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Ohno Y, Ozawa Y, Nagata H, Ueda T, Yoshikawa T, Takenaka D, Koyama H. Lung Magnetic Resonance Imaging: Technical Advancements and Clinical Applications. Invest Radiol 2024; 59:38-52. [PMID: 37707840 DOI: 10.1097/rli.0000000000001017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
ABSTRACT Since lung magnetic resonance imaging (MRI) became clinically available, limited clinical utility has been suggested for applying MRI to lung diseases. Moreover, clinical applications of MRI for patients with lung diseases or thoracic oncology may vary from country to country due to clinical indications, type of health insurance, or number of MR units available. Because of this situation, members of the Fleischner Society and of the Japanese Society for Magnetic Resonance in Medicine have published new reports to provide appropriate clinical indications for lung MRI. This review article presents a brief history of lung MRI in terms of its technical aspects and major clinical indications, such as (1) what is currently available, (2) what is promising but requires further validation or evaluation, and (3) which developments warrant research-based evaluations in preclinical or patient studies. We hope this article will provide Investigative Radiology readers with further knowledge of the current status of lung MRI and will assist them with the application of appropriate protocols in routine clinical practice.
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Affiliation(s)
- Yoshiharu Ohno
- From the Department of Diagnostic Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y. Ohno); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y. Ohno and H.N.); Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y. Ozawa and T.U.); Department of Diagnostic Radiology, Hyogo Cancer Center, Akashi, Hyogo, Japan (T.Y., D.T.); and Department of Radiology, Advanced Diagnostic Medical Imaging, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (H.K.)
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Tsuchiya N, Beek EJRV, Ohno Y, Hatabu H, Kauczor HU, Swift A, Vogel-Claussen J, Biederer J, Wild J, Wielpütz MO, Schiebler ML. Magnetic resonance angiography for the primary diagnosis of pulmonary embolism: A review from the international workshop for pulmonary functional imaging. World J Radiol 2018; 10:52-64. [PMID: 29988845 PMCID: PMC6033703 DOI: 10.4329/wjr.v10.i6.52] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Revised: 04/25/2018] [Accepted: 05/30/2018] [Indexed: 02/06/2023] Open
Abstract
Pulmonary contrast enhanced magnetic resonance angiography (CE-MRA) is useful for the primary diagnosis of pulmonary embolism (PE). Many sites have chosen not to use CE-MRA as a first line of diagnostic tool for PE because of the speed and higher efficacy of computerized tomographic angiography (CTA). In this review, we discuss the strengths and weaknesses of CE-MRA and the appropriate imaging scenarios for the primary diagnosis of PE derived from our unique multi-institutional experience in this area. The optimal patient for this test has a low to intermediate suspicion for PE based on clinical decision rules. Patients in extremis are not candidates for this test. Younger women (< 35 years of age) and patients with iodinated contrast allergies are best served by using this modality We discuss the history of the use of this test, recent technical innovations, artifacts, direct and indirect findings for PE, ancillary findings, and the effectiveness (patient outcomes) of CE-MRA for the exclusion of PE. Current outcomes data shows that CE-MRA and NM V/Q scans are effective alternative tests to CTA for the primary diagnosis of PE.
