View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by RERO DOC Digital Library Eur Radiol (2008) 18: 283–290 DOI 10.1007/s00330-007-0745-4 FORENSIC MEDICINE Andreas Christe Drowning—post-mortem imaging findings Emin Aghayev Christian Jackowski by computed tomography Michael J. Thali Peter Vock Abstract The aim of this study was to the lung resulted in hypodensity of the Received: 20 February 2007 Revised: 29 June 2007 identify the classic autopsy signs of blood representing haemodilution and Accepted: 20 July 2007 drowning in post-mortem multislice possible heart failure. Swallowed Published online: 29 August 2007 computed tomography (MSCT). water distended the stomach and du- # Springer-Verlag 2007 Therefore, the post-mortem pre- odenum; and inflow of water filled the autopsy MSCT- findings of ten paranasal sinuses (100%). All the drowning cases were correlated with typical findings of drowning, except . A. Christe (*) P. Vock autopsy and statistically compared Paltau’s spots, were detected using Institute of Diagnostic Radiology, with the post-mortem MSCT of 20 post-mortem MSCT, and a good cor- University Hospital, Freiburgstrasse, non-drowning cases. Fluid in the air- relation of MSCT and autopsy was 3010 Bern, Switzerland ways was present in all drowning found. The advantage of MSCT was e-mail: [email protected] cases. Central aspiration in either the the direct detection of bronchospasm, Tel.: +41-31-6322111 trachea or the main bronchi was haemodilution and water in the para- Fax: +41-31-6323224 usually observed. Consecutive bron- nasal sinus, which is rather compli- A. Christe . E. Aghayev . chospasm caused emphysema aquo- cated or impossible at the classical C. Jackowski . M. J. Thali sum. Sixty percent of drowning cases autopsy. Center Forensic Imaging and Virtopsy, showed a mosaic pattern of the lung Institute of Forensic Medicine, parenchyma due to regions of hypo- Keywords Virtopsy . Drowning . University of Bern, . Buehlstrasse 20, and hyperperfused lung areas of aspi- Post-mortem Multislice computed 3012 Bern, Switzerland ration. The resorption of fresh water in tomography Introduction related to young adults who are under the influence of alcohol and other drugs whilst being near water [5, 6]. A generally used definition of drowning is given by Roll The pathophysiological aspects of drowning are complex. [1]: “Death by drowning is the result of a hampering of Ten percent of drownings happen without aspiration of respiration by obstruction of mouth and nose by a fluid fluid in the lung [7, 8]; this is the so-called “dry drowning” medium (usually water)”. Generally, bodies retrieved from due to a laryngospasm because of hypoxia and stimulus of water may have: (1) died of natural disease before falling water in the upper respiratory ways (larynx) [9, 10]. The into the water, (2) died of natural disease while already in remaining 90% of drownings are so-called “wet drown- the water, (3) died from injury before being thrown into the ing”: the volume and composition of aspirated fluid water, (4) died of injury while in the water, (5) died of determine the physiological basis of hypoxemia [11–13]. effects of immersion other than drowning, (6) died of Aspiration of fresh water dilutes the pulmonary surfactant drowning (true drowning). According to the World Health and makes alveoli unstable [14], which leads to the Organisation, the annual worldwide incidence of death by collapse and atelectasis of some of the alveoli. Intrapul- drowning is about 400,000 [2]. Death from drowning is monary shunt occurs with considerable pulmonary venous more common in young children [3]. In adults, suicide is a admixture [15]. The appearance of hypotonic fresh water in frequent cause of drowning, which is often associated with the alveoli is not usually a problem, because it is rapidly past psychiatric history [4]. Drowning has especially been absorbed into the pulmonary and systemic circulation with 284 dilution of the blood and hypervolemia [16]. The passive Autopsy was performed by board-certified forensic postmortal inflow of water is low [17–19]. On the other pathologists, which were blinded to the results of the CT hand, aspiration of sea water leads to perfused and fluid- studies. Classical autopsy procedure was used. filled alveoli. The hypertonic sea water pulls additional Potential forensic key findings of drowning at autopsy fluid from the plasma, leading to pulmonary edema and were looked for at MSCT of the ten drowning and 20 non- hypovolemia and adding to the ventilation-perfusion drowning cases. abnormality [20, 21]. The distribution, amount and content of aspiration in the Intrabronchial water can cause substantial broncho- airways were assessed. Since the detection of aspiration in spasm, which results in pulmonary emphysema, also the airways is rather easy in MSCT, its density could be known as emphysema aquosum [22]. The fluid aspiration measured in