The role of Micro-CT in imaging breast cancer specimens.

PURPOSE: The goal of breast cancer surgery is to remove all of the cancer with a minimum of normal tissue, but absence of full 3-dimensional information on the specimen makes this difficult to achieve. METHOD: Micro-CT is a high resolution, X-ray, 3D imaging method, widely used in industry but rarely in medicine. RESULTS: We imaged and analyzed 173 partial mastectomies (129 ductal carcinomas, 14 lobular carcinomas, 28 DCIS). Imaging was simple and rapid. The size and shape of the cancers seen on Micro-CT closely matched the size and shape of the cancers seen at specimen dissection. Micro-CT images of multicentric/multifocal cancers revealed multiple non-contiguous masses. Micro-CT revealed cancer touching the specimen edge for 93% of the 114 cases judged margin positive by the pathologist, and 28 of the cases not seen as margin positive on pathological analysis; cancer occupied 1.55% of surface area when both the pathologist and Micro-CT suggested cancer at the edge, but only 0.45% of surface area for the "Micro-CT-Only-Positive Cases". Thus, Micro-CT detects cancers that touch a very small region of the specimen surface, which is likely to be missed on sectioning. CONCLUSIONS: Micro-CT provides full 3D images of breast cancer specimens, allowing one to identify, in minutes rather than hours, while the patient is in OR, margin-positive cancers together with information on where the cancer touches the edge, in a fashion more accurate than possible from the histology slides alone.

American Cancer Society lung cancer screening guidelines.

Findings from the National Cancer Institute's National Lung Screening Trial established that lung cancer mortality in specific high-risk groups can be reduced by annual screening with low-dose computed tomography. These findings indicate that the adoption of lung cancer screening could save many lives. Based on the results of the National Lung Screening Trial, the American Cancer Society is issuing an initial guideline for lung cancer screening. This guideline recommends that clinicians with access to high-volume, high-quality lung cancer screening and treatment centers should initiate a discussion about screening with apparently healthy patients aged 55 years to 74 years who have at least a 30-pack-year smoking history and who currently smoke or have quit within the past 15 years. A process of informed and shared decision-making with a clinician related to the potential benefits, limitations, and harms associated with screening for lung cancer with low-dose computed tomography should occur before any decision is made to initiate lung cancer screening. Smoking cessation counseling remains a high priority for clinical attention in discussions with current smokers, who should be informed of their continuing risk of lung cancer. Screening should not be viewed as an alternative to smoking cessation.

Variability in Predictions from Online Tools: A Demonstration Using Internet-Based Melanoma Predictors.

BACKGROUND: Prognostic models are increasingly being made available online, where they can be publicly accessed by both patients and clinicians. These online tools are an important resource for patients to better understand their prognosis and for clinicians to make informed decisions about treatment and follow-up. The goal of this analysis was to highlight the possible variability in multiple online prognostic tools in a single disease. METHODS: To demonstrate the variability in survival predictions across online prognostic tools, we applied a single validation dataset to three online melanoma prognostic tools. Data on melanoma patients treated at Memorial Sloan Kettering Cancer Center between 2000 and 2014 were retrospectively collected. Calibration was assessed using calibration plots and discrimination was assessed using the C-index. RESULTS: In this demonstration project, we found important differences across the three models that led to variability in individual patients' predicted survival across the tools, especially in the lower range of predictions. In a validation test using a single-institution data set, calibration and discrimination varied across the three models. CONCLUSIONS: This study underscores the potential variability both within and across online tools, and highlights the importance of using methodological rigor when developing a prognostic model that will be made publicly available online. The results also reinforce that careful development and thoughtful interpretation, including understanding a given tool's limitations, are required in order for online prognostic tools that provide survival predictions to be a useful resource for both patients and clinicians.

A Study of the Growth Patterns of Breast Carcinoma Using 3D Reconstruction: A Pilot Study.

