On the cortical connectivity in the macaque brain: A comparison of diffusion tractography and histological tracing data.

Diffusion-weighted magnetic resonance imaging (DW-MRI) tractography is a non-invasive tool to probe neural connections and the structure of the white matter. It has been applied successfully in studies of neurological disorders and normal connectivity. Recent work has revealed that tractography produces a high incidence of false-positive connections, often from "bottleneck" white matter configurations. The rich literature in histological connectivity analysis studies in the macaque monkey enables quantitative evaluation of the performance of tractography algorithms. In this study, we use the intricate connections of frontal, cingulate, and parietal areas, well established by the anatomical literature, to derive a symmetrical histological connectivity matrix composed of 59 cortical areas. We evaluate the performance of fifteen diffusion tractography algorithms, including global, deterministic, and probabilistic state-of-the-art methods for the connectivity predictions of 1711 distinct pairs of areas, among which 680 are reported connected by the literature. The diffusion connectivity analysis was performed on a different ex-vivo macaque brain, acquired using multi-shell DW-MRI protocol, at high spatial and angular resolutions. Across all tested algorithms, the true-positive and true-negative connections were dominant over false-positive and false-negative connections, respectively. Moreover, three-quarters of streamlines had endpoints location in agreement with histological data, on average. Furthermore, probabilistic streamline tractography algorithms show the best performances in predicting which areas are connected. Altogether, we propose a method for quantitative evaluation of tractography algorithms, which aims at improving the sensitivity and the specificity of diffusion-based connectivity analysis. Overall, those results confirm the usefulness of tractography in predicting connectivity, although errors are produced. Many of the errors result from bottleneck white matter configurations near the cortical grey matter and should be the target of future implementation of methods.

Comparison of line-field confocal optical coherence tomography images with histological sections: Validation of a new method for in vivo and non-invasive quantification of superficial dermis thickness.

BACKGROUND: Line-field confocal optical coherence tomography (LC-OCT) is an imaging technique providing "optical biopsies" of the skin in real time and non-invasively. At a center optical wavelength of 1.3 µm, this innovative technology can be applied to dermo-cosmetic product development due to both high image resolution (~2 µm) and sufficient penetration (~0.5 mm). Nevertheless, the precise dermal area analyzed with LC-OCT has never been identified. In this study, the objective was to compare LC-OCT images with histological sections of the same area, in order to validate a new method for in vivo and non-invasive quantification of superficial dermis thickness. Once validated, this standardized and quantitative method was used to assess age-related changes of the superficial dermis. MATERIALS AND METHODS: Ex vivo LC-OCT acquisitions and hematoxylin-eosin-safran staining were performed on a panel of four healthy Caucasian female volunteers. In vivo LC-OCT study of skin aging was performed on a panel of 37 healthy Caucasian female divided into five different age-groups. RESULTS: Comparison with histological sections revealed that LC-OCT images allow the visualization and the quantification of the superficial portion of papillary dermis. Applied to different age-group of volunteers, LC-OCT images show a constant decrease in this superficial dermis thickness with age. CONCLUSIONS: In conclusion, we have introduced LC-OCT as a novel technique for in vivo and non-invasive evaluation of superficial dermis thickness. This approach could be used in the future to demonstrate visually and quantitatively the capacity of a dermo-cosmetic active ingredient to renormalize the structural properties of the dermis.

Examination of total hip and knee arthroplasty tissues.

