Comparison of the lower uterine segment in pregnant women with and without previous cesarean section in 3 T MRI.

BACKGROUND: Prenatal risk stratification of women with previous cesarean section (CS) by ultrasound thickness measurement of the lower uterine segment (LUS) is challenging. There is a wide range of proposed cutoff values and a valuable algorithm for selection before birth is not available. Using 3 T magnetic resonance imaging (MRI), we aimed to identify possible shortcomings of the current protocols used for birth selection after CS. Therefore, we evaluated anatomic and morphologic differences of the LUS and its thickness in patients with CS and those without. Possible impact factors on LUS thickness were studied. METHODS: We retrospectively analyzed 3 T MRI scans of 164 pregnant women in their second or third trimester, with (patient group, n = 60) and without previous CS (control group, n = 104). Sagittal T2-weighted images were studied. Normal findings of the LUS in MRI, reliability of MRI measurements, as well as factors influencing LUS thickness were assessed. MRI findings were compared to intraoperative findings. RESULTS: MRI provided good intra- (ICC 0.872) and fair inter-rater reliability (ICC 0.643). The relationship of the LUS and the cesarean scar to the surrounding anatomical structures and also its morphology varied strongly in patients and controls. Scar identification was possible in only 9/60 (15.0%) patients. The LUS was thinner in patients (1.9 ± 0.7 mm) than in controls (2.7 ± 1.3 mm). An LUS thinning up to 1 mm was observed in 23% of women without a previous CS and in 34% of women with normal intraoperative findings. Suspicion of a uterine dehiscence (LUS thickness < 1 mm) was only found in the patient group (5/59 (8.5%)) and was intraoperatively confirmed. In controls, LUS thickness was influenced by fetal weight, gestational age and amniotic fluid amounts. CONCLUSION: Variability in anatomy, thickness and morphology seem to limit common prenatal LUS imaging diagnostics. Therefore, we consider that diagnostic protocols must be re-evaluated and imaging should be adjusted to the individual patient conditions. Due to its independency of ultrasound limitations, an additional MRI might be useful for altered anatomy and impaired ultrasound conditions. An LUS thinning up to 1 mm might be a normal finding and should be further investigated as reference value.

In-bore biopsies of the prostate assisted by a remote-controlled manipulator at 1.5 T.

PURPOSE: To evaluate the technical and clinical utility of a fully MRI-compatible, pneumatically driven remote-controlled manipulator (RCM) for targeted biopsies of the prostate at 1.5 T. MATERIALS AND METHODS: The data of the first 22 patients that were biopsied under robotic assistance were analyzed. Interventional planning relied on T2-weighted (T2w) turbo spin-echo (TSE) images (axial and sagittal) with a high-b-value diffusion-weighted acquisition added in selected cases. Alignment of the needle guide was controlled with a short balanced SSFP sequence in two oblique planes along the MR-visible sheath. Signals were acquired with a combination of elements from a 30-channel body and a 32-channel spine coil. Biopsy samples were taken with a fully automatic 18-G biopsy gun with a length of 150 or 175 mm. RESULTS: Mean age was 66.6 years and average PSA level was 11.5 ng/ml. Fourteen out of 22 patients (63%) had received prior biopsies under transrectal ultrasound guidance. Diagnostic MRI reports (before biopsy) involved 17 cases with a single suspicious finding (four PI-RADS 3, one PI-RADS 3-4, eight PI-RADS 4 and nine PI-RADS 5 cases). The median effective procedure time was 33.9 (range 25.0-55.9) min for 16 cases with one CSR and 63.4 (52.7-81.8) min for 5 cases with two CSRs. The biopsy with three CSRs took 74.0 min. Histopathologic examination revealed prostate cancer in 14 of 22 cases. CONCLUSION: MR-targeted, transrectal biopsy of the prostate could be reliably performed with a robotic manipulator at a field strength of 1.5 T. Balanced SSFP imaging is considered a viable option for fast procedural control. Follow-up work needs to evaluate to what extent in-bore adjustments and workflow enhancements will contribute to shorter procedure times or higher patient comfort.

Cesarean section scar in 3 T magnetic resonance imaging and ultrasound: image characteristics and comparison of the methods.