Hounsfield Units (HU) to characterise the followed by bronchospasm is more multifocally scattered content. Fluid in the airways was called “watery fluid” throughout the lung than diffuse, which results in a mosaic when the density was below 30 HU and “dense fluid” when pattern of dry, hypoperfused and wet, hyperperfused lung its density was equal or higher than 30 HU. Watery fluid areas [23]. was further subdivided into foamy water, when bubbles of Pulmonary arterial hypertension and hypervolemia lead very low densities of 1 to –1,000 HU were present. The also to heart failure, accentuated on the right side. amount of aspiration was classified into three groups. It During the act of conscious drowning a lot of water is was low when it filled up to one-third of the tracheal/ swallowed [24], which leads to a distention of the stomach bronchial volume, high when it filled more than two-thirds, and duodenum. In addition an inflow of water into the and was medium in-between the two. paranasal sinuses may frequently occur [25]. Any multifocal ill-defined air space densities in depen- For “near drowning patients”, findings are already dent lung areas with normal calibres of the vessels were known; sand aspiration occurs [26] and pulmonary changes considered as signs of aspiration into the lung. can be found in computed tomography (CT): predominant For the assessment of emphysema aquosum, the stance centrally located ground-glass opacities with or without of the dome of the right diaphragm on the basis of the associated reticular opacities and centrilobular nodules [27]. anterior ribs was determined. The minimal distance The intention of this paper is to present the CT findings between the left and right lung was also measured (width of drowning cases and their correlation with autopsy of the retrosternal mediastinum). findings. Additionally, the bronchial diameters were compared with the diameters of the accompanying pulmonary artery, based on the hypothesis that aspiration leads, on one hand, Materials and methods to bronchospasm and, on the other hand, to dilatation of the pulmonary artery (resorption of the water). A segmental During the period from 2000 to 2005 ten cases of true broncho-vascular bundle of the middle lobe or the lingula drowning were examined at the Institute of Forensic was examined and the bronchial-arterial coefficient (i.e. the Medicine in Berne within the Virtopsy project [28]; two diameter of the bronchus divided by the diameter of were female, eight male; the median age at death was 52 accompanying pulmonary artery) was calculated. The years, ranging from 13 to 81. MSCT and autopsy were middle lobe or lingula was chosen for measuring, because performed at a median of 43 h and 58 h after death, the non-dependent lung areas showed less pulmonary respectively. According to the Virtopsy protocol, the edema and/or aspiration that troubled the exact analysis. deceased received post-mortem CT and magnetic reso- To evaluate laryngospasm, the posterior distance be- nance imaging (MRI), followed by the classical forensic tween the vocal cords was measured. autopsy. The control group consisted of 20 non-drowning To assess heart failure, the cardio-thoracic ratio (CTR = cases, where the atrium mortis was the brain. This group maximum transverse cardiac diameter/transverse thoracic consisted of six females and 14 males; the median age at diameter) was measured on MSCT images and the cross death was 43, ranging from 19 to 73. MSCT and autopsy sectional area of the inferior vena cava (IVC) was measured were performed at a median of 35 h and 49 h after death, at the level below the right atrium and above the liver. The respectively. individual size of the heart chambers was acquired semi- Multislice CT (MSCT) was performed on a GE Light- quantitatively using a scale from 0 to 3 (0 indicating normal speed QX/I unit (General Electric, Milwaukee,Wis., USA). volume). Axial slices were accuired with a collimation of 4 mm× As signs of pulmonary edema, dependent lung areas 1.25 mm; 5-mm and 1.25-mm sections, as well as sagittal with diffuse or multifocal air space consolidation and with and coronal reformations, were calculated. The MSCT scan interstitial opacities surrounding enlarged pulmonary took between 10 and 15 min. Two board-certified vessels were looked for, as well as accompanying pleural radiologists, blinded to the autopsy findings, retrospec- effusion. tively evaluated the CT scans in common (consensus Since it is known that people with anemia have a viewing). lower density of blood [29], because of the low level of 285 haemoglobin, which is a major contributor to the density The findings of the drowning and control groups were of blood, haemodilution of blood in each case was statistically compared by the Wilcoxon signed rank test. A assessed by measurement of the blood density in the right P≤0.05 is significant and labelled with the number 1, P< and left atrium.