Preoperative Perforator Mapping in DIEP Flaps for Breast Reconstruction. The Impact of New Contrast-Enhanced Ultrasound Techniques.

Deep inferior epigastric artery flaps (DIEP) represent the gold standard of autologous breast reconstruction. Due to significant variations in vascular anatomy, preoperative perforator mapping (PM) is mandatory in order to ensure the presence of a sufficient perforator within the flap. In this regard, CT angiography (CTA) is currently the method of choice. Therefore, we investigated the value of contrast-enhanced ultrasound (CEUS) techniques for preoperative PM in comparison to CTA. Patients underwent PM, utilizing both CTA and CEUS techniques. Documentation included the course of the vascular pedicle through the rectus muscle (M), fascial penetration (F), the subcutaneous plexus (P) and the skin point (SP) on either side of the abdomen. Thus, contrast-enhanced B-Flow (BCEUS), B-Flow ultrasound (BUS), CEUS, color Doppler ultrasound (CDUS) and CTA were evaluated in terms of the diagnostic consistency and effectiveness of PM. Precision (∆L) was then calculated in relation to the actual intraoperative location. Statistical analysis included Kruskall-Wallis, Levene and Bonferroni tests, as well as Spearman correlations. A total of 39 DIEP flaps were analyzed. Only CTA (∆L = 2.85 mm) and BCEUS (∆L = 4.57 mm) enabled complete PM, also including P and SP, whereas CDUS, CEUS and BUS enabled clear PM throughout M and F only. Regarding the number of detected perforators, PM techniques are ranked from high to low as follows: CTA, BCEUS, BUS, CEUS and CDUS. CTA and BCEUS showed sufficient diagnostic consistency for SP, P and F, while CDUS and CTA had a superior performance for M. BCEUS offers precise image-controlled surface tags and dynamic information for PM without imposing radiation and may, therefore, be considered a feasible add-on or alternative to CTA. However, BCEUS requires an experienced examiner and is more time-consuming.

Primary renal sarcomas: imaging features and discrimination from non-sarcoma renal tumors.

OBJECTIVES: To assess imaging features of primary renal sarcomas in order to better discriminate them from non-sarcoma renal tumors. METHODS: Adult patients diagnosed with renal sarcomas from 1995 to 2018 were included from 11 European tertiary referral centers (Germany, Belgium, Turkey). Renal sarcomas were 1:4 compared to patients with non-sarcoma renal tumors. CT/MRI findings were assessed using 21 predefined imaging features. A random forest model was trained to predict "renal sarcoma vs. non-sarcoma renal tumors" based on demographics and imaging features. RESULTS: n = 34 renal sarcomas were included and compared to n = 136 non-sarcoma renal tumors. Renal sarcomas manifested in younger patients (median 55 vs. 67 years, p < 0.01) and were more complex (high RENAL score complexity 79.4% vs. 25.7%, p < 0.01). Renal sarcomas were larger (median diameter 108 vs. 43 mm, p < 0.01) with irregular shape and ill-defined margins, and more frequently demonstrated invasion of the renal vein or inferior vena cava, tumor necrosis, direct invasion of adjacent organs, and contact to renal artery or vein, compared to non-sarcoma renal tumors (p < 0.05, each). The random forest algorithm yielded a median AUC = 93.8% to predict renal sarcoma histology, with sensitivity, specificity, and positive predictive value of 90.4%, 76.5%, and 93.9%, respectively. Tumor diameter and RENAL score were the most relevant imaging features for renal sarcoma identification. CONCLUSION: Renal sarcomas are rare tumors commonly manifesting as large masses in young patients. A random forest model using demographics and imaging features shows good diagnostic accuracy for discrimination of renal sarcomas from non-sarcoma renal tumors, which might aid in clinical decision-making. KEY POINTS: • Renal sarcomas commonly manifest in younger patients as large, complex renal masses. • Compared to non-sarcoma renal tumors, renal sarcomas more frequently demonstrated invasion of the renal vein or inferior vena cava, tumor necrosis, direct invasion of adjacent organs, and contact to renal artery or vein. • Using demographics and standardized imaging features, a random forest showed excellent diagnostic performance for discrimination of sarcoma vs. non-sarcoma renal tumors (AUC = 93.8%, sensitivity = 90.4%, specificity = 76.5%, and PPV = 93.9%).

First description of hematogenously metastasized sclerosing epithelioid fibrosarcoma arising in the uterine cervix.

•First Case of hematogenously metastasized sclerosing epithelioid fibrosarcoma arising primarily in the cervix uteri.•Tumor cells were strongly and diffusely positive for MUC4.•Tumor showed a rare EWSR1-CREB3L2 gene fusion.

