Showing papers in "Radiology in 2005"
TL;DR: The authors believe that the time-honored requirement to follow every small indeterminate nodule with serial CT should be revised and new guidelines are proposed for follow-up and management of small pulmonary nodules detected on CT scans.
Abstract: Lung nodules are detected very commonly on computed tomographic (CT) scans of the chest, and the ability to detect very small nodules improves with each new generation of CT scanner. In reported studies, up to 51% of smokers aged 50 years or older have pulmonary nodules on CT scans. However, the existing guidelines for follow-up and management of noncalcified nodules detected on nonscreening CT scans were developed before widespread use of multi–detector row CT and still indicate that every indeterminate nodule should be followed with serial CT for a minimum of 2 years. This policy, which requires large numbers of studies to be performed at considerable expense and with substantial radiation exposure for the affected population, has not proved to be beneficial or cost-effective. During the past 5 years, new information regarding prevalence, biologic characteristics, and growth rates of small lung cancers has become available; thus, the authors believe that the time-honored requirement to follow every smal...
1,434 citations
TL;DR: It is the group's intention that adherence to the recommendations will facilitate achievement of the main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes.
Abstract: The field of interventional oncology with use of image-guided tumor ablation requires standardization of terminology and reporting criteria to facilitate effective communication of ideas and appropriate comparison between treatments that use different technologies, such as chemical (ethanol or acetic acid) ablation, and thermal therapies, such as radiofrequency, laser, microwave, ultrasound, and cryoablation. This document provides a framework that will hopefully facilitate the clearest communication between investigators and will provide the greatest flexibility in comparison between the many new, exciting, and emerging technologies. An appropriate vehicle for reporting the various aspects of image-guided ablation therapy, including classification of therapies and procedure terms, appropriate descriptors of imaging guidance, and terminology to define imaging and pathologic findings, are outlined. Methods for standardizing the reporting of follow-up findings and complications and other important aspects that require attention when reporting clinical results are addressed. It is the group's intention that adherence to the recommendations will facilitate achievement of the group's main objective: improved precision and communication in this field that lead to more accurate comparison of technologies and results and, ultimately, to improved patient outcomes.
1,266 citations
Harvard University1, Mayo Clinic2, University of California, San Francisco3, University of Pennsylvania4, Brown University5, University of Texas Health Science Center at Houston6, Duke University7, Thomas Jefferson University8, Stanford University9, Washington University in St. Louis10, University of Texas MD Anderson Cancer Center11, University of Alabama at Birmingham12
TL;DR: The recommendations in this consensus statement, which are based on analysis of the current literature and common practice strategies, are thought to represent a reasonable approach to thyroid nodular disease.
Abstract: The Society of Radiologists in Ultrasound convened a panel of specialists from a variety of medical disciplines to come to a consensus on the management of thyroid nodules identified with thyroid ultrasonography (US), with particular focus on which nodules should be subjected to US-guided fine needle aspiration and which thyroid nodules need not be subjected to fine-needle aspiration. The panel met in Washington, DC, October 26–27, 2004, and created this consensus statement. The recommendations in this consensus statement, which are based on analysis of the current literature and common practice strategies, are thought to represent a reasonable approach to thyroid nodular disease. © RSNA, 2005
1,093 citations
TL;DR: RF ablation is an effective first-line treatment for cirrhotic patients with early-stage HCC who were excluded from surgery and who had Child class A or B cirrhosis with either a single HCC less than or equal to 5 cm in diameter or multiple (as many as three) HCCs less than and equal to 3cm in diameter each.
Abstract: PURPOSE: To perform a prospective, intention-to-treat clinical trial to determine the long-term survival rates of patients with hepatic cirrhosis and early-stage hepatocellular carcinoma (HCC) in whom percutaneous image-guided radiofrequency (RF) ablation was used as the sole first-line anticancer treatment. MATERIALS AND METHODS: The study was performed with approval of the ethics committee, and written informed consent was obtained for all patients. From June 1, 1996, to January 1, 2003, 206 patients (143 men, 63 women; age range, 51–81 years; mean age, 67 years ± 7) who were excluded from surgery and who had Child class A or B cirrhosis with either a single HCC less than or equal to 5 cm in diameter or multiple (as many as three) HCCs less than or equal to 3 cm in diameter each were enrolled. RF ablation was performed in 187 (91%) of 206 patients; 19 (9%) were excluded from RF treatment because of unfavorable tumor location. Follow-up ranged from 3 to 78 months (mean, 24 months ± 21) and included measu...