Lumpectomy with microscopically clear margins is a safe and effective approach for surgical management of breast carcinoma. Margins are positive for tumor in 18-50% of lumpectomies, as it is not possible to accurately determine the shape or microscopic borders of a tumor preoperatively or intraoperatively. We examined the 3D microanatomy and growth patterns of common breast carcinoma subtypes to provide guidance for lumpectomy surgery. Prospective consent was obtained for the use of excess tissue from patients undergoing lumpectomy or mastectomy for breast carcinoma. Tissue blocks from nine breast carcinomas were serially sectioned. Hematoxylin and eosin-stained slides at 100 µm intervals were scanned using a Nanozoomer (Hamamatsu, Japan) microscopic-resolution scanner. Three-dimensional reconstructions of tumors were created from scanned images using Reconstruct, open-access software. Breast carcinoma subtypes demonstrated characteristic growth patterns within breast tissue, which may have implications for lumpectomy surgery. Invasive ductal carcinomas showed a spherical shape, with a spiculated surface representing tumor cells infiltrating into surrounding parenchyma. Ductal carcinoma in situ appeared to spread along the duct system, creating dilated, tortuous, tumor-filled ducts. The invasive lobular carcinomas examined had a haphazard, linear, infiltrative growth pattern, different from the shape seen in ductal carcinomas. Our preliminary work suggests that invasive ductal and invasive lobular carcinomas appear to have distinct growth patterns in three dimensions and ductal carcinoma in situ appears to grow in a linear fashion along the duct network. The microanatomy studies described have the potential to guide refinements in breast lumpectomy technique.

The Role of Micro-CT in 3D Histology Imaging.

OBJECTIVES: 3D histology tissue modeling is a useful analytical technique for understanding anatomy and disease at the cellular level. However, the current accuracy of 3D histology technology is largely unknown, and errors, misalignment and missing information are common in 3D tissue reconstruction. We used micro-CT imaging technology to better understand these issues and the relationship between fresh tissue and its 3D histology counterpart. METHODS: We imaged formalin-fixed and 2% Lugol-stained mouse brain, human uterus and human lung tissue with micro-CT. We then conducted image analyses on the tissues before and after paraffin embedding using 3D Slicer and ImageJ software to understand how tissue changes between the fixation and embedding steps. RESULTS: We found that all tissue samples decreased in volume by 19.2-61.5% after embedding, that micro-CT imaging can be used to assess the integrity of tissue blocks, and that micro-CT analysis can help to design an optimized tissue-sectioning protocol. CONCLUSIONS: Micro-CT reference data help to identify where and to what extent tissue was lost or damaged during slide production, provides valuable anatomical information for reconstructing missing parts of a 3D tissue model, and aids in correcting reconstruction errors when fitting the image information in vivo and ex vivo.

Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update From the American Cancer Society.

IMPORTANCE: Breast cancer is a leading cause of premature mortality among US women. Early detection has been shown to be associated with reduced breast cancer morbidity and mortality. OBJECTIVE: To update the American Cancer Society (ACS) 2003 breast cancer screening guideline for women at average risk for breast cancer. PROCESS: The ACS commissioned a systematic evidence review of the breast cancer screening literature to inform the update and a supplemental analysis of mammography registry data to address questions related to the screening interval. Formulation of recommendations was based on the quality of the evidence and judgment (incorporating values and preferences) about the balance of benefits and harms. EVIDENCE SYNTHESIS: Screening mammography in women aged 40 to 69 years is associated with a reduction in breast cancer deaths across a range of study designs, and inferential evidence supports breast cancer screening for women 70 years and older who are in good health. Estimates of the cumulative lifetime risk of false-positive examination results are greater if screening begins at younger ages because of the greater number of mammograms, as well as the higher recall rate in younger women. The quality of the evidence for overdiagnosis is not sufficient to estimate a lifetime risk with confidence. Analysis examining the screening interval demonstrates more favorable tumor characteristics when premenopausal women are screened annually vs biennially. Evidence does not support routine clinical breast examination as a screening method for women at average risk. RECOMMENDATIONS: The ACS recommends that women with an average risk of breast cancer should undergo regular screening mammography starting at age 45 years (strong recommendation). Women aged 45 to 54 years should be screened annually (qualified recommendation). Women 55 years and older should transition to biennial screening or have the opportunity to continue screening annually (qualified recommendation). Women should have the opportunity to begin annual screening between the ages of 40 and 44 years (qualified recommendation). Women should continue screening mammography as long as their overall health is good and they have a life expectancy of 10 years or longer (qualified recommendation). The ACS does not recommend clinical breast examination for breast cancer screening among average-risk women at any age (qualified recommendation). CONCLUSIONS AND RELEVANCE: These updated ACS guidelines provide evidence-based recommendations for breast cancer screening for women at average risk of breast cancer. These recommendations should be considered by physicians and women in discussions about breast cancer screening.

