Chest CT Scan Findings in Children with COVID-19: A Systematic Review.

Objectives: To gather, summarize, and appraise the available evidence on: 1) the accuracy of chest CT scan in diagnosing COVID-19 among children, and 2) the characteristic chest CT scan findings associated with COVID-19 pneumonia in children. Methods: We comprehensively searched databases (MEDLINE, COCHRANE), clinical trial registries, bibliographic lists of selected studies, and unpublished data for relevant studies. Guide questions from the Painless Evidence Based Medicine and the National Institutes of Health Quality Assessment Tools were used to assess study quality. Results: A poor quality study showed 86.0% (95% CI 73.8, 93.0) sensitivity and 75.9% (95% CI 67.1, 83.0) specificity of chest CT scan in diagnosing COVID-19 in children. Thirty-nine observational studies describing chest CT scan in children with COVID-19 showed abnormal findings in 717 of 1028 study subjects. Common chest CT scan findings in this population include: 1) ground glass opacities, patchy shadows, and consolidation, 2) lower lobe involvement, and 3) unilateral lung lesions. Conclusion: Studies which investigate the accuracy of chest CT scan in the diagnosis of COVID-19 in children are limited by heterogeneous populations and small sample sizes. While chest CT scan findings such as patchy shadows, ground glass opacities, and consolidation are common in children with COVID-19, these may be similar to the imaging findings of other respiratory viral illnesses.

Spectroscopic evidence of spinel phase clustering in solid solutions Hg(1-x)Cr(x)Se (0.03 ≤ x ≤ 0.1).

The diluted magnetic semiconductors Hg(1-x)Cr(x)Se (0.03≤x≤0.1) were prepared by the solid state recrystallization method. The structure microanalysis of the Hg(1-x)Cr(x)Se compounds, performed by using a scanning electron spectrometer, has shown that the HgCr(2)Se(4) spinel-like inclusions are present in the host matrix Hg(1-x)Cr(x)Se and their amount increases when the chromium content grows. ESR studies of Hg(1-x)Cr(x)Se samples were carried out in the temperature range 4.2-300 K. ESR spectra of the samples with different chromium contents demonstrate the same g-factors at room temperature and similar fine structure development with the temperature decrease. Numerical studies of g-factors, performed by the modified crystal field approach (MCFA), allowed us to reveal that Cr(2+)/Cr(3+) ions in the tetrahedral environment of the solid solution Hg(1-x)Cr(x)Se cannot lead to the ESR signal. The experimental g-factor is well reproduced by a numerical g-factor for Cr(3+) ions located in the octahedral environment, being specific for the HgCr(2)Se(4) spinel phase. The onset of the ESR fine structure is determined by the trigonal distortions of the (CrSe(6))(9-) octahedral cell. From our study it has been found that the spinel clusters are present in the Hg(1-x)Cr(x)Se solid solution even at low chromium content.

Sentinel lymph node biopsy with metastasis: can axillary dissection be avoided in some patients with breast cancer?

PURPOSE: Recent studies have suggested that the sentinel lymph node (SLN) biopsy is an accurate alternative staging procedure for women with breast cancer. The goal of this study was to identify a subset of breast cancer patients in whom metastatic disease was confined only to the SLN. MATERIALS AND METHODS: From two institutions, we recruited 222 women with breast cancer for SLN biopsy. A SLN biopsy was performed in each patient, followed by an axillary dissection in 182 patients. Histologic and immunohistochemical cytokeratin stains were used on all SLNs. RESULTS: The SLN was identified in 220 (97. 8%) of the 225 biopsies. Evidence of metastatic breast cancer in the SLN was found in 60 (27.0%) of the 222 patients. Of these patients, 32 (53.3%) had evidence of tumor in the SLN only. By multivariate analysis, two factors were found to be significantly associated with a higher likelihood of tumor involvement in the non-SLNs: primary tumor size larger than 2.0 cm (P =.0004) and macrometastasis (> 2.0 mm) in the SLN (P =.002). Additional analysis revealed that none (0%; 95% confidence interval, 0% to 18.5%) of the 18 patients with primary tumors < or = 2.0 cm and micrometastasis to the SLN had remaining axillary lymph node involvement. CONCLUSION: The primary tumor size and metastasis size in the SLN are independent factors in predicting the incidence of tumor in the non-SLNs. Therefore, the SLN biopsy alone may be adequate for staging and/or therapy decision making in patients with primary breast tumors < or = 2.0 cm and micrometastasis in the SLN.