793 citations
TL;DR: If predictive value of calcified coronary artery plaque for cardiovascular events proves sufficient to justify screening a segment of the population, then a standardized cardiac CT protocol is feasible and will provide reproducible results for health care providers and the public.
Abstract: Calcified coronary artery plaque, measured at cardiac computed tomography (CT), is a predictor of cardiovascular disease and may play an increasing role in cardiovascular disease risk assessment. The Multi-Ethnic Study of Atherosclerosis (MESA) and the Coronary Artery Risk Development in Young Adults (CARDIA) study of the National Heart, Lung, and Blood Institute are population-based studies in which calcified coronary artery plaque was measured with electron-beam and multi–detector row CT and a standardized protocol in 6814 (MESA) and 3044 (CARDIA study) participants. The studies were approved by the appropriate institutional review board from the study site or agency, and written informed consent was obtained from each participant. Participation in the CT examination was high, image quality was good, and agreement for the presence of calcified plaque was high (κ = 0.92, MESA; κ = 0.77, CARDIA study). Extremely high agreement was observed between and within CT image analysts for the presence (κ > 0.90, a...
779 citations
TL;DR: Elastography is a promising imaging technique that can assist in the differential diagnosis of thyroid gland cancer, and the usefulness of these criteria was not considered to be high because of their low sensitivity.
Abstract: PURPOSE: To prospectively evaluate the elastographic appearance of thyroid gland tumors and explore the potential sensitivity and specificity of ultrasonographic (US) elastography for differentiating benign and malignant tumors, with histopathologic analysis as the reference standard. MATERIALS AND METHODS: The study was institutional review board approved, and each patient gave written informed consent. Fifty-two thyroid gland lesions (22 malignant, 30 benign) in 31 consecutive patients (six men, 25 women; mean age, 49.7 years ± 14.7 [standard deviation]) were examined with real-time elastography in the elasticity imaging mode implemented on a clinical US scanner modified for research. In addition, the radiofrequency echo data stored during US were exported from the scanner and used for off-line strain image reconstruction. All elastograms were evaluated for the lesion visibility, relative brightness, and margin regularity and definition by using a four-point scale. In addition, normal thyroid gland tiss...
621 citations
TL;DR: CT allows detection of early-stage lung cancers andBenign nodule detection rate is high, and results suggest no stage shift.
Abstract: PURPOSE: To report results of a 5-year prospective low-dose helical chest computed tomographic (CT) study of a cohort at high risk for lung cancer. MATERIALS AND METHODS: After informed written consent was obtained, 1520 individuals were enrolled. Protocol was approved by institutional review board and National Cancer Institute and was compliant with Health Insurance Portability and Accountability Act, or HIPAA. Participants were aged 50 years and older and had smoked for more than 20 pack-years. Participants underwent five annual (one initial and four subsequent) CT examinations. A significant downward shift was evaluated in non–small cell lung cancers detected initially from advanced stage down to stage I by using a one-sided binomial test of proportions. Poisson regression and Fisher exact tests were used for comparisons with Mayo Lung Project. RESULTS: In 788 (52%) men and 732 (48%) women, 61% (927 of 1520) were current smokers, and 39% were former smokers. After five annual CT examinations, 3356 unca...
597 citations
TL;DR: A practical guide to the interpretation of CT colonography results: the CT Colonography Reporting and Data System, or “C-RADS,” is presented, which is coupled to recommendations for follow-up.
