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Biomedical subjects

B Sigel

Publications and source records attributed to B Sigel.

At least 91 records · Page 5Linked to original sources
PubMed1983

The application of real-time ultrasound imaging during surgical procedures.

Operative ultrasound using real-time high resolution B-mode ultrasound scanning is a practical and useful diagnostic aid. At operations upon the biliary tract, pancreas and blood vessels, ultrasound had a favorable impact upon surgical management. When similar operative roentgenographic studies were available, operative ultrasound compared favorably with both operative cholangiography and arteriography. Problems with the lack of familiarity of the surgeon with the performance and interpretation of imaging ultrasound and lack of specifically dedicated ultrasound instruments need to be resolved to increase and improve the use of this potentially helpful aid to surgical diagnosis during operation.

Angiography↗
PubMed1982

Variable ultrasound echogenicity in flowing blood.

Real-time ultrasound imaging of large abdominal veins revealed bloodstream echogenicity of variable intensity. This variability is largely due to the entrance and persistance of tributary blood currents that show different echogenicity. Red cell aggregation is probably an important cause of bloodstream echoes and their variable intensity.

Animals↗
PubMed1982

Ultrasonic assistance during surgery for pancreatic inflammatory disease.

Real-time B-mode ultrasound scanning was used during 35 operations for inflammatory disease of the pancreas. In 21, ultrasonography was considered helpful in operative management of pancreatic pseudocysts, abscesses, and chronic pancreatitis. Assistance consisted of establishing a diagnosis not made during preoperative testing, more precisely localizing pancreatic abnormalities, and excluding the presence of pseudocyst, abscess cavities, and dilated ducts. Operative ultrasound is a safe and simple technique that may reduce the use of tissue dissection, contrast material injections, and radiation.

Abscess↗
PubMed1982

Ultrasonic imaging during vascular surgery.

Real-time B-mode ultrasound scanning was used during arterial reconstruction surgery to supplement the information of preoperative arteriography and to detect vascular defects immediately after restoration of blood flow. At 55 operations, 100 sites were examined. At three operations, ultrasound provided new information that, in two patients, directly affected the choice of operation. Intraoperative postreconstruction scanning detected vascular defects in over 20% of the patients. Intimal flaps were the commonest defects observed. In most instances in which defects were seen, the vessels were not reentered because the defects were considered to be too small or located in a nonstrategic site or both. One relatively large intimal flap in a common carotid artery prompted reentry. Ultrasound during vascular operations proved to be a highly sensitive diagnostic tool to supplement preoperative arteriography and to detect vascular defects resulting from reconstructive surgery.

Adult↗
PubMed1982

Detection of pancreatic tumors by ultrasound during surgery.

Real-time B-mode ultrasonic scanning was performed during 14 operations for pancreatic tumors. All operations were for adenocarcinoma, except in one patient with a Zollinger-Ellison tumor. The ultrasonic tissue appearance of pancreatic carcinoma was not specific. However, ultrasonic signs of pancreatic duct dilation, striction or invasion of the superior mesenteric veins, and common bile duct involvement may help to establish the diagnosis of malignancy. A triad of ultrasound signs indicative of malignant obstruction of the common bile duct consisted of (1) dilation, (2) absence of biliary stones, and (3) a distinctive termination pattern of the duct. Operative ultrasound was used to guide a biopsy needle to obtain pancreatic tissue samples. The Zollinger-Ellison tumor of the pancreas produced a sonolucent appearance that clearly distinguished it from the surrounding tissue.

Adenocarcinoma↗
PubMed1982

B-mode sonography of blood clots.

Systematic evaluation of blood clot echogenicity was performed with five different transducer frequencies in two experiments. In the first experiment, blood clots were insonified at five different time periods; from immediately after clotting up to 96 hours after clotting. In the second experiment, blood clots of four different hematocrits (48 to 20%) and clots of hemolysed blood were insonified. The clots, with normal hematocrits, were highly echogenic when imaged with 5, 7.5 and 10-MHz transducers immediately and 24 hours after clotting. The echo intensity decreased over the following days until it almost disappeared at 96 hours after clotting. Clot echogenicity was not observed with 2.25 and 3.5-MHz transducers, except at the interface between retracted clot and serum. Clot echogenicity decreased in proportion with the hematocrit. Hemolysed blood clots were not echogenic. It is concluded from this study that fresh blood clots are echogenic soon after thrombosis with high resolution imaging and this echogenicity diminishes with time. Ultimately with organization and lamination, echogenicity will recur.

Blood Coagulation↗
PubMed1982

Ultrasonic scanning during operation for renal calculi.

Real-time B-mode ultrasound scanning was used during operations for nephrolithiasis. Scanning was done before pyelotomy or nephrotomy to confirm the presence of calculi. For stones in an intrarenal position, requiring an incision through renal parenchyma for extraction, ultrasound permitted guidance for an exploratory needle to localize the calculi precisely. Once the needle tip was in the proximity of the stone a nephrotomy incision was made along the needle track. This procedure enabled the use of relatively small nephrotomy incisions and reduced search time and tissue manipulation. After calculi were extracted ultrasonography was used to make certain that all stone fragments were removed. Ultrasound was considered helpful in 15 of 16 operations.