A failure analysis of invasive breast cancer: most deaths from disease occur in women not regularly screened.

BACKGROUND: Mortality reduction from mammographic screening is controversial. Individual randomized trials and meta-analyses demonstrate statistically significant mortality reductions in all age groups invited to screening. In women actually screened, mortality reductions are greater. Individual trials and meta-analyses show varying rates of mortality reduction, leading to questions about screening's value and whether treatment advances have diminished the importance of early detection. This study hypothesized that breast cancer deaths predominantly occurred in unscreened women. METHODS: Invasive breast cancers diagnosed between 1990 and 1999 were followed through 2007. Data included demographics, mammography use, surgical and pathology reports, and recurrence and death dates. Mammograms were categorized as screening or diagnostic based on absence or presence of breast signs or symptoms, and were substantiated by medical records. Breast cancer deaths were defined after documentation of prior distant metastases. Absence of recurrent cancer and lethal other diseases defined death from other causes. RESULTS: Invasive breast cancer failure analysis defined 7301 patients between 1990 and 1999, with 1705 documented deaths from breast cancer (n = 609) or other causes (n = 905). Among 609 confirmed breast cancer deaths, 29% were among women who had been screened (19% screen-detected and 10% interval cancers), whereas 71% were among unscreened women, including > 2 years since last mammogram (6%), or never screened (65%). Overall, 29% of cancer deaths were screened, whereas 71% were unscreened. Median age at diagnosis of fatal cancers was 49 years; in deaths not from breast cancer, median age at diagnosis was 72 years. CONCLUSIONS: Most deaths from breast cancer occur in unscreened women. To maximize mortality reduction and life-years gained, initiation of regular screening before age 50 years should be encouraged.

Designing audience-centered interactive voice response messages to promote cancer screenings among low-income Latinas.

INTRODUCTION: Cancer screening rates among Latinas are suboptimal. The objective of this study was to explore how Latinas perceive cancer screening and the use and design of interactive voice response (IVR) messages to prompt scheduling of 1 or more needed screenings. METHODS: Seven focus groups were conducted with Latina community health center patients (n = 40) in need of 1 or more cancer screenings: 5 groups were of women in need of 1 cancer screening (breast, cervical, or colorectal), and 2 groups were of women in need of multiple screenings. A bilingual researcher conducted all focus groups in Spanish using a semistructured guide. Focus groups were recorded, transcribed, and translated into English for analysis. Emergent themes were identified by using thematic content analysis. RESULTS: Participants were familiar with cancer screening and viewed it positively, although barriers to screening were identified (unaware overdue for screening, lack of physician referral, lack of insurance or insufficient insurance coverage, embarrassment or fear of screening procedures, fear of screening outcomes). Women needing multiple screenings voiced more concern about screening procedures, whereas women in need of a single screening expressed greater worry about the screening outcome. Participants were receptive to receiving IVR messages and believed that culturally appropriate messages that specified needed screenings while emphasizing the benefit of preventive screening would motivate them to schedule needed screenings. CONCLUSION: Participants' receptiveness to IVR messages suggests that these messages may be an acceptable strategy to promote cancer screening among underserved Latina patients. Additional research is needed to determine the effectiveness of IVR messages in promoting completion of cancer screening.

Micro-computed tomography (Micro-CT): a novel approach for intraoperative breast cancer specimen imaging.

