A feasibility study to suppress myocardial [18F]-FDG uptake by pre-administration of pure caffeine

[18F]FDG PET/CT has an increasingly relevant role in diagnosis and treatment
management of cardiac inflammation and infection imaging. Cells involved in the
inflammatory process have an increased glucose consumption and accompanying
[18F]FDG uptake. Physiological [18F]FDG uptake occurs also in the normal
myocardium. This uptake can be reduced by dietary manipulation, extended
fasting and intravenous heparin before the administration of [18F]FDG.
Although, administration of heparin carries a risk of heparin induced
thrombocytopenia and bleeding. A safer alternative to stimulate free fatty acid
levels and lipolysis is administration of caffeine anhydrous. This approach
have never been tested for [18F]FDG PET/CT. Therefore, this pilot study will
investigate the tolerability and effect of pure cafeine food supplement on
myocardial [18F]FDG uptake suppression.

To investigate the tolerability and effect of pure cafeine food suplement
pre-administration on myocardial [18F]FDG uptake suppression.

This pilot study will compare the myocardial [18F]FDG uptake suppression
between a study PET/CT with the standard carbohydrate restricted diet and a
food supplement containing 200 mg pure caffeine one hour before [18F]FDG
injection and the inadequate routine PET/CT prepared with standard carbohydrate
restricted diet.

The patients will receive one hour before the [18F]FDG injection a tablet with
200 mg of the food supplement pure caffeine.

- In this study 10 adult patients with inadequate myocardial [18F]FDG
suppression on their routine [18F]FDG PET/CT, despite correctly fulfilling of
the carbohydrate restricted diet.
- Patients will be asked to keep a record of the food and drinks they had
during the 24 hours before the appointment.
- Patients will be asked to drink only water instead of water, coffee and thee
during the two hours before the appointment.
- Patients will receive a 200 mg tablet of pure caffeine food supplement one
hour before [18F]FDG injection..
- Heart rate and blood pressure wil be measured before caffeine, before
[18F]FDG and after PET/CT. If SBP>150 and DBP.90 before administration of the
caffeine, the patient will be excluded.
- For blood glucose comparison an extra blood sample will be taken before
taking the caffeine tablet out of the venous cannula that will be placed for
the [18F]FDG administration.
- For FFA comparison extra blood samples will be taken before caffeine and
[18F]FDG out of the venous cannula.
- Patients will be asked to fill in a questionnaire concerning symptoms and
mood before caffeine, before [18F]FDG and after PET/CT.
- According to the European Food Safety Authority (EFSA) will a single dose of
caffeine up to 200 mg do not give rise to safety concerns for the general
healthy adult population.
-Expected side effect of 200 mg caffeine intake is:
Slightly increase of blood pressure (systolic blood pressure 3-8 mmHg,
diastolic blood pressure 4-6 mmHg). The effect of this increase is to be of low
clinical relevance for healthy individuals in the general population under
normal environmental conditions.
- The patient will receive a radiation burden of the additional thoracal
[18F]FDG PET/CT that is expected to be in the range of 4.0 mSv (3.0 mSv
contributing to [18F]FDG and 1.0 mSv contributing to the low dose CT) for an
average sized adult. This is within category IIb of the 2016 NCS report: Human
exposure to ionizing radiation for clinical and research purposes: radiation
dose & risk estimates This is justified as the benefits of this study directly
aimed at improvement of diagnosis, which is a category IIb justification.
- The patient will have direct benefits of participation in this study. Due to
myocardial [18F]FDG uptake, their routine exam was not able to exclude
myocardial involvement. In systematic sarcoidosis it is reported that 2-7 % of
the patients have myocardial involvement In cardiac sarcoidosis only 5% of the
patients show clinical symptoms at the beginning of the disease. Therefore,
early recognition of silent cardiac disease is very important for patients to
start with medication to prevent serious adverse cardiac events. The only way
to detect cardiac inflammation in the earliest stage is [18F]FDG. Early
detection is also important in systematic vasculitides. Since, cardiac
involvement is also present in less than 10% of the patients and can cause
adverse cardiac events. In our study, the re-exam with additional caffeine
might provide sufficient [18F]FDG myocardial uptake reduction to exclude or
determine silent myocardial involvement in the patients. This will improve the
diagnosis for the patient. Furthermore, if the patient will be diagnosed with
silent myocardial involvement, this will change the treatment management and
possibly prevent adverse cardiac events in the future.