[en] The aim of this study is to compare a qualitative and a quantitative assessment of brain diffusion-weighted imaging (DWI) in predicting outcome of comatose patients after cardiac arrest (CA). Two observers used a scoring template to analyze the DWI of 75 patients. A total of 13 regions were scored from 0 to 3 (0 = normal, 1 = probably normal, 2 = probably abnormal, 3 = definitely abnormal). The total cerebral cortex (TCC), the total deep grey nuclei (TDGN), the total brain stem, the total cerebellum, and the total brain score were calculated. Intra- and inter-observer variability were tested. The mean whole brain apparent diffusion coefficient (ADC) values and percentage of voxels below a specific ADC value cut-off were calculated. The data were correlated with clinical outcome (cerebral performance category score after 180 days, dichotomized in a score 1–2 with favorable outcome and score 3–5 with unfavorable outcome) using ROC analysis. Intra-observer variability was excellent for the TCC score (ICC 0.95 and 0.86) and the TDGN score (ICC 0.89 and 0.75). Inter-observer variability was good to excellent for total cerebral cortex score and total deep grey nuclei score in both the first (ICC 0.78 and 0.69) and third (ICC 0.86 and 0.83) image assessment. TCC and TDGN score show the best correlation with clinical outcome (highest AUC values 0.87 and 0.87). Quantitative parameters did not show good correlation with clinical outcome (AUC values 0.57 and 0.60). A qualitative assessment of brain DWI using a scoring template provides useful data regarding patient outcome while quantitative data appeared less reliable.

[en] To examine the feasibility and results of calculating the volume of lumbar vertebral bodies in normal patients and patients with suspected hypoplasia of L5. Lumbar multi-detector CT was performed in 38 patients with bilateral spondylolysis and hypoplasia of L5 and in 38 normal patients. Lumbar vertebral body volume of L3, L4 and L5 was measured by CT volumetry with a semi-automated program, created with MeVisLab. In the control group, the average vertebral body volume (in cubic centimeters) of L3 was 35.93 (±7.33), 36.34 (±7.13) for L4 and 34.63 (±6.88) for L5. In patients with suspected hypoplasia L5 the average body volume (in cubic centimeters) of L3 was 36.85 (±7.37), 36.90 (±6.99) for L4 and 33.14 (±6.57) for L5. The difference in mean vertebral body volume for L3, L4 and L5 between both groups was statistically not significant. However, there was a statistically significant difference of the ratio L5/L4 (P < 0.001) between both groups: the mean ratio L5/L4 in the control group was 95.3 ± 3.9%, the ratio for the hypoplastic L5 group was 89.9 ± 6.3%. There was no significant difference in the vertebral body volume for L3, L4 and L5 between both groups due to inter-patient variability. However, the relation between the body volume of L5 and L4 is significantly different between both groups. The volume of the vertebral body of L5 proved to be on average 10.2% smaller than the volume of L4 in the group with hypoplasia L5 versus 4.7% in the control group. (orig.)

[en] Diffusion-weighted MRI has become more and more popular in the last couple of years. It is already an accepted diagnostic tool for patients with acute stroke, but is more difficult to use for extracranial applications due to technical challenges mostly related to motion sensitivity and susceptibility variations (e.g., respiration and air-tissue boundaries). However, thanks to the newer technical developments, applications of body DW-MRI are starting to emerge. In this review, we aim to provide an overview of the current status of the published data on DW-MRI in extracranial applications. A short introduction to the physical background of this promising technique is provided, followed by the current status, subdivided into three main topics, the functional evaluation, tissue characterization and therapy monitoring. (orig.)

[en] In the head and neck, squamous cell carcinoma is one of the most common tumour types. Currently, the primary imaging modalities for initial locoregional staging are computed tomography and - to a lesser extent - magnetic resonance imaging, whilst [¹⁸F]fluorodeoxyglucose (FDG) positron emission tomography has additional value in the detection of subcentimetric metastatic lymph nodes and of tumour recurrence after chemoradiotherapy (CRT). However, dependency on the morphological and size-related criteria of anatomical imaging and the limited spatial resolution and FDG avidity of inflammation in metabolic imaging may reduce diagnostic accuracy in the head and neck. Diffusion-weighted magnetic resonance imaging (DWI) is a noninvasive imaging technique that measures the differences in water mobility in different tissue microstructures. Water mobility is likely influenced by cell size, density, and cellular membrane integrity and is quantified by means of the apparent diffusion coefficient. As such, the technique is able to differentiate tumoural tissue from normal tissue, inflammatory tissue and necrosis. In this article, we examine the use of DWI in head and neck cancer, focussing on technique optimization and image interpretation. Afterwards, the value of DWI will be outlined for clinical questions regarding nodal staging, lesion characterization, differentiation of post-CRT tumour recurrence from necrosis and inflammation, and predictive imaging towards treatment outcome. The possible consequences of adding DWI towards therapeutic management are outlined. (orig.)

