Showing papers in "Radiology in 2009"
TL;DR: While most patients accrue low radiation-induced cancer risks, a subgroup is potentially at higher risk due to recurrent CT imaging, and Cumulative CT radiation exposure added incrementally to baseline cancer risk in the cohort.
Abstract: Purpose: To estimate cumulative radiation exposure and lifetime attributable risk (LAR) of radiation-induced cancer from computed tomographic (CT) scanning of adult patients at a tertiary care academic medical center. Materials and Methods: This HIPAA-compliant study was approved by the institutional review board with waiver of informed consent. The cohort comprised 31 462 patients who underwent diagnostic CT in 2007 and had undergone 190 712 CT examinations over the prior 22 years. Each patient's cumulative CT radiation exposure was estimated by summing typical CT effective doses, and the Biological Effects of Ionizing Radiation (BEIR) VII methodology was used to estimate LAR on the basis of sex and age at each exposure. Billing ICD9 codes and electronic order entry information were used to stratify patients with LAR greater than 1%. Results: Thirty-three percent of patients underwent five or more lifetime CT examinations, and 5% underwent between 22 and 132 examinations. Fifteen percent received estimat...
893 citations
TL;DR: The U.S. National Council on Radiation Protection and Measurements and United Nations Scientific Committee on Effects of Atomic Radiation each conducted respective assessments of all radiation sources in the United States and worldwide and to compare the results with historical information.
Abstract: The per-capita annual effective radiation dose from medical procedures in the United States is among the highest in the world and is estimated to have increased sixfold from about 0.5 mSv in 1980 to 3.0 mSv in 2006.
767 citations
TL;DR: ARFI imaging is a promising US-based method for assessing liver fibrosis in chronic viral hepatitis, with diagnostic accuracy comparable to that of TE in this preliminary study.
Abstract: In our pilot study, the results of US-based acoustic radiation force impulse imaging were comparable to those of transient elastography and FibroTest scoring for the noninvasive measurement of liver fibrosis.
612 citations
TL;DR: The carcinogenic risk induced by low doses of ionizing radiation is controversial and cannot be assessed with epidemiologic methods alone because at low doses the data are imprecise and often conflicting.
Abstract: The carcinogenic risk induced by low doses of ionizing radiation is controversial. It cannot be assessed with epidemiologic methods alone because at low doses the data are imprecise and often conflicting. Since the 1970s, the radiation protection community has estimated the risk of low doses by means of extrapolation from the risk assessed at high doses, generally by using the linear no-threshold (LNT) model.
The LNT relationship implies proportionality between dose and cancer risk. This approach is based on one set of data and two hypotheses: (a) The relationship between dose and DNA damage in vivo seems linear from 1 mGy to 100 Gy with use of H2AX foci as a marker for DNA double-strand breaks (DSBs)—however, this marker is not specific (1); (b) each DSB is hypothesized to have the same probability of inducing cell transformation, irrespective of the quantity of DSBs present simultaneously in the cell; and (c) each transformed cell is hypothesized to have the same probability of developing into an invasive cancer, irrespective of the dose delivered to the tissue. The advances during the past 2 decades in radiation biology, the understanding of carcinogenesis, and the discovery of defenses against carcinogenesis challenge the LNT model, which appears obsolete (2–6).
Life developed in a bath of ionizing radiation and solar ultraviolet radiation and created aerobic organisms requiring (a) defenses against the metabolically induced reactive oxygen species, (b) DNA repair, and (c) elimination of damaged cells. Several sets of data show the efficacy of these defenses to be much higher at low than at high doses and for fractionated or protracted irradiation than for acute irradiation.
The LNT model was introduced as a concept to facilitate radiation protection (7). But the use of this model led to the claim that even the smallest dose (one electron traversing a cell) may initiate carcinogenesis—for instance, from diagnostic x-ray sources (8,9). This claim is highly hypothetical and has resulted in medical, economic, and other societal harm.
