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Biomedical subjects

R H Hawes

Publications and source records attributed to R H Hawes.

At least 55 records · Page 3Linked to original sources
PubMed2000

A multispecialty approach to the diagnosis and management of pancreatic cancer.

This article reviews recent developments in pancreatic cancer research and offers a multispecialty perspective on the diagnosis and management of this challenging disease. Current findings in the molecular biology of the disease and their implications for management are examined, as well as development in diagnostic techniques, including helical computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangio-pancreatography (MRCP), and, particularly, endoscopic ultrasound-guided fine-needle aspiration. Surgical management, the role of adjuvant/neoadjuvant chemoradiation therapy, and the critical importance of accurate preoperative imaging are also addressed in this review. Palliative techniques, including endoscopic stenting for malignant obstructive jaundice and chemotherapy for locally advanced and metastatic disease, are discussed, and results of recent clinical trials in pancreatic cancer are summarized. Finally, future directions for research are identified.

Humans↗
PubMed2000

Endoscopic ultrasound.

Endoscopic ultrasound was introduced in the early 1980s. Today, endoscopic ultrasound remains the most accurate modality for local staging of gastrointestinal cancers but the emphasis is now on what findings will impact patient care. At the same time, a new era of interventional endoscopic ultrasound that might also be called image-directed therapies is emerging. The future looks bright for the further application of endoscopic ultrasound in gastrointestinal endoscopy. This article provides the current status and a glimpse into the future of endoscopic ultrasound.

Digestive System↗
PubMed2000

Remote clinical assessment of gastrointestinal endoscopy (tele-endoscopy): an initial experience.

BACKGROUND: Gastrointestinal (GI) endoscopy is an effective tool to screen for cancers of the digestive tract. However, access to endoscopy is limited in many parts of South Carolina. This trial is a part of a prospective multi-part study for remote cancer screening in coastal South Carolina. This pilot study was to evaluate the quality of tele-endoscopy for cancer screening. METHODS: 10 patients scheduled for endoscopic procedures were observed simultaneously by the endoscopist and a remote observer connected over a 512 kbps ISDN line. Findings by both were compared for concordance on malignant or premalignant lesions. RESULTS: The image quality was adequate to support remote diagnosis of GI cancer and abnormal lesions by an experienced observer. However, assessment of the esophagogastric junction for Barrett's esophagus was equivocal. CONCLUSIONS: Overall, our tele-endoscopy setup shows great promise for remote supervision or observation of endoscopic procedures done by nurse endoscopists. Tele-endoscopy is both adequate and feasible for diagnosis of most gastrointestinal lesions. Subtle lesions still may be missed in our current setup. However, improvements are being made in our setup to address the problem with resolution prior to further evaluation.

Endoscopes, Gastrointestinal↗
PubMed1999

Esophageal cancer staging: improved accuracy by endoscopic ultrasound of celiac lymph nodes.

BACKGROUND: Clinical staging of esophageal cancer is required for optimal therapy but remains imprecise. Pathologic verification of involved lymph nodes could potentially direct treatment allocation. With the rising incidence of distal and gastroesophageal junction adenocarcinomas, assessment of the celiac axis lymph nodes (CLNs) becomes important because it is a common nodal drainage basin. Endoscopic ultrasound (EUS) permits evaluation of CLNs and biopsy by fine-needle aspiration. This study examined the usefulness of this staging tool. METHODS: A consecutive series of 62 patients with esophageal cancer considered resectable by computed tomographic scan underwent EUS for T and N staging and were retrospectively studied. A CLN visualized by EUS as greater than 5 mm was considered positive. Fine-needle aspiration of the CLN was performed routinely. Endoscopic ultrasound and computed tomographic staging were compared on the basis of pathologic verification of CLNs. RESULTS: It was possible to evaluate CLNs by EUS in 59 (95%) of 62 patients: positive in 19, negative in 40. In EUS-positive patients, fine-needle aspiration was positive in 15, falsely negative in 2, and not done in 2. By computed tomographic scan, CLNs were negative in 57 patients and positive in 2. The CLNs were positive in 23 of 54 patients eligible for CLN pathologic verification. All positive CLNs not identified by EUS (7 false-negative EUS) were microscopic foci in one or two nodes and were associated with T3 tumors. Sensitivity and specificity of EUS were 72% and 97%, respectively, compared with 8% and 100% for computed tomographic scan. When EUS identified CLNs, fine-needle aspiration confirmed positivity in 88% of cases. CONCLUSIONS: Endoscopic ultrasound with fine-needle aspiration is useful in the detection and confirmation of CLN metastasis. In T3 tumors of the distal esophagus, a negative EUS result does not substantiate absence of CLN disease. Endoscopic ultrasound with fine-needle aspiration may be important in guiding treatment for patients with distal adenocarcinoma and documenting disease before neoadjuvant therapy.

