Achieving a Successful Scale-Down Model and Optimized Economics through Parvovirus Filter Validation using Purified TrueSpikeTM Viruses.

UNLABELLED: This article describes a four virus panel validation of EMD Millipore's (Bedford, MA) small virus-retentive filter, Viresolve® Pro, using TrueSpike(TM) viruses for a Biogen Idec process intermediate. The study was performed at Charles River Labs in King of Prussia, PA. Greater than 900 L/m(2) filter throughput was achieved with the approximately 8 g/L monoclonal antibody feed. No viruses were detected in any filtrate samples. All virus log reduction values were between ≥3.66 and ≥5.60. The use of TrueSpike(TM) at Charles River Labs allowed Biogen Idec to achieve a more representative scaled-down model and potentially reduce the cost of its virus filtration step and the overall cost of goods. The body of data presented here is an example of the benefits of following the guidance from the PDA Technical Report 47, The Preparation of Virus Spikes Used for Viral Clearance Studies. LAY ABSTRACT: The safety of biopharmaceuticals is assured through the use of multiple steps in the purification process that are capable of virus clearance, including filtration with virus-retentive filters. The amount of virus present at the downstream stages in the process is expected to be and is typically low. The viral clearance capability of the filtration step is assessed in a validation study. The study utilizes a small version of the larger manufacturing size filter, and a large, known amount of virus is added to the feed prior to filtration. Viral assay before and after filtration allows the virus log reduction value to be quantified. The representativeness of the small-scale model is supported by comparing large-scale filter performance to small-scale filter performance. The large-scale and small-scale filtration runs are performed using the same operating conditions. If the filter performance at both scales is comparable, it supports the applicability of the virus log reduction value obtained with the small-scale filter to the large-scale manufacturing process. However, the virus preparation used to spike the feed material often contains impurities that contribute adversely to virus filter performance in the small-scale model. The added impurities from the virus spike, which are not present at manufacturing scale, compromise the scale-down model and put into question the direct applicability of the virus clearance results. Another consequence of decreased filter performance due to virus spike impurities is the unnecessary over-sizing of the manufacturing system to match the low filter capacity observed in the scale-down model. This article describes how improvements in mammalian virus spike purity ensure the validity of the log reduction value obtained with the scale-down model and support economically optimized filter usage.

Comparison of accuracy and reproducibility of casts made by digital and conventional methods.

STATEMENT OF PROBLEM: Little peer-reviewed information is available regarding the accuracy and reproducibility of digitally fabricated casts compared to conventional nondigital methods. PURPOSE: The purpose of this in vitro study was to compare the accuracy and reproducibility of a digital impression and cast fabrication with a conventional impression and cast fabrication. MATERIAL AND METHODS: Conventional impressions were made via a 1-step single viscosity technique with vinyl siloxanether material of a typodont master model, and conventional casts were cast from dental stone. Digital impressions were obtained with a digital scanner, and digital stereolithographic models were printed. The typodont and fabricated casts were digitized with a structured light scanner and saved in surface tessellation language (STL) format. All STL records were superimposed via a best-fit method. The digital impression and cast fabrication method was compared with the conventional impression and cast fabrication method for discrepancy, accuracy, and reproducibility. The Levene test was used to determine equality of variances, and a 1-way ANOVA was conducted to assess the overall statistical significance of differences among the groups (n=5, α=.05). RESULTS: No significant statistical difference was found between the digital cast and conventional casts in the internal area or finish line area (P>.05). In addition, there was no statistically significant difference between these 2 techniques for a fixed dental prosthesis or single crown (P>.05). However, statistically significant differences were observed for overall areas of the casts in terms of accuracy (P<.01) and reproducibility (P<.001). Digital impression and cast fabrication were less accurate and reproducible than conventional impression and cast fabrication methods. CONCLUSIONS: No statistically significant difference was found between the digital cast and conventional cast groups in the internal and finish line areas. However, in terms of the reproducibility and accuracy of the entire cast area, the conventional cast was significantly better than the digital cast.

