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1.
Cureus ; 15(5): e39031, 2023 May.
Article in English | MEDLINE | ID: mdl-37323365

ABSTRACT

Illicit drugs, especially those injected intravenously, are becoming increasingly more common worldwide. Individuals who use intravenous drugs often reuse or share needles which predisposes them to life-threatening infections. We present the case of a patient who was injecting intravenous drugs into her internal jugular vein, which eventually led to acutely worsening sepsis secondary to fungal infective endocarditis and bilateral septic pulmonary emboli. Transthoracic echocardiogram demonstrated multilobulated and spherical vegetations on the tricuspid and mitral valves, respectively. On computed tomography of the thorax, numerous cavitary lesions and ground-glass opacities were present in both lungs. Multiple hyperdense, linear structures consistent with broken needles were seen on chest radiography. It is important for radiologists to recognize the possibility of broken needles in patients with a history of intravenous drug use as astute recognition of broken needles may lead to better source control and improved outcomes.

2.
Int J Cardiovasc Imaging ; 38(8): 1825-1836, 2022 Aug.
Article in English | MEDLINE | ID: mdl-35194707

ABSTRACT

Recognizing early cardiac sarcoidosis (CS) imaging phenotypes can help identify opportunities for effective treatment before irreversible myocardial pathology occurs. We aimed to characterize regional CS myocardial remodeling features correlating with future adverse cardiac events by coupling automated image processing and data analysis on cardiac magnetic resonance (CMR) imaging datasets. A deep convolutional neural network (DCNN) was used to process a CMR database of a 10-year cohort of 117 consecutive biopsy-proven sarcoidosis patients. The maximum relevance - minimum redundancy method was used to select the best subset of all the features-24 (from manual processing) and 232 (from automated processing) left ventricular (LV) structural/functional features. Three machine learning (ML) algorithms, logistic regression (LogR), support vector machine (SVM) and multi-layer neural networks (MLP), were used to build classifiers to categorize endpoints. Over a median follow-up of 41.8 (inter-quartile range 20.4-60.5) months, 35 sarcoidosis patients experienced a total of 43 cardiac events. After manual processing, LV ejection fraction (LVEF), late gadolinium enhancement, abnormal segmental wall motion, LV mass (LVM), LVMI index (LVMI), septal wall thickness, lateral wall thickness, relative wall thickness, and wall thickness of 9 (out of 17) individual LV segments were significantly different between patients with and without endpoints. After automated processing, LVEF, end-diastolic volume, end-systolic volume, LV mass and wall thickness of 92 (out of 216) individual LV segments were significantly different between patients with and without endpoints. To achieve the best predictive performance, ML algorithms selected lateral wall thickness, abnormal segmental wall motion, septal wall thickness, and increased wall thickness of 3 individual segments after manual image processing, and selected end-diastolic volume and 7 individual segments after automated image processing. LogR, SVM and MLP based on automated image processing consistently showed better predictive accuracies than those based on manual image processing. Automated image processing with a DCNN improves data resolution and regional CS myocardial remodeling pattern recognition, suggesting that a framework coupling automated image processing with data analysis can help clinical risk stratification.


Subject(s)
Cardiovascular Diseases , Deep Learning , Sarcoidosis , Humans , Contrast Media , Magnetic Resonance Imaging, Cine/methods , Predictive Value of Tests , Gadolinium , Ventricular Function, Left , Stroke Volume , Sarcoidosis/diagnostic imaging
3.
Radiol Case Rep ; 16(11): 3250-3254, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34484526

ABSTRACT

Tracheal and bronchial diverticula are outpouchings arising from the trachea or bronchus. We present a case of a 35-year-old female who presented to the emergency department following a motor vehicle accident and was found to have multiple round, air-filled structures within the mediastinum on computed tomography of the thorax, concerning for pneumomediastinum. The patient had a negative fluoroscopic esophagography and subsequent imaging indicated tracheal and bronchial diverticula. While they are often asymptomatic and incidentally found, tracheal and bronchial diverticula may be misdiagnosed as pneumomediastinum, especially in the setting of blunt or penetrating trauma to the thorax.

