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Biomedical subjects

R H Hawes

Publications and source records attributed to R H Hawes.

At least 91 records · Page 5Linked to original sources
PubMed1997

Differentiation of benign from malignant pancreatic masses by endoscopic ultrasound.

BACKGROUND: It is often difficult to determine whether a mass in the pancreas is benign or malignant. The goal was to evaluate whether endoscopic ultrasound (EUS) can reliably establish whether a mass is benign or malignant. METHODS: One hundred five patients with possible pancreatic tumors were referred for EUS. Those who were found to have a lesion suspicious for carcinoma and did not have a known malignancy also underwent EUS-guided FNA. RESULTS: A mass suspicious for cancer was identified in 73 patients, whereas inflammatory changes or a normal pancreas was noted in 32 patients. Four of the latter 32 patients were subsequently found to have cancer. EUS-guided FNA was performed on 47 of the 73 patients with a suspicious mass and was read as cancer in 27 patients, atypia in 10 patients, and benign in 10 patients. All 10 patients with atypia were subsequently confirmed to have cancer, and 6 of the 10 patients with a benign FNA were proved to have a tumor at surgery. EUS could differentiate the lesion as malignant with a sensitivity of 95%, specificity 88%, positive predictive value 95%, and negative predictive value 88%. CONCLUSIONS: Radial array EUS is helpful in supporting or refuting a diagnosis of cancer in a patient with a pancreatic mass. Although EUS-guided FNA can confirm the diagnosis, a negative FNA should not preclude exploration when clinically indicated.

Adenocarcinoma↗
PubMed1997

Histological correlates to pig gastrointestinal wall layers imaged in vitro with the magnetic resonance endoscope.

BACKGROUND & AIMS: The magnetic resonance endoscope consists of a nonferromagnetic endoscope with a receiver coil incorporated into its tip. The aim of this study was to define the anatomic correlates of the gastrointestinal wall layers imaged in vitro with the magnetic resonance endoscope. METHODS: Twenty-two tissue specimens from various segments of the porcine gastrointestinal tract were imaged with the magnetic resonance endoscope using up to four different scanning sequences. Cyanoacrylate, serving as a marker, was randomly injected into the tissue strips before imaging. Histological sections were then compared with the magnetic resonance images. RESULTS: T1-weighted spin echo sequences yielded the highest image quality and typically showed three wall layers that corresponded to distinct histological layers. The mucosa showed high signal intensity, the submucosa low signal intensity, and the muscularis propria an intermediate signal intensity. In the esophagus and rectum, the muscularis propria could be visualized as separate circular and longitudinal layers. CONCLUSIONS: In vitro imaging with the magnetic resonance endoscope shows three to five wall layers of the porcine gastrointestinal tract depending on the segment scanned. This degree of gut wall resolution suggests that endoscopic magnetic resonance imaging may have potential for local staging of gastrointestinal tumors.

Animals↗
PubMed1997

Endosonographic differentiation of benign and malignant stromal cell tumors.

BACKGROUND: Endosonography (EUS) is a valuable technique for diagnosing gastrointestinal stromal cell tumors. However, EUS features that are predictive of malignancy in these tumors have not been defined. METHODS: Videotapes and photographs of EUS examinations performed prior to surgical resection of 35 stromal cell tumors (9 malignant) were blindly reviewed by a single examiner. EUS features associated with malignancy were determined. Interobserver agreement in interpreting these features was then measured among a panel of five expert endosonographers who judged EUS videotapes of 35 resected stromal cell tumors (10 malignant). RESULTS: Stepwise logistic regression analysis demonstrated that tumor size (diameter > 4 cm), irregular extraluminal border, echogenic foci, and cystic spaces were independently associated with malignancy in stromal cell tumors (p < 0.05). Interobserver agreement for irregular extraluminal border, echogenic foci, and cystic spaces, as measured by mean kappa statistic, was 0.43, 0.39, and 0.28, respectively. For the five experts, the sensitivity for detecting malignancy ranged between 80% to 100% when at least two of the three features were judged to be present. The likelihood of finding malignancy ranged between 0% to 11% for the experts when all three features were judged absent. CONCLUSIONS: Tumor size and certain EUS features are useful for predicting malignancy in stromal cell tumors. Absence of these features indicates benign disease. Agreement among experts in interpreting these EUS features is fair to moderate.

Diagnosis, Differential↗
PubMed1997

A comparison of the accuracy of echo features during endoscopic ultrasound (EUS) and EUS-guided fine-needle aspiration for diagnosis of malignant lymph node invasion.