PURPOSE: Uterine rupture during labor is a rare but life-threatening complication after previous cesarean section (CS). Prenatal risk is assessed using ultrasound thickness measurement of the lower uterine segment (LUS). Due to inhomogeneous study results, however, clinical obstetrics still lacks for standard protocols and reliable reference values. As 3 T magnetic resonance imaging (MRI) has not yet been sufficiently studied regarding LUS diagnostics after previous CS, we sought to evaluate its feasibility focusing on thickness measurements and typical characteristics of the CS-scar region in comparison to ultrasound and the intraoperative status. METHODS: In this prospective study, 25 asymptomatic patients with one previous CS and inconspicuous ultrasound findings were included. An additional 3 T MRI with either a T2-weighted Turbo-Spin-Echo or a Half Fourier-Acquired-Single-shot-Turbo-spin-Echo sequence in a sagittal orientation was performed. We analyzed categorical image quality, inter- and intra-rater reliability as well as anatomy, morphology and thickness of the LUS. Results were compared to ultrasound and intraoperative findings. RESULTS: MRI provided good to excellent image quality in all patients. The imaged structures presented with a high variability in anatomy and morphology. Image characteristics indicating the uterine scar were only found in 11/25 (44%) patients. LUS thickness measurements with MRI showed good inter- and intra-rater reliability but poor agreement with ultrasound. CONCLUSIONS: MRI is appropriate for additional LUS diagnostics in patients with previous CS. The strong individual variability of LUS-anatomy and morphology might explain the difficulties in establishing uniform diagnostic standards after CS.

Early Flow Disturbances of Tunnelled Haemodialysis Catheters and Topographic Landmarks in Chest X-Ray.

BACKGROUND/AIMS: The position of the tip of tunnelled haemodialysis (HD) catheters (THC) might influence flow characteristics during HD. In chest X-ray (CXR), carina-related landmarks may be practicable to verify the THC position, and tip-carina distance (TCD) might be useful to predict early-flow dysfunctions. METHODS: In this single-centre, retrospective study, the TCD and the angle between the distal catheter and the body vertical axis (tip-body vertical-angle [TVA]) was measured in 115 THC by post-procedure CXR with 2 investigators. The parameters were proved to be feasible by interrater-reliability and correlated with the incidence of flow-dysfunction within 10 days after insertion. RESULTS: Steep-aligned (TVA <40°, p < 0.01) and deep-ending catheters (TCD: right-sighted >1.5 cm or left-sighted >4.5 cm below the carina; p < 0.01) showed a significantly less dysfunction with a good interrater-reliability (R[TVA] = 0.8, R[TCD] = 0.9). CONCLUSIONS: Carina-related landmarks in CXR might be helpful to predict early-flow dysfunctions. However, randomized studies will be necessary to confirm this in fluoroscopic-guided placement during the insertion of THC.

Detection of Traumatic Bone Marrow Lesions after Knee Trauma: Comparison of ADC Maps Derived from Diffusion-weighted Imaging with Standard Fat-saturated Proton Density-weighted Turbo Spin-Echo Sequences.

Purpose To compare single-shot echo-planar diffusion-weighted imaging-derived apparent diffusion coefficient (ADC) maps with fat-saturated (FS) proton density (PD)-weighted turbo spin-echo (TSE) imaging in the detection of bone marrow lesions (BMLs) after knee trauma. Materials and Methods Institutional review board approval was obtained from Leipzig University. Written informed consent was waived. Three radiologists retrospectively re-examined 97 consecutive patients with reported knee trauma who underwent 1.5-T magnetic resonance (MR) imaging within 90 days of knee trauma. The following sequences were used: (a) sagittal T1-weighted TSE and FS PD-weighted TSE and (b) sagittal T1-weighted TSE and single-shot echo-planar diffusion-weighted imaging-derived ADC mapping. BMLs on the lateral and medial femoral condyle, lateral and medial aspect of the tibial plateau, and patella were documented. Volumetry was performed on BMLs with a thickness of at least 15 mm (major BMLs). ADC values were measured in intact bone marrow and major BMLs. A McNemar test and t tests were used as appropriate to test for significant differences between BML number and volume at an α level of .05. Results Significantly more patients showed at least one BML on ADC maps (98%, 95 of 97 patients) than on FS PD-weighted TSE images (86%, 84 of 97 patients) (P < .001). Of the affected regions detected on FS PD-weighted TSE images, 97% (170 of 175 regions) were identified consistently on ADC maps. Only 58% of the affected regions detected on ADC maps (170 of 293 regions) were identified on FS PD-weighted TSE images (P < .001). Median volume of concordant major BML was approximately two times larger on ADC maps (81 cm3) than on FS PD-weighted TSE images (39 cm3) (P < .001). The ADC values of intact bone marrow and BMLs did not overlap. Conclusion ADC maps are more sensitive than corresponding FS PD-weighted TSE images for detection of BML after knee trauma and allow detection of significantly more and larger BMLs. ADC map evaluation improves diagnostic performance in regions with insufficient spectral fat saturation, such as the patella. © RSNA, 2016 Online supplemental material is available for this article.

