Ultrahigh-Mass Resolution Mass Spectrometry Imaging with an Orbitrap Externally Coupled to a High-Performance Data Acquisition System

Matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging (MSI) is a powerful analytical tool that enables molecular sample analysis while simultaneously providing the spatial context of hundreds or even thousands of analytes. However, because of the lack of a separation step prior to ionization and the immense diversity of biomolecules, such as lipids, including numerous isobaric species, the coupling of ultrahigh mass resolution (UHR) with MSI presents one way in which this complexity can be resolved at the spectrum level. Until now, UHR MSI platforms have been restricted to Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers. Here, we demonstrate the capabilities of an Orbitrap-based UHR MSI platform to reach over 1,000,000 mass resolution in a lipid mass range (600-950 Da). Externally coupling the Orbitrap Q Exactive HF with the high-performance data acquisition system FTMS Booster X2 provided access to the unreduced data in the form of full-profile absorption-mode FT mass spectra. In addition, it allowed us to increase the time-domain transient length from 0.5 to 10 s, providing improvement in the mass resolution, signal-to-noise ratio, and mass accuracy. The resulting UHR performance generates high-quality MALDI MSI images and simplifies the identification of lipids. Collectively, these improvements resulted in a 1.5-fold increase in annotations, demonstrating the advantages of this UHR imaging platform for spatial lipidomics using MALDI-MSI.

Optimized protocol for MALDI MSI of N-glycans using an on-tissue digestion in fresh frozen tissue sections

Glycans play an important role in biology with multiple cellular functions ranging from cell signaling, mobility and growth to protein folding and localization. The N-glycosylation state within a tissue has been found to vary greatly between healthy and diseased patients and has proven to have an important clinical diagnostic value. Matrix assisted laser-desorption ionization (MALDI) mass spectrometry imaging (MSI) allows for untargeted analysis of biomolecules, including N-glycans, on a tissue section and provides a spatial context of the analyte. Until now, N-glycans have been predominantly analyzed using MALDI MSI on formalin-fixed paraffin embedded (FFPE) tissue sections, however this greatly reduces the clinical applicability, as the FFPE embedding process alters the biological environment of the tissue. Here we developed a protocol that allows for MALDI MSI of N-glycans from fresh frozen tissue that matches the current standard of FFPE analysis. By optimizing several steps in the sample preparation, we see orders of magnitude increase in signal intensity. Furthermore, this method limits delocalization of released N-glycans, thus improving the effective spatial resolution of the label-free molecular images. This protocol provides a novel perspective towards clinical application of MALDI MSI and capitalizes on the diagnostic value of N-glycan analysis.

MALDI-IHC-Guided In-Depth Spatial Proteomics: Targeted and Untargeted MSI Combined

Recently, a novel technology was published, utilizing the strengths of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) and immunohistochemistry (IHC), achieving highly multiplexed, targeted imaging of biomolecules in tissue. This new technique, called MALDI-IHC, opened up workflows to target molecules of interest using MALDI-MSI that are usually targeted by standard IHC. In this paper, the utility of targeted MALDI-IHC and its complementarity with untargeted on-tissue bottom-up spatial proteomics is explored using breast cancer tissue. Furthermore, the MALDI-2 effect was investigated and demonstrated to improve MALDI-IHC. Formalin-fixed paraffin-embedded (FFPE) human breast cancer tissue sections were stained for multiplex MALDI-IHC with six photocleavable mass-tagged (PC-MT) antibodies constituting a breast cancer antibody panel (CD20, actin-αSM, HER2, CD68, vimentin, and panCK). K-means spatial clusters were created based on the MALDI-IHC images and cut out using laser-capture microdissection (LMD) for further untargeted LC-MS-based bottom-up proteomics analyses. Numerous peptides could be tentatively assigned to multiple proteins, of which three proteins were also part of the antibody panel (vimentin, keratins, and actin). Post-ionization with MALDI-2 showed an increased intensity of the PC-MTs and suggests options for the development of new mass-tags. Although the on-tissue digestion covered a wider range of proteins, the MALDI-IHC allowed for easy and straightforward identification of proteins that were not detected in untargeted approaches. The combination of the multiplexed MALDI-IHC with image-guided proteomics showed great potential to further investigate diseases by providing complementary information from the same tissue section and without the need for customized instrumentation.

