Published online Jan 28, 2019. doi: 10.4329/wjr.v11.i1.10
Peer-review started: October 24, 2018
First decision: December 10, 2018
Revised: January 1, 2019
Accepted: January 10, 2019
Article in press: January 10, 2019
Published online: January 28, 2019
Recent developments and improvements in image acquisition and spatial resolution with multi-detector computed tomography has resulted in computed tomographic angiography (CTA) to become the first line-line investigation for upper limb pathology, replacing the more invasive digital subtraction angiography. It has the added capability of imaging the surrounding extravascular anatomy leading to the detection of incidental mass/lesions. The significance of these “incidental” findings has mixed opinions. Whilst evidence has shown them to identify potentially life-threatening pathologies, they can also lead to an unnecessary diagnostic cascade of investigations only for the end result to be benign. We set out to report the frequency and more importantly the clinical relevance of these incidental findings to better understand their significance.
We set out to establish the frequency of incidental findings and to follow-up to determine their end significance in upper limb CTA. This has yet to be been described in the literature. Incidental findings can lead to an unnecessary investigation cascade and therefore we wanted to determine the proportion of incidental findings which do lead to the diagnosis of a life-threatening pathology. This will raise awareness in the medical field of the importance for both the reporting radiologist and the referring physician of the need to recognise these findings and arrange appropriate follow-up. Evidence has shown cancer pathology is picked up through their detection and therefore highlights the importance of the reporting radiologist spending extra time to report structures outside of the scan indication.
Our objective was to report the frequency of incidental findings in CTA of the upper limb over a 2 year period. Those with findings of significance were followed up to determine their clinical outcome. We found incidental findings in over two thirds of patients, with 8.4% of them being of immediate clinical significance and detecting one index case of malignancy and four cases of new disseminated metastatic disease. Spending extra time reporting masses/lesions outside of the intended anatomy can significantly improve patient outcomes.
Consecutive upper limb CTAs performed at Guys and St Thomas hospitals between August 2015 to August 2017 were retrospectively reviewed for inclusion. Patient demographics, incidental findings and their follow-up were entered into an excel spreadsheet and statistical analysis was done using SPSS statistical software (SPSS, version 18.0 for Windows; SPSS Inc., Chicago, IL, United States). Incidental findings were grouped into category A (immediate), category B (indeterminate) or category C (no clinical significance). Conversely to other work in the literature, we retrospectively reviewed CTA reports rather than re-reviewing CTA images for incidental findings. This was to better reflect the current clinical practice as re-evaluation of images for incidental findings would theoretically increase their detection. Prior imaging studies were used as the standard of reference. Those with suspicious findings were followed to determine their significance.
A total of 153 extravascular incidental findings (EVIFs) were reported in 52 patients. Of these 13 EVIFs (8.4%) were Category A, 50 EVIFs (32.3%) were Category B, while 91 EVIFs (59.5%) were Category C. One index case of malignancy (1.3%) and four cases of new disseminated metastatic disease (5.4%) were identified. This is the first study to describe incidental findings in CTAs of the upper limbs. Detecting incidental findings can be of paramount importance however a large proportion also end of being benign. More work is needed in the recommendation of their follow-up and on cost-effective.
The purpose of this study was to report the frequency and more importantly the clinical relevance of extravascular lesions in patients undergoing upper limb CTA, including the frequency of index cases and progression of known cancer cases. We identified one index case of malignancy, and four cases of new disseminated metastatic disease. Our work shows the importance of detecting EVIFs. The early detection of cancer can be significant for patient outcomes and can ultimately reduce health costs by offering a curative surgical option. This may therefore, justify reporting and following up on incidental findings. To the best of our knowledge, this study is the first to evaluate for the presence of head and neck extravascular incidental findings on CTA of the upper limb. Nine EVIF were present in the head and neck, however, no category A EVIFs was identified. Although arterial phase CT imaging of the upper limb is a less commonly requested and performed peripheral arterial examination, both referring physicians and interpreting radiologists must recognize the frequency and relevance of incidental findings in this patient cohort allowing timely and appropriate clinical and imaging follow up. However, a cost-effective analysis of pursuing incidental findings in addition to long term studies comparing CTAs in vascular patients who did not have their extravascular findings reported needs to be conducted to adequately understand the true value of EVIFs. Attempts to provide guidance on the management of incidental findings have been made however data on cost-effectiveness is sparse.
Incidental findings are very common, and although most are of a benign nature, they do lead to the detection of serious life-threatening pathology which would otherwise be missed or diagnosed late. It is important for the reporting radiologist to be aware of their frequency to lead to their detection. More work is needed on guidelines for their management to aid in appropriate follow-up and to avoid an unnecessary cascade of investigations. Future work on their cost-effectives is needed and clinical outcomes to quantitively measure their importance. This can be completed in a long-term CTA study to assess if earlier detection of malignancy improves patient survival rates.