The influence of young age on outcome in early stage breast cancer.

PURPOSE: To assess the impact of young age on outcome in women with early stage breast cancer undergoing conservative surgery and radiation. METHODS AND MATERIALS: Between 1981 and 1991, 980 patients with Stage I and II breast cancer underwent excisional biopsy, axillary dissection, and radiation. The median follow-up was 4.6 years, with a range of 1 month to 11 years. The patients were divided into three groups, based on age at the time of diagnosis: (a) age < or = 35 years--64 patients, (b) age 36-50 years--363 patients, and (c) age > 50 years--553 patients. The comparability of the groups was assessed in terms of clinical factors (tumor size and race), histopathologic factors (histologic subtype, final resection margin, estrogen and progesterone receptor status, pathologic nodal status), and treatment related factors (reexcision, median total dose to the primary, region(s) treated with radiation, and the use of adjuvant systemic chemotherapy and/or tamoxifen). Outcome was evaluated for overall, relapse-free, and cause-specific survival and patterns of first failure (breast, regional nodes, and distant metastasis). RESULTS: There were no significant differences among the three groups in terms of race, clinical tumor size, pathology of the primary tumor, pathologic nodal status, final margin of resection, progesterone receptor status, median total dose to the primary tumor, or the regions treated. However, younger women were significantly more likely to have estrogen receptor negative tumors, undergo reexcision, and receive adjuvant systemic chemotherapy without tamoxifen. Younger women were found to have a statistically significantly decreased 8-year actuarial relapse-free survival (53% vs. 67% vs. 74%, p = 0.009), cause-specific survival (73% vs. 84% vs. 90%, p = 0.02), freedom from distant metastasis (76% vs. 75% vs. 83%, p = 0.02), and a significantly increased risk of breast recurrence (24% vs. 14% vs. 12%, p = 0.001), and regional node recurrence (7% vs. 1% vs. 1%, p = 0.0002). The patients were further divided on the basis of their pathologic nodal status. There were no statistically significant differences among the three age groups for axillary node-positive patients for overall survival (75% vs. 80% vs. 74%), relapse-free survival (73% vs. 73% vs. 62%), cause-specific survival (76% vs. 85% vs. 80%), and freedom from distant metastasis (75% vs. 75% vs. 72%), or breast recurrence (0% vs. 9% vs. 6%). The findings were identical when the analysis was restricted to node-positive patients who received chemotherapy. However, for axillary node-negative women, young age was associated with a statistically significant decreased overall survival (71% vs. 83% vs. 92%), relapse-free survival (51% vs. 65% vs. 76%), cause-specific survival (71% vs. 86% vs. 93%), freedom from distant metastasis (77% vs. 76% vs. 88%), and a statistically significant increased risk of breast recurrence (40% vs. 16% vs. 13%), and regional node recurrence (3% vs. 1% vs. 0%). The risk of a breast recurrence in axillary node-negative young women was decreased by the addition of adjuvant systemic chemotherapy but not by the use of reexcision. CONCLUSIONS: The present analysis demonstrates that young women with early stage breast cancer do significantly worse when compared to older women in terms of relapse-free survival, cause-specific survival, distant metastasis and breast and regional node recurrence. However, the adverse effect of young age on outcome appears to be limited to the node-negative patients. These findings suggest that node-negative early stage breast cancer in young women is a more aggressive disease, with an increased risk for all patterns of failure and a decreased survival.

Congenital bronchopulmonary foregut malformations. Intralobar and extralobar pulmonary sequestrations communicating with the foregut.