Adenocarcinoma↗
PubMed1999

Bile duct stones and laparoscopic cholecystectomy: a decision analysis to assess the roles of intraoperative cholangiography, EUS, and ERCP.

BACKGROUND: The least costly management strategy for patients undergoing laparoscopic cholecystectomy is unclear. METHODS: A decision model incorporating cost ratios, test accuracy, complication, and failure rates was used to determine the costs of 4 peri-laparoscopic cholecystectomy strategies: endoscopic retrograde cholangiopancreatography (ERCP), intraoperative cholangiography (IOCG), endoscopic ultrasound (EUS), and expectant management. RESULTS: Expert IOCG is least costly for intermediate-risk patients when the risk of stones is between 17% and 34%. If expert EUS is available, 0% to 10% ("low" risk) merits expectant management; 11% to 55% ("intermediate" risk) merits EUS; and greater than 55% ("high" risk) merits ERCP. Thresholds were most sensitive to changes in the risks of symptoms and complications due to retained stones; and to procedural costs, sensitivity, and success rates. Neither IOCG nor EUS appears likely to reduce overall costs unless their accuracy and success rates are greater than 90% and their procedural cost is less than 60% to 70% that of ERCP. When neither are available, ERCP is preferable when the risk of stones is greater than 22%. Thresholds were relatively insensitive to changes in the risk and severity of ERCP-induced pancreatitis. CONCLUSIONS: The least costly strategy for laparoscopic cholecystectomy patients depends primarily on the risk of stones and stone-related symptoms, but procedural costs and operator expertise are also critical.

Cholangiography↗
PubMed1999

Role of EUS in the preoperative staging of pancreatic cancer: a large single-center experience.

BACKGROUND: Current methods for staging pancreatic cancer can be inaccurate, invasive, and expensive. Endoscopic ultrasound (EUS) is reported to be highly accurate for local staging of gastrointestinal tumors including pancreatic cancer. The aim of this study was to assess the utility of EUS and CT for staging pancreatic cancer by comparing staging accuracies in surgical patients and evaluating the potential impact of EUS staging and training. METHODS: This was a preoperative comparison of the diagnostic operating characteristics of these procedures in a referral-based academic medical center. Data were collected on 151 consecutive patients referred with confirmed pancreatic cancer between April 1990 and November 1996. All patients had preoperative CT and EUS performed for staging. In patients undergoing surgery, the surgical staging and/or findings were used to confirm EUS and CT staging. RESULTS: Eighty-one (60%) of 151 patients underwent surgery and made up the study subset. In these 81 patients, surgical exploration provided a final T staging in 93% (75 of 81), N staging in 88% (71 of 81) and data on vascular invasion in 93% (75 of 81). In the surgical patient group, with surgical correlation, EUS accuracy for T staging was as follows: T1 92%, T2 85%, T3 93%, and for N staging was: N0 72%, and N1 72%. CT accuracy for T staging was as follows: T1 65%, T2 67%, T3 38%, and for N staging was as follows: N0 52% and N1 100%. CT failed to detect a mass in 26% of patients with a confirmed tumor at surgery. Overall accuracy for T and N staging was 85% and 72% for EUS and 30% and 55% for CT, respectively. The ability to accurately predict vascular invasion was 93% for EUS and 62% for CT (p < 0.001). EUS was 93% accurate for predicting local resectability versus 60% for CT (p < 0.001). Last, the data were divided into two groups for the senior endosonographer's experience: procedures performed between 1990 and 1992 (98 cases) and 1993 and 1994 (53 cases). This analysis revealed that 7 of 9 instances of mis-staging (78%) occurred in the earlier group, during the learning phase for EUS. CONCLUSIONS: EUS is more accurate than CT for staging pancreatic malignancies, including predicting vascular invasion and local resectability. EUS staging was significantly better than CT for T1, T2, and T3 tumors. EUS staging accuracy improved after 100 cases, thus suggesting a correlation between the accuracy of EUS staging and the number of procedures performed.