Morphologic outcome of bimaxillary surgery-An anthropometric appraisal

OBJECTIVES: To adequately perform orthognathic surgery procedures, it is from basic interest to understand the morphologic changes caused by orthognathic surgery. Anthropometric analyses of standardized frontal view and profile photographs could help to investigate and understand such changes. Study DESIGN: We present a pre- to postoperative evaluation of orthognathic surgery results based on anthropometric indices described by Farkas and cephalometric measurements. 30 Class III patients undergoing maxillary advancement by Le Fort I Osteotomy and mandibular setback by bilateral sagittal split osteotomy were evaluated. Preoperative as well as three and nine months postoperative lateral cephalograms as well as standardized frontalview and profile photographs were taken. On the photographs 21 anthropometric indices given by Farkas were evaluated. In cephalograms SNA and SNB angle as well as Wits appraisal were investigated. RESULTS: The investigated anthropometric indices showed a significant increase of the vertical height of the upperlip without changing the relation of the upper vermilion to the cutaneous upper lip. The lower vermilion height increased relatively to the cutaneous lower lip without vertical changes in the lower lip. Due to maxillary advancement the upper face height increased meanwhile the lower face height decreased due to mandibular setback. SNA and SNB angle and Wits appraisal showed typical changes related to surgery

Quality of postoperative pain management after midfacial fracture repair--an outcome-oriented study.

OBJECTIVES: There is a lack of literature regarding the procedure-specific quality of acute postoperative pain management after midfacial fracture repair. The purpose of the presented prospective clinical study was to evaluate postoperative pain management after surgical repair of midfacial fractures. MATERIALS AND METHODS: Eighty-five adults were evaluated on the first postoperative day following midfacial repair using the questionnaire of the Quality Improvement in Postoperative Pain Management (QUIPS) project. The main outcome measures were patients' characteristics and clinical- and patient-reported outcome parameters. RESULTS: Overall, pain on the first postoperative day was moderate. A significant correlation between process and outcome parameters could be shown. Duration of surgery above the calculated median was significantly associated with higher maximum pain intensity (p = 0.017). Patients requiring opioids in the recovery room presented significantly higher pain on activity (p = 0.029) and maximum pain (p = 0.035). Sleeping impairment (p = 0.001) and mood disturbance (p = 0.008) were significantly more prevalent in patients undergoing repair of a centrolateral midfacial fracture. CONCLUSIONS: QUIPS is a simple and qualified tool to evaluate the procedure specific quality of acute postoperative pain management. Pain on the first postoperative day following midfacial fracture repair seems overall to be moderate. Nearly a third of the patients showed inadequate postoperative pain management. To prevent inadequate postoperative pain management, it is necessary to establish a continued procedure-specific outcome measurement.

Morphologic outcome of bimaxillary surgery--an anthropometric appraisal.

OBJECTIVES: To adequately perform orthognathic surgery procedures, it is from basic interest to understand the morphologic changes caused by orthognathic surgery. Anthropometric analyses of standardized frontal view and profile photographs could help to investigate and understand such changes. STUDY DESIGN: We present a pre- to postoperative evaluation of orthognathic surgery results based on anthropometric indices described by Farkas and cephalometric measurements. 30 Class III patients undergoing maxillary advancement by Le Fort I Osteotomy and mandibular setback by bilateral sagittal split osteotomy were evaluated. Preoperative as well as three and nine months postoperative lateral cephalograms as well as standardized frontal view and profile photographs were taken. On the photographs 21 anthropometric indices given by Farkas were evaluated. In cephalograms SNA and SNB angle as well as Wits appraisal were investigated. RESULTS: The investigated anthropometric indices showed a significant increase of the vertical height of the upper lip without changing the relation of the upper vermilion to the cutaneous upper lip. The lower vermilion height increased relatively to the cutaneous lower lip without vertical changes in the lower lip. Due to maxillary advancement the upper face height increased meanwhile the lower face height decreased due to mandibular setback. SNA and SNB angle and Wits appraisal showed typical changes related to surgery. CONCLUSIONS: The investigated photo-assisted anthropometric measurements presented reproducible results related to bimaxillary surgery.

