Showing papers in "Radiology in 2001"
TL;DR: The segmented inversion-recovery turboFLASH sequence produced the greatest differences in regional myocardial signal intensity in animals and patients and substantially improved differentiation between injured and normal regions.
Abstract: PURPOSE: To design a segmented inversion-recovery turbo fast low-angle shot (turboFLASH) magnetic resonance (MR) imaging pulse sequence for the visualization of myocardial infarction, compare this technique with other MR imaging approaches in a canine model of ischemic injury, and evaluate its utility in patients with coronary artery disease. MATERIALS AND METHODS: Six dogs and 18 patients were examined. In dogs, infarction was produced and images were acquired by using 10 different pulse sequences. In patients, the segmented turboFLASH technique was used to acquire contrast material–enhanced images 19 days ± 7 (SD) after myocardial infarction. RESULTS: Myocardial regions of increased signal intensity were observed in all animals and patients at imaging. With the postcontrast segmented turboFLASH sequence, the signal intensity of the infarcted myocardium was 1,080% ± 214 higher than that of the normal myocardium in dogs—nearly twice that of the next best sequence tested and approximately 10-fold greater t...
1,343 citations
TL;DR: The blood-brain barrier can be consistently opened with focused ultrasound exposures in the presence of a US contrast agent and MR imaging signal intensity changes may be useful in the detection of blood- brain barrier opening during sonication.
Abstract: PURPOSE: To determine if focused ultrasound beams can be used to locally open the blood-brain barrier without damage to surrounding brain tissue and if magnetic resonance (MR) imaging can be used to monitor this procedure. MATERIALS AND METHODS: The brains of 18 rabbits were sonicated (pulsed sonication) in four to six locations, with temporal peak acoustic power ranging from 0.2 to 11.5 W. Prior to each sonication, a bolus of ultrasonographic (US) contrast agent was injected into the ear vein of the rabbit. A series of fast or spoiled gradient-echo MR images were obtained during the sonications to monitor the temperature elevation and potential tissue changes. Contrast material–enhanced MR images obtained minutes after sonications and repeated 1–48 hours later were used to depict blood-brain barrier opening. Whole brain histologic evaluation was performed. RESULTS: Opening of the blood-brain barrier was confirmed with detection of MR imaging contrast agent at the targeted locations. The lowest power leve...
1,188 citations
TL;DR: RF ablation is an effective method to treat hepatic metastases from colorectal carcinoma and Frequency and time to local recurrence were related to lesion size (P < or =.001).
Abstract: PURPOSE: To describe the results of an ongoing radio-frequency (RF) ablation study in patients with hepatic metastases from colorectal carcinoma. MATERIALS AND METHODS: In 117 patients, 179 metachronous colorectal carcinoma hepatic metastases (0.9–9.6 cm in diameter) were treated with RF ablation by using 17-gauge internally cooled electrodes. Computed tomographic follow-up was performed every 4–6 months. Recurrent tumors were retreated when feasible. Time to new metastases and death for each patient and time to local recurrence for individual lesions were modeled with Kaplan-Meier analysis. Modeling determined the effect of number of metastases on the time to new metastases and death and effect of tumor size on local recurrence. RESULTS: Estimated median survival was 36 months (95% CI; 28, 52 months). Estimated 1, 2, and 3-year survival rates were 93%, 69%, and 46%, respectively. Survival was not significantly related to number of metastases treated. In 77 (66%) of 117 patients, new metastases were obser...
1,038 citations
TL;DR: The use of CAD in the interpretation of screening mammograms can increase the detection of early-stage malignancies without undue effect on the recall rate or positive predictive value for biopsy.
Abstract: PURPOSE: To prospectively assess the effect of computer-aided detection (CAD) on the interpretation of screening mammograms in a community breast center. MATERIALS AND METHODS: Over a 12-month period, 12,860 screening mammograms were interpreted with the assistance of a CAD system. Each mammogram was initially interpreted without the assistance of CAD, followed immediately by a reevaluation of areas marked by the CAD system. Data were recorded to measure the effect of CAD on the recall rate, positive predictive value for biopsy, cancer detection rate, and stage of malignancies at detection. RESULTS: When comparing the radiologist’s performance without CAD with that when CAD was used, the authors observed the following: (a) an increase in recall rate from 6.5% to 7.7%, (b) no change in the positive predictive value for biopsy at 38%, (c) a 19.5% increase in the number of cancers detected, and (d) an increase in the proportion of early-stage (0 and I) malignancies detected from 73% to 78%. CONCLUSION: The u...
