B-0721 CT imaging in an emergency setting is not substantially delayed by iterative reconstruction

M.J. Willemink, A.M.R. Schilham, T. Leiner, W.P.T.M. Mali, P.A. de Jong, R.P.J. Budde | Sunday, March 10, 10:30 – 12:00 / Room N/O

Purpose: Iterative reconstruction (IR) is a promising noise reducing technique with the potential to reduce radiation-dose with preserved study interpretability or improve image-quality at similar radiation-dose. One of the major drawbacks of IR is a longer reconstruction time which may be problematic in the emergency setting. The purpose of the current study was to compare reconstruction time and speed of IR and filtered back-projection (FBP) in two commonly encountered emergency imaging scan-protocols: total body trauma CT and pulmonary CTA.
Methods and Materials: Fifteen patients underwent a total body CT after a traumatic event and twenty-five adults underwent a CTA for evaluation of pulmonary embolisms on a 256-slice CT-scanner. All data were reconstructed using FBP and two IR-levels (iDose⁴, Philips Healthcare). Quantification of reconstruction time and speed was done with a self-written plug-in for ImageJ (US National Institutes of Health).
Results: The mean delay in reconstruction time on total body trauma CTs was 44.4±8.1 and 44.9±7.0 seconds for iDose⁴-levels 1 and 6, respectively, and on pulmonary CTAs 10.1±9.6 and 12.0±11.8 seconds for iDose⁴-levels 2 and 4, respectively. The mean reconstruction time and speed for total body trauma CTs were 87.3±14.6, 131.7±16.7 and 132.2±17.9 seconds, and 20.1±1.6, 13.2±0.8 and 13.2±0.6 slices/s for FBP, iDose⁴-levels 1 and 6, respectively, and for pulmonary CTAs 25.5±7.0, 35.6±9.0 and 37.6±12.0 seconds, and 26.7±5.6, 18.7±2.3 and 18.0±2.8 slices/s for FBP, iDose⁴-levels 2 and 4, respectively.
Conclusion: CT image reconstruction in an emergency setting is not delayed substantially by IR. Furthermore, reconstruction time and speed did not differ substantially between different IR-levels.

MS 4 – Hepatocellular carcinoma

B. Sangro, A. Benito, J.I. Bilbao, F. Pardo | Friday, March 8, 08:30 – 10:00 / Room F1

A-075 Chairman’s introduction

A variety of options are available for the treatment of hepatocellular carcinoma (HCC) from liver transplantation or resection to percutaneous ablation by chemical or physical procedures, intraarterial injection of embolizing particles that may also serve as carriers of chemotherapeutic agents or radiation-emitting isotopes, or systemic delivery of molecularly targeted agents. Although large scale studies have identified groups of patients that may certainly benefit from some of these therapeutic tools, many areas of uncertainty still exist. Only by the coordinated action of HPB Oncology multidisciplinary teams may patients with HCC receive the best possible treatment.

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B-0949 MRI-based selection of clinical complete and good responders after chemoradiation for rectal cancer allows for successful minimal invasive treatment

L. Heijnen, M. Maas, M.H. Martens, D.M.J. Lambregts, J.W.A. Leijtens, R.G.H. Beets-Tan, G.L. Beets | Monday, March 11, 14:00 – 15:30 / Room E2

