Periportal edema in trauma patients: correlation with trauma severity.

BACKGROUND: Periportal edema (PPE) can be seen in different clinical settings, including in patients following trauma. However, the underlying mechanisms and clinical significance in trauma patients still remain unclear. PURPOSE: To determine the incidence of PPE in CT scans of trauma patients and to correlate PPE with trauma severity and different patterns of injury. MATERIAL AND METHODS: We retrospectively analyzed contrast-enhanced spiral CT scans of 127 trauma patients that were referred to our Trauma Center Level I between January 2006 and June 2007. According to the Injury Severity Score (ISS), 70 patients with an ISS < 16 (minor trauma) were assigned to group 1 and 57 patients with an ISS ≥16 (major trauma) to group 2. RESULTS: The presence of PPE was significantly (p < 0.01) higher in group 2 (22 of 57 patients [38.6%]) than in group 1 (10 of 70 patients [14.3%]). In 29 patients PPE presented with a diffuse pattern and in three patients with a focal pattern, affecting only one liver lobe. In 14 patients PPE was found in absence of abdominal injuries. In addition, PPE was present in five patients with abdominal injuries but without liver injury. CONCLUSION: PPE is seen significantly more often on abdominal CT scans following major traumas (ISS ≥ 16), but is not necessarily associated with liver injury.

CT-scan is a valuable tool to detect mandibular involvement in oral cancer patients.

In patients with oral squamous cell carcinomas (OSSC) it is desirable to avoid unnecessary bone resection without neglecting the overall surgical treatment goal of tumor-free margins. Whereas computed tomography (CT) is most commonly used to detect mandibular invasion, there are conflicting reports regarding the accuracy of CT. Therefore, the aim of this study was to reinvestigate the accuracy of CT in predicting mandibular involvement by OSSC. One hundred and seven patients with OSSC who received a mandibulectomy were included. Before treatment all patients underwent a contrast-enhanced multi-detector CT. Axial 3 or 1.25 mm thick images were reconstructed for evaluation in overlapping technique and displayed in a bone (1400/400 HU) and a soft tissue window (350/50 HU). CT scans were examined by three investigators and compared with the histological findings. The radiological examination showed a high interrater reliability (Cronbachs alpha 0.982). Comparing the radiological findings with the histological results the CT showed 8 false-positive results and 8 false-negative patients. The quality criteria for detecting bone involvement of OSSC by CT were calculated as follows: sensitivity 82.6%; specificity 86.9%; positive predictive value 82.6%; negative predictive value 86.9%. However, in all false-positive patients a sagittal bone defect of 15.1mm could be found presumably caused by pressure of the tumor, but no histologically detectable bone infiltration. Modern CT (1-2 mm sections) is a valuable tool for surgical treatment planning. If bone invasion is detected, a mandibulectomy seems always reasonable. In radiologically negative cases histological assessment is necessary to detect mandibular involvement.

Temporally resolved electrocardiogram-triggered diffusion-weighted imaging of the human kidney: correlation between intravoxel incoherent motion parameters and renal blood flow at different time points of the cardiac cycle.

PURPOSE: To evaluate the influence of pulsatile blood flow on apparent diffusion coefficients (ADC) and the fraction of pseudodiffusion (F(P)) in the human kidney. MATERIALS AND METHODS: The kidneys of 6 healthy volunteers were examined by a 3-T magnetic resonance scanner. Electrocardiogram (ECG)-gated and respiratory-triggered diffusion-weighted imaging (DWI) and phase-contrast flow measurements were performed. Flow imaging of renal arteries was carried out to quantify the dependence of renal blood flow on the cardiac cycle. ECG-triggered DWI was acquired in the coronal plane with 16 b values in the range of 0 s/mm(2) and 750 s/mm(2) at the time of minimum (MIN) (20 milliseconds after R wave) and maximum renal blood flow (MAX) (197 ± 24 milliseconds after R wave). The diffusion coefficients were calculated using the monoexponential approach as well as the biexponential intravoxel incoherent motion model and correlated to phase-contrast flow measurements. RESULTS: Flow imaging showed pulsatile renal blood flow depending on the cardiac cycle. The mean flow velocity at MIN was 45 cm/s as compared with 61 cm/s at MAX. F(p) at MIN (0.29) was significantly lower than at MAX (0.40) (P = 0.001). Similarly, ADC(mono), derived from the monoexponential model, also showed a significant difference (P < 0.001) between MIN (ADC(mono) = 2.14 ± 0.08 × 10(-3) mm(2)/s) and MAX (ADC(mono) = 2.37 ± 0.04 × 10(-3) mm(2)/s). The correlation between renal blood flow and F(p) (r = 0.85) as well as ADC(mono) (r = 0.67) was statistically significant. CONCLUSION: Temporally resolved ECG-gated DWI enables for the determination of the diffusion coefficients at different time points of the cardiac cycle. ADC(mono) and FP vary significantly among acquisitions at minimum (diastole) and maximum (systole) renal blood flow. Temporally resolved ECG-gated DWI might therefore serve as a novel technique for the assessment of pulsatility in the human kidney.