Two unusual variants of bronchopulmonary foregut malformations are presented. The first case was that of a 12-year-old male with a history of pectus excavatum in whom severe lobar emphysema developed secondary to an intralobar pulmonary sequestration that communicated with the esophagus. This case was unusual in that foregut communications and associated congenital anomalies are generally believed to be restricted to extralobar pulmonary sequestrations. The second case was that of a 27-year-old woman with an extralobar pulmonary sequestration that communicated with the esophagus. The sequestration was unusual in that it arose in the anterior mediastinum and received the bulk of its blood supply from the pulmonary artery. The occurrence of mixed forms of pulmonary sequestrations supports the hypothesis that extralobar and intralobar sequestrations and sequestrations with foregut communication are related thoracic disorders that are best considered bronchopulmonary foregut malformations.

Factors associated with a positive reexcision after excisional biopsy for invasive breast cancer.

BACKGROUND: Breast-conserving therapy followed by adjuvant radiotherapy represents an alternative to mastectomy as a treatment for invasive breast cancer. When excisional biopsy has been performed outside the parent institution, reexcision is often performed, with tumor being identified in 32% to 62% of the subsequent specimens. We analyzed not only the factors associated with a positive reexcision but also those factors associated with final surgical margins that are positive for tumor. METHODS: Between 1978 and 1991, 956 female patients with American Joint Committee on Cancer clinical stage I or II breast cancer were treated with breast-conserving therapy where a total of 420 patients underwent reexcision after an initial excisional biopsy. Several factors were analyzed to determine their association with a positive reexcision, the status of the final surgical margin, and the nature of the disease present within the reexcision specimen. RESULTS: Factors that correlated with a positive reexcision in both univariate and multivariate analysis were clinical tumor size, method of detection, the pathologic status of the axillary lymph nodes, and the histologic appearance. Those factors associated with finding invasive disease at the time of reexcision were clinical tumor size, clinical presentation, and nodal status. The single factor associated with finding residual in situ disease at the time of reexcision was histologic appearance of the primary tumor. A final positive margin was associated with method of tumor detection, age of the patient, and the presence of axillary lymph node metastases. CONCLUSIONS: The most significant factors associated with a positive reexcision are clinical tumor size, method of tumor detection, pathologic nodal status, and histologic appearance. Patients with larger tumors or those that are detected by physical examination, as well as invasive lobular carcinomas, may require a more generous initial resection to achieve negative surgical margins and avoid the likelihood of reexcision.

MR imaging of the breast.

The results of clinical investigation suggest that MR imaging can provide clinically important information that cannot be obtained with conventional imaging methods, and that this modality will, in the future, be an invaluable adjunctive breast imaging tool just as breast ultrasound is today. MR imaging appears to be the most accurate method for the detection of implant failure, and although it is the most costly of the available implant imaging techniques, it may be the study of choice when there is a question of implant integrity that cannot be answered with conventional methods. MR imaging as a method to detect, diagnose, and stage breast cancer remains in the investigational stage. The specificity of MR imaging appears limited because of the overlap in the enhancement kinetics and morphologic appearance of benign and malignant lesions. In selected cases, the identification of certain morphologic features, such as internal septations or the absence of enhancement, may be used to classify a lesion as benign, offering an alternative to percutaneous or excisional biopsy. MR imaging appears to be very sensitive for the visualization of both invasive carcinoma and DCIS. Perhaps most important, MR imaging can detect invasive and noninvasive breast carcinoma that is both mammographically and clinically occult, offering the potential for more accurate breast cancer staging and optimized treatment planning. MR imaging is emerging as perhaps the most promising imaging modality for breast cancer detection to date. Published results, however, are from studies with relatively small numbers of patients. The results of these studies should be validated in a large-scale clinical trial before MR imaging is implemented clinically, outside of research settings. This type of clinical investigation is needed to define the technical requirements for optimal imaging, to define interpretation criteria, to develop accurate MR imaging guided localization and biopsy systems, to define the clinical indications for which MR imaging should be used as an adjunct to conventional imaging methods, and to address the issue of cost-effectiveness. One such trial, an international, multi-institutional study funded by the National Cancer Institute, is presently underway.

