Investigative Radiology (INVEST RADIOL)

Publisher: Association of University Radiologists, Lippincott, Williams & Wilkins

Journal description

Investigative Radiology publishes original, peer-reviewed reports on clinical and laboratory investigations in diagnostic imaging, the diagnostic use of radioactive isotopes, computed tomography, positron emission tomography, magnetic resonance imaging, ultrasound, digital subtraction angiography, and related modalities. Emphasis is on early and timely publication. Primarily research-oriented, the journal also includes a wide variety of features of interest to clinical radiologists.

Current impact factor: 4.44

Impact Factor Rankings

2016 Impact Factor Available summer 2017
2014 / 2015 Impact Factor 4.437
2013 Impact Factor 4.453
2012 Impact Factor 5.46
2011 Impact Factor 4.593
2010 Impact Factor 4.665
2009 Impact Factor 4.85
2008 Impact Factor 5.289
2007 Impact Factor 4.234
2006 Impact Factor 3.398
2005 Impact Factor 3.173
2004 Impact Factor 2.32
2003 Impact Factor 1.99
2002 Impact Factor 2.67
2001 Impact Factor 2.298
2000 Impact Factor 1.41
1999 Impact Factor 1.757
1998 Impact Factor 0.922
1997 Impact Factor 0.915
1996 Impact Factor 0.89
1995 Impact Factor 0.712
1994 Impact Factor 0.841
1993 Impact Factor 0.776
1992 Impact Factor 0.658

Impact factor over time

Impact factor
Year

Additional details

5-year impact 4.42
Cited half-life 6.80
Immediacy index 0.75
Eigenfactor 0.01
Article influence 1.53
Website Investigative Radiology website
Other titles Investigative radiology
ISSN 0020-9996
OCLC 1753822
Material type Periodical, Internet resource
Document type Journal / Magazine / Newspaper, Internet Resource