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Affiliation(s)
- Nanae Tsuchiya
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Okinawa 903-0215, Japan
- Department of Radiology, University of Wisconsin-Madison, Madison, WI 53792, United States
| | - Edwin JR van Beek
- Edinburgh Imaging, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, United Kingdom
| | - Yoshiharu Ohno
- Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Hiroto Hatabu
- Department of Radiology, Brigham and Women’s Hospital, Boston, MA 02115, United States
| | - Hans-Ulrich Kauczor
- Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg 69120, Germany
| | - Andrew Swift
- Department of Radiology, Royal Hallamshire Hospital, University of Sheffield, Sheffield S10 2JF, United Kingdom
| | - Jens Vogel-Claussen
- Department of Radiology, Carl-Neuberg Strasse 1, Hannover-Gr-Buchholz 30625, Germany
| | - Jürgen Biederer
- Radiology Darmstadt, Gross-Gerau County Hospital, Gross-Gerau 64521, Germany
| | - James Wild
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2JF, United Kingdom
| | - Mark O Wielpütz
- Department of Diagnostic and Interventional Radiology, University Hospital of Heidelberg, Heidelberg 69120, Germany
| | - Mark L Schiebler
- Department of Radiology, University of Wisconsin-Madison, Madison, WI 53792, United States
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Repplinger MD, Nagle SK, Harringa JB, Broman AT, Lindholm CR, François CJ, Grist TM, Reeder SB, Schiebler ML. Clinical outcomes after magnetic resonance angiography (MRA) versus computed tomographic angiography (CTA) for pulmonary embolism evaluation. Emerg Radiol 2018; 25:469-477. [PMID: 29749576 DOI: 10.1007/s10140-018-1609-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 04/25/2018] [Indexed: 12/17/2022]
Abstract
PURPOSE To compare patient outcomes following magnetic resonance angiography (MRA) versus computed tomographic angiography (CTA) ordered for suspected pulmonary embolism (PE). METHODS In this IRB-approved, single-center, retrospective, case-control study, we reviewed the medical records of all patients evaluated for PE with MRA during a 5-year period along with age- and sex-matched controls evaluated with CTA. Only the first instance of PE evaluation during the study period was included. After application of our exclusion criteria to both study arms, the analysis included 1173 subjects. The primary endpoint was major adverse PE-related event (MAPE), which we defined as major bleeding, venous thromboembolism, or death during the 6 months following the index imaging test (MRA or CTA), obtained through medical record review. Logistic regression, chi-square test for independence, and Fisher's exact test were used with a p < 0.05 threshold. RESULTS The overall 6-month MAPE rate following MRA (5.4%) was lower than following CTA (13.6%, p < 0.01). Amongst outpatients, the MAPE rate was lower for MRA (3.7%) than for CTA (8.0%, p = 0.01). Accounting for age, sex, referral source, BMI, and Wells' score, patients were less likely to suffer MAPE than those who underwent CTA, with an odds ratio of 0.44 [0.24, 0.80]. Technical success rate did not differ significantly between MRA (92.6%) and CTA (90.5%) groups (p = 0.41). CONCLUSION Within the inherent limitations of a retrospective case-controlled analysis, we observed that the rate of MAPE was lower (more favorable) for patients following pulmonary MRA for the primary evaluation of suspected PE than following CTA.
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Affiliation(s)
- Michael D Repplinger
- BerbeeWalsh Department of Emergency Medicine, University of Wisconsin, 800 University Bay Drive, Suite 310, Mail Code 9123, Madison, WI, 53705, USA. .,Department of Radiology, University of Wisconsin, Madison, WI, USA.
| | - Scott K Nagle
- Department of Radiology, University of Wisconsin, Madison, WI, USA.,Department of Medical Physics, University of Wisconsin, Madison, WI, USA.,Department of Pediatrics, University of Wisconsin, Madison, WI, USA
| | - John B Harringa
- BerbeeWalsh Department of Emergency Medicine, University of Wisconsin, 800 University Bay Drive, Suite 310, Mail Code 9123, Madison, WI, 53705, USA.,School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Aimee T Broman
- Department of Biostatistics, University of Wisconsin, Madison, WI, USA
| | - Christopher R Lindholm
- Department of Medicine, Dartmouth University, Geisel School of Medicine, Hanover, NH, USA
| | - Christopher J François
- BerbeeWalsh Department of Emergency Medicine, University of Wisconsin, 800 University Bay Drive, Suite 310, Mail Code 9123, Madison, WI, 53705, USA.,Department of Medicine, University of Wisconsin, Madison, WI, USA
| | - Thomas M Grist
- Department of Radiology, University of Wisconsin, Madison, WI, USA.,Department of Medical Physics, University of Wisconsin, Madison, WI, USA.,Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Scott B Reeder
- BerbeeWalsh Department of Emergency Medicine, University of Wisconsin, 800 University Bay Drive, Suite 310, Mail Code 9123, Madison, WI, 53705, USA.,Department of Radiology, University of Wisconsin, Madison, WI, USA.,Department of Medical Physics, University of Wisconsin, Madison, WI, USA.,Department of Pediatrics, University of Wisconsin, Madison, WI, USA.,Department of Medicine, University of Wisconsin, Madison, WI, USA.,Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
| | - Mark L Schiebler
- Department of Radiology, University of Wisconsin, Madison, WI, USA
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Sista AK, Kuo WT, Schiebler M, Madoff DC. Stratification, Imaging, and Management of Acute Massive and Submassive Pulmonary Embolism. Radiology 2017. [DOI: 10.1148/radiol.2017151978] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Akhilesh K. Sista
- From the Dept of Radiology, Div of Interventional Radiology, Weill Cornell Medical College, 525 E 68th St, New York, NY 10065 (A.K.S., D.C.M.); Dept of Radiology, Div of Interventional Radiology, Stanford Univ School of Medicine, Stanford, Calif (W.T.K.); and Dept of Radiology, Univ of Wisconsin School of Medicine, Madison, Wis (M.S.)