Value of diffusion-weighted MRI in diagnosis of uterine cervical cancer: a prospective study evaluating the benefits of DWI compared to conventional MR sequences in a 3T environment.

BACKGROUND: Imaging of cervical carcinoma remains challenging as local infiltration of surrounding tissues cannot always be discriminated safely. New imaging techniques, like diffusion-weighted imaging (DWI) have emerged, which could lead to a more sensitive tumor detection. PURPOSE: To evaluate the benefits of DWI for determination of size, local infiltration, and tumor grading, in patients with primary and recurrent cervical cancer. MATERIAL AND METHODS: In this prospective, study we enrolled 50 patients with primary (n = 35) and recurrent (n = 15) tumors. All patients underwent 3T magnetic resonance imaging (MRI) including conventional (e.g. T1/T2 ± fs ± contrast) sequences and DWI (b-values of 0, 50, 400, 800 s/mm(2)). All images were analyzed by three readers with different experience levels (1, 3, 6 years), who compared image quality, tumor delineation, dimensions, local infiltration, lymph node involvement, and quantified ADC values compared to the histopathological grading. RESULTS: Additional use of DWI resulted in significantly better (P < 0.001) tumor delineation for the least experienced reader, but not for experienced readers. Tumor dimensions were assessed almost equally (P > 0.05) in conventional sequences and DWI. Use of DWI led to an increase in sensitivity of infiltrated adjacent tissue (from 86% to 90%) and detection of lymph node metastases (from 47% to 67%). Quantitative assessment of carcinomas showed lower ADC values (P < 0.001) with significant inverse correlations between different grading levels. CONCLUSION: Our study demonstrates the overall benefits using DWI in 3T MRI resulting in a higher reader confidence, sensitivity of tissue infiltration, and tumor-grading for cervical cancer.

Physical and organizational provision for installation, regulatory requirements and implementation of a simultaneous hybrid PET/MR-imaging system in an integrated research and clinical setting.

The implementation of hybrid imaging systems requires thorough and anticipatory planning at local and regional levels. For installation of combined positron emission and magnetic resonance imaging systems (PET/MRI), a number of physical and constructional provisions concerning shielding of electromagnetic fields (RF- and high-field) as well as handling of radionuclides have to be met, the latter of which includes shielding for the emitted 511 keV gamma rays. Based on our experiences with a SIEMENS Biograph mMR system, a step-by-step approach is required to allow a trouble-free installation. In this article, we present a proposal for a standardized step-by-step plan to accomplish the installation of a combined PET/MRI system. Moreover, guidelines for the smooth operation of combined PET/MRI in an integrated research and clinical setting will be proposed. Overall, the most important preconditions for the successful implementation of PET/MRI in an integrated research and clinical setting is the interdisciplinary target-oriented cooperation between nuclear medicine, radiology, and all referring and collaborating institutions at all levels of interaction (personnel, imaging protocols, reporting, selection of the data transfer and communication methods).

Students benefit from developing their own emergency medicine OSCE stations: a comparative study using the matched-pair method.

