Publications by authors named "Christian Czerny"

46 Publications

Pembrolizumab plus docetaxel for the treatment of recurrent/metastatic head and neck cancer: A prospective phase I/II study.

Oral Oncol 2022 Jan 26;124:105634. Epub 2021 Nov 26.

Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, Vienna A-1090, Austria.

Background: Taxane-based checkpoint inhibitor combination therapy might improve the outcome in recurrent/metastatic (R/M) head and neck cancer (HNSCC) patients. Thus, we investigated the efficacy and safety of docetaxel (DTX) plus pembrolizumab (P) in a prospective phase I/II trial.

Methods: Platinum-resistant R/M HNSCC patients received DTX 75 mg/m^ plus P 200 mg for up to six cycles followed by P maintenance therapy. The primary endpoint was overall response rate (ORR) and safety. Secondary endpoints comprised disease control rate (DCR), overall survival (OS) and progression free survival (PFS).

Results: Twenty-two patients were enrolled. Nine patients (40.9%) had a primary tumor in the oropharynx, 8 (36.4%) in the oral cavity, 3 (13.6%) in the hypopharynx and 2 (9.1%) in the larynx. The ORR was 22.7% (95% CI 10.1%-43.4%) and one (4.5%) complete response was achieved. The DCR was 54.6% (95% 34.7%-73.1%). The median PFS was 5.8 months (95% CI 2.7-11.6) and the median OS 21.3 months (95% CI 6.3-31.1). The 1-year PFS and OS rates were 27.3% and 68.2%, respectively. While the most frequent adverse event (AE) was myelosuppression, which was reported in all 22 patients, 3 (13.6%) patients experienced grade 3 febrile neutropenia. The most common immune-related AEs were grade skin rash (40.9%) and hypothyroidism (40.9%). One patient (4.5%) experienced grade 5 immune thrombocytopenia.

Conclusion: DXT in combination with P shows promising activity accompanied with a manageable side effect profile in pre-treated R/M HNSCC patients.
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http://dx.doi.org/10.1016/j.oraloncology.2021.105634DOI Listing
January 2022

Pulse-synchronous torsional nystagmus.

Pract Neurol 2021 Oct 16;21(5):445-447. Epub 2021 Jul 16.

Department of Neurology, Medical University of Vienna, Wien, Austria

Purely torsional spontaneous nystagmus almost always has a central vestibular cause. We describe a man with spontaneous pulse-synchronous torsional nystagmus in which the clockwise component corresponded to his pulse upswing, in keeping with a peripheral vestibular cause; following imaging we diagnosed left-sided superior canal dehiscence syndrome. Identifying pulse synchronicity of spontaneous nystagmus may help to distinguish central from peripheral vestibular torsional nystagmus, and is readily confirmed at the bedside using Frenzel's glasses and a pulse oximeter.
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http://dx.doi.org/10.1136/practneurol-2021-003027DOI Listing
October 2021

Titanium and Platinum-Fluoroplastic Stapes Prostheses Visualization on Cone Beam Computed Tomography and High-Resolution Computed Tomography.

Life (Basel) 2021 Feb 17;11(2). Epub 2021 Feb 17.

Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, 1090 Vienna, Austria.

The aim of this study was to evaluate whether stapes prostheses can be visualized with less metal artifacts and therefore more accurately on cone beam computed tomography in comparison to computed tomography imaging. Recent studies have shown that cone beam computed tomography has advantages when imaging metal artifacts. Patients with hearing loss or vertigo, who have undergone stapedotomy, often present a challenge for otologic surgeons. Imaging studies can deliver crucial additional information. A retrospective analysis of imaging studies and clinical data in a tertiary care center were carried out. Forty-one patients with forty-five implanted ears were evaluated in the study. All included patients had been implanted with a platinum-fluoroplastic (n = 19) or titanium (n = 26) piston and subsequently had undergone imaging months or years after surgery for various reasons. Patients underwent computed tomography or cone beam computed tomography of the temporal bone depending on availability. Piston visualization, prosthesis length, vestibular intrusion and audiologic results were compared between the groups. Piston position on imaging studies were compared to intraoperative findings. Functional length measurements of all prostheses were carried out with a mean error of -0.17 mm (±0.20). Platinum-fluoroplastic protheses were significantly underestimated in length compared to titanium prostheses. To analyze the material-dependent difference in the measurement errors of the imaging techniques the interaction was tested in an ANOVA model and showed no statistically significant result ( = 0.24). The blinded neuroradiologist viewed two implants, both platinum-fluoroplastic pistons, as located outside of the vestibule due to an underestimation of the prothesis length and the missing radiodensity of the lower end of the prosthesis. Surgeons and radiologists should be aware of the different types and radiologic features of stapes prostheses and the missing radiodensity of some protheses parts. Cone beam computed tomography is an imaging alternative with a potential advantage of reduced radiation in patients after stapes surgery suffering from vertigo or hearing loss to evaluate piston position.
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http://dx.doi.org/10.3390/life11020156DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923124PMC
February 2021

Radiomics of high-resolution computed tomography for the differentiation between cholesteatoma and middle ear inflammation: effects of post-reconstruction methods in a dual-center study.

Eur Radiol 2021 Jun 4;31(6):4071-4078. Epub 2020 Dec 4.

Department of Biomedical Imaging and Image-guided Therapy, Division of General and Pediatric Radiology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.

Objectives: To evaluate the performance of radiomic features extracted from high-resolution computed tomography (HRCT) for the differentiation between cholesteatoma and middle ear inflammation (MEI), and to investigate the impact of post-reconstruction harmonization and data resampling.

Methods: One hundred patients were included in this retrospective dual-center study: 48 with histology-proven cholesteatoma (center A: 23; center B: 25) and 52 with MEI (A: 27; B: 25). Radiomic features (co-occurrence and run-length matrix, absolute gradient, autoregressive model, Haar wavelet transform) were extracted from manually defined 2D-ROIs. The ten best features for lesion differentiation were selected using probability of error and average correlation coefficients. A multi-layer perceptron feed-forward artificial neural network (MLP-ANN) was used for radiomics-based classification, with histopathology serving as the reference standard (70% of cases for training, 30% for validation). The analysis was performed five times each on (a) unmodified data and on data that were (b) resampled to the same matrix size, and (c) corrected for acquisition protocol differences using ComBat harmonization.

