[Updated S2k AWMF guideline on obstructive sialadenitis]. / Aktualisierte AWMF-S2k-Leitlinie zur obstruktiven Sialadenitis.

The update of this guideline was an important step to define standards for the use of sialendoscopy and other emerging minimally invasive techniques for the therapy of sialolithiasis and other obstructive salivary gland diseases. The current actualization was necessary to adapt the diagnostic and therapeutic algorithms to the current scientific knowledge. In this article they are presented in a shortened version with a focus on conservative therapeutic measures which are especially relevant for daily practice.

[Artificial intelligence-based algorithms : Decision-making support for computed tomography of the chest]. / Algorithmen mit künstlicher Intelligenz : Entscheidungsunterstützung für Computertomographien des Thorax.

Artificial intelligence (AI) algorithms are increasingly used in radiology. The main areas of application are, for example, the detection of lung lesions and the diagnosis of chronic obstructive and interstitial lung diseases. The aim of our study was to train and evaluate a package of algorithms that analyze data from computed tomographic (CT) images of the chest and provide quantitative measurements to the radiologist. The following algorithms were trained: lung lesion detection and measurement, lung lobe segmentation, vessel segmentation and measurement, coronary calcium scoring, measurement and density analysis of vertebral bodies. AI-supported algorithms will become part of daily routine of the radiologist in the future. Tasks that do not require medical expertise can be performed by AI. However, our results show that, based on the current accuracy, verification by an experienced radiologist is necessary.

Transhepatic forceps biopsy after PTCD for histological assessment of bile duct stenoses or occlusions.

PURPOSE: The goal of this study was to evaluate the experience of 11 years of wire-guided forceps biopsy via PTCD in patients with obstructive jaundice. MATERIALS AND METHODS: In a retrospective approach, 56 biopsies in 51 patients were analyzed (22 female, 29 male). Data was collected from 2006 to 2016. Mean age was 71 years (range: 34 - 86 years). Data was extracted from dig. Patients' records (KIS, PACS, RIS) to be analyzed in Microsoft Excel. RESULTS: All 56 procedures were technically successful. Stenosis in anastomoses were benign due to scarring in 7 patients and in 9 due to papillitis or others. In 4 patients, results in anastomosis were malignant. In 19 patients without anastomosis, CCC was the diagnosis, thereof 10 klatskin, 9 stenosis in other locations, followed by gastric, pancreatic, and colon carcinoma in 5, 3, and 2 patients. Three patients had a CUP (multimetering in case of more than 1 related category). Overall results were 35 mal. and 16 benign, 76.8 % of all proc. had a correct histopathologic result, and 23.2 % were false negative. Sensitivity was 65.8 %, which results in negative predictive value of 58.1 %. There was no false positive and so specificity was 100 %, as was the positive predictive value. False negative results (no malignancy but clinically and imaging suspect) were corrected by rerunning the procedure, by CT-guided biopsy or by 1 PET-CT. In 1 case the surg. sample brought the result. Minor complications occurred in 8 patients: shivering in 1 case, distinct but hemodynamically not relevant hemobilia in 5 cases, 2 portovenal bleedings. All bleedings were short-term and self-limiting. CONCLUSION: Despite good feasibility, low peri- and post-interv. risk and high validity the forceps biopsy via PTCD is not widely used. For experienced interventionalists, it is an effective method for obtaining histology.

Does formalin fixation influence MSCT/CBCT accuracy?