Ex Vivo Study of Artifacts Caused by Breast Tissue Markers with Different 1.5 Tesla and 3 Tesla MRI Scanners - A Bicentric Study.

RATIONALE AND OBJECTIVES: The purpose of our study was to evaluate magnetic resonance (MR) artifacts related to breast tissue markers in breast imaging procedures. MATERIALS AND METHODS: In this bicentric prospective ex vivo study 10 different commercially available markers were measured in self-made breast phantoms. Breast tissue markers varying in marker size, composition, and shape were evaluated. MR imaging (MRI) scans were performed on 1.5 Tesla (T) and 3 T scanners from 2 different vendors, using dedicated breast coils. Three different sequences (T1-weighted images with and without fat saturation, T2-weighted images) were acquired in axial and coronal view. Three blinded readers electronically measured the artifact length. RESULTS: All markers caused artifacts in MRI. The largest median artifact length was 10.4 mm, interquartile range (IQR 9.4-11.0 mm), the smallest 4.8 mm (IQR 4.5-5.2 mm). Relative artifact length (quotient artifact length in mm/real physical length of the marker) ranged between 0.9 (IQR 0.9-1.2) and 3.0 (IQR 2.8-3.4). Mean artifact length was higher for metallic markers (10.2 mm; IQR 8.7-11.5 mm) compared to metallic markers with nonmetallic coating (7.7 mm; IQR 6.3-10.2 mm) and nonmetallic marker (7.6 mm; IQR 5.9-10.0 mm); all p < 0.0001. Artifact size was higher in coronal in comparison to axial view; p < 0.05. The results were comparable between the different field strengths, the sites and sequences; p > 0.05. Interobserver agreement was excellent (ntraclass correlation coefficient = 0.83). CONCLUSION: Artifacts are necessary in the detection and localization of breast tissue markers, but could also limit the interpretation of MRI due to the possibility of masking the residual tumor after biopsy. This artifact size varies among the different clips evaluated. It depends on marker composition and scan direction but is not influenced by image sequence, field strength or scanner type.

Semiautomated Renal Cortex Volumetry in Multislice Computed Tomography: Effect of Slice Thickness and Iterative Reconstruction Algorithms.

OBJECTIVE: The aim of the study was to evaluate the effect of slice thickness, iterative reconstruction (IR) algorithm, and kernel selection on measurement accuracy and interobserver variability for semiautomated renal cortex volumetry (RCV) with multislice computed tomography (CT). METHODS: Ten patients (62.4 ± 17.2 years) undergoing abdominal biphasic multislice computed tomography were enrolled in this retrospective study. Computed tomography data sets were reconstructed at 1-, 2-, and 5-mm slice thickness with 2 different IR algorithms (iDose, IMRST) and 2 different kernels (IMRS and IMRR) (Philips, the Netherlands). Two readers independently performed semiautomated RCV for each reconstructed data set to calculate left kidney volume (LKV) and split renal function (SRF). Statistics were calculated using analysis of variance with Geisser-Greenhouse correction, followed by Tukey multiple comparisons post hoc test. Statistical significance was defined as P ≤ 0.05. RESULTS: Semiautomated RCV of 120 data sets (240 kidneys) was successfully performed by both readers. Semiautomated RCV provides comparable results for LKV and SRF with 3 different slice thicknesses, 2 different IR algorithms, and 2 different kernels. Only the 1-mm slice thickness showed significant differences for LKV between IMRR and IMRS (P = 0.02, mean difference = 4.28 bb) and IMRST versus IMRS (P = 0.02, mean difference = 4.68 cm) for reader 2. Interobserver variability was low between both readers irrespective of slice thickness and reconstruction algorithm (0.82 ≥ P ≥ 0.99). CONCLUSIONS: Semiautomated RCV measurements of LKV and SRF are independent of slice thickness, IR algorithm, and kernel selection. These findings suggest that comparisons between studies using different slice thicknesses and reconstruction algorithms for RCV are valid.

Magnetic Resonance-Guided High-Intensity Focused Ultrasound (MR-HIFU): Overview of Emerging Applications (Part 2).