BACKGROUND: The purpose of this study was to re-evaluate echo features of lymph nodes during endoscopic ultrasound and assess the utility of these echo features and endoscopic ultrasound-guided fine-needle aspiration in predicting malignant lymph node invasion. METHODS: Thirty-five lymph nodes in 25 patients with lung, esophageal, and pancreatic cancer were evaluated by endoscopic ultrasound. Endoscopic ultrasound examinations were performed with a radial scanning echoendoscope. Confirmation of benign lymph nodes was obtained by surgical resection while malignant lymph nodes were confirmed by real-time endoscopic ultrasound-guided fine-needle aspiration with a linear array echoendoscope. RESULTS: Nineteen benign lymph nodes and 16 malignant lymph nodes in the mediastinum, celiac axis, and the peripancreatic area were included in the study. The following echo features were compared between benign and malignant lymph nodes: size greater than 1 cm, hypoechoic, distinct margins, and round shape. No single feature independently predicted malignant invasion. When all four of the above features were present in the same lymph node, the accuracy for predicting malignant invasion was 80%. However, all four features of malignant involvement were present in only 25% (4 of 16) of malignant lymph nodes. Our study also suggests that the above echo features may be a less reliable predictor of malignant invasion in pulmonary malignancies when compared to gastrointestinal cancers. Endoscopic ultrasound-guided fine-needle aspiration of lymph nodes in 22 patients revealed malignant lymph node invasion in 16 and benign cells in 6 patients. CONCLUSION: Endoscopic ultrasound-guided fine-needle aspiration is an important adjunct for accurate lymph node assessment for malignancy.

Biopsy, Needle↗
PubMed1997

Endoscopic ultrasound-guided fine-needle aspiration biopsy using linear array and radial scanning endosonography.

BACKGROUND: Endoscopic ultrasound (EUS) accurately stages gastrointestinal malignancies but is less able to differentiate between neoplastic and inflammatory processes. EUS-guided fine-needle aspiration (EUS FNA) has been reported useful for obtaining a diagnosis in suspected gastrointestinal lesions. We report our entire experience with EUS FNA using both radial and linear array endosonography, including our diagnostic accuracy and complication rate. METHODS: Two hundred eight consecutive patients (119 men, 89 women) referred for EUS evaluation of suspected gastrointestinal or mediastinal masses underwent EUS-guided FNA. We performed EUS FNA using radial scanning or linear array endosonography and a 23 gauge, 4 cm needle or a 22 gauge, 12 cm needle. Data collected included lesion types, number of passes, complications, and diagnostic accuracy. RESULTS: Two hundred eight lesions were targeted, with a total of 705 FNA passes (mean 3.39 passes/patient). Overall diagnostic accuracy for our study population was 87% with a 89% sensitivity and 100% specificity. The diagnostic accuracy for each subgroup was 95% for mediastinal lymph node, 85% for intra-abdominal lymph node, 85% for pancreatic, 84% for submucosal, and 100% for perirectal masses. EUS FNA provided an adequate specimen in 90% of patients. The FNA results were similar for both types of endosonography. We observed immediate complications in 2% (4 of 208) of patients. All complications occurred with EUS FNA of pancreatic lesions and consisted of bleeding and pancreatitis in 2 patients each. For EUS FNA of pancreatic masses there was a 1.2% (2 of 121) risk of pancreatitis, 1% (1/121) risk of severe bleeding, and risk of death in less than 1%. CONCLUSIONS: EUS-guided FNA appears to be technically feasible, safe, and accurate for obtaining diagnostic tissue of suspicious gastrointestinal and mediastinal lesions and provides important preoperative information.

Adolescent↗
PubMed1997

Transpapillary stenting of proximal biliary strictures: does biliary sphincterotomy reduce the risk of postprocedure pancreatitis?

BACKGROUND: Pancreatitis after biliary stenting is a rare complication. To reduce this risk, some endoscopists routinely perform biliary sphincterotomy before stenting, but the value of this practice is not established. METHODS: The incidence of pancreatitis was reviewed in patients undergoing biliary stenting with and without a biliary sphincterotomy. RESULTS: Postprocedure pancreatitis occurred in 4 of 83 (4.8%) patients treated with transpapillary biliary stents. Patients with proximal biliary strictures were at significantly increased risk for postprocedure pancreatitis (4 of 24) versus those with distal or no strictures (0 of 59) (p = 0.006). The four patients with pancreatitis after stenting had not undergone sphincterotomy. Of those treated conservatively, two cases were graded severe (one fatal), and one was mild. The other patient was markedly symptomatic from pancreatitis, but improved dramatically after treatment with a needle-knife sphincterotomy done within 24 hours of the original ERCP. CONCLUSION: The risk of pancreatitis following transpapillary biliary stenting is increased in patients with proximal biliary strictures. Such lesions (malignant or benign) may serve as a fulcrum, leading to medial deflection of the stent and compression of the pancreatic orifice. The hypothesis that sphincterotomy may decrease the risk of biliary stent-induced obstructive pancreatitis should be tested in patients with proximal biliary strictures.