BACKGROUND: Students can improve the learning process by developing their own multiple choice questions. If a similar effect occurred when creating OSCE (objective structured clinical examination) stations by themselves it could be beneficial to involve them in the development of OSCE stations. This study investigates the effect of students developing emergency medicine OSCE stations on their test performance. METHOD: In the 2011/12 winter semester, an emergency medicine OSCE was held for the first time at the Faculty of Medicine at the University of Leipzig. When preparing for the OSCE, 13 students (the intervention group) developed and tested emergency medicine examination stations as a learning experience. Their subsequent OSCE performance was compared to that of 13 other students (the control group), who were parallelized in terms of age, gender, semester and level of previous knowledge using the matched-pair method. In addition, both groups were compared to 20 students who tested the OSCE prior to regular emergency medicine training (test OSCE group). RESULTS: There were no differences between the three groups regarding age (24.3 ± 2.6; 24.2 ± 3.4 and 24 ± 2.3 years) or previous knowledge (29.3 ± 3.4; 29.3 ± 3.2 and 28.9 ± 4.7 points in the multiple choice [MC] exam in emergency medicine). Merely the gender distribution differed (8 female and 5 male students in the intervention and control group vs. 3 males and 17 females in the test OSCE group).In the exam OSCE, participants in the intervention group scored 233.4 ± 6.3 points (mean ± SD) compared to 223.8 ± 9.2 points (p < 0.01) in the control group. Cohen's effect size was d = 1.24. The students of the test OSCE group scored 223.2 ± 13.4 points. CONCLUSIONS: Students who actively develop OSCE stations when preparing for an emergency medicine OSCE achieve better exam results.

High-intensity focused ultrasound (HIFU) hemiablation of the prostate: Late follow-up MRI findings in non-recurrent patients.

OBJECTIVES: Focal therapy with high-intensity focused ultrasound (HIFU) is an emerging option for the treatment of prostate cancer and often followed up by MRI. Image assessment of treatment failure, however, requires proper knowledge about typical procedure-related changes in prostate MRI, which is sparse, in particular for unilateral HIFU treatment and late follow up (beyond 6 months). The goal of this study was therefore to compile the type and frequency of such MRI findings in selected patients without recurrent cancer 12 months after prostate hemiablation. METHODS: Data from a prospective multicenter trial on HIFU hemiablation were reviewed retrospectively. Trial patients have had a late follow-up by MRI (at around 12 months) and either MRI/transrectal ultrasound (TRUS) fusion or standard TRUS-guided biopsy. This work deliberately included patients with non-recurrent cancer in the treated prostate lobe in per-protocol biopsy leaving 30 men with initial International Society of Urological Pathology (ISUP) Grade Group of 1 or 2. Six categories of potential HIFU-related MRI features were assessed by an expert committee and then evaluated by two readers in consensus: 1. shrinkage of the treated lobe, 2. residual prostate tissue, 3. fluid-filled cavity, 4. fibrosis, 5. hematoma residuals (in the prostate or seminal vesicles) and 6. contrast enhancement of the ablated area. RESULTS: Shrinkage of the ablated lobe was seen in 93% of the cases with an average percent volume change of -37% (range: -70% to +108%). In the contralateral lobe, the volume remained practically the same (-2% on average, p = 0.804). In the ablated lobe, the frequency of fibrosis was 97%. Residual prostate tissue was seen in 93% of the cases. The frequency for fluid-filled cavities was 97%, with the wide majority (90%) contiguous with the urethra. Hematoma residuals in the prostate and in seminal vesicles were found in 47% and 10% of the patients, respectively. Contrast enhancement was both rim-like (50%) as well as diffuse (33%) within the ablated area. CONCLUSION: In our case series of HIFU hemiablation in the prostate, shrinkage, residual prostate tissue, fluid-filled cavities contiguous with the urethra and fibrosis were very common late MRI findings of the ablated lobe in non-recurrent patients. Rim-like contrast enhancement or diffuse one within the ablated area were less frequent.

Quantification of radiation dose savings in cardiac computed tomography using prospectively triggered mode and ECG pulsing: a phantom study.

OBJECTIVE: To quantify radiation dose reduction in cardiac computed tomography (CT) using a prospectively triggered mode compared with a retrospective ECG-gated helical mode. METHODS: Absorbed organ doses in cardiac 64-row multidetector CT were quantified using an anthropomorphic male Alderson phantom with 74 thermoluminescence dosimeters. Three different imaging protocols were applied: retrospective ECG-gating, retrospective ECG-gating with additional ECG-pulsing, and a prospectively triggered mode. The measured organ doses were compared with dose estimation by a mathematical phantom. RESULTS: Compared with the retrospective ECG-gating mode, the mean relative organ doses were reduced by 44% using ECG pulsing and by 76% using the prospectively triggered mode. The range of dose savings varied from 34% to 49% using ECG pulsing and from 65% to 87% using the prospectively triggered mode. The effective dose was 16.5 mSv using retrospective gating, 9.2 mSv using retrospective gating with ECG pulsing and 4.0 mSv using the prospectively triggered mode. CONCLUSIONS: Our measurements confirm the high dose-saving potential of the prospectively triggered technique in cardiac CT. The reduction in the organ doses measured corresponds to estimates determined by the mathematical phantom. The effective dose calculated by the mathematical phantom was, in some cases, significantly lower than that calculated using the anthropomorphic phantom.