| | - William T. Kuo
- From the Dept of Radiology, Div of Interventional Radiology, Weill Cornell Medical College, 525 E 68th St, New York, NY 10065 (A.K.S., D.C.M.); Dept of Radiology, Div of Interventional Radiology, Stanford Univ School of Medicine, Stanford, Calif (W.T.K.); and Dept of Radiology, Univ of Wisconsin School of Medicine, Madison, Wis (M.S.)
| | - Mark Schiebler
- From the Dept of Radiology, Div of Interventional Radiology, Weill Cornell Medical College, 525 E 68th St, New York, NY 10065 (A.K.S., D.C.M.); Dept of Radiology, Div of Interventional Radiology, Stanford Univ School of Medicine, Stanford, Calif (W.T.K.); and Dept of Radiology, Univ of Wisconsin School of Medicine, Madison, Wis (M.S.)
| | - David C. Madoff
- From the Dept of Radiology, Div of Interventional Radiology, Weill Cornell Medical College, 525 E 68th St, New York, NY 10065 (A.K.S., D.C.M.); Dept of Radiology, Div of Interventional Radiology, Stanford Univ School of Medicine, Stanford, Calif (W.T.K.); and Dept of Radiology, Univ of Wisconsin School of Medicine, Madison, Wis (M.S.)
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5
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Benson DG, Schiebler ML, Repplinger MD, François CJ, Grist TM, Reeder SB, Nagle SK. Contrast-enhanced pulmonary MRA for the primary diagnosis of pulmonary embolism: current state of the art and future directions. Br J Radiol 2017; 90:20160901. [PMID: 28306332 DOI: 10.1259/bjr.20160901] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
CT pulmonary angiography (CTPA) is currently considered the imaging standard of care for the diagnosis of pulmonary embolism (PE). Recent advances in contrast-enhanced pulmonary MR angiography (MRA) techniques have led to increased use of this modality for the detection of PE in the proper clinical setting. This review is intended to provide an introduction to the state-of-the-art techniques used in pulmonary MRA for the detection of PE and to discuss possible future directions for this modality. This review discusses the following issues pertinent to MRA for the diagnosis of PE: (1) the diagnostic efficacy and clinical effectiveness for pulmonary MRA relative to CTPA, (2) the different pulmonary MRA techniques used for the detection of PE, (3) guidance for building a clinical service at their institution using MRA and (4) future directions of PE MRA. Our principal aim was to show how pulmonary MRA can be used as a safe, effective modality for the diagnosis of clinically significant PE, particularly for those patients where there are concerns about ionizing radiation or contraindications/allergies to the iodinated contrast material.
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Affiliation(s)
- Donald G Benson
- 1 Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Mark L Schiebler
- 1 Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael D Repplinger
- 1 Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA.,2 Department of Emergency Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | | | - Thomas M Grist
- 1 Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA.,3 Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.,4 Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Scott B Reeder
- 1 Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA.,2 Department of Emergency Medicine, University of Wisconsin-Madison, Madison, WI, USA.,3 Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.,4 Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, USA.,5 Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Scott K Nagle
- 1 Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA.,3 Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.,6 Department of Pediatrics, University of Wisconsin-Madison, Madison, WI, USA
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Incidence of actionable findings on contrast enhanced magnetic resonance angiography ordered for pulmonary embolism evaluation. Eur J Radiol 2016; 85:1383-9. [PMID: 27423676 DOI: 10.1016/j.ejrad.2016.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/27/2016] [Accepted: 05/19/2016] [Indexed: 12/31/2022]
Abstract
PURPOSE To determine the incidence of actionable findings on contrast-enhanced magnetic resonance angiography (MRA) scans performed for the primary diagnosis of pulmonary embolism (PE). MATERIALS AND METHODS This was a HIPAA-compliant and IRB-approved single center, retrospective study of consecutive series of patients evaluated with contrast-enhanced MRA for PE. The final radiology report of each MRA was reviewed. All technically adequate negative exams were included in the analysis. The findings were divided into three types: those requiring further action (actionable-Type 1) those not requiring follow-up (non-actionable-Type 2) and normal exams. We compared our results with the literature regarding the use of computed tomographic angiography (CTA) in this scenario using Fisher's exact test. RESULTS 580 MRA scans for PE were performed. There were 561/580 (97%) technically adequate exams. Of these, 514/580 (89%) were negative and 47/580 (8%) were positive for PE. In the PE negative group of 514 exams, Type 1 findings were identified in 85/514 (17%), 188/514 (36%) cases were Type 2 and 241/514 (47.0%) were Type 3. There was no significant difference between the incidence of Type 1 and the combination of Type 2 and Type 3 findings on MRA and the reported incidence of actionable findings derived from CTA negative exams for PE (p<0.5). CONCLUSION MRA as a first-line test for PE can identify actionable findings in those patients without PE, with an incidence similar to that reported in the literature for CTA.