4.
Radiol Case Rep ; 16(8): 2158-2163, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34158908

ABSTRACT

Mucoepidermoid carcinoma of the thymus is a rare primary thymic carcinoma. Radiologic imaging of this malignancy is rarely reported in literature. We present a patient who complained of a chronic cough for two years who was later found to have mucoepidermoid carcinoma of the thymus. Chest radiograph revealed a large anterior mediastinal mass. Follow-up computed tomography of the thorax demonstrated a large, heterogeneous anterior mediastinal mass with traversing vessels. F-18 fluorodeoxyglucose positron emission tomography-computed tomography demonstrated high avidity in the lesion with areas of diminished activity thought to represent necrosis. Following surgical resection, pathology revealed high-grade mucoepidermoid carcinoma of the thymus extending into the skeletal muscle and pericardium with evidence of lymphovascular invasion. The patient received external beam radiation therapy and has remained disease-free for three years.

5.
J Magn Reson Imaging ; 52(2): 499-509, 2020 08.
Article in English | MEDLINE | ID: mdl-31950573

ABSTRACT

BACKGROUND: The poor prognosis of cardiac sarcoidosis (CS) underscores the need for risk stratification. PURPOSE: To investigate the prognostic significance of ventricular/myocardial remodeling features in sarcoidosis. STUDY TYPE: Retrospective. POPULATION: In all, 132 biopsy-proven sarcoidosis patients imaged from 2008 to 2018. The primary endpoint was a composite of cardiac mortality, new onset arrhythmias, hospitalization for heart failure, and device implantation. FIELD STRENGTH/SEQUENCE: No field strength or sequence restrictions. ASSESSMENT: Global and regional ventricular/myocardial remodeling features were assessed by standard volumetric measurements and automated function imaging postprocessing analysis. STATISTICAL TESTS: Student's t-test or Mann-Whitney test (chi2 test or Fisher's exact test for categorical variables) were used for comparisons. Cox-proportional hazards regression model, univariate /multivariate analyses, and receiver operating characteristic were performed to relate clinical/lab data, imaging parameters to the endpoints. RESULTS: Over a median follow-up of 40.7 (interquartile range 18.8-60.5) months, 41 (31.1%) patients developed adverse cardiac events. Abnormal left ventricular (LV) geometric remodeling alterations (measured by LV mass index and relative wall thickness) occurred 3.66-fold more frequently in patients with endpoints than patients without. The ratio of patients with endpoints increased as ventricular remodeling phenotype progressed. In patients with endpoints, regional myocardial wall thickness (RMWT) was significantly (P = 0.022) increased in six clustered LV segments located in the middle interventricular septum and basal/middle anterolateral walls. In all of the abnormal ventricular remodeling stages, patients with endpoints constantly had higher mean RMWT than those without. Among clinical, electrocardiographic, and imaging parameters, LV mass index (hazard ratio [HR] 1.010 95% confidence interval [CI] 1.002-1.018, P = 0.017) and mean RMWT (HR 3.482 95% CI 1.679-7.223, P = 0.001) were independently associated with endpoints. Sarcoidosis patients without this RMWT distribution pattern were significantly (P < 0.001) more likely to be free of the occurrence of subsequent cardiac events. DATA CONCLUSION: Regional myocardial remodeling characteristics are associated with subsequent adverse cardiac events in sarcoidosis. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:499-509.


Subject(s)
Sarcoidosis , Ventricular Function, Left , Humans , Predictive Value of Tests , Prognosis , Retrospective Studies , Risk Factors , Sarcoidosis/diagnostic imaging , Ventricular Remodeling
6.
Neuroophthalmology ; 43(3): 185-191, 2019 Jun.
Article in English | MEDLINE | ID: mdl-31312243

ABSTRACT

Castleman disease (CD) is a rare lymphoproliferative disorder that may present with various autoimmune, inflammatory, or neurologic syndromes. This is a case of a 21-year-old woman who presented with signs and symptoms of pseudotumour cerebri (PTC) who subsequently developed myasthenia gravis (MG), and was incidentally found to have a large mass in the posterior mediastinum. Upon resection, the mass was classified as unicentric CD involved with follicular dendritic cell sarcoma. Following treatment with IVIG in the setting of progressive weakness and dyspnea, she has had complete symptom resolution while maintained on a low dose of pyridostigmine for the last two years. There are 13 cases of MG and five cases of optic disc edema described as PTC associated with CD in the literature, but to our knowledge, this is the sole case reported of the intersection of all three conditions in one patient. Increased serum levels of interleukin-6 and vascular endothelial growth factor may provide clues as to the association of CD with these neurologic syndromes.