Adult↗
PubMed1997

Multidisciplinary approach to the treatment of pediatric pancreaticobiliary disorders.

A multidisciplinary approach using traditional open surgery, endoscopic retrograde cholangiopancreatography (ERCP) and laparoscopic surgery has revolutionized the care of the adult with pancreaticobiliary disease. This study focuses on a similar collaborative effort to diagnose and treat children with pancreaticobiliary disorders. Charts of all patients treated on the pediatric surgery service between June 1990 and May 1995, who also underwent ERCP, were abstracted for disease process, presenting symptoms, laboratory evaluation, surgical or endoscopic procedures, and eventual outcome. Twenty-six children were identified, ranging from 6 months to 19 years of age. Pancreaticobiliary disorders included pancreas divisum (n = 1), choledochal cyst (n = 4), pancreaticobiliary trauma (n = 4), cholelithiasis and choledocholithiasis (n = 17). The pancreaticobiliary tree was successfully visualized by ERCP in 25 of 26 (96%) patients. Fifteen of these patients also underwent attempted therapeutic endoscopic procedures, with 13 (87%) performed successfully. Three patients with choledochal cyst had stents placed preoperatively for cholangitis, all of whom have undergone successful choledochal cyst excision. Two trauma patients underwent attempted stenting of a bile leak and bile duct stricture, respectively, both of which were unsuccessful, necessitating surgical correction. Seventeen patients with cholelithiasis underwent ERCP to rule out choledocholithiasis. Ten patients were found to have common duct stones, and all stones were endoscopically extracted, including those in a 6-month-old child. Overall survival rate was 96% (25 of 26), with the one death occurring in a trauma patient unrelated to his pancreaticobiliary disorder. A multidisciplinary approach using traditional open surgery, ERCP and laparoscopic surgery can successfully treat even young children with pancreaticobiliary disorders. In experienced hands, diagnostic ERCP and therapeutic endoscopic intervention can be performed successfully in most pediatric patients, greatly simplifying the surgical management of these potentially complex problems.

Adolescent↗
PubMed1997

Contrast-enhanced endoscopic ultrasonography with galactose microparticles: SHU508 A (Levovist).

BACKGROUND AND STUDY AIMS: To evaluate the utility of a suspension of galactose microparticles available as SHU508 A (Levovist) as a contrast agent during endoscopic ultrasonography (EUS). MATERIALS AND METHODS: Three sets of experiments were performed on three 20-25 kg swine (Sus scrofa) under general anesthesia. Upper EUS was performed with an echo endoscope with color Doppler capability (Pentax FG-32 UA). The celiac artery, superior mesenteric artery, aorta, portal vein, pancreas, and gastrointestinal wall were imaged by EUS. Multiple intravenous bolus injections of 400 mg/ml of SHU508 A were made, and their effect on color Doppler and gray-scale imaging during EUS was studied. RESULTS: After contrast injection there was a significant, visually noticeable enhancement of the color Doppler signals from the celiac artery, superior mesenteric artery, and portal vein. Vessels with weak to no color Doppler signals before injection of SHU508 A--for example, the celiac artery and superior mesenteric artery--were observed to have strong color signals after injection. The effect of SHU508 A on color Doppler imaging was easily appreciated subjectively without the need for complex quantitative measurements. No visually noticeable color Doppler enhancement was seen in vessels such as the aorta that had a very pronounced color Doppler signal even prior to the injection of contrast. Movement of particulate matter was seen in the portal vein on the gray scale. CONCLUSION: Intravenous SHU508 A as a contrast agent significantly enhances color Doppler signals during EUS. Vascualar contrast of this sort could potentially have a significant role in improving the accuracy of EUS in diagnosing malignant vascular invasion, the detection of occult pancreatic neoplasms, and the diagnosis of vascular thrombosis.

Animals↗
PubMed1997

Endoscopic ultrasound guided fine needle aspiration of malignant pancreatic lesions.