Results: Using unmodified data, the MLP-ANN classification yielded an overall median area under the receiver operating characteristic curve (AUC) of 0.78 (0.72-0.84). Using original data from center A and resampled data from center B, an overall median AUC of 0.88 (0.82-0.99) was yielded, while using ComBat harmonized data, an overall median AUC of 0.89 (0.79-0.92) was revealed.

Conclusion: Radiomic features extracted from HRCT differentiate between cholesteatoma and MEI. When using multi-centric data obtained with differences in CT acquisition parameters, data resampling and ComBat post-reconstruction harmonization clearly improve radiomics-based lesion classification.

Key Points: • Unenhanced high-resolution CT coupled with radiomics analysis may be useful for the differentiation between cholesteatoma and middle ear inflammation. • Pooling of data extracted from inhomogeneous CT datasets does not appear meaningful without further post-processing. • When using multi-centric CT data obtained with differences in acquisition parameters, post-reconstruction harmonization and data resampling clearly improve radiomics-based soft-tissue differentiation.
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http://dx.doi.org/10.1007/s00330-020-07564-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8128805PMC
June 2021

Matrix-associated chondrocyte transplantation for reconstruction of articulating surfaces in the temporomandibular joint: a pilot study covering medium- and long-term outcomes of 6 patients.

Oral Surg Oral Med Oral Pathol Oral Radiol 2018 08 9;126(2):117-128. Epub 2018 Mar 9.

Department of Oral and Maxillofacial Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.

Objective: Matrix-associated chondrocyte transplantation is routinely used in joints of the extremities but not in the temporomandibular joint (TMJ).

Study Design: We report the first case series in 7 patients of a tissue engineering approach to regenerate severely degraded articulating surfaces in the TMJ by simultaneously completely resurfacing both the mandibular condyle and the articular eminence/glenoid fossa with a commercially available collagen sponge seeded with autologous cells stabilized within a fibrin matrix. To facilitate healing, we temporarily employed a silicone membrane to protect the engineered tissues. The indications for surgery were posttraumatic fibro-osseous ankylosis, ankylosing osteoarthritis, or late-stage osteoarthritis.

Results: Six of the patients were recalled for follow-up after 3 years 6 months to 12 years 1 month. The maximum incisal opening was 18.2 ± 9.2 mm (range, 9-33 mm) before and 31.2 ± 13.6 mm (range, 12-47 mm) at the latest follow-up. Histologic specimens taken at 4 months showed beginning differentiation of fibrocytes into chondrocytes, whereas at 3 and 11 years, mature hyaline cartilage-not typical for the TMJ-was present.

Conclusions: We conclude that the reconstruction of TMJ surfaces by matrix-associated chondrocyte transplantation may become a routine method for cartilage regeneration in the TMJ in the future.
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http://dx.doi.org/10.1016/j.oooo.2018.02.017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6057608PMC
August 2018

TrueFisp versus HASTE sequences in 3T cine MRI: Evaluation of image quality during phonation in patients with velopharyngeal insufficiency.

Eur Radiol 2016 Sep 28;26(9):2892-8. Epub 2015 Nov 28.

Department of Cranio-, Maxillofacial and Oral Surgery, Medical University Vienna, Vienna, Austria.

Objective: To evaluate the image quality of two fast dynamic magnetic resonance imaging (MRI) sequences: True fast imaging with steady state precession (TrueFisp) was compared with half-Fourier acquired single turbo-spin-echo (HASTE) sequence for the characterization of velopharyngeal insufficiency (VPI) in repaired cleft palate patients.

Methods: Twenty-two patients (10 female and 12 male; mean age, 17.7 ± 10.6 years; range, 9-31) with suspected VPI underwent 3-T MRI using TrueFisp and HASTE sequences. Imaging was performed in the sagittal plane at rest and during phonation of "ee" and "k" to assess the velum, tongue, posterior pharyngeal wall and a potential VP closure. The results were analysed independently by one radiologist and one orthodontist.

Results: HASTE performed better than TrueFisp for all evaluated items, except the tongue evaluation by the orthodontist during phonation of "k" and "ee". A statistically significant difference in favour of HASTE was observed in assessing the velum at rest and during phonation of "k" and "ee", and also in assessing VP closure in both raters (p < 0.05). TrueFisp imaging was twice as fast as HASTE (0.36 vs. 0.75 s/image).

Conclusion: Dynamic HASTE images were of superior quality to those obtained with TrueFisp, although TrueFisp imaging was twice as fast.

Key Points: • Dynamic MRI is an invaluable tool for diagnosing VPI. • Dynamic HASTE images were of superior quality to those obtained with TrueFisp. • TrueFisp imaging was twice as fast as HASTE imaging.
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http://dx.doi.org/10.1007/s00330-015-4115-3DOI Listing
September 2016

Use of diagnostic dynamic contrast-enhanced (DCE)-MRI for targeting of soft tissue tumour biopsies at 3T: preliminary results.

Eur Radiol 2015 Jul 11;25(7):2041-8. Epub 2015 Jan 11.

Department of Biomedical Imaging and Image-guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology, Medical University of Vienna, Vienna, Austria,

Objectives: 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.

Methods: 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).

Results: 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]).

Conclusions: 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.

Key Points: • 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.
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http://dx.doi.org/10.1007/s00330-014-3576-0DOI Listing
July 2015

Rapid detection of bone metastasis at thoracoabdominal CT: accuracy and efficiency of a new visualization algorithm.

Radiology 2014 Mar 10;270(3):825-33. Epub 2013 Dec 10.

From the Departments of Radiology (D.F.T., M.T., M.E.M., J.F., U.A., M.W., C.C., C.J.H., H.R.) and Nuclear Medicine (G.K.), Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria; and Department of Radiology, Duke University School of Medicine, Durham, NC (G.D.R.).

Purpose: To retrospectively assess the use of a combination of cancellous bone reconstructions (CBR) and multiplanar reconstructions (MPRs) for the detection of bone metastases at thoracoabdominal computed tomography (CT) compared with the use of MPRs alone.

Materials And Methods: The study was approved by the local institutional review board. Included were 156 consecutive patients with confirmed cancer who underwent a whole-body positron emission tomography (PET)/CT examination for clinical purposes (93 male and 63 female patients; mean age ± standard deviation, 59.8 years ± 14.9; range, 11-85 years). Only the CT images were processed with the CBR algorithm, which segments the bones and removes the cortical layer from the images. The PET images served as part of the reference standard. Images from 15 patients were used as a training set. Four radiologists independently evaluated images of half of the remaining 141 patients by using CBRs and MPRs together, and the other half by using MPRs only. Radiologists were blinded to patient names, and patient order was randomized. Results for detection rates and reporting time were recorded and compared with a standard of reference for each patient that was created by one senior radiologist and one nuclear medicine specialist by using all available CT and PET data, CBRs, and follow-up examinations. General estimation equations were used for statistical analysis.