BACKGROUND: High-intensity focused ultrasound (HIFU) allows noninvasive heating of deep-seated tissues. Guidance under magnetic resonance imaging (MR-HIFU) offers spatial targeting based on anatomical MR images as well as MR-based near-real-time temperature maps. Temperature feedback allows delivery of a well-defined thermal dose enabling new applications such as the ablation of malignant tissue. METHODS: Peer-reviewed publications on MR-HIFU were studied and are summarized in this review. Literature was restricted to applications in oncology. RESULTS: Several MR-HIFU-based applications for the treatment of malignant diseases are currently part of clinical trials or translational research. Recent trials regarding the treatment of prostate cancer with MR-HIFU have already shown this to be a safe and patient-friendly method. For the treatment of breast cancer and malignancies within abdominal organs, MR-HIFU has been applied so far only in proof of concept studies. CONCLUSION: MR-HIFU is currently being investigated for the ablative treatment of malignant tissue in a variety of oncological applications. For example, the transrectal as well as transurethral ablation of prostate cancer using MR-HIFU was shown to be a patient-friendly, safe alternative to other local treatment options with low side effects. KEY POINTS: · MR guidance offers high soft tissue contrast for treatment planning, near-real-time temperature monitoring, and post-interventional therapy evaluation.. · Special HIFU transducers and technological solutions are available for the treatment of e. g. prostate cancer, breast cancer or abdominal malignancies.. CITATION FORMAT: · Siedek F, Yeo SY, Heijman E et al. MR-Guided High-Intensity Focused Ultrasound (MR-HIFU): Overview of Emerging Applications (Part 2). Fortschr Röntgenstr 2019; 191: 531 - 539.

Magnetic Resonance-Guided High-Intensity Focused Ultrasound (MR-HIFU): Technical Background and Overview of Current Clinical Applications (Part 1).

BACKGROUND: Extracorporeal high-intensity focused ultrasound (HIFU) is a promising method for the noninvasive thermal ablation of benign and malignant tissue. Current HIFU treatments are performed under ultrasound (US-HIFU) or magnetic resonance (MR-HIFU) image guidance offering integrated therapy planning, real-time control (spatial and temperature guidance) and evaluation. METHODS: This review is based on publications in peer-reviewed journals addressing thermal ablation using HIFU and includes our own clinical results as well. The technical background of HIFU is explained with an emphasis on MR-HIFU applications. A brief overview of the most commonly performed CE-approved clinical applications for MR-HIFU is given. RESULTS: Over the last decade, several HIFU-based applications have received clinical approval in various countries. In particular, MR-HIFU is now approved for the clinical treatment of uterine fibroids, palliation of bone pain, ablation of the prostate and treatment of essential tremor as a first neurological application. CONCLUSION: MR-HIFU is a patient-friendly noninvasive method for thermal ablation which has received clinical approval for several applications. Overall, clinical data demonstrate treatment efficacy, safety and cost efficiency. KEY POINTS: · HIFU is a promising technique for noninvasive thermal ablation of tissue.. · HIFU is typically performed under image guidance using either diagnostic ultrasound (US-HIFU) or MRI (MR-HIFU).. · The preferred image guidance modality depends on the application.. · MR guidance offers improved soft-tissue contrast for treatment planning, near real-time and noninvasive temperature monitoring and post-interventional therapy evaluation.. · MR-HIFU is CE-approved for treatment of uterine fibroids, alleviation of bone pain, prostate tissue ablation and treatment of essential tremor.. CITATION FORMAT: · Siedek F, Yeo S, Heijman E et al. Magnetic Resonance-Guided High-Intensity Focused Ultrasound (MR-HIFU): Technical Background and Overview of Current Clinical Applications (Part 1). Fortschr Röntgenstr 2019; 191: 522 - 530.

Genomic Profiling Identifies Outcome-Relevant Mechanisms of Innate and Acquired Resistance to Third-Generation Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Therapy in Lung Cancer.

PURPOSE: Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are effective in acquired resistance (AR) to early-generation EGFR TKIs in EGFR-mutant lung cancer. However, efficacy is marked by interindividual heterogeneity. We present the molecular profiles of pretreatment and post-treatment samples from patients treated with third-generation EGFR TKIs and their impact on treatment outcomes. METHODS: Using the databases of two lung cancer networks and two lung cancer centers, we molecularly characterized 124 patients with EGFR p.T790M-positive AR to early-generation EGFR TKIs. In 56 patients, correlative analyses of third-generation EGFR TKI treatment outcomes and molecular characteristics were feasible. In addition, matched post-treatment biopsy samples were collected for 29 patients with progression to third-generation EGFR TKIs. RESULTS: Co-occurring genetic aberrations were found in 74.4% of EGFR p.T790-positive samples (n = 124). Mutations in TP53 were the most frequent aberrations detected (44.5%; n = 53) and had no significant impact on third-generation EGFR TKI treatment. Mesenchymal-epithelial transition factor (MET) amplifications were found in 5% of samples (n = 6) and reduced efficacy of third-generation EGFR TKIs significantly (eg, median progression-free survival, 1.0 months; 95% CI, 0.37 to 1.72 v 8.2 months; 95% CI, 1.69 to 14.77 months; P ≤ .001). Genetic changes in the 29 samples with AR to third-generation EGFR TKIs were found in EGFR (eg, p.T790M loss, acquisition of p.C797S or p.G724S) or in other genes (eg, MET amplification, KRAS mutations). CONCLUSION: Additional genetic aberrations are frequent in EGFR-mutant lung cancer and may mediate innate and AR to third-generation EGFR TKIs. MET amplification was strongly associated with primary treatment failure and was a common mechanism of AR to third-generation EGFR TKIs. Thus, combining EGFR inhibitors with TKIs targeting common mechanisms of resistance may delay AR.

