CT of the medial clavicular epiphysis for forensic age estimation: hands up?

PURPOSE: The aim of this study was to assess the impact of arm position in computed tomography (CT) of the clavicle performed for forensic age estimation on clavicular position, image noise, and radiation dose. METHODS AND MATERIALS: Forty-seven CT scans of the medial clavicular epiphysis performed for forensic age estimation were conducted with either hands and arms held upwards (CTHU, 28 persons) or positioned at the body (CTHD, 19 persons). Presets were identical for both positions (70 mAs/140 kVp; Brilliance iCT, Philips). Each CT scan was reconstructed with an iterative algorithm (i-Dose 4) and evaluated at the middle of the sternoclavicular joint. Clavicular angle was measured on a.p. topograms in relation to a horizontal line. Quantitative image noise was measured in air at the level of medial clavicular epiphysis. Effective dose and scan length were recorded. RESULTS: Hands-up position compared with hands-down position resulted in a lower lateral body diameter (CTHU 41.1 ± 3.6 cm vs. CTHD 44.6 ± 3.1 cm; P = 0.03), a reduced quantitative image noise (CTHU: 39.5 ± 9.2; CTHD: 46.2 ± 8.3; P = 0.02), and lower CTDIvol (5.1 ± 1.4 mGy vs. 6.7 ± 1.8 mGy; P = 0.001). Scan length was longer in patients examined with hands up (HU: 8.5 ± 3.4 cm; HD: 6.2 ± 2.1 cm; P = 0.006). Mean effective dose for CTHU was 0.79 ± 0.32 mSv compared with 0.95 ± 0.38 mSv in CTHD (P = 0.12). Clavicular angle was 17° ± 6° in patients with hands down and 32° ± 7° in patients with hands up (P < 0.001). CONCLUSION: By elevated arm positioning, the image quality of clavicular CT scans can be improved while maintaining radiation dose compared with hands down. Clavicular position differs according to the hand position. Thus, positioning patients with elevated hands is advisable for forensic clavicular CT examinations, but multiplanar CT reconstructions should be adjusted to clavicular position and scan length should be reduced to a minimum.

Comparison of different iterative CT reconstruction techniques and filtered back projection for assessment of the medial clavicular epiphysis in forensic age estimation.

PURPOSE: To assess the impact of iterative reconstruction and filtered back projection (FBP) on image quality in computed tomography (CT)-based forensic age estimation of the medial clavicular epiphysis. METHODS AND MATERIALS: CT of the clavicle was performed in 19 patients due to forensic reasons (70 mAs/140 kVp). Raw data were reconstructed with FBP and with an iterative algorithm at level 4 and 6. Clavicular ossification stage was determined by two radiologists in consensus, firstly on FBP reconstructed images and secondly after reviewing all reconstructions including iDose 4 and 6. In addition, the 3 reconstructions were compared regarding artefacts and delineation of the meta-/epiphyseal interface. Quantitative image noise was measured. RESULTS: Quantitative noise was lower in iDose 6 reconstructed images than in FBP (P < 0.042), but not significantly lower between iDose 4 and FBP (P = 0.127). Side by side comparison revealed lesser qualitative image noise on both iDose reconstructed images than for FBP. The meta-/epiphyseal interface delineation was rated better on both iDose levels than with FBP. In 3 of 19 patients, the clavicular ossification stage was reclassified after iterative reconstructions had been additionally reviewed. CONCLUSION: Using iterative CT reconstruction algorithms, a reduction of image noise and an enhancement of image quality regarding the meta-/epiphyseal clavicular interface can be achieved. The study highlights the importance of image standardization as variation of reconstruction technique has impact on forensic age estimation.

Persistence of post-operative color Doppler abnormalities is linked to reduced graft survival in pediatric patients after liver transplantation.

