with pathologic vascularity measurements in ten female patients with a solid breast mass. Each patient received Levovist Injection (Berlex Laboratories Inc., Montville, NJ). Color flow images pre- and post-contrast were obtained using an HDI 3000 unit (ATL, Bothell, WA) before removing the mass for pathologic vascularity assessments. Image-processing techniques were used to obtain both the ultrasound and pathologic vascularity measurements. Multiple linear regression found significant correlations for ultrasonic vascularity measurements post contrast and pathology (P = 0.02 and 0.06). No correlations were found between pre-contrast ultrasound and pathology. In conclusion, post-contrast ultrasonic flow measures provide a non-invasive measure of breast tumor neovascularity. However, the patient population is small, and until further patients are analyzed, these conclusions are preliminary.

Breast Neoplasms↗

PubMed2000

Safety and efficacy of sonographically guided random core biopsy for diffuse liver disease.

Sonographic guidance is commonly used in the biopsy of focal hepatic lesions, but biopsy for diffuse disease is often non-image-guided. We evaluated the safety and efficacy of real-time sonographically guided random core biopsy in the assessment of diffuse liver disease in 210 patients. The two most common indications for biopsy were viral hepatitis (in 113 patients) and elevated liver function test results of unknown cause (in 54 patients). Ultrasonography and pathology reports were reviewed retrospectively to determine number of needle passes and final diagnoses. Adequate tissue was obtained in all 210 patients, with 259 of 269 (96%) passes having been successful. Specimens were submitted for light microscopy and other tests as indicated. No difference in success rates was found for right and left lobe biopsies. No major complications occurred. Minor complications occurred in 10 of 210 (4.8%) patients and were self-limited. Sonographically guided core liver biopsy is a safe and effective method for the diagnosis of liver disease.

Adult↗

PubMed2000

Shear rate estimation using a clinical ultrasound scanner.

Wall shear stress is a factor in the development of atherogenesis, thrombus formation, and embolization, but its existence is very difficult to determine with ultrasonography. Instead, we estimated shear rates using a clinical ultrasound scanner and compared results from vessels with and without stenoses. Velocity profiles were obtained from color M-mode images on a P700 scanner. Maximum shear rates were calculated off-line as the maximum velocity gradients. In vitro, studies were performed on a flow phantom with a vessel containing a 50% stenosis. Shear rates within the stenosis were significantly higher than those obtained outside the stenosis (P < 0.00001) and varied more than the peak velocities. In vivo, the internal carotid artery of 10 volunteers and 13 patients (with stenoses) was studied. The mean shear rate was 414 s(-1) +/- 154.5 s(-1) in normal vessels and 687 s(-1) +/- 263.5 s(-1) in stenotic vessels (P = 0.00017). In conclusion, shear rate estimates can be obtained with a clinical ultrasound scanner from color M-mode images. Shear rates estimated in vessels with stenoses are significantly higher than those obtained in normal vessels in vitro as well as in vivo.

Blood Flow Velocity↗

PubMed2000