BACKGROUND: Many practices require tissues from hip and knee arthroplasty procedures to be sent for pathologic examination. These examinations rarely provide information beyond the clinical or radiologic diagnosis and rarely alter clinical management. We aimed to determine the rate at which histologic diagnoses based on gross assessment alone or gross plus microscopic assessment correspond with reported clinical diagnoses in patients undergoing total joint arthroplasties and whether the histologic diagnoses alter patient management. METHODS: We retrospectively reviewed arthroplasty cases performed at a high-volume teaching hospital in Manitoba, Canada. The clinical diagnosis was compared with the final pathology report based on gross examination, with or without histologic assessment. The results of the comparison were classified into 3 categories: concordant (same diagnosis), discrepant (different diagnoses without alterations in management) and discordant (different diagnoses resulting in management change). The overall provincial cost for pathologic examination was determined by multiplying the total examination cost by the estimated number of arthroplasty cases. RESULTS: There were 773 patients in our study sample. The concordant rate was 98.3% (95% confidence interval [CI] 97.1%-99.1%), the discrepant rate was 1.7% (95% CI 0.9%-2.9%) and the discordant rate was 0.0% (95% CI 0%-0.5%) for 773 cases. The pathology diagnosis did not alter patient management in any case. A total of 91.5% of specimens did not require full histologic review and received gross descriptions only. The discrepancy rate was higher in cases that included microscopic examination than in those that received only gross descriptions (15.2% v. 0.4%, p < 0.001). The overall provincial cost for pathologic examination was estimated at Can$304 556. CONCLUSION: Submitting routine tissue from arthroplasty procedures to pathology does not affect patient management and therefore provides no value for the health care resources expended in doing so.

CONTEXTE: Beaucoup d'établissements exigent que des tissus soient envoyés pour un examen anatomopathologique après une arthroplastie de la hanche et du genou. Ces examens n'apportent généralement pas d'information nouvelle quant au diagnostic clinique ou radiologique et modifient rarement la prise en charge. Notre objectif était de déterminer le pourcentage de correspondance entre les diagnostics histologiques fondés sur l'inspection grossière uniquement ou sur l'inspection grossière et l'examen au microscope, et les diagnostics cliniques des patients qui subissent des arthroplasties totales. Nous cherchions également à savoir si les diagnostics histologiques modifient la prise en charge. MÉTHODES: Nous avons procédé à une analyse rétrospective d'arthroplasties effectuées dans un grand hôpital universitaire du Manitoba, au Canada. Le diagnostic clinique était comparé au rapport final de pathologie fondé sur une inspection grossière, avec ou sans examen histologique. Les résultats de cette comparaison étaient classés en 3 catégories : concordance (même diagnostic), divergence (diagnostics différents, sans modification de la prise en charge) et discordance (diagnostics différents entraînant une modification de la prise en charge). Le coût global pour la province associé aux examens pathologiques a été établi en multipliant le coût total d'un examen par le nombre estimé de cas d'arthroplastie. RÉSULTATS: Notre échantillon comprenait 773 patients. Le taux de concordance était de 98,3 % (intervalle de confiance [IC] de 95 % 97,1 %­99,1 %), le taux de divergence était de 1,7 % (IC de 95 % 0,9 %­2,9 %) et le taux de discordance de 0,0 % (IC de 95 % 0 %­0,5 %). Dans tous les cas, le diagnostic pathologique n'a pas modifié la prise en charge. Au total, 91,5 % des spécimens ne nécessitaient pas d'examen histologique complet et n'ont fait l'objet que d'une inspection grossière. Le pourcentage d'anomalie était plus élevé pour les spécimens analysés au microscope que pour ceux ayant uniquement subi une inspection grossière (15,2 % c. 0,4 %, p < 0,001). Le coût total des examens pathologiques pour la province a été estimé à 304 556 $ CA. CONCLUSION: L'analyse pathologique systématique de tissus prélevés lors d'arthroplasties n'entraîne pas une modification de la prise en charge du patient; il n'y a donc pas de valeur associée aux ressources de santé utilisées pour ces examens.

An Overview on the Considerations for the Planning of Nonclinical Necropsies for Medical Device Studies.

The terminal collection and histological processing of medical devices is an expensive, labor-, and material-intensive endeavor, which requires adequate experience, innovation, and preparation for success. It is also an exciting endeavor that continually challenges, intellectually engages, and improves the skills and knowledge of the pathologist. Awareness of the importance of the medical device pathologist's involvement, communication, and oversight throughout the development, implementation, and execution of a nonclinical assessment of a medical device is in the best interest of the test facility, the histopathology laboratory, the pathologist, the sponsor, and, ultimately, the patients. This article serves to present as a primer of key considerations for the approach and conduct of "nontoxicological" studies, defined as studies involving animal models of deployment or implantation of medical devices as well as surgical animal models.

Introduction to Currently Applied Device Pathology.