Can computed tomography volumetry of the renal cortex replace MAG3-scintigraphy in all patients for determining split renal function?

OBJECTIVES: The current gold standard for determination of split renal function (SRF) is Tc-99m-mercapto-acetyltriglycin (MAG3) scintigraphy. Initial studies comparing MAG3-scintigraphy and CT-based renal cortex volumetry (RCV) for calculation of SRF have shown similar results in highly selected patient collectives with normal renal function (i.e. living kidney donors). This study aims to compare MAG3-scintigraphy and CT-RCV within a large unselected patient collective including patients with impaired renal function. MATERIALS AND METHODS: For this assessment, 279 datasets (131 men, 148 women; mean age: 54.2 ±â€¯12.9 years, range: 24-84 years) of patients who underwent MAG3-scintigraphy and contrast-enhanced abdominal CT within two weeks were retrospectively analyzed. Two independent readers assessed the CT-RCV in all CT datasets using a semi-automated volumetry tool. The MAG3-scintigraphy and CT-RCV methods were compared, stratified for the eGFR. Statistical analysis included descriptive statistics as well as inter- observer agreement. RESULTS: The absolute mean difference between the percentage contribution of the left and the right kidneys in total MAG3-clearance was 8.6%. Independent of eGFR, an overall sufficient agreement between both methods was established in all patients. A relatively small, tolerable systemic error resulted in an underestimation (max. 2%) of the left renal contribution to overall RCV. CONCLUSION: The results demonstrate that CT-RCV is a potential clinical replacement for MAG3-scintigraphy for calculation of SRF: CT-RCV demonstrates clinically tolerable differences with MAG3-scintigraphy, independent of patient eGFR. The relative complexity of the RCV method utilized is a potential limitation and may have contributed to the acceptable but only fair to moderate level of intra-reader reliability.

Focal Breast Lesions in Clinical CT Examinations of the Chest: A Retrospective Analysis.

Purpose Based on radiological reports, the percentage of breast cancers visualized as incidental findings in routine CT examinations is estimated at ≤ 2 %. In view of the rising number of CT examinations and the high prevalence of breast cancer, it was the goal of the present study to verify the frequency and image morphology of false-negative senological CT findings. Materials and Methods All first contrast-enhanced CT examinations of the chest in adult female patients carried out in 2012 were retrospectively included. A senior radiologist systematically assessed the presence of breast lesions on all CT images using the BI-RADS system. All BI-RADS ≥ 3 notations were evaluated by a second senior radiologist. A consensus was obtained in case of differing BI-RADS assessments. Reference diagnoses were elaborated based on all available clinical, radiological and pathological data. The findings of the CT reports were classified according to the BI-RADS system and were compared with the retrospective consensus findings as well as with the reference diagnoses. Results The range of indications comprised a broad spectrum including staging and follow-up examinations of solid tumors/lymphoma (N = 701, 59.9 %) and vascular (190, 16.2 %), inflammatory (48, 4.1 %) and pulmonologic (22, 1.9 %) issues. BI-RADS 1/2 classifications were present in 92.5 % and BI-RADS 6 classifications were assessed in 1.7 % of the 1170 included examinations. 68 patients (5.8 %) had at least one lesion retrospectively classified as BI-RADS 3 - 5. The histological potential was known in 57 of these lesions as benign (46, 3.9 %) or malignant (11, 0.9 %). 13 BI-RADS 4/5 consensus assessments (1.1 %) were false-positive. 2 of the 10 lesions classified as being malignant based on the further clinical and radiological course were not mentioned in the written CT reports (0.2 %). Both false-negative CT reports were therapeutically and prognostically irrelevant. Conclusion The relative frequency of BI-RADS 3 - 5 findings was 5.8 %. It reflects the situation encountered in clinical imaging for primarily non-senologic questions and therefore differs from what would be expected in a dedicated screening program. The rates of known false-positive BI-RADS 4/5 findings in the retrospective evaluations (1.1 %) and of false-negative findings in the written CT reports (0.2 %) reflect the different diagnostic approaches of image-based senological screening and radiological examinations indicated in order to solve clinical problems not primarily concerning the breast region. Statements regarding the prevalence of clinically occult breast cancers can only be made with caution in the presented, highly selective group of patients due to the often incomplete visualization of breast tissue and the retrospective approach. Key points · Intramammary mass and non-mass lesions needing clarification may be present in up to 5.8 % of all contrast enhanced CT-examinations of the female chest.. · Irregular forms, unscharp/spiculated margins, inhomogeneous matrices and a pronounced contrast medium enhancement point towards a malignant genesis of an intramammary mass or non-mass lesion.. · The results of the study highlight the importance of paying systematical and targeted attention on senological additional findings in CT-examinations of the chest also in other clinical settings than that of the included patients in a clinic with oncological main focus.. Zitierweise · Krug KB, Houbois C, Grinstein O et al. Focal Breast Lesions in Clinical CT Examinations of the Chest: A Retrospective Analysis. Fortschr Röntgenstr 2017; 189: 977 - 988.