The French Academies report (10) concluded that the LNT model and its use for assessing the risks associated with low doses are not based on scientific evidence. In contrast, the Biological Effects of Ionizing Radiation (BEIR) VII report (11) and that of the International Commission on Radiological Protection (ICRP) (12) recommended the use of the LNT model. We wish to update this debate by using recent radiation biologic and epidemiologic data.
483 citations
TL;DR: Whole-body PET/CT scanning is accompanied by substantial radiation dose and cancer risk and examinations should be clinically justified, and measures should be taken to reduce the dose.
Abstract: Purpose: To estimate the radiation dose from whole-body fluorine 18 (18F)-fluorodeoxyglucose (FDG) positron emission tomographic (PET)/computed tomographic (CT) studies and to evaluate the induced cancer risk to U.S. and Hong Kong populations. Materials and Methods: Fluorine 18–FDG PET/CT studies obtained by using a 64-detector CT unit and one of three CT protocols were evaluated. CT protocol A consisted of 120 kV; rotation time, 0.5 second; pitch, 0.984; 100–300 mA; and noise level, 20. CT protocol B was the same as A, except for a fixed tube current of 250 mA. CT protocol C consisted of 140 kV; rotation time, 0.5 second; pitch, 0.984; 150–350 mA; and noise level, 3.5. CT doses were measured in a humanoid phantom equipped with thermoluminescent dosimeters. Doses from 18F-FDG PET scanning were estimated by multiplying the 18F-FDG radioactivity (370 MBq) with dose coefficients. Effective doses were calculated according to International Commission on Radiological Protection publication 103. Lifetime attribu...
452 citations
TL;DR: In patients with renal masses, DE CT can provide high-quality VNE data sets, which are a reasonable approximation of TNE data set, and integration of DE scanning into a renal mass protocol will lower radiation exposure by 35%.
Abstract: Our results show that in addition to contrast-enhanced imaging, dual-energy multidetector CT can provide virtually unenhanced data sets,that are a reasonable approximation of true unenhanced multidetector CT data sets at a dose less than that required for two acquisitions performed separately.
380 citations
TL;DR: Because MR enterography has a diagnostic effectiveness comparable to that of CT enterography, this technique has potential to be used as a radiation-free alternative for evaluation of patients with CD.
Abstract: Purpose: To prospectively compare the accuracy of computed tomographic (CT) and magnetic resonance (MR) enterography and small-bowel follow-through (SBFT) examination for detection of active small-bowel inflammation and extraenteric complications in patients with Crohn disease (CD). Materials and Methods: The institutional review board approved the study protocol; informed consent was obtained from all participants. Thirty-one consecutive patients who had CD or who were suspected of having CD underwent CT and MR enterography, SBFT, and ileocolonoscopy. Two independent readers reviewed CT and MR enterographic and SBFT images for presence of active terminal ileitis and extraenteric complications. Accuracy values of CT and MR enterography and SBFT for identification of active terminal ileitis were evaluated with the receiver operating characteristic method, with ileocolonoscopic findings as the reference standard. Sensitivity values of CT and MR enterography and SBFT for detection of extraenteric complicatio...
366 citations
TL;DR: The transition from normal cognition to AD is associated with dynamic pathologic processes in the brain, and this is reflected by both decreases and increases in rCBF, which suggest a cellular and vascular compensatory process associated with incipient AD.
Abstract: Purpose: To examine regional cerebral blood flow (rCBF) in incident mild cognitive impairment (MCI) and Alzheimer disease (AD) by using continuous arterial spin-labeling (CASL) magnetic resonance (MR) imaging. Materials and Methods: This study was approved by the local institutional review board and was compliant with HIPAA regulations. Informed consent was obtained. rCBF was measured in 38 control subjects, 29 MCI patients, and 37 AD patients who were participating in a longitudinal epidemiologic study. Multisection CASL MR imaging with alternating single and double adiabatic inversion pulses and ramp-sampled echo-planar imaging were performed to acquire 19 contiguous axial sections. Voxel-level rCBF was compared among groups by using an analysis of variance design; clusters of voxels with significant group differences were identified. Multiple regression models controlled for age, sex, and presence of hypertension and related the mean rCBF in those clusters to the presence of MCI and AD. Results: MCI an...