Publisher details

Lippincott, Williams & Wilkins

  • Pre-print
    • Author can archive a pre-print version
  • Post-print
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  • Restrictions
    • 12 months embargo
  • Conditions
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    • Pre-print must be removed upon acceptance for publication
    • Post-print may be deposited in personal website or institutional repository
    • Publisher's version/PDF cannot be used
    • Must include statement that it is not the final published version
    • Published source must be acknowledged with full citation
    • Set statement to accompany deposit
    • Must link to publisher version
    • NIH authors will have their accepted manuscripts transmitted to PubMed Central on their behalf after a 12 months embargo (see policy for details)
    • Wellcome Trust and HHMI authors will have their accepted manuscripts transmitted to PubMed Central on their behalf after a 6 months embargo (see policy for details)
    • Publisher last reviewed on 19/03/2015
  • Classification
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Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives: Ductal carcinoma in situ (DCIS) is a risk factor for incomplete resection of breast cancer. Especially, extensive DCIS (E-DCIS) or extensive intraductal component often results in positive resection margins. Detecting DCIS around breast cancer before treatment may therefore alter surgery. The purpose of this study was to develop a prediction model for E-DCIS around early-stage invasive breast cancer, using clinicohistopathological and dynamic contrast-enhanced magnetic resonance imaging (MRI) features. Materials and methods: Dynamic contrast-enhanced MRI and local excision were performed in 322 patients with 326 ductal carcinomas. Tumors were segmented from dynamic contrast-enhanced MRI, followed by 3-dimensional extension of the margins with 10 mm. Amount of fibroglandular tissue (FGT) and enhancement features in these extended margins were automatically extracted from the MRI scans. Clinicohistopathological features were also obtained. Principal component analysis and multivariable logistic regression were used to develop a prediction model for E-DCIS. Discrimination and calibration were assessed, and bootstrapping was applied for internal validation. Results: Extensive DCIS occurred in 48 (14.7%) of 326 tumors. Incomplete resection occurred in 56.3% of these E-DCIS-positive versus 9.0% of E-DCIS-negative tumors (P < 0.001). Five components with eigenvalue exceeding 1 were identified; 2 were significantly associated with E-DCIS. The first, positively associated, component expressed early and overall enhancement in the 10-mm tissue margin surrounding the MRI-visible tumor. The second, positively associated, component expressed human epidermal growth factor receptor 2 and amount of FGT around the MRI-visible tumor. The area under the curve value was 0.79 (0.76 after bootstrapping). Conclusions: Human epidermal growth factor receptor 2 status, early and overall enhancement in the 10-mm margin around the MRI-visible tumor, and amount of FGT in the 10 mm around the MRI-visible tumor were associated with E-DCIS.
    No preview · Article · Feb 2016 · Investigative Radiology
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    ABSTRACT: Objectives: The objective of this study was to increase the spatial and temporal resolution of dynamic 3-dimensional (3D) magnetic resonance imaging (MRI) of lung volumes and diaphragm motion. To achieve this goal, we evaluate the utility of the proposed blind compressed sensing (BCS) algorithm to recover data from highly undersampled measurements. Materials and methods: We evaluated the performance of the BCS scheme to recover dynamic data sets from retrospectively and prospectively undersampled measurements. We also compared its performance against that of view-sharing, the nuclear norm minimization scheme, and the l1 Fourier sparsity regularization scheme. Quantitative experiments were performed on a healthy subject using a fully sampled 2D data set with uniform radial sampling, which was retrospectively undersampled with 16 radial spokes per frame to correspond to an undersampling factor of 8. The images obtained from the 4 reconstruction schemes were compared with the fully sampled data using mean square error and normalized high-frequency error metrics. The schemes were also compared using prospective 3D data acquired on a Siemens 3 T TIM TRIO MRI scanner on 8 healthy subjects during free breathing. Two expert cardiothoracic radiologists (R1 and R2) qualitatively evaluated the reconstructed 3D data sets using a 5-point scale (0-4) on the basis of spatial resolution, temporal resolution, and presence of aliasing artifacts. Results: The BCS scheme gives better reconstructions (mean square error = 0.0232 and normalized high frequency = 0.133) than the other schemes in the 2D retrospective undersampling experiments, producing minimally distorted reconstructions up to an acceleration factor of 8 (16 radial spokes per frame). The prospective 3D experiments show that the BCS scheme provides visually improved reconstructions than the other schemes do. The BCS scheme provides improved qualitative scores over nuclear norm and l1 Fourier sparsity regularization schemes in the temporal blurring and spatial blurring categories. The qualitative scores for aliasing artifacts in the images reconstructed by nuclear norm scheme and BCS scheme are comparable.The comparisons of the tidal volume changes also show that the BCS scheme has less temporal blurring as compared with the nuclear norm minimization scheme and the l1 Fourier sparsity regularization scheme. The minute ventilation estimated by BCS for tidal breathing in supine position (4 L/min) and the measured supine inspiratory capacity (1.5 L) is in good correlation with the literature. The improved performance of BCS can be explained by its ability to efficiently adapt to the data, thus providing a richer representation of the signal. Conclusion: The feasibility of the BCS scheme was demonstrated for dynamic 3D free breathing MRI of lung volumes and diaphragm motion. A temporal resolution of ~500 milliseconds, spatial resolution of 2.7 × 2.7 × 10 mm, with whole lung coverage (16 slices) was achieved using the BCS scheme.
