Iris Nöbauer-Huhmann

Medical University of Vienna, Wien, Vienna, Austria

Are you Iris Nöbauer-Huhmann?

Claim your profile

Publications (60)134.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To test the feasibility and accuracy of MR-guided soft tissue tumour biopsy at 3T, using the dynamic contrast-enhanced (DCE) information from staging MRI for intralesional targeting. After obtaining written informed consent for this institutional review board-approved study, 53 patients with suspected soft tissue tumours prospectively underwent preoperative staging MRI at 3T, including DCE, and subsequent MR-guided core needle biopsy. In 44/53 cases, DCE was heterogeneous and was used for intralesional biopsy targeting. Surgical, whole-specimen histology was used as the gold standard in 43/44 patients and revealed 42 soft tissue tumours (24 men; 18 women; mean age, 52 years; range, 19 - 84). Final surgical histology revealed eight benign lesions, six tumours of intermediate dignity, and 28 malignancies. All malignancies had shown heterogeneous DCE. The diagnostic yield of the biopsies was 100 % (42/42). Histological accuracy rates of biopsy were 100 % in predicting the dignity (42/42; 95 % CI [0.916 - 1.000]), 95.2 % for the tissue-specific entity (40/42; 95 % CI [0.847 - 0.987]), and 90.5 % for the tumour grade (38/42; 95 % CI [0.779 - 0.962]). Our preliminary study indicates that biopsy of soft tissue tumours can be performed accurately and safely with DCE targeted MR-guidance at 3T, using a combined staging/biopsy MRI protocol. • MR-guided soft tissue tumour biopsy using DCE for intralesional targeting is feasible. • Targeting by staging-MRI allows reliable planning of the biopsy approach. • The method seems accurate and safe as a combined staging/biopsy procedure in outpatients. • DCE-targeted biopsy seems useful in challenging large and heterogeneous tumours.
    European Radiology 01/2015; DOI:10.1007/s00330-014-3576-0 · 4.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This study evaluated the feasibility of computed magnetic resonance imaging (MRI) volumetry in conventional osteosarcomas. Secondly, we investigated whether computed volumetry provides new prognostic indicators for histological response of osteosarcomas after neoadjuvant chemotherapy. In a retrospective cohort study, data from the Vienna Bone Tumour Registry was used. MR images from 14 patients (male:female = 1.8, mean age 19 years) were analysed prior to and after neoadjuvant chemotherapy according to current therapy regimens. Histological response to chemotherapy was graded according to the Salzer-Kuntschik classification. Computed volumetry was performed for the intraosseous part, as well as the soft-tissue component and the tumour as a whole. In a setting of appropriate radiological equipment, the method has been considered to be well implementable into clinical routine. The mean tumour volume prior to chemotherapy was 321 (±351) ml. In good responders (n = 6), overall tumour volume decreased by 47 % (p = 0.345), whereas poor responders (n = 8) showed a 19 % decrease (p = 0.128). Neoadjuvant multidrug therapy remarkably changed the tumour composition. This is seen in a decrease of the mean ratio of soft-tissue to intraosseous tumour volume from 8.67 in poor responders and 1.15 in good responders to 1.26 and 0.45 (p = 0.065), respectively. Interestingly, the bony compartment of good responders showed a volume increase during neoadjuvant chemotherapy (p = 0.073). However, we did not find prognostic markers for histological tumour response to pre-operative chemotherapy. Separated volumetry of tumour segments revealed interesting insights into therapy-induced growth patterns. If verified in a larger study population, these results should be taken into account when planning ablative surgery.
    International Orthopaedics 11/2014; 39(1). DOI:10.1007/s00264-014-2606-5 · 2.02 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: To compare the contrast agent effect of a full dose and half the dose of gadobenate dimeglumine in brain tumours at 7 Tesla (7T) MR versus 3 Tesla (3T).
