B-0158 Initial clinical results of simultaneous PET/MRI in comparison with PET/CT in patients with head and neck cancer
P. Stumpp, K. Kubiessa, S. Purz, M. Gawlitza, A. Kühn, K.G. Steinhoff, A. Boehm, R. Kluge, T. Kahn | Thursday, March 7, 14:00 – 15:30 / Room C
Purpose: Describing diagnostic capability of simultaneous PET/MRI in comparison with PET/CT and their single components CT, MRI and PET in an initial prospective study based on 17 patients with head-and-neck cancer.
Methods and Materials: 17 patients with head-and-neck cancer received an 18F-FDG-PET/CT for staging or follow-up and an additional simultaneous PET/MRI scan with a whole body imaging part and a dedicated examination of the neck. Sole MRI, CT and PET components of the multimodal acquisitions plus the PET/MRI and PET/CT examinations were evaluated independently, blinded and in a randomised order by two readers. Results were compared with the reference standard, and sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were calculated.
Results: 23 malignant tumours and 55 benign changes were found with the reference standard. For PET/CT the two reader groups showed a sensitivity of 78.3% and 87 %, a specificity of 85.5% and 89.1%, a PPV of 71.4% and 75 % and a NPV of 90.7% and 94 %. For PET/MRI sensitivity was 78.3% and 82.6%, specificity 81.8% and 94.5%, PPV 65.5% and 85.7% and NPV 91.2% and 93.8%. Evaluation of the single PET part from PET/CT revealed highest sensitivity of 95.7%, whereas evaluation of the sole MRI component from PET/MRI showed best specificity of 96.4%. There was a high interrater agreement in all modalities (Cohen’s kappa coefficient: 0.61 – 0.82).
Conclusion: PET/MRI of patients with head and neck cancer yielded good diagnostic capability, similar to PET/CT. Further studies on larger cohorts to prove these first results seem justified.
B-0012 Language impairment and reduced structural connectivity in Rolandic epilepsy
R. Besseling, J. Jansen, W.H. Backes | Thursday, March 7, 10:30 – 12:00 / Room C
Purpose: Rolandic epilepsy (RE) is a childhood epilepsy with mild seizure semiology and epileptic discharges originating from the sensorimotor (Rolandic) area. A serious co-morbidity in RE is language impairment, for which we aim to find a correlate using structural connectivity.
Methods and Materials: Diffusion MRI was performed at 3.0 Tesla and 2×2×2 mm voxel size with b=1200 s/mm2 and 66 diffusion gradient directions in 23 children with RE with proven language deficits and 23 matched controls. Constrained spherical deconvolution provided voxel-wise tract orientations and whole-brain tractography (5M streamlines). For each of the 4 Rolandic areas (bilateral pre- and postcentral gyri), the streamlines to any of the 70 regions, obtained by automatic cortical parcellation (Freesurfer), were selected from the whole-brain tractogram. For reliable connections (top 20 % of number of streamlines), connectivity was quantified by tract fractional anisotropy (FA), compared between groups, and correlated to language scores.
Results: In the left hemisphere, reduced tract FA was found for connections between the Rolandic areas and inferior frontal gyrus (Broca’s area) and supramarginal gyrus (Wernicke’s area), but not for contralateral homologue regions. For the aberrant connection between the left postcentral and inferior frontal gyrus, tract FA decreased with languages score in the RE group (p=0.04).
Conclusion: In RE structural connectivity between Rolandic and language areas is disturbed and correlates with the language dysfunction. This provides a neuronal link between the location of the epileptic discharges and the language impairment. This research was supported by the Dutch Epilepsy Foundation.