Color Doppler US is a readily available imaging modality for the evaluation of liver transplants. The aim of our study was to evaluate the temporal course of color Doppler US findings in children after LTX and to investigate the effect of resolving and persisting abnormalities during follow-up on long-term outcome. All children who underwent LTX during January 2000 until December 2003 (155 LTX in 137 patients, 75 male and 62 female; mean age at LTX 4.1 ± 4.8 years; range, 0.1-16.3 years) were retrospectively evaluated. Following a predefined ultrasound protocol with prospective documentation, intraoperative, post-operative, and follow-up examinations were evaluated for color Doppler abnormalities. The time of occurrence and temporal course of the findings were recorded. Graft survival rates and graft survival times were compared. Abnormal color Doppler US examinations were noted in 98 of 155 grafts during the entire observational period (63.2%). In 57 of 98 grafts (58.2%), abnormalities were limited to the perioperative period (<30 days after LTX). Survival of grafts with transient perioperative abnormalities was similar to transplantations with regular color Doppler US examinations (graft survival rates, 80.7% vs 84.2%, P = .622; mean graft survival time, 2596.92 vs 2511.40 days, P = .67). Grafts with persisting color Doppler US abnormalities in the follow-up period (>30 days after LTX; 37/98 LTX, 37.8%) showed reduced survival compared with regular courses (graft survival rate 62.2% vs 80.7%, P = .047), indicating underlying organ-specific alterations. Standardized longitudinal evaluation during the perioperative and the follow-up period can enhance the prognostic capabilities of color Doppler US in children following LTX.

Diffusion-weighted imaging of the kidneys in haemolytic uraemic syndrome.

OBJECTIVES: To evaluate the kidneys of patients with haemolytic uraemic syndrome (HUS) using diffusion-weighted imaging (DWI) and Doppler ultrasound (US) compared with healthy controls. MATERIALS AND METHODS: Fifteen patients (mean age 33.3 years; three male; 12 female) with diarrhoea-positive HUS and 15 healthy volunteers were prospectively evaluated with DWI and Doppler US. A total apparent diffusion coefficient (ADCTOT), and ADCs predominantly reflecting microperfusion (ADCLOW) and diffusion (ADCHIGH) were calculated. Doppler US evaluated renal vascularity and flow. RESULTS: When compared with controls, kidneys affected by HUS showed reduced cortical ADC values (ADCTOT 1.79±0.22 vs. 2.04±0.1x10-3 mm2/s, P 0.001), resulting in either low corticomedullary differences (11/15 patients) or an inverted corticomedullary pattern (4/15 patients). Reduction of cortical ADC values was associated with a decrease of cortical vascularity on Doppler US (ADCTOT, P<0.001; ADCLOW, P 0.047). Kidneys with complete absence of the cortical vasculature on Doppler US (four patients) also demonstrated limited diffusion (ADCHIGH, P 0.002). Low glomerular filtration rate, requirement for haemodialysis during hospitalization, and longer duration of haemodialysis were associated with decreased cortical diffusivity (ADCTOT: P 0.04, 0.007, and <0.001, respectively). CONCLUSION: DWI shows qualitative and quantitative abnormalities in kidneys affected by HUS, thereby extending the non-invasive assessment of renal parenchymal damage. KEY POINTS: • In HUS, DWI is feasible for functional characterization of kidney involvement. • Kidneys affected by HUS showed reduced cortical diffusivity. • Decreased cortical diffusivity was associated with lower kidney function. • Requirement and duration of haemodialysis was linked to degree of cortical alterations.

Transcapsular arterial neovascularization of liver transplants increases the risk of intraoperative bleeding during retransplantation.

Arterial neovascularization of liver grafts can be a source of significant blood loss during retransplantation. This study evaluated the effect of transcapsular arterial neovascularization on intraoperative blood loss during retransplantation and long-term follow-up. Eleven consecutive patients with transcapsular arterial neovascularization (seven male, four female; nine children, two adults; mean age 12.3 ± 16.3 years) and the same number of matched control patients were analysed. Blood loss was calculated based on transfusion requirements. The volume of transfused units of red blood cells per kilogram bodyweight until hepatectomy and during the entire procedure was significantly higher in patients with neovascularization than in control patients (0.32 ± 0.21 vs. 0.14 ± 0.11, and 0.94 ± 0.83 vs. 0.36 ± 0.38 respectively; P-values 0.027). Neovascularization was associated with extensive intra-abdominal adhesions and a longer operating time until hepatectomy (175.6 ± 52.1 min vs. 124.3 ± 34.9 min, P-value 0.015). Postoperative revisions were performed more frequently in patients with neovessels. Graft survival did not differ between groups. Assessment for transcapsular arterial neovascularization should be included in preoperative Doppler ultrasound protocols to identify patients at risk of a complicated intra- and postoperative course in case of retransplantation.

Diffusion-weighted imaging of the healthy pancreas: ADC values are age and gender dependent.

