Introduction

Estimating the time since death is crucial in forensic casework and various methods are used to determine it, such as body cooling, rigor mortis, postmortem lividity, and supravital reactions [1].

Although less common, a forensic scientist must also be prepared to estimate the time since death from gastric contents when such evidence is presented [2]. Previously, estimating the time since death by gastric content analysis has helped to refute witness statements and ultimately solve the case [3, 4].

While qualitative stomach content analyses are performed to identify the last meal of the deceased and its nature (e.g. breakfast, lunch or dinner) [5, 6], or possible intoxications [7], quantitative stomach content analysis aims to estimate the timeframe between the last meal and death [6].

Previous studies have shown that gastric emptying occurs continuously after meal intake and stops at death, as there is no relevant peristalsis to further transport gastric contents into the duodenum [8, 9]. If the last meal consumed by the deceased and the residual stomach content are known, the time interval between meal intake and death can indirectly be estimated by using reference gastric emptying data [10, 11].

Horowitz et al. recommended using only the gastric emptying times of the solid components of a meal since fluids empty from the stomach at different and generally faster rates [11].

However, gastric emptying times vary among individuals and are influenced by various factors such as meal-related factors (e.g. weight, volume, composition, total calorie count) [2], as well as personal factors (e.g. diabetes, pain, stress, increased cerebral pressure) [11].

Current data on gastric emptying times are mostly derived from gastroenterological studies that used standardized test meals (liquids, semi-solids, small portions) to examine isolated effects on gastric emptying [12]. These experimental conditions do not directly reflect everyday meals in which various influencing factors interact.

Tröger et al. provided gastric emptying curves including confidence intervals for mixed meals (containing meat, carbohydrates and plant ingredients) and carbohydrate meals based on autopsy data [10]. Although the authors differentiated between two meal types, there is no description of the initial meal sizes or further details on the included meals. Additionally, the authors compared various gastric emptying studies and drew the following conclusions: a small meal is completely emptied from the stomach after 1–3 h, an average meal after 3–5 h and a large, voluminous meal after 5–8 h. However, the study does not define portion size, nor is it clear if and how meal composition was considered.

Therefore, this exploratory study investigates the effect of different macronutrient compositions on the gastric emptying times of conventionally sized solid meals using magnetic resonance imaging (MRI). It aims to provide reference data that may support stomach content death time estimations in forensic practice.