Characterization of bruises using ultrasonography for potential application in diagnosis of child abuse
Article Outline
- Abstract
- 1. Introduction
- 2. Materials and methods
- 3. Results
- 4. Discussion
- Acknowledgments
- References
- Copyright
Abstract
To protect children from abuse, it is important to identify victims at an early date, but diagnosis is often difficult. We used ultrasonography for objective examination of bruises arising from subcutaneous hemorrhages, and determined whether we could precisely measure the depth and thickness of a subcutaneous hemorrhage. We compared macroscopic findings, microscopic findings and ultrasonographic images of 10 bruises in forensic autopsy cases. In addition, we measured chronologic changes in subcutaneous hemorrhages using ultrasonography of 16 bruises in healthy volunteer children. Mild or moderate subcutaneous hemorrhages spreading along the fibrous partition in subcutaneous fatty tissue were observed by histological examination. There was a thickened fibrous partition or an isoechoic or hyperechoic area in the ultrasonographic images. A good correlation between the thickness of the subcutaneous hemorrhages by macroscopic examination and by ultrasonographic imaging was found in postmortem cases. We were also able to confirm objectively that the thickness of the subcutaneous hemorrhage of healthy children decreased with time. It is possible to measure the depth from the skin surface to the subcutaneous hemorrhage, and the thickness of the subcutaneous hemorrhage accurately using ultrasonography. Thus, the age of a bruise can be estimated more precisely using information on the subcutaneous hemorrhage from ultrasonography in addition to established evaluations by the naked eye and by spectrophotometry.
Keywords: Bruise, Child abuse, Forensic medicine, Subcutaneous hemorrhage, Ultrasonography
1. Introduction
The skin is the most common organ involved in accidental or non-accidental injury in children, and up to 90% of victims of physical abuse present with skin features [1]. In particular, bruises are found in 90% of physical abuse cases, and the coexistence of old and fresh bruises is strong evidence for a diagnosis of chronic abuse [2]. In the diagnosis of child physical abuse, the means by which the bruise was inflicted and the age of the bruise should be determined by macroscopic observation of external aspects (such as form, color and size) of a bruise.
We previously used spectrophotometry to estimate the age of a bruise by evaluating the color of a bruise, and found that the part of the body (depth from the skin surface to the subcutaneous hemorrhage) and the thickness of subcutaneous hemorrhage have a great influence on the color changes of a bruise [3], [4]. The color of a bruise depends not only on its age, but also on its site and depth, as well as the complexion of the skin [1]. However, it is difficult to measure the depth and thickness of a subcutaneous hemorrhage in the living body. Ultrasonography is suitable for measuring these factors, but ultrasonographic imaging of subcutaneous hemorrhages has not been established. This study investigated whether the depth and thickness of the subcutaneous hemorrhage of a bruise could be evaluated precisely using ultrasonography.
2. Materials and methods
We used an ultrasonograph (SonoSite180PLUS, SonoSite, Inc., USA), which is a small portable machine. A linear probe (L38/10-5, SonoSite, Inc., USA), which provided superior observation of superficial tissue, was connected to the ultrasonograph. Miyauchi et al. reported that a 10
MHz transducer was considered appropriate, although the detailed echograms were obtained mostly in the deep dermal and subcutaneous structures [5], and the probe we used had a 5–10MHz transducer.
When ultrasonographers observe subcutaneous tissue by ultrasonography, they need to be attentive to good practice. Fornage et al. warned in their report that variations in the pressure of the transducer on the skin may alter the apparent thickness and echogenicity of the skin [6]. Sonographers should be aware of this fact and use the minimum pressure necessary to obtain a satisfactory scan. It is also crucial to maintain the ultrasound beam (i.e., the transducer) perpendicular to the surface of the skin at all times to avoid artifacts due to scattering [6]. These are very important points, and the ultrasonographic examination in this study was performed by a skilled examiner to ensure good practice. The two methods we used are described below.
2.1. Comparison of macroscopic findings, microscopic findings and ultrasonographic images of subcutaneous hemorrhages in postmortem cases
In forensic autopsy, we sometimes incise a bruise at right angles to the skin and observe the subcutaneous hemorrhage directly for the purpose of confirming the extent of the subcutaneous hemorrhage in a bruise. Ten bruises (five men and two women; mean, 42.9±23.7years) were studied by ultrasonography before skin incision. After skin incision, the extent of subcutaneous hemorrhage was observed macroscopically and a histological study (hematoxylin and eosin stain) was performed. Then we compared measurements of the thickness of the subcutaneous hemorrhage from the macroscopic findings with those from the ultrasonographic images.