Impact of digital impression techniques on the adaption of ceramic partial crowns in vitro.

OBJECTIVES: To investigate the effects, digital impression procedures can have on the three-dimensional fit of ceramic partial crowns in vitro. METHODS: An acrylic model of a mandibular first molar was prepared to receive a partial coverage all-ceramic crown (mesio-occlusal-distal inlay preparation with reduction of all cusps and rounded shoulder finish line of buccal wall). Digital impressions were taken using iTero (ITE), cara TRIOS (TRI), CEREC AC with Bluecam (CBC), and Lava COS (COS) systems, before restorations were designed and machined from lithium disilicate blanks. Both the preparation and the restorations were digitised using an optical reference-scanner. Data were entered into quality inspection software, which superimposed the records (best-fit-algorithm), calculated fit-discrepancies for every pixel, and colour-coded the results to aid visualisation. Furthermore, mean quadratic deviations (RMS) were computed and analysed statistically with a one-way ANOVA. Scheffé's procedure was applied for multiple comparisons (n=5, α=0.05). RESULTS: Mean marginal (internal) discrepancies were: ITE 90 (92) µm, TRI 128 (106) µm, CBC 146 (84) µm, and COS 109 (93) µm. Differences among impression systems were statistically significant at p<0.001 (p=0.039). Qualitatively, partial crowns were undersized especially around cusp tips or the occluso-approximal isthmus. By contrast, potential high-spots could be detected along the preparation finishline and at central occlusal boxes. CONCLUSIONS: Marginal and internal fit of milled lithium disilicate partial crowns depended on the employed digital impression technique. CLINICAL SIGNIFICANCE: The investigated digital impression procedures demonstrated significant fit discrepancies. However, all fabricated restorations showed acceptable marginal and internal gap sizes, when considering clinically relevant thresholds reported in the literature.

Perioral aging--an anthropometric appraisal.

To adequately perform perioral rejuvenation procedures, it is necessary to understand the morphologic changes caused by facial aging. Anthropometric analyses of standardized frontal view and profile photographs could help to investigate such changes. Photographs of 346 male individuals were evaluated using 12 anthropometric indices. Data from two groups of health subjects, the first exhibiting a mean age of nearly 20 and the second of nearly 60 years, were compared. To evaluate the influence of combined nicotine and alcohol abuse, the data of the second group were compared to a third group exhibiting a similar mean age who were known alcohol and nicotine abusers. Comparison of the first to the second group showed significant decrease of the vertical height of upper and lower vermilion and relative enlargement of the cutaneous part of upper and lower lips. This effect was stronger in the upper vermilion and medial upper lips. The sagging of the upper lips led to the appearance of an increased mouth width. In the third group the effect of sagging of the upper lips, and especially its medial portion was significantly higher compared to the second group. The photo-assisted anthropometric measurements investigated gave reproducible results related to perioral aging.

Cheek rotation flap reconstruction--an anthropometric appraisal of surgical outcomes.

OBJECTIVES: Cheek rotation flaps are an established surgical procedure for coverage of facial skin defects especially of the cheek and infraorbital region. A comparison of pre- and postoperative anthropometric measurements may help to objectify intraoperative estimations with regards to postoperative appearance. MATERIALS AND METHODS: We present an evaluation of 31 patients undergoing periorbital reconstruction by a cheek rotation flap on standardized photographs based on reference anthropometric data. Analysis included intercanthal, binocular and eye fissure width, eye fissure, lid sulcus and upper lid height, upper and lower iris coverage, position of cornea to palpebra inferior, scleral show, ectropion, and canthal tilt. Furthermore, it was clearly differentiated whether the defect to cover included eyelid skin or not. RESULTS: Ectropion showed a significant association to surgery (p = 0.03) and time (p = 0.03). If the defect to cover included lower eyelid skin, lower iris coverage values decreased significantly (p = 0.02), meanwhile the rate of scleral show increased significantly (p < 0.01), indicating pre- to postoperative lower eyelid retraction. CONCLUSIONS: In all patients analyzed, indices were reproducible and reliable. An association between surgery and ectropion was detectable. Whenever lower eyelid skin is involved in the defect to be covered, the significantly decreased lower iris coverage and increased rate of scleral show indicate an increased risk of lower lid retraction. CLINICAL RELEVANCE: Whenever eyelid skin is involved in a defect to be covered by a cheek rotation flap, there is an increased risk of postoperative lower lid distortion. Special care has to be taken to perform techniques preventing lower lid retraction.