    No preview · Article · Feb 2016 · Investigative Radiology
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    ABSTRACT: Objective: The purpose of this study was to determine whether gadolinium (Gd) is deposited in brain and bone tissues in patients receiving only non-Group 1 agents, either macrocyclic or linear protein interacting Gd-based contrast agents, with normal renal function. Group 1 agents are linear agents most associated with nephrogenic systemic fibrosis that the US Federal Drug Administration has defined as contraindicated in patients at risk for this disease. Materials and methods: This study was institutional review board approved and Health Insurance Portability and Accountability Act compliant for retrospective review of records and also had signed autopsy consent authorizing use of decedent's tissue in research studies. Tissue samples were collected from 9 decedents undergoing autopsy who had contrast-enhanced magnetic resonance imaging (MRI) with only single agent exposure to a non-Group 1 Gd-based contrast agent. Decedents with only noncontrast MRI or no MRI served as controls. Multiple brain areas, including globus pallidus and dentate nucleus, as well as bone and skin, were sampled and analyzed for Gd using inductively coupled plasma mass spectrometry. Gadolinium levels were compared between groups of decedents using the Mann-Whitney test and between brain and bone tissues of the same cases using the Wilcoxon signed-rank test. Results: Of the 9 decedents, 5 received gadoteridol (ProHance; Bracco Diagnostics, Princeton, NJ), 2 received gadobutrol (Gadovist; Bayer Healthcare, Whippany, NJ), and 1 each had gadobenate (MultiHance; Bracco Diagnostics) and gadoxetate (Eovist; Bayer Healthcare). Gadolinium was found with all agents in all brain areas sampled with highest levels in globus pallidus and dentate. Bone levels measured 23 times higher (median) than brain levels (P = 0.008 for bone vs globus pallidus) and showed a significant correlation (r = 0.81, P = 0.022). In controls, Gd levels in the brain were at or below limits of measurement and were significantly lower compared with study cases (P = 0.005 for globus pallidus). Conclusion: Gadolinium deposition in normal brain and bone tissue occurs with macrocyclic and linear protein interacting agents in patients with normal renal function. Deposition of Gd in cortical bone occurs at much higher levels compared with brain tissue and shows a notable correlation between the two. Thus, the bone may serve as a surrogate to estimate brain deposition if brain Gd were to become a useful clinical or research marker.
    No preview · Article · Feb 2016 · Investigative Radiology
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    ABSTRACT: Objective: The aim of this study was to compare quantitative and semiquantitative parameters (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], image quality, diagnostic confidence) from a standard brain magnetic resonance imaging examination encompassing common neurological disorders such as demyelinating disease, gliomas, cerebrovascular disease, and epilepsy, with comparable sequence protocols and acquisition times at 3 T and at 7 T. Materials and methods: Ten healthy volunteers and 4 subgroups of 40 patients in total underwent comparable magnetic resonance protocols with standard diffusion-weighted imaging, 2D and 3D turbo spin echo, 2D and 3D gradient echo and susceptibility-weighted imaging of the brain (10 sequences) at 3 T and 7 T. The subgroups comprised patients with either lesional (n = 5) or nonlesional (n = 4) epilepsy, intracerebral tumors (n = 11), demyelinating disease (n = 11) (relapsing-remitting multiple sclerosis [MS, n = 9], secondary progressive MS [n = 1], demyelinating disease not further specified [n = 1]), or chronic cerebrovascular disorders [n = 9]). For quantitative analysis, SNR and CNR were determined. For a semiquantitative assessment of the diagnostic confidence, a 10-point scale diagnostic confidence score (DCS) was applied. Two experienced radiologists with additional qualification in neuroradiology independently assessed, blinded to the field strength, 3 pathology-specific imaging criteria in each of the 4 disease groups and rated their diagnostic confidence. The overall image quality was semiquantitatively assessed using a 4-point scale taking into account whether diagnostic decision making was hampered by artifacts or not. Results: Without correction for spatial resolution, SNR was higher at 3 T except in the T2 SPACE 3D, DWI single shot, and DIR SPACE 3D sequences. The SNR corrected by the ratio of 3 T/7 T voxel sizes was higher at 7 T than at 3 T in 10 of 11 sequences (all except for T1 MP2RAGE 3D).In CNR, there was a wide variation between sequences and patient cohorts, but average CNR values were broadly similar at 3 T and 7 T.DCS values for all 4 pathologic entities were higher at 7 T than at 3 T. The DCS was significantly higher