PURPOSE: Advanced imaging modalities, such as multi-slice computed tomography (MSCT) and cone beam computed tomography (CBCT), greatly facilitate diagnostic medicine. In radiological research, it is important to know how accurately a scanned object is visualized, and whether the methodology leads to image distortion. The objective of this study was to evaluate whether formalin fixation impacted the accuracy of virtual 3D bone models generated via CBCT and MSCT using a software-based evaluation method that excluded human measurement errors. METHODS: A head specimen, with and without formalin preservation, was subjected to MSCT and CBCT scans using the manufacturers' predefined scanning protocols. Digital models of the lower jaw were constructed and superimposed with a master model generated based on optical scanning with an industrial non-contact scanner. Means and standard deviations were calculated to assess accuracy, and a t test was used for comparisons between the fixed and unfixed specimens. RESULTS: The extent of discrepancy between the fixed and unfixed specimens was analyzed using a total of 200 points (n = 200) in each specimen state. The mean deviation between states was 0.01 mm for MSCT (at both 80 and 140 kV). Mean values from CBCT at 0.4 voxel did not differ between states. CONCLUSIONS: Our results suggest that formalin fixation of an anatomical specimen does not substantially affect the accuracy of a three-dimensional image generated with CBCT and MSCT. Thus, fixed specimen can be used in future investigations of 3D models without concerns regarding the accuracy.

[The new German guideline on rhinosinusitis - an abbreviated version]. / Die neue Leitlinie Rhinosinusitis ­ eine Miniaturversion.

At the beginning of this year, the new German guideline on rhinosinusitis was published as a joint guideline of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery and the German College of General Practitioners and Family Physicians. The guideline was designed for the treatment of adult patients with inflammatory diseases of the paranasal sinuses and is addressed to all medical specialties involved in the management of these diseases. The current challenge is the implementation of this guideline in the clinical daily routine. For this purpose, an abbreviated version (miniature) was designed.

Impact of post-processing methods on apparent diffusion coefficient values.

OBJECTIVE: The apparent diffusion coefficient (ADC) is increasingly used as a quantitative biomarker in oncological imaging. ADC calculation is based on raw diffusion-weighted imaging (DWI) data, and multiple post-processing methods (PPMs) have been proposed for this purpose. We investigated whether PPM has an impact on final ADC values. METHODS: Sixty-five lesions scanned with a standardized whole-body DWI-protocol at 3 T served as input data (EPI-DWI, b-values: 50, 400 and 800 s/mm2). Using exactly the same ROI coordinates, four different PPM (ADC_1-ADC_4) were executed to calculate corresponding ADC values, given as [10-3 mm2/s] of each lesion. Statistical analysis was performed to intra-individually compare ADC values stratified by PPM (Wilcoxon signed-rank tests: α = 1 %; descriptive statistics; relative difference/∆; coefficient of variation/CV). RESULTS: Stratified by PPM, mean ADCs ranged from 1.136-1.206 *10-3 mm2/s (∆ = 7.0 %). Variances between PPM were pronounced in the upper range of ADC values (maximum: 2.540-2.763 10-3 mm2/s, ∆ = 8 %). Pairwise comparisons identified significant differences between all PPM (P ≤ 0.003; mean CV = 7.2 %) and reached 0.137 *10-3 mm2/s within the 25th-75th percentile. CONCLUSION: Altering the PPM had a significant impact on the ADC value. This should be considered if ADC values from different post-processing methods are compared in patient studies. KEY POINTS: • Post-processing methods significantly influenced ADC values. • The mean coefficient of ADC variation due to PPM was 7.2 %. • To achieve reproducible ADC values, standardization of post-processing is recommended.

Radiation dose reduction in parasinus CT by spectral shaping.

INTRODUCTION: Spectral shaping aims to narrow the X-ray spectrum of clinical CT. The aim of this study was to determine the image quality and the extent of radiation dose reduction that can be achieved by tin prefiltration for parasinus CT. METHODS: All scans were performed with a third generation dual-source CT scanner. A study protocol was designed using 100 kV tube voltage with tin prefiltration (200 mAs) that provides image noise levels comparable to a low-dose reference protocol using 100 kV without spectral shaping (25 mAs). One hundred consecutive patients were prospectively enrolled and randomly assigned to the study or control group. All patients signed written informed consent. The study protocol was approved by the local Institutional Review Board and applies to the HIPAA. Subjective and objective image quality (attenuation values, image noise, and contrast-to-noise ratio (CNR)) were assessed. Radiation exposure was assessed as volumetric CT dose index, and effective dose was estimated. Mann-Whitney U test was performed for radiation exposure and for image noise comparison. RESULTS: All scans were of diagnostic image quality. Image noise in air, in the retrobulbar fat, and in the eye globe was comparable between both groups (all p > 0.05). CNReye globe/air did not differ significantly between both groups (p = 0.7). Radiation exposure (1.7 vs. 2.1 mGy, p < 0.01) and effective dose (0.055 vs. 0.066 mSv, p < 0.01) were significantly reduced in the study group. CONCLUSION: Radiation dose can be further reduced by 17% for low-dose parasinus CT by tin prefiltration maintaining diagnostic image quality.