    European Radiology 09/2014; DOI:10.1007/s00330-014-3351-2 · 4.34 Impact Factor
  • I-M Nöbauer-Huhmann
    [Show abstract] [Hide abstract]
    ABSTRACT: Only approximately 1% of soft tissue tumors are malignant. Potentially malignant lesions can be recognized by ultrasound and submitted for magnetic resonance imaging (MRI). Radiography can supply valuable additional information. The MRI examination is the imaging reference standard for soft tissue tumors and also serves as local staging modality. Lesions which are indeterminate in MRI, or in which therapy is dependent on histology results, should be biopsied. Referral to a reference center is recommended. The multitude of soft tissue tumor entities are classified according to the World Health Organization (WHO) system (latest version 2013). Some tumors show characteristic locations and MRI morphology. Sarcoma staging by imaging is influenced by the size and site in comparison to the surface fascia. International standards must be adhered to: decisive for the patient is in particular the care by an experienced interdisciplinary tumor team.
    Der Radiologe 08/2014; 54(8):803-18. DOI:10.1007/s00117-014-2699-2 · 0.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Multimodal treatment regimens for Ewing's sarcoma have led to survival rates approaching 70% of patients with no metastases at diagnosis. However, these treatments have long-term side effects. Low bone mineral density (BMD) and risk of fractures can occur owing in part to chemotherapy and limited mobility from local control of the primary tumor.
    Clinical Orthopaedics and Related Research 07/2014; 472(11). DOI:10.1007/s11999-014-3777-5 · 2.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: This diffusion tensor MR imaging (DTI) study aimed to clarify the relationship of peripheral nerves and soft tissue tumors (STT) in 3D to optimize subsequent treatment. Methods: 26 consecutive STT patients (histologically malignant n=10, intermediate n=3, and benign n=13) underwent 3 Tesla MRI using an echoplanar DTI sequence. Deterministic tractography was performed. Fractional Anisotropy (FA) values were measured within peritumoral and distant ROIs. Results: Tractography depicted the 3D course of the sciatic (n=12), femoral (n=2), tibial (n=7), fibular (n=2), median (n=1), musculocutaneous (n=1), and ulnar (n=1) nerves in a regular (n=8/18, 44.4%) or thinned (n=7/18, 38.9%) fashion. The lowest peritumoral FA values, abrupt thinning, and/or complete discontinuity of trajectories were found in 2 cases with histologically proven tumoral nerve infiltration. Discussion: DTI clarifies the 3D topography between major peripheral nerves and STT and may be helpful in the assessment of peripheral nerve infiltration by malignant tumors. © 2014 Wiley Periodicals, Inc.
    Muscle & Nerve 06/2014; DOI:10.1002/mus.24313 · 2.31 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To test the dynamic contrast enhanced (DCE) sequence of soft tissue tumor staging MR for intralesional targeting with subsequent minimally MR-guided biopsy at 3T, and to compare DCE “hotspots” with diffusion-weighted imaging (DWI) and multivoxel 1H-MR spectroscopy (1H-MRS). METHOD AND MATERIALS Fifty-six patients with suspected soft tissue tumors prospectively underwent preoperative staging MR with subsequent MR-guided core needle biopsy at 3T after written informed consent, according to Institutional review board approval. Surgical histology available in 54 patients revealed 53 soft tissue tumors (29m, 24f, mean age 54 years, range 19-90). DCE was conducted in 50/53 patients (contrast agents: Gd-BOPTA, Gd-DOTA, and Gd-DO3A-butrol), DWI-MSh FH in 51/53 patients, and 1H-MRS in 37/53 patients. Matching of the most suspicious regions in DWI and 1H-MRS with DCE results was assessed. RESULTS DCE was heterogeneous in 42 cases, including all malignant tumors. In 2 cases, DWI was additionally used for targeting. In 6 cases appearing homogeneous on all sequences, biopsy was taken arbitrarily. 3 small lesions required no region selection. Diagnostic yield was 98.1% (52/53). The accuracy rates of biopsy were 100% (52/52) in predicting the dignity, 96.2% for definitive tissue diagnosis, and 92.3% for tumor grade. DCE matched with preselected DWI regions in 87.5%, and with 1H-MRS in all assessable regions. The diffusion weighted sequence was of limited value for the selection of the biopsy area. Spectroscopy could be compared with the DCE target region in 23/37 patients only. Area match of 1H-MRS with the hotspots revealed by DCE was observed in all assessable cases, but, due to technical restraints, tumor coverage was not possible by 1H-MRS in feasible examination time. CONCLUSION Our preliminary study indicates, that biopsy of soft tissue tumors can be performed accurately and safely by DCE targeted MR-guidance at 3T, using the DCE staging sequence in combined staging/biopsy MRI in outpatients. DWI was of limited value. 