Results: There were 349 lesions found in 103 patients, with 203 classified as malignant. Each patient was assessed by two readers per method, leading to a total of 698 lesions. The detection rate for all bone lesions was 35% (247 of 698) for MPRs and 74% (520 of 698) when CBRs and MPRs were used together, which was significantly higher (P < .001). The average reading time decreased from 85 to 43 seconds (P < .001) when both reconstructions were used.

Conclusion: Advanced visualization of cancellous bone significantly increased the detection of bone metastases and reduced the time for interpretation.
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http://dx.doi.org/10.1148/radiol.13130789DOI Listing
March 2014

Can dual-energy CT improve the assessment of tumor margins in oral cancer?

Oral Oncol 2014 Mar 25;50(3):221-7. Epub 2013 Dec 25.

University Clinic of Craniomaxillofacial and Oral Surgery, Medical University of Vienna, Austria. Electronic address:

Objectives: The aim was to investigate the image quality of dual-energy computed-tomography (DECT) compared to single-energy images at 80 kV and 140 kV in oral tumors.

Materials And Methods: Forty patients underwent a contrast-enhanced DECT scan on a definition flash-CT. Four reconstructions (80 kV, 140 kV, mixed (M), and optimum-contrast (OC)) were assessed by four blinded readers for subjective image quality (10-point scale/10=best). For objective quality assessment, linear attenuation measurements (line density profiles (LDP)) were positioned at the tumor margin, and the difference between minimum and maximum was calculated. Signal-to-noise ratios (SNR) were measured in the tongue.

Results: The mean image quality for all readers was 5.1±0.3, 8.4±0.3, 8.1±0.2, and 8.3±0.2 for the 140 kV, 80 kV, M, and OC, respectively (P<001 between 140 kV and all others). The mean difference between the minimum and maximum within the LDP was 139.4±59.0, 65.7±29.5, 105.1±46.5, and 118.7±59.4 for the 80 kV, 140 kV, M, and OC, respectively (P<001). The SNR for the tongue was 3.8±2.1, 3.8±2.1, 4.2±2.4, and 4.1±2.3 for the 80 kV, 140 kV, M, and OC, respectively.

Discussion: DECT of oral tumors offers high image quality, with subjectively rated image quality and attenuation contrast at the tumor margin similar to that of 80 kV; DECT, however, provides a significantly higher SNR compared to 80 kV.
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http://dx.doi.org/10.1016/j.oraloncology.2013.12.001DOI Listing
March 2014

Texture-based and diffusion-weighted discrimination of parotid gland lesions on MR images at 3.0 Tesla.

NMR Biomed 2013 Nov 23;26(11):1372-9. Epub 2013 May 23.

Medical University of Vienna, Department of Radiology, Subdivision of Neuroradiology and Musculoskeletal Radiology, Vienna, Austria.

The purpose of this study was to evaluate whether texture-based analysis of standard MRI sequences and diffusion-weighted imaging can help in the discrimination of parotid gland masses. The MR images of 38 patients with a biopsy- or surgery-proven parotid gland mass were retrospectively analyzed. All patients were examined on the same 3.0 Tesla MR unit, with one standard protocol. The ADC (apparent diffusion coefficient) values of the tumors were measured with three regions of interest (ROIs) covering the entire tumor. Texture-based analysis was performed with the texture analysis software MaZda (version 4.7), with ROI measurements covering the entire tumor in three slices. COC (co-occurrence matrix), RUN (run-length matrix), GRA (gradient), ARM (auto-regressive model), and WAV (wavelet transform) features were calculated for all ROIs. Three subsets of 10 texture features each were used for a linear discriminant analysis (LDA) in combination with k nearest neighbor classification (k-NN). Using histology as a standard of reference, benign tumors, including subtypes, and malignant tumors were compared with regard to ADC and texture-based values, with a one-way analysis of variance with post-hoc t-tests. Significant differences were found in the mean ADC values between Warthin tumors and pleomorphic adenomas, as well as between Warthin tumors and benign lesions. Contrast-enhanced T1-weighted images contained the most relevant textural information for the discrimination between benign and malignant parotid masses, and also for the discrimination between pleomorphic adenomas and Warthin tumors. STIR images contained the least relevant texture features, particularly for the discrimination between pleomorphic adenomas and Warthin tumors. Texture analysis proved to differentiate benign from malignant lesions, as well as pleomorphic adenomas from Warthin tumors, based on standard T(1w) sequences (without and with contrast). Of all benign parotid masses, Warthin tumors had significantly lower ADC values than the other entities.
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http://dx.doi.org/10.1002/nbm.2962DOI Listing
November 2013

Imaging in patients with merkel cell carcinoma.

J Skin Cancer 2013 6;2013:973123. Epub 2013 Feb 6.

Department of Otolaryngology Head and Neck Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.

Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine tumor of the skin with a mortality rate of approximately 25% (Peloschek et al., 2010). Accurate assessment of nodal involvement in patients with MCC predicts significantly overall outcome (Smith et al., 2012 and Ortin-Perez et al., 2007). Due to the rarity of this highly aggressive disease, only a few imaging reports on MCC were published, and subsequently still to date no accepted imaging algorithm for MCC is available. For primary staging of MCC, general recommendations have included ultrasonography, chest X-ray CT, and MRI, but recent articles show that the use of sentinel node and FDG-PET/PET-CT is gaining more and more importance.
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http://dx.doi.org/10.1155/2013/973123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3580906PMC
March 2013

Intracranial hematomas at a glance: advanced visualization for fast and easy detection.

Radiology 2013 May 13;267(2):522-30. Epub 2012 Dec 13.

Departments of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.

Purpose: To retrospectively assess the detection rate for intracranial hematomas achieved with use of curved maximum intensity projections (MIPs) that parallel the inner table of the skull compared with the rate achieved by reading transverse sections of computed tomography (CT) only.