801 citations
TL;DR: Technical requirements, potential clinical applications, and potential pitfalls and limitations of contrast-enhanced MR imaging as a method to help detect, diagnose, and stage breast cancer will be described.
Abstract: With the introduction of contrast agents, advances in surface coil technology, and development of new imaging protocols, contrast agent-enhanced magnetic resonance (MR) imaging has emerged as a promising modality for detection, diagnosis, and staging of breast cancer. The reported sensitivity of MR imaging for the visualization of invasive cancer has approached 100%. There are many examples in the literature of MR imaging--demonstrated mammographically, sonographically, and clinically occult breast cancer. Often, breast cancer detected on MR images has resulted in a change in patient care. Despite these results, there are many unresolved issues, including no defined standard technique for contrast-enhanced breast MR imaging, no standard interpretation criteria for evaluating such studies, no consensus on what constitutes clinically important enhancement, and no clearly defined clinical indications for the use of MR imaging. Furthermore, this technology remains costly, and issues of cost-effectiveness and cost competition from percutaneous biopsy have yet to be fully addressed. These factors along with the lack of commercially available MR imaging--guided localization and biopsy systems have slowed the transfer of this imaging technology from research centers to clinical breast imaging practices. Technical requirements, potential clinical applications, and potential pitfalls and limitations of contrast-enhanced MR imaging as a method to help detect, diagnose, and stage breast cancer will be described.
750 citations
TL;DR: MR imaging-guided FUS can be performed to noninvasively coagulate benign breast fibroadenomas and improve thermal imaging sequences over the treatment period, with 82% (279 of 342) of the hot spots visible in the last seven treatments.
Abstract: PURPOSE: To test the feasibility of noninvasive magnetic resonance (MR) imaging–guided focused ultrasound surgery (FUS) of benign fibroadenomas in the breast. MATERIALS AND METHODS: Eleven fibroadenomas in nine patients under local anesthesia were treated with MR imaging-guided FUS. Based on a T2-weighted definition of target volumes, sequential sonications were delivered to treat the entire target. Temperature-sensitive phase-difference–based MR imaging was performed during each sonication to monitor focus localization and tissue temperature changes. After the procedure, T2-weighted and contrast material–enhanced T1-weighted MR imaging were performed to evaluate immediate and long-term effects. RESULTS: Thermal imaging sequences were improved over the treatment period, with 82% (279 of 342) of the hot spots visible in the last seven treatments. The MR imager was used to measure temperature elevation (12.8°–49.9°C) from these treatments. Eight of the 11 lesions treated demonstrated complete or partial lac...
632 citations
TL;DR: Measurement of ADCs may be used to characterize head and neck lesions and the highest accuracy of 86%, with 84% sensitivity and 91% specificity, was obtained.
Abstract: PURPOSE: To evaluate whether apparent diffusion coefficients (ADCs) calculated from diffusion-weighted echo-planar magnetic resonance (MR) images can be used to characterize head and neck lesions MATERIALS AND METHODS: Diffusion-weighted echo-planar MR imaging was performed with a 15-T MR unit in 97 head and neck lesions in 97 patients Images were obtained with a diffusion-weighted factor, factor b, of 0, 500, and 1,000 sec/mm2, and an ADC map was constructed The ADCs of lesions, cerebrospinal fluid, and spinal cord were calculated RESULTS: Acceptable images for ADC measurement were obtained in 81 (84%) patients The mean ADC of malignant lymphomas, (066 ± 017[SD]) × 10−3 mm2/sec (n = 13), was significantly smaller (P < 001) than that of carcinomas The mean ADC of carcinomas, (113 ± 043) × 10−3 mm2/sec (n = 36), was significantly smaller (P = 002) than that of benign solid tumors The mean ADC of benign solid tumors, (156 ± 051) × 10−3 mm2/sec (n = 22), was significantly smaller (P = 035) t
531 citations
TL;DR: The potential of high signal-to-noise ratio images with low anatomic noise, which are obtainable at dose levels comparable to those for mammography, suggests that dedicated breast CT should be studied further for its potential in breast cancer screening and diagnosis.