[Diagnosis and Management of Vestibular Schwannomas - An Interdisciplinary Challenge]. / Diagnostik und Therapie des Vestibularisschwannoms ­ eine interdisziplinäre Herausforderung.

Vestibular schwannomas expand slowly in the internal auditory canal, in the cerebellopontine angle, inside the cochlear and the labyrinth. Larger tumors can displace and compress the brainstem. With an annual incidence of 1:100 000 vestibular schwannoma represent 6-7% of all intracranial tumors. In the cerebellopontine angle they are by far the most neoplasm with 90% of all lesions located in this region. Magnetic resonance imaging (MRI), audiometry, and vestibular diagnostics are the mainstays of the clinical workup for patients harboring tumors. The first part of this paper delivers an overview of tumor stages, the most common grading scales for facial nerve function and hearing as well as a short introduction to the examination of vestibular function.Upholding or improving quality of life is the central concern in counseling and treating a patient with vestibular schwannoma. Preservation of neuronal function is essential and the management options - watchful waiting, microsurgery and stereotactic radiation - should be custom-tailored to the individual situation of the patient. Continuing interdisciplinary exchange is important to monitor treatment quality and to improve treatment results. Recently, several manuscripts and reviews have been published on the topic of vestibular schwanomma. On the occasion of the 88th annual meeting of the German Society of Oto-rhino-laryngology, Head and Neck surgery a special volume of the journal "HNO" will be printed. Hence this presentation has been designed to deviate from the traditional standard which commonly consists of a pure literature review. The current paper was conceptually woven around a series of interdisciplinary cases which outlines examples for every stage of the disease that show characteristic results for management options to date. Systematic clinical decision pathways have been deduced from our experience and from results reported in the literature. These pathways are graphically outlined after the case presentations. Important criteria for decision making are size and growth rate of the tumor, hearing of the patient and the probability of total tumor resection with preservation of hearing and facial nerve function, age and co-morbidity of the patient, best possible control of vertigo and tinnitus and last but not least the patient's preference and choice. In addition to this, the experience and the results of a given center with each treatment modality will figure in the decision making process.We will discuss findings that are reported in the literature regarding facial nerve function, hearing, vertigo, tinnitus, and headache and reflect on recent studies on their influence on the patient's quality of life. Vertigo plays an essential role in this framework since it is an independent predictor of quality of life and a patient's dependence on social welfare.Pathognomonic bilateral vestibular schwannoma that occur in patients suffering from neurofibromatosis typ-2 (NF2) differ from spontaneous unilateral tumors in their biologic behavior. Treatment of neurofibromatosis type-2 patients requires a multidisciplinary team, especially because of the multitude of separate intracranial and spinal lesions.Off-label chemotherapy with Bevacizumab can stabilize tumor size of vestibular schwannomas and even improve hearing over longer periods of time. Hearing rehabilitation in NF2 patients can be achieved with cochlea and auditory brainstem implants.

Low-Dose CT of the Paranasal Sinuses: Minimizing X-Ray Exposure with Spectral Shaping.