Nuklearmedizin in Deutschland

Aim: To explain the spectrum and number of in-vivo nuclear medicine examinations and therapies based on official statistics about out-patient and in-patient care. Trends in time of the frequency and spectrum of procedures as well as data on the health care structure for nuclear medicine in Germany should be collected. Methods: Data from the Gesundheitsberichterstattung des Bundes, from the frequency statistics of the statutory health insurance for out-patients and from the Bundes - ärztekammer were used. Customized queries were performed to analyse temporal changes. Results: Nuclear medicine physicians are more frequently consulted by out-patients over the last years (2008: 2 024 498; 2009: 2 164 664) and the number of colleagues in private practice increased. For in-patients, the frequency of conventional nuclear medicine procedures (mainly for brain, lymphatic system, lung and heart) increased since 2008 after a decline in previous years (2009: 323 515; +4.6%) and the number of PET(/CT) examinations continued to rise (2009: 25 123; +18%), even if changes in OPS keys may hamper comparisons. Nearly 600 gamma cameras and 76 PET(/CT) scanners were installed in hospitals in 2008. Nuclear medicine procedures are increasingly performed as cross sectional imaging like SPECT(/CT) and PET(/CT). With the supply shortfall with 99Mo, the frequency of thyroid scans with 123I iodine increased as well as the use of 18F PET as a substitute for conventional bone scans. The number of radionuclide therapies, in particular non-thyroid treatments, increased since the mid-nineties and stabilized at nearly 50 000 cases per year with shorter lengths of stay. Conclusion: The details of the present analysis may help to understand the positive evolution of key numbers for nuclear medicine.

[Chronic thromboembolic pulmonary hypertension: Recommendations of the Cologne Consensus Conference 2016]

The 2015 European Guidelines on Pulmonary Hypertension did not cover only pulmonary arterial hypertension (PAH), but also other significant subgroups of pulmonary hypertension (PH). In June 2016, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany to discuss open and controversial issues surrounding the practical implementation of the European Guidelines. Several working groups were initiated, one of which was dedicated to the diagnosis and treatment of chronic thromboembolic pulmonary hypertension (CTEPH). In every patient with PH of unknown cause CTEPH should be excluded. The primary treatment option is surgical pulmonary endarterectomy (PEA) in a specialized multidisciplinary CTEPH center. Inoperable patients or patients with persistent or recurrent CTEPH after PEA are candidates for targeted drug therapy. For balloon pulmonary angioplasty (BPA), there is currently only limited experience. This option - as PEA - is reserved to specialized centers with expertise for this treatment method. In addition, a brief overview is given on pulmonary artery sarcoma, since its surgical treatment is often analogous to PEA. The recommendations of this working group are summarized in the present paper.

Integration of FDG-PET/CT into external beam radiation therapy planning: technical aspects and recommendations on methodological approaches

This work addresses the clinical adoption of FDG-PET/CT for image-guided radiation therapy planning (RTP). As such, important technical and methodological aspects of PET/CT-based RTP are reviewed and practical recommendations are given for routine patient management and clinical studies. First, recent developments in PET/CT hardware that are relevant to RTP are reviewed in the context of quality control and system calibration procedures that are mandatory for a reproducible adoption of PET/CT in RTP. Second, recommendations are provided on image acquisition and reconstruction to support the standardization of imaging protocols. A major prerequisite for routine RTP is a complete and secure data transfer to the actual planning system. Third, state-of-the-art tools for image fusion and co-registration are discussed briefly in the context of PET/CT imaging pre- and post-RTP. This includes a brief review of state-of-the-art image contouring algorithms relevant to PET/CT-guided RTP. Finally, practical aspects of clinical workflow and patient management, such as patient setup and requirements for staff training are emphasized. PET/CT-guided RTP mandates attention to logistical aspects, patient set-up and acquisition parameters as well as an in-depth appreciation of quality control and protocol standardization.

CONCLUSION

Upon fulfilling the requirements to perform PET/CT for RTP, a new dimension of molecular imaging can be added to traditional morphological imaging. As a consequence, PET/CT imaging will support improved RTP and better patient care. This document serves as a guidance on practical and clinically validated instructions that are deemed useful to the staff involved in PET/CT-guided RTP.

Multi-centre calibration of an adaptive thresholding method for PET-based delineation of tumour volumes in radiotherapy planning of lung cancer

PURPOSE

To evaluate the calibration of an adaptive thresholding algorithm (contrast-oriented algorithm) for FDG PET-based delineation of tumour volumes in eleven centres with respect to scanner types and image data processing by phantom measurements.