Pathologic evaluation is crucial to the study of medical devices and integral to the Food and Drug Administration and other regulatory entities' assessment of device safety and efficacy. While pathologic analysis is tailored to the type of device, it generally involves at a minimum gross and microscopic evaluation of the medical device and associated tissues. Due to the complex nature of some implanted devices and specific questions posed by sponsors, pathologic evaluation inherently presents many challenges in accurately assessing medical device safety and efficacy. This laboratory's experience in numerous collaborative projects involving veterinary pathologists, biomedical engineers, physicians, and other scientists has led to a set of interrelated assessments to determine pathologic end points as a means to address these challenges and achieve study outcomes. Thorough device evaluation is often accomplished by utilizing traditional paraffin histology, plastic embedding and microground sections, and advanced imaging modalities. Combining these advanced techniques provides an integrative, comprehensive approach to medical device pathology and enhances medical device safety and efficacy assessment.

Performance of Anal Cytology Compared With High-Resolution Anoscopy and Histology in Women With Lower Anogenital Tract Neoplasia.

Background: Information on the performance of anal cytology in women who are high risk for human papillomavirus-related lesions and the factors that might influence cytology are largely lacking. Methods: Retrospective study including all new referrals of women with a previous history of anogenital neoplasia from January 2012 to July 2017, with concomitant anal cytology and high-resolution anoscopy with or without biopsies. Results: Six hundred and thirty six anal cytology samples and 323 biopsies obtained from 278 women were included. Overall sensitivity and specificity of "any abnormality" on anal cytology to predict any abnormality in histology was 47% (95% confidence interval [CI], 41%-54%) and 84% (95% CI, 73%-91%), respectively. For detecting high-grade squamous intraepithelial lesions (HSIL)/cancer, sensitivity was 71% (95% CI, 61%-79%) and specificity was 73% (95% CI, 66%-79%). There was a poor concordance between cytological and histological grades (κ = 0.147). Cytology had a higher sensitivity to predict HSIL/cancer in immunosuppressed vs nonimmunosuppressed patients (92% vs 60%, P = .002). The sensitivity for HSIL detection was higher when 2 or more quadrants were affected compared with 1 (86% vs 57%, P = .006). A previous history of vulvar HSIL/cancer (odds ratio [OR], 1.71, 1.08-2.73; P = .023), immunosuppression (OR, 1.88, 1.17-3.03; P = .009), and concomitant genital HSIL/cancer (OR, 2.51, 1.47-4.29; P = .001) were risk factors for abnormal cytology. Conclusions: Women characteristics can influence the performance of anal cytology. The sensitivity for detecting anal HSIL/cancer was higher in those immunosuppressed and with more extensive disease.

Regulatory Forum Opinion Piece*: Effective Brain Trimming for Regulatory-type Nonclinical Toxicity Studies.

Regulatory guidances for nonclinical toxicity testing require brain evaluation but do not require a specific analytical strategy. The Society of Toxicologic Pathology (STP) has produced "best practice" recommendations for brain sampling and processing in general toxicity (GT) studies in adult rodents and nonrodents as well as developmental neurotoxicity (DNT) studies in rodents. This article explains acceptable brain trimming strategies as described in these 2 STP documents. Figures in the DNT and GT "best practices" illustrate coronal brain trimming at specific levels as defined by discrete external and internal anatomic landmarks. However, the text of both "best practice" papers states that institutions may choose different brain trimming levels or other planes (e.g., a longitudinal orientation) as long as key structures are sampled and trimming is consistent among individuals across the study. The STP-recommended number of brain levels to evaluate (7 or 8 coronal sections for GT and DNT studies, respectively) may need to be increased if neurotoxicity is considered possible or likely based on in-life clinical findings or other risk factors (chemical structure, known mode of action, etc.).

STP Position Paper: Recommended Best Practices for Sampling, Processing, and Analysis of the Peripheral Nervous System (Nerves and Somatic and Autonomic Ganglia) during Nonclinical Toxicity Studies.