Intraoperative radiographic examination of breast specimens is commonly performed to confirm excision of image-detected breast lesions, but it is not reliable for assessing margin status. A more accurate method of intraoperative breast specimen imaging is needed. Micro-CT provides quantitative imaging parameters, image rotation, and virtual "slicing" of intact breast specimens. We explored the use of micro-CT for assessment of a variety of clinical breast specimens. Specimens were evaluated with a table top micro-CT scanner, Skyscan 1173 (Skyscan, Belgium), with a 40-130 kV, 8 W X-ray source. Skyscan software for 3D image analysis (Dataviewer and CTVox) was employed to review 3D graphics of specimens. Scanning for 7 min and another 7 min for image reconstruction provided the desired resolution for breast specimens. Breast lumpectomy specimens, shaved cavity margins, mastectomy specimens, and axillary lymph nodes were imaged by micro-CT. The micro-CT images could be rotated in all directions and cross sections of internal portions of specimens could be visualized from any angle. This provided information about spatial orientation of masses and calcifications relative to margins in intact lumpectomy specimens. Micro-CT is a potentially useful tool for assessment of breast cancer specimens, allowing real-time analysis of tumor location in breast lumpectomy specimens or shaved cavity margins. Micro-CT may also be useful for assessing sentinel lymph nodes and mastectomy specimens.

A pilot study evaluating shaved cavity margins with micro-computed tomography: a novel method for predicting lumpectomy margin status intraoperatively.

Microscopically clear lumpectomy margins are essential in breast conservation, as involved margins increase local recurrence. Currently, 18-50% of lumpectomies have close or positive margins that require re-excision. We assessed the ability of micro-computed tomography (micro-CT) to evaluate lumpectomy shaved cavity margins (SCM) intraoperatively to determine if this technology could rapidly identify margin involvement by tumor and reduce re-excision rates. Twenty-five SCM from six lumpectomies were evaluated with a Skyscan 1173 table top micro-CT scanner (Skyscan, Belgium). Micro-CT results were compared to histopathological results. We scanned three SCM at once with a 7-minute scanning protocol, and studied a total of 25 SCM from six lumpectomies. Images of the SCM were evaluated for radiographic signs of breast cancer including clustered microcalcifications and spiculated masses. SCM were negative by micro-CT in 19/25 (76%) and negative (≥2 mm) by histopathology in 19/25 (76%). Margin status by micro-CT was concordant with histopathology in 23/25 (92%). Micro-CT overestimated margin involvement in 1/25 and underestimated margin involvement in 1/25. Micro-CT had an 83.3% positive predictive value, a 94.7% negative predictive value, 83.3% sensitivity, and 94.7% specificity for evaluation of SCM. Evaluation of SCM by micro-CT is an accurate and promising method of intraoperative margin assessment in breast cancer patients. The scanning time required is short enough to permit real-time feedback to the operating surgeon, allowing immediate directed re-excision.

Volumetric Tissue Imaging of Surgical Tissue Specimens Using Micro-Computed Tomography: An Emerging Digital Pathology Modality for Nondestructive, Slide-Free Microscopy-Clinical Applications of Digital Pathology in 3 Dimensions.

OBJECTIVES: Micro-computed tomography (micro-CT) is a novel, nondestructive, slide-free digital imaging modality that enables the acquisition of high-resolution, volumetric images of intact surgical tissue specimens. The aim of this systematic mapping review is to provide a comprehensive overview of the available literature on clinical applications of micro-CT tissue imaging and to assess its relevance and readiness for pathology practice. METHODS: A computerized literature search was performed in the PubMed, Scopus, Web of Science, and CENTRAL databases. To gain insight into regulatory and financial considerations for performing and examining micro-CT imaging procedures in a clinical setting, additional searches were performed in medical device databases. RESULTS: Our search identified 141 scientific articles published between 2000 and 2021 that described clinical applications of micro-CT tissue imaging. The number of relevant publications is progressively increasing, with the specialties of pulmonology, cardiology, otolaryngology, and oncology being most commonly concerned. The included studies were mostly performed in pathology departments. Current micro-CT devices have already been cleared for clinical use, and a Current Procedural Terminology (CPT) code exists for reimbursement of micro-CT imaging procedures. CONCLUSIONS: Micro-CT tissue imaging enables accurate volumetric measurements and evaluations of entire surgical specimens at microscopic resolution across a wide range of clinical applications.

A two-gene expression ratio predicts clinical outcome in breast cancer patients treated with tamoxifen.