Implementation of ultra-low-dose lung protocols in CT-guided lung biopsies: feasibility and safety in the clinical setting.

Objective To evaluate the use of ultra-low-dose computed tomography (ULDCT) for CT-guided lung biopsy versus standard-dose CT (SDCT). Methods CT-guided lung biopsies from 115 patients (50 ULDCT, 65 SDCT) were analyzed retrospectively. SDCT settings were 120 kVp with automatic mAs modulation. ULDCT settings were 80 kVp with fixed exposure (20 mAs). Two radiologists evaluated image quality (i.e., needle artifacts, lesion contouring, vessel recognition, visibility of interlobar fissures). Complications and histological results were also evaluated. Results ULDCT was considered feasible for all lung interventions, showing the same diagnostic accuracy as SDCT. Its mean total radiation dose (dose-length product) was significantly reduced to 34 mGy-cm (SDCT 426 mGy-cm). Image quality and complication rates ( P = 0.469) were consistent. Conclusions ULDCT for CT-guided lung biopsies appears safe and accurate, with a significantly reduced radiation dose. We therefore recommend routine clinical use of ULDCT for the benefit of patients and interventionalists.

ALKG1269A mutation as a potential mechanism of acquired resistance to crizotinib in an ALK-rearranged inflammatory myofibroblastic tumor.

Inflammatory myofibroblastic tumors are rare mesenchymal neoplasms frequently harboring oncogenic chromosomal rearrangements, most commonly, involving the ALK (anaplastic lymphoma kinase) gene. Treatment of this molecularly defined subgroup with the anaplastic lymphoma kinase inhibitor crizotinib has shown to be effective. However, comparable to lung adenocarcinoma, resistance inevitably develops. Second generation anaplastic lymphoma kinase inhibitors such as ceritinib are able to overcome acquired resistance to crizotinib. Here, we report the case of a patient with an inflammatory myofibroblastic tumors harboring a DCTN1-ALK fusion who developed resistance to crizotinib treatment. Next-generation sequencing of a rebiopsy sample revealed the acquisition of the ALKG1269A mutation as a mechanism of resistance. Therapy with ceritinib resulted in a short but profound clinical, metabolic and morphologic response. This case illustrates that (i) different tumor entities may share similar oncogenic driver mechanisms, rendering them vulnerable for the same therapeutic substances and (ii) likewise, the same mode of resistance may occur under targeted therapy among different tumor entities.

Automatic MDCT injectors: hygiene and efficiency of disposable, prefilled, and multidosing roller pump systems in clinical routine.