METHODS

A cylindrical phantom with spheres of different diameters was filled with FDG realizing different signal-to-background ratios and scanned using 5 Siemens Biograph PET/CT scanners, 5 Philips Gemini PET/CT scanners, and one Siemens ECAT-ART PET scanner. All scans were analysed by the contrast-oriented algorithm implemented in two different software packages. For each site, the threshold SUVs of all spheres best matching the known sphere volumes were determined. Calibration parameters a and b were calculated for each combination of scanner and image-analysis software package. In addition, "scanner-type-specific" calibration curves were determined from all values obtained for each combination of scanner type and software package. Both kinds of calibration curves were used for volume delineation of the spheres.

RESULTS

Only minor differences in calibration parameters were observed for scanners of the same type (Δa ≤4%, Δb ≤14%) provided that identical imaging protocols were used whereas significant differences were found comparing calibration parameters of the ART scanner with those of scanners of different type (Δa ≤60%, Δb ≤54%). After calibration, for all scanners investigated the calculated SUV thresholds for auto-contouring did not differ significantly (all p>0.58). The resulting sphere volumes deviated by less than -7% to +8% from the true values.

CONCLUSION

After multi-centre calibration the use of the contrast-oriented algorithm for FDG PET-based delineation of tumour volumes in the different centres using different scanner types and specific imaging protocols is feasible.

Retrospective web-based multicenter evaluation of ¹⁸F-FDG-PET and CT derived predictive factors. Radioimmunotherapy with yttrium-90-ibritumomab tiuxetan in follicular non Hodgkin's lymphoma

AIM

Although predictive factors (PF) for conventional lymphoma therapy are established and frequently used in clinical practice and medical research, the PF for radioimmunotherapy (RIT) have not been fully defined until now. The aim of this multicenter evaluation is to prove the feasibility of the multicenter web-based data collection and to preliminary explore imaging findings and prediction of therapy response in patients with follicular lymphoma (FL) following radioimmunotherapy (RIT) with 90Y-ibritumomab tiuxetan.

PATIENTS, METHODS

We retrospectively analyzed and correlated clinical and imaging data (CT and FDG-PET) before and after RIT as documented by the RIT-Network. Evaluation of treatment response was done on both patient and lesion basis. Every measurable lesion was analyzed in terms of standardized uptake value (SUV), volume (CT and PET) and response. PF were identified using a uni- and multivariate model. A web-based system was used for the documentation and evaluation of clinical and imaging data.

RESULTS

16 patients with at least one PET before and after RIT were eligible for analysis. Concerning response three months postRIT, 5 patients achieved a CR, 6 patients a PR and 4 patients remained with NC. A total of 159 lesions were measured (mean 10±8). In the multivariate model the log lesion volume (p < 0.0001), the total (p = 0.03) and maximum lesion volume (p = 0.05) were predictors for response (CR + PR). Concerning the lesional CR initial small lesion volume (p = 0.009) and its high metabolic activity (p = 0.01) were identified as predictors. The web-based system showed no major disturbances allowing secure data transfer and central image interpretation in a reasonable time.

CONCLUSION

The use of a web-based multicenter archiving system for clinical and imaging data is technically feasible in a multicenter setting and allows a central analysis. This preliminary analysis suggests that FDG-PET may predict the likelihood of response to RIT.

[Imaging diagnostics of the pharynx and larynx]

The pharynx and larynx represent very sophisticated regions and may be involved in a diverse range of pathologic conditions. Evaluation of the head and neck has developed significantly with the establishment of CT and MRI as they provide true insights into the endoscopically blind areas as well as depth of tumor infiltration, its submucosal growth and contralateral involvement, cartilage invasion, bone marrow invasion, and nonpalpable adenopathy. Inflammations in the head and neck region are only exceptionally imaged with CT or MRI; indications are the diagnosis of retrotonsillar and parapharyngeal abscesses and ensuing complications. The different imaging modalities of malignant pharyngeal and laryngeal tumors and their differential diagnosis are presented in this paper.

