Anand V. Sahai

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.

3892 How many supervised procedures does it take to become competent in eus?-results of a multicenter three year study.

Background: The amount of experience required to train new endosonographers is unknown. Competency in technical performance is likely to precede interpretive competence. Methods: Over a 3 year period, recognized experts in EUS provided one on one proctorship; evaluated the performance of new trainees in the specific categories listed below; and rated each procedure category as 0=Failed; 1=Unsatisfactory; 2=Satisfactory; 3=Excellent. Competency was defined as achieving a consistent score of 2. Results:10 third tier fellowship trainees and 2 PGY 6 trainees were evaluated. All were male. Only one had performed EUS prior to beginning his training. None had prior abdominal US experience. 10/12 were trained in ERCP. Mean number of ERCPs performed before EUS training was 229 ( SD 167). The median (range) of the number of EUS procedures required for competency is listed for the following categories: Esophageal Intubation 1(1-21), Pylorus Intubation 2(1-14), Duodenal Intubation 2(1-23), Esophageal wall visualization 10(1-36), Gastric wall 15(1-47), Mediastinum 10(1-33), Celiac axis 25(8-36), Pancreas body and tail 26(1-34), Pancreas head 34(15-74), CBD/PD 55(13-135), Ampulla 54(13-134) , Normal anatomy interpretation 54(9-92), and Pathology interpretation 60(16-134). The number of procedures needed to successfully visualize the head, tail and body of the pancreas was not different among the trainees who had performed more than 100 ERCPs compared to those who had performed less (p>0.05). In addition, the number of procedures needed to adequately interpret normal anatomy or EUS related pathology was not different among the two groups. Conclusions: With intensive hands-on experience and tutelage by an expert in a facility performing a high volume of EUS procedures, a trainee may become competent to perform EUS within a relatively short time-period. There is, however, a broad range in the ability to interpret normal anatomy and pathology. This information may alter the current pattern of advanced training and also be of importance to private practitioners wishing to develop skills in EUS. This study was support by a grant from the American Digestive Health Foundation.

3491 Preliminary experiences of three-dimensional endoscopic ultrasonography in the united states.

INTRODUCTION: The advent of low cost computer power has greatly impacted body imaging resulting in a proliferation of technologies incorporating 3-D reconstruction. AIM: To image a variety of UGI lesions with a prototype 3-D EUS catheter probe to determine its potential clinical applications. METHOD: The 3D-EUS imaging system (Olympus Optical, Tokyo) consists of a 12 and 20 MHz ultrasonic probe (UM-3D2R, UM-3D3R), a motor unit, an ultrasound processor (EU-M30), and a computer for image processing (EU-IP2). Scanning and storing time is 4 to 13 sec. The ultrasound probe is housed in a clear sheath filled with water. The motor moves the probe radially (360°) and linearly (4cm). Images are stored and processed later. In all cases, the radial and linear images were reviewed and judgment was rendered as to whether combined imaging provided clinical benefit. Esophageal cases were performed using a condom placed over the end of a two channel endoscope. RESULT: Between 5/99 and 11/99, 13 3-D EUS cases were performed (2 esophageal cancer, 3 Barretts esophagus, 4 esophageal SMT, 1 gastric SMT, 1 mucinous ductal ectasia, 1 common bile duct stricture). The simultaneous display of linear and radial images made imaging and interpretation of images of SMT easier but did not provide unique and significant advantages. Imaging and evaluation of Barretts esophagus and biliary strictures was significantly better with the 3-D system because of the volume of area that can be scannedfrom a single position. CONCLUSION:We suggest that the simultaneous linear and radial images produced by this instrument may improve diagnosis in some circumstances. Prospective trials based on this data are ongoing. Volume rendering will be possible in the near future which may further expand the application of 3-D EUS.

⁎4588 Endoscopic ultrasound as a first-line diagnostic and staging test after ct in patients with suspected or proven lung cancer: yield in 122 consecutive patients.

Background: 50% of lung cancer patients have mediastinal lymph node metastases. Proof of ipsilateral node (N2) or contralateral node (N3) involvement contraindictates surgery as primary treatment, but usually requires mediastinoscopy. EUS-guided fine needle aspiration (FNA) provides access to posterior mediastinal nodes and may therefore prevent mediastinoscopy and document surgically incurable disease. Aim: To verify the yield of EUS as a first-line diagnostic and staging modality in patients with suspected or proven lung cancer by CT and/or bronchoscopy. Methods: EUS-FNA was used as a first-line diagnostic and/or staging test in consecutive patients with suspected or proven lung cancer in whom CT showed mediastinal disease accessable for EUS-FNA. Results: 122 consecutive patients had disease that appeared amenable to EUS-FNA: 70 with suspected and 52 with proven lung cancer. Overall, EUS was attempted in 118 (97%) cases: 10 masses and 108 nodes (47% level 7 [AP window]; 32% level 5 [subcarina]; 15% levels 5 & 7; and 6% other node levels). There were no complications. A cytological diagnosis of cancer was obtained in 46/70 (69%) of suspected cancers. The yield for nodal staging was calculated on an “intent to stage” basis. Mediastinal node involvement was documented cytologically in 73/112 (60%) cases where staging was the aim: 37/112 (33%) N2 and 36/112 (32%) N3 nodes. See Table. Conclusions: 1) EUS has a high yield in patients with suspected or proven lung cancer with mediastinal disease by CT. 2) A cytological diagnosis of cancer is obtained in 2/3 patients with suspected cancer. 3) Cytological proof of mediastinal ipsilateral or contralateral disease is obtained in 2/3 patients.