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Ohno Y, Koyama H, Yoshikawa T, Seki S, Takenaka D, Yui M, Lu A, Miyazaki M, Sugimura K. Pulmonary high-resolution ultrashort TE MR imaging: Comparison with thin-section standard- and low-dose computed tomography for the assessment of pulmonary parenchyma diseases. J Magn Reson Imaging 2015. [PMID: 26223818 DOI: 10.1002/jmri.25008] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND To determine the accuracy of pulmonary MR imaging with ultrashort echo time (UTE) for lung and mediastinum assessments using computed tomography (CT) as the reference standard, for various pulmonary parenchyma diseases. METHODS Eight-five consecutive patients (46 males: mean age, 69 years and 39 females: mean age, 69 years) with various pulmonary parenchyma diseases were examined with chest standard- and low-dose CTs and pulmonary MR imaging with UTE. This was followed by visual assessment using a 5-point system of the presence of nodules or masses, ground-glass opacity, micronodules, nodules, patchy shadow or consolidation, emphysema or bullae, bronchiectasis, reticular opacity, and honeycomb and traction bronchiectasis. Presence of aneurysms, pleural or pericardial effusions, pleural thickening or tumor, and lymph adenopathy was also evaluated using a 5-point system. To compare the capability of the methods for lung parenchyma and mediastinum evaluation, intermethod agreement was evaluated by means of kappa statistics and χ2 test. Receiver operating characteristic analyses were used to compare diagnostic performance of all methods. RESULTS Intermethod agreements between pulmonary MR imaging and standard-dose and low-dose CT were significant and either substantial or almost perfect (0.67 ≤ κ ≤ 0.98; P < 0.0001). Areas under the curve for emphysema or bullae, bronchiectasis or traction bronchiectasis and reticular opacity on standard-dose CT were significantly larger than those on low-dose CT (emphysema or bullae: P = 0.0002; reticular opacity: P < 0.0001) and pulmonary MR imaging (emphysema or bullae: P < 0.0001; bronchiectasis: P = 0.008; reticular opacity: P < 0.0001). CONCLUSION Pulmonary MR imaging with UTE is useful for lung and mediastinum assessment and evaluation of radiological findings for patients with various pulmonary parenchyma diseases.
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Affiliation(s)
- Yoshiharu Ohno
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Hisanobu Koyama
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Takeshi Yoshikawa
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan.,Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Shinichiro Seki
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Daisuke Takenaka
- Department of Radiology, Hyogo Cancer Center, Akashi, Hyogo, Japan
| | - Masao Yui
- Toshiba Medical Systems Corporation, Otawara, Tochigi, Japan
| | - Aiming Lu
- Toshiba Medical Research Institute USA, Vernon Hills, Illinois, USA
| | - Mitsue Miyazaki
- Toshiba Medical Research Institute USA, Vernon Hills, Illinois, USA
| | - Kazuro Sugimura
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
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Levin D, Seo JB, Kiely DG, Hatabu H, Gefter W, van Beek EJR, Schiebler ML. Triage for suspected acute Pulmonary Embolism: Think before opening Pandora's Box. Eur J Radiol 2015; 84:1202-11. [PMID: 25864020 DOI: 10.1016/j.ejrad.2015.03.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Revised: 02/26/2015] [Accepted: 03/23/2015] [Indexed: 12/22/2022]
Abstract
This is a review of the current strengths and weaknesses of the various imaging modalities available for the diagnosis of suspected non-massive Pulmonary Embolism (PE). Without careful consideration for the clinical presentation, and the timely application of clinical decision support (CDS) methodology, the current overutilization of imaging resources for this disease will continue. For a patient with a low clinical risk profile and a negative D-dimer there is no reason to consider further workup with imaging; as the negative predictive value in this scenario is the same as imaging. While the current efficacy and effectiveness data support the continued use of Computed Tomographic angiography (CTA) as the imaging golden standard for the diagnosis of PE; this test does have the unintended consequences of radiation exposure, possible overdiagnosis and overuse. There is a persistent lack of appreciation on the part of ordering physicians for the effectiveness of the alternatives to CTA (ventilation-perfusion imaging and contrast enhanced magnetic resonance angiography) in these patients. Careful use of standardized protocols for patient triage and the application of CDS will allow for a better use of imaging resources.
