The distal femoral epiphysis in forensic age diagnostics: studies on the evaluation of the ossification process by means of T1- and PD/T2-weighted magnetic resonance imaging.

The age of majority, which corresponds to the age of 18 years in most European countries, plays a crucial role for a large number of legal decisions. Accordingly, an increasing number of requests by authorities to forensic age estimation experts comprise the question of whether the age of 18 years has been reached by an individual. In recent years, novel study data suggested that magnetic resonance imaging (MRI) of the knee might likewise allow for the determination of majority beyond reasonable doubt. However, the data basis, especially concerning the distal femoral epiphysis (DFE), is still poor. For this reason, 392 routine MRI cases of the knee (204 males and 188 females of a Western Caucasian population, aged between 12 and 25 years) were retrospectively analyzed. T1-weighted and water-selective fat-saturated PD/T2-weighted sequences, generated at 1.5 and 3.0 T clinical MR scanners, were available. Ossification stages of the DFE were determined by means of the classification system by Vieth et al. (Eur Radiol 2018; 28:3255-3262). Both the intra-observer agreement and inter-observer agreement were found to be "very good" (κ = 0.899 and κ = 0.830). The present study confirmed that MRI of the DFE is suitable to determine majority in both sexes when stage 6 is present as the study revealed minimum ages above the age of 18 years for this stage (20.40 years in males and 20.60 years in females). Accordingly, the data represent a strong support for the so far existing database. Hence, the investigation of the knee using routine MRI appears to become a realistic alternative for forensic age estimation practice in the near future.

Characterization of subdural collections in initial neuroimaging of abusive head trauma: Implications for forensic age diagnostics and clinical decision-making.

PURPOSE: Subdural collections (SDCs) represent a key finding in abusive head trauma (AHT), a serious form of child physical abuse. Common SDC entities in this context are subdural hematoma (SDH), subdural hygroma (SDHy), subdural hematohygroma (SDHHy), and chronic subdural hematoma (cSDH). The present study examines the prevalence of the different SDC entities and investigates the influence of the SDC diagnosis on the forensic age estimation of the injury. METHODS: In this retrospective multi-center study from three German university hospitals of a 10-year period, the initial neuroimaging material (CT or MRI) of 56 children (36 males, 20 females; age median 3.9 months) with medico-legally well-documented AHT was analyzed. SDCs were characterized by determining presence, location, extension, and visual appearance, by assigning to one of the five entities, and by categorizing with three different classification systems, one of which represents a novel system based on focality and Mixed Appearance Pattern and especially developed for children with AHT. The data were correlated with demographic and clinical data. By means of court files, AHT cases were also sub-divided into confession (n = 14) and non-confession cases (n = 42) and then compared. RESULTS: Most cases showed a multifocal presence of SDCs (96.4%) and the presence of a Mixed Appearance Pattern (82.1%). The most common SDC entity was the heterogeneous variant of the SDHHy (66.1%). The cSDH occurred infrequently only (3.6%). Our novel classification system illustrates that unifocal SDCs rarely occur in AHT, and that more complex SDC patterns are common. In nearly all cases (94.6%), additional signs of recently caused brain injury were present beside the SDCs. Comparison between confession and non-confession groups did not reveal any significant differences, indicating that the diagnostic criteria of AHT are robust. CONCLUSIONS: Although precise dating of SDCs based on initial neuroimaging alone remains unrealistic, the exact diagnosis of the SDC entity provide an important basis for differentiation between acute trauma and chronic post-traumatic state. Therefore, especially the confirmation or exclusion of subdural neomembranes, that define the cSDH, should be considered indispensable.

The role of 3DCT for the evaluation of chop injuries in clinical forensic medicine.

As hatchet blows to the human head frequently cause fatal injuries, the forensic examination of survivors with cranial chop injuries is a rare phenomenon in forensic casework. Besides evaluation of clinical records, photographs, and medico-legal physical examination, the analysis and 3-dimensional reconstruction of pre-treatment computed tomography data (3DCT) must be considered an important and indispensable tool for the assessment of those cases because the characteristics of chopping trauma often appear masked or changed by clinical treatment. In the present article, the role of 3DCT for the evaluation of chop wounds in clinical forensic medicine is demonstrated by an illustrative case report of a young man who was attacked with a hatchet. 3DCT provides additional possibilities for supplementing missing information, such as number and direction of blows as well as weapon identification. Furthermore, 3DCT facilitates demonstration in court and understanding of medical lay people. We conclude that 3DCT is of particular value for the evaluation of survivors of life-threatening head and face injury. An increasing significance of this technique may be expected.

Non-enhanced magnetic resonance imaging of the small bowel at 7 Tesla in comparison to 1.5 Tesla: First steps towards clinical application.

