Last minute chest viva tips
You have put in months (years) of study and practice and it is almost time to sit the exams! Here are a few quick tips for polishing off those chest viva (and other) presentations.
Tumour, nodes, metastases
If you are in a case where you think you are diagnosing a malignancy - be it primary lung cancer, anterior mediastinal mass or soft tissue tumour - it is useful to break the case down into tumour, nodes and metastases. After all, it is exactly how you would structure your report in real life, Diagnose and describe the primary tumour, taking into account complications (for example downstream obstruction or vascular/bronchial invasion).
Then assess for lymph nodes, paying particular attention to the major stations in the thorax (mediastinum, hilum, supraclavicular and axillae). A useful trick for detecting mediastinal nodes on cut film is to follow the trachea down slice by slice, looking for right and left paratracheal nodes as you work down. When you get to the carina stop and look anterior for the pre-carinal node, then one or two slices down for the subcarinal node.
Commenting on metastases is easy to forget in the heat of the viva, but is a very important component of the case (as it is in real life). It is useful to consider what you think the primary tumour is and apply what you know to be the most common patterns of spread. For example, if you suspect a primary lung cancer - look for additional lung nodules, bone lesions and adrenal lesions in those upper abdominal slices. It is worthwhile telling the examiner you are doing this as you cast your eyes over these regions. If you are suspicious that you are dealing with a thymoma, remember to look for pleural deposits that suggest a more aggressive pattern of disease.
This approach also works for anything with a staging system, including lymphoma (nodes, liver & spleen, and extra-nodal disease) and trauma cases (where you work through organs, vascular structures, spaces and the skeleton). It is a useful fall back to add structure to your presentation, and ensure that you don't miss anything important.
There may not be a differential
Some cases (especially plain chest films) will have several differential diagnoses, as there is only so much definitive information you can confidently extract. But keep in mind that not every case in the chest viva (or any viva for that matter) will have multiple differentials. Many (most as was the case in my chest exam) will allow you to reach a single diagnosis. For this reason, don't feel that you always need to provide a differential list as it can muddy your performance and waste precious time. You don't want to come up with a differential which doesn't fit which brings your presentation of the case into question!
If you are feeling settled on a likely diagnosis, and you are stretching your brain to come up with more - just pause and think. You may have already reached the natural end of the case. Manage the patient and move on!
The flip side to this, is that some cases will reach a single diagnosis, but you may have to consider a couple of causes. A good example is oesophageal perforation. Depending on what you see in front of you and the clinical history, the cause may be Boerhaave's syndrome, iatrogenic perforation or a malignancy. You may have to consider all three.
Finding the right amount of detail
You have months and months of hard earned study under your belt and you want to show off the fruits of your labour. But just because you can, doesn't mean you should. It can be easy to start giving too much detail about your differential diagnosis and start describing pathology and histology in great depth. In some cases, it can be relevant (think cavitating metastases and squamous cell carcinoma), but launching into a spiel about the different histopathological subtypes of primary lung cancers is time consuming and unlikely to garner too many bonus marks. If you feel that some clinical detail will enhance your argument - go for it! That said, keep it high yield, relevant and brief. Then move on.
Let the cases speak to you
When preparing for vivas, we spend a lot of time working on structured presentations for 'exam favourites' and 'set pieces'. This is a valuable learning tool and can be very useful for having search patterns and differential diagnosis lists at the ready when you are under pressure. One thing to be aware of, especially for those of you who have finely honed your skills, is to be too quick to push a case into a 'set piece' box when it doesn't quite belong there. There might be a niggling feeling that there is something that doesn't quite fit with the presentation and diagnosis you want to offer. Also keep in mind that the exam is designed to challenge you, and most cases will have that extra element designed to test your acumen.
Although easier said than done, you have to be prepared to let the case speak to you. Don't rush into it. Take a moment to really look and get a feel for what you are seeing. Read the image as it is, keep an open mind and don't take for granted that it is going to be lifted from the pages of a textbook. You might miss the unique finding that makes the case!
Keep moving through the case
While impossible to do this in every case, the ideal approach is to keep moving forward without circling back on yourself. This means, if you get to a reasonable diagnosis, you don't want to circle back and re-describe the main finding. Or you don't want to jump around between findings, having to come back and address things a second or third time.
Let's use lung cancer as an example. When you identify the primary tumour, take time to describe it (morphology, relations/invasions, local complications). Tell your examiner that you favour a primary neoplastic lesion and are going to stage it - then work through nodes and metastases. At this stage, you don't want to go back and revisit the primary unless you have to (that is you have missed something important). You instead want to move onto management. And then you want to get that case down so you can tackle the next challenge!
If you are sitting your exams, your department already believes that you are good enough to function as an independent, mature radiologist. You have worked hard, have a well developed knowledge base and good instincts. Trust yourself. And if you can, pretend you have a microphone in your hand at your favourite reporting station. You've got this!