Tamoxifen significantly reduces tumor recurrence in certain patients with early-stage estrogen receptor-positive breast cancer, but markers predictive of treatment failure have not been identified. Here, we generated gene expression profiles of hormone receptor-positive primary breast cancers in a set of 60 patients treated with adjuvant tamoxifen monotherapy. An expression signature predictive of disease-free survival was reduced to a two-gene ratio, HOXB13 versus IL17BR, which outperformed existing biomarkers. Ectopic expression of HOXB13 in MCF10A breast epithelial cells enhances motility and invasion in vitro, and its expression is increased in both preinvasive and invasive primary breast cancer. The HOXB13:IL17BR expression ratio may be useful for identifying patients appropriate for alternative therapeutic regimens in early-stage breast cancer.

Dynamics of the Zebrafish Skeleton in Three Dimensions During Juvenile and Adult Development.

Zebrafish are a valuable model for normal vertebrate skeletogenesis and the study of myriad bone disorders. Bones grow, ossify and change shape throughout the zebrafish lifetime, and 3D technologies allow us to examine skeletogenic processes in detail through late developmental stages. To facilitate analysis of shape, orientation and tissue density of skeletal elements throughout ontogeny and adulthood, we generated a high-resolution skeletal reference dataset of wild-type zebrafish development. Using microCT technology, we produced 3D models of the skeletons of individuals ranging from 12 to 25 mm standard length (SL). We analyzed the dynamics of skeletal density and volume as they increase during juvenile and adult growth. Our resource allows anatomical comparisons between meristic units within an individual-e.g., we show that the vertebral canal width increases posteriorly along the spine. Further, structures may be compared between individuals at different body sizes: we highlight the shape changes that the lower jaw undergoes as fish mature from juvenile to adult. We show that even reproductively mature adult zebrafish (17-25 mm SL) continue to undergo substantial changes in skeletal morphology and composition with continued adult growth. We provide a segmented model of the adult skull and a series of interactive 3D PDFs at a range of key stages. These resources allow changes in the skeleton to be assessed quantitatively and qualitatively through late stages of development, and can serve as anatomical references for both research and education.

The non-breast-cancer death rate among breast cancer patients.

Non-breast-cancer deaths currently account for almost half of deaths among breast carcinoma patients in the 15 years following diagnosis. Understanding the trends of non-breast-cancer death is vital for calibrating treatment and survival expectations, and for understanding the consequences of potentially toxic therapies. To observe trends over time in non-breast-cancer relative survival-the non-breast-cancer survival rates of breast cancer patients relative to the non-breast-cancer survival rates of the population as a whole, matched for gender, race, age, region, and year of diagnosis. Non-breast-cancer relative survival between breast carcinoma patients and the general population was measured using SEER public-use data of patients diagnosed with breast carcinoma between 1973 and 2007. Non-breast-cancer relative survival improved significantly from 1973 to the present. From 1986 onward, the non-breast-cancer survival rate among breast carcinoma patients is equal to, or slightly higher than, matched populations who did not have breast carcinoma. This improvement over time occurred across almost all patient stratifications, including race, age, tumor size, and nodal status. However, patients receiving full mastectomies, and patients not receiving radiotherapy experienced no increase in relative survival. The most dramatic relative survival improvements occurred in patients who received radiation and patients receiving partial mastectomies, and such improvements were seen even after controlling for changes in tumor size over time. Non-breast-cancer relative survival among breast carcinoma patients has improved significantly since 1973; breast cancer patients are currently no more likely to die of other causes than the general population.

Improved web-based calculators for predicting breast carcinoma outcomes.

We describe a set of web-based calculators, available at http://www.CancerMath.net , which estimate the risk of breast carcinoma death, the reduction in life expectancy, and the impact of various adjuvant treatment choices. The published SNAP method of the binary biological model of cancer metastasis uses information on tumor size, nodal status, and other prognostic factors to accurately estimate of breast cancer lethality at 15 years after diagnosis. By combining these 15-year lethality estimates with data on the breast cancer hazard function, breast cancer lethality can be estimated at each of the 15 years after diagnosis. A web-based calculator was then created to visualize the estimated lethality with and without a range of adjuvant therapy options at any of the 15 years after diagnosis, and enable conditional survival calculations. NIH population data was used to estimate non-breast-cancer chance of death. The accuracy of the calculators was tested against two large breast carcinoma datasets: 7,907 patients seen at two academic hospitals and 362,491 patients from the SEER national dataset. The calculators were found to be highly accurate and specific, as seen by their capacity for stratifying patients into groups differing by as little as a 2% risk of death, and accurately accounting for nodal status, histology, grade, age, and hormone receptor status. Our breast carcinoma calculators provide accurate and useful estimates of the risk of death, which can aid in analysis of the various adjuvant therapy options available to each patient.