Adult↗
PubMed1982

Detection of vascular defects during operation by imaging ultrasound.

Real-time high resolution ultrasound imaging was employed during reconstructive vascular operation in 165 patients. The purpose of this diagnostic procedure was to detect unrecognized strictures, thrombi, and intimal flaps in order to permit their surgical correction at the primary operation. Defects were discovered in 48 patients (29%). In 34 patients (21%), because of size and location, defects were not considered sufficiently significant to warrant re-exploration. In 14 patients (8%), ultrasound revealed defects that prompted immediate re-exploration. Patients with ultrasound defects considered to be insignificant did as well as patients with no demonstrable defects. In the 14 patients who were re-explored, 12 had major defects that were corrected. These 12 patients also did well after operation. In two of the 14 patients, defects could not be found at re-exploration. Both these patients experienced early thrombosis of bypass grafts. In 56 patients, ultrasound was compared with arteriography at the same operation. The accuracy of operative ultrasound and operative arteriography was 96% and 85%, respectively. Operative ultrasound is more accurate, simpler and safer than arteriography and may be the preferred method for detection of vascular defects at reconstructive surgery.

Humans↗
PubMed1982

Comparison of B-mode real-time ultrasound scanning with arteriography in detecting vascular defects during surgery.

Real-time B-mode ultrasonography was compared with arteriography to determine its usefulness in detecting vascular defects immediately after lower extremity bypass graft reconstruction. Both procedures were employed in 40 patients to locate strictures, thrombi, and intimal flaps. Defects were discovered in 12 patients. Four of these defects were considered clinically insignificant and not worth the risk of reentry; of the remaining eight patients in whom significant defects were seen on ultrasonography, arteriography, or both, seven were reexplored. The accuracy of ultrasonography and arteriography was 94.4% and 83.3%, respectively. It is concluded that ultrasonography is comparable with arteriography in the detection of vascular defects during surgery.

Angiography↗
PubMed1982

Arteriographic and ultrasonic evaluation of vascular clamp injuries using an in vitro human experimental model.

A new experimental model was developed for dynamic in vitro evaluation of clamp effects in normal and atherosclerotic human arteries. Five normal and 25 atherosclerotic arteries obtained at autopsy were perfused by a pulsatile blood pump. Five vascular clamps--DeBakey, Satinsky, Fogarty, bulldog and Potts--were applied separately to 150 arterial segments, 30 each. The arterial segments were examined by single exposure arteriography and real time ultrasonography. The arteries were opened longitudinally and examined for traumatic lesions and atherosclerotic plaques. Except for a single intimal tear, there were no lesions produced by the clamps applied to normal arteries. In atherosclerotic arteries, the number of traumatic lesions, intimal tears and flaps, was comparable for all five clamps except the bulldog clamp which caused no intimal flaps. Intimal tears and flaps were observed in 14 and 26 per cent of all atherosclerotic vessels, respectively. The occurrence of clamp trauma in atherosclerotic arteries was independent of the age, sex and direct clamp application to plaques. Sensitivity of intimal tears by arteriography and ultrasonography was comparable low. Intimal flap sensitivity and accuracy of ultrasonography were greater than that of arteriography, p less than 0.01. It is concluded that the occurrence of important trauma by vascular clamps in atherosclerotic arteries is high and occurs whether or not discrete plaques are clamped. Clamp trauma is minimal in normal arteries. Imaging ultrasonography is superior to arteriography in detecting intimal flaps and can demonstrate the majority of intimal flaps produced by vascular clamps.

Adolescent↗
PubMed1981

Identification of a parathyroid adenoma by operative ultrasonography.

During surgery, real-time ultrasound scanning accurately localized a parathyroid adenoma posterior to be the superior pole of the right thyroid lobe. This was made feasible because of the ultrasound features of parathyroid tissue and current developments in ultrasound instrumentation.

Adenoma↗
PubMed1981

Ultrasonic imaging during biliary and pancreatic surgery.

Real-time ultrasound scanning was used during operations on the biliary tract and pancreas. The principal application in biliary surgery was to evaluate the common bile duct for presence of calculi. Our initial experience indicates that operative ultrasonography compares favorably with operative cholangiography. In pancreatic operations, ultrasound has been helpful in the management of pseudocysts and chronic pancreatitis. For pseudocysts, ultrasonography has indicated cyst wall thickness and the presence of adjacent anatomic structures. Ultrasound has distinguished the fluid loculations of the pseudocyst from swelling due to inflammatory edema. In surgery for chronic pancreatitis, ultrasonography has revealed the size and location of pancreatic ducts. This information has been useful in helping select sites for internal drainage of pseudocysts and in chronic pancreatitis with ductal dilatation. Operative ultrasonography is a relatively simple procedure which has the potential for providing the surgeon with early information and decreasing the need for dissection and radiographic imaging.

Biliary Tract Diseases↗