Abstract: PURPOSE: To evaluate the feasibility of breast computed tomography (CT) in terms of radiation dose and image quality. MATERIALS AND METHODS: Validated Monte Carlo simulation techniques were used to estimate the average glandular dose (AGD). The calculated photon fluence at the detector for high-quality abdominal CT (120 kVp, 300 mAs, 5-mm section thickness) was the benchmark for assessing the milliampere seconds and corresponding radiation dose necessary for breast CT. Image noise was measured by using a 10-cm-diameter cylinder imaged with a clinical CT scanner at 10–300 mAs for 80, 100, and 120 kVp. A cadaveric breast was imaged in the coronal plane to approximate the acquisition geometry of a proposed breast CT scanner. RESULTS: The AGD for 80-kVp breast CT was comparable to that for two-view mammography of 5-cm breasts (compressed breast thickness). For thicker breasts, the breast CT dose was about one-third less than that for two-view mammography. The maximum dose at mammography assessed in 1-mm3 voxe...
526 citations
TL;DR: The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin concentration images of the female breast that were formed with model-based reconstruction of near-infrared intensity-modulated tomographic data.
Abstract: The authors describe what is, to the best of their knowledge, the first quantitative hemoglobin concentration images of the female breast that were formed with model-based reconstruction of near-in...
500 citations
TL;DR: CT colonography has excellent sensitivity for the detection of clinically important colorectal polyps and cancer.
Abstract: PURPOSE: To determine the sensitivity and specificity of computed tomographic (CT) colonography for colorectal polyp and cancer detection by using colonoscopy as the reference standard. MATERIALS AND METHODS: Three hundred patients underwent CT colonography followed by standard colonoscopy. Bowel preparation consisted of magnesium citrate and polyethylene glycol. After colonic air insufflation, patients underwent scanning in the supine and prone positions with 3-mm collimation during a single breath hold. The transverse CT images, sagittal and coronal reformations, and three-dimensional endoluminal images were interpreted by two radiologists independently, and then a consensus reading was performed. CT colonographic findings were correlated with standard colonoscopic and histologic findings. RESULTS: The overall sensitivity and specificity of CT colonography for polyp detection were 90.1% (164 of 182) and 72.0% (85 of 118), respectively. By using direct polyp matching, the overall sensitivity was 69.7% (3...
497 citations
TL;DR: The automated method allowed rapid identification of brain and tumor tissue with an accuracy and reproducibility comparable to those of manual segmentation, making automated segmentation practical for low-grade gliomas and meningiomas.
Abstract: An automated brain tumor segmentation method was developed and validated against manual segmentation with three-dimensional magnetic resonance images in 20 patients with meningiomas and low-grade gliomas. The automated method (operator time, 5-10 minutes) allowed rapid identification of brain and tumor tissue with an accuracy and reproducibility comparable to those of manual segmentation (operator time, 3-5 hours), making automated segmentation practical for low-grade gliomas and meningiomas.
TL;DR: Improved imaging techniques are needed to enable reliable identification of high-risk plaques that lead to cerebrovascular events and the use of carotid MR to evaluate plaque morphology and composition.
Abstract: Measurement of vessel stenosis by using ultrasonography or angiography remains the principal method for determining the severity of carotid atherosclerosis and the need for endarterectomy. The ipsilateral stroke rate, however—even in patients with severely stenotic vessels—is relatively low, which suggests that the amount of luminal narrowing may not represent the optimal means of assessing clinical risk. As a result, some patients may undergo unnecessary surgery. Improved imaging techniques are, therefore, needed to enable reliable identification of high-risk plaques that lead to cerebrovascular events. High-spatial-resolution magnetic resonance (MR) imaging has been described as one promising modality for this purpose, because the technique allows direct visualization of diseased vessel wall and can be used to characterize the morphology of individual atherosclerotic carotid plaques. The purpose of this report is to review the current state of carotid plaque MR imaging and the use of carotid MR to evalu...