OBJECTIVE: This study evaluated three different injection systems with regard to microbiological contamination, time efficiency, and user handling during a clinical routine. SUBJECTS AND METHODS: A total of 825 patients were included. A double-syringe contrast injector with disposable syringes (system A; n = 150) and one that used prefilled syringes (system B; n = 150) were microbiologically analyzed during single use of the syringes in one patient. Moreover, the contamination of a roller pump injector capable of multidosing several patients from a contrast agent container, without the need for prior filling, was determined after being used for an entire day (system C; n = 35 injections/day for 15 days). The hygienic background was guaranteed by taking imprints of the surfaces of devices and the palms of the hands of members of CT staff before the clinical investigation. The time required for assembly of the injection systems and for filling or refilling of each injector system was measured. The handling of the three systems also was subjectively ranked by the technicians. RESULTS: Injection systems A, B, and C remained microbiologically sterile and free of contamination throughout their use in clinical routine. The mean (± SD) time for injection system assembly and installation of syringes and filling did not differ significantly between injection systems A and B (system A, 2.5 ± 1.1 minutes; system B, 1.9 ± 1.3 minutes; p = 0.12), whereas the time for assembly of system C was significantly shorter (0.9 ± 0.6 minutes; p < 0.05 vs system A; p < 0.05 vs system B). In the subjective ranking of injector handling, systems B and C were preferred. CONCLUSION: Double-syringe injectors used with disposable or prefilled contrast agent syringes, as well as roller pump injectors, ensure hygienic conditions in clinical routine. However, time efficiency and handling are aspects that favor prefilled and roller pump systems.

Usefulness of semi-automatic volumetry compared to established linear measurements in predicting lymph node metastases in MSCT.

BACKGROUND: Volumetry of lymph nodes potentially better reflect asymmetric size alterations independently of lymph node orientation in comparison to metric parameters (e.g. long-axis diameter). PURPOSE: To distinguish between benign and malignant lymph nodes by comparing 2D and semi-automatic 3D measurements in MSCT. MATERIAL AND METHODS: FDG-18 PET-CT was performed in 33 patients prior to therapy for malignant melanoma at stage III/IV. One hundred and eighty-six cervico-axillary, abdominal and inguinal lymph nodes were evaluated independently by two radiologists, both manually and with the use of semi-automatic segmentation software. Long axis (LAD), short axis (SAD), maximal 3D diameter, volume and elongation were obtained. PET-CT, PET-CT follow-up and/or histology served as a combined reference standard. Statistics encompassed intra-class correlation coefficients and ROC curves. RESULTS: Compared to manual assessment, semi-automatic inter-observer variability was found to be lower, e.g. at 2.4% (95% CI 0.05-4.8) for LAD. The standard of reference revealed metastases in 90 (48%) of 186 lymph nodes. Semi-automatic prediction of lymph node metastases revealed highest areas under the ROC curves for volume (reader 1 0.77, 95%CI 0.64-0.90; reader 2 0.76, 95%CI 0.59-0.86) and SAD (reader 1 0.76, 95%CI 0.64-0.88; reader 2 0.75, 95%CI 0.62-0.89). The findings for LAD (reader 1 0.73, 95%CI 0.60-0.86; reader 2 0.71, 95%CI 0.71, 95%CI 0.57-0.85) and maximal 3D diameter (reader 1 0.70, 95%CI 0.53-0.86; reader 2 0.76, 95%CI 0.50-0.80) were found substantially lower and for elongation (reader 1 0.65, 95%CI 0.50-0.79; reader 2 0.66, 95%CI 0.52-0.81) significantly lower (p < 0.05). CONCLUSION: Semi-automatic analysis of lymph nodes in malignant melanoma is supported by high segmentation quality and reproducibility. As compared to established SAD, semi-automatic lymph node volumetry does not have an additive role for categorizing lymph nodes as normal or metastatic in malignant melanoma.

Measurement accuracy and reproducibility of semiautomated metric and volumetric lymph node analysis in MDCT.

OBJECTIVE: The purpose of this study was to assess the measurement accuracy and reproducibility of semiautomated metric and volumetric lymph node analysis in MDCT. MATERIALS AND METHODS: Whole-body CT with IV contrast administration was performed on 112 patients. Peripheral (cervical, axillary, and inguinal), abdominal, and thoracic lymph nodes were evaluated independently by two radiologists both manually and with semiautomated segmentation software. Long-axis diameter, short-axis diameter, and volume were measured. Agreement between the semiautomated and manual measurements (measurement error), need for manual correction, and relative interobserver differences were determined. Statistical analysis encompassed the variance inhomogeneity test, intraclass correlation coefficients, and Bland-Altman plots. RESULTS: In total, 742 peripheral (cervical, axillary, and inguinal), abdominal, and thoracic lymph nodes (mean diameter, 13.2 ± 4.3 mm; range, 4-37 mm) were evaluated. Semiautomatic segmentation without need for further correction was possible for 480 of 742 lymph nodes (64.7%). Calculation of intraclass correlation coefficients revealed high correlation between manual and semiautomatic measurements (r = 0.70-0.81) with a slight trend toward size overestimation for semiautomatic short-axis diameter (14.3%; limits of agreement, -34.3%, 62.9%) and long-axis diameter (11.7%; limits of agreement, -25.2%, 48.5%). Bland-Altman plots showed significantly (p < 0.0001) lower interobserver differences for semiautomated short-axis diameter (1.2%; 95% CI, -39.9% to 42.3%) compared with the manual measurement (7.6%; 95% CI, -38.7% to 53.9%). Among all locations, the relative interobserver difference for semiautomatic volume (2.9%; 95% CI, -31.4% to 37.3%) was significantly lower than that for manual short-axis diameter (p < 0.0001), manual long-axis diameter (0.0178), and semiautomatic short-axis diameter (p < 0.0001). CONCLUSION: Semiautomatic short-axis diameter, particularly volume measurements, of lymph nodes are, irrespective of location, precise in terms of reproducibility and appear to be considerably more reliable than manual lymph node assessment.