8.
Int J Cardiol ; 276: 1-7, 2019 Feb 01.
Article in English | MEDLINE | ID: mdl-30413307

ABSTRACT

BACKGROUND: In patients with acute anterior myocardial infarction (MI), sometimes an "apical ballooning" contractile dysfunction pattern that exceeds factual myocardial injury is identified in the ventriculography and bedside echocardiography. The hemodynamic consequences/sequela of this "Tako-tsobu effect" has not been well delineated. Of note, this anatomic imaging finding often misleads frontline physicians who assume reciprocal causation of persistent cardiac pump failure and ventricular pressure overload. METHODS AND RESULTS: Using real-time myocardial perfusion contrast echocardiography (MCE), we investigated myocardial (microvascular) perfusion in 60 patients after acute MI and coronary revascularization. Twenty-eight percent of the studied patients showed significantly mismatched myocardial perfusion and contractile defects. In these patients, an integrated imaging assessment with coronary angiography/ventriculography, deformation echocardiography, and MCE proved that the myocardial mechanic abnormalities significantly exceeded the defected perfusion areas. Compared with 72% of the patients without perfusion-contractility mismatch, apparently worse systolic functions (left ventricular ejection, wall motion score, and systolic longitudinal strain) in these patients did not change diastolic ventricular filling pressures (E/E' and E/A) or hemodynamic consequences/adverse events. Both systolic and diastolic functions in patients with perfusion-contractility mismatch appeared to be comparable with those in patients with Tako-tsubo syndrome. CONCLUSIONS: Real-time MCE identifies discrepant myocardial microvascular perfusion and mechanics in patients with acute MI. The "Tako-tsubo effect" in patients with perfusion-contractility mismatch does not cause diastolic filling pressure change or worse hemodynamic consequence/cardiac event.


Subject(s)
Echocardiography, Doppler/methods , Microcirculation , Myocardial Infarction/diagnostic imaging , Myocardial Perfusion Imaging/methods , Takotsubo Cardiomyopathy/diagnostic imaging , Aged , Female , Follow-Up Studies , Humans , Male , Microcirculation/physiology , Middle Aged , Myocardial Infarction/physiopathology , Pilot Projects , Takotsubo Cardiomyopathy/physiopathology
9.
J Thorac Dis ; 10(5): 3027-3038, 2018 May.
Article in English | MEDLINE | ID: mdl-29997970

ABSTRACT

BACKGROUND: Although morphological abnormalities of the heart appear to be remarkable, most patients with tako-tsubo cardiomyopathy (TTC) remain clinically stable. We investigate real time changes in the left ventricular (LV) and right ventricular (RV) mechanics and function to explore the mechanism to preserve hemodynamics. METHODS: With deformation and Doppler echocardiography, we evaluated myocardial mechanics and ventricular function/hemodynamics simultaneously in 103 consecutive TTC patients admitted from 01/01/2008 through 12/31/2015. The coronary angiography and left ventriculography were performed to rule out culprit coronary artery stenosis (CAS). We included 66 patients in a control group with matched age, sex, and risk factors for coronary artery disease (CAD), and 41 patients in a group of myocardial infarction induced cardiogenic shock, who required circulatory supporting devices to maintain hemodynamic stability. RESULTS: Although systolic myocardial strain in most of the LV segments was significantly impaired, 4 basal LV segments remained functionally active during acute stage of TTC. The impairment in the myocardial strain of the RV apex could extend to the middle segments, but basal RV systolic strain was also preserved. Despites comparable apical to basal strain gradients, LV and RV displayed discrepant functional/hemodynamic status. In contrast to LV, RV functional/hemodynamic parameters appeared to be hyper-dynamic. This unique RV strain pattern remained unchanged in patients with atypical (mid-LV cavity) TTC. In 41 patients with myocardial infarction induced cardiogenic shock, RV exhibited comparable mechanic and functional features with those in TTC patients. CONCLUSIONS: The identified LV and RV mechanic changes appear to support interventricular hemodynamic dependence during TTC, which may represent a universal rescue mechanism in a jeopardized or injured heart.