344 citations
TL;DR: Findings suggest that DSC perfusion MR imaging may be used to differentiate recurrent GBM from EBRT-induced radiation necrosis.
Abstract: In this study, we showed that quantitative measurement of hemodynamic values derived from T2*-weighted dynamic susceptibility-weighted contrast material–enhanced MR imaging results can be used to distinguish recurrent glioblastoma multiforme from external beam radiation therapy–induced necrosis.
343 citations
TL;DR: For bevacizumab-treated patients, pretreatment ADC more accurately stratified 6-month progression-free survival than did change in enhancing tumor volume at first follow-up (73% vs 58% accuracy, P = .034).
Abstract: Purpose: To determine if apparent diffusion coefficient (ADC) histogram analysis can stratify progression-free survival in patients with recurrent glioblastoma multiforme (GBM) prior to bevacizumab treatment. Materials and Methods: The study was approved by the institutional review board and was HIPAA compliant; informed consent was obtained. Bevacizumab-treated and control patients (41 per cohort) diagnosed with recurrent GBM were analyzed by using whole enhancing tumor ADC histograms with a two normal distribution mixture fitting curve on baseline (pretreatment) magnetic resonance (MR) images to generate ADC classifiers, including the overall mean ADC as well as the mean ADC from the lower curve (ADCL). Overall and 6-month progression-free survival (as defined by the Macdonald criteria) was determined by using Cox proportional hazard ratios and the Kaplan-Meier method with log-rank test. Results: For bevacizumab-treated patients, the hazard ratio for progression by 6 months in patients with less than ve...
327 citations
TL;DR: Adding DW MR imaging to conventional MR Imaging yields better diagnostic accuracy than use of conventional MR imaging alone in the evaluation of CR to neoadjuvant CRT in patients with locally advanced rectal cancer.
Abstract: Use of additional diffusion-weighted MR imaging yields better diagnostic accuracy than does use of conventional MR imaging alone in the evaluation of complete response to neoadjuvant combined chemotherapy and radiation therapy in patients with locally advanced rectal cancer.
TL;DR: Improved accuracy in the diagnosis of CTS is revealed with the Delta CSA compared with the accuracy of the diagnosis determined with the CSAc, which is smaller than that in patients and in asymptomatic wrists.
Abstract: Purpose: To improve accuracy in the diagnosis of carpal tunnel syndrome (CTS) by comparing cross-sectional area (CSA) measurements of the median nerve obtained at the level of the carpal tunnel (CSAc) with those obtained more proximally (CSAp), at the level of the pronator quadratus muscle. Materials and Methods: The study protocol was approved by the institutional review board, and all subjects gave written informed consent. One hundred wrists of 68 consecutive patients with CTS (16 men, 52 women; mean age, 57.9 years; range, 25–85 years) and 93 wrists of 58 healthy volunteers (16 male, 42 female; mean age, 55.1 years; range, 17–85 years) were examined with ultrasonography (US). Electrodiagnostic test results confirmed the diagnosis of CTS in all 68 patients. The US examiner was blinded to these test results. The CSA of the median nerve was measured at the carpal tunnel and proximal levels, and the difference between CSAc and CSAp (ΔCSA) was calculated for each wrist. Results: The mean CSAc in healthy vo...
TL;DR: In this article, the authors evaluated the cost effectiveness of CT in the setting of acute appendicitis, diverticulitis, and cholecystitis and concluded that CT is more accurate and informative in this setting as well.