Effect of CNC-milling on the marginal and internal fit of dental ceramics: a pilot study.

OBJECTIVES: Machined restorations have been investigated for their preciseness before, while detailed information on the milling-step itself are lacking. Therefore, the aim of this laboratory study was to quantify the effect of a novel milling-procedure on the marginal and internal fit of ceramic restorations. METHODS: An acrylic model of a lower left first molar was prepared to receive a ceramic partial crown and was duplicated by one step dual viscosity impressions. Gypsum casts were formed and laser-scanned to realize virtual datasets, before restorations were designed, exported (PRE) and machined from lithium disilicate blanks. Crowns were digitized by a structure-light-scanner to obtain post-milling-data (POST). PRE and POST were virtually superimposed on the reference tooth and subjected to computer-aided-inspection. Visual fit-discrepancies were displayed with colors, while root mean square deviations (RMSD) and degrees of similarity (DS) were computed and analysed by t-tests for paired samples (n=5, α=0.05). RESULTS: The milling procedure resulted in a small increase of the marginal and internal fit discrepancies (RMSD mean: 3µm and 6µm, respectively). RMSD differences were not statistically significant (p=0.495 and p=0.160 for marginal and internal fit, respectively). These results were supported by the DS data. SIGNIFICANCE: The products of digital dental workflows are prone to imprecisions. However, the present findings suggest that differences between computer-aided designed and actually milled restorations are small, especially when compared to typical fit discrepancies observed clinically. Imprecisions introduced by digital design or production processes are small.

Soft tissue outcome after mandibular advancement--an anthropometric evaluation of 171 consecutive patients.

OBJECTIVES: There is an ongoing discussion in the literature about preoperative planning and postoperative evaluation of orthognathic surgery and its impact on facial appearance and aesthetics. MATERIALS AND METHODS: We present an anthropometric and cephalometric evaluation of orthognathic surgery results based on reference anthropometric data. In 171 Class II patients, mandibular advancement by bilateral sagittal split osteotomy was performed. Preoperative as well as 3 and 9 months postoperative standardized frontal view and profile photographs and lateral cephalograms were evaluated in a standardized manner by use of 21 anthropometric indices. In cephalograms, SNA and SNB angle as well as Wits appraisal were investigated. Results of anthropometric and cephalometric measurements were correlated. RESULTS: Lower vermilion contour, vermilion and cutaneous total lower lip height, nose-lower face height, nose-face height, upper face-face height, upper lip- and chin-mandible height index showed significant pre- to postoperative changes as well as SNB angle and Wits appraisal. Furthermore, medial-lateral cutaneous upper lip height, vermilion and cutaneous total lower lip height and philtrum-mouth width index presented significant correlations to cephalometric measurements. CONCLUSIONS: The investigated anthropometric indices and cephalometric measurements presented reproducible results related to surgery. The correlation of cephalometric to anthropometric measurements has been proven useful for preoperative planning and postoperative evaluation of orthognathic surgery patients. CLINICAL RELEVANCE: The presented anthropometric measurements and their observed correlation to cephalometric measurements could lead to a better prediction and optimized planning of the soft tissue result in orthognathic surgery patients and thereby improve the aesthetic outcome.

Transconjunctival versus subciliary approach for orbital fracture repair--an anthropometric evaluation of 221 cases.