Abstract: Computed tomographic (CT) colonography continues to evolve rapidly. Advances in scanning and display technologies, encouraging performance data, and increased utilization necessitate clarification and standardization of results reporting in CT colonography. There are several reasons for this. First and most important, standardized reporting can better assist patients and referring physicians in making management decisions on the basis of the results of CT colonography. The precedent of the mammography Breast Imaging Reporting and Data System, or BI-RADS, schema is a strong incentive to provide a similar structure for CT colonography. Second, as more examinations are performed, the likelihood increases that radiologists interpreting results of a CT colonography examination performed at one center will require comparison to examination results and reports generated at other sites. As has been seen with mammography, a common set of terms facilitates this kind of assessment (1). Third, as utilization of CT colonography increases, our colleagues in other medical specialties, the various third-party payers, and the general public will insist on larger-scale evaluations of examination performance, examination quality, patient outcome, and cost. Here again, a common approach to interpretation will assist us in meeting these demands. Finally, a common scheme for reporting facilitates structured reporting. The purpose of this communication is to facilitate clear and consistent communication of CT colonography results. The authors—an ad hoc group of investigators active in the area of CT colonography—have collaborated to develop a reporting scheme that is coupled to recommendations for follow-up. Our group, the Working Group on Virtual Colonoscopy, includes members of the American College of Radiology Colon Cancer Committee. On the basis of our collective experience and a review of the relevant literature, we present a practical guide to the interpretation of CT colonography results: the CT Colonography Reporting and Data System, or “C-RADS.” Future multidisciplinary collaboration and longitudinal data may lead to a refinement of the terms and concepts we present here; our effort is a starting point in which we attempt to address the needs of current practice. Adequate training and rigorous quality control of examination performance are essential elements for maximizing the potential of CT colonography; however, these related topics will not be discussed here. Instead, we will focus on the interpretation and follow-up of CT colonography results in three parts: first, a description of terms useful for reporting the size, morphologic features, and location of polyps and masses; second, a description of a classification scheme for colonic lesions and suggestions for follow-up; Published online 10.1148/radiol.2361041926 Radiology 2005; 236:3–9 1 From the Division of Abdominal Imaging and Intervention, Department of Radiology/ White 270, Massachusetts General Hospital, Boston, MA 02114 (M.E.Z.). The complete list of author affiliations is at the end of this article. Received November 12, 2004; accepted November 15. Address correspondence to M.E.Z. (e-mail: mzalis@partners.org).
595 citations
TL;DR: Arterial spin-labeling MR imaging showed regional hypoperfusion with AD, in brain regions similar to those seen in FDG PET and HMPAO SPECT studies of similar populations; this hypoperFusion persists after accounting for underlying cortical gray matter atrophy.
Abstract: PURPOSE: To prospectively determine if pulsed arterial spin-labeling perfusion magnetic resonance (MR) imaging depicts regional cerebral hypoperfusion in subjects with Alzheimer disease (AD) and mild cognitive impairment (MCI), compared with perfusion in cognitively normal (CN) subjects, that is consistent with results of fluorodeoxyglucose (FDG) positron emission tomography (PET) and hexamethylpropyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) studies of similar populations. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Twenty subjects with AD (13 men, seven women; mean age, 72.9 years), 18 with MCI (nine men, nine women; mean age, 73.3 years), and 23 CN subjects (10 men, 13 women; mean age, 72.9 years) underwent arterial spin-labeling and volumetric T1-weighted structural MR imaging. Perfusion images were coregistered to structural images, corrected for partial volume effects (PVEs) with information from the structural image t...
563 citations
TL;DR: FDG PET had significantly higher sensitivity on a per-patient basis, compared with that of the other modalities, but not on aper-lesion basis.
Abstract: PURPOSE: To perform a meta-analysis to obtain sensitivity estimates of computed tomography (CT), magnetic resonance (MR) imaging, and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) for detection of colorectal liver metastases on per-patient and per-lesion bases. MATERIALS AND METHODS: MEDLINE, EMBASE, Web of Science, and CANCERLIT databases and Cochrane Database of Systematic Reviews were searched for relevant original articles published from January 1990 to December 2003. Criteria for inclusion of articles were as follows: Articles were reported in the English, German, or French language; CT, MR imaging, or FDG PET was performed to identify and characterize colorectal liver metastases; histopathologic analysis (surgery, biopsy, or autopsy), intraoperative observation (manual palpatation, intraoperative ultrasonography [US]), and/or follow-up US was the reference standard; and data were sufficient for calculation of true-positive or false-negative values. A random-effects linear r...
529 citations
TL;DR: In this paper, the depiction of intracortical lesions by using multislab three-dimensional (3D) double inversion-recovery (DIR), multiislab 3D fluid-attenuated inversion recovery (FLAIR), and T2-weighted spin-echo (SE) imaging in patients with multiple sclerosis was compared.