Clinical consequences of chest tube malposition in trauma resuscitation: single-center experience.

PURPOSE: Evaluation of trauma patients with chest tube malposition using initial emergency computed tomography (CT) and assessment of outcomes and the need for chest tube replacement. METHODS: Patients with an injury severity score > 15, admitted directly from the scene, and requiring chest tube insertion prior to initial emergency CT were retrospectively reviewed. Injury severity, outcomes, and the positions of chest tubes were analyzed with respect to the need for replacement after CT. RESULTS: One hundred seven chest tubes of 78 patients met the inclusion criteria. Chest tubes were in the pleural space in 58% of cases. Malposition included intrafissural positions (27%), intraparenchymal positions (11%) and extrapleural positions (4%). Injury severity and outcomes were comparable in patients with and without malposition. Replacement due to malfunction was required at similar rates when comparing intrapleural positions with both intrafissural or intraparenchymal positions (11 vs. 23%, p = 0.072). Chest tubes not reaching the target position (e.g., pneumothorax) required replacement more often than targeted tubes (75 vs. 45%, p = 0.027). Out-of-hospital insertions required higher replacement rates than resuscitation room insertions (29 vs. 10%, p = 0.016). Body mass index, chest wall thickness, injury severity, insertion side and intercostal space did not predict the need for replacement. CONCLUSIONS: Patients with malposition of emergency chest tubes according to CT were not associated with worse outcomes compared to patients with correctly positioned tubes. Early emergency chest CT in the initial evaluation of severely injured patients allows precise detection of possible malposition of chest tubes that may require immediate intervention.

Mechanical complications and outcomes following invasive emergency procedures in severely injured trauma patients.

This study aimes to determine the complication rates, possible risk factors and outcomes of emergency procedures performed during resuscitation of severely injured patients. The medical records of patients with an injury severity score (ISS) >15 admitted to the University Hospital Leipzig from 2010 to 2015 were reviewed. Within the first 24 hours of treatment, 526 patients had an overall mechanical complication rate of 26.2%. Multivariate analysis revealed out-of-hospital airway management (OR 3.140; 95% CI 1.963-5.023; p < 0.001) and ISS (per ISS point: OR 1.024; 95% CI 1.003-1.045; p = 0.027) as independent predictors of any mechanical complications. Airway management complications (13.2%) and central venous catheter complications (11.4%) were associated with ISS >32.5 (p < 0.001) and ISS >33.5 (p = 0.005), respectively. Chest tube complications (15.8%) were associated with out-of-hospital insertion (p = 0.002) and out-of-hospital tracheal intubation (p = 0.033). Arterial line complications (9.4%) were associated with admission serum lactate >4.95 mmol/L (p = 0.001) and base excess <-4.05 mmol/L (p = 0.008). In multivariate analysis, complications were associated with an increased length of stay in the intensive care unit (p = 0.019) but not with 24 hour mortality (p = 0.930). Increasing injury severity may contribute to higher complexity of the individual emergency treatment and is thus associated with higher mechanical complication rates providing potential for further harm.

Central venous catheterization for acute trauma resuscitation: Tip position analysis using routine emergency computed tomography.

PURPOSE: Central venous catheter insertion for acute trauma resuscitation may be associated with mechanical complications, but studies on the exact central venous catheter tip positions are not available. The goal of the study was to analyze central venous catheter tip positions using routine emergency computed tomography. METHODS: Consecutive acute multiple trauma patients requiring large-bore thoracocervical central venous catheters in the resuscitation room of a university hospital were enrolled retrospectively from 2010 to 2015. Patients who received a routine emergency chest computed tomography were analyzed regarding central venous catheter tip position. The central venous catheter tip position was defined as correct if the catheter tip was placed less than 1 cm inside the right atrium relative to the cavoatrial junction, and the simultaneous angle of the central venous catheter tip compared with the lateral border of the superior vena cava was below 40°. RESULTS: During the 6-year study period, 97 patients were analyzed for the central venous catheter tip position in computed tomography. Malpositions were observed in 29 patients (29.9%). Patients with malpositioned central venous catheters presented with a higher rate of shock (systolic blood pressure <90 mmHg) at admission (58.6% vs 33.8%, p = 0.023) and a higher mean injury severity score (38.5 ± 15.7 vs 31.6 ± 11.8, p = 0.041) compared with patients with correctly positioned central venous catheter tips. Logistic regression revealed injury severity score as a significant predictor for central venous catheter malposition (odds ratio = 1.039, 95% confidence interval = 1.005-1.074, p = 0.024). CONCLUSION: Multiple trauma patients who underwent emergency central venous catheter placement by experienced anesthetists presented with considerable tip malposition in computed tomography, which was significantly associated with a higher injury severity.