TL;DR: In this article, a multicenter retrospective study accrued 1,083 consecutive cases of breast cancer detected at screening mammography and evaluated the ability of computer-aided detection (CAD) to mark the missed cancers.
Abstract: PURPOSE: To retrospectively determine the mammographic characteristics of cancers missed at screening mammography and assess the ability of computer-aided detection (CAD) to mark the missed cancers. MATERIALS AND METHODS: A multicenter retrospective study accrued 1,083 consecutive cases of breast cancer detected at screening mammography. Prior mammograms were available in 427 cases. Of these, 286 had lesions visible in retrospect. The 286 cases underwent blinded review by panels of radiologists; a majority recommended recall for 112 cases. Two experienced radiologists compared prior mammograms in 110 of these cases with the subsequent screening mammograms (when cancer was detected), noting mammographic characteristics of breast density, lesion type, size, morphology, and subjective reasons for possible miss. The prior mammograms were then analyzed with a CAD program. RESULTS: There were 110 patients with 115 cancers. On the prior mammograms with missed cancers, 35 (30%) of the 115 lesions were calcificati...
TL;DR: Segmented cine true FISP MR imaging generated high-contrast MR images of the heart in healthy subjects and in patients with heart disease and produced image quality superior to that with cine FLASH MR imaging.
Abstract: In five healthy subjects and 18 patients, cine magnetic resonance (MR) imaging of the heart was performed with a true fast imaging with steady-state precession (FISP) sequence. Results were compared both quantitatively and qualitatively with those at cine fast low-angle shot (FLASH) MR imaging. The blood-myocardial contrast-to-noise ratio (CNR) was 2.0 times higher and the normalized (for measurement time and pixel size) blood-myocardial CNR was 4.0 times higher for true FISP compared with FLASH MR imaging. Qualitative scores for image quality were significantly higher with true FISP MR imaging. Segmented cine true FISP MR imaging generated high-contrast MR images of the heart in healthy subjects and in patients with heart disease and produced image quality superior to that with cine FLASH MR imaging.
TL;DR: Changes in magnitude and anisotropy of water diffusion follow stereotypical time courses during brain development that can be empirically described with multiexponential regression models, which suggests that quantitative scalar parameters derived from diffusion-tensor MR imaging may provide clinically useful developmental milestones for brain maturity.
Abstract: PURPOSE: To characterize the maturational changes in water diffusion within central gray matter nuclei and central white matter pathways of the human brain by using diffusion-tensor magnetic resonance (MR) imaging. MATERIALS AND METHODS: Retrospective analysis of normal MR examination findings in 153 subjects (age range, 1 day to 11 years) referred for clinical neuroimaging was performed. All studies included diffusion tensor-encoded echo-planar MR imaging. Isotropic diffusion coefficient (D) and diffusion anisotropy (Aσ) were measured in the corpus callosum, internal capsule, caudate nucleus, lentiform nucleus, and thalamus. RESULTS: D exhibited biexponential decay with age in gray and white matter regions, except for monoexponential decay in the genu of the corpus callosum. There was a steep nonlinear increase of Aσ in white matter tracts that paralleled the time course of the decline in D. In basal ganglia, only a small linear increase in Aσ was observed in patients. Aσ changes in the thalamus were ...
TL;DR: Bilateral whole-breast US, when performed in patients with dense (BI-RADS category 3 or 4 density) breast tissue, is useful in detecting breast cancer not discovered with mammography or clinical breast examination.
Abstract: PURPOSE: To evaluate the clinical utility of bilateral whole-breast ultrasonography (US) as an adjunct examination to mammography in asymptomatic women with dense (Breast Imaging Reporting and Data System [BI-RADS] density category 3 or 4) breast tissue. MATERIALS AND METHODS: Between July 1998 and April 2000, 1,862 patients with negative findings at clinical examinations, negative mammographic results, and breast tissue with BI-RADS category 3 or 4 density were evaluated with bilateral whole-breast US for occult cystic and solid masses, areas of architectural distortion, and acoustic shadowing. Suggestive findings were compared with tissue diagnoses from US-guided core biopsy specimens. US was initially performed by a US or a mammography technologist. The average time to perform the examination was approximately 10 minutes. Abnormal findings were corroborated by a fellowship-trained breast-imaging radiologist. RESULTS: In the 1,862 women examined with bilateral whole-breast US, 57 biopsies were recommend...