10.
Int J Cardiovasc Imaging ; 34(2): 251-262, 2018 Feb.
Article in English | MEDLINE | ID: mdl-28889326

ABSTRACT

The poor prognosis of cardiac sarcoidosis (CS) underscores the need for risk stratification. We evaluated 84 consecutive sarcoidosis patients who were referred for echocardiographic studies for cardiac symptoms or abnormal electrocardiograms. In 54 patients without previous diagnosis of CS or other known structural heart disease, 13 reached endpoints during (median) 24 months follow up. Significantly impaired peak systolic longitudinal strain in their original echocardiograms were identified in 13 of 17 left ventricular segments, clustering in the free wall, interventricular septum and apex. The regional (including 13 clustered segments) peak systolic longitudinal strain (RPSLS) were significantly impaired in patients with endpoints, compared with those without [(-11.4 ± 4.45) vs. (-18.7 ± 3.76) %, P < 0.00001]. Cox multivariate regression analysis revealed that RPSLS was independently associated with endpoints (HR 1.24; 95% CI 1.08-1.42, P = 0.002). Receiver operating characteristic curve suggested a cut-off RPSLS value of -15.0% (84.6% sensitivity and 86.8% specificity) to predict the occurrence of endpoints. Impaired RPSLS correlates with risk of adverse cardiac events in patients with extra-cardiac sarcoidosis.


Subject(s)
Cardiomyopathies/diagnostic imaging , Echocardiography , Myocardial Contraction , Sarcoidosis/diagnostic imaging , Ventricular Function, Left , Adult , Area Under Curve , Biomechanical Phenomena , Cardiomyopathies/physiopathology , Chi-Square Distribution , Disease Progression , Disease-Free Survival , Female , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Multivariate Analysis , Predictive Value of Tests , Proportional Hazards Models , ROC Curve , Reproducibility of Results , Retrospective Studies , Risk Factors , Sarcoidosis/physiopathology , Time Factors
11.
J Thorac Cardiovasc Surg ; 153(6): 1592-1597, 2017 06.
Article in English | MEDLINE | ID: mdl-28274562

ABSTRACT

OBJECTIVE: Cancer and Leukemia Group B 140503 is an ongoing, multicenter randomized trial assessing whether sublobar resection is equivalent to lobectomy for the treatment of stage I A non-small cell lung cancer (NSCLC) ≤2 cm in diameter. The objective of this report is to determine the reasons precluding intraoperative randomization. METHODS: From June 15, 2007, to March 22, 2013, 637 patients were preregistered to the trial. Three hundred eighty-nine were randomized successfully (61%), and 248 patients were not randomized (39%). We analyzed the reasons for nonrandomization among a subset of the nonrandomized patients (208) for whom additional data were available. RESULTS: Of these 208 patients, undiagnosed benign nodules (n =104, 16% of all registered patients) and understaging of NSCLC (n =45, 7% of all registered patients) were the dominant reasons precluding randomization. Granulomas represent one-quarter of the benign nodules. The understaged patients had unsuspected nodal metastases (n =28) or other more advanced NSCLC. The rate of randomization was significantly greater in those patients who had a preoperative biopsy (P <.001). CONCLUSIONS: In a carefully monitored cohort of patients with suspected small NSCLC ≤2 cm, a substantial number are misdiagnosed (benign nodules) or understaged. These patients may not have benefited from a thoracic surgical procedure. Preoperative biopsy significantly increased the rate of correct diagnosis. Preoperative biopsy of small suspected NSCLC will reduce the number of nontherapeutic or unnecessary thoracic procedures. Accuracy in preoperative diagnosis is increasingly important as more such small nodules are discovered through lung cancer screening.


Subject(s)
Carcinoma, Non-Small-Cell Lung/pathology , Lung Neoplasms/pathology , Patient Selection , Aged , Biopsy , Carcinoma, Non-Small-Cell Lung/surgery , Diagnostic Errors , Female , Humans , Lung Neoplasms/surgery , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Staging , Pneumonectomy/adverse effects , Pneumonectomy/methods , Predictive Value of Tests , Reproducibility of Results , Treatment Outcome , Tumor Burden , Unnecessary Procedures
12.
Acad Radiol ; 22(1): 33-49, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25442800