Prevalence and implications of multiple cancer screening needs among Hispanic community health center patients.

OBJECTIVES: To examine adherence rates for multiple cancer screening tests, which will inform prevention efforts in community health centers (CHCs). METHODS: We report on the prevalence of screening for multiple cancers (cervical, breast and colorectal) among 43,000 patients who are predominantly Hispanic, in four CHC sites that share an integrated electronic medical record. RESULTS: Among the 20,057 patients eligible for at least one test, 43% of the population was current on all screening targets; 15,887 additional screening tests were needed among 11,526 individuals. CONCLUSIONS: Expanding use of health information technology in community health centers provides an opportunity to create an electronic infrastructure for addressing multiple screening needs from a patient-centered perspective.

Clinical value of radiographic staging in patients diagnosed with AJCC stage III melanoma.

BACKGROUND: Patients with American Joint Committee on Cancer (AJCC) stage III melanoma represent patients with high risk of systemic relapse. This study evaluates the clinical utility of standardized radiographic staging. METHODS: Consecutive asymptomatic patients underwent standardized radiographic staging workup within 6 weeks of diagnosis. True- and false-positive rates and number of additional examinations generated after a positive initial report were quantified. All suspicious findings were further studied by biopsy and/or by clinical or radiologic assessment. RESULTS: Fifty-eight patients underwent complete radiographic staging. Nineteen (33%) had ulcerated primary tumors. Forty-two patients (73%) presented with clinically negative lymph nodes that were positive on sentinel lymph node biopsy. Lymph node involvement was classified as N1a in 54%, N2a in 19%, N2b in 3%, and N3 in 22% of patients. Among 204 staging examinations in 58 patients, 52 (25%) were initially reported as positive. Three percent of all examinations proved truly positive; 23% were falsely positive. Analyzed per patient, in 37 (64%) of 58 patients, at least one examination was initially reported as positive. However, only 3 patients (5%) had a true-positive and 34 (59%) had at least one false-positive report. The positive reports of the staging scans generated 45 additional examinations (0.78 per patient). CONCLUSIONS: Radiographic staging in asymptomatic patients with stage III melanoma detects a low number of patients with unsuspected systemic disease. The ratio of falsely to truly positive is approximately 11:1. Radiographic screening should only be considered in patients with high-risk prognostic features or symptoms, or in the context of clinical trials.

Volumetric Imaging of Lung Tissue at Micrometer Resolution: Clinical Applications of Micro-CT for the Diagnosis of Pulmonary Diseases.

Micro-computed tomography (micro-CT) is a promising novel medical imaging modality that allows for non-destructive volumetric imaging of surgical tissue specimens at high spatial resolution. The aim of this study is to provide a comprehensive assessment of the clinical applications of micro-CT for the tissue-based diagnosis of lung diseases. This scoping review was conducted in accordance with the PRISMA Extension for Scoping Reviews, aiming to include every clinical study reporting on micro-CT imaging of human lung tissues. A literature search yielded 570 candidate articles, out of which 37 were finally included in the review. Of the selected studies, 9 studies explored via micro-CT imaging the morphology and anatomy of normal human lung tissue; 21 studies investigated microanatomic pulmonary alterations due to obstructive or restrictive lung diseases, such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, and cystic fibrosis; and 7 studies examined the utility of micro-CT imaging in assessing lung cancer lesions (n = 4) or in transplantation-related pulmonary alterations (n = 3). The selected studies reported that micro-CT could successfully detect several lung diseases providing three-dimensional images of greater detail and resolution than routine optical slide microscopy, and could additionally provide valuable volumetric insight in both restrictive and obstructive lung diseases. In conclusion, micro-CT-based volumetric measurements and qualitative evaluations of pulmonary tissue structures can be utilized for the clinical management of a variety of lung diseases. With micro-CT devices becoming more accessible, the technology has the potential to establish itself as a core diagnostic imaging modality in pathology and to enable integrated histopathologic and radiologic assessment of lung cancer and other lung diseases.