OBJECTIVES: Shaping the energy spectrum of the X-ray beam has been shown to be beneficial in low-dose CT. This study's aim was to investigate dose and image quality of tin filtration at 100 kV for pre-operative planning in low-dose paranasal CT imaging in a large patient cohort. METHODS: In a prospective trial, 129 patients were included. 64 patients were randomly assigned to the study protocol (100 kV with additional tin filtration, 150mAs, 192x0.6-mm slice collimation) and 65 patients to the standard low-dose protocol (100 kV, 50mAs, 128 × 0.6-mm slice collimation). To assess the image quality, subjective parameters were evaluated using a five-point scale. This scale was applied on overall image quality and contour delineation of critical anatomical structures. RESULTS: All scans were of diagnostic image quality. Bony structures were of good diagnostic image quality in both groups, soft tissues were of sufficient diagnostic image quality in the study group because of a high level of noise. Radiation exposure was very low in both groups, but significantly lower in the study group (CTDIvol 1.2 mGy vs. 4.4 mGy, p < 0.001). CONCLUSIONS: Spectral optimization (tin filtration at 100 kV) allows for visualization of the paranasal sinus with sufficient image quality at a very low radiation exposure. KEY POINTS: • Spectral optimization (tin filtration) is beneficial to low-dose parasinus CT • Tin filtration at 100 kV yields sufficient image quality for pre-operative planning • Diagnostic parasinus CT can be performed with an effective dose <0.05 mSv.

Contrast volume reduction using third generation dual source computed tomography for the evaluation of patients prior to transcatheter aortic valve implantation.

OBJECTIVES: Chronic renal failure is common in patients referred for transcatheter aortic valve implantation (TAVI). CT angiography is recommended and provides crucial information prior to TAVI. We evaluated the feasibility of a reduced contrast volume protocol for pre-procedural CT imaging. METHODS: Forty consecutive patients were examined with prospectively ECG-triggered high-pitch spiral acquisition using a novel third-generation dual-source CT system; 38 ml contrast agent was used. Image quality was graded on a visual scale (1-4). Contrast attenuation was measured at the level of the aortic root and at the iliac bifurcation. RESULTS: Mean patient age was 82 ± 6 years (23 males; 58 %). Mean attenuation/average image quality was 285 ± 60 HU/1.5 at the aortic annulus compared to 289 ± 74 HU/1.8 at the iliac bifurcation (p = 0.77/p = 0.29). Mean estimated effective radiation dose was 2.9 ± 0.3 mSv. A repeat acquisition was necessary in one patient due to image quality. Out of the 35 patients who underwent TAVI, 31 (89 %) patients had no or mild aortic regurgitation. Thirty-two (91 %) patients were discharged successfully. CONCLUSION: Pre-procedural CTA with a total of 38 ml contrast volume is feasible and clinically useful, using third-generation dual-source CT, allowing comprehensive imaging for procedural success. KEY POINTS: • Reduction of contrast agent volume is crucial in patients with chronic renal failure. • Novel third-generation computed tomography helps to reduce contrast agent volume. • Pre-procedural CT allows comprehensive imaging for procedural success before heart valve implantation. • A low-contrast CT protocol is feasible for pre-procedural TAVI planning.

Third-generation dual-source 70-kVp chest CT angiography with advanced iterative reconstruction in young children: image quality and radiation dose reduction.