Peripheral nervous system (PNS) toxicity is surveyed inconsistently in nonclinical general toxicity studies. These Society of Toxicologic Pathology "best practice" recommendations are designed to ensure consistent, efficient, and effective sampling, processing, and evaluation of PNS tissues for four different situations encountered during nonclinical general toxicity (screening) and dedicated neurotoxicity studies. For toxicity studies where neurotoxicity is unknown or not anticipated (situation 1), PNS evaluation may be limited to one sensorimotor spinal nerve. If somatic PNS neurotoxicity is suspected (situation 2), analysis minimally should include three spinal nerves, multiple dorsal root ganglia, and a trigeminal ganglion. If autonomic PNS neuropathy is suspected (situation 3), parasympathetic and sympathetic ganglia should be assessed. For dedicated neurotoxicity studies where a neurotoxic effect is expected (situation 4), PNS sampling follows the strategy for situations 2 and/or 3, as dictated by functional or other compound/target-specific data. For all situations, bilateral sampling with unilateral processing is acceptable. For situations 1-3, PNS is processed conventionally (immersion in buffered formalin, paraffin embedding, and hematoxylin and eosin staining). For situation 4 (and situations 2 and 3 if resources and timing permit), perfusion fixation with methanol-free fixative is recommended. Where PNS neurotoxicity is suspected or likely, at least one (situations 2 and 3) or two (situation 4) nerve cross sections should be postfixed with glutaraldehyde and osmium before hard plastic resin embedding; soft plastic embedding is not a suitable substitute for hard plastic. Special methods may be used if warranted to further characterize PNS findings. Initial PNS analysis should be informed, not masked ("blinded"). Institutions may adapt these recommendations to fit their specific programmatic requirements but may need to explain in project documentation the rationale for their chosen PNS sampling, processing, and evaluation strategy.

Optimizing CLEM protocols for plants cells: GMA embedding and cryosections as alternatives for preservation of GFP fluorescence in Arabidopsis roots.

Recently, a number of diverse correlative light and electron microscopy (CLEM) protocols have been developed for several model organisms. However, these CLEM methods have largely bypassed plant cell research, with most protocols having little application to plants. Using autophagosome identification as a biological background, we propose and compare two CLEM protocols that can be performed in most plant research laboratories, providing a good compromise that preserves fluorescent signals as well as ultrastructural features. These protocols are based on either the adaptation of a high pressure fixation/GMA acrylic resin embedding method, or on the Tokuyasu approach. Both protocols suitably preserved GFP fluorescence while allowing the observation of cell ultrastructure in plants. Finally, the advantages and disadvantages of these protocols are discussed in the context of multiscale imaging of plant cells.

Evaluating fibre orientation dispersion in white matter: Comparison of diffusion MRI, histology and polarized light imaging.

Diffusion MRI is an exquisitely sensitive probe of tissue microstructure, and is currently the only non-invasive measure of the brain's fibre architecture. As this technique becomes more sophisticated and microstructurally informative, there is increasing value in comparing diffusion MRI with microscopic imaging in the same tissue samples. This study compared estimates of fibre orientation dispersion in white matter derived from diffusion MRI to reference measures of dispersion obtained from polarized light imaging and histology. Three post-mortem brain specimens were scanned with diffusion MRI and analyzed with a two-compartment dispersion model. The specimens were then sectioned for microscopy, including polarized light imaging estimates of fibre orientation and histological quantitative estimates of myelin and astrocytes. Dispersion estimates were correlated on region - and voxel-wise levels in the corpus callosum, the centrum semiovale and the corticospinal tract. The region-wise analysis yielded correlation coefficients of r = 0.79 for the diffusion MRI and histology comparison, while r = 0.60 was reported for the comparison with polarized light imaging. In the corpus callosum, we observed a pattern of higher dispersion at the midline compared to its lateral aspects. This pattern was present in all modalities and the dispersion profiles from microscopy and diffusion MRI were highly correlated. The astrocytes appeared to have minor contribution to dispersion observed with diffusion MRI. These results demonstrate that fibre orientation dispersion estimates from diffusion MRI represents the tissue architecture well. Dispersion models might be improved by more faithfully incorporating an informed mapping based on microscopy data.

The peri-esophageal connective tissue layers and related compartments: visualization by histology and magnetic resonance imaging.