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Affiliation(s)
- David Levin
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Joon Beom Seo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - David G Kiely
- Sheffield Pulmonary Vascular Disease Unit, M-15, M-Floor, Royal Hallamshire Hospital, Sheffield, UK
| | - Hiroto Hatabu
- Department of Radiology, Brigham and Women's Hospital and Harvard Medical School Boston, MA, USA
| | - Warren Gefter
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
| | | | - Mark L Schiebler
- Department of Radiology, UW-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, WI 53792-3252, USA.
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9
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Schiebler ML, Nagle SK, François CJ, Repplinger MD, Hamedani AG, Vigen KK, Yarlagadda R, Grist TM, Reeder SB. Effectiveness of MR angiography for the primary diagnosis of acute pulmonary embolism: clinical outcomes at 3 months and 1 year. J Magn Reson Imaging 2013; 38:914-25. [PMID: 23553735 PMCID: PMC3970266 DOI: 10.1002/jmri.24057] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Accepted: 01/07/2013] [Indexed: 12/22/2022] Open
Abstract
PURPOSE To determine the effectiveness of MR angiography for pulmonary embolism (MRA-PE) in symptomatic patients. MATERIALS AND METHODS We retrospectively reviewed all patients whom were evaluated for possible pulmonary embolism (PE) using MRA-PE. A 3-month and 1-year from MRA-PE electronic medical record (EMR) review was performed. Evidence for venous thromboembolism (VTE) (or death from PE) within the year of follow-up was the outcome surrogate for this study. RESULTS There were 190 MRA-PE exams performed with 97.4% (185/190) of diagnostic quality. There were 148 patients (120 F: 28 M) that had both a diagnostic MRA-PE exam and 1 complete year of EMR follow-up. There were 167 patients (137 F: 30 M) with 3 months or greater follow-up. We found 83% (139/167) and 81% (120/148) MRA-PE exams negative for PE at 3 months and 1 year, respectively. Positive exams for PE were seen in 14% (23/167). During the 1-year follow-up period, five patients (false negative) were diagnosed with DVT (5/148 = 3.4 %), and one of these patients also experienced a non-life-threatening PE. The negative predictive value (NPV) for MRA-PE was 97% (92-99; 95% CI) at 3 months and 96% (90-98; 95% CI) with 1 year of follow-up. CONCLUSION The NPV of MRA-PE, when used for the primary diagnosis of pulmonary embolism in symptomatic patients, were found to be similar to the published values for CTA-PE. In addition, the technical success rate and safety of MRA-PE were excellent.
