Hany Kashani MD, Presenter: Nothing to Disclose

Tae Bong Chung MD, Abstract Co-Author: Nothing to Disclose

Ravi Menezes PhD, Abstract Co-Author: Nothing to Disclose

Chris Ray, Abstract Co-Author: Nothing to Disclose

Heidi C. Roberts MD, Abstract Co-Author: Nothing to Disclose

Narinder S. Paul MD, Abstract Co-Author: Research support, Toshiba Corporation

To determine whether lobar location and final pathological diagnosis of a lung nodule influence the likelihood of indeterminate cytology during initial CT-FNAB.

A retrospective, single centre study of 1569 patients referred for CT-FNAB from Oct 1993 - Dec 2006, to evaluate a suspicious lung lesion. Lesion parameters including size (mm), lobar location, attenuation (HU), lesion depth and lung path were recorded. CT-FNAB was performed using a 19/21G co-axial needle technique supervised by a sub-specialty trained chest radiologist. On site cytologists reviewed all samples and lesions were categorized as determined (definite diagnosis of benign or malignant) or indeterminate. Patients with indeterminate lesions were followed for a mean period of 7.47 months (range 0.3-124) to establish a final diagnosis.

78.1% (1225/1569) of lesions had determined histology with 86% (1054/1225) malignant lesions. Nodules with indeterminate cytology were smaller than those with a definite initial diagnosis (nodule diameters 26 ± 21 mm and 31 ± 21.4 mm respectively, p < 0.0001). Of 344 indeterminate lesions, 145 (42%) patients were outside referrals without follow up data. The remaining 58% (199/344) of patients had a final diagnosis determined by follow up CT (30%), resection (32%), repeat CT-FNAB (20%), alternate biopsy (13%) or clinical review (5%). 65% (129/199) of these were malignant (48% NSCLC) and 35% (70/199) benign. Lobar location of indeterminate (I) and determinate (D) biopsies (%): LUL (20 I, 80 D), Lingula (34 I, 66 D), LLL (24 I, 76 D), RUL (18 I , 82 D), RML (32 I, 68 D), RLL (23 I, 77 D). The Odds ratio (95% CI) for an indeterminate biopsy by lobar location was: RUL 1.00, RML 2.07 (1.26, 3.42), RLL1.35 (0.96, 1.91), LUL 1.11 (0.79, 1.58), Lingula 2.30 (1.16, 4.58) and LLL 1.41 (0.97, 2.03). The Odds ratio (95% CI) for an indeterminate biopsy by final diagnosis is as follows: NSCLC 1.00, SCLC 1.83 (0.75, 4.44), benign 7.27 (5.04, 10.48), metastases 8.88 (4.61, 17.10).

Lung nodules located in the lingula and RML have a greater than 2 fold increased likelihood of an indeterminate initial CT-FNAB biopsy. Lung metastases and benign lesions have a 9 fold and 7 fold increased likelihood for an indeterminate initial CT-FNAB, respectively.

The lobar location and likely histology of a suspicious lung nodule should be considered when assessing the likelihood of a successful CT-FNAB.

Kashani, H, Chung, T, Menezes, R, Ray, C, Roberts, H, Paul, N, Does Lobar Location and Final Pathological Diagnosis of Lung Nodules Predispose to Indeterminate Cytology during Initial CT-FNAB?.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11006261.html