Patients with a strong suspicion of small bowel's CD after the colonoscopy and laboratory
studies will be recruited to study protocol in the outpatient gastroenterology clinic of
Turku University Hospital. After the signed informed consent patients will undergo
combined [68Ga]Ga-DOTA-Siglec-9 and [15O]H2O PET/MRE, the MRE being part of their
clinical diagnostics. If the MRE shows no signs/or mild inflammation of small intestine
CD patients will be directed to small bowel capsule endoscopy (SBCE), which is routine in
this clinical suspicion.
The patients will also have routine blood samples taken. A complete blood count (CBC),
C-reactive protein (CRP), creatinine, alanine aminotransferase (ALAT), alkaline
phosphatase (AFOS) and albumin will be analysed from each patient's blood sample,
calprotectin and faecal microbiota will be analysed from stool. The tissue samples for
(immuno)histological evaluation, proteome-wide mass spectrometry allowing sensitive
site-specific detection of ADP-ribosylation and structural protein analysis will also be
obtained in primary ileocolonoscopy (biopsies from the bowel wall).
Before the PET study starts, the patients will undergo screening procedures with physical
examination, chemistry panel (electrolytes, creatinine, liver function), and acute phase
reactants (ESR, CRP) and urine tests. In addition, serum/plasma biomarker sample, serum
sample for soluble VAP-1 analysis, whole blood RNA sample, and whole blood DNA sample for
gene variant analyses will be collected.
In the combined PET/MRE scanning the study subjects lay in the prone position on the PET
scanner bed, and the area of interest (AOI) is positioned in the gantry and in the field
of view.
[68Ga]Ga-DOTA-Siglec-9 and [15O]H2O PET/MRE imaging will be performed in the fasting
state (at least 6 hours). The patients will be instructed to avoid caffeinated drinks
during the last 24-hours before the study. A catheter will be inserted in an antecubital
vein for injection of PET radiopharmaceutical. Another catheter will be inserted in the
opposite radial or antecubital vein for blood sampling and the subjects will be placed in
supine position in the PET/MRE scanner, arms next to the body. Ideally, urinary bladder
should be empty before PET/MRE scan. The uptake of tracer will be measured using PET and
MRE will be performed for anatomical reference.
After PET scans, the patients with CD will be treated and followed by gastroenterologist
according to the current guidelines.