2.2. Chronologic changes in the subcutaneous hemorrhage of a bruise using ultrasonography in healthy volunteer children
We examined 16 bruises in 8 healthy volunteer children (six boys and two girls) who acquired them in typical daily accidents. The mean age of these children was 5.5±2.7 (range, 1–10)years. The depth from the skin surface to the subcutaneous hemorrhage and the thickness of subcutaneous hemorrhage were measured using the ultrasonograph. Data were recorded every day until healing to measure chronologic changes. All the bruises were allowed to heal naturally, without treatment such as cold-packs during the healing process.
We obtained agreement from the parents of volunteer children who had bruises, and permission to conduct this study was obtained from the Kumamoto University Ethics Committee.
3. Results
3.1. Comparison of macroscopic findings, microscopic findings and ultrasonographic images of subcutaneous hemorrhages in postmortem cases
The comparison of macroscopic findings, microscopic findings and ultrasonographic images of three representative postmortem cases, two females aged 24 and 29years and a 22-year-old male, are shown in Fig. 1 (Table 1, No. 1) (mild subcutaneous hemorrhages) and Fig. 2 (Table 1, No. 10) (mild subcutaneous hemorrhages) and Fig. 3 (Table 1, No. 3) (moderate subcutaneous hemorrhage). The complete data obtained for all cases in this study are summarized in Table 1, the subcutaneous hemorrhages were mild or moderate, as the hemorrhages were found to be scattered along the fibrous partition in the subcutaneous fatty tissue in the histological examination. Thickening of the fibrous partition (hyperechoic) or an isoechoic or hyperechoic area spread in fatty tissue were observed in the ultrasonographic images. In addition, the thickness of the subcutaneous hemorrhage in the macroscopic examination and in the ultrasonographic images showed significant correlation, with a Spearman’s rank correlation coefficient of 0.92497 (p<0.001).
Fig. 1.
Mild subcutaneous hemorrhage on the thigh of a 24-year-old female at postmortem. (a) Macroscopic findings (black arrow: subcutaneous hemorrhages); (b) microscopic findings (HE staining; black arrow: hemorrhages were found to be scattered along the fibrous partition); and (c) ultrasonographic image (white arrow: thickening of the fibrous partition (hyperechoic) with an isoechoic area).
Table 1. Summary of 10 bruises in forensic autopsy cases.
| No. | Age | Sex | Region | Size (cm) | Depth (cm) | Macroscopic thickness (cm) | Thickness by ultrasonography (cm) | Macroscopic findings of subcutaneous hemorrhage | Ultrasonographic findings |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 24 | F | Thigh | 1×1 | 0.2 | 0.3 | 0.26 | Mild | ∗2 |
| 2 | Lower leg | 0.5×0.4 | 0.1 | 0.3 | 0.22 | Mild | ∗2 | ||
| 3 | 22 | M | Thigh | 7×9 | 0.5 | 1.5 | 1.52 | Moderate | ∗4 |
| 4 | 22 | M | Forearm | 2.4×2.2 | 0.3 | 0.3 | 0.38 | Mild | ∗2 |
| 5 | 65 | M | Forearm | 3.3×2.4 | 0.2 | 0.7 | 0.75 | Moderate | ∗3 |
| 6 | 62 | M | Shoulder | 5.5×2.8 | 0.4 | 0.4 | 0.61 | Moderate | ∗4 |
| 7 | Groin | 6.2×2.8 | 0.5 | 0.6 | 0.54 | Moderate | ∗3 | ||
| 8 | 76 | M | Knee | 5×3 | 0.5 | 0.8 | 1 | Moderate | ∗4 |
| 9 | Thigh | 7×1.7 | 0.5 | 0.5 | 0.5 | Moderate | ∗3 | ||
| 10 | 29 | F | Lower leg | 5×2 | 0.2 | 0.25 | 0.36 | Mild | ∗1 |
Fig. 2.
Mild subcutaneous hemorrhage on the lower leg of a 29-year-old female at postmortem. (a) Macroscopic findings (black arrow: subcutaneous hemorrhages); (b) microscopic findings (hematoxylin & eosin (HE) staining; black arrow: hemorrhages were found to be scattered along the fibrous partition); and (c) ultrasonographic image (white arrow: thickening of the fibrous partition (hyperechoic).
Fig. 3.