BACKGROUND: Many technical updates have been made in multi-detector CT. OBJECTIVE: To evaluate image quality and radiation dose of high-pitch second- and third-generation dual-source chest CT angiography and to assess the effects of different levels of advanced modeled iterative reconstruction (ADMIRE) in newborns and children. MATERIALS AND METHODS: Chest CT angiography (70 kVp) was performed in 42 children (age 158 ± 267 days, range 1-1,194 days). We evaluated subjective and objective image quality, and radiation dose with filtered back projection (FBP) and different strength levels of ADMIRE. For comparison were 42 matched controls examined with a second-generation 128-slice dual-source CT-scanner (80 kVp). RESULTS: ADMIRE demonstrated improved objective and subjective image quality (P < .01). Mean signal/noise, contrast/noise and subjective image quality were 11.9, 10.0 and 1.9, respectively, for the 80 kVp mode and 11.2, 10.0 and 1.9 for the 70 kVp mode. With ADMIRE, the corresponding values for the 70 kVp mode were 13.7, 12.1 and 1.4 at strength level 2 and 17.6, 15.6 and 1.2 at strength level 4. Mean CTDIvol, DLP and effective dose were significantly lower with the 70-kVp mode (0.31 mGy, 5.33 mGy*cm, 0.36 mSv) compared to the 80-kVp mode (0.46 mGy, 9.17 mGy*cm, 0.62 mSv; P < .01). CONCLUSION: The third-generation dual-source CT at 70 kVp provided good objective and subjective image quality at lower radiation exposure. ADMIRE improved objective and subjective image quality.

Chronic recurrent multifocal osteomyelitis in association with pyoderma gangraenosum.

BACKGROUND: Chronic recurrent multifocal osteomyelitis (CRMO) is a rare acquired inflammatory skeletal disorder of unknown origin. CRMO was first described by Gideon in 1972 and mainly affects children and young adults of female gender. The CRMO is part of the clinical picture of non-bacterial Osteomyelitis (NBO) and typically presents a relapsing recurring course with both remission and spontaneous exacerbation. CRMO is typically encountered in the limbs and the metaphysis of long bones in particular. Usually the clinical symptoms include painful swellings of the affected regions. This case report describes the rare case of a CRMO of the mandible in association with pyoderma gangraenosum. CASE PRESENTATION: A 14-year old female caucasian patient, residing in the south of Germany, presented in the oncological outpatient clinic of our Department of Paediatrics and Adolescent Medicine in June 2014 complaining of increasing neck pain and progressive swelling at her left cheek ongoing for about 6 weeks. These symptoms had been occurring quarterly for 4 years, but had never been as pronounced. Blood biochemistry showed a moderately elevated CRP (35 mg/l) and a significantly increased blood sedimentation rate (BSR 48/120 mm). The panoramic radiograph, however, revealed a bone alteration in the left mandibular region. Further investigations confirmed the diagnosis of CRMO. CONCLUSION: The present case underlines the fact that rare diseases might occasionally present with even more rare symptoms. These occasions can obviously be considered to present a considerable diagnostic challenge.

Single-cycle induction chemotherapy followed by chemoradiotherapy or surgery in patients with head and neck cancer: what are the best predictors of remission and prognosis?

BACKGROUND: There is controversy over the concept of function and organ preservation by chemotherapy/chemoradiation instead of surgery in locally advanced cancer of the larynx or pharynx. Tumor response to induction chemotherapy (ICT) can help in choosing between conservative and surgical treatment. This study compared 3 methods of assessing response to ICT: endoscopy, computed tomography, and (18) F-FDG-PET/CT. METHODS: Primary response to 1 cycle of ICT with docetaxel plus platinum was assessed by the aforementioned methods in 62 laryngopharyngeal cancer patients. Endoscopic response was the deciding factor for selecting further treatment: surgery for endoscopic nonresponders (<30% tumor response) versus chemoradiotherapy for endoscopic responders. RESULTS: ICT achieved endoscopic response in 48 of 62 patients (77%). Individual relative residual tumor activity of standardized uptake value (resSUV(max)) in (18)F-FDG-PET/CT was a median 0.38 of baseline (0.09-1.71), whereas residual tumor extent in CT (resCT) was 0.75 of baseline (0.32-1.20). Endoscopic responders and nonresponders differed significantly in SUV(max) after ICT (postSUVmax , 6.0 vs 14.5; P < .001), resSUV(max) (0.34 vs 0.81, P < .001), and resCT (0.71 vs 0.87, P = .004), but not in maximum tumor diameter after ICT (14 vs 20 mm, P = .11). resSUV(max) <0.8 and absolute postSUV(max) <10 provided the best discriminatory power for long-term success criteria (tumor-free survival, overall survival). CONCLUSIONS: Metabolic tumor response showed very good correlation with clinical tumor response to ICT. The value of metabolic response detected by (18)F-FDG-PET/CT should be explored in a prospective clinical trial.

