- The new probe
based on Raman spectroscopy can detect inflammatory bowel disease with
- The probe is
being designed to be used along with routine colonoscopy examination
conducted for patients with suspected inflammatory disease
- This device will
aid in detecting the inflammatory bowel disease better than existing
A sensor that can detect
inflammatory bowel disease (IBD), distinguishing between the two subtypes that
exist, will spearhead better care for patients soon. The device
is found to have greater sensitivity than currently used diagnostic methods.
The development of this device would help identify individual symptoms and
facilitate a more personalized care.
Inflammatory bowel disease
is a chronic inflammation of the bowel and it affects more than 1 million
people in the US and 2.5 million in Europe. The diagnostic procedures that are
currently available are based largely on trial and error and are not exact.
‘The new probe developed using Raman Spectroscopy can be used to detect Inflammatory Bowel Disease with greater specificity’
A pilot study reported
in the Journal Biomedical Optics Express,
includes details about a
specially designed endoscope that uses Raman spectroscopy, the technique used to observe
vibrational, rotational, and other low-frequency modes in a system
. The chemical-fingerprinting
technique helps identify molecular markers of IBD in the colon. This endoscope
is minimally invasive and can be included in a colonoscopy
Mahadevan-Jansen who is the senior author of the study and from The Vanderbilt
University, initiated the project after her tryst with IBD. "With current
methods, ultimately the diagnosis is dependent on how the patient responds to
therapy over time, and you often don't know the diagnosis until it's been a few
years. That's why we decided to use a light-based method to probe the biochemistry
of what's going on in the colon. Our goal is to use Raman spectroscopy to look
at the actual inflammatory signals."
There are two subtypes
- Ulcerative colitis : A chronic, inflammatory bowel disease that causes inflammation in
- innermost lining of the
large intestine (colon) and rectum.
- Crohn's disease : Inflammation
that occurs in any part of the gastrointestinal tract.
have similar symptoms and can lead to pain, fatigue, diarrhea, weight loss but
the two subtypes differ in their response to treatment.
The current method of
diagnosis involves the use of clinical, radiological as well as pathological
methods to identify the type of IBD but all these measures are used to detect
the symptoms rather than the subtype. The major drawback that nearly 15% of the
patients do not know their subtype while another 15% may be reclassified based
on how they react to treatment provided.
Studies that were
conducted earlier show that each of the subtype has a unique molecular
signature. The device that has been developed detects the signatures and the
inflammation state of the patients, providing a definite picture about the IBD
and the subtype.
added, "Most people go through baseline colonoscopy
as part of routine care, and you could imagine using this to get a baseline
Raman signal for each person. If someone presents with IBD symptoms later on,
you can use our system again to determine if it's more likely to be UC or
Crohn's. Then once they are being treated, you have an objective measure to
track their response because you can use the device to actually quantify mild,
moderate or severe inflammation."
Developing the Probe
The researchers used
samples of tissue as well as animal models to determine the initial biomarkers
and the spectral signatures that were associated with IBD. After which a small
portable Raman spectroscopy system was developed with a 785 nm diode
laser along with a fibre optic probe which could deliver 80 mW to the colon
Dr. Mahadevan-Jansen explained further,
"The customization was both the packaging - to make sure it can fit easily
in the endoscopy channel and bend through the turns of the colon - and to probe
the right depth in the tissues we are looking at to make sure we can get a robust
This is not
the first time that Raman spectroscopy has been used in medical applications,
earlier it was shown to detect cancer in the gastrointestinal tract. There was
a lot of subtlety involved in the use of this spectroscopy in the detection of
inflammation as there are only minor changes that are visible. The research
team involved in the study included special filters that removed the Raman
signature that were caused due to the use of the probe.
- Pilot Test
- The device was
used to detect inflammatory bowel disease in 15 patients with Crohn's
disease, 8 patients with Ulcerative colitis and 8 healthy volunteers.
- The results of
the study showed that the device had high sensitivity, which is the
ability to detect IBD but could not differentiate between the two
- Among patients
with active inflammation, the device detected Crohn's disease with
- 90% sensitivity
- 75% specificity
- Among patients
with all types of inflammation, the device detected Crohn's disease with
- 86% sensitivity
- 39% sensitivity
A set of algorithms are
currently being refines by the research team to facilitate easy understanding
for the doctors. Apart from that, greater specificity is being gathered by
understanding the gender, diet and demographic influence.
The device is very
useful in detecting IBD a lot more precisely than the currently available
diagnostic methods, aiding in better care.
- Isaac J. Pence, Dawn B. Beaulieu, Sara N. Horst, Xiaohong Bi, Alan J. Herline, David A. Schwartz, Anita Mahadevan-Jansen. Clinical characterization of in vivo inflammatory bowel disease with Raman spectroscopy. Biomedical Optics Express, (2017); 8 (2): 524 DOI: 10.1364/BOE.8.000524
What is Crohn's Disease? - (http://www.ccfa.org/what-are-crohns-and-colitis/what-is-crohns-disease/)