Abstract: PURPOSE: To prospectively compare the depiction of intracortical lesions by using multislab three-dimensional (3D) double inversion-recovery (DIR), multislab 3D fluid-attenuated inversion-recovery (FLAIR), and T2-weighted spin-echo (SE) magnetic resonance (MR) imaging in patients with multiple sclerosis. MATERIALS AND METHODS: Local ethics review board approval and informed consent were obtained. Conventional T2-weighted SE and multislab 3D FLAIR and DIR images were acquired in 10 patients with multiple sclerosis (five women, five men) and 11 age-matched healthy control subjects (seven women, four men). Mean age was 40 years (range, 25–54 years) in patients and 34 years (range, 24–55 years) in control subjects. Lesions were classified according to seven anatomic regions: intracortical, mixed white matter–gray matter, juxtacortical, deep gray matter, periventricular white matter, deep white matter, and infratentorial lesions. The numbers of lesions per category were compared between techniques (Dunnett-cor...
TL;DR: Markers of RVD and pulmonary vascular obstruction, assessed with helical CT at baseline, help predict mortality during follow-up.
Abstract: PURPOSE: To retrospectively quantify right ventricular dysfunction (RVD) and the pulmonary artery obstruction index at helical computed tomography (CT) on the basis of various criteria proposed in the literature and to assess the predictive value of these CT parameters for mortality within 3 months after the initial diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was not required for retrospective study. In 120 consecutive patients (55 men, 65 women; mean age ± standard deviation, 59 years ± 18) with proved PE, two readers assessed the extent of RVD by quantifying the ratio of the right ventricle to left ventricle short-axis diameters (RV/LV) and the pulmonary artery to ascending aorta diameters, the shape of the interventricular septum, and the extent of obstruction to the pulmonary artery circulation on helical CT images, which were blinded for clinical outcome in consensus reading. Regression analysis was used to correl...
TL;DR: ADC is useful for differentiation of some human brain tumors, particularly DNT, malignant lymphomas versus glioblastomas and metastatic tumors, and ependymomas versus PNETs.
Abstract: PURPOSE: To determine if apparent diffusion coefficient (ADC) can be used to differentiate brain tumors at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Institutional review board approval or informed patient consent was not required. MR images were reviewed retrospectively in 275 patients with brain tumors: 147 males and 128 females 1–81 years old, treated between September 1997 and July 2003. Regions of interest were placed manually in tumor regions on MR images, and ADC was calculated with a five-point regression method at b values of 0, 250, 500, 750, and 1000 sec/mm2. ADC values were average values in tumor. All brain tumor subgroups were analyzed. Logistic discriminant analysis was performed by using ADC, age, and patient sex as independent variables to discriminate among tumor groups. RESULTS: A significant negative correlation existed between ADC and astrocytic tumors of World Health Organization grades 2–4 (grade 2 vs grades 3 and 4, accuracy of 91.3% [P < .01]; grade 3 vs 4, accuracy o...
TL;DR: MW ablation may be less affected by the heat-sink effect that is thought to contribute to local recurrence after RF ablation, and radiofrequency ablation zones are similar in pathologic appearance and imaging characteristics.
Abstract: PURPOSE: To compare microwave (MW) and radiofrequency (RF) ablation in a hepatic porcine model. MATERIALS AND METHODS: Institutional animal research committee approval was obtained. Nineteen pigs were divided into groups based on time of sacrifice (group A, immediate; group B, 2 days; group C, 28 days; group D, 28 days). Groups A, B, and C each underwent a combination of RF and MW ablation. Group D underwent either four MW or four RF ablations. Ablation was performed with a prototype MW device (915 Mhz, 40 W, 10 minutes) and a commercial RF system (150 W, 10 minutes, 3-cm deployment). Computed tomography (CT) was performed in groups B and C at 2 days and in group C at 28 days. Group D underwent serial laboratory testing. Specimens were serially sectioned, and short-axis diameter and length of each were measured. The percentage deflection caused by local blood vessels (heat-sink effect) was also measured in group A. Likelihood ratio tests and unpaired t tests were used for statistical analyses as appropria...
TL;DR: Integrated FDG PET/CT is significantly better than stand-alone CT for lung cancer staging and provides enhanced accuracy and specificity in nodal staging.