Adult↗
PubMed1999

A multicenter U.S. experience with EUS-guided fine-needle aspiration using the Olympus GF-UM30P echoendoscope: safety and effectiveness.

BACKGROUND: The aim of this study was to determine the safety, efficacy, and accuracy of endoscopic ultrasound (EUS)-guided fine-needle aspiration using the GF-UM30P echoendoscope. METHODS: GF-UM30P-guided EUS-guided fine-needle aspiration results from 3 EUS referral centers were prospectively recorded. Successful sampling required that the needle tip be seen within the lesion on at least 1 pass. Aspirates were considered adequate if they were diagnostic for cancer, contained suspicious or atypical cells, or were adequately cellular for interpretation but nondiagnostic. RESULTS: EUS-guided fine-needle aspiration was attempted on 162 lesions in 152 patients with no complications. Sampling was successful in 150 of 162 (93%) attempts (mean lesion size 2.5 +/- 1.2 cm (range 0.7 to 6.0 cm). Aspirates were adequately cellular in 138 of 162 (85%) attempts (43% diagnostic, 15% suspicious and/or atypical cells, 27% adequate cellularity but nondiagnostic). Sampling failed in 12 of 162 (7%) attempts. Ten of 12 (83%) failures and 11 of 12 (92%) inadequate aspirates occurred when lesions measured less than 2 cm. The sensitivity for malignancy was 93% if only successfully sampled lesions with surgically confirmed negative results were included. However, it was 68% if all attempts were included and when unconfirmed high/moderate suspicion negative results were counted as false negatives and low suspicion negative results as true negatives. CONCLUSIONS: The GF-UM30P may be clinically useful for EUS-guided fine-needle aspiration if a curved linear array instrument is unavailable.

Biopsy, Needle↗
PubMed1999

Endoscopic injection of bleeding esophageal varices with a poly-N-acetyl glucosamine gel formulation in the canine portal hypertension model.

BACKGROUND: It has been shown that poly-N-acetyl glucosamine produces rapid hemostasis by stimulating erythrocyte aggregation. Endoscopic injection of this substance may be effective in the treatment of bleeding varices. METHODS: In eight heparinized dogs with a bleeding esophageal varix greater than 2 mm in diameter, 2.5% to 3.5% poly-N-acetyl glucosamine gel was injected intravariceally and paravariceally. Endoscopy, endosonography, and histopathology were performed at 1, 7, 21, and 90 days after injection. RESULTS: In all cases, the variceal hemorrhage was stopped with three to four injections of a mean total gel volume of 1.9 mL. No recurrence of bleeding, ulceration, or stricture formation occurred. Through replacement of the gel by connective tissue, the varix was permanently obliterated in its whole course in five cases and in more than 70% of its length in three cases. No embolization and no poly-N-acetyl glucosamine antibodies were detected. CONCLUSIONS: Endoscopic injection of bleeding esophageal varices in this animal model with the use of poly-N-acetyl glucosamine gel was an effective and safe method for stopping the hemorrhage and inducing permanent varix obliteration.

Acetylglucosamine↗
PubMed1999

Prospective assessment of the utility of EUS in the evaluation of gallstone pancreatitis.