Ipsilateral breast tumor recurrence following conservative surgery and radiation therapy.

Ipsilateral breast tumor recurrence occurs in approximately 10% to 15% of patients undergoing conservative surgery and definitive radiation therapy. Mammography alone detects one third of breast recurrences. Most recurrences are invasive, few demonstrate simultaneous distant metastasis, and approximately 40% have axillary lymph node involvement. Mastectomy is the standard salvage procedure. Axillary lymph node dissection may help guide adjuvant treatment as well as reduce the risk of a subsequent regional recurrence. The decision of whether to use adjuvant therapy should be based on tumor size, lymph node status, receptor status, DNA index, S-phase fraction, and disease-free interval. Ipsilateral recurrence may be an independent prognostic factor for distant metastasis.

Role of magnetic resonance imaging and magnetic resonance imaging--guided surgery in the evaluation of patients with early-stage breast cancer for breast conservation treatment.

Magnetic resonance imaging (MRI) may be more sensitive than mammography for detecting breast cancer and may have an adjunctive role in assessing patients with early-stage disease for breast conservation treatment. This study was performed to analyze the impact of breast MRI on the clinical management of 83 patients being considered for breast conservation treatment. Eighty-three consecutive cases of patients undergoing breast MRI during standard workup and evaluation for breast conservation treatment from 1993 to 1996 were retrospectively reviewed. Records were reviewed for patient and tumor characteristics, mammographic findings, MRI findings, timing of MRI study, findings from MRI-guided surgery (when done), and whether the patient underwent breast conservation treatment. MRI definitely altered management in 15 patients (18%), may have affected management in 4 patients (5%), and did not change management in 64 patients (77%). Thirteen patients underwent additional surgery because of MRI findings; the positive predictive value for MRI-guided surgery was 38% (5 of 13). Ultimately, 82% of the patients received breast conservation treatment. No predictive factor was identified to characterize the patients most likely to have management affected by MRI findings. These findings suggest that breast MRI may be useful in the evaluation of patients with early-stage breast cancer for breast conservation treatment. A larger study population and outcome data will be required to confirm these findings and to define those patients most likely to benefit from breast MRI.

A combined architectural and kinetic interpretation model for breast MR images.

RATIONALE AND OBJECTIVES: The purpose of this study was to integrate contrast material kinetic and architectural data from magnetic resonance (MR) images and to assess the improvement in diagnostic accuracy. MATERIALS AND METHODS: MR imaging data from a diagnostic cohort of 100 patients (50 malignant and 50 benign cases) were analyzed. RESULTS: Qualitative classification of the enhancement curve was the most predictive kinetic feature. Receiver operating characteristic (ROC) curves were calculated for the architectural model alone and for the architectural model combined with the qualitative kinetic classification. The results demonstrated a statistically significant increase in ROC area (P = .03) of the combined model compared with that of the architectural model alone. CONCLUSION: The addition of qualitative classification of the time-signal intensity curve to an architectural interpretation model results in significant improvement in model performance as measured by the area under the ROC curve.

How experience and training influence mammography expertise.

RATIONALE AND OBJECTIVES: The authors evaluated the influence of perceptual and cognitive skills in mammography detection and interpretation by testing three groups representing different levels of mammography expertise in terms of experience, training, and talent with a mammography screening-diagnostic task. MATERIALS AND METHODS: One hundred fifty mammograms, composed of unilateral cranial-caudal and mediolateral oblique views, were displayed in pairs on a digital workstation to 19 radiology residents, three experienced mammographers, and nine mammography technologists. One-third of the mammograms showed malignant lesions; two-thirds were malignancy-free. Observers interacted with the display to indicate whether each image contained no malignant lesions or suspicious lesions indicating malignancy. Decision time was measured as the lesions were localized, classified, and rated for decision confidence. RESULTS: Compared with performance of experts, alternative free response operating characteristic performance for residents was significantly lower and equivalent to that of technologists. Analysis of overall performance showed that, as level of expertise decreased, false-positive results exerted a greater effect on overall decision accuracy over the time course of image perception. This defines the decision speed-accuracy relationship that characterizes mammography expertise. CONCLUSION: Differences in resident performance resulted primarily from lack of perceptual-learning experience during mammography training, which limited object recognition skills and made it difficult to determine differences between malignant lesions, benign lesions, and normal image perturbations. A proposed solution is systematic mentor-guided training that links image perception to feedback about the reasons underlying decision making.