1H-MRS results were promising, but the method cannot be recommended for biopsy targeting in its present form. CLINICAL RELEVANCE/APPLICATION In soft tissue tumors, the DCE-sequence of staging MR can be used accurately and safely for targeting of minimally-invasive MR-guided biopsy, which might be useful especially in heterogeneous tumors.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • Iris-Melanie Nöbauer-Huhmann
    Wiener klinische Wochenschrift 11/2013; 125. DOI:10.1007/s00508-013-0465-5 · 0.79 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective To quantitatively evaluate the position, size, and shape of the menisci in subjects with radiographic knee osteoarthritis (OA) compared to subjects without OA, using magnetic resonance imaging (MRI). Methods We studied the right knees of 39 Osteoarthritis Initiative participants (24 women and 15 men with a mean age of 59.6 +/- 8.7 years) with medial compartment radiographic tibiofemoral OA (Kellgren/Lawrence grade of 2 or 3). Subjects were matched individually for age, sex, and height to controls without knee OA and without risk factors for knee OA. The right knees of the controls were used as references. One observer performed manual segmentation of the tibial plateau and the medial and lateral meniscus based on a coronally reconstructed double-echo steady-state sequence with water excitation, focusing on 5 central 3T MRIs. ResultsIn OA knees, there was less meniscal coverage of the medial tibial plateau (435 mm(2) versus 515 mm(2); P = 0.0004), the medial meniscus body showed more extrusion (2.64 mm versus 0.53 mm; P < 0.0001), and the peripheral margin had a more convex shape, i.e., bulged more (mean 0.61 mm versus 0.27 mm; P < 0.0001). The thickness or volume of the medial meniscus body of OA knees did not differ substantially from reference knees. In contrast, in OA knees the lateral meniscus body had a larger volume (mean 266 mm(3) versus 224 mm(3); P = 0.0005) and extruded more (mean 1.16 mm versus -1.01 mm; P < 0.0001), and the external margin bulged more (mean 0.53 mm versus 0.35 mm; P < 0.0001), than in reference knees. Conclusion Our findings indicate altered meniscal position and shape (i.e., more bulging) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences.
    Arthritis & Rheumatology 07/2013; 65(7). DOI:10.1002/art.37947 · 7.87 Impact Factor
  • Source
    Dataset: IR37-114
  • Source
    Osteoarthritis and Cartilage 09/2012; 20(9):1056. DOI:10.1016/j.joca.2012.06.014 · 4.66 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: To compare sodium imaging of lumbar intervertebral disks in asymptomatic volunteers at 7-T magnetic resonance (MR) imaging with quantitative T2 mapping and morphologic scoring at 3 T. Materials and Methods: Following ethical board approval and informed consent, the L2-3 to L5-S1 disks were examined in 10 asymptomatic volunteers (nine men, one woman; mean age, 30 years; range, 23-43 years). At 7 T, normalized sodium signal-to-noise ratios were calculated, by using region-of-interest analysis. At 3 T, T2 mapping was performed with a multiecho spin-echo sequence (repetition time msec/echo times msec, 1500/24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144, 156). T2 values were calculated over the nucleus, with a pixelwise, monoexponential nonnegative least-squares-fit analysis. Morphologic grading according to a modified Pfirrmann score was assessed independently by three experienced musculoskeletal radiologists, and Pearson correlation analysis of the covariates was performed. Results: The mean normalized sodium signal intensity was 275.5 ± 115.4 (standard deviation). The T2 mapping showed a mean value of 89.8 msec ± 19.34. The median modified Pfirrmann score was 2b (90% had score ≤ 3c). The Pearson correlation coefficient showed a cubic function between sodium imaging and the modified Pfirrmann score, a moderate inverse correlation between T2 mapping and the modified Pfirrmann score (r = -0.62), and no correlation between sodium imaging and T2 mapping (r = 0.06). Conclusion: The results suggest that MR imaging of the intervertebral disk, using sodium imaging and T2 mapping, can help characterize different component changes and that both of these methods are to some degree related to the Pfirrmann score. © RSNA, 2012.