OBJECTIVES: In the literature, there is an ongoing discussion about the influence of orbital fractures and the surgical approach on the rate of eyelid deformities of the lower eyelid. MATERIALS AND METHODS: We present an evaluation of a series of 221 patients 9 months after zygomaticomaxillary complex fracture repair that underwent implant removal. Reference anthropometric data were measured on standardized pre- and postoperative photographs. Analysis included eye fissure width and height, lid sulcus and upper lid height, upper and lower iris coverage, position of cornea to palpebra inferior, canthal tilt, scleral show, ectropion, and entropion. Both operated and contralateral eyelids were evaluated as well as whether a transconjunctival or a subciliary approach was performed. RESULTS: Time, surgery, and surgical approach presented significant effects on eye fissure index and lower iris coverage. Scleral show was significantly influenced by the surgical procedure itself as well as by the type of incision. The rate of ectropion increased significantly pre- to postoperative. CONCLUSIONS: The subciliary approach included the highest risk of lower lid retraction. The low pre- to postoperative increase of scleral show and ectropion compared to recent studies gives us an idea about the influence of the underlying trauma on the rate of lower lid retraction. The standardized measurements described are accurately and objective to evaluate postoperative results. CLINICAL RELEVANCE: The transconjunctival approach is preferable in orbital fracture repair.

The zygomaticomaxillary complex fracture - an anthropometric appraisal of surgical outcomes.

Before undergoing repair of zygomaticomaxillary complex fractures, most patients are worried about their postoperative appearance. Furthermore, there is an ongoing discussion about the selection of the surgical approach to the inferior orbita and resulting eyelid deformities. We present a photo-assisted postoperative evaluation of zygomaticomaxillary complex fracture repair based on reference anthropometric data. Two hundred and twenty-one patients underwent zygomaticomaxillary complex fracture repair. An analysis of standardized postoperative photographs included measurements of eye fissure width and height, lid sulcus height, upper lid height, upper and lower coverage, position of cornea to palpebra inferior, canthal tilt, scleral show, ectropion and entropion. It was clearly distinguished between operated and contralateral eyelid, and whether a transconjunctival or a subciliary approach was performed. Surgery per se significantly influenced eyelid deformities as measured by its impact on eye fissure index, lower iris coverage and rate of scleral show and ectropion. The surgical approach selected significantly affected eye fissure index, lower iris coverage and rate of scleral show, indicating distortion of the lower eyelid. Investigations regarding orbital fractures should clearly differentiate the type of fracture. The subciliary approach included the highest risk of postoperative lower eyelid deformity in zygomaticomaxillary complex fracture repair. The standardized measurements described here are accurate and objective to evaluate postoperative results.

Three-dimensional fit of lithium disilicate partial crowns in vitro.

OBJECTIVES: A novel three-dimensional scanning technique was used to investigate the effects a one-step and a two-step impression methods can have on the three-dimensional fit of ceramic partial crowns. METHODS: An acrylic model of a mandibular first molar was prepared to receive a partial coverage all-ceramic crown (mesio-occlusal-distal inlay preparation with reduction of all cusps and rounded shoulder finish line of buccal wall). Type IV plaster replicates were cast based on one-step single viscosity (OS/SV), one-step dual viscosity (OS/DV), and two-step dual viscosity (TS/DV) impressions. Five partial crowns were fabricated per impression method using hot-pressed lithium disilicate ceramics. Then, preparation and restorations were digitized using a non-contact, white-light scanner featuring self-calibrating optics (overall measurement uncertainty of <5µm). Data were entered into quality inspection software which superimposed the records (best-fit-algorithm), calculated fit-discrepancies for every pixel, and colour-coded the results to aid visualization. Furthermore, mean quadratic deviations (RMS) were computed and analyzed statistically with a 1-way ANOVA. Scheffé's procedure was applied for multiple comparisons (α=0.05). RESULTS: Mean RMS-values for marginal (internal) surfaces were: OS/SV 70 (20)µm, OS/DV 78 (34)µm, and TS/DV 107 (52)µm. Differences among impression techniques were statistically significant at p=0.006 (0.001). Qualitatively, occlusal ridges and preparation finish lines were over contoured, whereas inner occlusal boxes and the proximal-occlusal isthmus were under contoured. CONCLUSIONS: OS/SV and OS/DV impressions resulted in statistically significantly smaller marginal and internal discrepancies than the two-step technique. CLINICAL SIGNIFICANCE: Marginal and internal fit of hot-pressed lithium disilicate partial crowns depended on the employed impression technique. One-step impressions are preferred over two-step techniques in many day-to-day clinical situations, especially for the fabrication of partial coverage crown restorations.