Abstract: PURPOSE: To evaluate prospectively the accuracy of integrated positron emission tomography (PET) and computed tomography (CT) with use of fluorodeoxyglucose (FDG), compared with that of stand-alone CT, for the preoperative staging of non–small cell lung cancer, with surgical and histologic findings used as the reference standard. MATERIALS AND METHODS: Institutional review board approval and patient informed consent were obtained. From November 2003 to February 2004, 106 patients (78 men, 28 women; mean age, 56 years) with non–small cell lung cancer underwent curative surgical resection (tumor resection and lymph node dissection) after stand-alone CT followed by integrated FDG PET/CT. Tumor stages were determined by using the TNM and American Joint Committee on Cancer staging systems. Histopathologic results served as the reference standard. Statistically significant differences in tumor staging between integrated PET/CT and stand-alone CT were determined with P < .05 obtained by using the McNemar test or...
TL;DR: The authors present their technique in the performance of CT and MR imaging examinations, summarize their approach to the diagnosis of renal masses, review the imaging findings in these lesions, and stress the limitations in renal mass diagnosis.
Abstract: With modern computed tomography (CT) and magnetic resonance (MR) imaging equipment, the diagnosis of most renal masses is usually straightforward and accurate. The major question to be answered is whether the mass represents a surgical or nonsurgical lesion or, in some cases, if follow-up studies are necessary. This evaluation usually can be accomplished if a high-quality examination is performed, if the clinical history of the patient is kept in mind, if conditions that mimic a renal neoplasm are considered and excluded, and if there is an awareness of the potential pitfalls and limitations of CT and MR imaging. In this article, the authors present their technique in the performance of CT and MR imaging examinations, summarize their approach to the diagnosis of renal masses, review the imaging findings in these lesions, and stress the limitations in renal mass diagnosis.
TL;DR: By decreasing the tube voltage, the amount of contrast material can be reduced without image quality degradation, and higher contrast material enhancement can be achieved in scans obtained with a low tube voltage.
Abstract: PURPOSE: To prospectively investigate the effect of low tube voltage on radiation dose, contrast enhancement, image quality, and image noise at abdominal dynamic computed tomography (CT). MATERIALS AND METHODS: The institutional review board approved this study. Prior informed consent was obtained from all patients. Forty patients (24 women, 16 men; mean age, 62 years) underwent initial abdominal CT at 120 kV with 100 mL of contrast material (protocol A). Then all patients were randomly assigned to one of two protocols (protocol B, CT at 90 kV with 100 mL contrast material; protocol C, CT at 90 kV with 80 mL contrast material). The CT numbers of their abdominal organs were assessed quantitatively and qualitatively. Statistical analysis was performed by using the two-tailed paired t test, Kruskal-Wallis test, and κ test of interobserver agreement. The radiation dose was measured with a phantom that consisted of glass-rod dosimeters. RESULTS: Quantitative analysis revealed that protocols B and C yielded sig...
TL;DR: CT colonography seems sufficiently sensitive and specific in the detection of large and medium polyps; it is especially sensitive in the Detection of symptomatic cancer.
Abstract: PURPOSE: To assess the methodologic quality of available data in published reports of computed tomographic (CT) colonography by performing systematic review and meta-analysis.MATERIALS AND METHODS: The MEDLINE database was searched for colonography reports published between 1994 and 2003, without language restriction. The terms colonography, colography, CT colonoscopy, CT pneumocolon, virtual colonoscopy, and virtual endoscopy were used. Studies were selected if the focus was detection of colorectal polyps verified with within-subject reference colonoscopy by using key methodologic criteria based on information presented at the Fourth International Symposium on Virtual Colonoscopy (Boston, Mass). Two reviewers independently abstracted methodologic characteristics. Per-patient and per-polyp detection rates were extracted, and authors were contacted, when necessary. Per-patient sensitivity and specificity were calculated for different lesion size categories, and Forest plots were produced. Meta-analysis of paired sensitivity and specificity was conducted by using a hierarchical model that enabled estimation of summary receiver operating characteristic curves allowing for variation in diagnostic threshold, and the average operating point was calculated. Per-polyp sensitivity was also calculated.RESULTS: Of 1398 studies considered for inclusion, 24 met our criteria. There were 4181 patients with a study prevalence of abnormality of 15%-72%. Meta-analysis of 2610 patients, 206 of whom had large polyps, showed high per-patient average sensitivity (93%; 95% confidence interval [CI]: 73%, 98%) and specificity (97%; 95% CI: 95%, 99%) for colonography; sensitivity and specificity decreased to 86% (95% CI: 75%, 93%) and 86% (95% CI: 76%, 93%), respectively, when the threshold was lowered to include medium polyps. When polyps of all sizes were included, studies were too heterogeneous in sensitivity (range, 45%-97%) and specificity (range, 26%-97%) to allow meaningful meta-analysis. Of 150 cancers, 144 were detected (sensitivity, 95.9%; 95% CI: 91.4%, 98.5%). Data reporting was frequently incomplete, with no generally accepted format.CONCLUSION: CT colonography seems sufficiently sensitive and specific in the detection of large and medium polyps; it is especially sensitive in the detection of symptomatic cancer. Studies are poorly reported, however, and the authors propose a minimum data set for study reporting. (c) RSNA, 2005.