ABSTRACT

Quantitative imaging (QI) is increasingly applied in modern radiology practice, assisting in the clinical assessment of many patients and providing a source of biomarkers for a spectrum of diseases. QI is commonly used to inform patient diagnosis or prognosis, determine the choice of therapy, or monitor therapy response. Because most radiologists will likely implement some QI tools to meet the patient care needs of their referring clinicians, it is important for all radiologists to become familiar with the strengths and limitations of QI. The Association of University Radiologists Radiology Research Alliance Quantitative Imaging Task Force has explored the clinical application of QI and summarizes its work in this review. We provide an overview of the clinical use of QI by discussing QI tools that are currently used in clinical practice, clinical applications of these tools, approaches to reporting of QI, and challenges to implementing QI. It is hoped that these insights will help radiologists recognize the tangible benefits of QI to their patients, their referring clinicians, and their own radiology practice.


Subject(s)
Biomarkers/analysis , Image Interpretation, Computer-Assisted/methods , Molecular Diagnostic Techniques/methods , Molecular Imaging/methods , Molecular Probe Techniques , Molecular Probes , Animals , Evaluation Studies as Topic , Humans
13.
Acad Radiol ; 22(1): 25-32, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25481515

ABSTRACT

Academic radiology is poised to play an important role in the development and implementation of quantitative imaging (QI) tools. This article, drafted by the Association of University Radiologists Radiology Research Alliance Quantitative Imaging Task Force, reviews current issues in QI biomarker research. We discuss motivations for advancing QI, define key terms, present a framework for QI biomarker research, and outline challenges in QI biomarker development. We conclude by describing where QI research and development is currently taking place and discussing the paramount role of academic radiology in this rapidly evolving field.


Subject(s)
Biomarkers/analysis , Image Interpretation, Computer-Assisted/methods , Molecular Diagnostic Techniques/methods , Molecular Imaging/methods , Molecular Probe Techniques , Molecular Probes , Animals , Humans
14.
Clin Lung Cancer ; 15(4): 302-6, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24954230

ABSTRACT

BACKGROUND: Obtaining a tissue diagnosis has traditionally been standard practice before initiating therapy for early-stage non-small-cell lung cancer (NSCLC). In several recent studies from Europe and Asia, a substantial proportion of patients have received stereotactic body radiation therapy (SBRT) based only on the imaging characteristics of the suspicious lesion. The underlying assumption is that the risk of percutaneous needle biopsy may outweigh the benefits in a population that generally has underlying pulmonary dysfunction and other medical comorbidity. Nevertheless, there is limited information regarding biopsy-related complication rates in high-risk patients with early-stage NSCLC who are treated with SBRT. MATERIALS AND METHODS: This was a retrospective review of outcomes after biopsy in patients treated with SBRT. Complications of percutaneous core needle biopsy were analyzed in relation to patient and tumor characteristics. Each biopsy event was analyzed independently for patients with multiple biopsies. RESULTS: A total of 112 percutaneous biopsies were performed in 103 patients. Pneumothorax of any degree was observed in 40 patients (35%) (95% CI, 27%-45%), and 12 patients (10.7%) had a clinically significant pneumothorax requiring chest tube placement (95% CI, 6%-18%). The time to first fraction of SBRT was not different in patients who had a pneumothorax or placement of a chest tube. On multivariate analysis, age, performance status, smoking history, pack-years of smoking, chronic obstructive pulmonary disease history, and forced expiratory volume in the first second of expiration were not statistically significantly associated with chest tube placement. CONCLUSION: Computed tomography-guided needle biopsy in a primarily medically inoperable patient population is safe, with an acceptable degree of complications.


Subject(s)
Biopsy, Large-Core Needle , Carcinoma, Non-Small-Cell Lung/diagnosis , Image-Guided Biopsy , Lung Neoplasms/diagnosis , Lung/pathology , Aged , Aged, 80 and over , Biopsy, Large-Core Needle/adverse effects , Carcinoma, Non-Small-Cell Lung/pathology , Carcinoma, Non-Small-Cell Lung/radiotherapy , Chest Tubes/statistics & numerical data , Female , Humans , Image-Guided Biopsy/adverse effects , Lung/diagnostic imaging , Lung Neoplasms/pathology , Lung Neoplasms/radiotherapy , Male , Middle Aged , Neoplasm Staging , Pneumothorax/etiology , Radiosurgery , Retrospective Studies , Risk , Tomography, X-Ray Computed
15.
Med Phys ; 41(6): 061904, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24877815