Influence of Cardiac MR Imaging on DNA Double-Strand Breaks in Human Blood Lymphocytes.

PURPOSE: To evaluate the ability of magnetic resonance (MR) imaging to induce deoxyribonucleic acid (DNA) damage in patients who underwent cardiac MR imaging in daily routine by using γ-H2AX immunofluorescence microscopy. MATERIALS AND METHODS: This study complies with the Declaration of Helsinki and was performed according to local ethics committee approval. Informed patient consent was obtained. Blood samples from 45 patients (13 women, 32 men; mean age, 50.3 years [age range, 20-89 years]) were obtained before and after contrast agent-enhanced cardiac MR imaging. MR imaging-induced double-strand breaks (DSBs) were quantified in isolated blood lymphocytes by using immunofluorescence microscopy after staining the phosphorylated histone variant γ-H2AX. Twenty-nine patients were examined with a myocarditis protocol (group A), 10 patients with a stress-testing protocol (group B), and six patients with flow measurements and angiography (group C). Paired t test was performed to compare excess foci before and after MR imaging. RESULTS: The mean baseline DSB level before MR imaging and 5 minutes after MR imaging was, respectively, 0.116 DSB per cell ± 0.019 (standard deviation) and 0.117 DSB per cell ± 0.019 (P = .71). There was also no significant difference in DSBs in these subgroups (group A: DSB per cell before and after MR imaging, respectively, 0.114 and 0.114, P = .91; group B: DSB per cell before and after MR imaging, respectively, 0.123 and 0.124, P = .78; group C: DSB per cell before and after MR imaging, respectively, 0.114 and 0.115, P = .36). CONCLUSION: By using γ-H2AX immunofluorescence microscopy, no DNA DSBs were detected after cardiac MR imaging.

'Neuroendocrine' middle ear adenomas: consistent expression of the transcription factor ISL1 further supports their neuroendocrine derivation.

AIMS: Neuroendocrine middle ear adenoma (MEA) is a rare epithelial neoplasm of uncertain histogenesis that frequently shows neuroendocrine features. To date, <120 cases have been reported. The aims of the current study were to describe our experience with neuroendocrine MEA, to assess the frequency of specific neuroendocrine differentiation, and to test these lesions for transcription factors known to be expressed in a variety of other neuroendocrine tumours. METHODS AND RESULTS: We investigated six cases of neuroendocrine MEA, and stained them, for the first time, for the transcription factors CDX2, TTF1, PAX8, and ISL1 (islet-1). The patients were four men and two women (mean age, 39 years; range, 27-53 years). Two of four patients with extended follow-up (4.5-22 years) experienced recurrence at 92 months, and at 9 and 22 years, respectively. One case extending into the external ear coexisted with cholesteatoma. Histological examination showed trabecular, solid, acinar, glandular, cribriform, organoid, nested, diffuse non-cohesive plasmacytoid and pseudoalveolar patterns in varying combinations. Immunohistochemistry showed consistent expression of vimentin (4/4), pancytokeratin (6/6), synaptophysin (6/6), CD56 (4/4), and ISL1 (6/6). A CK7 antibody stained scattered cells in two of five cases. The myoepithelial markers and transcription factors TTF1, CDX2 or PAX8 were not expressed in any of the cases. CONCLUSIONS: Middle ear adenoma is an indolent, locally recurring, but generally non-metastasizing neoplasm with uniform expression of synaptophysin and ISL1, indicating true neuroendocrine differentiation. Because of its highly varied cellular and architectural appearance, MEA should be distinguished from tympanic paraganglioma and a variety of rare benign and malignant lesions at this site.

Reproducibility of aortic annulus measurements by computed tomography.