TL;DR: Short- and long-axis cine magnetic resonance (MR) images were obtained with a standard fast low-angle shot, or FLASH, sequence and a first-generation true fast imaging with steady-state precession (FISP) sequence on a 1.5-T MR imager.
Abstract: Short- and long-axis cine magnetic resonance (MR) images were obtained with a standard fast low-angle shot, or FLASH, sequence and a first-generation true fast imaging with steady-state precession (FISP) sequence on a 1.5-T MR imager. Contrast-to-noise ratios and volumetric left ventricular measurements were compared for manual and automatic segmentation. True FISP images were associated with significantly (P < .01) higher contrast-to-noise ratios and allowed better detection of the endocardial border. True FISP images were provided with short acquisition times and excellent contrast between the myocardium and the ventricular lumen.
TL;DR: The use of nonspecific extracellular gadolinium chelates, reticuloendothelial system-specific iron oxide particulate agents, hepatocytes-selective agents, and combined perfusion and hepatocyte- selective agents are described.
Abstract: A variety of different categories of contrast agents, and within each category a number of individual agents, are currently available for clinical use in magnetic resonance (MR) imaging of the liver. In this review, the use of nonspecific extracellular gadolinium chelates, reticuloendothelial system-specific iron oxide particulate agents, hepatocyte-selective agents, and combined perfusion and hepatocyte-selective agents are described. Most clinical experience is with nonspecific extracellular gadolinium chelates. The relatively low cost, safety, good patient tolerance, and ability to help detect and characterize a wide range of liver diseases have rendered gadolinium chelates as commonly used agents. Reticuloendothelial system-specific agents improve lesion detection by decreasing the signal intensity of background liver on T2-weighted MR images, which increases the conspicuity of focal hepatic lesions with negligible reticuloendothelial cells (eg, metastases). Hepatocyte-selective agents increase the signal intensity of background liver on T1-weighted images, which increases the conspicuity of focal lesions that do not contain hepatocytes (eg, metastases). The clinical application of the different categories of contrast agents, techniques for their administration, sequences to be used, and appearances of common entities on contrast agent-enhanced studies are described.
TL;DR: DCIS underestimations were 1.9 times more frequent with masses than with calcifications, 1.8 times more Frequent with large-core biopsy than with vacuum-assisted biopsy, and 1.5 timesMore frequent with 10 or fewer specimens per lesion than with more than 10 specimens perLesion.
Abstract: PURPOSE: To measure the effect of biopsy device, probe size, mammographic lesion type, lesion size, and number of samples obtained per lesion on the ductal carcinoma in situ (DCIS) underestimation rate. MATERIALS AND METHODS: Nonpalpable breast lesions at 16 institutions received a histologic diagnosis of DCIS after 14-gauge automated large-core biopsy in 373 lesions and after 14- or 11-gauge directional vacuum-assisted biopsy in 953 lesions. The presence of histopathologic invasive carcinoma was noted at subsequent surgical biopsy. RESULTS: By performing the χ2 test, independent significant DCIS underestimation rates by biopsy device were 20.4% (76 of 373) of lesions diagnosed at large-core biopsy and 11.2% (107 of 953) of lesions diagnosed at vacuum-assisted biopsy (P < .001); by lesion type, 24.3% (35 of 144) of masses and 12.5% (148 of 1,182) of microcalcifications (P < .001); and by number of specimens per lesion, 17.5% (88 of 502) with 10 or fewer specimens and 11.5% (92 of 799) with greater than 10...
TL;DR: Thin-section CT findings of peripheral lung adenocarcinomas correlate well with histologic prognostic factors and showed a significantly better prognosis than those with GGO components less than 50%.