TL;DR: MR spectroscopic imaging measurement of prostate tumor (Cho + Cr)/Cit and tumor volume correlate with pathologic Gleason score and has potential in noninvasive assessment of prostate cancer aggressiveness.
Abstract: PURPOSE: To determine whether hydrogen 1 magnetic resonance (MR) spectroscopic imaging can be used to predict aggressiveness of prostate cancer. MATERIALS AND METHODS: All patients gave informed consent according to an institutionally approved research protocol. A total of 123 patients (median age, 58 years; age range, 40–74 years) who underwent endorectal MR imaging and MR spectroscopic imaging between January 2000 and December 2002 were included. MR imaging and spectroscopy were performed by using combined pelvic phased-array and endorectal probe. Water and lipids were suppressed, and phase-encoded data were acquired with 6.2-mm resolution. Voxels in the peripheral zone were considered suspicious for cancer if (Cho + Cr)/Cit was at least two standard deviations above the normal level, where Cho represents choline-containing compounds, Cr represents creatine and phosphocreatine, and Cit represents citrate. Correlation between metabolite ratio and four Gleason score groups identified at step-section patho...
TL;DR: Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia and subjects with normal bone density.
Abstract: PURPOSE: To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material–enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA). MATERIALS AND METHODS: This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67–101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes. RESULTS: Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73...
TL;DR: Liver-specific enhancement of focal lesions is hepatocyte selective and correlates with various histopathologic diagnoses regarding presence of certain hepatocytic functions.
Abstract: PURPOSE: To detect hepatocyte-selective enhancement of focal lesions with gadoxetic acid at magnetic resonance (MR) imaging and to correlate enhancement in hepatocyte-selective phases with histopathologic findings and in arterial and portal venous phases with biphasic computed tomographic (CT) findings. MATERIALS AND METHODS: Study was supported by local ethics committee; all patients gave written informed consent. In 19 men and 14 women recruited in three clinical studies, histopathologic correlation and CT scans of 41 focal lesions (13 primary malignant lesions, 21 metastases, three adenomas, three cases of focal nodular hyperplasia [FNH], and one cystadenoma) and ultrasonographic confirmation of five cysts were available. MR was performed before and during arterial and portal venous phases and in hepatocyte-selective phases 10 and 20 minutes after injection of gadoxetic acid. Enhancement was evaluated in consensus by two observers. Enhancement pattern and morphologic features during arterial and portal...
TL;DR: DW MR imaging is feasible and reproducible in the assessment of renal function, as shown in the initial experience with a small number of patients and volunteers.
Abstract: PURPOSE: To prospectively evaluate feasibility of diffusion-weighted (DW) magnetic resonance (MR) imaging in assessment of renal function in healthy volunteers and patients with various renal abnormalities and to prospectively evaluate reproducibility of DW MR imaging in volunteers. MATERIALS AND METHODS: Study protocol was approved by local ethics committee; informed consent was obtained. Eighteen healthy volunteers and 15 patients underwent transverse fat-saturated echo-planar DW MR imaging of the kidneys during normal breathing. Freehand regions of interest were delineated in the cortex and medulla of the kidneys. The following apparent diffusion coefficient (ADC) values were calculated: ADC of all b values (ADCavg), ADC of low b values (b = 0, 50, 100 sec/mm2; ADClow), and ADC of high b values (b = 500, 750, 1000 sec/mm2; ADChigh). These values were calculated to differentiate influence of perfusion and diffusion. Reproducibility was assessed by repeating the same protocol in five randomly selected vo...
TL;DR: The introduction in 1998 of multi-detector row computed tomography by the major CT vendors was a milestone with regard to increased scan speed, improved z-axis spatial resolution, and better utilization of the available x-ray power.
