“Please correlate clinically.” “Clinical correlation is recommended.”
What is “clinical correlation” and what do these words signify when a radiologist includes them in their report?
This blog post will explore the meaning of clinical correlation and its importance when reading a radiology report for both healthcare providers and patients.
What is Clinical Correlation?
“Clinical correlation” is a term used in medicine, frequently within radiology reports, that can and should be taken literally – correlate the abnormal or unexpected imaging finding with what’s going on with the patient clinically.
Healthcare providers should use the patient’s clinical findings (medical history, physical exam, laboratory testing, other imaging studies, etc.) to determine the significance of the radiology findings. A patient’s clinical history is essentially medicine’s Rosetta Stone for deciphering unexplained imaging results.
In other words, look at all of the information available and see how the unexpected finding(s) correlate(s) to that specific individual.
The goal is to narrow down a differential diagnosis (the potential causes) to one accurate diagnosis that can account for all of the patient’s symptoms (i.e., identify the disease process that can explain the cause of the underlying medical illness or problem) and rule out other potential diagnoses mentioned in the radiologist’s interpretation.
For example, we may say “‘A’ is present and could be secondary to ‘X, Y, or Z.’ Correlate clinically.” This is our way of saying that we found something abnormal (‘A’ in this case) but have inadequate clinical information to differentiate between ‘X, Y, and Z’ as the cause of ‘A’ and we’re asking the ordering doctor/provider to fill in the gaps and narrow it down to the most likely underlying cause.
While there are occasional memes with healthcare workers jokingly suggesting radiologists overuse the phrase (at least I hope they’re joking!), clinical correlation plays an incredibly important part to providing excellent patient care and is where the radiologist fits into the medical team.
Why is it Important for Doctors to Correlate Clinically?
Clinical correlation is a critical part of being a great doctor. Think of yourself as a detective. You have to be able to look at a patient, take in all of the information available to create a full picture of what’s going on, and put the pieces together in a way that solves the puzzle.
Keep in mind: Occam’s razor (the simplest solution is likely correct – a single etiology is most likely the lone cause) versus Hickam’s dictum (a patient can have as many diseases as they darn well please – more than one underlying pathology may account for the patient’s illness).
Every patient is unique, so healthcare providers must take all of the patient’s specific medical information into account to figure out the significance, if any, of the abnormality discovered on the imaging exam. Providers need to take a step back from the trees and see the forest. Look at each test result individually and the test results as a whole (e.g., T3 and T4 levels are much more useful when you have a TSH).
Clinical correlation is important because it allows doctors to make an accurate diagnosis using all the information available to them. By correlating clinical data with laboratory test results, imaging findings, and other information, doctors can obtain the correct diagnosis that will guide management and ensure that their patients receive the appropriate care they deserve.
Treat the patient, not just abnormal imaging or laboratory results!
How is Clinical Correlation Used in Practice?
Clinical information and data are collected and analyzed to identify existing patterns or relationships that may account for the abnormality in question. Then the scientific method plays out. The collected information is used to generate a clinical hypothesis that can then be tested to prove or disprove the hypothesis or at least set the doctor on the correct path. They ask additional questions, order another test, etc. until the problem can be narrowed down to the root cause.
Successfully correlating the laboratory test results and imaging findings with the patient’s clinical situation and physical exam helps to improve the accuracy of the clinical diagnosis and ensure the patient receives the appropriate treatment. After all, this is why doctors and healthcare providers went into medicine in the first place – to deliver amazing care to patients!
One of the key benefits of clinical correlation is that it helps to ensure that clinical decisions are based on the analysis of evidence. By analyzing clinical data, acquiring more data when relevant, and identifying any patterns or relationships that may exist, clinicians can make better-informed decisions and provide better care to their patients. More accurate diagnoses lead to better patient outcomes.
Clinical Correlation for the Patient
“I’m a patient and my radiology report says ‘correlate clinically.’ What does this mean for me?”
