Emerging Referral Patterns for Whole-Body Diffusion Weighted Imaging (WB-DWI) in an Oncology Center

Transcription

1 Emerging Referral Patterns for Whole-Body Diffusion Weighted Imaging (WB-DWI) in an Oncology Center Poster No.: C-1296 Congress: ECR 2014 Type: Scientific Exhibit Authors: G. Petralia 1, G. Conte 1, S. M. Vaziri Bozorg 2, P. Summers 1, S. Keywords: DOI: Alessi 1, M. Bellomi 1 ; 1 Milan/IT, 2 Tehran/IR Cancer, Diagnostic procedure, MR, Oncology /ecr2014/C-1296 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 18

2 Aims and objectives Introduction: Whole body diffusion-weighted imaging (WB-DWI) is increasingly used for the evaluation of oncology patients. Image acquisition in a reasonable time with free breathing and the growing evidence of its effectiveness in detection of metastasis make WB-DWI a considerable supplement to the anatomic imaging [1,2,3]. WB-DWI is performed without contrast material administration and there is no exposure to ionizing radiation, therefore can be safely used for assessment of pregnant patients (after first trimester) and screening of healthy subjects. These features are also significantly beneficial for the cancer patients who require long-term serial follow up imaging. WB-DWI typically involves a prolonged series of axial scans covering the area from the head to mid-thigh with diffusion sensitivity probed in 3 directions. The high b-value images are reconstructed and concatenated into an extended volume that can be reconstructed using maximum intensity projections (MIP) and displayed with inverted grey-scale to create a "PET-like" presentation for radiological reading (Figure 1). As well, the apparent diffusion coefficient (ADC) at each voxel is calculated and can be displayed in ADC map, usually in grey scale, which can also be concatenated into an extended volume. Impeded water diffusion in packed cellular tissue such as malignant tumors leads to high signal on DWI against the attenuated background on high b-value images. Good detection ability for highly cellular tumors such as lymphoma, myeloma, melanoma, breast cancer, neuroendocrine cancers, small cell cancers and pediatric cancers has been reported [1]. Bone marrow lesions are usually well-depicted by WB-DWI [1-4]; however, interpretation along with ADC map and conventional MRI is needed to avoid false positive results. WB-DWI has also high sensitivity for lymph node involvement although false positive results in evaluation of lymph nodes can occur due to the impeded diffusion in some reactive nodes [1, 3, 5]. WB-DWI has complementary role for PET-scan and some of the lesions with low FDG-uptake on PET-scan are better detected on WB- DWI [1]. Response of the metastatic lesions especially in bone can be assessed by WB- DWI, making this modality a valuable tool for patient follow up [1,3,4]. Availability, safety and high diagnostic yield of WB-DWI have resulted in emerging request for this modality and in this study we investigated the use of WB-DWI and the reasons for requests in our radiology department. Images for this section: Page 2 of 18

3 Fig. 1: Maximum intensity projection (MIP) reconstructed WB-DWI. Page 3 of 18

4 Methods and materials In 2009 we started to run the WB-DWI in a clinical trial (phase III) in patients with stage III melanoma, at high risk of developing metastases after primary tumor resection and regional lymph node dissection. Following good results in melanoma patients, in 2011 we started to perform WB-DWI in the referred oncologic patients as a part of their routine clinical evaluation, for the following clinical indications: staging, screening, followup and problem solving (in cases with conflicting or inconclusive results from the other modalities) (Figure 2,3). In 2013, we started to use WB-DWI for screening of healthy subjects. We audited all WB-DWI exams performed in our institution form April 2009 to October Each exam in referrals (referred oncologic patients and healthy subjects) was classified according to clinical setting as follows: 1. "Only with WB- DWI" : pregnant women with cancer and healthy subjects who required an imaging modality without contrast administration or ionizing radiation (Figure 4,5,6,7) 2. "One-stop-shop with WB- DWI" : comprehensive oncologic assessment in one sitting 3. "No dose with WB- DWI" : oncologic patients requiring serial follow-up imaging were evaluated by WB- DWI to limit the cumulative radiation dose. Images for this section: Page 4 of 18

5 Fig. 1: Maximum intensity projection (MIP) reconstructed WB-DWI. Page 5 of 18

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7 Fig. 2: Example of "problem-solving" in a patient with history of breast cancer and rising tumor markers. The PET-CT only shows FDG uptake in a metastatic left axillary lymph node (arrow). Page 7 of 18