Current clinical applications and potential perspective of micro-computed tomography in cardiovascular imaging: A systematic scoping review.

Micro-computed tomography (micro-CT) constitutes an emerging imaging technique, which can be utilized in cardiovascular medicine to study in-detail the microstructure of heart and vessels. This paper aims to systematically review the clinical utility of micro-CT in cardiovascular imaging and propose future applications of micro-CT imaging in cardiovascular research. A systematic scoping review was conducted by searching for original studies written in English according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for scoping reviews. Medline, Scopus, ClinicalTrials.gov, and the Cochrane library were systematically searched through December 11, 2020 to identify publications concerning micro-CT applications in cardiovascular imaging. Preclinical-animal studies and case reports were excluded. The Newcastle-Ottawa assessment scale for observational studies was used to evaluate study quality. In total, the search strategy identified 30 studies that report on micro-CT-based cardiovascular imaging and satisfy our eligibility criteria. Across all included studies, the total number of micro-CT scanned specimens was 1,227. Six studies involved postmortem 3D-reconstruction of congenital heart defects, while eleven studies described atherosclerotic vessel (coronary or carotid) characteristics. Thirteen other studies employed micro-CT for the assessment of medical devices (mainly stents or prosthetic valves). In conclusion, micro-CT is a novel imaging modality, effectively adapted for the 3D visualization and analysis of cardiac soft tissues and devices at high spatial resolution. Its increasing use could make significant contributions to our improved understanding of the histopathophysiology of cardiovascular diseases, and, thus, has the potential to optimize interventional procedures and technologies, and ultimately improve patient outcomes.

Micro-CT-Based Quantification of Extracted Thrombus Burden Characteristics and Association With Angiographic Outcomes in Patients With ST-Elevation Myocardial Infarction: The QUEST-STEMI Study.

Background: Angiographic detection of thrombus in STEMI is associated with adverse outcomes. However, routine thrombus aspiration failed to demonstrate the anticipated benefit. Hence, management of high coronary thrombus burden remains challenging. We sought to assess for the first time extracted thrombotic material characteristics utilizing micro-computed tomography (micro-CT). Methods: One hundred thirteen STEMI patients undergoing thrombus aspiration were enrolled. Micro-CT was undertaken to quantify retrieved thrombus volume, surface, and density. Correlation of these indices with angiographic and electrocardiographic outcomes was performed. Results: Mean aspirated thrombus volume, surface, and density (±standard deviation) were 15.71 ± 20.10 mm3, 302.89 ± 692.54 mm2, and 3139.04 ± 901.88 Hounsfield units, respectively. Aspirated volume and surface were significantly higher (p < 0.001) in patients with higher angiographic thrombus burden. After multivariable analysis, independent predictors for thrombus volume were reference vessel diameter (RVD) (p = 0.011), right coronary artery (RCA) (p = 0.039), and smoking (p = 0.027), whereas RVD (p = 0.018) and RCA (p = 0.019) were predictive for thrombus surface. Thrombus volume and surface were independently associated with distal embolization (p = 0.007 and p = 0.028, respectively), no-reflow phenomenon (p = 0.002 and p = 0.006, respectively), and angiographically evident residual thrombus (p = 0.007 and p = 0.002, respectively). Higher thrombus density was correlated with worse pre-procedural TIMI flow (p < 0.001). Patients with higher aspirated volume and surface developed less ST resolution (p = 0.042 and p = 0.023, respectively). Conclusions: Angiographic outcomes linked with worse prognosis were more frequent among patients with larger extracted thrombus. Despite retrieving larger thrombus load in these patients, current thrombectomy devices fail to deal with thrombotic material adequately. Further studies of novel thrombus aspiration technologies are warranted to improve patient outcomes. Clinical Trial Registration: QUEST-STEMI trial ClinicalTrials.gov number: NCT03429608 Date of registration: February 12, 2018. The study was prospectively registered.