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Affiliation(s)
- Mark L. Schiebler
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Scott K. Nagle
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
- Department of Pediatrics, University of Wisconsin, Madison, Wisconsin, USA
| | - Christopher J. François
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | | | - Azita G. Hamedani
- Department of Emergency Medicine, Uinveristy of Wisconsin, Madison, WI, USA
| | - Karl K. Vigen
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Rajkumar Yarlagadda
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Omaha Imaging, Omaha, Nebraska, USA
| | - Thomas M. Grist
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
- Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA
| | - Scott B. Reeder
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
- Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA
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10
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Londy FJ, Lowe S, Stein PD, Weg JG, Eisner RL, Leeper KV, Woodard PK, Sostman HD, Jablonski KA, Fowler SE, Hales CA, Hull RD, Gottschalk A, Naidich DP, Chenevert TL. Comparison of 1.5 and 3.0 T for contrast-enhanced pulmonary magnetic resonance angiography. Clin Appl Thromb Hemost 2011; 18:134-9. [PMID: 21993980 DOI: 10.1177/1076029611419840] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE In a recent multi-center trial of gadolinium contrast-enhanced magnetic resonance angiography (Gd-MRA) for diagnosis of acute pulmonary embolism (PE), two centers utilized a common MRI platform though at different field strengths (1.5T and 3T) and realized a signal-to-noise gain with the 3T platform. This retrospective analysis investigates this gain in signal-to-noise of pulmonary vascular targets. METHODS Thirty consecutive pulmonary MRA examinations acquired on a 1.5T system at one institution were compared to 30 consecutive pulmonary MRA examinations acquired on a 3T system at a different institution. Both systems were from the same MRI manufacturer and both used the same Gd-MRA pulse sequence, although there were some protocol adjustments made due to field strength differences. Region-of-interests were manually defined on the main pulmonary artery, 4 pulmonary veins, thoracic aorta, and background lung for objective measurement of signal-to-noise, contrast-to-noise, and bolus timing bias between centers. RESULTS The 3T pulmonary MRA protocol achieved higher spatial resolution yet maintained significantly higher signal-to-noise ratio (≥13%, p = 0.03) in the main pulmonary vessels relative to 1.5T. There was no evidence of operator bias in bolus timing or patient hemodynamic differences between groups. CONCLUSION Relative to 1.5T, higher spatial resolution Gd-MRA can be achieved at 3T with a sustained or greater signal-to-noise ratio of enhanced vasculature.
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11
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Okajima Y, Ohno Y, Washko GR, Hatabu H. Assessment of pulmonary hypertension what CT and MRI can provide. Acad Radiol 2011; 18:437-53. [PMID: 21377593 DOI: 10.1016/j.acra.2011.01.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/06/2011] [Accepted: 01/12/2011] [Indexed: 01/06/2023]
Abstract
RATIONALES AND OBJECTIVES Pulmonary hypertension (PH) is a life-threatening condition, characterized by elevated pulmonary arterial pressure, which is confirmed based on invasive right heart catheterization (RHC). Noninvasive examinations may support diagnosis of PH before proceeding to RHC and play an important role in management and treatment of the disease. Although echocardiography is considered a standard tool in diagnosis, recent advances have made computed tomography (CT) and magnetic resonance (MR) imaging promising tools, which may provide morphologic and functional information. In this article, we review image-based assessment of PH with a focus on CT and MR imaging. CONCLUSIONS CT may provide useful morphologic information for depicting PH and seeking for underlying diseases. With the accumulated technological advancement, CT and MRI may provide practical tools for not only morphologic but also functional assessment of patients with PH.
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Affiliation(s)
- Yuka Okajima
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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12
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Challenges in the diagnosis of acute pulmonary embolism. Am J Med 2008; 121:565-71. [PMID: 18589050 DOI: 10.1016/j.amjmed.2008.02.033] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Revised: 02/05/2008] [Accepted: 02/08/2008] [Indexed: 11/22/2022]
Abstract
The state of the art of diagnostic evaluation of hemodynamically stable patients with suspected acute pulmonary embolism was reviewed. Diagnostic evaluation should begin with clinical assessment using a validated prediction rule in combination with measurement of D-dimer when appropriate. Imaging should follow only when necessary. Although with 4-slice computed tomography (CT) and 16-slice CT, the sensitivity for detection of pulmonary embolism was increased by combining CT angiography with CT venography, it is not known whether CT venography increases the sensitivity of 64-slice CT angiography. Methods to reduce the radiation exposure of CT venography include imaging only the proximal leg veins (excluding the pelvis) and obtaining discontinuous images. Compression ultrasound can be used instead. In young women, radiation of the breasts produces the greatest risk of radiation-induced cancer. It may be that scintigraphy is the imaging test of choice in such patients, but this pathway should be tested prospectively. A patient-specific approach to the diagnosis of pulmonary embolism can be taken safely in hemodynamically stable patients to increase efficiency and decrease cost and exposure to radiation.