Abstract: The introduction in 1998 of multi-detector row computed tomography (CT) by the major CT vendors was a milestone with regard to increased scan speed, improved z-axis spatial resolution, and better utilization of the available x-ray power. In this review, the general technical principles of multi-detector row CT are reviewed as they apply to the established four- and eight-section systems, the most recent 16-section scanners, and future generations of multi-detector row CT systems. Clinical examples are used to demonstrate both the potential and the limitations of the different scanner types. When necessary, standard single-section CT is referred to as a common basis and starting point for further developments. Another focus is the increasingly important topic of patient radiation exposure, successful dose management, and strategies for dose reduction. Finally, the evolutionary steps from traditional single-section spiral image-reconstruction algorithms to the most recent approaches toward multisection spiral reconstruction are traced.
TL;DR: An automatic exposure control mechanism that is based on real-time anatomy-dependent tube current modulation delivers good image quality with a significantly reduced radiation dose.
Abstract: PURPOSE: To prospectively compare dose reduction and image quality achieved with an automatic exposure control system that is based on both angular (x-y axis) and z-axis tube current modulation with dose reduction and image quality achieved with an angular modulation system for multi–detector row computed tomography (CT). MATERIALS AND METHODS: The study protocol was approved by the institutional review board, and oral informed consent was obtained. In two groups of 200 patients, five anatomic regions (ie, the thorax, abdomen-pelvis, abdomen-liver, lumbar spine, and cervical spine) were examined with this modulation system and a six-section multi–detector row CT scanner. Data from these patients were compared with data from 200 patients who were examined with an angular modulation system. Dose reduction by means of reduction of the mean effective tube current in 600 examinations, image noise in 200 examinations performed with each modulation system, and subjective image quality scores in 100 examinations ...
TL;DR: Histologic evidence directly validates RF ablation as an effective treatment of small (<3 cm) HCC, according to the Fisher exact test.
Abstract: PURPOSE: To retrospectively evaluate the effectiveness of radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) by using histologic examination of the explanted liver. MATERIALS AND METHODS: The study was approved by the medical center Institutional Review Board, with waiver of informed consent. Forty-seven HCC nodules in 24 patients (18 men, six women; age range, 33–71 years; mean age, 56 years) were treated with single or double RF ablation sessions prior to liver transplantation. Histologic data from hematoxylin-eosin staining of explanted liver specimens were retrospectively reviewed to determine treatment success, which was defined as the absence of residual or recurrent viable carcinoma cells at treatment site. Tumor size and the presence of large (≥3 mm) abutting vessels that were observed during imaging were tested as potential predictors of treatment success or failure (Fisher exact test). In patients who underwent postablation computed tomographic (CT) or magnetic resonance (MR) imaging...
TL;DR: Accurate differentiation of FNH from HA and LA is achievable on delayed T1-weighted GRE images after administration of gadobenate dimeglumine, according to sensitivity, specificity, positive predictive value (PPV), negative predictivevalue (NPV, and overall accuracy)
Abstract: PURPOSE: To prospectively determine the accuracy of differentiating benign focal nodular hyperplasia (FNH) from hepatic adenoma (HA) and liver adenomatosis (LA) by using gadobenate dimeglumine–enhanced magnetic resonance (MR) imaging. MATERIALS AND METHODS: The ethics committee at each center approved the study, and all patients provided informed consent. Seventy-three patients with confirmed FNH and 35 patients with confirmed HA (n = 27) or LA (n = 8) underwent MR imaging before (T2-weighted half-Fourier rapid acquisition with relaxation enhancement or T2-weighted fast spin-echo and T1-weighted gradient-echo [GRE] sequences) and at 25–30 seconds (arterial phase), 70–90 seconds (portal venous phase), 3–5 minutes (equilibrium phase), and 1–3 hours (delayed phase) after (T1-weighted GRE sequences only, with or without fat suppression) bolus administration of 0.1 mmol per kilogram of body weight gadobenate dimeglumine. The enhancement of 235 lesions (128 FNH, 32 HA, and 75 LA lesions) relative to the normal ...
TL;DR: Idiopathic interstitial pneumonias comprise usual interstitial pneumonia (UIP), nonspecific interstitialneumonias (NSIP), desquamative interstitial lungs disease (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), cryptogenic organizing pneumonia (COP), acute interinterstitial pneumonia (AIP), and lymphoid interInterstitial pneumonia (LIP).