at 7 T for diagnosis and exclusion of cortical lesions in vascular disease. A tendency to higher DCS at 7 T for cortical lesions in MS was observed, and for the depiction of a central vein and iron deposits within MS lesions. Despite motion artifacts, DCS values were higher at 7 T for the diagnosis and exclusion of hippocampal sclerosis in mesial temporal lobe epilepsy (improved detection of the hippocampal subunits). Interrater agreement was 69.7% at 3 T and 93.3% at 7 T. There was no significant difference in the overall image quality score between 3 T and 7 T taking into account whether diagnostic decision making was hampered by artifacts or not. Conclusions: Ultra-high-field magnetic resonance imaging at 7 T compared with 3 T yielded an improved diagnostic confidence in the most frequently encountered neurologic disorders. Higher spatial resolution and contrast were identified as the main contributory factors.
    No preview · Article · Feb 2016 · Investigative Radiology
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    ABSTRACT: Objective: The aim of this study was to assess whether a short breath-hold technique can improve hepatic arterial phase (HAP) image quality in gadoxetic acid-enhanced magnetic resonance (MR) imaging compared with a conventional long breath-hold technique. Materials and methods: Institutional review board approval and patient consent were obtained for this prospective randomized control study. One hundred nineteen patients undergoing gadoxetic acid-enhanced MR imaging were randomly assigned to groups A or B. Group A patients underwent an 18-second long breath-hold MR technique (conventional VIBE [volumetric interpolated breath-hold examination] technique with GRAPPA [generalized autocalibrating partially parallel acquisition]), and group B patients underwent a 13-second short breath-hold MR technique (VIBE technique with CAIPIRINHA [controlled aliasing in parallel imaging results in higher acceleration]). Respiratory-related graphs of the precontrast and HAP were acquired. The breath-hold degree was graded based on the standard deviation (SD) value of respiratory waveforms. Gadoxetic acid-related dyspnea was defined as when the SD value of the HAP was 200 greater than that of the precontrast phase without degraded image quality in the portal and transitional phases (SD value of the HAP - SD value of the precontrast phase). The overall image quality and motion artifacts of the precontrast and HAP images were evaluated. The groups were compared using the Student t or Fisher exact test, as appropriate. Results: The incidence of breath-holding difficulty (breath-hold grades 3 and 4) during the HAP was 43.6% (27/62) and 36.8% (21/57) for group A and B, respectively. The SD value during the precontrast phase and the SD value difference between the precontrast and HAP were both significantly higher in group A than in group B (P = 0.047 and P = 0.023, respectively). Gadoxetic acid-related dyspnea was seen in 19.4% (12/62) of group A and 7.0% (4/57) of group B. Group B showed better precontrast and HAP image quality than group A (P < 0.001). Degraded HAP (overall image quality ≥4) was observed in 9.7% (6/62) and 3.5% (2/57) of group A and B, respectively. Conclusions: The short breath-hold MR technique, CAIPIRINHA, showed better HAP image quality with less degraded HAP and a lower incidence of breath-hold difficulty and gadoxetic acid-related dyspnea than the conventional long breath-hold technique.
    No preview · Article · Jan 2016 · Investigative Radiology
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    ABSTRACT: Objectives: The purpose of the present study was to compare periodically rotated overlapping parallel lines with enhanced reconstruction-type turbo spin echo diffusion-weighted imaging (pTSE-DWI) and readout-segmented echo planar imaging (rsEPI-DWI) with single-shot echo planar imaging (ssEPI-DWI) in a 7 T human MR system. We evaluated the signal-to-noise ratio (SNR), image distortion, and apparent diffusion coefficient values in the human brain. Materials and methods: Six healthy volunteers were included in this study. The study protocol was approved by our institutional review board. All measurements were performed at 7 T using pTSE-DWI, rsEPI-DWI, and ssEPI-DWI sequences. The spatial resolution was 1.2 × 1.2 mm in-plane with a 3-mm slice thickness. Signal-to-noise ratio was measured using 2 scans. Results: The ssEPI-DWI sequence showed significant image blurring, whereas pTSE-DWI and rsEPI-DWI sequences demonstrated high image quality with low geometrical distortion compared with reference T2-weighted, turbo spin echo images. Signal loss in ventral regions near the air-filled paranasal sinus/nasal cavity was found in ssEPI-DWI and rsEPI-DWI but not pTSE-DWI. The apparent diffusion coefficient values for ssEPI-DWI were 824 ± 17 × 10 and 749 ± 25 × 10 mm/s in the gray matter and white matter, respectively; the values obtained for pTSE-DWI were 798 ± 21 × 10 and 865 ± 40 × 10 mm/s; and the values obtained for rsEPI-DWI were 730 ± 12 × 10 and 722 ± 25 × 10 mm/s. The pTSE-DWI images showed no additional distortion comparison to the T2-weighted images, but had a lower SNR than ssEPI-DWI and rsEPI-DWI. The rsEPI-DWI sequence provided high-quality images with minor distortion and a similar SNR to ssEPI-DWI. Conclusions: Our results suggest that the benefits of the rsEPI-DWI and pTSE-DWI sequences, in terms of SNR, image quality, and image distortion, appear to outweigh those of ssEPI-DWI. Thus, pTSE-DWI and rsEPI-DWI at 7 T have great potential use for clinical diagnoses. However, it is noteworthy that both sequences are limited by the scan time required. In addition, pTSE-DWI has limitations on the number of slices due to specific absorption rate. Overall, rsEPI-DWI is a favorable imaging sequence, taking into account the SNR and image quality at 7 T.