An organized layer of connective tissue coursing from aorta to esophagus was recently discovered in the mediastinum. The relations with other peri-esophageal fascias have not been described and it is unclear whether this layer can be visualized by non-invasive imaging. This study aimed to provide a comprehensive description of the peri-esophageal fascias and determine whether the connective tissue layer between aorta and esophagus can be visualized by magnetic resonance imaging (MRI). First, T2-weighted MRI scanning of the thoracic region of a human cadaver was performed, followed by histological examination of transverse sections of the peri-esophageal tissue between the thyroid gland and the diaphragm. Secondly, pretreatment motion-triggered MRI scans were prospectively obtained from 34 patients with esophageal cancer and independently assessed by two radiologists for the presence and location of the connective tissue layer coursing from aorta to esophagus. A layer of connective tissue coursing from the anterior aspect of the descending aorta to the left lateral aspect of the esophagus, with a thin extension coursing to the right pleural reflection, was visualized ex vivo in the cadaver on MR images, macroscopic tissue sections, and after histologic staining, as well as on in vivo MR images. The layer connecting esophagus and aorta was named 'aorto-esophageal ligament' and the layer connecting aorta to the right pleural reflection 'aorto-pleural ligament'. These connective tissue layers divides the posterior mediastinum in an anterior compartment containing the esophagus, (carinal) lymph nodes and vagus nerve, and a posterior compartment, containing the azygos vein, thoracic duct and occasionally lymph nodes. The anterior compartment was named 'peri-esophageal compartment' and the posterior compartment 'para-aortic compartment'. The connective tissue layers superior to the aortic arch and at the diaphragm corresponded with the currently available anatomic descriptions. This study confirms the existence of the previously described connective tissue layer coursing from aorta to esophagus, challenging the long-standing paradigm that no such structure exists. A comprehensive, detailed description of the peri-esophageal fascias is provided and, furthermore, it is shown that the connective tissue layer coursing from aorta to esophagus can be visualized in vivo by MRI.

Pitfalls and major issues in the histologic diagnosis of peripheral T-cell lymphomas: results of the central review of 573 cases from the T-Cell Project, an international, cooperative study.

Peripheral T-cell lymphomas (PTCLs) comprise a heterogeneous group of neoplasms that are derived from post-thymic lymphoid cells at different stages of differentiation with different morphological patterns, phenotypes and clinical presentations. PTCLs are highly diverse, reflecting the diverse cells from which they can originate and are currently sub-classified using World Health Organization (WHO) 2008 criteria. In 2006 the International T-Cell Lymphoma Project launched the T-Cell Project, building on the retrospective study previously carried on by the network, with the aim to prospectively collect accurate data to improve knowledge on this group of lymphomas. Based on previously published reports from International Study Groups it emerged that rendering a correct classification of PTCLs is quite difficult because the relatively low prevalence of these diseases results in a lack of confidence by most pathologists. This is the reason why the T-Cell Project requested the availability of diagnostic material from the initial biopsy of each patient registered in the study in order to have the initial diagnosis centrally reviewed by expert hematopathologists. In the present report the results of the review process performed on 573 cases are presented. Overall, an incorrect diagnosis was centrally recorded in 13.1% cases, including 8.5% cases centrally reclassified with a subtype eligible for the project and 4.6% cases misclassified and found to be disorders other than T-cell lymphomas; 2.1% cases were centrally classified as T-Cell disorders not included in the study population. Thus, the T-Cell Project confirmed the difficulties in providing an accurate classification when a diagnosis of PTCLs is suspected, singled out the major pitfalls that can bias a correct histologic categorization and confirmed that a centralized expert review with the application of adequate diagnostic algorithms is mandatory when dealing with these tumours. Copyright © 2016 John Wiley & Sons, Ltd.

Histologic scoring indices for evaluation of disease activity in Crohn's disease.