Abstract: PURPOSE: To evaluate the prognostic importance of thin-section computed tomographic (CT) findings of peripheral lung adenocarcinomas. MATERIALS AND METHODS: The subjects were 127 patients with adenocarcinomas smaller than 3 cm in largest diameter who underwent at least a lobectomy with hilar and mediastinal lymphadenectomy. The margin characteristics of nodules and the extent of ground-glass opacity (GGO) within the nodules at preoperative thin-section CT were analyzed retrospectively. Regional lymph node metastasis (LNM) and vessel invasion (VI) were histologically examined in surgical specimens. Survival curves were calculated according to the Kaplan-Meier method. RESULTS: The frequencies of LNM (4% [1 of 24]) and VI (13% [three of 24]) in adenocarcinomas with GGO components of more than 50% were significantly lower than those with GGO components of less than 10% (LNM, P < .05; VI, P < .01). The patients with GGO components of more than 50% showed a significantly better prognosis than those with GGO com...
TL;DR: Multi-detector row CT with reconstructed scans of 1.25-mm-thick sections enables accurate analysis of peripheral pulmonary arteries down to the fifth order on spiral CT angiograms.
Abstract: PURPOSE: To analyze the influence of multi–detector row spiral computed tomography (CT) on identification of peripheral pulmonary arteries. MATERIALS AND METHODS: Peripheral pulmonary arteries were analyzed on optimally opacified contrast material–enhanced spiral CT angiograms in 30 patients devoid of pleuroparenchymal disease who underwent scanning with multi–detector row CT (collimation, 4 × 1 mm; pitch, 1.7–2.0; scanning time, 0.5 second). Two series of scans were systematically generated from each data set, 1.25-mm-thick (group 1) and 3-mm-thick (group 2) sections, leading to the analysis of 600 segmental (20 arteries per patient), 1,200 subsegmental (40 arteries per patient), 2,400 fifth-order (80 arteries per patient), and 4,800 sixth-order (160 arteries per patient) pulmonary arteries in each group. RESULTS: Multi–detector row CT with reconstructed scans of 1.25-mm-thick sections (group 1) allowed (a) analysis of a significantly higher percentage of subsegmental arteries (94% in group 1 vs 82% in g...
TL;DR: In this article, the authors reviewed the clinical and radiologic features of internal hernia and derived useful radiographic and CT criteria to assist in diagnosis, including evidence of small-bowel obstruction, clustering of small bowel; stretched, displaced, crowded, and engorged mesenteric vessels; and displacement of other bowel segments.
Abstract: PURPOSE: To review the clinical and radiologic features of internal hernia and to derive useful radiographic and CT criteria to assist in diagnosis. MATERIALS AND METHODS: Retrospective review of medical records revealed 17 patients with surgically proved internal hernia (three paraduodenal, 14 transmesenteric) who had 15 computed tomographic (CT) scans and three small-bowel follow-through (SBFT) images. RESULTS: CT signs common to all types of internal hernia included evidence of small-bowel obstruction; clustering of small bowel; stretched, displaced, crowded, and engorged mesenteric vessels; and displacement of other bowel segments, especially the transverse colon and fourth portion of the duodenum. Left-sided paraduodenal hernias demonstrated a saclike mass of small-bowel loops interposed between the stomach and pancreatic tail and a posterior mass effect on the stomach. All three paraduodenal hernias were diagnosed confidently at retrospective review of CT and SBFT findings. Transmesenteric hernias d...
TL;DR: FFDM has so far led to fewer recalls than SFM, but this difference was not significant and no difference in cancer detection rate has yet been observed between FFDM and SFM.
Abstract: PURPOSE: To prospectively compare full-field digital mammography (FFDM) with screen-film mammography (SFM) for cancer detection in a screening population. MATERIALS AND METHODS: At two institutions, 4,945 FFDM examinations were performed in women aged 40 years and older presenting for SFM. Two views of each breast were acquired with each modality. SFM and FFDM images were interpreted independently. Findings detected with either SFM or FFDM were evaluated with additional imaging and, if warranted, biopsy. RESULTS: Patients in the study underwent 152 biopsies, which resulted in the diagnosis of 35 breast cancers. Twenty-two cancers were detected with SFM and 21 with FFDM. Four were interval cancers that became palpable within 1 year of screening and were considered false-negative findings with both modalities. The difference in cancer detection rate was not significant. FFDM had a significantly lower recall rate (11.5%; 568 of 4,945) than SFM (13.8%; 685 of 4,945) (P < .001, McNemar χ2 model; P < .03, gener...