PURPOSE: To investigate the healthy pancreas with diffusion-weighted imaging (DWI) for characterization of age and gender-related differences in apparent diffusion coefficient (ADC) values. MATERIALS AND METHODS: Sixty six volunteers were prospectively enrolled (33 male, 33 female; range 1.4 to 83.7 years of age) and echo-planar DWI of the pancreas was performed. ADC values were measured in the pancreas head, body, and tail using a pixel-by-pixel approach. Effects of age and gender on ADC values were analyzed using a two-factorial multivariate analysis of variance (MANOVA). RESULTS: ADC values correlated inversely with the age of the volunteers. The mean global pancreatic ADC values (× 10(-3) mm(2)/s) in the age groups 0-20 years, 21-40 years, and > 40 years were 1.18 ± 0.19, 1.07 ± 0.13, and 0.99 ± 0.18, respectively. Female individuals had higher mean global ADC values than male (1.13 ± 0.14 versus 1.02 ± 0.18 × 10(-3) mm(2)/s). MANOVA showed significant effects of age (P value 0.022, eta(2) = 0.13) and gender (P value 0.001, eta(2) = 0.28) on ADC values. CONCLUSION: Pancreatic ADC values decline with ageing and show significant gender differences with higher mean values in females. The awareness of baseline values adjusted to age and gender will be important for correct interpretation of individual cases and design of future studies.

Diffusion-weighted imaging of the healthy pancreas: apparent diffusion coefficient values of the normal head, body, and tail calculated from different sets of b-values.

PURPOSE: To evaluate differences in apparent diffusion coefficient (ADC) values between head, body, and tail regions and the impact of sets of b-values used in diffusion weighted imaging (DWI) of the normal pancreas. MATERIALS AND METHODS: In 51 healthy volunteers echo-planar DWI of the pancreas was prospectively performed with b-values of 50, 400, and 800 s/mm(2) . All four possible combinations of b-values were used to calculate ADC values in a total of 587 regions in the pancreas head, body, and tail regions. Dependency of ADC values on the anatomical regions and on the applied sets of b-values was calculated using multivariate analysis of variance (ANOVA). RESULTS: Mean ADC values differed significantly between the anatomical regions with the lowest values measured in the pancreatic tail (head 1.13 ± 0.20, body 1.05 ± 0.20, and tail 0.94 ± 0.18 × 10(-3) mm(2) /s; P < 0.05). ANOVA showed no dependency of ADC values on the sets of b-values used. CONCLUSION: ADC values differed significantly between the pancreatic head, body, and tail region, with decreasing ADC values toward the tail. Cautious interpretation of DWI results with adjusted, normalized values adapted to the anatomical region seems advisable. The knowledge of such differences may enhance the method's capability to differentiate between different pancreatic pathologies.

Transcapsular arterial neovascularization after liver transplantation in pediatric patients indicates transplant failure.

PURPOSE: To identify transcapsular arterial neovascularization with Doppler ultrasonography (US) in pediatric patients after liver transplantation and to assess the frequency of the finding, its underlying causes, and its relevance in terms of clinical outcome. MATERIALS AND METHODS: The study was approved by the local ethics committee, with waived informed consent. All pediatric patients who underwent liver transplantation between January 2000 and December 2003 were retrospectively evaluated. Patients were followed up until June 2008, by using a predefined US protocol with prospective documentation. Of 182 consecutive liver transplantations performed in 162 patients (mean age, 4.5 years; range, 0.1-18.4 years) in this period, 25 patients with a total of 27 liver transplantations underwent US examinations conducted by multiple investigators and were primarily excluded. Student t tests and χ(2) tests were performed where appropriate. The Tarone-Ware test was used to compare transplant survival times. RESULTS: Transcapsular arterial neovascularization was noticed in 13 of 137 patients (9.5%) and in 13 of 155 liver transplants (8.4%). The mean time until arterial neovessels appeared was 157 days after liver transplantation (median, 97 days; range, 19-477 days). Arterial neovascularization was associated with pronounced transplant malperfusion and inflammatory changes (P < .001). Patients with transcapsular arterial neovascularization had a significantly shorter mean transplant survival time (1426.4 days ± 244.5 [standard error], with 95% confidence interval: 947.23, 1905.23, vs 2526.4 days ± 92.1, with 95% confidence interval: 2345.84, 2706.97; P = .008) and a higher retransplantation rate (53.8% vs 19.7%, P = .009). CONCLUSION: Transcapsular arterial neovascularization, detected with color Doppler US, occurred in 9.5% (13 of 137) of pediatric patients and 8.4% (13 of 155) of liver transplants and was associated with underlying malperfusion and inflammation. The diagnosis of transcapsular arterial neovascularization was associated with reduced graft survival times and a high retransplantation rate. The negative prognostic value of the sign may assist in a strategy of organ allocation.