Great question. Our radiology reports are generally full of medical jargon and intended for the ordering doctor/mid-level provider to read and understand. We have become aware that patients now have access to their radiology reports through online portals, which can be very confusing to someone not in the medical field.
As radiologists, we use the words “correlate clinically” in our reports when we’re not sure of the significance of a certain finding (what we see in the radiology exams we interpret).
Sometimes there are several possible explanations for the findings we’ve identified on the images based on the clinical history we’ve been provided, which can unfortunately be quite limited or even non-existent. As radiologists, our focus is on evaluating images as accurately and efficiently as possible. But we frequently find ourselves with limited access to further information and limited time to spend searching for information without delaying the care of other patients.
This is when we’ll ask your healthcare provider to “correlate clinically” to make the correct diagnosis based on everything they know about you, your symptoms, and any underlying medical conditions you may have.
Also, good for you for looking out for yourself and stumbling across this article! As doctors, we do our best to help our patients and we do a much better job when we’re able to work together with our patients. So kudos to you for taking an active interest in your health!
Clinical Correlation for the Referring Provider
A referring provider can be either a doctor, physician assistant (PA-C), or nurse practitioner (ARNP).
While I can’t speak for all radiologists, I personally (as well as most of my radiology colleagues) have different expectations for generalists and specialists and try to help guide management in a way that I (we) think is most appropriate for each patient based on this context.
For common incidental findings, such as an incidental pulmonary nodule, I simply use a macro containing evidence-based recommendations from important articles such as the Fleischner Society Guidelines for Managing Incidental Pulmonary Nodules (the article I defer to for incidental pulmonary nodule follow-up) or an American College of Radiology (ACR) white paper (articles written by experts within the corresponding radiology subspecialty for a variety of incidental findings). I know a typical healthcare provider will know how to risk stratify a patient for likelihood of lung cancer (do they have a significant smoking history?).
Another common example is when we struggle to differentiate pathologic bowel or bladder wall thickening from underdistention, both of which can look similarly thick-walled. Both entities can have a similar appearance and only the presence of symptoms or test results (e.g., urinalysis) can help differentiate between the two.
For less common incidental findings, we try to help guide providers with what next steps may be necessary and will frequently suggest which specialty to consult.
For example, when we see a new suspicious renal or bladder mass, we’ll frequently suggest or recommend a urology consultation since a urologist is most appropriate to manage this patient. If we see evidence of metastases, we may also recommend an oncology consultation since that patient will likely require systemic therapy.
(Personal Opinion: We should be calling you or having support staff leave a message as well – we’d hate to see something like this fall through the cracks!)
Clinical Correlation for the Specialist
In medicine, a specialist is a doctor who is specialized in a particular area of medicine.
For specialists, we change our verbiage accordingly. For example, interstitial lung disease (ILD) consists of a spectrum of disease processes that I would not expect general clinicians to have a thorough knowledge of. I would recommend a pulmonology consultation to work-up newly discovered ILD when the imaging examination is ordered by a general practitioner.
However, when the exam is ordered by a pulmonologist, I expect the pulmonologist to understand my interpretation and know what to correlate for (e.g., does the patient have a history of bird exposure, a prior smoking history, etc. that will help narrow the differential diagnosis). The pulmonologist will also determine if any procedures are necessary such as bronchoalveolar lavage (BAL) or biopsy.
Another example is what to do when we incidentally find pneumatosis (gas within the bowel wall) as it can be benign in asymptomatic individuals or secondary to life-threatening bowel ischemia when severe pain is present. We expect an emergency medicine physician to check for abdominal pain and consult a general surgeon to see if surgery is necessary.
What Are Some Examples of Physical Exam Findings?
One of the most common physical exam findings we often ask for correlation for is point tenderness. “There’s a questionable fracture of the {insert bone of your choice here}, recommend correlation for point tenderness.”