Materials And Methods: This retrospective study was approved by the institutional review board, which waived informed consent. A total of 314 consecutive patients who underwent CT for cranial trauma (155 male, 159 female; mean age ± standard deviation, 58 years ± 24 [range, 2-98 years]) were included. The algorithm unfolded the meningeal spaces into four images per patient. Four radiologists independently evaluated all cases. Hematomas less than 3 mm thick were considered thin. Radiologists were blinded to patient names, and patient and group orders were randomly assigned. The results were compared with a reference standard built by two experts. Logistic regression with repeated measurements was used for statistical analysis.

Results: Use of the reference standard helped confirm 121 intracranial hematomas in 39 patients. For all readers, reading time for hematoma detection was significantly shorter (3-5 times shorter, P < .001) for curved MIPs. Mean lesion-based detection rate for all readers was 80% (193 of 242) for transverse sections and 83% (200 of 242) for curved MIPs. For thin hematomas, the mean detection rate increased from 20% (eight of 40) with transverse sections to 83% (33 of 40) with curved MIPs.

Conclusion: Curved MIPs of the meningeal spaces may shorten detection time for epidural and subdural hematomas, increase sensitivity (especially for thin hematomas), and reduce the required operator experience for detection.
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http://dx.doi.org/10.1148/radiol.12112389DOI Listing
May 2013

Endolymphatic sac tumor and angiomatous lesions of the nasal and pharyngeal mucosa as a first manifestation of von Hippel-Lindau disease.

Laryngoscope 2012 Oct 9;122(10):2300-3. Epub 2012 Jul 9.

Department of Otorhinolaryngology, Medical University of Vienna, Vienna, Austria.

In the present article we report an endolymphatic sac tumor in a 15-year-old male who had additional angiomatous lesions in the nasal and pharyngeal mucosa and was diagnosed with von Hippel-Lindau disease postoperatively. Preoperative imaging excluded cholesteatoma, but did not provide sufficient information to distinguish between jugular paraganglioma and endolymphatic sac tumor. To the authors' knowledge this is the first description of angiomatous lesions in the mucosa of the upper respiratory tract in a von Hippel-Lindau disease patient, a potentially useful finding for future radiological differential diagnosis in cases presenting with endolymphatic sac tumor.
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http://dx.doi.org/10.1002/lary.23438DOI Listing
October 2012

Maxillary dental arch biometry: assessment with fetal MR imaging.

Prenat Diagn 2012 Jun 17;32(6):530-5. Epub 2012 Apr 17.

Department of Obstetrics and Gynecology, Medical University of Vienna, Austria.

Objective: To define normal growth of the fetal maxillary dental arch using magnetic resonance imaging.

Method: Four hundred twenty-four consecutive fetuses (18 to 37 weeks) with a morphologically normal anatomy or only minor malformations, not affecting bone growth and face anatomy were included. On axial T2-weighted images the dental arch length and width were measured. The measurements were correlated with gestational age and the biparietal diameter (BPD) of the fetal head using correlation and regression analysis.

Results: A linear growth relationship was observed between the dental arch length and gestational age (r = 0.86; p = < 0.0001; y = -1.85 + 0.75 × gestational age) and the dental arch width and gestational age (r = 0.92; p = < 0.0001; y = -2.19 + 1.05 × gestational age). A significant correlation was found between the dental arch length and the BPD (r = 0.903; p = < 0.0001) and the dental arch width and the BPD (r = 0.927; p = < 0.0001). The interobserver variability showed good agreement for the dental arch length (intraclass coefficient 0.981; r = 0.963) and width (intraclass coefficient 0.987; r = 0.974), respectively.

Conclusion: We present a nomogram for the in utero assessment of the fetal dental arch. These data may help in the early detection of abnormal dental arch development.
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http://dx.doi.org/10.1002/pd.3851DOI Listing
June 2012

Quantitative evaluation of contrast-enhanced ultrasound after intravenous administration of a microbubble contrast agent for differentiation of benign and malignant thyroid nodules: assessment of diagnostic accuracy.

Eur Radiol 2012 Jun 10;22(6):1357-65. Epub 2012 Feb 10.

Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.

Objectives: To investigate the diagnostic accuracy, through quantitative analysis, of contrast-enhanced ultrasound (CEUS), using a microbubble contrast agent, in the differentiation of thyroid nodules.

Methods: This prospective study enrolled 46 patients with solitary, scintigraphically non-functional thyroid nodules. These patients were scheduled for surgery and underwent preoperative CEUS with pulse-inversion harmonic imaging after intravenous microbubble contrast medium administration. Using histology as a standard of reference, time-intensity curves of benign and malignant nodules were compared by means of peak enhancement and wash-out enhancement relative to the baseline intensity using a mixed model ANOVA. ROC analysis was performed to assess the diagnostic accuracy in the differentiation of benign and malignant nodules on CEUS.

Results: The complete CEUS data of 42 patients (31/42 [73.8%] benign and 11/42 [26.2%] malignant nodules) revealed a significant difference (P < 0.001) in enhancement between benign and malignant nodules. Furthermore, based on ROC analysis, CEUS demonstrated sensitivity of 76.9%, specificity of 84.8% and accuracy of 82.6%.

Conclusions: Quantitative analysis of CEUS using a microbubble contrast agent allows the differentiation of benign and malignant thyroid nodules and may potentially serve, in addition to grey-scale and Doppler ultrasound, as an adjunctive tool in the assessment of patients with thyroid nodules.

Key Points: • Contrast-enhanced ultrasound (CEUS) helps differentiate between benign and malignant thyroid nodules. • Quantitative CEUS analysis yields sensitivity of 76.9% and specificity of 84.8%. • CEUS may be a potentially useful adjunct in assessing thyroid nodules.
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http://dx.doi.org/10.1007/s00330-012-2385-6DOI Listing
June 2012

MRI versus radiography of acromioclavicular joint dislocation.

AJR Am J Roentgenol 2011 Oct;197(4):968-73

Department of Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.

Objective: Acromioclavicular joint injuries are usually diagnosed by clinical and radiographic assessment with the Rockwood classification, which is crucial for treatment planning. In view of the implementation of MRI for visualization of the acromioclavicular joint, the purpose of this study was to describe the MRI findings of acromioclavicular joint dislocation in comparison with the radiographic findings.

Subjects And Methods: Forty-four patients with suspected unilateral acromioclavicular joint dislocation after acute trauma were enrolled in this prospective study. All patients underwent digital radiography and 1-T MRI with a surface phased-array coil. MRI included coronal proton density-weighted turbo spin-echo and coronal 3D T1-weighted fast field-echo water-selective sequences. The Rockwood classification was used to assess acromioclavicular joint injuries at radiography and MRI. An adapted Rockwood classification was used for MRI evaluation of the acromioclavicular joint ligaments. The classifications of acromioclavicular joint dislocations diagnosed with radiography and MRI were compared.