Abstract: Acute abdominal pain may be caused by a myriad of diagnoses, including acute appendicitis, diverticulitis, and cholecystitis. Imaging plays an important role in the treatment management of patients because clinical evaluation results can be inaccurate. Performing computed tomography (CT) is most important because it facilitates an accurate and reproducible diagnosis in urgent conditions. Also, CT findings have been demonstrated to have a marked effect on the management of acute abdominal pain. The cost-effectiveness of CT in the setting of acute appendicitis was studied, and CT proved to be cost-effective. CT can therefore be considered the primary technique for the diagnosis of acute abdominal pain, except in patients clinically suspected of having acute cholecystitis. In these patients, ultrasonography (US) is the primary imaging technique of choice. When costs and ionizing radiation exposure are primary concerns, a possible strategy is to perform US as the initial technique in all patients with acute abdominal pain, with CT performed in all cases of nondiagnostic US. The use of conventional radiography has been surpassed; this examination has only a possible role in the setting of bowel obstruction. However, CT is more accurate and more informative in this setting as well. In cases of bowel perforation, CT is the most sensitive technique for depicting free intraperitoneal air and is valuable for determining the cause of the perforation. Imaging is less useful in cases of bowel ischemia, although some CT signs are highly specific. Magnetic resonance (MR) imaging is a promising alternative to CT in the evaluation of acute abdominal pain and does not involve the use of ionizing radiation exposure. However, data on the use of MR imaging for this indication are still sparse.
TL;DR: There is little epidemiologic or biologic evidence for these for cancer risks of low doses of ionizing radiation, and risks in moderate- and low-dose medically and occupationally exposed groups are generally consistent with those in the LSS.
Abstract: Deterministic and stochastic effects associated with high-dose ionizing radiation (x-ray) exposure have been known for almost as long as ionizing radiation itself (1–3). At lower doses, radiation risks are primarily stochastic effects, in particular, somatic effects (cancer) rather than the deterministic effects characteristic of higher-dose exposure (4–6). In contrast to deterministic effects, for stochastic effects, scientific committees generally assume that at sufficiently low doses there is a positive linear component to the dose response—that is, that there is no threshold (4–6). This does not preclude there being higher-order (eg, quadratic) powers of dose in the dose response that may be of importance at higher doses. It is on this basis that models linear (or linear-quadratic) in dose are often used to extrapolate the experience of the Japanese atomic bomb survivors (who were typically exposed at a high dose rate to moderate doses [average, 0.1 Sv]) to estimate risks from low doses and low dose rates (4–6). Most population-based cancer risk estimates are based primarily on the Japanese atomic bomb survivor Life Span Study (LSS) cohort data (4–6). However, evidence of excess risks comes from a large number of other studies as well.
In the parallel editorial (7), evidence is presented for possible real (or at least “practical”) thresholds or “hormetic” (beneficial) effects of low doses of ionizing radiation. As we summarize here, and in contrast to the arguments of Tubiana et al (7), we judge that there is little epidemiologic or biologic evidence for these for cancer. The arguments are of three forms: (a) assessment of the degree of curvature in the cancer dose response within the Japanese atomic bomb survivors and other exposed groups (in particular, departure from linear or linear-quadratic curvature), (b) consistency of risks between the Japanese and other moderate- and low-dose cohorts, and (c) assessment of biologic data on mechanisms.
Most of the information on radiation-induced cancer risk comes from (a) the Japanese atomic bomb survivors, (b) medically exposed populations, (c) occupationally exposed groups, and (d) environmentally exposed groups (6). In the higher-dose radiation therapy studies, where doses received are very much higher than in the LSS, sometimes in the range at which cell sterilization occurs, excess cancer risks per unit dose tend to be less than in comparable subsets of the LSS (8,9). However, as we show, risks in moderate- and low-dose medically and occupationally exposed groups are generally consistent with those in the LSS.
TL;DR: Several MR imaging features might be used for detecting triple-negative breast cancer, and very high intratumoral signal intensity on T2-weighted MR images was significantly associated with triple- negative breast cancer.