As radiologists, one of our biggest limitations, especially in the setting of a vague history such as “pain,” is our inability to directly assess the patient.
Questionable lung opacity? Auscultate the lungs a little closer. Borderline gallbladder wall thickening on ultrasound, CT, or MRI? Push on the right upper quadrant to assess for tenderness or a Murphy sign.
Why Does a Radiology Report Recommend Clinical Correlation?
Simply put, we use this phrase when we don’t have an adequate clinical picture and/or the findings are inconclusive.
We will frequently call things “nonspecific,” which means it is not specific to any one entity, and narrowing down the underlying pathology can only be assessed clinically.
An example: fluid (edema), pus (pneumonia), and blood (hemorrhage) all overlap in their appearances on x-ray and CT. If the person has a fever, it’s probably pneumonia. If they have leg swelling and a history of congestive heart failure, it’s probably pulmonary edema.
More relevant medical information is needed to help explain the findings on the patient’s imaging examination which typically requires either asking patients more questions or further testing.
As mentioned above, we typically defer to “clinical correlation is recommended” when there are a few differential considerations that only the doctor/provider can decide between by looking at the individual patient inclusive of their symptoms and any existing test results.
…But Shouldn’t the Radiologist Be Able to Determine Everything from Imaging?
Oh, if only we had a crystal ball…
While we are skilled at interpreting images and can often make a diagnosis from an image alone, that isn’t always the case. We want to give answers, but we don’t want to provide wrong or incorrect answers.
“Clinical Correlation Recommended” Examples
X-ray:
- Interstitial opacity on chest radiographs → Does the patient look infected or have congestive heart failure? Pulmonary edema, atypical infection, and ILD can all be interstitial processes.
- Subtle or questionable cortical irregularity on any bone → Check for point tenderness. A prominent nutrient foramen, overlapping structures, and sometimes just the position of the bones can look like a fracture.
CT:
- Pneumatosis → Are there signs or symptoms of bowel ischemia? There are a lot of causes of benign pneumatosis while bowel ischemia would require emergent surgery to save the bowel. Calling all pneumatosis malignant would be far worse and result in unnecessary surgeries.
- Questionable bowel wall thickening or bladder wall thickening → Are there signs of infection or could the wall thickening simply be due to underdistention?
- New focal low-attenuation on a head CT → Are there stroke-like symptoms? Further testing with MRI may be warranted.
MRI:
- Meningeal enhancement mentioned on a brain MRI report → Does the patient have a known malignancy or signs of infection?
- Probable adenomas within the liver → Is the patient currently taking birth control? This can cause adenomas to persist or even grow. Adenomas can bleed and cause pain.
Ultrasound:
- Gallbladder wall thickening in a patient with ascites or liver disease → Is it reactive? Third-spacing? Acute cholecystitis? They can all look the same on imaging.
- Extrahepatic biliary ductal dilatation → Is it due to the post cholecystectomy state, an obstructing mass, or obstructing bile duct stone? The presence of pain, jaundice, and bilirubin levels will help.
Nuclear Medicine:
- Radiotracer uptake on a bone scan in a pattern not consistent with metastatic disease → Is there a recent history of trauma (healing fracture) or an underlying metabolic bone disorder to account for the atypical abnormal uptake?
Summary
“Clinically correlate” is the radiologists’ way of contributing to patient management and indirectly acting as part of a patient’s clinical care team.
As radiologists, we make abnormal and potentially abnormal findings all the time, but frequently the imaging findings alone are not sufficient to make a definitive diagnosis. It is here where we rely on a patient’s clinician to further whittle down the differential diagnosis and determine what best fits with the patient’s clinical picture.
When we ask the referring doctor to “correlate clinically,” we’re asking for help with our main limitation: lack of access to the patient and sometimes their medical record.
So ordering providers, you are the Sherlock Holmes, detective extraordinaire, to our Watson.