    Radiology 08/2012; 265(2):555-64. DOI:10.1148/radiol.12111920 · 6.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Introduction: In chronic Achilles tendinopathy, biochemical alterations precede macroscopic changes. Tendinopathy is usually accompanied by disaggregation of the microfibrillar bundles due to the greater quantities of water and PG, mainly, chondroitin sulphate A. An almost doubling of glycosaminoglycans (GAG) was observed in pathologic tendons [1,2]. By analogy with cartilage, sodium content should be higher in regions with GAG increase due to counter-ion mechanism between Na+ and negatively charged GAG chains [3]. The purpose of this study was to investigate the feasibility of sodium MR imaging in the diagnosis of Achilles tendinopathy Methods and Materials: Twenty healthy volunteers with no history of pain in the Achilles tendon (AT) (six males, fourteen females, mean age 38 ± 11 years) and eight patients (four males, years; four females, mean age 34 ± 11 years) with clinical findings of chronic Achilles tendinopathy were included in the study. Moreover, five fresh human cadaver lower legs from four different subjects (two males and two females, mean age, 51±13 years) were used. To acquire a sodium signal from the AT, a 3D-GRE (gradient echo) sequence optimized for sodium imaging was used. The length of the excitation pulse was set to 970 μs to avoid exceeding the specific absorption rate limit. The images were reconstructed in sagittal plane. The parameters of the 3D-GRE sodium sequence were set as follows: TE = 8.34ms; TR = 17ms; FOV = 199 × 199; slice thickness 3mm; flip angle 50°; 12 averages; and acquisition matrix 224 × 224 pixels. The total measurement time for sodium imaging, including flip angle calibration and localizers, was about 32 minutes. To calculate the signal-to-noise ratio (SNR) of each region of the AT, the mean sodium signal was divided by the standard deviation of noise, calculated from the same ROI on the "pure" noise images. To perform a biochemical analysis, samples from cadaver AT were taken from the MTJ (musculo-tendon junction), MID (mid region), and INS (insertion area) region according to segmentation of the tendon on MR images. Results are reported as micrograms of GAG per milligram of sample dry weight. A binary classification test was performed on the data to obtain the specificity and sensitivity of the method. Results: The median of sodium SNR in fifteen samples from the cadaver ATs was 9.6 (interquartile range [IQR]: 7.9-12.6). The median of GAG content assessed biochemically in fifteen samples from cadaver ATs was 1.7 (IQR: 1.3-2.7). The Pearson correlation coefficient between sodium SNR and GAG content was r = 0.7135 (N = 15). Mean bulk sodium SNR was 4.9 ± 2.1 in healthy controls and 9.3 ± 2.3 in patients with Achilles tendinopathy. The difference between the means was statistically significant (p < 0.05). When looking at the SNR changes regionally, the differences in SNR were also statistically significant in the INS and MID regions. The SNR in the MTJ was almost doubled in patients compared to healthy controls, in absolute value; (p < 0.05). At the sodium SNR equal to 7.5 (a threshold determined by ROC curve), the specificity of the method was 88.24%, and the sensitivity was 85.71%. Conclusion: This work demonstrated the feasibility of sodium MRI to detect differences in the sodium signal between healthy tendons and patients with Achilles tendinopathy in in vivo conditions. The correlation with the different GAG concentrations within the AT to sodium signal was shown in cadaver tendons. Notably, we observed several cases where a focal abnormality of the tendon shape was not associated with an abnormal signal increase on standard MR, but with abnormal values in all three parts of the tendon on sodium images. This may imply a higher sensitivity of sodium imaging for the detection of earlier stages of Achilles tendinopathy, and may provide a sensitive tool for the follow-up of patients after different therapies for the Achilles tendon. However, it is important to note that the correlation between GAG content and sodium signal measured in cadaver ankles should be viewed with caution, since post-mortem processes might cause the changes in biochemical composition of the tendon tissue. References: [1] Fu SC et al, Clin J Sport Med. 2007;17(2):129-34 [2] Chard MD, Annals of the rheumatic diseases. 