Regional services for children and youth with diabetes

A regional diabetes program for children and youth comprising outreach clinics, frequent routine and emergency telephone contact, and a camping program was developed within the State Children's Medical Services (Crippled Children's) Program. The pediatric nurse specialist in diabetes served as the pivotal professional in the education and supervision of patients. Cost benefit was calculated from estimated hospital days prevented based on average length of admissions at diagnosis (14 days) and hospital days in the year prior to referral of those with established diabetes. During the first year 369 hospital days were prevented, for an estimated savings of $65,000; the second year 547 hospital days were avoided, a value of $96,000. Total annual program costs to the state and private patients (including camp fees) were $36,000. Although hospital costs are an apparent and useful reference to justify funding, the main value of the program must be in the prevention of secondary physical and emotional disability. This requires continuous commitment and availability of persons who know the patient and family, who can interpret information related to metabolic control of diabetes, and who are able to influence the family and community to respond appropriately to the youngster's needs.

The role of urine sugar in diabetic management

The concentration of reducing sugar in the urine is commonly used in the management of diabetes in children. Supplemental doses of regular insulin are administered in response to the concentration of urine sugar according to a protocol termed the "sliding scale." This practice assumes that the concentration of sugar in urine is a good indicator of the plasma glucose concentration. This assumption was tested by comparing urine sugar concentrations in first and second voided urines with the plasma glucose concentrations in 220 children with diabetes. The correlation was good (r = .92) for both the first and second voided urine specimens. Thus, urine sugar concentrations in general define the level of plasma glucose. The large standard deviation of the plasma glucose at each concentration of urine sugar, however, limits the usefulness of urine sugar as an accurate reflection of the coincident plasma glucose concentration. The urine sugar concentration, although useful for the general management of diabetes, provides significant risk when used to guide frequent adjustments in insulin administration. Therefore, the "sliding scale" should not be used in the treatment of children with diabetes.

Good diabetic control - a study in mass delusion

The terms "diabetic control" and "diabetic management" are not synonymous. Diabetic control implies normal glucose metabolism, typically monitored by periodic determinations of plasma glucose and urine reducing sugar concentrations. A group of 220 diabetic children attending a camp complied 74% of the time with the request to collect and test their urine for URS. Fifty percent of random URS values determined by the children varied from those obtained on the same specimens of urine by laboratory technicians. Good diabetic control defined URS less than 25gm/24 hours was found in 18 of 54 children.

Joint contracture--common manifestation of childhood diabetes mellitus

Sixty-five of 229 seven to eighteen-year-old campers with diabetes were found to have contractures of finger joints; in two thirds of affected children only the fifth finger was involved. Stiff resistance to passive finger manipulation and thickened adherent skin over the dorsa of the hands were additional features. Short stature was associated with involvement of more than one finger; the shortest youngsters also had contractures of large joints. Joint changes were independent of age, sex, age of onset of diabetes, and control of diabetes, but correlated with duration of the diabetes.

Age-adjusted analysis of insulin responses during normal and abnormal glucose tolerance tests in children and adolescents

This report analyzes age-specific glucose (PG) and immunoassayable insulin (IRI) responses during oral glucose tolerance testing (OGTT) and examines test results in children and adolescents with OGTT abnormality using the age-appropriate control data. Controls' (n = 93) and patients' (n = 63) results were compared on the basis of statural age (SA) at the time of testing. Control tests (n = 101) showed significant positive correlation of fasting and four-hour postingestion PG with SA (p less than 0.001), but mean area under the PG curves did not vary between the SA groups (I--18.69 months, II--70-131 months, III--132+ months). The absence of differences of other sampling times permits uniform diagnostic criteria for this age group. IRI was positively correlated with SA at all testing times, and mean levels differed significantly between each SA group at every sampling time; the mean areas under the IRI curve also differed significantly between SA groups as did the mean ratios of IRI area to PG area (group I--0.2639 +/- 0.0175 S.E.M., group II--0.3864 +/- 0.0235, group III--0.6262 +/-0.0491). Patient tests (n = 110) were separated into normal (N), borderline (B), and chemical-diabetic (C) for each SA group. IRI means were above control data for each test type in each SA group at all sampling times; one fourth of these differences were significant. IRI responses also increased within each SA group from N to B to C tests. Mean IRI areas and IRI area to PG are mean ratios were higher than in controls, and this difference was greatest with the most abnormal (C) test type in each SA group. A subgroup of three patients who had low IRI responses from the outset and developed overt diabetes in one to three years was excluded from the analysis. In contrast to apparent relative insulin inefficiency with normal maturation and with chemical diabetes, they had exceptional responsiveness to their low IRI levels. Variable involvement of alpha as well as beta cells in the pathophysiology of diabetes is suggested as one explanation for these paradoxic observations. Changing receptor affinity might also be implicated.