Results: Among 44 patients with Rockwood type I-IV injuries on radiographs, classification on radiographs and MR images was concordant in 23 (52.2%) patients. At MRI, the injury was reclassified to a less severe type in 16 (36.4%) patients and to a more severe type in five (11.4%) patients. Compared with the findings according to the original Rockwood system, with the adapted system that included MRI findings, additional ligamentous lesions were found in 11 (25%) patients.

Conclusion: In a considerable number of patients, the MRI findings change the Rockwood type determined with radiography. In addition to clinical assessment and radiography, MRI may yield important findings on ligaments that may influence management.
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http://dx.doi.org/10.2214/AJR.10.6378DOI Listing
October 2011

Functional imaging in head and neck squamous cell carcinoma: correlation of PET/CT and diffusion-weighted imaging at 3 Tesla.

Eur J Nucl Med Mol Imaging 2011 Jun 5;38(6):1009-19. Epub 2011 Apr 5.

Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, 1090 Vienna, Austria.

Purpose: The purposes of this study were: (a) to prospectively assess the correlation between apparent diffusion coefficient (ADC) values and maximum standardized uptake values (SUVmax) in patients with head and neck squamous cell carcinomas (SCC); and (b) to assess ADC and SUVmax values in relation to different tumour grades and stages in our patient population.

Methods: The study group comprised 31 consecutive patients with biopsy-proven head and neck squamous cell carcinoma who were examined using a 3T MRI scanner with a 16-channel head and neck coil. In addition to routine sequences, axial (DWIBS) and sagittal (DW-EPI) diffusion-weighted sequences were obtained using b-values of 0 mm(2)/s and 800 mm(2)/s. The ADC maps were calculated automatically. The ADC values of the tumours were measured with three regions of interest (ROIs) of standard size, and an ROI covering the entire tumour. In all patients, contrast-enhanced, whole-body (18)F-FDG PET/CT was performed within 2 weeks of the MRI examination. SUVmax was measured for every tumour using a 3-D freehand ROI that covered the entire tumour. Two-way repeated measures ANOVA was used for group comparisons. The Spearman rank correlation test was performed for ADC values.

Results: Mean ADC values in the 31 SCC were 0.902 (± 0.134) with a ROI of standard size, and 0.928 (± 0.160) with the large ROI measurements on the axial DWIBS sequence. The ADC values of the tumours were significantly higher when measured with the sagittal DW-EPI sequence: 1.051 (± 0.211) and 1.082 (± 0.208). We observed no significant differences in ADC values and SUVmax between the various T stages or histological grades of the tumours. SUVmax values (26.5 ± 12) did not correlate with ADC values on DWIBS or EPI.

Conclusion: There is no correlation between the FDG uptake and the ADC value in head and neck SCC. The three different tumour grades and four tumour stages present in our study population could not be differentiated based on ADC values or SUV.
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http://dx.doi.org/10.1007/s00259-010-1718-4DOI Listing
June 2011

The skull unfolded: a cranial CT visualization algorithm for fast and easy detection of skull fractures.

Radiology 2010 May 23;255(2):553-62. Epub 2010 Mar 23.

Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.

Purpose: To retrospectively assess the rate of detection of skull fractures at cranial computed tomography (CT) achieved with the use of curved maximum intensity projections (MIPs) compared with that achieved by reading transverse sections only.

Materials And Methods: The institutional review board approved this research and waived informed consent. A curved thin (3-mm) MIP of the skull cap and a curved thick (50-mm) MIP of the skull base were obtained from the cranial CT data in 200 consecutive patients with head trauma. Four radiologists (two residents without experience in cranial CT and two consultants) independently evaluated all cases. Each radiologist reported findings in 100 patients by using transverse sections only and findings in the other 100 patients by using the unfolded view. The radiologists were blinded to patient names, and patient and group orders were randomized. The results were compared with a standard of reference established by two experts from all prior reading results, all reconstructions, and high-spatial-resolution multiplanar reformats. Logistic regression with repeated measurements was used for statistical analysis.

Results: The experts found 63 fractures in 30 patients. When transverse sections only were used, the mean patient-based fracture detection rate was 43% (13 of 30) for inexperienced and 70% (21 of 30) for experienced readers; with curved MIPs, the rates were 80% (24 of 30) and 87% (26 of 30), respectively. Overall sensitivity was higher with curved MIPs (P < .001); specificity was higher with transverse sections (P < .001).

Conclusion: Curved MIPs enable a significantly higher fracture detection rate than transverse sections. They also considerably close the experience gap in fracture detection rate between residents and experts.
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http://dx.doi.org/10.1148/radiol.10091096DOI Listing
May 2010

The story of 12 Chachapoyan mummies through multidetector computed tomography.

Eur J Radiol 2010 Nov 6;76(2):143-50. Epub 2009 Aug 6.

Medical University Vienna, Department of Radiology, Waehringer Guertel 18-20, Vienna, Austria.

Objective: To assess the imaging findings in Chachapoyan mummies of Peru through multidetector computed tomography (MDCT).

Materials And Methods: Twelve human mummies and three burial objects from Laguna de los Cóndores, Peru, about 500-1000 years old, were studied, using a MDCT unit. In addition to the standard whole-body acquisitions, high-resolution scans from areas of particular interest were acquired individually (e.g., temporal bone, teeth).

Results: Eight mummies were female, three male, and sex was indeterminable in one mummy; the age of the mummies included newborn, 0.7 years, 2.5 years, 13 years, 13 years, 16 years, and six between 20 and 40 years old. The stature of the mummies was reconstructed (mean±standard deviation; adults: 145±14cm, adolescents: 116±17cm, 2.5 years old child: 72cm, newborns: 41±3cm). Dental conditions were compromised in seven and excellent in five mummies. Besides a dislocation of the ossicles, temporal bones and ears were normal in all mummies. An occipital osteoma, a tuberculous spondylodiscitis, and also probable tuberculous erosions at one tarsal joint and one sacral bone, osteoarthritis or tuberculous affection of a sacroiliac joint, as well as five cases of pulmonary tuberculosis were observed. Ten mummies were buried in the fetal position, two were found packaged in bundles; the burial technique was studied in detail. A necklace was found with one mummy. The added burial objects were identified as skeletal parts of two leopardis pardalis and one lagothrix flavicauda.