PURPOSE: To evaluate the accuracy, safety, and clinical utility of endoscopic ultrasound (EUS) guided fine needle aspiration (FNA) of pancreatic masses. METHODS: Forty-seven patients were referred for EUS with a pancreatic mass and suspicion of pancreatic cancer based upon painless obstructive jaundice, epigastric abdominal pain plus weight loss/anorexia, or idiopathic pancreatitis. All patients underwent EUS with both radial (Olympus UM20) and linear array (Pentax FG32-UA) systems. After TNM staging by EUS, ultrasound directed FNA of the pancreatic mass was performed using a 23 gauge, 4 cm long needle. RESULTS: EUS-guided FNA was performed in all 47 patients. Results: successful targeting = 100%, adequate cellularity = 100%, FINDINGS: adeno Ca = 25, squamous cell Ca = 1, lymphoma = 1, poorly differentiated Ca= 1, atypical cytology or suspicious for carcinoma = 9, no malignant cells = 10. The sensitivity, specificity, positive predictive value and negative predictive value of EUS-guided pancreatic FNA for the diagnosis of malignancy was 64%, 100%, 100% and 16% respectively. CONCLUSIONS: EUS with FNA is useful for detection of malignancy in a pancreatic mass. The procedure appears to have a complication rate of 2%. Impact of this technique on clinical management of patients needs further evaluation.

Adenocarcinoma↗
PubMed1997

MR endoscopy: preliminary experience in human trials.

The authors performed local staging of esophageal and rectal cancer (without pathologic correlation) with use of a nonferromagnetic magnetic resonance (MR) endoscope with a 3-cm-long receive-only coil embedded in its tip in 16 patients (eight with esophageal cancer and eight with anorectal cancer). Results with spin-echo sequences were optimal in all cases [corrected].

Anal Canal↗
PubMed1997

Sphincter of Oddi dysfunction is associated with chronic pancreatitis.

OBJECTIVES: Chronic pancreatitis can be caused by ductal obstruction resulting from cicatricial papillary stenosis, but sphincter of Oddi motility studies have been inconclusive in patients with established chronic pancreatitis. We sought to determine whether there is an association between papillary sphincter dysfunction and changes of early chronic pancreatitis. METHODS: Consecutive patients who underwent sphincter of Oddi manometry to investigate unexplained upper abdominal pain (n = 104) were assessed for evidence of chronic pancreatitis by pancreatic ductography, endoscopic ultrasound, and pancreatic fluid bicarbonate concentration. RESULTS: Sphincter of Oddi dysfunction patients were four times more likely (odds ratio = 4.6) to have evidence of chronic pancreatitis than were those without sphincter dysfunction (p = 0.01). Of 68 patients with sphincter of Oddi dysfunction, 20 (29%) had structural evidence of chronic pancreatitis. Twenty of 23 (87%) patients with chronic pancreatitis had sphincter of Oddi dysfunction. CONCLUSIONS: Sphincter of Oddi dysfunction is associated with changes of chronic pancreatitis in patients with unexplained pancreaticobiliary pain. Longitudinal follow-up is required to confirm these preliminary findings.

Adult↗
PubMed1996

Endoscopic ultrasound with fine-needle aspiration in the diagnosis and staging of lung cancer.

BACKGROUND: Esophageal endoscopic ultrasonographic (EUS) guidance for fine-needle aspiration (FNA) of mediastinal lymph nodes has been introduced only recently. The utility of EUS/FNA in diagnosing and staging bronchogenic carcinoma is unknown. METHODS: After a thoracic computed tomographic scan, 27 patients with known or suspected lung cancer underwent EUS. Accessible abnormal mediastinal lymph nodes were aspirated under EUS guidance. Patients with positive cytologic studies did not undergo further testing, whereas the remaining patients underwent mediastinal exploration. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were calculated for both chest computed tomography and EUS/FNA: RESULTS: Twenty-two of 27 patients had mediastinal adenopathy by computed tomography scan. Sixteen patients had positive findings on EUS, 15 with positive FNA (10 non-small cell lung cancer; 5 small cell lung cancer) and 1 with T4 status. Fourteen patients with positive FNA had lymph nodes sampled at level 5, level 7, or both. Of 11 patients with negative EUS/FNA, 2 had positive findings at operation (sensitivity 89%). The diagnosis of lung cancer was established in 7 patients. CONCLUSIONS: The results showed that EUS/FNA improves the accuracy of computed tomographic scan in the staging of lung cancer. By accessing lymph nodes at levels 5 and 7, EUS/FNA complements mediastinoscopy and is considered the staging modality of choice in these regions. Positive EUS/FNA can obviate the need for further invasive staging.

Biopsy, Needle↗