MR imaging of the breast.

The results of clinical investigation suggest that MR imaging can provide clinically important information that cannot be obtained with conventional imaging methods, and that this modality will, in the future, be an invaluable adjunctive breast imaging tool, just as breast imaging is today. MR imaging as a method to detect, diagnose, and stage breast cancer remains in the investigational stage, but is emerging as perhaps the most promising imaging modality for breast cancer detection.

MR guided biopsy of the breast.

This article examines technical and clinical issues related to MR guided biopsy of the breast. Designed features of breast biopsy instrumentation are discussed. Procedures for performing breast biopsies as well as clinical indications are also explored.

MR imaging-guided interventions in the breast.

MR imaging of the breast has high sensitivity for the detection of invasive breast cancer. However, not all enhancing lesions are malignant. A needle localization or biopsy system is necessary to differentiate false positive benign enhancing lesions from the true carcinomas. In this article, the techniques, pitfalls, and potential clinical indications for MR imaging-guided needle localization and percutaneous biopsy are discussed.

Optical imaging of human breast cancer.

Since an increasing number of breast cancers have been reported in recent years, there is a need for improving techniques for early detection of the breast cancer. Here we tested a time gated optical imaging technique as a tool for imaging human breast. Pulsed laser light at wavelengths of 780 and 830 nm are transmitted through human breast tissues and time spectra of the diffused light through the tissue are recorded over nanoseconds. Data from different locations are acquired and used to reconstruct a two dimensional image as a set of spectra in pixel form. The imaging consists of absorption and scattering coefficients, and the absorption coefficients at the two wavelengths are related to oxygen concentration and blood volume. The analysis of these coefficients is based upon the early arrival photons, therefore allowing construction of a better image than those from the current diaphanography. We demonstrate images of breast cancer, cysts created after lumpectomy, and consequences of radiation therapy. Results show that time gated optical imaging can image oxygen concentration in the cancerous and fibrotic breasts. Resolution of the imaging for smaller tumor size needs to be improved.

High-resolution MR imaging of the breast.

Investigation into the use of MRI as a breast imaging tool is ongoing. Several studies have shown that MRI is a very accurate imaging method for the identification of implant failure in the symptomatic patient with augmented breasts. In this clinical setting. MRI may be the study of choice. Imaging techniques, and the MRI appearance of normal and abnormal implants, are described. The use of MRI for the detection of breast cancer is not as straightforward. Preliminary results suggest that this technique can be used as an adjunct to mammography for the detection and diagnosis of breast cancer. However, it is premature to draw firm conclusions regarding the role that MRI should play in the management of women with breast disease because of the wide variability of imaging techniques, protocols, and patient populations in the studies reported to date. In this overview, the current state of MR imaging of the breast is discussed. Technical requirements are described, and potential clinical applications- including the differentiation of benign from malignant lesions, breast cancer staging, detection of recurrence after breast conservation therapy, and detection of cancer in patients presenting with positive axillary lymph nodes with an unknown primary-are reviewed. Many of these potential clinical applications will require an accurate MR-guided biopsy system, and the implementation of such a system as well as its inherent limitations are discussed.

Conservative surgery and radiation for early-stage breast cancer.