Purpose: Patients with good or complete response after neoadjuvant chemoradiation have excellent long-term outcome. Minimal invasive treatment (i.e. transanal endoscopic microsurgery (TEM) and wait-and-see policy) are increasingly considered as an alternative to major surgery. With this prospective cohort study we aimed to evaluate long-term outcome of strictly MR-based selected patients who have been treated with minimal invasive treatment.
Methods and Materials: Eight weeks after chemoradiation, endoscopy and restaging MRI were performed (including diffusion-weighted MRI for yT-staging and gadofosveset-enhanced MRI for yN-staging). Complete responders were selected for wait-and-see policy and good responders with small tumour remnant for TEM. Both treatment groups underwent intensive 3-to-6 monthly follow-up, using MR imaging (DWI+gadofosveset), CEA, CT of thorax and abdomen and endoscopy was performed. Long-term outcome was estimated with Kaplan-Meier curves.
Results: Forty-one patients were included, thirty-three in the wait-and-see group and eight in the TEM-group. Mean follow-up was 26 months (range 6-91). For the TEM-group, 4 patients had ypT0 and 4 had ypT2. Two patients, both in the wait-and-see group, developed a local recurrence within two years and underwent surgery, leading to a 2-year local recurrence rate of 9 %. Both recurrences were detected on (DWI-)MRI in an early stage. The cumulative probabilities of 2-year disease-free survival and overall survival were 93 % and 100 %, respectively. No recurrences occurred in the TEM-group.
Conclusion: Both selection and follow-up of good and complete responders after chemoradiation for rectal cancer with MRI is feasible. Long-term outcome so far is excellent. (DWI-)MRI seems to be a reliable tool for early recurrence detection.

B-0816 Breast tomosynthesis versus digital mammography: evaluation of diagnostic potential in women with abnormal screening mammograms

M. Mohamed Aly | Monday, March 11, 10:30 – 12:00 / Room F2

Purpose: To compare the diagnostic potential of digital mammography with tomosynthesis.
Methods and Materials: 100 women with abnormal screening mammograms,187 findings, and definite imaging or histopathological diagnosis were included. The screening mammography interpretation consisted of direct comparison of the tomosynthesis (DBT) examination with full field digital mammography (FFDM) images. The study radiologists subjectively rated the equivalence of the image quality of both the DBT and the FFDM examinations with no use of additional mammography, magnification views or comparison mammography. The next step was categorising the findings in both FFDM and DBT separately according to BIRADS classification and the statistical analysis evaluated the p values of DBT and FFDM as well as their sensitivities.
Results :All findings categorised as BIRADS 3 according to mammography showed reduction in number,particularly for masses, when examined with tomosynthesis. The image quality of tomosynthesis was subjectively rated as equivalent (53.5%) or superior (43.3%) to digital mammography in 96.8% of the total of findings; the test was highly significant (p <0.001). For masses, tomosynthesis image quality was rated as equivalent in 40.5% or superior in 58.1% of findings. Masses were 53 % of findings in which tomosynthesis had superior image quality. The FFDM Sensitivity was of 91.9 % compared with 95.2% for DBT.
Conclusion: The diagnostic potential of digital breast tomosynthesis is superior to that of full-field digital mammography by evaluating their image quality and their sensitivity. Based on a subjective analysis, DBT showed a significantly higher image quality compared with digital mammography in all finding types, especially in the characterisation of masses.

Ultrasound study of the pancreas with CPS (CEUS) and ARFI (elastography): improving the diagnosis of pancreatic tumours

M. D’Onofrio | Friday, March 8, 12:30 – 13:30 / Room L/M

Image fusion enables us to perform a direct, on-screen correlation between a current ultrasound study and a previously performed CT or MRI exam. Using this ability, the spatial resolution of the ultrasound image can be added to the superior overview of a CT or MRI providing additional clinical confidence, lesions first noted on CT or MRI may be more easily detected and characterised on ultrasound and interventions such as biopsies and tumour ablations may be guided by a combination of modalities. Participants in this symposium will become familiar with how image fusion adds another dimension both to diagnostic and interventional ultrasound.

B-0948 Computed tomography of the bowel: a prospective comparison study between four techniques

M. Revelli, F. Paparo, L. Bacigalupo, A. Garlaschi, L. Cevasco, E. Biscaldi, G. Rollandi | Monday, March 11, 14:00 – 15:30 / Room E2