TL;DR: After isChemic stroke, x-ray hypoattenuation at CT is highly specific for irreversible ischemic brain damage if detection occurs within the first 6 hours.
Abstract: PURPOSE: To assess the capability of computed tomography (CT) in the prediction of irreversible ischemic brain damage and its association with the clinical course within 6 hours of stroke onset. MATERIALS AND METHODS: Serial CT scans obtained within 6 hours of stroke onset, at 22–96 hours (median, 1 day), and at 2–36 days (median, 7 days) after symptom onset in 786 patients with ischemic stroke were prospectively studied, and follow-up CT scans were used as the reference. Clinical variables were assessed prospectively and independently of CT evaluation. RESULTS: The specificity and positive predictive value of ischemic edema at baseline CT for brain infarcts were 85% (95% CI: 77%, 91%) and 96% (95% CI: 94%, 98%), respectively. Sensitivity and negative predictive values were 64% (95% CI: 60%, 67%) and 27% (95% CI: 23%, 32%), respectively. Patients without early CT findings were less severely affected (P < .001), developed smaller infarcts (P < .001), had fewer intracranial bleeding events (P < .001), and h...
TL;DR: Hippocampal ADC was significantly different between control subjects and MCI patients, many of whom likely have preclinical Alzheimer disease, which may reflect early ultrastructural changes in the progression of Alzheimer disease.
Abstract: PURPOSE: To compare the regional diffusivity of water in the brains of normally aging elderly people and patients with mild cognitive impairment (MCI) or Alzheimer disease. MATERIALS AND METHODS: Magnetic resonance images were obtained in 21 patients with Alzheimer disease, 19 patients with MCI, and 55 normally aging elderly control subjects without evidence of cognitive impairment. Regions of interest were drawn to compare the apparent diffusion coefficient (ADC) and the anisotropy index (AI) in frontal, parietal, temporal, occipital, anterior, and posterior cingulate white matter (WM), and the thalami and hippocampi. RESULTS: Hippocampal ADC was higher in MCI and Alzheimer disease patients than in control subjects. ADC of the temporal stem and posterior cingulate, occipital, and parietal WM was higher in Alzheimer disease patients than in control subjects. Except for occipital AI, which was lower in MCI patients than in control subjects, there were no differences in AI among the three groups for any of ...
TL;DR: MR imaging is insensitive for the diagnosis of small (<2-cm) HCCs and DNS.
Abstract: PURPOSE: To determine the sensitivity and specificity of magnetic resonance (MR) imaging for detection of hepatocellular carcinoma (HCC) and dysplastic nodules (DNs) by using explantation correlation in patients with cirrhosis and no known HCC. MATERIALS AND METHODS: Seventy-one patients without a known history of HCC who underwent MR imaging and subsequent transplantation within 90 days were examined. Breath-hold turbo short inversion time inversion-recovery and/or T2-weighted turbo spin-echo MR images were obtained. Dynamic two- or three-dimensional gadolinium-enhanced gradient-echo MR images were obtained in the hepatic arterial, portal venous, and equilibrium phases. Prospective MR image interpretations were compared directly with explanted liver pathologic results. RESULTS: Eleven (15%) of 71 patients had hepatic malignancies; MR imaging enabled diagnosis of tumor in six (54%) of 11 patients. On a lesion-by-lesion basis, MR imaging depicted 11 of 20 hepatic neoplasms, for an overall sensitivity of 55...
TL;DR: In this article, the authors evaluated the accuracy of magnetic resonance (MR) imaging with a quadrature phasedarray coil for the detection of anal fistulas and evaluated the additional clinical value of preoperative MR imaging, as compared with surgery alone.