In selected patients with early-stage breast cancer, conservative surgery and radiation represent an alternative equal to mastectomy in terms of local recurrence, distant metastasis, survival, and long-term complications. Patients with early-stage breast cancer who are candidates for conservative surgery and radiation include those whose primary tumor is less than 4 to 5 cm in size without evidence of gross multicentricity or diffuse microcalcifications. Patients with an extensive intraductal component may be appropriate candidates provided that margins of resection are negative. Young age is not a contraindication to the conservative treatment. A preexisting history of collagen vascular disease or prior mantle irradiation for Hodgkin's or non-Hodgkin's lymphoma represents a contraindication to conservative surgery and radiation because of the potential for severe complications. An additional contraindication is the pregnant woman in whom delivery cannot be accomplished before the initiation of radiation. Mammography is essential in the pretreatment evaluation and posttreatment follow-up of the conservatively treated patient. The goal of the pretreatment mammogram is to assess the extent of disease in the ipsilateral breast as well as to evaluate the contralateral breast. In patients who present with microcalcifications, a postbiopsy mammogram before radiation is essential to document complete removal of all malignant-appearing microcalcifications. Mammography is an essential part of the follow-up program in order to detect a recurrence in the treated breast as well as a cancer in the contralateral breast cancer. The optimal interval for follow-up mammography has not been determined, although programs employing mammography on a yearly basis after treatment have been associated with the detection of early recurrences and excellent survival after salvage mastectomy for these recurrences.

Chest CT Scan findings in children with COVID-19: A systematic review

Objectives@#To gather, summarize, and appraise the available evidence on: 1) the accuracy of chest CT scan in diagnosing COVID-19 among children, and 2) the characteristic chest CT scan findings associated with COVID-19 pneumonia in children.@*Methods@#We comprehensively searched databases (MEDLINE, COCHRANE), clinical trial registries, bibliographic lists of selected studies, and unpublished data for relevant studies. Guide questions from the Painless Evidence Based Medicine and the National Institutes of Health Quality Assessment Tools were used to assess study quality.@*Results@#A poor quality study showed 86.0% (95% CI 73.8, 93.0) sensitivity and 75.9% (95% CI 67.1, 83.0) specificity of chest CT scan in diagnosing COVID-19 in children. Thirty-nine observational studies describing chest CT scan in children with COVID-19 showed abnormal findings in 717 of 1028 study subjects. Common chest CT scan findings in this population include: 1) ground glass opacities, patchy shadows, and consolidation, 2) lower lobe involvement, and 3) unilateral lung lesions. @*Conclusion@#Studies which investigate the accuracy of chest CT scan in the diagnosis of COVID-19 in children are limited by heterogeneous populations and small sample sizes. While chest CT scan findings such as patchy shadows, ground glass opacities, and consolidation are common in children with COVID-19, these may be similar to the imaging findings of other respiratory viral illnesses.

Multi-minimum adiabatic potential in the single crystal normal spinel ZnAl(2)O(4), doped by Cu(2+) ions.

Spectroscopic investigations of a ZnAl(2)O(4) spinel doped with bivalent copper ions of 0.05% concentration have been carried out in the temperature range 4.2-290 K using a 3 cm(-1) range electron paramagnetic resonance (EPR) spectrometer having an operational frequency f = (9.241 ± 0.001) GHz. The spectrum can be represented as a superposition of two components: a low-temperature (LT) and a high-temperature (HT) one. Redistribution of integrated intensity between HT and LT components of the spectra occurs with temperature change that is typical of systems with multi-minimum adiabatic potential. Spectra observed are explained within the modified theory of crystalline field (MTCF). The electron levels of a Cu(2+) ion placed in an octahedral coordination center with trigonal distortion [CuO(6)](10-) have been calculated. The influence of possible types of oxygen octahedron distortions and possible displacement of copper ions from the symmetry center on the electron spectrum, as well as the shape of the adiabatic potential, has been analyzed. It is shown that in the low-temperature phase the multiple minima of the adiabatic potential occur due to tetragonal distortions while the depth of a minimum is determined by the degree of trigonal octahedron distortions. Tetragonal distortion values and multi-minimum potential barrier heights have been determined.