BACKGROUND: The ability to identify common bile duct stones by noninvasive means in patients with acute biliary pancreatitis is limited. The aim of this study was to prospectively evaluate the ability of endosonography (EUS) to identify cholelithiasis and choledocholithiasis and predict disease severity in patients with nonalcoholic pancreatitis. METHODS: EUS was performed immediately before endoscopic retrograde cholangiopancreatography (ERCP) by separate blinded examiners within 72 hours of admission. Gallbladder findings were compared between EUS and transabdominal ultrasonography (US). Using endoscopic extraction of a bile duct stone as the reference standard for choledocholithiasis, the diagnostic yield of EUS was compared with transabdominal US and ERCP. Features identified during endosonographic imaging of the pancreas were correlated with length of hospitalization. RESULTS: Thirty-six patients were studied. EUS and transabdominal US were concordant in their interpretation of gallbladder findings in 92% of patients. The sensitivity of transabdominal US, EUS, and ERCP for identifying choledocholithiasis was 50%, 91%, and 92% and the accuracy was 83%, 97%, and 89%, respectively. Length of hospital stay was longer in patients with peripancreatic fluid (9.2 vs. 5.7 days, p < 0.1) and shorter in patients with coarse echo texture (2.6 vs. 7.2 days, p < 0.05) demonstrated on EUS. CONCLUSIONS: EUS can reliably identify cholelithiasis and is more sensitive than transabdominal US in detecting choledocholithiasis in patients with biliary pancreatitis. EUS may be used early in the management of patients with acute pancreatitis to select those who would benefit from endoscopic stone extraction. The utility of EUS for predicting pancreatitis severity requires further investigation.

Abdomen↗
PubMed1999

Diagnosis of pancreas divisum by endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: During pancreatobiliary imaging by endoscopic ultrasound (EUS) at the authors' institution, it is customary to attempt to obtain the "stack sign", where the bile duct and the pancreatic duct can be seen to run in parallel through the pancreatic head. We suspected that such a view may not be attainable in patients with pancreas divisum because of the short ventral pancreatic duct. The aim of the study was to investigate whether the presence of pancreas divisum could be suspected on the basis of EUS findings. PATIENTS AND METHODS: The stack sign is obtained by positioning the echo endoscope in the long scope position with the transducer in the duodenal bulb. The balloon is then inflated and advanced snugly into the apex of the bulb. From this position, the bile duct (closest to the transducer) and the pancreatic duct can be seen to run in parallel through the pancreatic head. We attempted to obtain a stack sign during EUS examinations of six patients with pancreas divisum. EUS was done in these patients to look for evidence of chronic pancreatitis and the pancreas divisum was confirmed by endoscopic retrograde pancreatography. An attempt to obtain the stack sign was also made in 30 patients who had EUS for pancreatobiliary indications but did not have pancreas divisum. RESULTS: In only two out of six patients with pancreas divisum (33 %) were we able to obtain a stack sign. This was significantly different from the rate of observation of a stack sign in 83.3 % (25/30) of patients who did not have pancreas divisum (P=0.04). Of the two patients with pancreas divisum in whom a stack sign was seen, the ventral duct was markedly dilated (6.6 mm) in one, and the other patient had an unusually large ventral pancreas. CONCLUSIONS: The absence of a stack sign during pancreatobiliary imaging by EUS may suggest the diagnosis of pancreas divisum.

Congenital Abnormalities↗
PubMed1999

Endoscopic ultrasonography with fine-needle aspiration: an accurate and simple diagnostic modality for sarcoidosis.

BACKGROUND AND STUDY AIMS: Sarcoidosis is a chronic multisystem granulomatous disease that is often diagnosed after a finding of hilar and mediastinal lymphadenopathy on a chest radiograph. This often requires further evaluation by transbronchial biopsy or other clinical parameters. The present study is a descriptive, retrospective one using endoscopic ultrasound with fine-needle aspiration (EUS-FNA) of mediastinal lymph nodes in seven patients with sarcoidosis. PATIENTS AND METHODS: Among 108 consecutive patients who underwent EUS-FNA of mediastinal lymph nodes for various clinical indications between July 1994 and October 1997, seven patients were found to have sarcoidosis on EUS-FNA, and the EUS morphology was studied in these patients. RESULTS: Sarcoidosis was diagnosed in seven patients using endosonographic characteristics and clinical follow-up. EUS with FNA showed cytological evidence of sarcoidosis in six patients. Seven patients were found to have subcarinal lymph nodes, and six patients had abnormally enlarged aortopulmonary (AP) window lymph nodes. The nodes in all patients had three endosonographic criteria for malignancy. The long axis of the largest mediastinal lymph nodes measured 3.44+/-1.42 cm (range 1.8-6.0 cm). The short axis measured 2.50+/-0.69 (range 1.0-4.0 cm). The average number of nodes seen in each patient was 2.80+/-0.75 (range 2-4). The nodes in all seven patients were discrete and well demarcated. A central hyperechoic strand was evident in these nodes in four patients (57%). There were no complications. CONCLUSIONS: Mediastinal lymph nodes in patients with sarcoidosis appear to have specific echo characteristics, and EUS-FNA can be used for confirmatory tissue diagnosis.