Conclusions: MDCT non-invasively revealed information about age, sex, stature, diseases, burial practices and other cultural aspects of the Chachapoyas.
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http://dx.doi.org/10.1016/j.ejrad.2009.07.009DOI Listing
November 2010

Three-dimensional fracture visualisation of multidetector CT of the skull base in trauma patients: comparison of three reconstruction algorithms.

Eur Radiol 2009 Oct 14;19(10):2416-24. Epub 2009 May 14.

Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, Vienna, 1090, Austria.

The purpose of this study was to retrospectively assess the detection rate of skull-base fractures for three different three-dimensional (3D) reconstruction methods of cranial CT examinations in trauma patients. A total of 130 cranial CT examinations of patients with previous head trauma were subjected to 3D reconstruction of the skull base, using solid (SVR) and transparent (TVR) volume-rendering technique and maximum intensity projection (MIP). Three radiologists independently evaluated all reconstructions as well as standard high-resolution multiplanar reformations (HR-MPRs). Mean fracture detection rates for all readers reading rotating reconstructions were 39, 36, 61 and 64% for SVR, TVR, MIP and HR-MPR respectively. Although not significantly different from HR-MPR with respect to sensitivity (P = 0.9), MIP visualised 18% of fractures that were not reported in HR-MPR. Because of the relatively low detection rate using HR-MPRs alone, we recommend reading MIP reconstructions in addition to the obligatory HR-MPRs to improve fracture detection.
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http://dx.doi.org/10.1007/s00330-009-1435-1DOI Listing
October 2009

Diagnostic value of sonography, ultrasound-guided fine-needle aspiration cytology, and diffusion-weighted MRI in the characterization of cold thyroid nodules.

Eur J Radiol 2010 Mar 4;73(3):538-44. Epub 2009 Feb 4.

Department of Diagnostic Radiology, Medical University of Vienna, Waehringer Guertel, Vienna, Austria.

Introduction: The purpose of this prospective study was to assess the diagnostic value of different modalities for the characterization of cold thyroid nodules.

Methods: In 35 patients with cold nodules, thyroid carcinoma was suspected on scintigraphy. These patients were prospectively investigated with sonography, ultrasound-guided fine-needle aspiration (USgFNA), and quantitative diffusion-weighted imaging magnetic resonance imaging (DWI) (navigated echo-planar imaging; maximum b-value 800s/mm(2)) prior to surgery. The sonographic findings, USgFNA cytology, and the apparent diffusion coefficient (ADC) values of DWI were correlated with the postoperative histology of benign and malignant lesions. Statistical analysis was performed with the Kruskal-Wallis test and the Fisher's exact test. P<.05 denoted statistical significance.

Results: The accuracy of sonography and USgFNA was 64% and 68.8%, respectively. The sensitivity was 86.7% and 80%, respectively. Specificity was only 57.2% and 50%, respectively. The median ADC values for carcinoma and adenoma were 2.73 x 10(-3)mm(2)/s and 1.93 x 10(-3)mm(2)/s, respectively (P<.001). There was no significant difference between the median ADC value for Hashimoto thyroiditis (3.46 x 10(-3)mm(2)/s) and carcinoma. An ADC value of 2.25 x 10(-3)mm(2)/s or higher was proven to be the cut-off value for differentiating between benign and malignant cold thyroid nodules, with an accuracy of 88%, a sensitivity of 85%, and a specificity of 100%.

Conclusions: These results show that quantitative DWI is a more reliable diagnostic method for differentiation between benign and malignant thyroid lesions than sonography or USgFNA. However, further studies including a larger study population are necessary to confirm our study results.
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http://dx.doi.org/10.1016/j.ejrad.2008.12.013DOI Listing
March 2010

Diffusion-weighted magnetic resonance imaging of head and neck squamous cell carcinomas.

Eur J Radiol 2008 Dec;68(3):493-8

Medical University Vienna, Department of Radiology, Division of MSK- and Neuroradiology, Waehringer Guertel 18-20, A-1090 Vienna, Austria.

Objective: To evaluate whether diffusion-weighted imaging (DWI) is a reliable technique to quantify microstructural differences between head and neck squamous cell carcinomas (SCC) and tumour-free soft tissue.

Materials And Methods: DWI was obtained from 20 patients with histologically proven, untreated head and neck SCC. DWI was acquired using a diffusion-weighted, navigated echo-planar imaging sequence with a maximum b-value of 800 s/mm2. For an objective assessment of image quality, the signal-to-noise ratio (SNR) was calculated. Microstructural differences between vital tumour tissue and tumour-free soft tissue were quantified by calculating the apparent-diffusion-coefficients (ADC) on a pixel by pixel method.

Results: Echo-planar DWI provided good image quality in all patients (mean SNR 18.4). The mean ADC of SCC, (0.64+/-0.28 x 10(-3) mm2/s), was significantly (P<0.0001) lower than that of the tumour-free soft tissue, (2.51+/-0.82 x 10(-3) mm2/s).

Conclusion: DWI is a reliable diagnostic tool to quantify the microstructural differences between vital tumour tissue and tumour-free soft tissue in patients with head and neck SCC.
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http://dx.doi.org/10.1016/j.ejrad.2007.10.011DOI Listing
December 2008

Diagnostic imaging in Merkel cell carcinoma: lessons to learn from 16 cases with correlation of sonography, CT, MRI and PET.

Eur J Radiol 2010 Feb 23;73(2):317-23. Epub 2008 Dec 23.

Department of Radiology, Medical University of Vienna, Austria.

Objective: The authors report imaging findings in a series of 16 patients with MCC, a rare tumour which is often managed primarily by a dermatologist. To our knowledge, no equivalent series of MCC has been described in the nuclear medicine literature.

Material And Methods: In this IRB-approved retrospective noncomparative case series 16 patients with biopsy-proven Merkel cell carcinoma were included between January 1999 and October 2007. Twenty-nine whole body PET scans (18F-FDG n=24, 18F-FDOPA n=5) in 16 patients were retrospectively reviewed with regard to tracer uptake in six anatomical sites per patient. For 127/144 of FDG-PET evaluated regions and 68/144 of regions depicted by conventional imaging methods, a valid standard of reference could be obtained. A combined standard of reference was applied, which consisted of histopathology (lymphadenectomy or biopsy) or clinical or radiological follow-up for at least 12 months.