Abstract: PURPOSE: To evaluate the accuracy of magnetic resonance (MR) imaging with a quadrature phased-array coil for the detection of anal fistulas and to evaluate the additional clinical value of preoperative MR imaging, as compared with surgery alone. MATERIALS AND METHODS: Fifty-six patients with anal fistulas underwent high-spatial-resolution MR imaging. Twenty-four had a primary fistula; 17, a recurrent fistula; and 15, a fistula associated with Crohn disease. MR imaging findings were withheld from the surgeon until surgery ended and verified, and surgery continued when required. RESULTS: MR imaging provided important additional information in 12 (21%) of 56 patients. In patients with Crohn disease, the benefit was 40% (six of 15); in patients with recurrent fistulas, 24% (four of 17); and in patients with primary fistulas, 8% (two of 24). The difference between patients with or without Crohn disease and between patients with a simple fistula versus the rest was significant (P < .05). The sensitivity and spe...
TL;DR: CT angiography and MRAngiography have limited sensitivity in the detection of small aneurysms but good interobserver agreement and there is no significant difference in diagnostic performance between the noninvasive modalities.
Abstract: PURPOSE: To compare computed tomographic (CT) angiography and magnetic resonance (MR) angiography with intraarterial digital subtraction angiography (DSA) in the detection of intracranial aneurysms. MATERIALS AND METHODS: One hundred forty-two patients underwent intraarterial DSA to detect aneurysms. CT angiography, three-dimensional time-of-flight MR angiography, and intraarterial DSA were performed contemporaneously. Film hard-copy images and maximum intensity projection reconstructions of the CT angiograms and MR angiograms were reviewed at different times. RESULTS: The accuracy per patient for the best observer was 0.87 at CT angiography and 0.85 at MR angiography. The accuracy per aneurysm for the best observer was 0.73 at CT angiography and 0.67 at MR angiography. Differences between readers and modalities were not significant. Interobserver agreement was good: κ value of 0.73 for CT angiography and of 0.74 for MR angiography. The sensitivity for detection of aneurysms smaller than 5 mm was 0.57 for...
TL;DR: Moderate and severe endplate abnormalities appear be useful in the prediction of painful disk derangement in patients with symptomatic low back pain.
Abstract: PURPOSE: To investigate the predictive value of magnetic resonance (MR) imaging of abnormalities of the lumbar intervertebral disks, particularly with adjacent endplate changes, to predict symptomatic disk derangement, with discography as the standard. MATERIALS AND METHODS: Fifty patients aged 28–50 years with chronic low back pain and without radicular leg pain underwent prospective clinical examination and sagittal T1- and T2-weighted and transverse T2-weighted MR imaging. Subsequently, patients underwent lumbar discography with a pain provocation test (116 disks). MR images were evaluated for disk degeneration, a high-signal-intensity zone, and endplate abnormalities. Results of pain provocation at discography were rated independently of the image findings as concordant or as nonconcordant or painless. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the clinical relevance of MR abnormalities. RESULTS: Normal disks on MR images we...
TL;DR: Although the number of cases was small, three chondroblastomas, one sarcoidosis, and one Langerhans cell histiocytosis showed levels of FDG accumulation as high as that of osteosarcomas, suggesting that consideration of histologic subtypes should be included in analysis of SUV at FDG PET of primary bone tumors.
Abstract: PURPOSE: To evaluate the standardized uptake value (SUV) of 2-[fluorine-18]fluoro-2-deoxy-d-glucose (FDG) at positron emission tomography (PET) in the differentiation of benign from malignant bone lesions. MATERIALS AND METHODS: Fifty-two (19 malignant, 33 benign) primary bone lesions were examined with FDG PET prior to tissue diagnosis. The SUVs were calculated and compared between benign and malignant lesions and among histologic subgroups that included more than four cases. RESULTS: There was a statistically significant difference in SUV between benign (2.18 ± 1.52 [SD]) and malignant (4.34 ± 3.19) lesions in total (P = .002). However, giant cell tumors (n = 5; SUV, 4.64 ± 1.05) showed significantly higher SUV than chondrosarcomas (n = 7; SUV, 2.23 ± 0.74) (P = .036, adjusted for multiple comparisons) and had no statistically significant difference in SUV compared with osteosarcomas (n = 6; SUV, 3.07 ± 0.96) (P = .171). There was no statistically significant difference in SUV between fibrous dysplasias...