[en] The purpose of this study was to evaluate the accuracy of diffusion-weighted magnetic resonance imaging (DW-MRI) in differentiating HCC from benign cirrhotic lesions compared with conventional dynamic contrast-enhanced MRI. Fifty-five patients with cirrhosis underwent conventional and DW-MRI at 1.5 Tesla. Signal intensity ratios (SI_ratio) of solid liver lesions to adjacent hepatic parenchyma were measured for b0, b100, b600 and b1000, and the apparent diffusion coefficients (ADC) were calculated. In 27 patients, imaging results were compared to histopathology, and in 28 patients, to imaging follow-up. Based on predetermined thresholds, sensitivity and specificity of DW-MRI and conventional MRI were compared. SI_ratio was significantly different between malignant and benign lesions at all b-values (P<0.0001). No significant difference in ADC was seen (P = 0.47). For detection of malignant lesions, DW-MRI with b600-SI_ratio yielded a sensitivity of 95.2% compared to 80.6% for conventional MRI (P = 0.023) and a specificity of 82.7% compared to 65.4% (P=0.064). The improved accuracy was most beneficial for differentiating malignant lesions smaller than 2 cm. DW-MRI with b600-SI_ratio improved the detection of small HCC and the differentiation of pseudotumoral lesions compared with conventional MRI. (orig.)

[en] To evaluate effects of a vascular-disrupting agent on rodent tumour models. Twenty rats with liver rhabdomyosarcomas received ZD6126 intravenously at 20 mg/kg, and 10 vehicle-treated rats were used as controls. Multiple sequences, including diffusion-weighted imaging (DWI) and dynamic contrast-enhanced MRI (DCE-MRI) with the microvascular permeability constant (K), were acquired at baseline, 1 h, 24 h and 48 h post-treatment by using 1.5-T MRI. [¹⁸F]fluorodeoxyglucose micro-positron emission tomography (¹⁸F-FDG μPET) was acquired pre- and post-treatment. The imaging biomarkers including tumour volume, enhancement ratio, necrosis ratio, apparent diffusion coefficient (ADC) and K from MRI, and maximal standardised uptake value (SUV_max) from FDG μPET were quantified and correlated with postmortem microangiography and histopathology. In the ZD6126-treated group, tumours grew slower with higher necrosis ratio at 48 h (P < 0.05), corresponding well to histopathology; tumour K decreased from 1 h until 24 h, and partially recovered at 48 h (P < 0.05), parallel to the evolving enhancement ratios (P < 0.05); ADCs varied with tumour viability and perfusion; and SUV_max dropped at 24 h (P < 0.01). Relative K of tumour versus liver at 48 h correlated with relative vascular density on microangiography (r = 0.93, P < 0.05). The imaging biomarkers allowed morphological, functional and metabolic quantifications of vascular shutdown, necrosis formation and tumour relapse shortly after treatment. A single dose of ZD6126 significantly diminished tumour blood supply and growth until 48 h post-treatment. (orig.)

[en] To evaluate diffusion-weighted (DWI) magnetic resonance imaging (MRI) for treatment prediction during chemoradiotherapy (CRT) of head and neck squamous cell carcinoma (HNC). Thirty patients with HNC underwent echo-planar DWI and anatomical MRI before and 2 and 4 weeks into CRT. Patient follow-up lasted 2 years post-CRT. Tumour ADC (ΔADC) and volume changes (ΔV) between baseline, and 2 and 4 weeks' follow-up were compared for lesions with recurrence versus complete remission (CR) using a Mann-Whitney U test. The predictive value of the ΔADC and ΔV for locoregional control (LRC) was examined with the Kaplan-Meier method. The study was approved by the local ethics committee. All patients gave written informed consent. The ΔADC in primary tumours and nodal metastases, 2 and 4 weeks after the start of CRT, was significantly lower in lesions with post-CRT recurrence than in lesions with CR (ΔADC_2weeks and ΔADC_4weeks for primary tumours, relative to nodal metastases: p < 0.0001). The ΔV only showed a significant difference for primary tumours at 2 weeks (ΔV_2weeks: p = 0.03). The ΔADC correlated significantly with 2-year LRC (p < 0.001); the ΔV did not (p > 0.05). DWI during CRT for HNC allows more accurate response prediction than anatomical imaging, correlating significantly with 2-year LRC. (orig.)