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Venous Disease and Pulmonary Embolism. Surgery 2008. [DOI: 10.1007/978-0-387-68113-9_68] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
Pulmonary embolism (PE) is a common problem. Given the significant overlap of symptoms and signs between the presentation of PE and acute coronary syndromes, it becomes clear that cardiologists must be familiar with the diagnosis and treatment of PE. The critical issue is always to consider PE in the diagnosis of chest pain. It is then important to determine the likelihood of the diagnosis. For patients at moderate-to-high risk, helical CT provides a rapid and noninvasive diagnostic tool. Several other imaging studies are also available including ventilation/perfusion (V/Q) scan, magnetic resonance imaging, and pulmonary arteriography. Echocardiography can also provide valuable prognostic information. Several biomarkers including the d-dimers, troponins, and natriuretic peptides may provide additional information. The cornerstone of treatment includes anticoagulation. For patients with massive or submassive PE, thrombolysis and embolectomy should be considered. Finally, both primary and secondary prevention are critical to the long-term health of the patient.
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Affiliation(s)
- Aly Rahimtoola
- Cardiovascular Division, The Oregon Clinic in Portland, USA
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15
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Dimitrov IE, Insko E, Rizi R, Leigh JS. Indirect detection of lung perfusion using susceptibility-based hyperpolarized gas imaging. J Magn Reson Imaging 2005; 21:149-55. [PMID: 15666407 DOI: 10.1002/jmri.20246] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To address the problem of inadequate signal-to-noise ratio (SNR) encountered in lung perfusion magnetic resonance imaging (MRI) by developing an indirect detection based on the strong hyperpolarized (HP) gas signal. MATERIALS AND METHODS Our model is based on detecting the effects of gadolinium (Gd) flowing through lung capillaries by recording the phase of the nearby alveolar HP gas. In a HP gas 3He phantom we imaged gas phases before and after removing tubes containing paramagnetic solution away from the phantom. We also imaged HP gas phases in pig lungs before and after injection of Gd. Finally, parenchymal spin phase in excised lungs was measured as a function of Gd concentration. RESULTS In the phantom, the differential phase map displayed a pattern characteristic of a susceptibility-induced dipole field, showing the possibility of an indirect detection. In vivo, the differential phase map showed homogeneous appearance, as expected for uniform perfusion in healthy lungs. Ex vivo, the parenchymal spin phases were shown to depend linearly on Gd concentration. CONCLUSION Our method should allow indirect perfusion (Q) and direct ventilation (V) to be assessed simultaneously, thus allowing for diagnosis of V/Q mismatches. The linear dependency of parenchymal spin phase vs. Gd concentration may allow for quantification of lung perfusion.
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Affiliation(s)
- Ivan E Dimitrov
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
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Stein PD, Woodard PK, Hull RD, Kayali F, Weg JG, Olson RE, Fowler SE. Gadolinium-enhanced magnetic resonance angiography for detection of acute pulmonary embolism: an in-depth review. Chest 2004; 124:2324-8. [PMID: 14665516 DOI: 10.1016/s0012-3692(15)31694-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
STUDY OBJECTIVE To review the published experience with gadolinium-enhanced magnetic resonance angiography (MRA) for the detection of acute pulmonary embolism (PE) in order to test the hypothesis that gadolinium-enhanced MRA may be potentially sensitive and specific enough to include it among diagnostic alternatives in the evaluation of patients with suspected PE. METHODS Studies were identified by searching MEDLINE for trials that used gadolinium-enhanced MRA to diagnose acute PE based on the visualization of an intraluminal filling defect or a cutoff vessel, using pulmonary angiography as a reference standard. RESULTS Twenty-eight investigations were identified in which MRA was used to diagnose PE. Only three studies, however, met the criteria for inclusion in the analysis. In these three case series, the sensitivity of gadolinium-enhanced MRA ranged from 77 to 100%, and the specificity ranged from 95 to 98%. CONCLUSION Gadolinium-enhanced MRA may be a useful diagnostic alternative in some patients with suspected acute PE, particularly if they have an elevated creatinine level, have an allergy to radiographic contrast material, or should, if possible, avoid exposure to ionizing radiation.
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Affiliation(s)
- Paul D Stein
- St. Joseph Mercy Oakland Hospital, 44555 Woodward Avenue, Suite 107, Pontiac, MI 48341-2985, USA.