Adult↗
PubMed1999

Endoscopic ultrasound guided fine needle aspiration biopsy: a large single centre experience.

BACKGROUND: Endoscopic ultrasound guided fine needle aspiration biopsy (EUS-FNA) is a recent innovation in the evaluation of gastrointestinal and pulmonary malignancies. AIMS: To review the experience with EUS-FNA of a large single centre. METHODS: 333 consecutive patients underwent EUS-FNA. Follow up data were available on 327 lesions in 317 patients, including 160 lymph nodes, 144 pancreatic lesions, 15 extraintestinal masses, and eight intramural tumours. RESULTS: A primary diagnosis of malignancy was obtained by EUS-FNA in 62% of patients with clinically suspicious lesions. The overall accuracy of EUS-FNA for the diagnosis of malignancy was 86%, with sensitivity of 84% and specificity of 96%. With respect to lesion types, the sensitivity, specificity, and accuracy were 85%, 100%, and 89% for lymph nodes; 82%, 100%, and 85% for pancreatic lesions; 88%, 100%, and 90% for perirectal masses; and 50%, 25%, and 38% for intramural lesions, respectively. Compared with size and sonographic criteria, EUS-FNA in the evaluation of lymph nodes provided superior accuracy and specificity, without compromising sensitivity. Inadequate specimens were obtained from only six patients, including 3/5 with stromal tumors. Only one complication occurred. CONCLUSIONS: EUS-FNA is safe and can readily obtain tissue specimens adequate for cytopathological diagnoses. Compared with size and sonographic criteria, it is a superior modality for the detection of nodal metastases. While providing accurate diagnosis of pancreatic and perirectal malignancies, results suggest the technique is less useful for intramural lesions.

Adolescent↗
PubMed1999

The ultraflex stents for malignant esophageal obstruction.

Ultraflex esophageal stents have contributed to the tremendous success of self-expanding metal stents (SEMS) in the treatment of esophageal cancer because they are easy and safe to insert. With an eye to improving clinical outcome, the Ultraflex stent design has been in a state of constant evolution since its introduction. However, as with other SEMS, a high reintervention rate remains a challenging problem.

Alloys↗
PubMed1998

Endoscopic electrohydraulic lithotripsy in the management of pancreatobiliary lithiasis.

BACKGROUND: Clinical evaluation of intraoperative endoscopy with electrohydraulic lithotripsy (EHL) in the management of 13 patients with pancreatobiliary lithiasis was undertaken. METHODS: Ten patients with chronic pancreatitis with intraductal lithiasis in the head and three with biliary lithiasis (one choledochal, one cystic, one right intrahepatic) underwent intraoperative endoscopy with EHL. Shock waves were applied by visual contact with a 3-Fr gauge EHL probe until all stones were fragmented and irrigated free. All pancreatitis patients had failed ERCP attempts to stent their pancreatic ducts secondary to ductal lithiasis. Patients with pancreatic stones underwent lateral pancreatojejunostomy. Biliary stone patients underwent laparoscopic cholecystectomy with common duct exploration (two cases) and open cholecystectomy with choledochoduodenostomy (one case). RESULTS: Intraductal stone eradication was successful in all patients. Transampullary visualization of the duodenum was achieved in eight cases. Average EHL time was 65 min. There was no evidence of postoperative pancreatitis, cholangitis, or retained common duct stones. CONCLUSION: Intraoperative pancreatobiliary endoscopy with EHL is safe and effective in the eradication of pancreatic and bile duct stones. This novel technique represents a valuable adjunct in the management of chronic fibrocalcific pancreatitis with ductal lithiasis in the head region and in the open and laparoscopic management of intra- and extrahepatic bile duct stones.

Adult↗