Prediction of lymph node manifestations in malignant lymphoma: significant role of volumetric compared with established metric lymph node analysis in multislice computed tomography.

OBJECTIVE: Comparison of 2-dimensional and semiautomated 3-dimensional (3D) measurements to distinguish between benign and malignant lymph nodes in patients with malignant lymphoma. METHODS: Whole-body positron emission tomography-computed tomography (PET-CT) was performed in 33 patients before therapy for malignant lymphoma. Two hundred fifty-seven peripheral lymph nodes (mean size, 13.4 +/- 5.4 mm) were evaluated independently by 2 radiologists, both manually and with the use of semiautomated segmentation software. Long-axis diameter (LAD), short-axis diameter (SAD), maximal 3D diameter, volume, and elongation were measured. Positron emission tomography-CT and PET-CT follow-up and/or histology served as the reference standard. Statistical analysis encompassed intraclass correlation coefficients and receiver operating characteristic curves. RESULTS: The standard of reference revealed involvement in 116 (45%) of 257 lymph nodes. Manual and semiautomated LAD and SAD showed good correlation with intraclass coefficients of 0.85 and 0.72, respectively. Semiautomated prediction of malignant lymph nodes revealed the highest areas under the receiver operating characteristic curves for volume (0.760; 95% confidence interval [CI], 0.639-0.887) followed by SAD (0.740; 95% CI, 0.616-0.862). The findings for LAD (0.722; 95% CI, 0.588-0.855), maximal 3D diameter (0.697; 95% CI, 0.565-0.830), and lymph node elongation (0.605; 95% CI, 0.466-0.745) were significantly lower (P < 0.05). CONCLUSIONS: Volumetric lymph node analysis is significantly superior compared with established LAD in the prediction of lymph node involvement and therefore can add to the definition of peripheral lymphoma target lesions.

Microbiologic contamination and time efficiency of use of automatic MDCT injectors with prefilled syringes: Results of a clinical investigation.

OBJECTIVE: Multiple use of syringes in automatic injectors is considered to place patients at risk of septic complications. The purpose of this study was to evaluate the microbiologic contamination and time efficiency associated with routine clinical use of single-use prefilled disposable syringes for contrast administration. SUBJECTS AND METHODS: To ensure a hygienic background, imprints of devices and the palms of the hands of staff members were microbiologically analyzed before the clinical investigation. The microbiologic contamination of prefilled contrast and saline syringes was analyzed according to two protocols: single use of prefilled contrast syringes and saline syringes (n = 60) and single use of prefilled contrast syringes but multiple use of saline syringes for four injections or patients (n = 60). The time required for assembly of the injection system and filling and refilling for each protocol was measured. RESULTS: Contamination of the surfaces of devices and palms in the CT department was within the acceptable range for hygienic conditions. Prefilled disposable syringes for the contrast agent and saline solution used once had no microbiologic contamination. Microbial contamination with coagulase-negative staphylococci was found in two saline syringes used repeatedly. The time for assembly of the injection system and installation of prefilled syringes did not differ significantly (p = 0.45) between the single-use protocol (2.3 +/- 1.1 minutes) and the multiple-use protocol (2.0 +/- 1.4 minutes). CONCLUSION: Use of prefilled contrast syringes with single-use saline syringes is associated with time-efficient assembly of injection systems and prevents microbiologic contamination in clinical routine, especially in the care of immunocompromised patients.

Semiautomatic lymph node segmentation in multislice computed tomography: impact of slice thickness on segmentation quality, measurement precision, and interobserver variability.