Moderate subcutaneous hemorrhage on the thigh of a 22-year-old male at postmortem. (a) Macroscopic findings (white arrow: subcutaneous hemorrhages); (b) microscopic findings (HE staining; black arrow: hemorrhages were found to be scattered along the fibrous partition); and (c) ultrasonographic image (white arrow: an isoechoic or hyperechoic area scattered around the fibrous partition).
3.2. Chronologic changes in the subcutaneous hemorrhage of a bruise using ultrasonography in healthy volunteer children
Descriptions of the bruises in the children are presented in Table 2. A thin subcutaneous hemorrhage was observed as a thickening of the fibrous partition (hyperechoic), sometimes with an isoechoic area. Thicker bruises were observed as an isoechoic or hyperechoic area scattered around the fibrous partition.
Table 2. Summary of 16 bruises in healthy volunteer children.
| No. | Age (y) | Sex | Region | Cause of bruise | Time after bruise (hrs) | Size (cm) | Depth (cm) | Thickness by ultrasonography (cm) | Ultrasonographic findings |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 5 | M | Lower leg | Fall | 29 | 2.5×1.5 | 0.2 | 0.22 | ∗2 |
| 2 | Lower leg | Fall | 9 | 2.2×1.5 | 0.17 | 0.43 | ∗3 | ||
| 3 | Thigh | Fall | 27 | 1.5×1.5 | 0.24 | 0.14 | ∗1 | ||
| 4 | 6 | M | Cheek | Hit by blunt object | 67 | 2.7×5.4 | 0.25 | 0.38 | ∗2 |
| 5 | Cheek | Hit by blunt object | 67 | 3.7×1.7 | 0.43 | 0.28 | ∗2 | ||
| 6 | Cheek | Hit by blunt object | 67 | 1.8×1.3 | 0.33 | 0.39 | ∗3 | ||
| 7 | 5 | M | Chest | Fall | 3 | 1×0.9 | 0.19 | 0.46 | ∗3 |
| 8 | Lower leg | Fall | 18 | 1.7×1.7 | 0.25 | 0.22 | ∗2 | ||
| 9 | Elbow | Fall | 20 | 1.8×1.3 | 0.32 | 0.12 | ∗1 | ||
| 10 | Knee | Fall | 39 | 1.4×1.7 | 0.19 | 0.16 | ∗1 | ||
| 11 | 10 | F | Anterior arm | Unascertained | 19 | 1.4×1.6 | 0.25 | 0.48 | ∗3 |
| 12 | Knee | Unascertained | 19 | 1.5×1.6 | 0.22 | 0.83 | ∗4 | ||
| 13 | 7 | F | Thigh | Unascertained | 87 | 10×10 | 0.25 | 1.3 | ∗4 |
| 14 | 1 | M | Cheek | Hit by blunt object | 87 | 0.8×1.3 | 0.16 | 0.36 | ∗2 |
| 15 | 3 | M | Thigh | Hit by blunt object | 14.5 | 0.9×1.0 | 0.33 | 0.25 | ∗2 |
| 16 | 7 | M | Buttock | Fall | 54 | 3×2.8 | 0.24 | 0.68 | ∗3 |
Fig. 4 shows a comparison of ultrasound imaging of a bruise (left buttock) and control (right buttock) in a healthy child (Table 2, No. 16). A Mongolian spot was found in a part of the surface of the right buttock (Fig. 4a). An isoechoic area of subcutaneous hemorrhage was clear in the bruise (Fig. 4b) and was different from the slight linear hyperechoic pattern of the fibrous partition in the control (Fig. 4c). An isoechoic area of subcutaneous hemorrhage was not observed in the Mongolian spot.
Fig. 4.
(a) Bruise on the left buttock of a healthy 7-year-old boy resulting from a fall down stairs. Comparison of ultrasound imaging of the bruise and control skin (including the Mongolian spot): (b) an isoechoic area (surrounded by white arrows) of the subcutaneous hemorrhage in the left buttock; and (c) control (including the Mongolian spot): a slight linear hyperechoic pattern of the fibrous partition (white dotted line arrows) in the right buttock.
The depth from the skin surface to the subcutaneous hemorrhage did not generally change with time, although there were a few exceptions (Fig. 5). In contrast, we were able to confirm that the thickness of a subcutaneous hemorrhage decreased with time after suffering a bruise, as shown in Fig. 6.
Fig. 5.
Time-dependent changes using relative thickness changes (%) of the depth from the skin surface to a subcutaneous hemorrhage in an ultrasonograph after suffering a bruise.
