E2848. Diffusion-Weighted MR Imaging for Improving the Diagnostic Efficacy of CT-Guided Transthoracic Lung Biopsy in Lung Tumor
  1. Konstantinos Frigkas; University General Hospital of Alexandroupolis
  2. Stavroula Theodorou; General Hospital of Ioannina
  3. Anastasios Vasilopoulos; University General Hospital of Alexandroupolis
  4. Soultana Foutzitzi; University General Hospital of Alexandroupolis
  5. Chrysovalantis Stylianou ; University General Hospital of Alexandroupolis
  6. Savvas Deftereos; University General Hospital of Alexandroupolis
CT-guided transthoracic lung biopsy (TLB) is the gold standard for diagnosing lung pathology in patients with suspected malignancy. The acquisition of adequate lung tissue from the biopsied lesion is important for providing the pathologist with specimens sufficient for the histological examinations. Occasionally, in large lesions with coexisting atelectasis and tumor necrosis TLB can be challenging as it may yield tissue samples insufficient for diagnosis. Diffusion-weighted MR imaging (DWI) may allow for assessment of cellularity within tumor, indicating an aggressive biological behavior. We used DWI to characterize large lung neoplasms and select the most appropriate site for biopsy. We present our results with CT-guided TLB and histopathology in a series of oncology patients.

Materials and Methods:
Thirty-six patients (aged 38 - 83 years) with suspected lung neoplasm underwent CT-guided TLB after biopsy planning on the MR imaging studies (group 1). Lung lesions had a diameter greater than 8 cm. The scans were conducted on a 1.5T MR scanner (Philips Multiva) using a 16-channel sense coil in the transverse plane, with the patient lying on his back. The imaging protocol included T2-weighted images and DWI, with diffusion coefficients of 50, 500, and 900 s/mm2. ADC values that ranged from 0,84 x 10-3 mm2 / sec to 1,35 x 10-3 mm2 / sec denoted high-cellularity lung tumors, on the ADC maps. TLBs were performed on a multislice CT-scanner (Philips Ingenuity Core 128), using 7 - 15 cm 16 - 18 G semiautomatic biopsy needles, with a 2-cm cutting length. The puncture points were chosen after fusing the available CT and MR images, and two pieces were acquired from each lesion. Tissue samples were sent for histological examination. Findings from a control group (group 2) of 100 patients who underwent CT-guided TLB without being examined with MRI were also evaluated. The acquisition of lung tissue adequate for diagnosis was set as the criterion to compare the two diagnostic approaches.

In group 1, the tissue acquired was adequate for diagnosis of malignancy in 33 of the 36 patients (92%). In group 2, tissue sampling was adequate for histological diagnosis in 83 of the 100 patients (83%). On histopathology, neoplasms were adenocarcinoma (15), squamous cell carcinoma (12), small-cell lung carcinoma (6) and metastasis (3). We found a statistical significance between groups (2 test, p < 0.038).

In comparing the diagnostic efficacy of CT-guided TLB planning, with or without DWI, we found that the TLB procedure yielded better results (p value < 0.038) in lung lesions when combined with DWI on the MR images. Because DWI may help in the differentiation of tumorous areas from regions of atelectasis, or the differentiation of consolidated lung parenchyma from necrotic regions, it appears that DWI may become a useful adjunct to the CT-guided TLB procedure.