BACKGROUND: Histologic assessment of mucosal disease activity has been increasingly used in clinical trials of treatment for Crohn's disease. However, the operating properties of the currently existing histologic scoring indices remain unclear. OBJECTIVES: A systematic review was undertaken to evaluate the development and operating characteristics of available histologic disease activity indices in Crohn's disease. SEARCH METHODS: Electronic searches of MEDLINE, EMBASE, PubMed, and the Cochrane Library (CENTRAL) databases from inception to 20 July 2016 were supplemented by manual reviews of bibliographies and abstracts submitted to major gastroenterology meetings (Digestive Disease Week, United European Gastroenterology Week, European Crohn's and Colitis Organisation). SELECTION CRITERIA: Any study design (e.g. randomised controlled trial, cohort study, case series) that evaluated a histologic disease activity index in patients with Crohn's disease was considered for inclusion. Study participants included adult patients (> 16 years), diagnosed with Crohn's disease using conventional clinical, radiographic or endoscopic criteria. DATA COLLECTION AND ANALYSIS: Two authors independently reviewed the titles and abstracts of the studies identified from the literature search. The full text of potentially relevant citations were reviewed for inclusion and the study investigators were contacted as needed for clarification. Any disagreements regarding study eligibility were resolved by discussion and consensus with a third author.Two authors independently extracted and recorded data using a standard form. The following data were recorded from each eligible study: number of patients enrolled; number of patients per treatment arm; patient characteristics: age and gender distribution; description of histologic disease activity index utilized; and outcomes such as content validity, construct validity, criterion validity, responsiveness, intra-rater reliability, inter-rater reliability, and feasibility. MAIN RESULTS: Sixteen reports of 14 studies describing 14 different numerical histological indices fulfilled the inclusion criteria.Inter-rater reliability was assessed in one study. For the Naini and Cortina Score, estimates of correlation were 'almost perfect', ranging from r = 0.94 to 0.96. The methodological quality of this study with respect to reliability was 'good'.With respect to validity, correlation estimates between various histological scoring systems and Crohn's disease activity as measured by objective markers of inflammation (including C-reactive protein, erythrocyte sedimentation rate, fecal calprotectin and fecal lactoferrin); endoscopic disease activity scores; clinical disease activity scores; and quality of life questionnaires were reported. Comparisons between histologic scoring indices and endoscopic scoring indices ranged from no correlation to 'substantial' (r = 0.779). The methodological quality of the studies that explored validity ranged form 'poor' to 'good'.Responsiveness data were available in seven studies. After subjects were administered a treatment of known efficacy, statistically significant change in the index score was demonstrated in five studies with respect to six indices. Two studies failed to indicate whether there was statistically significant change in the index score post-treatment. With regard to methodological quality, six of the studies were rated as 'poor' and one of the studies was rated as 'fair'.Feasibility was assessed by one study. The Naini and Cortina Score was shown to be simple to use and feasible for every given case. AUTHORS' CONCLUSIONS: Currently there is no fully validated histological scoring index for evaluation of Crohn's disease activity. Development of a validated histological scoring index for Crohn's disease is a clinical and research priority.

Does Better Specimen Orientation and a Simplified Grading System Promote More Reliable Histologic Interpretation of Serrated Colon Polyps in the Community Practice Setting? Results of a Nationwide Study.

INTRODUCTION: Colonoscopic surveillance guidelines for serrated polyps (SPs) are predicated upon the histologic characteristics of the index polyp. However, discrimination between SP subtypes [hyperplastic polyps vs. sessile serrated adenoma/polyps (SSA/P)] is often unreliable. MATERIALS AND METHODS: We studied the impact of (1) a novel tissue orientation method, performed in the endoscopy laboratory, whereby polyps are flattened in a small paper envelope immediately after resection (modified protocol); and (2) 2012 consensus-modified criteria (CM-2012). These interventions were compared with conventional tissue-handling protocol (CP) and traditional 2008 World Health Organization criteria (WHO). Twenty blinded community pathologists from around the United States scored 100, independent, 0.5 to 2.0 cm, proximal colonic SPs randomly selected from a 2-site tissue section archive. We compared interobserver agreement and diagnostic grading. RESULTS: Interobserver agreement was higher using CM-2012 than WHO criteria (absolute agreement: 13% vs. 4%, P<0.01; 75% agreement: 54% vs. 38%, P<0.01). Interobserver agreement was higher with the modified protocol than with CP (WHO absolute agreement: 6% vs. 2%, P>0.05; WHO 75% agreement: 46% vs. 30%, P>0.05, and CM-2012 absolute agreement: 20% vs. 6%, P=0.07; CM-2012 75% agreement: 66% vs. 42%, P=0.03). Compared with WHO, use of CM-2012 criteria resulted in fewer diagnoses of "indeterminate"; more diagnoses of SSA/P (P<0.01); and "upgraded" the diagnosis from hyperplastic polyps to SSA/P in approximately 7% of cases. These observations were independent of polyp size, patient gender, and study site. CONCLUSIONS: Simple enhancements to postresection SP handling and diagnostic criteria markedly improve interobserver agreement of SP diagnosis among nongastrointestinal community pathologists. This finding, if confirmed, has important implications for SP colonoscopy surveillance guidelines.