A-117 Pitfalls in neck imaging
F.A. Pameijer | Friday, March 8, 10:30 – 12:00 / Room C
Pitfall: “a hidden or unexpected danger or difficulty”. Imaging methods can provide an extraordinary amount of useful data to specialists treating head and neck (cancer) patients. It is crucial that these data are used to full advantage of individual patients. The most important factor in this process is mutual cooperation between the physicians in charge of patient care and the diagnostic imaging specialist. Pitfalls in the head and neck may present in various ways: normal variants may look like disease, incidental findings are frequently encountered, suboptimal technique may obscure important findings. Moreover, many pitfalls are directly related to technical errors. In this potential ‘minefield’, the post-treatment patient presents a major challenge to the imaging specialist. Ablative surgery usually results in distortion of the anatomy, especially when combined with flap reconstruction. When adequate preoperative and/or baseline postoperative imaging is lacking, determination of recurrence on a single postoperative examination may well be impossible. PET CT (MR) and advanced MR-techniques; e.g. Diffusion Weighted Imaging (DWI) or Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) can be helpful in this setting. The presentation aims to familiarize general radiologists, who have an interest in head and neck imaging, with common pitfalls encountered on CT and MR studies focussing on the neck. Both the pre-therapeutic, as well as the post-treatment setting, will be discussed using examples from daily practice.
B-0786 Evaluation of a new method for the assessment of anterior acetabular coverage and hip joint space narrowing
R. Ferré, E. Gibon, A. Feydy, H. Guerini, R. Campana, N. Zee, C. Bourdet, M. Hammadouche, J.-l. Drapé | Monday, March 11, 10:30 – 12:00 / Room E1
Purpose: The Lequesne’s false profile (LFP) view is commonly used to evaluate hip joint space narrowing (JSN) and anterior acetabular coverage using the vertical-center-anterior margin (VCA) angle. A novel low-dose biplanar slot scanner (SS) allows simultaneous acquisitions of weight-bearing oblique views of both hip joints. The aim was to compare LFP views versus biplanar oblique views obtained by SS.
Methods and Materials: LFP views were obtained on 56 hips on a computed radiography system. On the same hips, simultaneous oblique views of both hips were acquired in the SS, with the patient’s pelvis positioned at 45° from each acquisition plane. Two independent observers measured VCA angle and JSN on each acquisition. JSN was evaluated through the joint space/femoral head diameter ratio. Measurements from both techniques were compared using the student t-test and the Pearson’s correlation coefficient. Interobserver agreement of VCA angle and JSN assessments were calculated with the intraclass correlation coefficient (ICC).
Results: VCA angle was 33.5° (SD = 6.2°) with SS and 35° (5.6°) with LFP views (p<0.05). Pearson correlation coefficient between two techniques was 0.78 (p<0.01). JSN was 0,114 (SD = 0.03°) with SS and 0.108 (SD = 0.03°) with LFP views (p<0.05). Pearson correlation coefficient was 0.85 (p<0.01). ICCs for VCA angle were 0.91 with SS and 0.69 with LFP views. ICCs for JSN evaluation were 0.76 for both SS and LFP views.
Conclusion: SS is a reliable, easy, and low-dose evaluation of JSN and VCA angle despite a slight angular positioning compared with LFP.
B-0625 Features on MRI after transanal endoscopic microsurgery in patients with rectal cancer
L.A. Heijnen, M. Maas, M.H. Martens, D.M.J. Lambregts, J.W.A. Leijtens, W. Deserno, G.L. Beets, R.G.H. Beets-Tan | Sunday, March 10, 10:30 – 12:00 / Room A
Purpose: Transanal endoscopic microsurgery (TEM) is a minimal invasive technique for local resection of T1 and selected T2 tumours and is also an emerging option for good-responders after chemoradiation. In most centres follow-up includes regular MRI. This study aimed to describe the MR morphology of the rectal wall during follow-up in patients that received TEM.
Methods and Materials: Forty-nine patients underwent a post-TEM MRI in our centre. For 21 patients only one post-operative MRI was available. For 28 patients >1 MRIs were available. The MR morphology of the TEM-site was studied on the consecutive MR examinations. 32 patients were primary treated with TEM, 17 patients underwent chemoradiation followed by TEM.