Results: the mean FDG uptake over the clinicopatholigical verified FDG avid areas was 4.7 SUV (1.5-9.9 SUV). The region based assessment of diagnostic value, in consideration of the standard of reference, resulted in a sensitivity of 85.7% and a specificity of 96.2% of FDG-PET (n=127) and in a combined sensitivity of 95.5% and a specificity of 89.1% for morphological imaging methods (n=68). Differences between methods did not reach statistical significance (p=1.00, p=0.18).

Conclusions: FDG-PET is a highly useful whole body staging method of comparable value compared to conventional imaging methods with restricted field of view. The lessons learned from case series are discussed.
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http://dx.doi.org/10.1016/j.ejrad.2008.10.032DOI Listing
February 2010

CT-MR image data fusion for computer-assisted navigated surgery of orbital tumors.

Eur J Radiol 2010 Feb 20;73(2):224-9. Epub 2008 Dec 20.

Department of Radiology/Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringerguertel 18-20, A-1090 Vienna, Austria.

Purpose: To demonstrate the value of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative assessment of orbital tumors, and to present, particularly, CT and MR image data fusion for surgical planning and performance in computer-assisted navigated surgery of orbital tumors.

Materials And Methods: In this retrospective case series, 10 patients with orbital tumors and associated complaints underwent MDCT and MRI of the orbit. MDCT was performed at high resolution, with a bone window level setting in the axial plane. MRI was performed with an axial 3D T1-weighted (w) gradient-echo (GE) contrast-enhanced sequence, in addition to a standard MRI protocol. First, MDCT and MR images were used to diagnose tumorous lesions compared to histology as a standard of reference. Then, the image data sets from CT and 3D T1-w GE sequences were merged on a workstation to create CT-MR fusion images that were used for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient. Furthermore, the clinical preoperative status was compared to the patients' postoperative outcome.

Results: Radiological and histological diagnosis, which revealed 7 benign and 3 malignant tumors, were concordant in 7 of 10 cases (70%). The CT-MR fusion images supported the surgeon in the preoperative planning and improved the surgical performance. The mean intraoperative accuracy of the navigation unit was 1.35mm. Postoperatively, orbital complaints showed complete regression in 6 cases, were ameliorated notably in 3 cases, and remained unchanged in 1 case.

Conclusion: CT and MRI are essential for the preoperative assessment of orbital tumors. CT-MR image data fusion is an accurate tool for planning the correct surgical procedure, and can improve surgical results in computer-assisted navigated surgery of orbital tumors.
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http://dx.doi.org/10.1016/j.ejrad.2008.11.003DOI Listing
February 2010

Perineural tumor spread in malignant head and neck tumors.

Top Magn Reson Imaging 2007 Dec;18(6):467-71

Division of Neuroradiology and Musculoskeletal Radiology, Department of Radiology, Medical University of Vienna, Austria.

Perineural tumor spread (PNS) of head and neck malignancies is a course of disease in which tumor metastasizes along the endoneurium or perineurium. Perineural tumor spread is a potentially devastating complication of head and neck cancer and has a high impact on the therapeutical management and overall prognosis. Imaging plays an important role in the detection of this condition, especially in view of a large number of clinically asymptomatic patients with PNS. Magnetic resonance imaging is the modality of choice in the assessment of PNS because of its multiplanar capability and its superior soft-tissue contrast. Knowledge of normal cranial nerve anatomy and the imaging appearance of perineural tumor extension is imperative in the evaluation of PNS which represents a special challenge in head and neck radiology.
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http://dx.doi.org/10.1097/rmr.0b013e3181645a0dDOI Listing
December 2007

Sinonasal imaging after Caldwell-Luc surgery: MDCT findings of an abandoned procedure in times of functional endoscopic sinus surgery.

Eur J Radiol 2009 Apr 25;70(1):31-4. Epub 2008 Feb 25.

Department of Radiology, Division of Neuroradiology and Musculoskeletalradiology, Medical University of Vienna, Waehringerguertel 18-20, 1090 Vienna, Austria.

Background And Purpose: Today, functional endoscopic sinus surgery (FESS) is performed in most of the patients with sinonasal inflammatory disease. The postoperative imaging findings of FESS in multidetector computed tomography (MDCT) considerably differ from those of historic Caldwell-Luc (CL) maxillary sinus surgery which is an uncommon procedure today. Thus, the postoperative CL imaging findings may lead to diagnostic confusion and misinterpretation. Therefore, this study explicitly presents the MDCT findings of post-CL patients which have not been described previously.

Methods: Twenty-eight patients with clinically suspected sinusitis and documented history of CL-procedure underwent 16 row MDCT (MDCT Mx8000 IDT Philips) with multiplanar reconstructions of the paranasal sinuses in the axial plane. The following parameters were used: 140kV, 50mAs; 16mmx0.75mm detector collimation; 1mm reconstructed slice thickness; 0.5mm increment. The studies were reconstructed with a bone algorithm (W3000/L600; 1mm slice thickness) in axial plane and coronal plane (3mm slice thickness). The images were retrospectively evaluated for the presence of normal surgery-related and pathological findings.

Results: Surgery-related imaging characteristics presented as follows: an anterior and a medial bony wall defect and sclerosis and sinus wall thickening were observed in all 28/28 cases (100%). Collaps of the sinus cavity was seen in 26/28 cases (92.9%). Furthermore, inflammatory disease of the operated sinus(es) was found in 23/28 cases (82.1%): 14/28 patients (50%) had inflammatory mucosal thickening of the operated sinus(es) as well as of other sinonasal cavities and 9/28 patients (32.1%) had inflammatory mucosal thickening limited to the operated sinus(es). A postoperative mucocele was depicted in 3/28 cases (10.7%). 2/28 patients (7.1%) showed neither maxillary nor other mucosal swelling.

Conclusion: MDCT with multiplanar reconstructions is a precise method to evaluate post-CL patients and helps to differentiate normal surgery-related findings, which may mimic pathology, from real pathological findings.
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http://dx.doi.org/10.1016/j.ejrad.2008.01.007DOI Listing
April 2009

Detection of cutaneous invasion by malignant head and neck tumors with MDCT.

Eur J Radiol 2008 Nov 21;68(2):335-9. Epub 2007 Dec 21.

Department of Radiology, Division of Neuroradiology and Musculoskeletal Radiology, Medical University Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria.