Histology-Guided High-Resolution Matrix-Assisted Laser Desorption Ionization Mass Spectrometry Imaging.

Mass spectrometry imaging (MSI) is widely used for clinical research because when combined with histopathological analysis the molecular signatures of specific cells/regions can be extracted from the often-complex histologies of pathological tissues. The ability of MSI to stratify patients according to disease, prognosis, and response is directly attributable to this cellular specificity. MSI developments are increasingly focused on further improving specificity, through higher spatial resolution to better localize the signals or higher mass resolution to better resolve molecular ions. Higher spatial/mass resolution leads to increased data size and longer data acquisition times. For clinical applications, which analyze large series of patient tissues, this poses a challenge to keep data load and acquisition time manageable. Here we report a new tool to perform histology guided MSI; instead of analyzing large parts of each tissue section the histology from adjacent tissue sections is used to focus the analysis on the areas of interest, e.g., comparable cell types in different patient tissues, thereby minimizing data acquisition time and data load. The histology tissue section is annotated and then automatically registered to the MSI-prepared tissue section; the registration transformation is then applied to the annotations, enabling them to be used to define the MSI measurement regions. Using a series of formalin-fixed, paraffin-embedded human myxoid liposarcoma tissues, we demonstrate an 80% reduction of data load and acquisition time, thereby enabling high resolution (mass or spatial) to be more readily applied to clinical research. The software is freely available for download.

Artifactual Stratum Corneum Calcification of the Beagle Dog Tongue.

Examination of H&E-stained tongue samples from a 26-week intravenous infusion study of Beagle dogs, utilizing a compound with no recognized effect on mineral metabolism, exhibited superficial stratum corneum calcification in both treated and control animals. This resulted in the search for possible causes of the finding to help clarify confounding issues. Retrospective examination of 11 studies performed before the signal case indicated that the problem existed in the testing facility but was not recognized. Prior to 2008, this finding was not observed, perhaps indicating the requirement for a change in procedures or suppliers. Based on the hypothesis that the calcium salts were deposited from bone during processing, a series of tests was performed by fixing tongue and femur along with different tissues, processed routinely to slide, and stained with H&E and von Kossa stains. We conclude that the presence of superficial stratum corneum calcification of the tongue in dogs demonstrated in toxicology studies is an artifactual change related to the processing of tissues, specifically the fixation of tongue in the same container as bone and stomach. This change should not be confused with compound-related effects, even when the incidence varies between controls and treated animals.

Correlation between Endoscopic and Histopathological Findings in Gastric Lesions.

Background Stomach is a common site for wide variety of lesions. The visualisation of the site with biopsy leads to the early detection of the pathologic process and appropriate therapy. Objectives The objective of this study is to correlate the histopathological pattern of endoscopic biopsies with distribution of gastric lesions according to age and sex. Method The retrospective study was carried out among 50 cases with endoscopic biopsies and histopathological assessment, received at Department of Pathology, Dhulikhel Hospital- Kathmandu University Hospital. Result Out of 50 cases majority of cases were of male gender with male: female ratio was 1.3:1. Our study showed a poor correlation between endoscopic and histopathological evidence of inflammation in the stomach. Two cases were diagnosed as intestinal metaplasia which were diagnosed as ulcer and erosion endoscopically. Out of 32% of cases diagnosed endoscopically as ulcer, only one case was confirmed histopathologically. Our study showed good correlation in the cases of carcinoma. Out of 17 cases diagnosed endoscopically as gastric carcinoma correlated histopathologically as gastric adenocarcinoma. Majority of carcinoma cases showed ulcerating fungating growth followed by ulcero-proliferative growth. Conclusion Endoscopy is incomplete without biopsy and histopathology is the gold standard for the diagnosis of endoscopically detected lesions. Endoscopic examination and histopathological examination of suspected gastric lesions should go parallel and neither should be a substitute of each other.

