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.

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.

Pulse-synchronous torsional nystagmus.

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.

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

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.

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

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.

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

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.

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

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.

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

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.

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.

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.

Maxillary dental arch biometry: assessment with fetal MR imaging.

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.

FOXA1 is a transcriptional activator of Odf2/Cenexin and regulates primary ciliation.

Primary cilia are sensory organelles essential for embryonic and postnatal development, and tissue homeostasis in adulthood. They are generated in a cell cycle-dependent manner and found on most cells of the body. Although cilia formation is intensively investigated virtually nothing is known about the transcriptional regulation of primary ciliation. We used here Odf2/Cenexin, encoding a protein of the mother centriole and the basal body that is mandatory for primary cilia formation, as the target gene for the identification of transcriptional activators. We identified a consensus binding site for Fox transcription factors (TFs) in its promoter region and focused here on the Fox family. We found transcriptional activation of Odf2 neither by FOXO TFs nor by the core TF for multiciliation, FOXJ1. However, we identified FOXA1 as a transcriptional activator of Odf2 by reporter gene assays and qRT-PCR, and showed by qWB that Foxa1 knockdown caused a decrease in ODF2 and CP110 proteins. We verified the binding sequence of FOXA1 in the Odf2 promoter by ChIP. Finally, we demonstrated that knockdown of FOXA1 affected primary cilia formation. We, thus, showed for the first time, that FOXA1 regulates primary ciliation by transcriptional activation of ciliary genes.

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

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^2 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.

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

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.

MRI versus radiography of acromioclavicular joint dislocation.

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.

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

Objective: 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. Methods: 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. Results: 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 (p = 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. Conclusion: 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.

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

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.

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

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.

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

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.

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.

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.

Perineural tumor spread in malignant head and neck tumors.

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.

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

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.