Tag: CT scan

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Evaluating The Pancreas On A Triple-Phase CT Scan Is A Minefield

triple-phase

I don’t know about you. But, for me, my least favorite CT scan has been the triple-phase CT scan to evaluate pancreatic masses. And, by most accounts in my group, many of our radiologists feel the same. For this reason, I would like to call the evaluation of the pancreas on a triple-phase CT scan a minefield. Many pitfalls in making the findings and interpretations abound. And no one, including the physicians and patients, is ever satisfied. But I thought this might be a good time to go through some of the issues you might encounter!

Subtle Lesions On A Triple-Phase

Pancreatic lesions tend to be some of the most subtle ones to detect. They can be hypovascular or hypervascular, infiltrative or circumscribed, versus cystic or solid. Sometimes, we see them in only one phase out of many in a triple-phase protocol. Even worse, you may only catch one of these lesions on a coronal or sagittal plane, which is not well confirmed by any other. You can miss one of these lesions in about a billion ways.

Severe Consequences For Missing A Lesion

Patient Tragedies

The lesions that you miss in the pancreas can be killers, literally. Both complex cystic and solid lesions can rapidly grow and kill the patient. I’ve seen significant changes over a few months or even less. Even worse, you can make the case that the patient would have significantly fewer complications if you had caught it earlier. These complications can include more extensive surgery, more potent chemotherapy with its consequences, or broader radiation treatment plans for palliative care. And the list goes on and on.

Legal Tragedies

Also, with the potential patient tragedies for missing lesions comes the potential for malpractice lawsuits in the “retrospectoscope.” Judges and juries can easily mistake “not-so-subtle” pancreatic lesions for prospectively discovered subtle ones. Along with the possibility of doing significant harm to patients for missing findings, this discrepancy can cause high-cost malpractice lawsuits/claims. If you read enough of these studies, it is only a matter of time before you receive one!

Numerous Additional Findings

In addition to the problem of finding the primary lesion, many different additional findings can change a patient’s management dramatically. These findings can also be very subtle. I’ve seen numerous permutations and combinations of various venous and arterial thromboses that folks always miss. Then, there is a debate about whether a lesion surrounds a vessel and to what extent. This issue necessarily affects whether or not one gets surgery. And I can’t tell you how often that outcome can differ depending on who is reading the study. Of course, you also have subtle lymph nodes with the porta adjacent to the head of the pancreas and within the celiac axis. All these different additional findings that you have to think about can make your head spin. And the consequences of missing them are dire!

Angry Surgeons

Finally, you must contend with the people who ultimately ordered the study. These tend to be the busiest of surgeons. And for that reason, the word “ornery” almost does not do justice. These folks are often on the edge of burnout from overworking and complex patients. They have their requirements for the reader they want and how they want their studies. You will notice at your institution that they might call a study for this surgeon a Dr. “John Doe” protocol because every surgeon wants the triple-phase protocol done slightly differently.

The Triple-Phase Protocol For The Pancreas Is A Minefield!

As you can see, when you find one of these studies coming through your department, batten down the hatches and do not let your attention stray. Making the findings can be challenging, and there are potentially “oh” so many of them. Remember to look at all the images and phases. And make sure to relay all the information neatly and logically. The triple-phase protocol for the pancreas is not for the faint of heart. It’s a veritable minefield of potential misses and problems!

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Don’t Forget About The CT Reconstructions!

CT reconstructions

Due to improving CT scanner and software technology, the resolution and detail of reconstructions have dramatically improved over the past ten years. Nowadays, most institutions include these CT reconstructions in their protocols without even an afterthought. However, it wasn’t always like that.  And, like most other images from a CT exam that we add onto PACs, these images exist for a good reason.

But, with the increasing numbers of slices, it has become more common to forget about them. And, that’s understandable. It takes extra time to look at so many additional images. So, let’s go through why it’s worth our time to give them a well-deserved second look and why you should not interpret a case without them.

Some Structures You Can Only See In Another Plane

Ever go through a CT scan and search for the appendix? Especially in folks with a lot of intra-abdominal fat, they pop up in seconds. But, in the typical thin child with lots of contrast filled bowel and not much fat, the abdominal axial images do not help all that much. It is the magic of the coronal plane that often lets you see the appendix in all of its glory.

And, it is not just the appendix. I have seen renal tumors with barely a contour defect at all on the axial images. But, when you look at the coronals, they become readily apparent.

What else? Well, compression fracture deformities magically appear on the sagittal images, sometimes without a hint of abnormality on the axials. So, make sure to use these reconstructions wisely!

Increased Conspicuity

And, it’s not just that you can only see some structures on individual planes. Other times, it just becomes a whole heck of a lot easier to make the findings. Take the bowel, for instance. If you go back to one of my cases from May 25, 2019, you can find a colon cancer that was exceedingly hard to pick up on the original axial images. However, on the coronal images, it becomes a bit more reasonable to find. And, this holds for many other organs as well. Liver lesions, lung nodules, and fractures are other examples of findings that can sometimes be much easier to detect in different planes.

You May Miss The True Consequence Of The Finding

On the axial images alone, you can interpret the findings in the wrong way. Take a look at a typical CT scan. Many times diffuse ground-glass opacities on axial images can look entirely linear on a coronal or sagittal. And, that makes an enormous difference in the final interpretation. Linear opacities on a chest CT are not clinically relevant.  On the other hand, diffuse ground-glass opacities may mean pneumonia, invoking antibiotics and a call to the doctor to return.

Or, you can easily misinterpret disc disease if you look at it in the wrong plane. I can’t tell you how many times I have seen neural foraminal stenosis that disappears once you look at the right sagittal or reconstructed axial planes.  It pays to take another gander at these recons!

CT Reconstructions- Not Just Another Useless Set Of Images!

Unfortunately, reading additional images adds more time to the radiologist’s workday. But, the rewards for reading CT reconstruction series and penalties for missing findings without using them are enormous. So, the next time you see another sequence of reconstructions, do not brush them off as just another set of useless images. Instead, make these reconstructions a regular part of your search pattern for any CT scan study that you read. First of all, you will know to ask for them when they are missing. And finally, you will be glad that you did!