OBJECTIVES: To evaluate a systematic approach for measurement of aortic annulus dimensions by cardiac computed tomography. METHODS: CT data sets of 64 patients were evaluated. An oblique cross-section aligned with the aortic root was created by systematically identifying the caudal insertion points of the three aortic cusps and sequentially aligning them in a double oblique plane. Aortic annulus dimensions, distances of coronary ostia and a suitable fluoroscopic projection angle were independently determined by two observers. RESULTS: Interobserver intraclass correlation coefficients (ICC) for aortic annulus diameters were excellent (ICC 0.89-0.93). Agreement for prosthesis size selection was excellent (ĸ = 0.86 for mean, ĸ = 0.84 for area-derived and ĸ = 0.91 for circumference-derived diameter). Mean distances of the left/right coronary ostium were 13.4 ± 2.4/14.4 ± 2.8 mm for observer 1 and 13.2 ± 2.7/13.5 ± 3.2 mm for observer 2 (p = 0.30 and p = 0.0001, respectively; ICC 0.76/0.77 for left/right coronary artery). A difference of less than 10° for fluoroscopic projection angle was achieved in 84.3% of patients. CONCLUSIONS: A systematic approach to generate a double oblique imaging plane exactly aligned with the aortic annulus demonstrates high interobserver and intraobserver agreements for derived measurements which are not influenced by aortic root calcification. KEY POINTS: • Systematic approach to generate a double oblique imaging plane for TAVI evaluation. • This method is straightforward and software independent. • An approach with high reproducibility, not influenced by aortic root calcification.

Dose reduction of the female breast in chest CT.

OBJECTIVE: Organ-based tube current modulation has been shown to significantly reduce the radiation dose to the female breast in phantom studies. We sought to assess the proportions of female breast and glandular tissues that are within the range of organ-based tube current modulation in different age groups and whether these proportions could be optimized by clothing. The secondary objective of our study was to determine whether metal parts of brassieres cause artifacts that impair the diagnostic value. SUBJECTS AND METHODS: Five hundred seventy-eight female patients undergoing chest CT were included in this study. Two hundred nine patients were prospectively examined wearing a brassiere (group A), and the control patients (group B; n = 369) were scanned according to our previous standard without wearing a brassiere during CT. The two groups were subdivided according to cup size (A-E). For CT data acquisition, an angle-dependent tube current modulation, which reduces the tube current for anterior tube position to minimize direct exposure to anteriorly located organs, was used. The proportion of breast tissue and glandular tissue located within and outside the region of tube current reduction was assessed. RESULTS: The results showed that 60.4% of total breast tissue and 67.1% of glandular tissue was inside the region of tube current reduction in group B; the proportions were significantly improved, to an average of 91.3% and 96%, respectively, in group A. Diagnostically relevant artifacts were introduced in none of the patients. Patients' age correlated with this effect, with higher rates of improvement in the older patient group. Angle-dependent tube current modulation was most effective in patients with cup size A while wearing a brassiere. In this group, 97.5% of breast tissue and 98.1% of glandular tissue was inside the region of tube current reduction. Women with a cup size of E had the largest effect of wearing a brassiere, increasing the rate of breast tissue that was affected by angle-dependent tube current modulation from 30.0% to 83.3% and that of glandular tissue from 31.8% to 90.0%. CONCLUSION: We show that wearing a brassiere increases the percentage of breast tissue within the region of reduced tube current and, therefore, improves the performance of angle-dependent tube current modulation technique.

Automated tube voltage adaptation in head and neck computed tomography between 120 and 100 kV: effects on image quality and radiation dose.

