AIMS AND OBJECTIVES

Aim: To evaluate the effect of dietary modification with low carbohydrate, high fat (LCHF) diet on intestinal ¹⁸F-FDG uptake.


 Objectives: The present study intends to:

1. To compare SUV max value of physiological FDG uptake in routine diet and LCHF diet.

2.  To evaluate the effect of diet on intestinal ¹⁸F- FDG uptake by measuring SUV max of different parts of intestine.

Site: Department of Nuclear Medicine, Army Hospital Research and Referral, New Delhi.

Block Randomization

The research will employ a Block Randomization strategy using the Sealed Envelope System. Ten sealed opaque envelopes, labelled A and B (5 envelopes each) will be prepared. Among these, 5 envelopes will be assigned to the Native group (Routine Diet), and 5 to the LCHFD group. Upon a patient’s consent to participate, an envelope will be randomly chosen and opened, determining the group allocation for the patient. This randomization approach will involve 20 blocks, each comprising 10 patients. In each block, 5 patients will be designated to the Native group, and the remaining 5 to the LCHFD group.

Inclusion criteria: 

Patients undergoing PET/CT scan. 

Exclusion criteria: 

l   Unwilling patients

l   Known diabetics.

l   Drugs affecting gut motility and uptake.

l   Serum glucose level of more than 200 mg/dl

l   Failure to fast

l   Failure to comply with dietary modification.  

l   Known bowel disease.

l   Patients with sepsis

l   Patients with deranged hematology and biochemistry parameters.

l   Pregnant and lactating women.

l   Patients unable to undergo PET/CT

l   Claustrophobic patients.

Data collection:

·         All patients will be subjected to a thorough clinical evaluation as per standard guideline.

·         Patient’s details including history, clinical examination findings, relevant investigation & treatment history will be recorded as per proforma attached.

Methods:

l   Patients will be randomly assigned into 2 groups, with one group taking a routine diet (RD) and the other an LCHFD for 48 h before the ¹⁸F-FDG PET/CT scan. All patients will receive the required details about their diet and will be instructed to fast for at least 6 h before the study.

l   For 48 h before the study any carbohydrate-containing beverages or meals will be avoided.

l   Computer generated randomization (block randomization) will be done.

l   Allocation concealment will be done using opaque envelope.

l   PET/CT will be performed approximately 60 min after intravenous administration of 392 + 63 MBq (10.6 + 1.7 mCi) of ¹⁸F-FDG according to body weight (5.2 MBq/kg [0.14 mCi/kg]) using a whole-body four-ring dedicated LYSO PET/ CT scanner - GE Discovery MI DR. CT images will be obtained using 120 KV and auto mAs for CT based attenuation correction and localization of the lesions. Images will be reconstructed using standard iterative algorithm (OSEM) and reformatted into Transaxial, Coronal and Sagittal views. A 3D image and fusion images of PET & CT will be obtained.

·         ¹⁸F-FDG PET/CT scan findings will be interpreted independently by 2 nuclear medicine physicians. Patients with high tumour volume load or inadequate myocardial suppression will be excluded from the study.

l   The uptake in the small intestine and different parts of the large bowel (Duodenum, Jejunum, Ileum, ICJ, Ascending colon, Descending colon, Transverse colon, Hepatic flexure, Splenic flexure, Sigmoid Colon and Rectum) will be assessed quantitatively using SUVmax and qualitatively using visual assessment score.

l   The intensity of uptake in the different parts of intestine will be classified qualitatively based on visual assessment. The visual assessment score is based on the Likert scale used for Myocardial FDG uptake.