OBJECTIVE: To perform non-enhanced (NE) magnetic resonance imaging (MRI) of the small bowel at 7 Tesla (7T) and to compare it with 1.5 Tesla (1.5T). MATERIAL AND METHODS: Twelve healthy subjects were prospectively examined using a 1.5T and 7T MRI system. Coronal and axial true fast imaging with steady-state precession (TrueFISP) imaging and a coronal T2-weighted (T2w) half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence were acquired. Image analysis was performed by 1) visual evaluation of tissue contrast and detail detectability, 2) measurement and calculation of contrast ratios and 3) assessment of artifacts. RESULTS: NE MRI of the small bowel at 7T was technically feasible. In the vast majority of the cases, tissue contrast and image details were equivalent at both field strengths. At 7T, two cases revealed better detail detectability in the TrueFISP, and better contrast in the HASTE. Susceptibility artifacts and B1 inhomogeneities were significantly increased at 7T. CONCLUSION: This study provides first insights into NE ultra-high field MRI of the small bowel and may be considered an important step towards high quality T2w abdominal imaging at 7T MRI.

T1-Weighted Contrast-Enhanced Magnetic Resonance Imaging of the Small Bowel: Comparison Between 1.5 and 7 T.

OBJECTIVES: T1-weighted (T1w) contrast-enhanced magnetic resonance imaging (MRI) of the small bowel at 1.5 T magnetic field strength has become a standard technique in investigating diseases of the small bowel. High-field MRI potentially offers improved soft tissue contrast and spatial resolution, providing increased image detail. The purpose of this study was to evaluate the feasibility of contrast-enhanced small bowel MRI at 7 T and to compare results with 1.5 T. MATERIALS AND METHODS: Twelve healthy volunteers underwent small bowel MRI on a 1.5 T and 7 T MRI system. A coronal fat-saturated T1w spoiled gradient-echo sequence (3-dimensional [3D] FLASH) was applied precontrast and at 20 seconds, 75 seconds, and 120 seconds after intravenous contrast administration. Furthermore, late-phase coronal and axial fat-saturated T1w 2-dimensional (2D) FLASH data sets were acquired. Visual evaluation of tissue contrast and image detail of the small bowel wall and mesentery as well as contrast ratios were compared between 1.5 T and 7 T in an intraindividual comparison. In addition, subjective ratings of image impairment by artifacts were assessed at both field strengths. RESULTS: Magnetic resonance imaging of the small bowel at 7 T revealed equal tissue contrast and image detail compared with 1.5 T. Higher contrast and improved image detail of mesentery structures at 7 T were found in nonenhanced 3D FLASH. Quantitatively measured contrast between the bowel wall and bowel lumen showed significantly lower contrast at 7 T in nonenhanced 3D FLASH and in late-phase 2D FLASH. Image quality was more impaired at 7 T compared with 1.5 T, mainly due to increased susceptibility artifacts and B1 inhomogeneities. CONCLUSIONS: T1-weighted contrast-enhanced MRI of the small bowel at 7 T represents a promising MR technique for establishing ultra-high magnetic field strengths in clinical applications. Despite increased artifacts at 7 T, depiction of the small bowel was achieved with comparable quality to the current state-of-the-art field strength of 1.5 T. Assessment of potential diagnostic benefits should be the focus of future high-field MRI studies.

Imaging of bridging vein thrombosis in infants with abusive head trauma: the "Tadpole Sign".

OBJECTIVES: Abusive head trauma (AHT) in infants is usually diagnosed using a multi-disciplinary approach by investigating the circumstances and identifying morphological indicators, for example, subdural hematomas (SDHs), subdural hygromas (SDHys), retinal haemorrhages and encephalopathy. The present morphological study investigates the incidence, radiological characteristics and non-radiological co-factors of bridging vein thrombosis (BVT) in infants with AHT. METHODS: From 2002 to 2013, computed tomography (CT) and magnetic resonance imaging (MRI) material of 628 infants aged 0-2 years were analysed retrospectively. If available, medicolegal expert opinions were additionally considered. Cases with SDHs and/or SDHys were identified and systematically evaluated as to the presence and characteristics of BVT. RESULTS: SDHs and/or SDHys were present in 29 of the 81 cases exhibiting morphological abnormalities in the initial CT. Among these, 11 cases (40%) had BVT (mean age = 5.0 months). BVT could be best depicted in the T1-weighted spin echo and T2*/susceptibility-weighted MRI. In one case, BVT could be depicted indirectly using time-of-flight MR venography. The predominant (73%) BVT shape was found to be tadpole-like ("Tadpole Sign"). CONCLUSIONS: In the absence of appropriate accidental trauma, BVT appears to be a strong indicator of AHT. Therefore, the BVT/Tadpole Sign represents compelling cause to search for other signs of AHT. KEY POINTS: • BVT is an excellent indicator of AHT in SDH/SDHy cases. • Accidental trauma must be ruled out before diagnosing AHT. • The Tadpole Sign appears to be the most characteristic shape of BVT. • BVT can be depicted using CT, MRI and MR venography. • The Tadpole Sign suggests searching for other signs of AHT.