Characterization of Severe Arterial Phase Respiratory Motion Artifact on Gadoxetate Disodium-Enhanced MRI - Assessment of Interrater Agreement and Reliability.

PURPOSE: To assess the interrater agreement and reliability of experienced abdominal radiologists in the characterization and grading of arterial phase gadoxetate disodium-related respiratory motion artifact on liver MRI. MATERIALS AND METHODS: This prospective multicenter study was initiated by the working group for abdominal imaging within the German Roentgen Society (DRG), and approved by the local IRB of each participating center. 11 board-certified radiologists independently reviewed 40 gadoxetate disodium-enhanced liver MRI datasets. Motion artifacts in the arterial phase were assessed on a 5-point scale. Interrater agreement and reliability were calculated using the intraclass correlation coefficient (ICC) and Kendall coefficient of concordance (W), with p < 0.05 deemed significant. RESULTS: The ICC for interrater agreement and reliability were 0.983 (CI 0.973 - 0.990) and 0.985 (CI 0.978 - 0.991), respectively (both p < 0.0001), indicating excellent agreement and reliability. Kendall's W for interrater agreement was 0.865. A severe motion artifact, defined as a mean motion score ≥ 4 in the arterial phase was observed in 12 patients. In these specific cases, a motion score ≥ 4 was assigned by all readers in 75 % (n = 9/12 cases). CONCLUSION: Differentiation and grading of arterial phase respiratory motion artifact is possible with a high level of inter-/intrarater agreement and interrater reliability, which is crucial for assessing the incidence of this phenomenon in larger multicenter studies. KEY POINTS: · Inter- and intrarater agreement for motion artifact scoring is excellent among experienced readers.. · Interrater reliability for motion artifact scoring is excellent among experienced readers.. · Characterization of severe motion artifacts proved feasible in this multicenter study.. CITATION FORMAT: · Ringe KI, Luetkens JA, Fimmers R et al. Characterization of Severe Arterial Phase Respiratory Motion Artifact on Gadoxetate Disodium-Enhanced MRI - Assessment of Interrater Agreement and Reliability. Fortschr Röntgenstr 2017; 190: 341 - 347.

Associations between 18F-FDG-PET, DWI, and DCE Parameters in Patients with Head and Neck Squamous Cell Carcinoma Depend on Tumor Grading.

Our purpose was to analyze associations between positron emission tomography (PET), diffusion weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging in patients with head and neck squamous cell carcinoma (HNSCC). The study involved 34 patients (9 women, 25 men, mean age: 56.7 ± 10.2 years). In all patients a simultaneous 18F-FDG-PET/MR was performed. DWI was obtained by using of an axial EPI sequence. Minimal ADC values (ADCmin), mean ADC values (ADCmean), and maximal ADC values (ADCmax) were estimated. DCE MRI was performed by using dynamic T1w DCE sequence. The following parameters were estimated: Ktrans, Ve , and Kep. Spearman's correlation coefficient was used to analyze associations between investigated parameters. In overall sample, ADCmean correlated significantly with Ve and Ktrans, ADCmin correlated with Ve , and ADCmax correlated with Ktrans and Ve . SUVmean tended to correlate slightly with Ktrans. In G1/2 tumors, only Ktrans correlated well with ADCmax and SUVmean. In G3 tumors, Ktrans correlated well with Kep and Ve . Ve showed significant correlations with ADCmean and ADCmax. Ktrans correlated with ADCmax. Kep was higher in cancers with N2/3 stages. Tumor metabolism, water diffusion, and tumor perfusion have complex relationships in HNSCC. Furthermore, these associations depend on tumor grading. Kep may predict lymphonodal metastasizing.

Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies.