Abstract: Purpose: To retrospectively evaluate the magnetic resonance (MR) imaging findings of “triple-negative” breast cancer (ie, cancer that is estrogen receptor [ER] negative, progesterone receptor [PR] negative, and human epidermal growth factor receptor 2 [HER2] negative) and to compare them with those of breast cancers that are ER positive, PR positive, and HER2 negative. Materials and Methods: Institutional review board approval and informed consent were obtained. The MR imaging findings in 176 randomly assigned women (mean age, 56 years; range, 29–87 years) with surgically confirmed triple-negative breast cancers (n = 59) or ER-positive/PR-positive/HER2-negative breast cancers (n = 117) were reviewed. MR imaging findings included tumor shape, margin, internal enhancement, and size, as well as intratumoral signal intensity that was stronger than or almost the same as that of water or vessels on T2-weighted MR images. The MR imaging findings were compared with the pathologic findings. Results: High histologi...
TL;DR: Chest CT scans are well reproducible and changes in unidimensional lesion size of 8% or greater exceed the measurement variability of the computer method and can be considered significant when estimating the outcome of therapy in a patient.
Abstract: Our findings will help reveal variations in the unidimensional, bidimensional, and volumetric measurements on modern CT scans and thus be valuable in detecting biologically relevant tumor changes in the assessment of therapy response in non–small cell lung cancer.
TL;DR: Semiautomated, individually specific quantitative MR imaging methods can be used to identify a pattern of regional atrophy in MCI that is predictive of clinical decline and structural loss that may aid in prediction of patient prognosis and increase the efficiency of clinical trials.
Abstract: Purpose: To use structural magnetic resonance (MR) images to identify a pattern of regional atrophy characteristic of mild Alzheimer disease (AD) and to investigate whether presence of this pattern prospectively can aid prediction of 1-year clinical decline and increased structural loss in mild cognitive impairment (MCI). Materials and Methods: The study was conducted with institutional review board approval and compliance with HIPAA regulations. Written informed consent was obtained from each participant. High-throughput volumetric segmentation and cortical surface reconstruction methods were applied to MR images from 84 subjects with mild AD, 175 with MCI, and 139 healthy control (HC) subjects. Stepwise linear discriminant analysis was used to identify regions that best can aid discrimination of HC subjects from subjects with AD. A classifier trained on data from HC subjects and those with AD was applied to data from subjects with MCI to determine whether presence of phenotypic AD atrophy at baseline wa...
TL;DR: MW ablation is a well-tolerated technique with an acceptably low rate of major complications for treatment of malignant liver tumors and use of a cooled-shaft antenna, as well as fewer MW sessions, may help minimize major complications.
Abstract: Purpose: To report the complications for percutaneous microwave (MW) ablation for the treatment of malignant liver tumors and the possible risk factors for complications in a large series of patients. Materials and Methods: The study was approved by the institutional review board; informed consent was waived because of the retrospective design. Over a 13-year period, 1136 patients with 1928 malignant liver tumors underwent ultrasonographically guided percutaneous MW ablation (583 with a noncooled-shaft antenna and 553 with a cooled-shaft antenna). A total of 3697 MW ablation sessions (average, 1.8 sessions per patient) were performed. Mortality and treatment-related major and minor complications were documented. Data were subsequently analyzed to determine whether the major complication rate was related to antenna type, tumor size, tumor location, or number of MW sessions. Results: Two deaths not directly attributable to MW ablation were encountered. Major complications occurred in 30 (2.6%) patients and ...
TL;DR: DW imaging performed with ADC(b0-1000) values had higher accuracy than turbo spin-echo MR imaging in nodal staging, providing added value in the detection of subcentimeter nodal metastases.