Results: We identified three morphological patterns: (1) rectal wall thickening with or without fibrosis, (2) a notch at the TEM-location, and (3) irregular delineation of the rectal wall. Multiple patterns could occur within one patient. 32 patients (65%) had rectal wall thickening, 17 patients (35%) a notch, and 28 patients (57%) irregular delineation of the rectal wall. In addition to these patterns, oedema (due to chemoradiation) persisted in post-chemoradiation TEM-patients. Ten patients had dehiscence after TEM post-chemoradiation (n=58%). Six luminal recurrences occurred; 3 had rectal wall thickening, 3 a notch, and 5 an irregular rectal wall.
Conclusion: Three patterns were identified on MRI after TEM. This enables radiologists to monitor this group of patients more accurately. Since minimal invasive techniques are gaining, it is very important for radiologists and surgeons to have knowledge about the normal follow-up findings after TEM.
A-534 Imaging of renal trauma
V. Logager | Monday, March 11, 08:30 – 10:00 / Room C
Approximately, 10 % of all trauma admissions have kidney injuries. According to the American Association of Surgeons in Trauma (AAST), blunt traumas can be graded in a 5-point Renal Injury Scale. (Moore EE, Shackford SR, Pacher HL et.al. Organ Injury Scaling: Spleen, Liver and Kidney. J. Trauma 1989;29:1664-1666). On the basis of the patient’s clinical findings an imaging algorithm is set. In general, patients that are normotensive with microscopic haematuria have less than 0.2% risk of serious kidney damage and imaging is unnecessary, whereas patients with either: A) gross haematuria or B) microscopic haematuria and blood pressure less than 90mmHg or occasionally C) microscopic haematuria and positive result of diagnostic peritoneal lavage will require imaging. Contrast-enhanced CT is the way to go. Imaging should be in 3 phases (cortico medullary, delayed 3-5 min and late phase (more than 10 min). Image reading should be a multiplanar approach. Most of the findings do not require surgical intervention, the rest does. On the basis of case presentations, findings will be analysed, discussed and correlated to the patient’s clinical status and treatment possibilities, including where and which signs to look for. Which modality could be used to solve the diagnostic problem when the clinical picture does not fit with the radiological picture. Always expect the unexpected.
A-511 fMRI in epilepsy
N. Bargalló | Sunday, March 10, 16:00 – 17:30 / Room G/H
Functional MRI (fMRI) is a non-invasive tool that is capable to detect the subtle homodynamic changes produced in regional brain activation. The main fMRI clinical application until now is localization and evaluation of brain eloquent areas in surgical planning of brain pathology. fMRI application in epilepsy patients are language lateralization, memory function assessment and localization of ictal and interictal BOLD changes. There are several factors that can influence the results of a fMRI experiment such as the scan noise for the rest condition, the simplicity of the task performance, the monitoring of the experiment during the exam, how to achieve a real baseline condition and the most important, to use the most specific paradigm that would activate the selected brain areas. In practical approach, one must be aware that sometime fMRI studies are applied in paediatric or impaired cognitive epilepsy population when deciding the language or memory paradigm, and is recommended to use multiple and feasibility tasks to assure the results. fMRI for language lateralization is currently used in the clinical practice and provides comparable results to the intracarotid amobarbital test (IAT). In fMRI studies for memory function assessment, results show changes in epileptic patients, but further studies are required to validate this technique to an individual level. A new application is ictal or interictal fMRI with EEG recorded that provide more detailed information about simultaneously electrographic and homodynamic changes in the seizure process, with encouraging results for epileptogenic area localization and propagation patterns.