    No preview · Article · Jan 2016 · Investigative Radiology
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    ABSTRACT: Objective: The purpose of this study was to evaluate the feasibility of using integrated slice-by-slice shimming (iShim) for improving the image quality of whole-body diffusion-weighted imaging (WBDWI) in patients with plasma disorder at 3 T by comparing to WBDWI using a conventional shimming (3-dimensional [3D] shim) adjustment of each body station. Materials and methods: After approval by the local institutional review board, 2 healthy volunteers and 29 suspected patients with plasma disorder participated in this cross-sectional study. All participants were scanned by the same WBDWI protocol with iShim and 3D shim, consecutively. Body region-dependent signal-to-noise ratio (SNR) between iShim and 3D shim was compared in 2 volunteer scans. Body region-dependent shimming parameters, image quality, the number of suspicious lesions, and the agreement of apparent diffusion coefficient values were compared in 29 suspected patients with plasma disorder. Signal integrity between images acquired at adjacent bed positions, in sagittal reformats, which may be impaired by susceptibility effects, was assessed using an image quality score between 1 (worst) and 4 (best). Spatial displacement of diffusion-weighted images was calculated using a 3D turbo spin-echo acquisition as a reference. Results: For the SNR comparison in 2 volunteers, the iShim technique yielded 8-fold and 15-fold SNR improvements in the neck region (P < 0.05), while keeping a comparable SNR (ratio, 1 ± 0.2) performance in other body regions (P > 0.05). In the patient group, the mean score of image quality for iShim WBDWI was 3.69, and 76% of the cases showed unimpaired whole-body signal integrity, while in 3D shim WBDWI images, the mean image quality score was 1.93, and only 7% of the cases showed unimpaired whole-body signal integrity. The spatial displacement of diffusion-weighted images was on average reduced from 7.21 mm (3D shim) to 3.89 mm by using the iShim technique.Twenty-four of 72 suspicious lesions visible in iShim images of the neck region were missed on 3D shim images due to signal loss, while the number of focal lesions in the other body regions was comparable. With the 2 different shimming techniques, the agreement of apparent diffusion coefficient values of lesion and muscle in the head, thorax, abdomen, and pelvis regions was excellent (r > 0.75; P > 0.05), but there was a significant difference in the neck region (P < 0.05). Conclusions: The iShim technique is an effective method to reduce the negative impact of susceptibility effects at 3 T on whole-body diffusion imaging, as supported by the apparent improvement in signal integrity and spatial alignment, as well as improved SNR in the neck region. Compared with the 3D shim technique, the iShim technique showed improved conspicuous lesion findings in the neck region.
    No preview · Article · Dec 2015 · Investigative Radiology
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    ABSTRACT: Objective: The aim of this study was to assess the safety profile of ferumoxytol as an intravenous magnetic resonance imaging contrast agent in children. Materials and methods: We prospectively evaluated the safety of ferumoxytol administrations as an "off-label" contrast agent for magnetic resonance imaging in nonrandomized phase 4 clinical trials at 2 centers. From September 2009 to February 2015, 49 pediatric patients (21 female and 28 male, 5-18 years) and 19 young adults (8 female and 11 male, 18-25 years) were reported under an investigator-initiated investigational new drug investigation with institutional review board approval, in health insurance portability and accountability act compliance, and after written informed consent of the child's legal representative or the competent adult patient was obtained. Patients received either a single dose (5 mg Fe/kg) or up to 4 doses of ferumoxytol (0.7-4 mg Fe/kg) intravenously, which were approximately equivalent to one third of the dose for anemia treatment. We monitored vital signs and adverse events directly for up to 1 hour after injection. In addition, we examined weekly vitals, hematologic, renal, and liver serum panels for 1 month after injection in over 20 pediatric patients. At fixed time points before and after ferumoxytol injection, data were evaluated for significant differences by a repeated measures linear mixed model. Results: Four mild adverse events, thought to be related to ferumoxytol, were observed within 1 hour of 85 ferumoxytol injections: 2 episodes of mild hypotension and 1 case of nausea in 65 injections in pediatric patients without related clinical symptoms. One young adult patient developed warmness and erythema at the injection site. All adverse events were self-resolving. No spontaneous serious adverse events were reported. At a dose of 5 mg Fe/kg or lower, intravenous ferumoxytol injection had no clinical relevance or statistically significant effect (P > 0.05) on vital signs, hematological parameters, kidney function, or liver enzymes within 1 month of the injection. Conclusions: Ferumoxytol was overall well tolerated among 49 pediatric and 19 young adult patients experiencing various tumors or kidney transplants without major adverse events or signs of hematologic and kidney impairment or liver toxicity. Larger studies are needed to determine the incidence of anaphylactic reactions.
