Biomedical subjects
Publications and source records attributed to J Machi.
Real-time ultrasound B-mode scanning was used during vascular operations to detect defects produced by reconstructive surgery. Ultrasound detection of defects was more accurate than arteriography. Use of operative imaging led to re-exploration and correction of defects in 8% of patients undergoing vascular reconstruction.
Operative ultrasonography and operative radiographic cholangiography were compared for diagnostic effectiveness with regard to their ability to screen the common bile duct for the presence of calculi. We performed real-time B-mode ultrasonography and cholangiography using two injections of contrast material. In 350 patients, 349 ultrasonic and 285 cholangiographic examinations were performed with technically satisfactory results. The sensitivity, specificity, efficiency, and predictability of a negative test were at a high and comparable level for the two diagnostic procedures. However, the predictability of a positive test for ultrasonography of 91.8% was significantly greater (P less than 0.02) than the predictability of 73.2% for cholangiography. Since predictability of a positive test is based on common duct exploration rather than presumptive evidence of a clinical course, this test may be more valid than the other measures to determine diagnostic effectiveness. The advantages of ultrasonography, which are superior accuracy, favorable image qualities, reduced invasiveness, increased safety, avoidance of contrast material, and lower cost, were contrasted with the problems of ultrasonography, which included a slow learning curve for performance and interpretation of the technique and the limited availability of dedicated ultrasound equipment for surgical operations. We concluded that the advantages outweighed the problems and that operative ultrasonography of the common duct warrants wider application in clinical surgery.
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.
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.
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.
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.
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.
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.
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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.
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Real-time ultrasonography can detect the movement of viscera immediately deep to the abdominal wall. This motion of abdominal contents is called viscera slide, and is produced by the force of respiratory motion (spontaneous viscera slide) or by manual ballottement of the abdomen (induced viscera slide). Viscera slide was observed in 18 "normal" subjects (no history of previous abdominal surgery or peritonitis) and in 24 subjects at "risk" for abdominal wall adhesions because of previous abdominal operations or past history of peritonitis. In 14 of the 24 "risk" group subjects, spontaneous and induced viscera slide was restricted to excursions of less than 1 cm (58.3%). Operations were performed on 18 patients, which confirmed the fact that restriction of ultrasonically detected viscera slide identified abdominal wall adhesions in all cases, but no adhesions were found in patients with normal viscera slide. This ultrasonic finding of restricted viscera slide may be useful in the preoperative discovery and localization of abdominal wall adhesions prior to laparoscopy or laparotomy.
Intracorporeal ultrasonography was used as a new method to examine the bile ducts during laparoscopic cholecystectomy. A prototype rigid 7.5-MHz ultrasound probe, 10 mm in diameter and 50 cm in length, was introduced during 25 laparoscopic cholecystectomies. A dual scanning technique was developed for complete examination of the bile duct. This entailed transverse scanning via the subxyphoid trocar and longitudinal scanning via the umbilical trocar. The intrahepatic ducts were also visualized by placing the probe on the liver surface. Color Doppler imaging was useful to quickly distinguish the duct from vascular structures. Laparoscopic ultrasonography clearly delineated the bile ducts in all operations except one. The time required for imaging was significantly shorter for ultrasonography than for cholangiography. Our preliminary experience demonstrates that a complete examination of the bile ducts can be performed with intracorporeal ultrasonography in a relatively short period of time.
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On the basis of our experience with operative ultrasonography during hepatobiliary and pancreatic surgery, its indications, benefits, and disadvantages are summarized. High-resolution operative ultrasound scanning of the liver, biliary tract, and pancreas was performed during 357, 735, and 242 operations, respectively. The benefits of operative ultrasonography were categorized as acquisition of diagnostic information otherwise not available, replacement for or complement to operative radiography, and guidance of surgical procedures. Operative ultrasonography provided beneficial information during 73 of 82 hepatic operations (89.0%), 57 of 69 noncalculous biliary operations (82.6%), and 177 of 242 pancreatic operations (73.1%). Operative ultrasonography was significantly superior (sensitivity 93.3%) to other screening tests for diagnosing liver metastasis from colorectal carcinoma evaluated in 189 patients, and it detected previously unrecognized metastatic tumors in 18 patients (9.5%). For screening common bile duct calculi during 666 operations, operative ultrasonography and operative cholangiography were comparable in all indices of accuracy except for a higher predictability of a positive test of operative ultrasonography (94.8% versus 71.7%). For diagnosing portal vein invasion of pancreatic carcinoma, operative ultrasonography provided better overall accuracy than preoperative studies (89.7% versus 64.1%). On the basis of operative ultrasound findings, previously planned surgical procedures were altered in 32 of 82 hepatic operations (39.0%) and 24 of 145 pancreatic operations for chronic pancreatitis (16.6%). Operative ultrasound guidance of various surgical procedures was performed during 88 hepatic and 84 pancreatic operations, including 40 ultrasound-guided hepatectomies and 42 pancreatotomies. Operative ultrasonography has a number of advantages, such as safety and speed in performance, wide application, high diagnostic accuracy, and ability of guiding procedures. Its disadvantages are the limitation of the fields of view in certain applications, the need for special equipment, and a slow learning curve.