ABSTRACT

PURPOSE: To introduce a method of estimating cardiac output from the dynamic pulmonary circulation time CT that is primarily used to determine the optimal time window of CT pulmonary angiography (CTPA). METHODS: Dynamic pulmonary circulation time CT series, acquired for eight patients, were retrospectively analyzed. The dynamic CT series was acquired, prior to the main CTPA, in cine mode (1 frame/s) for a single slice at the level of the main pulmonary artery covering the cross sections of ascending aorta (AA) and descending aorta (DA) during the infusion of iodinated contrast. The time series of contrast changes obtained for DA, which is the downstream of AA, was assumed to be related to the time series for AA by the convolution with a delay function. The delay time constant in the delay function, representing the average time interval between the cross sections of AA and DA, was determined by least square error fitting between the convoluted AA time series and the DA time series. The cardiac output was then calculated by dividing the volume of the aortic arch between the cross sections of AA and DA (estimated from the single slice CT image) by the average time interval, and multiplying the result by a correction factor. RESULTS: The mean cardiac output value for the six patients was 5.11 (l/min) (with a standard deviation of 1.57 l/min), which is in good agreement with the literature value; the data for the other two patients were too noisy for processing. CONCLUSIONS: The dynamic single-slice pulmonary circulation time CT series also can be used to estimate cardiac output.


Subject(s)
Cardiac Output , Pulmonary Circulation , Tomography, X-Ray Computed/methods , Adult , Aged , Angiography/methods , Aortography/methods , Artifacts , Blood Pressure , Heart Rate , Humans , Least-Squares Analysis , Male , Middle Aged , Organ Size , Pulmonary Artery/diagnostic imaging , Retrospective Studies , Signal Processing, Computer-Assisted , Time Factors
16.
Chest ; 144(1): 323-327, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23880681

ABSTRACT

Hut lung is a pneumoconiosis caused by exposure to smoke derived from biomass fuels used for cooking in poorly ventilated huts. We report, to our knowledge, the first analysis of the dust deposited in the lungs in hut lung by scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM/EDS). A Bhutanese woman presented with shortness of breath and an abnormal chest radiograph. Chest CT scan showed innumerable tiny bilateral upper lobe centrilobular nodules. Transbronchial biopsy revealed mild interstitial fibrosis with heavy interstitial deposition of black dust. SEM/EDS showed that the dust was carbonaceous, with smaller yet substantial numbers of silica and silicate particles. Additional history revealed use of a wood/coal-fueled stove in a small, poorly ventilated hut for 45 years. The possibility of hut lung should be considered in women from countries where use of biomass-fueled stoves for cooking is common. Our findings support the classification of this condition as a mixed-dust pneumoconiosis.


Subject(s)
Carbon , Cooking , Pneumoconiosis/diagnosis , Pneumoconiosis/etiology , Silicon Dioxide , Bhutan , Biomass , Biopsy , Female , Humans , Lung/chemistry , Lung/pathology , Lung/ultrastructure , Microscopy, Electron, Scanning , Middle Aged , Pneumoconiosis/pathology , Spectrum Analysis , Tomography, X-Ray Computed
17.
Pediatr Radiol ; 42(5): 527-35, 2012 May.
Article in English | MEDLINE | ID: mdl-22430480

ABSTRACT

BACKGROUND: Patient organ doses may be estimated from CTDI values. More accurate estimates may be obtained by measuring KERMA (Kinetic Energy Released in Matter) in anthropomorphic phantoms and referencing these values to free-in-air X-ray intensity. OBJECTIVE: To measure KERMA ratios (R(K)) in pediatric phantoms at CT. MATERIALS & METHODS: CT scans produce an air KERMA K in a phantom and an air KERMA K(CT) at isocenter. KERMA ratios (R(K)) are defined as (K/K(CT)), measured using TLD chips in phantoms representing newborns to 10-year-olds. RESULTS: R(K) in the newborn is approximately constant. For the other phantoms, there is a peak R(K) value in the neck. The median R(K) values for the GE scanner at 120 kV were 0.92, 0.83, 0.77 and 0.76 for newborns, 1-year-olds, 5-year-olds and 10-year-olds, respectively. Organ R(K) values were 0.91 ± 0.04, 0.84 ± 0.07, 0.74 ± 0.09 and 0.72 ± 0.10 in newborns, 1-year-olds, 5-year-olds and 10-year-olds, respectively. At 120 kV, a Siemens Sensation 16 scanner had R(K) values 5% higher than those of the GE LightSpeed Ultra. CONCLUSION: KERMA ratios may be combined with air KERMA measurements at the isocenter to estimate organ doses in pediatric CT patients.


