Determining the effect of water temperature on the T1 and T2 relaxation times of the lung tissue at 9.4 T MRI: A drowning mouse model. (March 2021)

• Record Type: Journal Article
• Authors: Kodama, Saki; Hata, Junichi; Kanawaku, Yoshimasa; Nakagawa, Hiroshi; Oshiro, Hinako; Saiki, Erisha; Okano J., Hirotaka; Iwadate, Kimiharu
• Is Part Of: Legal medicine. Volume 49(2021)
• Publication Date: 2021-03
• Subjects: NMR nuclear magnetic resonance -- MRI magnetic resonance imaging -- TE echo time -- ROI region of interest' Control, non–drowning sudden death model made by cervical dislocation -- Cold cold water temperature drowning model -- Normal normal water temperature drowning model -- Warm lukewarm water temperature drowning model -- Hot hot water temperature drowning model; Lung tissue -- Pulmonary -- T1 relaxation time -- T2 relaxation time -- Postmortem MRI -- Drowning -- Forensic; Medical jurisprudence -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Medical jurisprudence; Periodicals; 614.1
• DOI: 10.1016/j.legalmed.2020.101836
• Languages: English
• ISSNs: 1344-6223

Abstract

Highlights: T1 relaxation time of the drowning lung was linearly dependent on water temperature. In the lung areas of the same individuals, T2 value decreased after drowning. Basic data of drowning lung in postmortem MRI were provided. Abstract: Japanese individuals have a unique culture of soaking in a bathtub, and forensic pathologists have experienced fatal cases due to drowning. However, T1 and T2 relaxation times of a drowning lung are poorly documented. In the present study, we investigated the relationship between drowning water temperature and T1 and T2 relaxation times of drowning lung tissues at 9.4 T MRI (Bruker, BioSpec94/20USR). The mice used as animal drowning models were directly submerged in freshwater. Water temperature was set to 8 °C–10 °C (cold), 20 °C–22 °C (normal), 30 °C, and 45 °C. The regions of interest (ROIs) on the axial section of the third slice were set at the central and peripheral areas of each—the left and the right—lung. T1 relaxation times measured immediately after death differed by the presence or absence of soaking water, except in case of cold water temperature. In the drowning groups, T1 relaxation time showed a linear dependency on water temperature. By contrast, T2 relaxation time was almost constant regardless of the presence of drowning under the same temperature condition; when compared in the lung areas of the same individuals, the times were uniformly reduced in drowning models. To minimize the effects of hypostasis and decomposition, we performed measurements immediately after death and were able to determine the noticeable difference in drowning water temperature. These results may be useful for qualitative assessments of a drowning lung and may serve as a basis when imaging the human body during forensic autopsy cases.