Scientific and Regulatory Policy Committee (SRPC) paper: validation of digital pathology systems in the regulated nonclinical environment.

Digital Pathology Systems (DPS) are dynamic, image-based computer systems that enable the acquisition, management, and interpretation of pathology information generated from digitized glass slides. This article provides a roadmap for (1) qualification of a whole slide scanner (WSS) during a validation project, (2) validation of software required to generate the whole slide image (WSI), and (3) an introduction to visual digital image evaluation and image analysis. It describes a validation approach that can be utilized when validating a DPS. It is not the intent of this article to provide guidance on when validation of DPS is required. Rather, the article focuses on technical aspects of validation of the WSS system (WSS, IT infrastructure, and associated software) portion of a DPS and covers the processes of setting up the WSS for scanning a glass slide through saving a WSI on a server. Validation of a computerized system, such as a DPS, for use in a regulated nonclinical environment is governed by Code of Federal Regulations (CFR) Title 21 part 11: Electronic Records; Electronic Signature and predicate rules associated with Good Laboratory Practices documents including 21 CFR part 58. Similar regulation and predicate rules apply in the European Union and Japan.

Enhanced histopathology of the immune system: a review and update.

Enhanced histopathology (EH) of the immune system is a tool that the pathologist can use to assist in the detection of lymphoid organ lesions when evaluating a suspected immunomodulatory test article within a subchronic study or as a component of a more comprehensive, tiered approach to immunotoxicity testing. There are three primary points to consider when performing EH: (1) each lymphoid organ has separate compartments that support specific immune functions; (2) these compartments should be evaluated individually; and (3) semiquantitative descriptive rather than interpretive terminology should be used to characterize any changes. Enhanced histopathology is a screening tool that should be used in conjunction with study data including clinical signs, gross changes, body weight, spleen and thymus weights, other organ or tissue changes, and clinical pathology. Points to consider include appropriate tissue collection, sectioning, and staining; lesion grading; and diligent comparison with concurrent controls. The value of EH of lymphoid organs is to aid in the identification of target cell type, changes in cell production and cell death, changes in cellular trafficking and recirculation, and determination of mechanism of action.

Imaging and pathological discordance amongst the plethora of breast lesions in breast biopsies.

INTRODUCTION: Imaging-guided breast tissue biopsy has become an acceptable alternative to open surgical biopsy for nonpalpable breast lesions. Discussion of abnormal results of the correlation between imaging and pathological findings can be very challenging as it can assist in decision-making with regard to the further treatment options by arriving at a comprehensive diagnosis. MATERIALS AND METHODS: This was a retrospective study. Radiological data from imaging-guided breast biopsies of 500 patients during a 6-year period was collected and classified by a specialist radiologist as per the BI-RADS format. Histopathology reports were studied and discordance analyzed. RESULTS: A total of 500 cases were reviewed. Approximately 33% (168) cases fell into the BI-RADS 3 category, 24.4% (122) into the BI-RADS 4, and 37% (187) into BI-RADS 5 categories. Approximately 50% (n = 250) cases were benign, 2.6% (13) belonged to the high-risk category, and 47.4% (237) were malignant. The number of discordant cases was 12 (2.4%), mostly due to technical factors. Sensitivity of biopsies to detect malignancy was 85%, specificity was 96%, and accuracy of biopsy in diagnosing cancer was 90%. DISCUSSION: The "triple assessment" is the most sensitive method for detecting early breast cancer. An effective communication pathway must be established between a clinician, radiologist, and pathologist for surgical excision in discordance as it carries a high prevalence of carcinoma in these lesions. CONCLUSION: In discordant cases, either due to abnormal results of imaging or of abnormal pathological findings, the final decision is based on two concordant findings, out of the three parameters. This involves a multidisciplinary breast conference and an active participation by the pathologist.