Purpose Analysis of patient´s X-ray exposure during percutaneous radiologic gastrostomies (PRG) in a larger population. Materials and Methods Data of primary successful PRG-procedures, performed between 2004 and 2015 in 146 patients, were analyzed regarding the exposition to X-ray. Dose-area-product (DAP), dose-length-product (DLP) respectively, and fluoroscopy time (FT) were correlated with the used x-ray systems (Flatpanel Detector (FD) vs. Image Itensifier (BV)) and the necessity for periprocedural placement of a nasogastric tube. Additionally, the effective X-ray dose for PRG placement using fluoroscopy (DL), computed tomography (CT), and cone beam CT (CBCT) was estimated using a conversion factor. Results The median DFP of PRG-placements under fluoroscopy was 163 cGy*cm2 (flat panel detector systems: 155 cGy*cm2; X-ray image intensifier: 175 cGy*cm2). The median DLZ was 2.2 min. Intraprocedural placement of a naso- or orogastric probe (n = 68) resulted in a significant prolongation of the median DLZ to 2.5 min versus 2 min in patients with an already existing probe. In addition, dose values were analyzed in smaller samples of patients in which the PRG was placed under CBCT (n = 7, median DFP = 2635 cGy*cm2), or using CT (n = 4, median DLP = 657 mGy*cm). Estimates of the median DFP and DLP showed effective doses of 0.3 mSv for DL-assisted placements (flat panel detector 0.3 mSv, X-ray image converter 0.4 mSv), 7.9 mSv using a CBCT - flat detector, and 9.9 mSv using CT. This corresponds to a factor 26 of DL versus CBCT, or a factor 33 of DL versus CT. Conclusion In order to minimize X-ray exposure during PRG-procedures for patients and staff, fluoroscopically-guided interventions should employ flat detector systems with short transmittance sequences in low dose mode and with slow image frequency. Series recordings can be dispensed with. The intraprocedural placement of a naso- or orogastric probe significantly extends FT, but has little effect on the overall dose of the intervention. Due to the significantly higher X-ray exposure, the use of a CBCT as well as PRG-placements using CT should be limited to clinically absolutely necessary exceptions with strict indication. Key Points · Fluoroscopically-guided PRG placements are interventions with low X-ray exposure.. · X-ray exposure from fluoroscopy is lower using flat panel detector systems as compared to image intensifier systems.. · The concomitant placement of an oro- or nasogastric probe extends the fluoroscopy time.. · Gastric probe placement is worthwhile to prevent the premature use of the significantly radiation-intensive CT.. · The use of the C-arm CT or the CT increases the beam exposure by 26 or 33 times, respectively.. · The PRG placement using C-arm CT and CT should only be performed in exceptional cases.. Citation Format · Petersen TO, Reinhardt M, Fuchs J et al. Analysis of Patients' X-ray Exposure in 146 Percutaneous Radiologic Gastrostomies. Fortschr Röntgenstr 2017; 189: 820 - 827.

Correlations Between DCE MRI and Histopathological Parameters in Head and Neck Squamous Cell Carcinoma.

BACKGROUND: Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) can characterize perfusion and vascularization of tissues. DCE MRI parameters can differentiate between malignant and benign lesions and predict tumor grading. The purpose of this study was to correlate DCE MRI findings and various histopathological parameters in head and neck squamous cell carcinoma (HNSCC). PATIENTS AND METHODS: Sixteen patients with histologically proven HNSCC (11 cases primary tumors and in 5 patients with local tumor recurrence) were included in the study. DCE imaging was performed in all cases and the following parameters were estimated: Ktrans, Ve, Kep, and iAUC. The tumor proliferation index was estimated on Ki 67 antigen stained specimens. Microvessel density parameters (stained vessel area, total vessel area, number of vessels, and mean vessel diameter) were estimated on CD31 antigen stained specimens. Spearman's non-parametric rank sum correlation coefficients were calculated between DCE and different histopathological parameters. RESULTS: The mean values of DCE perfusion parameters were as follows: Ktrans 0.189 ± 0.056 min-1, Kep 0.390 ± 0.160 min-1, Ve 0.548 ± 0.119%, and iAUC 22.40 ± 12.57. Significant correlations were observed between Kep and stained vessel areas (r = 0.51, P = .041) and total vessel areas (r = 0.5118, P = .043); between Ve and mean vessel diameter (r = -0.59, P = .017). Cell count had a tendency to correlate with Ve (r = -0.48, P = .058). In an analysis of the primary HNSCC only, a significant inverse correlation between Ktrans and KI 67 was identified (r = -0.62, P = .041). Our analysis showed significant correlations between DCE parameters and histopathological findings in HNSCC.

