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Background: A new mechanical sector scanning echoendoscope designed for EUS-guided, fine-needle aspiration biopsy (FNAB) was prospectively evaluated. The technical feasibility, safety, and histocytologic FNAB results are reported. Methods: Eighty-six patients underwent 106 FNAB procedures. The new echoendoscope has a 2.8 mm accessory channel and an elevator. Target sites: pancreas 58, lymph nodes 43, and miscellaneous lesions 5. Lesions were punctured with a 0.7 mm needle and submitted for cytologic and histologic examination. Definitive diagnosis was by surgery or clinical follow-up. Results: The wide scanning field (250 degrees) enabled easy sonographic orientation for FNAB. Longitudinal needle visibility was “good” in 93% and 71% of transesophageal and transgastric procedures, respectively, but were compromised during most transduodenal procedures. Needle penetration of indurated pancreatic lesions failed in two patients, and in four additional patients pancreatic sampling succeeded only after a second attempt using an automated spring-loaded device. The mean number of passes was three. Ten percent of FNAB specimens were “inadequate”; excluding these, the diagnostic accuracy rate was 97%; sensitivity for malignancy was 88.5% and specificity was 100%. Conclusion: EUS-guided FNAB is feasible, safe, and accurate using the new mechanical puncture echoendoscope. Needle visibility needs to be improved, particularly for transduodenal FNAB. (Gastrointest Endosc 1998;47:335-40.)

Background : Previous studies have reported on endoscopic ultrasound–guided, fine needle aspiration biopsy using 22- to 25-gauge needles. We evaluated the histologic and cytologic yield of endoscopic ultrasound–guided, fine needle aspiration biopsy of the pancreas using an 18-gauge, Menghini-type core needle. Methods : Fine needle aspiration biopsy was performed in conjunction with a prototype 2.8 mm channel convex array echoendoscope. The core specimen was placed in formalin for cell block, and residual material was expelled on slides for cytology. Definitive diagnosis was established by surgery or clinical follow-up. Results : Of 45 patients who underwent fine needle aspiration biopsy, the needle failed to penetrate indurated pancreatic lesions in five. An average of 2.6 passes were performed in the remaining patients. Sufficient material for a histologic and/or cytologic diagnosis was obtained in 40 patients (histologic and cytologic yield of 68% and 75%, respectively). Combining the results of histology and cytology, the sensitivity and specificity for detection of malignancy was 76% and 100%, respectively. Histology confirmed the cytologic findings in 35 patients, providing additional tissue specific information. In three cases histology established a diagnosis of malignancy where cytology was not conclusively malignant. However, in three cases of surgically confirmed malignancy histology failed to detect malignancy, whereas cytology showed suspicious or malignant cells. The sensitivity of histology and cytology alone in detecting malignancy was 53% and 70%, respectively. Mild pancreatitis occurred after pancreatic fine needle aspiration biopsy in one patient. Conclusion : Core specimens for histology can be safely obtained using an 18-gauge needle. Histology provides tissue-specific information that complements cytology, but histology is less sensitive than cytology in detecting malignancy. (Gastrointest Endosc 1998;47:121-7)