Abstract: Purpose: To evaluate diffusion-weighted (DW) magnetic resonance (MR) imaging, as compared with turbo spin-echo MR imaging, for the detection of nodal metastases in head and neck squamous cell carcinoma (HNSCC). Materials and Methods: The study was approved by the ethics committee, and patients gave written informed consent. Before undergoing surgery, 33 consecutive patients underwent 1.5-T MR imaging, including DW imaging performed with a wide range of b values (0–1000 sec/mm2). The apparent diffusion coefficients (ADCs) of lymph nodes 4 mm or greater in short-axis diameter depicted on images obtained with b values of 0 and 1000 sec/mm2 were calculated. After topographic correlation, the lymph nodes were evaluated microscopically with prekeratin immunostaining. The optimal ADC thresholds for discriminating between metastatic and benign lymph nodes were determined. The sensitivity, specificity, and accuracy of DW imaging were calculated separately—on per-lymph-node and per-neck-level bases—for all lymph no...
TL;DR: Relaxation- and interference-corrected fat quantification at low-flip-angle multiecho GRE MR imaging provides high diagnostic and fat-grading accuracy in nonalcoholic fatty liver disease (NAFLD).
Abstract: Purpose: To assess the accuracy of four fat quantification methods at low-flip-angle multiecho gradient-recalled-echo (GRE) magnetic resonance (MR) imaging in nonalcoholic fatty liver disease (NAFLD) by using MR spectroscopy as the reference standard. Materials and Methods: In this institutional review board–approved, HIPAA-compliant prospective study, 110 subjects (29 with biopsy-confirmed NAFLD, 50 overweight and at risk for NAFLD, and 31 healthy volunteers) (mean age, 32.6 years ± 15.6 [standard deviation]; range, 8–66 years) gave informed consent and underwent MR spectroscopy and GRE MR imaging of the liver. Spectroscopy involved a long repetition time (to suppress T1 effects) and multiple echo times (to estimate T2 effects); the reference fat fraction (FF) was calculated from T2-corrected fat and water spectral peak areas. Imaging involved a low flip angle (to suppress T1 effects) and multiple echo times (to estimate T2* effects); imaging FF was calculated by using four analysis methods of progressiv...
TL;DR: DW images provided useful information for evaluating the T stage of bladder cancer, particularly in differentiating T1 or lower tumors from T2 or higher tumors.
Abstract: Purpose: To prospectively evaluate the ability of diffusion-weighted (DW) magnetic resonance (MR) imaging to be used to determine the T stage of bladder cancer and to measure the correlation between the apparent diffusion coefficient (ADC) and histologic grade. Materials and Methods: This study was approved by the local institutional review board. All patients gave written informed consent. Forty patients with a total of 52 bladder tumors underwent MR imaging that included DW imaging. Histologic grade was determined for all tumors. Two radiologists interpreted four image sets (ie, T2-weighted images alone, T2-weighted plus DW images, T2-weighted plus dynamic contrast agent–enhanced images, all three image types together). Conventional criteria were used for interpreting T2-weighted and contrast-enhanced images. For DW images, new staging criterion developed on the basis of the hypothesis that tumors, submucosal tissue, and muscles show high, low, and intermediate signal intensity, respectively, was used. ...
TL;DR: In this article, the diagnostic performance of diffusion-weighted (DW) imaging with that of contrast materialenhanced (CE) MR imaging was compared for the characterization of renal lesions, with MR follow-up and histopathologic analysis as the reference standards.
Abstract: Purpose: To compare the diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) imaging with that of contrast material–enhanced (CE) MR imaging and to assess the performance of these examinations combined for the characterization of renal lesions, with MR follow-up and histopathologic analysis as the reference standards Materials and Methods: The institutional review board waived the requirement of informed patient consent for this retrospective HIPAA-compliant study One hundred nine renal lesions in 64 patients (46 men, 18 women; mean age, 607 years) were evaluated with CE MR imaging and breath-hold DW imaging performed with various b values Renal lesions were characterized with use of CE MR criteria, and apparent diffusion coefficients (ADCs) were measured The ADCs of benign and malignant lesions were compared at Mann-Whitney testing Receiver operating characteristic (ROC) analysis was performed to assess the accuracy of DW imaging and CE MR imaging in the diagnosis of renal cell
TL;DR: Impaired executive function following mTBI is associated with axonal injury involving the DLPFC, and multiple clusters of lower frontal white matter FA, including the dorsolateral prefrontal cortex (DLPFC), were present in patients.