Outcomes analysis of eyelid deformities using photograph-assisted standardized anthropometry in 311 patients after orbital fracture treatment.

BACKGROUND: Before undergoing repair of orbital fractures, most patients are worried about their postoperative appearance. Furthermore, there is an ongoing discussion in the literature about the influence of trauma and surgical approach to the inferior orbita on eyelid deformities. METHODS: In this retrospective comparative study, we present an evaluation of a series of 311 postoperative results of orbital fractures on standardized photographs based on reference anthropometric data. Analysis included eye fissure width and height, lid sulcus height, upper lid height, upper and lower iris coverage, position of cornea to inferior palpebra, canthal tilt, scleral show, ectropion, and entropion. It was clearly differentiated between operated and contralateral eyelid type of fracture of the midface and whether a transconjunctival or a subciliary approach was used. RESULTS: Surgery and the chosen approach presented significant effects on eye fissure index, lower iris coverage, scleral show, and ectropion. Different types of fractures affecting the orbita showed no influence on the investigated values. CONCLUSION: Not surprisingly, an association between surgery and lower lid retraction was found. The underlying osseous trauma did not show a significant influence on the presented measurements. Subciliary approaches increased the risk of lower lid retraction. The standard measurements described here are accurate and objective to evaluate postoperative results. LEVEL OF EVIDENCE: Prognostic/epidemiologic study, level III.

Qualitative and quantitative three-dimensional accuracy of a single tooth captured by elastomeric impression materials: an in vitro study.

STATEMENT OF PROBLEM: The accuracy of impressions has been described in 1 or 2 dimensions, whereas it is most desirable to evaluate the accuracy of impressions spatially, in 3 dimensions. PURPOSE: The purpose of this study was to demonstrate the accuracy and reproducibility of a 3-dimensional (3-D) approach to assessing impression preciseness and to quantitatively comparing the occlusal correctness of gypsum dies made with different impression materials. MATERIAL AND METHODS: By using an aluminum replica of a maxillary molar, single-step dual viscosity impressions were made with 1 polyether/vinyl polysiloxane hybrid material (Identium), 1 vinyl polysiloxane (Panasil), and 1 polyether (Impregum) (n=5). Corresponding dies were made of Type IV gypsum and were optically digitized and aligned to the virtual reference of the aluminum tooth. Accuracy was analyzed by computing mean quadratic deviations between the virtual reference and the gypsum dies, while deviations of the dies among one another determined the reproducibility of the method. The virtual reference was adapted to create 15 occlusal contact points. The percentage of contact points deviating within a ±10 µm tolerance limit (PDP(10) = Percentage of Deviating Points within ±10 µm Tolerance) was set as the index for assessing occlusal accuracy. Visual results for the difference from the reference tooth were displayed with colors, whereas mean deviation values as well as mean PDP(10) differences were analyzed with a 1-way ANOVA and Scheffé post hoc comparisons (α=.05). RESULTS: Objective characterization of accuracy showed smooth axial surfaces to be undersized, whereas occlusal surfaces were accurate or enlarged when compared to the original tooth. The accuracy of the gypsum replicas ranged between 3 and 6 µm, while reproducibility results varied from 2 to 4 µm. Mean (SD) PDP(10)-values were: Panasil 91% (±11), Identium 77% (±4) and Impregum 29% (±3). One-way ANOVA detected significant differences among the subjected impression materials (P<.001). CONCLUSIONS: The accuracy and reproducibility of impressions were determined by 3-D analysis. Results were presented as color images and the newly developed PDP(10)-index was successfully used to quantify spatial dimensions for complex occlusal anatomy. Impression materials with high PDP(10)-values were shown to reproduce occlusal dimensions the most accurately.