Subject(s)
Phantoms, Imaging , Radiation Dosage , Radiometry/methods , Tomography, X-Ray Computed , Child , Child, Preschool , Humans , Infant , Infant, Newborn
18.
Med Phys ; 38(10): 5362-9, 2011 Oct.
Article in English | MEDLINE | ID: mdl-21992356

ABSTRACT

PURPOSE: To estimate in-patient KERMA for specific organs in computed tomography (CT) scanning using ratios to isocenter free-in-air KERMA obtained using a Rando phantom. METHOD: A CT scan of an anthropomorphic phantom results in an air KERMA K at a selected phantom location and air kerma K(CT) at the CT scanner isocenter when the scan is repeated in the absence of the phantom. The authors define the KERMA ratio (R(K)) as K∕ K(CT), which were experimentally determined in a Male Rando Phantom using lithium fluoride chips (TLD-100). R(K) values were obtained for a total of 400 individual point locations, as well as for 25 individual organs of interest in CT dosimetry. CT examinations of Rando were performed on a GE LightSpeed Ultra scanner operated at 80 kV, 120 kV, and 140 kV, as well as a Siemens Sensation 16 operated at 120 kV. RESULTS: At 120 kV, median R(K) values for the GE and Siemens scanners were 0.60 and 0.64, respectively. The 10th percentile R(K) values ranged from 0.34 at 80 kV to 0.54 at 140 kV, and the 90th percentile R(K) values ranged from 0.64 at 80 kV to 0.78 at 140 kV. The average R(K) for the 25 Rando organs at 120 kV was 0.61 ± 0.08. Average R(K) values in the head, chest, and abdomen showed little variation. Relative to R(K) values in the head, chest, and abdomen obtained at 120 kV, R(K) values were about 12% lower in the pelvis and about 58% higher in the cervical spine region. Average R(K) values were about 6% higher on the Siemens Sensation 16 scanner than the GE LightSpeed Ultra. Reducing the x-ray tube voltage from 120 kV to 80 kV resulted in an average reduction in R(K) value of 34%, whereas increasing the x-ray tube voltage to 140 kV increased the average R(K) value by 9%. CONCLUSIONS: In-patient to isocenter relative KERMA values in Rando phantom can be used to estimate organ doses in similar sized adults undergoing CT examinations from easily measured air KERMA values at the isocenter (free in air). Conversion from in-patient air KERMA values to tissue dose would require the use of energy-appropriate conversion factors.


Subject(s)
Thermoluminescent Dosimetry/methods , Tomography, X-Ray Computed/methods , Adult , Air , Algorithms , Body Size , Humans , Male , Monte Carlo Method , Phantoms, Imaging , Radiometry , Tissue Distribution , Tomography Scanners, X-Ray Computed , Water/chemistry , Whole Body Imaging/methods , X-Rays
19.
Thorax ; 65(9): 833-5, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20805183

ABSTRACT

A pathological diagnosis of pulmonary Langerhans cell histiocytosis (PLCH) usually requires a surgical lung biopsy. To date, diagnosis of PLCH by core needle biopsy has not been reported. Three cases are presented of PLCH diagnosed by CT-guided core biopsy in adult female smokers found to have multiple small bilateral lung nodules. The nodules biopsied were 5 mm, 7 mm and 1 cm in size, and showed interstitial expansion by Langerhans cells and eosinophils. CT-guided core biopsy should be considered as one of the less invasive techniques by which a pathological diagnosis of PLCH can be established.


Subject(s)
Biopsy, Needle/methods , Histiocytosis, Langerhans-Cell/pathology , Lung Diseases/pathology , Aged , Female , Histiocytosis, Langerhans-Cell/diagnostic imaging , Humans , Lung Diseases/diagnostic imaging , Middle Aged , Radiography, Interventional/methods , Tomography, X-Ray Computed/methods
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