Purpose: Our purposes were to compare the grade of bowel distension obtained with four different CT techniques dedicated for examination of small intestine (CT-enteroclysis and CT-enterography), colon (CT with water enema), or both (CT-enterography with water enema) and to assess patient tolerance towards each protocol.
Methods and Materials: We recruited four groups of 30 patients. Each group corresponded to a specific CT technique, for a total of 120 consecutive patients (65 male, 55 female; mean age 51.09±13.36 years). CT studies were evaluated in consensus by two gastrointestinal-dedicated radiologists who performed quantitative and qualitative analysis of bowel distension. Presence and type of adverse effects were recorded.
Results: CT-enteroclysis provided the best distension of jejunal loops (median diameter 27mm; range 17-32mm) compared with all other techniques (p<0.0001). Frequency of patients with an adequate distension of the terminal ileum was not significantly different among the four groups (p=0.0608). At both quantitative and qualitative analysis CT with water enema and CT-enterography with water enema determined a greater and more consistent luminal filling of the large intestine compared with the one provided by both CT-enteroclysis and CT-enterography (p<0.0001 for all colonic segments). Adverse effects were more frequent in patients from the CT-enteroclysis group (p<0.0028).
Conclusion: CT-enteroclysis allows an optimal distension of jejunal loops, but it is the most uncomfortable CT protocol. When performing CT with water enema, an adequate retrograde distension of the terminal ileum was provided in a high percentage of patients. CT-enterography with water enema provides a simultaneous optimal distension of both small and large bowel.

B-0576 Imaging features of acinar cell cystadenoma: can we differentiate them from branch duct IPMNs?

C. Delavaud, G. D’Assignies, J. Cros, P. Ruszniewski, P. Hammel, A. Couvelard, V. Vilgrain, M.-P. Vullierme

Purpose: Acinar cystic cystadenoma (ACC) of the pancreas is a rare benign entity first described in 2002, defined by histological criteria. Radiographic appearance had almost not been described so far. Most of the patients underwent surgical resection under the preoperative diagnosis of intraductal papillary mucinous neoplasms. The aims of this study are to define imaging diagnostic criteria of ACC based on radiopathological confrontation and to compare clinical, biological and imaging data between patients with ACC and with branch ducts IPMN.
Methods and Materials: All patients with ACC who underwent pancreatic surgery for suspicion of IPMN and the 20 last patients with histologically proven branch ducts IPMN were retrospectively included. Clinical and biological information were collected from the medical reports. Radiological and histological documents were reviewed in order to define imaging diagnostic criteria of ACC. Data were compared using the Chi-square test or Fisher’s exact test.
Results: ACC was symptomatic in all but one patient. There were no statistical difference between ACC and IPMN group with regard to clinical and biological data. Combination of four radiological criteria allowed differentiating ACC from IPMN: cyst calcification, presence of more than 5 cysts, clustered peripheral small cyst, and absence of communication with main pancreatic duct. Sensibility and specificity were, respectively, 75 and 100 % with combination of at least three of these criteria.
Conclusion: ACC is a rare benign pancreatic tumour with specific imaging features despite some similarities with IPMN. Recognition of this entity may help us to propose the diagnosis and prevent extensive surgery.

B-0188 Dynamic contrast-enhanced MRI can assess vascularity within pseudarthrotic clefts and predicts good clinical outcome

M.-A. Weber, K. Bloess, I. Burkholder, D. Bender, G. Schmidmaier, H.-U. Kauczor, O. Schoierer | Thursday, March 7, 14:00 – 15:30 / Room E1