1994;53(1):30-4. [3] Tratnig S., et al., Radiology. 2010;257(1):175-84 Fig. 1. Example images of 28y old healthy volunteer; the arrows point to centers of regions used for evaluation. (the scale represents signal intensity)
    ISMRM 2012; 05/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND AND PURPOSE:Patients with cervical spine syndrome often experience pain during the MR examination. Our aim was to compare the quality of cervical spine MR images obtained by parallel imaging with those of nonaccelerated images, with the goal of shortening the examination time while preserving adequate image quality.MATERIALS AND METHODS:A phantom study and examinations of 10 volunteers and 26 patients were conducted on a clinical 3T scanner. Acquisitions included axial T2WI, sagittal T2WI, T1WI, and T2TIRM sequences. Nonaccelerated sequences and accelerated sequences with different numbers of averages and different accelerations, with a scanning time reduction of 67%, were performed. For quantitative analysis, the SNR was obtained from the phantom measurements, and the NU was calculated from the volunteer measurements. For qualitative analysis, 3 independent readers assessed the delineation of anatomic structures in volunteers and the visibility of degenerative disease in patients.RESULTS:In the phantom study, as expected, the SNR of the nonaccelerated images was higher than the SNR of the same sequence with parallel imaging. In vivo, the NU was higher when applying fewer averages or parallel imaging, compared with the nonaccelerated images. The analysis of the subjective parameters in the volunteers and patients showed that a scanning time of 48% of the original protocol could be obtained by combining the following sequences: sagittal T1WI with 1 average; sagittal T2WI with acceleration factor 3; sagittal T2TIRM with acceleration factor 2; and axial T2* GRE with acceleration factor 2.CONCLUSIONS:Parallel imaging of the cervical spine at 3T allows shortening of the examination time by 52%, preserving adequate image quality.
    American Journal of Neuroradiology 05/2012; 33(10). DOI:10.3174/ajnr.A3101 · 3.68 Impact Factor
  • P. Lang, H. Yoshioka, D. Steines, I.-M. Nöbauer-Huhmann, H. Imhof
    [Show abstract] [Hide abstract]
    ABSTRACT: Die MRT ist die beste verfügbare Untersuchungsmethode zur Darstellung des normalen und geschädigten Gelenkknorpels. Sie gibt nicht nur Aufschluss über die Morphologie des geschädigten Areals, sondern auch über die biochemische Zusammensetzung des Gelenkknorpels. Neue Bildverarbeitungstechniken wie die dreidimensionale Erfassung/Darstellung der Knorpeldicke werden bei der Entwicklung einer automatisierten Analyse des Knorpelverlustes helfen. Diese Techniken sind auch ideal zur Verlaufsbeobachtung von Patienten, die sich einer Behandlung mit knorpelregenerierenden Substanzen unterziehen. MRI is the most accurate noninvasive technique available for assessment of normal articular cartilage and cartilage lesions. MRI cannot only provide morphologic information about the area of damage, but can also provide unique insight into the biochemical composition of the articular cartilage. New image processing techniques such as three-dimensional mapping of cartilage thickness will help to establish automated analysis of cartilage loss. Theses techniques are ideally suited for monitoring patients who undergo treatment with new chondroregenerative drugs.