Fig. 6.
Time-dependent changes using relative thickness changes (%) of a subcutaneous hemorrhage in an ultrasonograph after a bruise was incurred.
4. Discussion
The diagnosis of most skin diseases has, in the past, relied mainly on physical findings, but ultrasonographic imaging has been employed recently in dermatology [7], [8]. This non-invasive and accurate method is used for diagnosing skin tumors, psoriasis, scleroderma, inflammatory conditions, and cysts [7], [8]. In the last decade, the ultrasonographic technique has been applied to the measurement of soft tissue thickness in the forensic field [9], [10], [11], [12]. However, ultrasonographic characterization of a subcutaneous hemorrhage has not generally been performed conventionally in the field of clinical medicine because it is not a trauma requiring aggressive treatment.
Subcutaneous tissues consist primarily of fat with a variable amount of connective tissue in the form of scattered fibrous tissue mainly running parallel to the skin. The subcutaneous fat is hypoechoic and contains linear echoes representing strands of connective tissue, which is the fibrous partition in subcutaneous fatty tissue [6]. The sonographic appearance of hematomas confined to the subcutaneous fat has not been extensively evaluated. It is known from conventional studies that fresh hematomas following a contusion appear as an ill-defined hyperechoic area [7]. In the present study, the mild subcutaneous hemorrhages in postmortem cases were represented by a thickening of the fibrous partition (hyperechoic) sometimes with an isoechoic area, while the moderate subcutaneous hemorrhages in postmortem cases were represented by an isoechoic area and/or hyperechoic area scattered around the fibrous partition in ultrasonographic images. Additionally, the ultrasonographic images of the subcutaneous hemorrhages in healthy children showed the same features as the postmortem ultrasonographic images of subcutaneous hemorrhages. It was thought that echoes were scattered by diffuse hemorrhaging along the fibrous partition. The primary focus of the subcutaneous hemorrhage in a bruise is based on the rhexis of capillary vessels along the fibrous partition in subcutaneous fatty tissue by external force. Because mild hemorrhaging spreads only around the fibrous partition (hyperechoic), it may appear as a thickening of the fibrous partition in the ultrasonograph. A moderate hemorrhage spreads around the fibrous partition and the echo enlarges, appearing as an isoechoic or hyperechoic area scattered around the fibrous partition.
In the present study, there was a good correlation between the thickness of the subcutaneous hemorrhage measured postmortem in the macroscopic findings with that of the ultrasonographic images. Although the degree of accuracy of ultrasonographic measurement is high, a measurement error may appear because it is difficult to distinguish the fibrous partition and the subcutaneous hemorrhage of the isoechoic or hyperechoic area.
This study has shown that we can determine the depth from the skin surface to the subcutaneous hemorrhage and the thickness of the subcutaneous hemorrhage in the bruises of healthy children (living body) using ultrasonography. Skin thickness varies greatly, depending on the site examined [6], and the thickness of subcutaneous fatty tissue shows even greater variation. These thicknesses are associated with the depth from the skin surface to the subcutaneous hemorrhage, and have an effect on the color of the bruise. In addition, it is very important that we have been able to visualize that the thickness of a subcutaneous hemorrhage decreases with time after a bruise is incurred. The thickness of a subcutaneous hemorrhage also has an effect on the color of the bruise. Macroscopic and spectrophotometric examinations of bruises have limitations in evaluating subcutaneous hemorrhages because they depend solely on the external changes in the color of the bruise. Actually, in this present study, the ultrasonographic data were also helpful to distinguish skin discoloration such as a Mongolian spot from a subcutaneous hemorrhage. Determination of the depth from the skin surface to the subcutaneous hemorrhage and the thickness of a subcutaneous hemorrhage precisely may provide a clue that adds to the accuracy of the spectrophotometric evaluation of a bruise.
We believe that this is the first report of ultrasonographic imaging of subcutaneous hemorrhages. The results of this study indicate that ultrasonography can provide an accurate evaluation of a bruise, and has the potential to allow a more accurate estimate of the age of a bruise along with examination by the naked eye and by spectrophotometry.
Acknowledgments
This research is supported in part by the Uehara Memorial Foundation, and a Grant-in-Aid for Young Scientists (B) from the Ministry of Education, Culture, Sports, Science and Technology.
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PII: S1344-6223(11)00115-5
doi:10.1016/j.legalmed.2011.09.007
© 2011 Elsevier Ireland Ltd. All rights reserved.
