Principles of reporting. Barium enema interpretation. Challenging cases: How not to sit on the fence! Medicolegal basis

Transcription

1 ADVANCED PRACTICE IN GASTROINTESTINAL IMAGING Barium enema interpretation Challenging cases: How not to sit on the fence! Gary Culpan Lecturer in Radiography, University of Bradford Principles of reporting Medicolegal basis Practical skills Structure of a report Make a decision Answer the clinical question Influence patient management Scheme of work Medicolegal basis Outline what is undertaken Reporting policy / protocol Trust board Radiology manager Staff providing service Professional body guidance SCoR HPC RCR GMC 1

2 Practical skills Post Graduate courses Radiographic anatomy Normal and variant Pattern recognition Range of pathology Full range of pathologies which can affect the large bowel Radiographic appearances of pathology Diagnostic features Clarity of margins of abnormality Assessment of mucosa Terminology / Communication Range Descriptive Technical Understandable Structure of a report Guidelines from RCR 1 and ACR 2 1. Board of the Faculty of Clinical Radiology, The Royal College of Radiologists (2006), Standards for the reporting and interpretation of imaging investigations. Royal College of Radiologists, London. 2. American College of Radiologists: Standard for Communication in General Diagnostic Radiology (2005) Practical example Patient / examination / institution details Clinical history / question Description / discussion of findings Diagnostic features Differential diagnosis Most likely to least likely Recommendation for further imaging Conclusion 2

3 Make a decision Errors in decision making Report without a decision may render the examination worthless Technical inadequacy of the examination Patient is subjected to further invasive tests Colonoscopy, Computed Tomography, follow up Barium Enema Degree of certainty clearly indicated Don t t know is sometimes the right answer What is needed to ascertain the diagnosis? Clinical examination laboratory tests imaging invasive tests Irrationality Availability error Primacy error Halo effect Obedience Conformity Consistency Ignoring / distorting the evidence Wrong judgements Misinterpretation of the evidence Overconfidence False inferences Sutherland S. (1992) Irrationality: The Enemy Within Constable & Co. London Errors in decision making Availability error This is judging an issue by the first thing that comes to mind Example 1 Are there more words in the dictionary beginning with R or with R as the third letter? Our perception is coloured by the fact that dictionaries are sorted in alphabetical order so we immediately think that there are more starting with R when in fact there are more with R as a third letter Example 2 The film JAWS caused a sharp drop in the number of people prepared to swim off the coast of California where the occasional shark is seen. However, in reality the risk of being killed in an accident on the way to the beach is much greater than the chance of being attacked by a shark! More examples If you are driving along the road and pass an accident do you: Slow down because you think that you might also be involved in an accident? Carry on regardless? Can you explain your answer What if you are speeding and see a police car travelling in the opposite direction? Do you slow down? Can you explain your answer? 3

4 More examples Which is more probable? 1. A girl with blue eyes has a mother with blue eyes 2. A mother with blue eyes has a daughter with blue eyes Over 75% of people asked this question instinctively think that cause produces effect and so answer 2 More examples In medicine it is well recognised that doctors who have recently seen a number of cases of a specific disease are more prone to diagnose it in patients who do not have the disease Radiographers also fall into such traps. I I saw one like that last week and it was. without rationalising the images Answer the clinical question If your findings are unrelated to the clinical question are they relevant? The unexpected finding How urgent? Document verbal communications Have specific protocols in place Influence patient management Need to have a good idea what the management will be in order to influence it If you are unable to distinguish faecal remnant from true pathology what happens next? Limited exclusion value What does it mean? 4

5 Practical experience Review of specific images from real cases How easy is it to make the decision? Anatomical variant What are the limitations? 72 year old male with alternating constipation and diarrhoea with excessive flatus. Iron deficiency anaemia, upper GI endoscopy arranged. FOS limited by diverticulosis. Exclude significant pathology Analyse the image No mass lesion or stricture 5