Abstract: Our study was designed to determine whether frontal white matter diffusion abnormalities can help predict acute executive function impairment after mild traumatic brain injury.
TL;DR: In patients with intraarterial administration and renal insufficiency, iodxanol is associated with a reduced risk of CIN compared with iohexol, whereas no significant difference between iodixanol and other LOCM could be found.
Abstract: Purpose: To compare the nephrotoxicity of iso-osmolar iodixanol with that of nonionic low-osmolar contrast media (CM) (LOCM) in randomized clinical trials. Materials and Methods: This meta-analysis was conducted with a systematic search of MEDLINE, EMBASE, BIOSIS, Web of Science, ISI Web of Knowledge, Current Contents Medizin, Cochrane Library (until August 2007), trial registers, conference proceedings, and reference lists to identify studies and with requests from all manufacturers of CM for unidentified studies. Randomized controlled trials assessing serum creatinine levels before and after intravascular application of iodixanol or LOCM were included. The primary outcome measures were the incidence of contrast medium–induced nephropathy (CIN) and change in serum creatinine levels. Results: Twenty-five trials were included. Iodixanol did not significantly reduce the risk of CIN (relative risk [RR], 0.80; 95% confidence interval [CI]: 0.61, 1.04; weighted mean difference in serum creatinine increase, 0.0...
TL;DR: Recognition of the potential association between subsolid nodules and peripheral adenocarcinomas requires a review of current guidelines for the management of these lesions, further necessitated by a differential diagnosis that includes benign lesions such as focal inflammation, focal fibrosis, and organizing pneumonia.
Abstract: Pulmonary nodule characterization is currently being redefined as new clinical, radiologic, and pathologic data are reported, necessitating a reevaluation of the clinical management, especially of subsolid nodules. These are now known to frequently, although not invariably, fall into the spectrum of peripheral adenocarcinomas of the lung. Strong correlation between the Noguchi histologic classification and computed tomographic (CT) appearances of these lesions, in particular, has been reported. Serial CT findings have further documented that stepwise progression of lesions with ground-glass opacity, manifested as an increase in size or the appearance and/or subsequent increase of solid components, does occur in a select subset of patients. As a consequence, recognition of the potential association between subsolid nodules and peripheral adenocarcinomas requires a review of current guidelines for the management of these lesions, further necessitated by a differential diagnosis that includes benign lesions such as focal inflammation, focal fibrosis, and organizing pneumonia. Specific issues that need to be addressed are the need for consensus regarding an appropriate CT classification, methods for precise measurement of subsolid nodules, including the extent of both ground-glass and solid components, as well as accurate assessment of the growth rates as means for predicting malignancy and prognosis. It is anticipated that interim guidelines may serve to standardize our current management of these lesions, pending further clarification of their natural history.
TL;DR: Substantial decreases in the growth of outpatient CT and US procedure volume coincident with ROE implementation (supplemented by DS for CT) were observed and the utilization of outpatient MR imaging decreased less impressively.
Abstract: Purpose: To determine the effect of a computerized radiology order entry (ROE) and decision support (DS) system on growth rate of outpatient computed tomography (CT), magnetic resonance (MR) imaging, and ultrasonography (US) procedure volumes over time at a large metropolitan academic medical center. Materials and Methods: Institutional review board approval was obtained for this study of deidentified aggregate administrative data. The research was compliant with HIPAA; informed consent was waived. This was a retrospective study of outpatient advanced imaging utilization before, during, and after implementation of a Web-based ROE and DS system. Dependent variables were the quarterly volumes of outpatient CT, MR imaging, and US examinations from quarter 4 of 2000 through quarter 4 of 2007. Outpatient visits during each quarter were included as control variables. These data were analyzed as three separate time series with piecewise linear regression for simultaneous estimation of quarterly examination volume trends before and after ROE and DS system implementation. This procedure was repeated with log-transformed quarterly volumes to estimate percentage growth rates.