    No preview · Article · Dec 2015 · Investigative Radiology
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    ABSTRACT: Objective: The aim of this study was to assess the effect of temporal resolution on semiquantitative and pharmacokinetic parameters from dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) and their diagnostic accuracy regarding the detection of potentially malignant prostate lesions. Materials and methods: Sixty consecutive male patients (age, 64.5 ± 7.0 years) with clinically suspected prostate cancer were included. All patients underwent multiparametric MRI of the prostate (T2-weighted, diffusion-weighted imaging, and DCE-MRI) on a 3 T MRI scanner. Patients were divided into 2 groups depending on Prostate Imaging Reporting and Data System (PI-RADS) score of the detected lesions (group A: PI-RADS score ≤3, n = 30; group B: PI-RADS score >3, n = 30). In all patients, DCE-MRI was performed using a CAIPIRINHA-Dixon-TWIST Volume-Interpolated Breath-Hold Examination sequence (spatial resolution, 3 × 1.2 × 1.2 mm; temporal resolution, 5 seconds; total sampling duration, 4:10 minutes [250 seconds]) with body weight-adapted administration of contrast agent (gadobutrol, Gadovist; Bayer Healthcare, Berlin, Germany). Six DCE-MRI series with different temporal resolutions ranging from 5 to 30 seconds per time point were retrospectively generated from the original data sets. Semiquantitative parameters (ie, wash-in, wash-out, and time-to-peak [TTP]) as well as pharmacokinetic parameters (ie, Ktrans, Kep, and ve) were calculated for the different temporal resolutions. Both lesion groups and all 6 DCE-MRI series were compared regarding semiquantitative and pharmacokinetic parameters. Diagnostic accuracy for the detection of potentially malignant lesions was calculated for all 6 series using ROC analysis. Results: A significant effect of temporal resolution was found on wash-in (P < 0.001). Series with temporal resolution lower than 10 s/time point showed significantly lower wash-in values with more pronounced effects in group B compared with group A. For 30-second series, the differences between both groups diminished reaching insignificant levels (P = 0.052), resulting in a significant decrease of the diagnostic accuracy of wash-in (area under the curve, 0.609; 95% confidence interval, 0.451-0.766; P < 0.015). No significant effects were detected on wash-out. For TTP, a significant effect of temporal resolution was detected (P < 0.001) with significantly increasing TTP levels for all down-sampled series compared with the original 5-second series. These effects did not impact the diagnostic accuracy of TTP. No significant effects of temporal resolution were detected on pharmacokinetic parameters (P < 0.112). Conclusions: In DCE-MRI of the prostate, temporal resolution affects the diagnostic performance of semiquantitative parameters. For a sufficient detection of malignant prostate lesions on DCE-MRI, a temporal resolution of at least 10 s/time point or higher is recommended.
    No preview · Article · Nov 2015 · Investigative Radiology
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    ABSTRACT: Objective: The aim of this study was to assess the diagnostic value of whole-body low-dose (LD) computed tomography (CT) for the detection of ventriculoperitoneal (VP) shunt complications in pediatric patients compared with radiographic shunt series (SS) in an ex vivo rabbit animal model. Methods: In the first step, 2 optimized LD-CT imaging protocols, with high pitch (pitch, 3.2), low tube voltages (70 kVp and 80 kVp), and using both filtered back projection and iterative reconstruction, were assessed on a 16-cm solid polymethylmethacrylate phantom regarding signal-to-noise ratio and radiation dose. Taking both radiation dose and signal-to-noise ratio into account, the LD-CT protocol (80 kVp; 4 mA; pitch, 3.2) was identified as most appropriate and therefore applied in this study. After identification of appropriate LD-CT protocol, 12 VP shunts were implanted in 6 rabbit cadavers (mean weight, 5.1 kg). Twenty-four mechanical complications (extracranial and extraperitoneal malpositioning, breakages, and disconnections) were induced in half of the VP shunts. Low-dose CT and conventional SS were acquired in standard fashion. Dose-area products (DAPs) for SS and LD-CT were collected; effective radiation doses for both SS and LD-CT were estimated using CT-Expo (v. 2.3.1.) and age-specific effective dose (ED) estimates. Qualitative scoring of diagnostic confidence on a 5-point Likert scale (1, very low diagnostic confidence; 5, excellent diagnostic confidence) and blinded readings of both SS and LD-CTs were performed. Results: Among the 24 VP shunt complications, LD-CT yielded excellent sensitivity and specificity for the detection of VP shunt complications (sensitivity, 0.98; specificity, 1; 95% confidence interval, 0.92-1) with excellent interobserver agreement ([kappa] = 0.90). Shunt series yielded good sensitivity and specificity (sensitivity, 0.75; specificity, 1; 95% confidence interval, 0.58-0.92) with moderate interobserver agreement ([kappa] = 0.56). No false-positive findings were registered. Compared with SS, LD-CT yielded significantly lower ED and DAPs (ED, 0.039 vs 0.062 mSv; DAP, 20.5 vs 26.3; P < 0.05). Conclusions: In this experimental ex vivo pediatric patient model, LD-CT yields excellent sensitivity for the detection of VP shunt complications at higher diagnostic confidence and lower radiation exposure compared with SS.
    No preview · Article · Aug 2015 · Investigative Radiology