    Der Radiologe 04/2012; 40(12):1141-1148. DOI:10.1007/s001170050898 · 0.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Due to the small size and complexity of its constituents, the triangular fibrocartilage complex (TFCC) has been a challenging structure for magnetic resonance (MR) imaging. Higher-field MR units, at 3T and 7T, with increased spatial resolution and the development of novel MR sequences, are promising tools for an improved visualization of the ulnocarpal complex. Anatomically, the TFCC consists of the TFC proper, the ulnomeniscal homolog, the ulnar collateral ligament, the ulnotriquetral and ulnolunate ligament, and radioulnar ligaments at the volar (palmar) and the dorsal side, as well as the sheath of the extensor carpi ulnaris tendon and the capsule of the distal radioulnar joint. This article describes the normal anatomy of the TFCC and its appearance on high-field MRI. Anatomical variants, such as the positive ulnar variance, and changes during pronation and supination are addressed.
    Seminars in Musculoskeletal Radiology 04/2012; 16(2):93-103. DOI:10.1055/s-0032-1311761 · 0.95 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The objective was to compare patients after matrix-associated autologous chondrocyte transplantation (MACT) and microfracture therapy (MFX) of the talus using diffusion-weighted imaging (DWI), with morphological and clinical scoring. Twenty patients treated with MACT or MFX (10 per group) were examined using 3 T magnetic resonance imaging (MRI) at 48 ± 21.5 and 59.6 ± 23 months after surgery, respectively. For comparability, patients from each group were matched by age, body mass index, and follow-up. American Orthopaedic Foot and Ankle Society (AOFAS) score served as clinical assessment tool pre- and postoperatively. DWI was obtained using a partially balanced, steady-state gradient echo pulse sequence, as well as the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score, based on a 2D proton density-weighted turbo spin-echo sequence and a 3D isotropic true fast imaging with steady-state precession sequence. Semi-quantitative diffusion quotients were calculated after region of interest analysis of repair tissue (RT) and healthy control cartilage, and compared among both groups. The mean AOFAS score improved significantly (P = 0.001) for both groups (MACT: 48.8 ± 20.4-83.6 ± 9.7; MFX: 44.3 ± 16.5-77.6 ± 13.2). No differences in the AOFAS (P = 0.327) and MOCART (P = 0.720) score were observed between MACT and MFX postoperatively. DWI distinguished between healthy cartilage and cartilage RT in the MFX group (P = 0.016), but not after MACT treatment (P = 0.105). Significant correlations were found between MOCART score and DWI index after MFX (Pearson: -0.648; P = 0.043), and between the diffusivity and longer follow-up interval in MACT group (Pearson: -0.647, P = 0.043). Whereas conventional scores reveal a similar outcome after MACT or MFX treatment in the ankle joint, DWI was able to distinguish between different RT qualities, as reported histologically for these diverse surgical procedures.