Magnetic resonance colonography including diffusion-weighted imaging in children and adolescents with inflammatory bowel disease: do we really need intravenous contrast?

OBJECTIVES: Magnetic resonance colonography (MRC) is a well-accepted, noninvasive imaging modality for the depiction of inflammatory bowel disease. Diffusion-weighted imaging (DWI) is very helpful to display inflammatory lesions. The aim of this retrospective study was to assess whether intravenous contrast is needed to depict inflammatory lesions in bowel magnetic resonance imaging if DWI is available. MATERIALS AND METHODS: Thirty-seven patients (23 females, 14 males; mean age, 14.6 years) underwent MRC on a 1.5-T scanner (MAGNETOM Avanto; Siemens). Contrast-enhanced T1-weighted (ce-T1-w) sequences and DWI sequences in axial and coronal planes (b = 50, 500, 1000) were acquired. Two reviewers evaluated (1) DWI, (2) ce-T1-w MRC, as well as (3) DWI and ce-T1-w MRC concerning lesion conspicuity. The preferred b value was assessed. Colonoscopy was performed within 1 week, including biopsies serving as the reference standard. Sensitivities and specificities were calculated, and interobserver variability was assessed. RESULTS: Mean sensitivity and specificity of the 2 readers for the depiction of inflammatory lesions were 78.4%/100% using ce-T1-w MRC, 95.2%/100% using DWI, and 93.5%/100% combining both imaging techniques compared with colonoscopy including results of the histopathological samples. In 6 patients, inflammatory lesions were only detected by DWI; in another 6 patients, DWI detected additional lesions. The κ values for the 2 readers were excellent (k = 0.92-0.96). The preferred b value with the best detectability of the lesion was b1000 in 28 of the 30 patients (93.3%) with restricted diffusion. CONCLUSIONS: Diffusion-weighted imaging of the bowel identified inflammatory lesions with high accuracy and revealed lesions that were not detectable with ce-T1-w imaging alone. A b value of 1000 showed the best lesion detectability.

Motility mapping as evaluation tool for bowel motility: initial results on the development of an automated color-coding algorithm in cine MRI.

PURPOSE: To develop and implement an automated algorithm for visualizing and quantifying bowel motility using cine magnetic resonance imaging (MRI). MATERIALS AND METHODS: Four healthy volunteers as well as eight patients with suspected or diagnosed inflammatory bowel disease (IBD) underwent MR examinations on a 1.5T scanner. Coronal T2-weighted cine MR images were acquired in healthy volunteers without and with intravenous (i.v.) administration of butylscopolamine. In patients with IBD, cine MRI sequences were collected prior to standard bowel MRI. Bowel motility was assessed using an optical flow algorithm. The resulting motion vector magnitudes were presented as bowel motility maps. Motility changes after i.v. administration of butylscopolamine were measured in healthy volunteers. Inflamed bowel segments in patients were correlated with motility map findings. RESULTS: The acquisition of bowel motility maps was feasible in all subjects examined. In healthy volunteers butylscopolamine led to quantitatively measurable decrease in bowel motility (mean decrease of 59%; P = 0.171). In patients with IBD, visualization of bowel movement by color-coded motility mapping allowed for the detection of segments with abnormal bowel motility. Inflamed bowel segments could be identified by exhibiting a decreased motility. CONCLUSION: Our method is a feasible and promising approach for the assessment of bowel motility disorders.

Improved detection of inflammatory bowel disease by additional automated motility analysis in magnetic resonance imaging.

OBJECTIVES: The objective of this study was to evaluate whether the use of automatically generated maps of bowel motility (motility mapping) in magnetic resonance imaging (MRI) leads to an increased detection rate of inflammatory bowel disease. MATERIALS AND METHODS: Fifty consecutive patients with suspected or known inflammatory bowel disease who underwent bowel MRI using a 1.5-T scanner were analyzed retrospectively. In addition to standard small bowel magnetic resonance protocol, a dynamic coronal T2-weighted sequence (dynamic MRI) was acquired. Dynamic sequences were used to automatically generate a parametric map depicting bowel motility. Two readings of the MRI were performed: first, evaluation of static MRI alone and second, evaluation of static MRI combined with dynamic MRI (motility mapping). Static MRI was analyzed on parameters defining inflammation (morphology, enhancement). Dynamic MRI (motility mapping) was evaluated on the basis of a color-coded scheme displaying hypomotility and hypermotility. RESULTS: Using motility maps, additional inflammatory lesions were found in 13 (26%) of the 50 patients, resulting in a significantly higher detection rate using static MRI together with motility mapping compared with static MRI alone (P = 0.0002). Overall, 66 inflammatory lesions of the bowel were detected in a total of 38 patients (static MRI + motility mapping) versus 51 lesions in 34 patients (sole evaluation of static MRI). CONCLUSIONS: Motility assessment of the bowel provides additional information and improves the detection of inflammatory lesions in MRI.