TL;DR: Clear cell, papillary, and chromophobe RCCs demonstrate different patterns of enhancement on two-time point clinical dynamic contrast agent-enhanced magnetic resonance (MR) images, allowing their differentiation with high sensitivity and specificity.
Abstract: Purpose: To retrospectively evaluate whether the enhancement patterns of pathologically proved clear cell, papillary, and chromophobe renal cell carcinomas (RCCs) measured on clinical dynamic contrast agent–enhanced magnetic resonance (MR) images permit accurate diagnosis of RCC subtype. Materials and Methods: This study was Institutional Review Board approved and HIPAA compliant; informed consent was waived. One hundred twelve patients (76 men, 36 women; age range, 25–88 years; mean age, 58.1 years) underwent MR imaging of 113 renal masses (mean diameter, 5.4 cm) with pathologic diagnoses of clear cell (n = 75), papillary (n = 28), or chromophobe (n = 10) RCC. A 1.5-T clinical MR protocol was used before and after (corticomedullary and nephrographic phases) intravenous administration of contrast agent. Region-of-interest measurements within tumor and uninvolved renal cortex were used to calculate percentage signal intensity change and tumor-to-cortex enhancement index. Subtype groups were compared by usi...
TL;DR: Optimum ADC determination and DW imaging quality at 3.0 T was found with a combined b value protocol of 50 and 850 sec/mm(2), which provided a high accuracy for differentiation of benign and malignant breast tumors.
Abstract: Standardization of b values allows improved interstudy comparisons on the diagnostic accuracy of diffusion-weighted MR breast examinations.
TL;DR: R2* measurements can be used to quantify brain iron accumulation and thus may allow better evaluation of neurodegenerative diseases associated with iron deposition, as well as compare with previously reported iron concentrations found in autopsy material.
Abstract: Purpose: To determine the values of iron accumulation in the basal ganglia of healthy volunteers of different ages with R2* and raw signal intensity measurements from T1-weighted magnetic resonance (MR) images, supported by voxel-based relaxometry (VBR), and to compare them with previously reported iron concentrations found in autopsy material. Materials and Methods: The ethics committee approved the study, and the participants or their parents gave written informed consent. Eighty subjects (41 female and 39 male subjects; age range, 1–80 years) were examined at 1.5 T. For each subject, R2* values were calculated. Curves for R2* versus age were obtained for globus pallidus (GP), putamen, caudate nucleus, substantia nigra (SN), and frontal white matter (FWM). To highlight possible differences in iron concentration among the age decades, VBR was applied. Signal intensity values were estimated on T1-weighted fast low-angle shot images, and regions of interest were drawn in each nucleus. R2* values were also ...
TL;DR: Using clinical history, lesion location, mineralization on radiographs, and signal intensity characteristics on magnetic resonance images, one can determine the diagnosis for the subset of determinate lesions that have characteristic clinical and imaging features and narrow the differential diagnosis for lesions that demonstrate indeterminate characteristics.
Abstract: Soft-tissue lesions are frequently encountered by radiologists in everyday clinical practice. Characterization of these soft-tissue lesions remains problematic, despite advances in imaging. By systematically using clinical history, lesion location, mineralization on radiographs, and signal intensity characteristics on magnetic resonance images, one can (a) determine the diagnosis for the subset of determinate lesions that have characteristic clinical and imaging features and (b) narrow the differential diagnosis for lesions that demonstrate indeterminate characteristics. If a lesion cannot be characterized as a benign entity, the lesion should be reported as indeterminate, and the patient should undergo biopsy to exclude malignancy.