    Osteoarthritis and Cartilage 03/2012; 20(7):703-11. DOI:10.1016/j.joca.2012.03.008 · 4.66 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: Recently, the development of ultra-high field MR scanners is growing rapidly. In theory, if the coil and the subject are equivalent then the SNR will be almost linearly related to B 0 . SNR behavior, however, is apparently more complex, especially for human applications at 7T (mostly due to susceptibility artifacts and widened chemical shift) [1]. The aim of this study was to investigate the performance of clinical MR sequences in in-vivo ankle imaging at ultrahigh-field (7T). Ultrahigh-field MR imaging may substantially benefit from higher signal-to-noise ratio (SNR) and better spatial resolution. Methods and Materials: Ten volunteers were consecutively measured at 3T MRI (Tim Trio, Siemens Healthcare, Erlangen, Germany) and 7T (Siemens Healthcare, Erlangen, Germany) with similar multi-element coils (3T -> 8-channel knee coil, In Vivo, OR, USA, 7T -> 28 channel knee coil, QED, USA) on each scanner with three different standard clinical sequences: 1). 3D-GRE, sagittal orientation, T 1 weighted, TE 3.57ms, TR 8.3ms and spatial resolution [0.4mm] 3 , 2) 2D-FSE, coronal orientation, PD-weighted, TE 25ms, TR 3000ms and spatial resolution [0.31x0.31x3.00mm] 3) and 3) 2D SE, T 1 weighted, TE 13ms, TR 800ms and resolution [0.36x0.36x3.00 mm] 3). SNR of different structures (cartilage, bone, synovial fluid, Kager's fatpad, muscle and Achilles tendon, Fig. 1) was compared between 3T and 7T using one-way ANOVA test for repeated measures. Standard deviation of noise was estimated by Steckner 'difference pixels' method [2]. Contrast-to-noise ratios (CNR) were compared using the same statistical approach between these structures: cartilage/bone, cartilage/fluid, cartilage/muscle and muscle/fat pad. Results: Overall mean SNR for 3T was 24.74 ± 5.16 and for 7T 53.25 ± 14.8 (Fig 2, 3). SNR was significantly higher at 7T vs 3T in the following structures (# sequences): bone (1,2), cartilage (1,2,3), fluid (1,2,3), fat pad (1,2,3), muscle (1,2,3) and tendon (1,2). Non-significant differences were found only with sequence #3 in bone (p=0.207), fat pad (p=0.51) and tendon (p=0.401). We observed higher CNR at 7T as a ratio of selected tissues (sequences): cartilage/bone(1,2), cartilage/fluid (2), cartilage/muscle (2) and muscle/fat pad (1,2). Fig. 1 Definition of region-of-interests on 3T image (similarly done on 7T) drawn in JiveX (Visus, Bochum, Germany).
    ISMRM 2011; 05/2011
  • Bone 05/2011; 48. DOI:10.1016/j.bone.2011.03.611 · 4.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this article, the authors propose a new gold standard data set for the validation of two-dimensional/three-dimensional (2D/3D) and 3D/3D image registration algorithms. A gold standard data set was produced using a fresh cadaver pig head with attached fiducial markers. The authors used several imaging modalities common in diagnostic imaging or radiotherapy, which include 64-slice computed tomography (CT), magnetic resonance imaging using T1, T2, and proton density sequences, and cone beam CT imaging data. Radiographic data were acquired using kilovoltage and megavoltage imaging techniques. The image information reflects both anatomy and reliable fiducial marker information and improves over existing data sets by the level of anatomical detail, image data quality, and soft-tissue content. The markers on the 3D and 2D image data were segmented using ANALYZE 10.0 (AnalyzeDirect, Inc., Kansas City, KN) and an in-house software. The projection distance errors and the expected target registration errors over all the image data sets were found to be less than 2.71 and 1.88 mm, respectively. The gold standard data set, obtained with state-of-the-art imaging technology, has the potential to improve the validation of 2D/3D and 3D/3D registration algorithms for image guided therapy.
    Medical Physics 03/2011; 38(3):1481-90. DOI:10.1118/1.3553402 · 3.01 Impact Factor

Publication Stats

804 Citations
134.17 Total Impact Points

Institutions

  • 2006–2014
    • Medical University of Vienna
      • • Department of Biomedical Imaging and Image-guided Therapy
      • • Department of Radiology
      • • Klinische Abteilung für Rheumatologie
      Wien, Vienna, Austria
  • 2002–2012
    • University of Vienna
      • • Division of Gastroenterology and Hepatology
      • • Universitätsklinik für Radiodiagnostik
      Vienna, Vienna, Austria
  • 2011
    • Christian-Albrechts-Universität zu Kiel
      • Institute of Food Economics and Consumption Studies
      Kiel, Schleswig-Holstein, Germany
  • 2003–2004
    • Vienna General Hospital
      Wien, Vienna, Austria