Marginal and internal fit of pressed lithium disilicate partial crowns in vitro: a three-dimensional analysis of accuracy and reproducibility.

OBJECTIVES: The objective of this in vitro study was to visualize and to quantify the marginal and internal fit of heat-pressed ceramic restorations by a novel three-dimensional procedure. Accuracy and reproducibility of the employed measuring method were determined. METHODS: An acrylic model of a lower left first molar was prepared to receive a partial crown and duplicated by single step dual viscosity impressions. Corresponding working casts were formed from Type IV die stone and indirect restorations were fabricated from heat-pressable lithium disilicate ceramics (IPS e.max Press, Ivoclar Vivadent AG, Schaan, Liechtenstein). The acrylic tooth model and the ceramic partial crowns were digitized by a structure light scanner with a measurement-uncertainty of 4 µm and subjected to computer-aided quality inspection. Visual discrepancies in marginal and internal fit were displayed with colors. For quantitative analysis, mean quadratic deviations (RMS) were computed and analyzed by Student's t-test (n=5, α=0.05). RESULTS: Mean RMS-values for accuracy (reproducibility) ranged from 34 (14) µm for internal areas to 78 (23) µm for marginal surfaces. Differences in accuracy (p=0.003) and reproducibility (p<0.001) were statistically significant. In general, areas with sharp internal line angles such as occlusal ridges and the preparation finish line exhibited oversized dimensions, whereas areas with rounded and soft internal line angles were undersized. SIGNIFICANCE: The viability of a computer-aided and three-dimensional approach for assessing marginal and internal fit of indirect restorations was demonstrated. Thereby, the obtained results track complex form changes as they occur during laboratory processing.

Systematic comparison of sporadic and syndromic pancreatic islet cell tumors.

Pancreatic islet cell tumors (ICTs) occur as sporadic neoplasias or as a manifestation of multiple endocrine neoplasia type 1 (MEN1) and von Hippel-Lindau disease (VHL). Molecular classification of ICTs is mandatory for timely diagnosis and surveillance. Systematic comparison of VHL-ICTs and sporadic ICTs has been lacking. Our registry-based approaches used the German NET-Registry with 259 patients with neuroendocrine tumors (NETs), who were primarily diagnosed with NETs, and the German VHL-Registry with 485 molecular genetically confirmed patients who had undergone magnetic resonance imaging or computed tomography of the abdomen. All patients provided blood DNA for testing of the MEN1 and VHL genes for intragenic mutations and large deletions. In the NET-Registry, 9/101 patients (8.9%) with ICTs had germline mutations, 8 in MEN1 and 1 in VHL. In the VHL-Registry, prevalence of NETs was 52/487 (10.6%), and all were ICTs. Interestingly, of those with VHL p.R167W, 47% developed ICTs, compared to 2% of those with p.Y98H. In total, there were 92 truly sporadic, i.e. mutation-negative ICT patients. Comparing these with the 53 VHL-ICT patients, the statistically significant differences were predominance of female gender (P=0.01), multifocal ICTs (P=0.0029), and lower malignancy rate (P<0.001) in VHL-ICTs compared to sporadic cases. VHL was prevalent in <0.5% of NETs, while NETs occur in ∼10% of VHL, virtually exclusively as ICTs, which are rarely the first presentation. Patients with NETs should not be subjected to genetic testing of the VHL gene, unless they have multifocal ICTs, other VHL-associated tumors, and/or a family history for VHL.

Continuously moving table MRI with sliding multislice for rectal cancer staging: image quality and lesion detection.