Abstract: Idiopathic interstitial pneumonias comprise usual interstitial pneumonia (UIP), nonspecific interstitial pneumonia (NSIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), cryptogenic organizing pneumonia (COP), acute interstitial pneumonia (AIP), and lymphoid interstitial pneumonia (LIP). Each of these entities has a typical imaging and histologic pattern, although in practice the imaging patterns may be variable. Each entity may be idiopathic or may be secondary to a recognizable cause such as collagen vascular disease or inhalational exposure. The diagnosis of idiopathic interstitial pneumonia is made by means of correlation of clinical, imaging, and pathologic features. The characteristic computed tomographic (CT) features of UIP are predominantly basal and peripheral reticular pattern with honeycombing and traction bronchiectasis. NSIP is characterized by predominantly basal ground-glass opacity and/or reticular pattern, often with traction bronchiectasis. DIP and RB-ILD are smoking-related lung diseases characterized by ground-glass opacity and centrilobular nodules. COP is characterized by patchy peripheral or peribronchovascular consolidation. AIP manifests as diffuse lung consolidation and ground-glass opacity. LIP is associated with a CT pattern of ground-glass opacity sometimes associated with perivascular cysts.
TL;DR: ROC analyses demonstrated that PET/CT is significantly superior to PET or CT alone for depiction of malignancy in the head and neck (P < .05), and radiologist confidence is improved with the combined modality.
Abstract: PURPOSE: To prospectively determine whether combined positron emission tomography (PET) and computed tomography (CT) is more accurate than either PET or CT alone in depicting malignant lesions in the head and neck. MATERIALS AND METHODS: Study was approved by the institutional review board, and patient informed consent was waived. Sixty-five consecutive patients (42 men, 23 women; age range, 43–83 years) known to have or suspected of having head and neck cancer were examined with combined PET/CT. CT was performed with intravenous administration of a contrast agent, and the CT data were used for attenuation correction. Each examination was interpreted in three ways: PET images in the absence of CT data, CT images in the absence of PET data, and fused PET/CT images. Probability of malignancy of each lesion was assigned a score by using a five-point scale. Receiver operating characteristic (ROC) analyses were performed by using biopsy, imaging, or clinical follow-up as the reference standard. The minimum fol...
TL;DR: Progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods.
Abstract: Improved therapeutic options for hepatocellular carcinoma and metastatic disease place greater demands on diagnostic and surveillance tests for liver disease. Existing diagnostic imaging techniques provide limited evaluation of tissue characteristics beyond morphology; perfusion imaging of the liver has potential to improve this shortcoming. The ability to resolve hepatic arterial and portal venous components of blood flow on a global and regional basis constitutes the primary goal of liver perfusion imaging. Earlier detection of primary and metastatic hepatic malignancies and cirrhosis may be possible on the basis of relative increases in hepatic arterial blood flow associated with these diseases. To date, liver flow scintigraphy and flow quantification at Doppler ultrasonography have focused on characterization of global abnormalities. Computed tomography (CT) and magnetic resonance (MR) imaging can provide regional and global parameters, a critical goal for tumor surveillance. Several challenges remain: reduced radiation doses associated with CT perfusion imaging, improved spatial and temporal resolution at MR imaging, accurate quantification of tissue contrast material at MR imaging, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods. Continued progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease.
TL;DR: MR arthrography demonstrated a triad of abnormal head-neck morphology, anterosuperior cartilage abnormality, and anterOSuperior labral abnormality in 37 of 42 patients with cam-type femoroacetabular impingement.
Abstract: PURPOSE: To retrospectively analyze magnetic resonance (MR) arthrographic findings in patients with clinical cam-type femoroacetabular impingement. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was waived. Study was compliant with the Health Insurance Portability and Accountability Act. Forty-two MR arthrograms obtained in 40 patients with clinical femoroacetabular impingement were analyzed retrospectively by two radiologists. Quantitative analysis by using α angle measurement was performed to assess anterosuperior femoral head-neck morphology. Presence of labral tears, articular cartilage lesions, paralabral cysts, os acetabuli, and synovial herniation pits was recorded. Presence of the typical triad of anterosuperior labral tear, anterosuperior cartilage lesion, and abnormal α angle was recorded. Surgical comparison was available for 11 patients. RESULTS: At imaging, in 40 patients (22 male, 18 female) with a mean age of 36.5 years, 39 of 42 hips ...