6 Obstruction to retrograde flow of barium and air Analyse the pattern in the ascending colon N o evidence of appendix, terminal ileum, ileo-caecal valve Abnormal mucosal contour This shows the distal edge of an obstructing carcinoma Multiple filling defects Polypoid 51 year old male with rectal bleeding. Flexible sigmoidoscopy NAD On non-dependent surface Endoscopy missed them 6

7 79 year old male with change in bowel habit and weight loss Long stricture in sigmoid Mucosa is destroyed at distal end of stricture Both ends of stricture are tapered Mucosa is preserved at proximal end of stricture Diverticular necks visible Rationalise the findings Is this a benign or a malignant stricture? Features of both Perforated tumour may produce this image pattern Clinical history influences decision that tumour likely Confirmation required CT will reveal extra luminal pathology Endoscopy and biopsy determine tissue type 7

8 Comparison inflammatory stricture Stretched diverticular necks Malignant stricture Relatively short and tight Destroyed mucosa Complicated mucosal pattern No mass effect Shouldering 76 year old female with change in bowel habit to constipation. Iron deficiency anaemia noted Loss of haustral folds at hepatic flexure Trace edge of lesion 8

9 Profile view hepatic flexure Destroyed mucosa 88 year old male with iron deficiency anaemia Trace outline of lesion Review caecum Target sign Irregular filling defect Pedunculated polyp 69 year old female with iron deficiency anaemia Villous tumour Other views clear the hepatic flexure Unexplained soft tissue density sigmoid descending colon junction 9

10 Close up of suspicious area Diverticula are evident Analysis Overlap lateral margin transverse colon Analyse soft tissue density Must lie in descending colon Associated smaller polyp? 56 year old male with blood and mucus noticed on toilet paper Filling defects noted Bubbles can be ignored Faecal? Trace the outline of the bowel Mucosal coating stops 10

11 Rectal lesion Poor coating Irregular surface Villous tumour 85 year old female with change in bowel habit. Gas filled viscus Stretched diverticular neck Mass effect Diverticulosis 58 year old male with change in bowel habit Does the rectum look odd? Giant sigmoid diverticulum 11

12 Oblique images helpful? Review the lateral rectum Review findings Rectum is elongated and stretched Mucosa is intact There is some pleating of the rectal mucosa This is extrinsic compression What pathology can we relate this to? Review the clinical history This man was an overweight Afro-Caribbean male He was also under investigation by urologists for urinary retention and had previously had a TURP Doesn t t fit with enlarged bladder impression Review of the case makes pelvic lipomatosis the most plausible diagnosis Levine, Rubesin & Laufer (2000) p

13 Discussion The expert reporting practitioner homes in on a relatively few but highly specific features of the image to determine normal from abnormal This process occurs subconsciously but the final diagnosis is tempered by conscious deliberation This allows the differential diagnosis list to be short The expert reporting practitioner also is able to remember key features of individual cases and associated diagnoses Aunt Minnies Specific features of the clinical history will guide the conscious reasoning The Novice reporting practitioner Build upon early pattern recognition skills Enhance knowledge of normal and abnormal patterns Apply a directed search pattern Utilise deductive reasoning to determine the differential diagnosis list Relate clinical history to imaging findings Positively influence patient management Use of stock phrases help or hindrance? Barium flowed to the caecum. The whole of the large bowel is shown in double contrast Barium refluxed into a normal terminal ileum The caecum is adversely affected by poor coating due to retained colonic fluid There is faecal residue within the caecum and ascending colon Due to sigmoid diverticulosis, polypoid lesions cannot be excluded in this segment Thank you for listening 13

14 60 year old male with 2 year history of intermittent diarrhoea. Recently mucus and small amount of blood Classic appearances of UC 36 year old male with intermittent diarrhoea. Acute episode with associated severe pain. Rectosigmoid shows apthous ulceration Cobblestone pattern Collar stud ulcers in descending colon Discontinuous and asymmetrical 14