  • No preview · Article · Aug 2015 · Investigative Radiology
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    ABSTRACT: Our study aim was to assess the radiation dose of digital breast tomosynthesis (DBT) in comparison to full-field digital mammography (FFDM) in a clinical setting. Two-hundred four patients were consecutively included, of which 236 complementary DBT and FFDM examinations were available. All acquisitions were performed on a single commercially available mammography system capable of FFDM and DBT acquisitions using an antiscatter grid. The average glandular dose (AGD) was calculated for each examination using the Dance method. For this, tube output and half-value layer were measured, and the required exposure parameters (target/filter material, tube voltage, tube load, compressed breast thickness) were retrieved from the DICOM metadata. The DBT and FFDM AGD values were pairwise tested, and a subanalysis with respect to breast thickness was performed. The mean (SD) AGD values for a single-view DBT and FFDM were 1.49 (0.36) mGy and 1.62 (0.55) mGy, respectively, which are small but statistically significant differences. This difference may be partially attributed to the small difference in the mean breast thickness between FFDM and DBT (3 mm). In this patient population, the AGD was lower for DBT than for FFDM in 61% of the patients. When patients were categorized according to breast thickness, the AGD of DBT was only significantly smaller than the AGD of FFDM for breast thickness categories larger than 50 mm, indicating that the dose reduction for DBT compared with FFDM was more pronounced in thick breasts. The radiation dose of patients undergoing a single-view DBT was comparable to a single-view FFDM. For patients with thicker breasts, the radiation dose of DBT was slightly lower than FFDM.
    No preview · Article · May 2015 · Investigative Radiology