Purpose: To prospectively evaluate whether dynamic contrast-enhanced (DCE) MRI can assess vascularity within pseudarthrotic clefts and predicts clinical outcome better than the clinical non-union scoring system (NUSS).
Methods and Materials: Sixty-four patients (mean age, 49.3 years) with non-union of an extremity fracture in computed-tomography received 3-Tesla MRI including DCE (coronal T1-weighted fat-saturated VIBE, TR/TE=3.76/1.35ms, 17 measurements, 2 mm slice thickness) after 0.1mmol/kg body-weight of gadoterat. We assessed vascularity within the pseudarthrotic cleft using a region-of-interest analysis. Signal intensity curves were subdivided into those with more intense contrast-agent uptake in the pseudarthrotic cleft than in normal adjacent muscle tissue (vascularised non-union) and those with similar or less uptake. The pharmacokinetic parameters of the Tofts model (K_trans, K_ep, iAUC, V_e) were correlated to the clinical outcome at one-year follow-up (n=37).
Results: Despite inserted osteosynthesis material, DCE parameters could be evaluated in n=60 at first visit. Sensitivity/specificity of vascularised non-unions as indicator of good clinical outcome was 77.3%/46.7% compared to 95.5%/26.7% using NUSS. Logistic regression revealed non-significant impact of NUSS on clinical outcome (p=0.27, odds ratio=0.97). At first examination, median iAUC (initial area under the enhancement curve) was 24.13 in patients with good outcome compared with 10.96 in non-responders (p=0.032), while K_trans, K_ep, and V_e were not significantly different. Using a receiver operating characteristic analysis, sensitivity/specificity of iAUC at the optimal cut-off value of 17.5 to predict outcome was 68.2%/76.9%. All pharmacokinetic parameters did not change significantly at the one-year control (n=18).
Conclusion: DCE MRI can assess vascularity in pseudarthrotic clefts. A vascularised non-union indicates good clinical outcome.

B-0406 Increased regional grey matter volume in Parkinson’s disease patients with excessive daytime sleepiness: an MRI study

L.C. Tzarouchi, M. Chondrogiorgi, A. Zikou, P. Kosta, M.I. Argyropoulou, S. Konitsiotis | Friday, March 8, 14:00 – 15:30 / Room B

Purpose: Excessive daytime sleepiness (EDS) is an important non-motor symptom of Parkinson’s disease (PD). The underlying neuropathological mechanism accounting for EDS is not well understood. The purpose of the present study was to determine regional grey matter (GM) volume changes in PD patients with EDS.
Methods and Materials: Seventeen PD patients with EDS (Epworth Sleepiness Scale ESS ≥ 12) (EDS-PD), 17 age and disease duration-matched PD patients (Epworth Sleepiness Scale ESS ≤ 6) and 17 age-matched healthy controls were enrolled in the study. The χ² and Student’s t tests were used to test for differences in demographic and clinical characteristics between groups. Differences in GM volume between groups were evaluated by applying the voxel-based morphometry (VBM) method.
Results: Total calculated levodopa equivalent dose was higher in EDS-PD when compared to PD patients (p<0.05). Comparison of EDS-PD with PD patients and controls showed increased GM volume bilaterally in the hippocampus, the parahippocampal gyrus, the fusiform gyrus and in cortical areas in the temporal, frontal and parietal lobes (p<0.001).
Conclusion: EDS-PD patients present increased regional GM volume in the mesolimbic/mesocortical dopamine pathway, which is activated during sleep. Drug-induced GM volume increase through a process of neuronal plasticity may represent the underlying mechanism.

A-224 C. Metabolic disorders

J.F. Schneider | Saturday, March 9, 08:30 – 10:00 / Room E2

Metabolic disorders may present at any age. Their clinical symptoms are often scarce or non-specific. Brain MRI is often used in the setting of an acute illness but may be delayed in slowly progressive disease. Imaging appearance can be confusing as acute and chronic signal intensity alterations may overlap in many disorders. Furthermore, imaging appearance will vary during the course of the disease. Recognition of signal changes in specific structures is most helpful in the acute setting before chronic changes set in, which will blur characteristic patterns. A systematic approach based on the pattern of brain involvement is useful in the analysis of neurometabolic disorders, and has even been computerized. First, a decision whether grey or white matter involvement or both must be made based upon volume and signal alterations on T1-wi, T2-wi, FLAIR imaging and contrast enhancement. Second, alterations within either focal grey matter structures or specific white matter tracts must be recorded and estimation upon their timing, whether acute or chronic, must be made. Finally, this pattern recognition must be supplemented by microstructural data from diffusion-weighted images (DWI) and metabolic data from proton MR spectroscopy (MRS). Additional information from DWI is often restricted to the acute setting, because chronic diffusivity changes are mainly driven by unspecific myelin breakdown. On the other hand, MRS may not only identify abnormal levels of normal metabolites or demonstrate the presence of abnormal metabolites, but can also be used to monitor therapy.