The accuracy of intraoperative ultrasonography in diagnosing liver metastasis was evaluated at the time of surgery and at follow-up in 189 patients with colorectal cancers. Evaluation at the time of operation revealed that the sensitivity of intraoperative ultrasonography (93.3%) was significantly (p less than 0.0001) higher than that of preoperative ultrasonography (41.3%), conventional computed tomography (47.1%), and surgical exploration (66.3%). Twenty-two of 104 metastatic liver tumors were detected solely by intraoperative ultrasonography in 18 patients (9.5% of total patients). These 22 tumors were small in size (4 x 4 mm to 15 x 18 mm) and nonpalpable during operation. During the postoperative follow-up period of 18 months or more (mean 35.6 months, median 37.1 months) after colorectal surgery, liver metastases that were unrecognized during surgery appeared in 13 (6.9%) patients. Re-evaluation based on these follow-up results indicated that the sensitivity of intraoperative ultrasonography decreased to 82.3%, which was still significantly (p less than 0.0005) better than that of other methods. Intraoperative ultrasonography was capable of identifying 18 of 31 (58.1%) patients in whom liver metastases were otherwise unrecognized at the time of operation. Intraoperative ultrasonography is more accurate in diagnosing liver metastasis than traditional screening methods, and may have a beneficial impact on the management of colorectal cancer.
Only 10% to 20% of patients with primary and colorectal metastatic liver tumors are candidates for curative surgical resection. Even after curative treatment, tumors recur commonly in the liver. As a less invasive therapy, radiofrequency thermal ablation (RFA) of primary, metastatic, and recurrent liver tumors was performed under percutaneous, laparoscopic, or open intraoperative ultrasound guidance. The safety and local control efficacy of RFA were investigated. RFA was performed mostly in patients with unresectable hepatomas or metastatic liver tumors. Patients with large tumors, major vessel or bile duct invasion, limited extrahepatic metastases, or liver dysfunction were not excluded. An RFA system with a 15-gauge electrode-cannula with four-pronged retractable needles was used. All patients were followed for more than 8 months to assess morbidity and mortality, and to determine tumor recurrence. Sixty RFA operations were performed in 46 patients: 11 patients underwent repeat RFA once or twice. A total of 204 tumors were treated: 70 hepatomas and 134 metastatic tumors. Tumor size ranged from 5 mm to 180 mm (mean 36 mm). RFA was performed in 29 operations for 81 tumors percutaneously, in seven operations for 14 tumors laparoscopically, and in 24 operations for 109 tumors by open surgery. Combined colorectal resection was carried out in five operations and combined hepatic resection was carried out in three operations. There was one death (1.7%) from liver failure, and there were three major complications (5%): one case of bile leakage and two biliary strictures due to thermal injury. There were no intra-abdominal infectious or bleeding complications. The length of hospital stay ranged from 0 to 2, 1 to 3, and 4 to 7 days for percutaneous, laparoscopic, and open surgical RFA, respectively. During a mean follow-up period of 20.5 months, local tumor recurrence at the RFA site was diagnosed in 18 (8.8%) of 204 tumors. The risk factors for local recurrence included large tumor size and major vessel invasion: recurrence rates for tumors less than 4 cm, 4 to 10 cm, and greater than 10 cm, and for those with vessel invasion were 3.3%, 14.7%, 50%, and 47.8%, respectively. Ten of 18 tumors recurring locally were retreated by RFA, and eight of them showed no further recurrence. Ultrasound-guided RFA is a relatively safe, well-tolerated, and versatile treatment option that offers excellent local control of primary and metastatic liver tumors. The appropriate use of percutaneous, laparoscopic, and open surgical RFA is beneficial in the management of patients with liver tumors in a variety of situations.
High-resolution ultrasonic imaging of circulating blood was used to study the relation between red cell aggregation and blood clotting in vitro. A reversible increase in echogenicity produced by red cell aggregation occurred in moving heparinized blood as shear rate was decreased. We induced clotting of the heparinized blood by administration of protamine. At both low (1.6 sec-1) and moderate (22.6 sec-1) mean shear rates, transient homogenous increased echogenicity indicative of red cell aggregation preceded blood clotting. In separate experiments, we established that protamine can cause increased echogenicity due to red cell aggregation which can be reversed by adding heparin to circulating suspended red cells in the absence of clotting factors. Presumably, these effects of protamine and heparin are due to electrostatic bonding involving red cell surfaces. We conclude from these studies that red cell aggregation precedes clotting of heparinized blood by protamine at low and moderate shear rates.