Parameters of simultaneous 18F-FDG-PET/MRI predict tumor stage and several histopathological features in uterine cervical cancer.

The purpose of this study was to analyze associations between apparent diffusion coefficient (ADC) and standardized uptake values (SUV) values and different histopathological parameters in uterine cervical cancer. 21 patients with primary uterine cervical cancer were involved into the study. All patients underwent a whole body simultaneous18F-FDG PET/MRI. Mean and maximum SUV were noted (SUVmean and SUVmax). In all tumors minimal, mean, and maximal ADC values (ADCmin, ADCmean, and ADCmax) were estimated. Combined parameters were calculated: SUVmax/SUVmean, ADCmin/ ADCmean, SUVmax/ADCmin and SUVmax/ADCmean. In all cases the diagnosis was confirmed histopathologically by tumor biopsy. Histological slices were stained by hematoxilin and eosin, MIB 1 monoclonal antibody, and p16. All histopathological images were digitalized and analyzed by using a ImageJ software 1.48v. The following parameters were estimated: cell count, proliferation index KI 67, total and average nucleic areas, epithelial and stromal areas. Spearman's correlation coefficient was used to analyze associations between ADC and SUV values and histological parameters. P values ≤ 0.05 were considered as statistically significant. ADCmin and ADCmin/ ADCmean were statistically significant lower in N positive tumors. KI 67 correlated statistically significant with SUVmax (r = 0.59, p = 0.005), SUVmean (0.45, p = 0.04), ADCmin (r = -0.48, p = 0.03), SUVmax/ADCmin (r = 0.71, p = 0.001), SUVmax/ADCmean (0.75, p = 0.001). SUVmax correlated well with epithelial area (r = 0.71, p = 0.001) and stromal areas (r = -0.71, p = 0.001). SUV values, ADCmin, SUVmax/ADCmin and SUVmax/ADCmean correlated statistically significant with KI 67 and can be used to estimate the proliferation potential of tumors. SUV values correlated strong with epithelial area of tumor reflected metabolic active areas.

Induction chemotherapy followed by radiotherapy for larynx preservation in advanced laryngeal and hypopharyngeal cancer: Outcome prediction after one cycle induction chemotherapy by a score based on clinical evaluation, computed tomography-based volumetry and 18F-FDG-PET/CT.

BACKGROUND: Long-term laryngectomy-free (LFS), tumour-specific (TSS) and overall survival (OS) is achieved by non-surgical larynx preservation (LP) only in a proportion of patients with locally advanced laryngeal or hypopharyngeal cancer. A score facilitating decision-making after 1 cycle induction chemotherapy (IC-1) may improve LFS and TSS. METHODS: Early response to IC-1 with TPF ± cetuximab was assessed in 52 patients using endoscopic tumour staging for selecting total laryngectomy for non-responders with endoscopic tumour surface shrinkage <30% versus induction chemotherapy plus radiotherapy (IC + RT) for responders. Computed tomography (CT)-based volumetry was used to assess volumes of primary tumour, neck nodes and their sum; maximum and mean standardised uptake value (SUVmax, SUVmean) were measured by 18F-FDG-PET/CT. Baseline and residual values after IC-1 were calculated and correlated with LFS, TSS and OS. RESULTS: After IC-1, 39/52 patients (75%) were early responders. Early response predicted complete response to IC + RT (p = 8.48 × 10-9). Early laryngectomised non-responders and responders with endoscopic tumour surface shrinkage > 70% had best OS. Significant independent predictors for LFS in responders are number of CT-staged suspect positive neck nodes (N+), residual primary tumour volume, residual total tumour volume and the ratio of residual SUVmax and SUVmean (resSUVmax/resSUVmean). Our LFS-score combines >2N+, residual primary tumour volume > 20%, residual total tumour volume > 5.6 mL and resSUVmax/resSUVmean > 1.51 weighted by their hazard ratio (12, 6, 5 and 4); LFS-score ≤ 16 predicts increased LFS, OS and TSS (p < 0.05). CONCLUSION: LFS-score ≤ 16 identifies in responders to IC-1 the patients with maximum benefit of non-surgical LP achieving long-term LFS. Even more importantly, a LFS-score > 16 defines patients unsuitable for LP applying the TPF/TP IC + RT protocol.