  • No preview · Article · May 2015 · Investigative Radiology
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    ABSTRACT: Objectives: The objective of this study was to evaluate the radiation dose and image quality performance of thoracoabdominal examinations with an automated tube voltage selection (tube voltage adaptation), tube current modulation, and high pitch using a third-generation dual-source computed tomography (CT) compared intraindividually with 120-kV examinations with tube current modulation with special attention on clinically relevant lesions in the liver, the lungs, and extrahepatic soft tissues. Materials and Methods: This study was approved by the institutional review board. Computed tomography of the body was performed using a third-generation dual-source systemin 95 patients (mean body mass index, 25 kg/m(2); range, 18-35 kg/m(2)). For 49 of these patients, all calculated tube settings and resulting dose values were recorded for each of the 12 gradual contrast weightings of the tube voltage adaptation algorithm. Spiral CTwas performed for all patients with an intermediate weighting (grade 7) in a portal venous phase at 120 reference kV, 180 reference mAs, and pitch of 1.55. Objective image quality was assessed on the basis of contrast-to-noise ratio. Subjective image quality was assessed on the basis of clarity and sharpness of anatomical and pathological structures aswell as interfering beam hardening and spiral and motion artifacts (heart, lungs, diaphragm). Previous examinations on a 64-slice scanner served as reference. Results: All examinationswere rated good or excellent for clinical diagnosis. Automated tube voltage selection resulted in significantly lower effective radiation dose (9.5 mSv) compared with the reference (12.0 mSv; P < 0.01). Contrast-to-noise ratio and image quality of soft tissue lesions were significantly increased (P < 0.01). Motion artifacts were significantly reduced (P < 0.01). Conclusions: Automated tube voltage adaptation combined with high-pitch protocols allows for a substantial radiation dose reduction while substantially increasing the image quality, even at large-volume exposure.
    No preview · Article · May 2015 · Investigative Radiology
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    ABSTRACT: Objectives: The purpose of this study was to explore the potential of non-Gaussian diffusion and perfusion magnetic resonance imaging (MRI) using intravoxel incoherent motion (IVIM) MRI for the diagnosis of breast lesions. Materials and Methods: This study included 26 women with breast lesions. Diffusion-weighted images were acquired using 16 b values up to 2500 s/mm(2) and analyzed using a kurtosis diffusion model (apparent diffusion coefficient [ADC(0)] and kurtosis [K]) for the diffusion component and IVIM model (perfusion fraction [fIVIM] and pseudodiffusion coefficient [D*]) for the perfusion component. Diagnostic performance of diffusion and perfusion parameters was evaluated from receiver operating characteristic analyses. Results: The ADC(0) in malignant lesions was significantly lower than that in benign lesions and normal tissue (P < 0.001, P < 0.001), whereas K was significantly higher (P < 0.05, P < 0.001), as well as fIVIM (P < 0.05, P < 0.01). No significant difference was found in D*. The receiver operating characteristic analysis gave high area under the curve values for ADC(0), K, and fIVIM for distinguishing malignant from benign lesions (0.99, 0.85, and 0.82, respectively). The ADC(0) allowed benign tumors to be identified with 100% negative predictive value and malignant tumors with 100% sensitivity. The malignant/benign diagnosis thresholds were 1.4 +/- 10(-3) mm(2)/s as well as 0.6 and 7%, respectively, for ADC(0), K, and fIVIM. Conclusions: With a proper methodological framework, IVIM MRI can provide valuable information on tissue structure and microvasculature beneficial for the diagnosis of breast cancer lesions.
    No preview · Article · Apr 2015 · Investigative Radiology