A-245 Pre-therapeutic radiological evaluation
J. Raupach, O. Renc, P. Hoffmann, J. Zizka; | Saturday, March 9, 08:30 – 10:00 / Room N/O
Endovascular abdominal aortic aneurysm repair (EVAR) was introduced over 20 years ago to primarily treat old and sick patients. Due to technical improvements and satisfactory clinical results of this technology, the number of patients treated with stent-grafts is steadily increasing. There is also tendency to use this therapy for ruptured abdominal aortic aneurysms. Pre-operative assessment of aortic morphology regarding suitability for stent-graft implantation is, therefore, an important challenge for every radiologist now. Main limitation of EVAR is unfavourable anatomy of landing zones and access vessels. Gold standard for EVAR planning is contrast-enhanced CTA. Alternative modality for patients with contraindications for CT, such as renal impairment, is unenhanced MR with steady-state free precession sequence. A number of 2D or 3D reconstructions are generated to provide information about the aneurysm morphology. Dedicated vessel analysis and planning software can be applied. Usually, axial images and thin MPR reconstructions are sufficient in emergent cases. Proper stent selection is a domain of operator and is still matter of his/her experience. The planning procedure can be subdivided into 4 different sections: infrarenal neck, aneurysmal sac, aortic bifurcation and access vessels. There are several critical and rules which must be obeyed during the evaluation process and general radiologists should be aware of. The presentation will review main inclusion and exclusion criteria for EVAR.
A-028 Ultrasound elastography
A. Athanasiou | Thursday, March 7, 16:00 – 17:30 / Room F2
Breast ultrasound elastography provides information about tissue elasticity Young modulus E = s / e, where s is the compression (stress) and e is the deformation (strain) of the tissue. It is a complementary tool to breast ultrasonography, easily performed in clinical practice. Two elasticity modes are currently available: strain imaging, where manual compression is applied to the ultrasound probe and tissue displacement is registered; tissue deformation is then calculated by means of dedicated software providing real-time elasticity images (color- or grey-coded) superimposed on B-mode imaging. This is a qualitative or semi-quantitative mode. Shear wave imaging, where US probe is used to induce mechanical vibrations using acoustic radiation force generating local tissue displacement. This mode provides quantitative information about either tissue displacement velocity or tissue stiffness itself in kPa. Functional information provided by elasticity imaging can be particularly useful for BIRADS 3 or 4a lesions. Various studies indicate that elasticity combined to B-mode imaging can improve breast ultrasound specificity up to 75-88%. False negative findings may be encountered in case of “soft” lesions (mucinous, medullary or cystic carcinomas) or inflammatory cancers. Differentiation between echogenic cysts and homogeneous solid lesions (such as fibroadenomas) can be improved as cystic features are usually specific in elasticity imaging. Iso-echoic lesions such as infiltrating lobular carcinomas may be better delimitated. Lymph-node characterization and microcalcification assessment can be improved, although few data are available and need further validation. 3D elastography is actually in progress and would be useful in monitoring response to neoadjuvant treatment.
A-024 Finding the time and resources in the radiology department
J. del Cura | Thursday, March 7, 16:00 – 17:30 | Room F1
One of the problems of undergraduate teaching of Radiology is the lack of time for teaching, due to competition for resources with other academic disciplines. Available classroom time and hours of practice are often insufficient to teach the increasingly complex modern Radiology. Also, the availability of financial resources to hire staff or access to educational facilities is competitive and limited, especially in a context of economic crisis. A good solution is to shift the paradigm of education, changing theoretical teaching into self-learning by students. This change allows to free class time to effectively teach Radiology. Classes are converted in workshops, doubt-solving sessions and problem-based learning, all of which matches better with a visual discipline like Radiology. Both on-line classes and e-learning can be useful for this purpose. This kind of teaching also makes Radiology a very attractive discipline for Medicine students. Also, Radiology practices can be carried out using custom computer applications. The lack of professors (and time) for practices can be solved with the help of residents, who are willing to participate as they are more prone to understand the learning needs of the students. Finally, the lack of economic resources makes it is necessary to seek alliances: with the industry, professional associations or with professors from other universities, sharing resources. Internet also provides free materials that can be used to teach.