OBJECTIVES: To determine the impact of slice thickness on semiautomatic lymph node analysis. MATERIALS AND METHODS: Thoracic multislice computed tomography (MSCT) of 46 patients with NSCLC were reconstructed at 1.0-, 3.0-, and 5.0-mm slice thickness. Two radiologists independently determined long and short axis diameter and volume of 299 thoracic lymph nodes by semiautomatic segmentation software. Necessity of manual correction (= relative difference between uncorrected and corrected segmented lymph node volume) and relative interobserver differences were determined. The precision of segmentation was expressed by relative measurement deviations (RMD) from the reference standard (mean of 1.0 mm datasets). Statistical analysis encompassed t test and Bland-Altman plots. RESULTS: Necessity of manual correction was significantly higher for 5.0 mm than for 3.0 (P = 0.042) or 1.0 mm (P = 0.0012). The RMD for long and short axis diameter were found to be independent of slice thickness, whereas the RMD for lymph node volume significantly (P = 0.021) increased from 4.0% at 1.0 mm (95% CI: 1.0%-3.5%) to 35% at 5.0 mm (95% CI: 10.5%-60.5%). The relative interobserver differences was consistently low for metric and volumetric parameters (eg, volume 2.3%, 95% CI: -7.4%-10.8% at 5.0 mm) with no difference in any of the slice thicknesses (P > 0.064). CONCLUSIONS: Significant deviations in lymph node volume together with excessive manual corrections suggest reconstruction of the data for semiautomatic lymph node assessment at a slice thickness of 1.0 mm but not exceeding 3.0 mm.

Introduction of an individually optimized protocol for the injection of contrast medium for coronary CT angiography.

The aim of this study was to determine whether individually tailored protocols for the injection of contrast medium (CM) result in higher and more homogeneous vascular attenuation throughout the coronary arteries at coronary CT angiography compared with conventional injection protocols using fixed injection parameters. Of 120 patients included in the study, 80 patients were randomized into two groups. Group 1 received 80 mL of CM at 6 mL/s. For group 2 injection parameters were individually adjusted to patient weight, the duration of CT data acquisition, and attenuation parameters following a test bolus. In the control group (group 3) the volume of CM was adjusted to the duration of CT data acquisition and injected at 5 mL/s. Attenuation was measured in the proximal, middle, and distal right coronary artery (RCA), in the proximal and middle left anterior descending artery (LAD), and in cranial and caudal sections of both ventricles. Patient parameters, scan delay, and scan duration did not differ significantly between the groups. Mean CM volume was 82.5 mL (flow rate 5.1 mL/s) in group 2 and 73.5 mL in group 3. Attenuation in both RCA and LAD was significantly higher for group 2 vs. group 3 (RCA: 414.9 + or - 49.9)-396.1(+ or - 52.1) HU vs. 366.0(+ or - 64.3)-341.6(+ or - 72.5) HU; LAD: 398.9(+ or - 48.6)-364.6(+ or - 44.6) HU vs. 356.3(+ or - 69.5)-323.0(+ or - 67.2) HU). For group 1 vs. group 2 only attenuation in the distal RCA differed significantly: 396.1(+ or - 52.1) vs. 370.7(+ or - 70.5) HU. Individually tailored CM injection protocols yield higher attenuation, especially in the distal segments of the coronary vessels, compared with injection protocols using fixed injection parameters.

Global left-ventricular function assessment using dual-source multidetector CT: effect of improved temporal resolution on ventricular volume measurement.

The purpose was to compare global left-ventricular (LV) function parameters measured with cine MRI with results from multiphase dual-source CT (DSCT) using 10 and 20 reconstruction phases. Twenty-eight patients with suspected or known CAD underwent DSCT coronary angiography. LV end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV), and ejection fraction (EF) were determined using LV segmentation and selection of specific phases from DSCT image sets reconstructed either at 5% or 10% steps through the R-R interval. Cine MRI served as the reference investigation. Threshold-based 3D-segmentation was feasible in all DSCT data sets. EDV and ESV were underestimated by DSCT, but showed excellent correlation (Pearson's correlation coefficient 0.95/0.97) to values obtained with MRI. Using data from 5% DSCT image reconstructions instead of 10% phase reconstructions, the position of the ED and ES phase was changed in 16 of 28 patients; ESVs were to found to be slightly smaller, whereas EDV were slightly larger, resulting in a systematic overestimation of LV EF by 1.9% (p=0.56). Threshold-based 3D segmentation enables accurate and reliable DSCT determination of global LV function with excellent correlation to cine MRI. Minor differences in LV EF indicate that both modalities are virtually interchangeable, even if the number of reconstructed phases is limited to 10% phase reconstructions.