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9 Fig. 3: The same patient in Fig. 2; WB-DWI showed multiple metastasis in lymph nodes (short arrows), bone (e.g. long arrows), and liver (arrowheads). Page 9 of 18

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11 Fig. 4: Example of WB-DWI follow-up in a pregnant woman with breast cancer considered as "only with WB-DWI". Metastasis in lymph node (short arrows) and bone (e.g. long arrows) are well-depicted on reconstructed image. Fig. 5: The same patient in Fig. 4; Metastasis in sacrum and iliac bone (long arrows) are seen on axial image; fetus brain is indicated by short arrow. Page 11 of 18

12 Fig. 6: The same patient in Fig. 4; Metastatic axillary lymph nodes (arrows) are noted on axial image Page 12 of 18

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14 Fig. 7: The same patient in Fig. 4; Resolution of metastasis after treatment. Page 14 of 18

15 Results A total of 329 WB-DWI were performed in our Institution from April 2009 to October WB-DWI exams were performed within the phase III melanoma study (4 in 2009, 22 in 2010, 57 in 2011, 45 in 2012 and 33 in 2013). 143 exams were performed in referred oncology patients and 25 in healthy subjects. Referrals (cancer patients and healthy subjects) grew from 1 in 2011, to 26 in 2012, and 141 in 2013 (Figure 8). Among the 143 referred oncologic patients, 55 were for staging, 63 for follow-up and 25 for problem solving. The main tumor histotypes were breast cancer (73), prostate cancer (20), myeloma (19), lymphoma (13), and melanoma (8). Among the 168 referrals (cancer patients and healthy subjects), 43 were considered "only with WB-DWI" (25 in healthy subjects and 18 in pregnant women with cancer), 94 "one-stop-shop with WB-DWI" and 31 "no dose with WB-DWI" (Figure 9,10). Images for this section: Fig. 8: Of the 329 WB-DWI exams performed between 2009 and 2013, 161 were performed within a clinical trial (phase III) in stage III melanoma patients (blue line) and 168 were performed in referrals (red line) with a sharp second year growth in the number (2012 vs. 2013). Page 15 of 18

16 Fig. 9: Graph illustrating the clinical setting for WB-DWI among the referrals (referred oncologic patients and healthy subjects) Fig. 10: Graph illustrating the histotype of the referred oncologic patients. Page 16 of 18

17 Conclusion Our results showed the increasing use of WB-DWI in our radiology department, suggesting an increasing acceptance of this exam among referring clinicians as a routine practice in an Oncology center. Personal information Giuseppe Petralia, M.D. Department of Radiology, European Institute of Oncology, Milan, Italy Giogio Conte, M.D. Department of Radiology, European Institute of Oncology, Milan, Italy Radiology Resident, University of Milan, Milan, Italy Seyed mehran Vaziri Bozorg, M.D. Department of Radiology, Imam Khomeini Hospital, Tehran University of Medical Sciences, Tehran, Iran Paul Summers, M.D. Department of Radiology, European Institute of Oncology, Milan, Italy Sara Alessi, M.D. Department of Radiology, European Institute of Oncology, Milan, Italy Massimo Bellomi, M.D. Department of Radiology, European Institute of Oncology, Milan, Italy Associate professor of Radiology, University of Milan, Milan, Italy Page 17 of 18

18 References 1. Padhani AR, Koh DM, Collins DJ. Whole-body diffusion-weighted MR imaging in cancer: current status and research directions. Radiology. 2011;261: Koh DM, Blackledge M, Padhani AR, et al. Whole-body diffusion-weighted MRI: tips, tricks, and pitfalls. AJR Am J Roentgenol. 2012;199: Petralia G, Padhani A, Summers P, et al. Whole-body diffusion-weighted imaging: is it all we need for detecting metastases in melanoma patients? Eur Radiol. 2013;23: Padhani AR, Gogbashian A. Bony metastases: assessing response to therapy with whole-body diffusion MRI. Cancer Imaging. 2011;11:S Gu J, Chan T, Zhang J, et al. Whole-body diffusion-weighted imaging: the added value to whole-body MRI at initial diagnosis of lymphoma. AJR Am J Roentgenol. 2011;197:W Page 18 of 18