Objective: Cutaneous invasion by direct infiltration and metastasis, in malignant head and neck tumors, has a distinct impact on therapeutic options, especially surgical procedures, curative intent, and overall prognosis. Therefore, the purpose of this study was to determine the diagnostic accuracy of MDCT in detecting cutaneous invasion by malignant head and neck tumors.

Materials And Methods: Nineteen patients with malignant head and neck tumors and clinical suspicion of cutaneous invasion routinely underwent contrast-enhanced 16-row MDCT (Philips MDCT MX 8000) of the region of interest in the axial plane before surgical intervention. The following parameters were used: 16mmx0.75mm detector collimation; 3mm reconstructed slice thickness; 1.5mm increment; 0.75s rotation speed; 120kV, 200mAs; and 100ml non-ionic contrast agent, i.v., with a flow of 2.0ml/s and a scan delay of 50s. The studies were reconstructed with a soft tissue algorithm (W400, L100 HU), and coronal and sagittal planes were also reconstructed. The axial images were retrospectively reviewed in consensus by two radiologists for the evidence of cutaneous invasion blinded to the histological results. The MDCT results were correlated with histology that was obtained by punch biopsy or surgery.

Results: MDCT correctly revealed 11 of 11 cases with cutaneous invasion, and correctly excluded 4 of 8 cases without cutaneous invasion. The diagnostic accuracy of MDCT in detecting cutaneous invasion showed a sensitivity of 100%, a specificity of 50%, and an overall accuracy of 79%.

Conclusion: MDCT reconstructed with a soft tissue algorithm has a good sensitivity and moderate overall accuracy in detecting cutaneous invasion by malignant head and neck tumors.
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http://dx.doi.org/10.1016/j.ejrad.2007.08.033DOI Listing
November 2008

Evaluation of bone surface registration applying a micro-needle array.

J Clin Periodontol 2007 Nov 17;34(11):991-7. Epub 2007 Sep 17.

University Hospital of Cranio-Maxillofacial and Oral Surgery, Medical University of Vienna, Vienna, Austria.

Aim: In this study we present and evaluated a new registration technology for the jaw-bone surface. It is based on a micromechatronic device for the generation of a "mechanical image" of the bone surface by means of an array of micro-needles that are penetrating the soft tissue until they touch the surface of the bone. This "mechanical impression image" is aligned with the CT data set.

Material And Methods: Based on laboratory measurements on 10 specially prepared jawbone models we evaluate the accuracy of this new registration method.

Results: Our measurements of the 10 specimens revealed a maximum overall location error of 0.97 mm (range: 0.35-0.97 mm).

Conclusions: From the technical point of view the presented registration technology has the potential to improve the performance (i.e. accuracy and avoidance of errors) of the registration process for bony structures in selected applications of image-guided surgery.
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http://dx.doi.org/10.1111/j.1600-051X.2007.01143.xDOI Listing
November 2007

Pseudodynamic MRI differs from natural opening of the temporomandibular joint.

Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008 Mar 29;105(3):371-8. Epub 2007 Jun 29.

University Hospital of Cranio-Maxillofacial and Oral Surgery, Medical University of Vienna, Vienna, Austria.

Objective: One step toward motion analysis of the temporomandibular joint is pseudodynamic magnetic resonance imaging (i.e., with stepwise mouth opening controlled by a Burnett device). This study intends to clarify whether and how pseudodynamic motion differs from natural motion. Furthermore, the fixing efficiency (i.e., the reliability of the mechanical connection to the jaw) of the Burnett device was tested.

Study Design: In 10 patients we recorded pseudodynamic opening motions by means of MRI and optical tracking technology (as known from image-guided surgery) synchronously; natural opening motions by spatiotemporal tracking only. The MRI was used to allow for interpretation of the pseudodynamic motion as recorded by means of optoelectronic tracking.

Results: In 3 subjects the pseudodynamic differed from the natural opening in occurrence of a loop (i.e., a short backward motion of the condyle during the opening process that results from the application of the Burnett device and does not correspond to a natural jaw movement). Fifty percent of the opening steps showed unintended motion and thus did not keep the mandible still during the MRI scan.

Conclusion: A method was provided to detect motion during MRI scan using optoelectronic tracking. Pseudodynamic motion may differ from natural motion.
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http://dx.doi.org/10.1016/j.tripleo.2007.02.003DOI Listing
March 2008

CT-MR image data fusion for computer assisted navigated neurosurgery of temporal bone tumors.

Eur J Radiol 2007 May 16;62(2):192-8. Epub 2007 Jan 16.

Department of Radiology/Osteology, Medical University Vienna, Waehringerguertel 18-20, A-1090 Vienna, Austria.

Purpose: To demonstrate the value of multi detector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative work up of temporal bone tumors and to present, especially, CT and MR image fusion for surgical planning and performance in computer assisted navigated neurosurgery of temporal bone tumors.

Materials And Methods: Fifteen patients with temporal bone tumors underwent MDCT and MRI. MDCT was performed in high-resolution bone window level setting in axial plane. The reconstructed MDCT slice thickness was 0.8 mm. MRI was performed in axial and coronal plane with T2-weighted fast spin-echo (FSE) sequences, un-enhanced and contrast-enhanced T1-weighted spin-echo (SE) sequences, and coronal T1-weighted SE sequences with fat suppression and with 3D T1-weighted gradient-echo (GE) contrast-enhanced sequences in axial plane. The 3D T1-weighted GE sequence had a slice thickness of 1mm. Image data sets of CT and 3D T1-weighted GE sequences were merged utilizing a workstation to create CT-MR fusion images. MDCT and MR images were separately used to depict and characterize lesions. The fusion images were utilized for interventional planning and intraoperative image guidance. The intraoperative accuracy of the navigation unit was measured, defined as the deviation between the same landmark in the navigation image and the patient.

Results: Tumorous lesions of bone and soft tissue were well delineated and characterized by CT and MR images. The images played a crucial role in the differentiation of benign and malignant pathologies, which consisted of 13 benign and 2 malignant tumors. The CT-MR fusion images supported the surgeon in preoperative planning and improved surgical performance. The mean intraoperative accuracy of the navigation system was 1.25 mm.

Conclusion: CT and MRI are essential in the preoperative work up of temporal bone tumors. CT-MR image data fusion presents an accurate tool for planning the correct surgical procedure and is a benefit for the operational results in computer assisted navigated neurosurgery of temporal bone tumors.
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http://dx.doi.org/10.1016/j.ejrad.2006.11.029DOI Listing
May 2007
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