PURPOSE: To determine image quality and lesion detection of sliding multislice (SMS), a recently developed moving table MRI technique, in patients with rectal cancer. MATERIALS AND METHODS: Twenty-seven paired SMS (Avanto, Siemens Medical Solutions) and MDCT (Sensation 64, Siemens Medical Solutions) examinations of abdomen and pelvis were performed in patients with rectal cancer and compared for detection of liver, lymph node and bone metastases by two independent observers. A contrast-enhanced, fat saturated 2D gradient echo sequence (TE, 2.0 ms; TR, 102 ms; slice, 5 mm) was acquired with SMS and a standard contrast-enhanced protocol (100 ml @ 2.5 ml/s; slice, 5 mm) was used for abdominal MDCT. Standard of reference consisted of a consensus evaluation of SMS, MDCT, and all available follow-up examinations after a period of 6 months. Artifact burden and image quality of SMS was assessed in comparison to stationary gradient echo sequences obtained in an age-matched group of 27 patients. RESULTS: Whereas SMS achieved a mean quality score of 3.65 (scale, 0-4) for the liver, representing very good diagnostic properties, strong breathing artifacts in the intestinal region were observed in 19 cases by both observers. The retroperitoneum still achieved a mean quality score of 3.52, although breathing artifacts were noted in 12 and 15 cases (observers 1 and 2, respectively). The sensitivities of SMS to detect hepatic metastases were 91.2% and 94.1% for both observers, respectively, compared to 98.5%/98.5% for MDCT. The sensitivities for lymph node metastases were 87.5%/81.3% for SMS compared to 78.1%/81.3% for MDCT. The sensitivities for bone metastases were 91.7%/100% for SMS compared to 8.3%/16.7% for MDCT. CONCLUSION: With slightly reduced image quality in the intestinal region, SMS exhibits equal detection of lymph node and liver metastases compared to MDCT. SMS MRI proved to be superior to MDCT in detection of bone metastases.

Prospective ECG-triggered CT angiography of the thoracic aorta in patients with atrial fibrillation or accelerated heart rates: feasibility and image quality.

OBJECTIVE: The objective of our study was to prospectively investigate the feasibility and image quality of and to calculate the radiation dose estimates for CT angiography (CTA) of the thoracic aorta in patients with atrial fibrillation or accelerated heart rates using prospective ECG-triggered sequential dual-source data acquisition in end-systole. CONCLUSION: Prospective ECG-gated sequential dual-source CTA of the thoracic aorta is feasible despite heart rates>80 beats per minute or atrial fibrillation, making motion-free imaging of the thoracic aorta possible at a considerably low radiation dose.

Posttraumatic edema of the lower extremities: evaluation of the lymphatic vessels with magnetic resonance lymphangiography.

OBJECTIVE: To assess for the first time the morphology of the lymphatic system in patients with posttraumatic edema of the lower extremities by magnetic resonance (MR) imaging using the interstitial lymphangiography technique MATERIALS AND METHODS: Six patients with posttraumatic edema in eight of their 12 lower extremities were examined by MR lymphangiography. Eighteen mL of gadoteridol and one mL of mepivacainhydrochloride 1% were subdivided into 10 portions and injected intracutaneously. MR imaging was performed with a 1.5-T system equipped with high-performance gradients. For MR lymphangiography, a 3D-spoiled gradient-echo sequence was used. RESULTS: In five of the eight (63%) traumatized lower extremities, enlarged lymphatic vessels were detected, with the largest diameter measuring 5 mm. Additionally, a fast lymphatic outflow was observed in seven of the eight (88%) traumatized legs with enhancement of the inguinal lymph nodes already in the first image acquisition 15 minutes after contrast material injection. In two of the eight (25%) traumatized lower extremities, an extensive network of collateral lymphatic vessels was detected at the level of the calf. In both extremities, lymphatic collateralization involved not only the epifascial but also the subfascial lymphatic system. In one patient, who sustained a trauma of the left lower leg with tibial fracture, a small aneurysmatic widening of 7 mm could be detected at the middle level of the calf. CONCLUSION: MR lymphangiography is a safe and accurate minimal-invasive imaging modality for the evaluation of the lymphatic circulation in patients with posttraumatic edema of the lower extremities. If the extent of lymphatic damage is unclear at the initial clinical examination or requires a better definition for optimal therapeutic planning, MR lymphangiography is able to identify the anatomic and physiological derangements and to establish an objective baseline.