Prevalence and significance of hypoattenuating hepatic lesions deemed too small to characterise: How are we following up these lesions and what are the outcomes? Poster No.: C-014 Congress: ECR 2009 Type: Scientific Exhibit Topic: Abdominal and Gastrointestinal Authors: G. M. Jonathan Albuquerque, H. Khosa, P. McCarthy; Galway/IE Keywords: Abdomen, Liver lesions, hepatic lesions too small to characterise DOI: 10.1594/ecr2009/C-014 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. www.myesr.org Page 1 of 11
Purpose To retrospectively determine the prevalence and significance of small hypoattenuating hepatic lesions discovered at Computed tomography. To determine the frequency with which they represent clinically important findings. To present our present follow-up of these lesions. Methods and Materials The authors retrospectively reviewed 1192 CT scans and reports of patients undergoing CT thorax, abdomen and pelvis scans, from 2005-2007. The initial and final CT scans were reviewed for hypoattenuating lesions less than 15mm, that were reported as too small to characterise (TSTC). The primary diagnosis, treatment, number and size of lesions and their interval change were also reported. Any additional investigations, such as ultrasound and MRI and their findings were documented. Inclusion criteria: Patients with multiple CT scans. Patients with long term follow-up. Patients with 1 or more hypoattenuating lesions that were deemed to bo non-specific or too small to characterise (TSTC) on the initial scan, by the reporting radiologist, ie <15mm in size. Exclusion criteria: Patients with short term follow-up of less than 12 weeks. Patients with non contrast CT. Patients with single scans. Patients with lesions characterised on the initial CT, as either cysts, netastases or haemangiomas. The CT scans were performed at the Univeristy College Hospital of Galway Radiology CT department. Two scanners were used during this period, with differing scan protocols. The majority of patients were scanned with an 8 mm slice thickness. There were 32 CT scans performed with 5mm thickness and collimation of 4mm for thorax and 5mm for abdomen.scanning was done after a monophasic injection of 100ml of contrast. Only a few of the finak scans after October 2007 was performed on a 64-slice sscanner. Results Page 2 of 11
STUDY RESULTS Of 1192 CT scans, 564 (47%) patients had multiple contrasted scans. Of 564 patients, 96 (17%) patients had lesions deemed TSTC. 6 (6.3%) of the 96 patients were excluded due to a short scan interval of 12 weeks. Follow-up imaging of 90 (15.9%) patients revealed lesions were: unchanged in 71(78.9%), increased size in 5 (5.6%), decreased in 3 (3.3%), and not seen in 9 (10%). 2 (2.2%) patients with multiple lesions, each had 1 lesion unchanged with the rest either decreasing in size or not visualised. Page 3 of 11
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The 5 enlarging lesions, represented metastatic breast cancer in 3 (3.3%). A dilated hepatic duct in 1 patient. Simple cyst in 1 patient (1.1%). Of the 90 patients, there were 41(46%) males and 49(54%) females. Mean follow-up interval of 464.5 days, with a range of 103-1027 days. This is equivalent to a follow-up of 66.4 weeks, with a range of 15-147 weeks. Page 6 of 11
Out of the 90 patients, only 2 were scanned without a primary diagnosis of a malignancy. There was a wide range of primary malignancies present, with breast cancer being most prevalent within our population group. See graph below. The patients' treatment regimes were documented and ranged from chemotherapy only, chemotherapy and surgery, or chemotherapy and radiotherapy, etc. Please see related graph below. Page 7 of 11
The majority of patients had a solitary lesion (48), though several patients had 2-4 lesions (30) and >=5 lesions (12). Page 8 of 11
The sizes of the 180 lesions were divided into 0-5mm, 5-10mm and 10-15mm. Most lesions were less than 10mm (159/180). Only 21 lesions were more than 10mm (21/180). See graph below. Page 9 of 11
PATIENTS WITH ULTRASOUND 23 patients had ultrasound to further evaluate the lesions seen on CT. In 16 patients, the lesions were not detected. In 7 patients, the lesions were proven to be cystic, this included the patient with the enlarging cyst. PATIENTS WITH MRI 10 patients underwent MRI. 5 of these confirmed hepatic cysts. 4 lesions were not visualised and 1 lesion was demonstrated to be a haemangioma. MRI detected additional findings such as haemangiomas in 2 patients. STATISTICS The observed p value for unchanged lesions is 0.40884. The stated p value is 0.05. The observed value is greater than the stated hence we accept the null hypothesis with 95% confidence that the unchanged lesionsare either are non malignant or responding to chemotherapy. Statostical Difference between males and females: The data was fed into SPSS and the P value calculated. The claculated P value is 0.05 so we can say with 95% confidence that there were more non-specific hepatic lesions in females in males. Page 10 of 11
Significance between liver lesions in patients on chemotherapy and other treatments: The data was fed into SPSS and T value calculated. There was no significant difference between the 2 groups. Significance of liver lesions and 3 main cancer types in the study: The data was fed into SPSS. The patients with colonic cancers had slightly more hepatic lesions with a p value of 0.09. Although breast cancer is the commonest cancer in the study, patients with colonic cancers were the group with slightly higher prevalence of liver lesions as shown by the p value. Conclusion CONCLUSION The prevalence of small hepatic lesions in our study is 15.9% with 3.3% of these proving to be metastatic breast cancer. Additional imaging of these lesions with US and MRI did not assist in characterising the lesions in 69.9% and 40%, respectively of the cases imaged. Compared to previous studies, our findings are similar: Khalil et al, Radiology 2005-29.4% prevalence with 92.7-96.9% being benign. Schawrtz et al, gastrointestinal Imaging 1999-12.7% prevalence with 88.4% being benign. Krakora et al, Radiology 2004-35% prevalence with no relation to subsequent development of hepatic metastases. Follow-up CT is the best imagaing modality, but the interval for follow-up remains controversial. Our study is small and a definite time interval cannot be determined. 2 out of the 3 metastatic lesions showed interval change at as early as 5 months (mean follow-up 18 months). Yet, we have to recognise the slow-growing or stable metastases with stable CT follow-up at 6 months (Jones et al, 1992). STUDY LIMITATIONS Retrospective review. Criteria for stable lesions was no increase in size. Technique used for CT TAP is outdated - more lesions may have been yielded with the ise of multidetector CT with multiplanar reconstructions. No histological diagnosis of lesions. Page 11 of 11