[en] To assess whether diffusion-weighted magnetic resonance imaging (DW-MRI) including bi-exponential fitting helps to detect residual/recurrent tumours after (chemo)radiotherapy of laryngeal and hypopharyngeal carcinoma. Forty-six patients with newly-developed/worsening symptoms after (chemo)radiotherapy for laryngeal/hypopharyngeal cancers were prospectively imaged using conventional MRI and axial DW-MRI. Qualitative (visual assessment) and quantitative analysis (mono-exponentially: total apparent diffusion coefficient [ADC_T], and bi-exponentially: perfusion fraction [F_P] and true diffusion coefficient [ADC_D]) were performed. Diffusion parameters of tumour versus post-therapeutic changes were compared, with final diagnosis based on histopathology and follow-up. Mann-Whitney U test was used for statistical analysis. Qualitative DW-MRI combined with morphological images allowed the detection of tumour with a sensitivity of 94% and specificity 100%. ADC_T and ADC_D values were lower in tumour with values 120 ± 49 x 10^-5 mm²/s and 113 ± 50 x 10^-5 mm²/s, respectively, compared with post-therapeutic changes with values 182 ± 41 x 10^-5 mm²/s (P < 0.0002) and 160 ± 47 x 10^-5 mm²/s (P < 0.003), respectively. F_P values were significantly lower in tumours than in non-tumours (13 ± 9% versus 31 ± 16%, P < 0.0002), with F_P being the best quantitative parameter for differentiation between post-therapeutic changes and recurrence. DW-MRI in combination with conventional MRI substantially improves detection and exclusion of tumour in patients with laryngeal and hypopharyngeal cancers after treatment with (chemo)radiotherapy on both qualitative and quantitative analysis, with F_P being the best quantitative parameter in this context. (orig.)

[en] We sought to establish and characterize a mouse liver tumor model as a platform for preclinical assessment of new diagnostics and therapeutics. Radiation-induced fibrosarcoma (RIF-1) was intrahepatically implanted in 27 C3H/Km mice. Serial in vivo magnetic resonance imaging (MRI) with a clinical 1.5-T-magnet was performed using T1- (T1WI), T2- (T2WI), and diffusion-weighted sequences (DWI), dynamic contrast-enhanced MRI (DCE-MRI), and contrast-enhanced T1WI, and validated with postmortem microangiography and histopathology. Implantation procedure succeeded in 25 mice with 2 deaths from overdosed anesthesia or hypothermia. RIF-1 grew in 21 mice with volume doubling time of 2.55±0.88 days and final size of 216.2±150.4 mm³ at day 14. Three mice were found without tumor growth and one only with abdominal seeding. The intrahepatic RIF-1 was hypervascularized with negligible necrosis as shown on MRI, microangiography and histology. On DCE-MRI, maximal initial slope of contrast-time curve and volume transfer constant per unit volume of tissue, K, differed between the tumor and liver with only the former significantly lower in the tumor than in the liver (P<0.05). Liver implantation of RIF-1 in mice proves a feasible and reproducible model and appears promising for use to screen new diagnostics and therapeutics under noninvasive monitoring even with a clinical MRI system. (orig.)

[en] The purpose of this study was to retrospectively assess the incidence of bowel wall oedema on computed tomography (CT) in patients with renal cell carcinoma (RCC) treated with sunitinib, and to investigate its association with diarrhoea. We conducted a retrospective analysis of all RCC patients treated with sunitinib at our hospital between December 2005 and December 2011. The presence or absence of bowel wall oedema on these CT examinations was scored. The presence of diarrhoea preceding, during, or after sunitinib treatment was identified from the patient files and retrospectively graded. For 54 of 87 patients, bowel wall oedema was present on at least one CT examination. Of these 54 patients, the right-sided colonic segment was affected in 87 %. Diarrhoea was the most common reported adverse event during treatment, with 58 patients (67 %) having grade 1/2 diarrhoea and 9 patients (10 %) having grade 3. There was a statistically significant correlation between the incidence of CT-scored bowel oedema and diarrhoea during sunitinib treatment (P = 0.004). This study shows a very high incidence of bowel wall oedema and a strong correlation between the incidence of bowel wall oedema and diarrhoea in patients treated with sunitinib. (orig.)