INTRODUCTION: Low tube voltage allows for computed tomography (CT) imaging with increased iodine contrast at reduced radiation dose. We sought to evaluate the image quality and potential dose reduction using a combination of attenuation based tube current modulation (TCM) and automated tube voltage adaptation (TVA) between 100 and 120 kV in CT of the head and neck. METHODS: One hundred thirty consecutive patients with indication for head and neck CT were examined with a 128-slice system capable of TCM and TVA. Reference protocol was set at 120 kV. Tube voltage was reduced to 100 kV whenever proposed by automated analysis of the localizer. An additional small scan aligned to the jaw was performed at a fixed 120 kV setting. Image quality was assessed by two radiologists on a standardized Likert-scale and measurements of signal- (SNR) and contrast-to-noise ratio (CNR). Radiation dose was assessed as CTDIvol. RESULTS: Diagnostic image quality was excellent in both groups and did not differ significantly (p = 0.34). Image noise in the 100 kV data was increased and SNR decreased (17.8/9.6) in the jugular veins and the sternocleidomastoid muscle when compared to 120 kV (SNR 24.4/10.3), but not in fatty tissue and air. However, CNR did not differ statistically significant between 100 (23.5/14.4/9.4) and 120 kV data (24.2/15.3/8.6) while radiation dose was decreased by 7-8%. CONCLUSIONS: TVA between 100 and 120 kV in combination with TCM led to a radiation dose reduction compared to TCM alone, while keeping CNR constant though maintaining diagnostic image quality.

Clinical relevance and prognostic value of radiographic findings in Zenker's diverticulum.

The aim of this study was to evaluate the clinical relevance and prognostic value of preoperative and postoperative oesophagography in patients with Zenker's diverticulum. The medical records of 155 patients who underwent surgical treatment (with an endoscopic or transcervical approach) for Zenker's diverticulum between 1992 and 2010 in a tertiary referral centre were retrospectively evaluated. The size of the diverticula on oesophagography, recognizable muscular septum, and protection of the diverticulum were assessed relative to the surgical procedures performed. The incidence of diverticular remnants on postoperative oesophagography was also assessed relative to the surgical procedure. It was investigated whether the detection of a residual pharyngeal pouch and filling of it with contrast medium were related to the patients' immediate postoperative symptoms and the development of symptomatic recurrence. Larger diverticula (Brombart III-IV) were manageable significantly more often with endoscopic procedures (P = 0.007). Residual diverticulum and filling with contrast medium were strongly associated with prolonged dysphagia immediately postoperatively (P = 0.005 and P = 0.009, respectively). However, these parameters failed to correlate significantly with a symptomatic recurrence. Preoperative oesophagography proved to be extremely important for surgical planning, with the surgeon's personal preference seeming to be the driving indicator in many cases. Postoperative oesophagography is only useful for excluding postoperative complications in the immediate postoperative phase and did not have a prognostic value as to a recurrence of the disease.

Comparative study of image quality and radiation dose of cone beam and low-dose multislice computed tomography--an in-vitro investigation.

OBJECTIVES: The aim of this study was to evaluate the image quality and dose exposition of different cone-beam computed tomography (CBCT) and low-dose multislice spiral CT (MSCT) scanners. MATERIALS AND METHODS: A human cadaver head was examined with three MSCT and five CBCT scanners. The radiation dose was measured using an Alderson RANDO phantom. Standard protocols were used to obtain the CBCT data. For the MSCT devices, the tube voltage and tube current were modified to obtain acceptable image quality while keeping the radiation dose as low as possible. The image quality of MSCT and CBCT devices was determined by examining the enamel-dentin and dentin-pulp interface and the periodontal ligament space of 22 teeth. RESULTS: Inter- and intra-observer agreement was found for the different groups of raters. CBCT systems were rated superior to MSCT devices in terms of image quality for all dental structures. The differences in image quality among the studied CBCT and MSCT scanner groups did not turn out to be significant but were significant between CBCT and MSCT devices. The organ dose varied considerably between the different CBCT and MSCT devices. The differences concerning the organ dose were notably pronounced in the area of the eye lens. CONCLUSIONS: The tested devices exhibited significant differences with respect to the organ dose. The variance was particularly pronounced in the CBCT devices. With a dose exposition equal or lower than the CBCT, the image quality in the MSCT devices was judged to be significantly worse.