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van Beek EJR, Wild JM, Fink C, Moody AR, Kauczor HU, Oudkerk M. MRI for the diagnosis of pulmonary embolism. J Magn Reson Imaging 2003; 18:627-40. [PMID: 14635147 DOI: 10.1002/jmri.10421] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Pulmonary embolism (PE) is one of the most frequently encountered clinical emergencies. The diagnosis often involves multiple diagnostic tests, which need to be carried out rapidly to assist in the safe management of the patient. Recent strides in computed tomography (CT) have made big improvements in patient management and efficiency of diagnostic imaging. This review article describes the developments in magnetic resonance (MR) techniques for the diagnosis of acute PE. Techniques include MR angiography (MRA) and thrombus imaging for direct clot visualization, perfusion MR, and combined perfusion-ventilation MR. As will be demonstrated, some of these techniques are now entering the clinical arena, and it is anticipated that MR imaging (MRI) will have an increasing role in the initial diagnosis and follow-up of patients with acute PE.
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Hatabu H, Uematsu H, Nguyen B, Miller WT, Hasegawa I, Gefter WB. CT and MR in pulmonary embolism: A changing role for nuclear medicine in diagnostic strategy. Semin Nucl Med 2002; 32:183-92. [PMID: 12105799 DOI: 10.1053/snuc.2002.125973] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The goal of this article is to summarize current data on computed tomography (CT) and magnetic resonance (MR) in the diagnosis of acute pulmonary embolism (PE) in relation to the radionuclide ventilation perfusion scan. It is important for the nuclear medicine, CT, and MR communities to develop a shared approach to this disorder. Triage using chest radiographs appears to be a practical method for enhancing both nuclear medicine and CT/MR performance. The realization that there is no clinically available gold standard for the diagnosis of PE suggests that the imaging community should replace impractical and idealistic discussions with more realistic outcome-oriented approaches. A simplified one-step evaluation of the pulmonary arteries and the lower extremity veins for deep venous thrombus can provide a comprehensive examination for PE. CT is currently a more practical diagnostic tool, whereas MR offers a scientific probe for pulmonary physiology including the regional mapping of ventilation-perfusion relationships. Nuclear medicine, CT, and MR thus form an imaging triad for the diagnosis of acute PE.
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Affiliation(s)
- Hiroto Hatabu
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA 19104, USA
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Abstract
This article describes the ultrasound guidelines for evaluating patients with spermatic cord torsion, including gray-scale, Doppler with spectral analysis, and color and power Doppler sonography. The sonographic and Doppler features of acute, subacute, and chronic torsion of the spermatic cord are demonstrated and discussed.
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Affiliation(s)
- Décio Prando
- Unidade Radiologica Paulista São Paulo, São Paulo, Brazil.
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Abstract
Despite the publication of the Prospective Investigation of Pulmonary Embolism Diagnosis in 1990, the diagnostic evaluation of pulmonary embolism continues to be approached in an inconsistent fashion. The reasons for this are unclear but likely have to do with inadequate methods for predicting pretest probability of disease and the inconvenience and perceived risk of pulmonary angiography. Because pulmonary embolism and its treatment carry substantial risk of morbidity and mortality, a consistent approach to evaluation is desirable. This article reviews large, prospective studies that suggest that it may be unnecessary to diagnose pulmonary embolism with the certainty that pulmonary angiography allows. Finally, the article proposes an algorithm that may be acceptable to patients and clinicians alike if safety is confirmed in future prospective studies.
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Affiliation(s)
- T R Wolfe
- Division of Emergency Medicine, University of Utah School of Medicine, Salt Lake City, UT 84132, USA.
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21
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Foley MI, Moneta GL. Venous Disease and Pulmonary Embolism. Surgery 2001. [DOI: 10.1007/978-3-642-57282-1_49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hatabu H, Tadamura E, Prasad PV, Chen Q, Buxton R, Edelman RR. Noninvasive pulmonary perfusion imaging by STAR-HASTE sequence. Magn Reson Med 2000; 44:808-12. [PMID: 11064417 DOI: 10.1002/1522-2594(200011)44:5<808::aid-mrm20>3.0.co;2-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The STAR-HASTE sequence has been shown to be useful for perfusion imaging in areas that are plagued by magnetic susceptibility artifacts. Pulmonary perfusion imaging with this technique was attempted in this study. Quantitative analysis was also conducted, using an appropriate kinetic model in one subject. In six healthy subjects, gradual enhancement was observed in pulmonary artery to distal lung parenchyma when inflow time was increased. Our initial results suggest that noninvasive evaluation of pulmonary perfusion by magnetic resonance imaging without administration of an exogenous agent is possible.
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Affiliation(s)
- H Hatabu
- Department of Radiology, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
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23
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Yucel EK, Anderson CM, Edelman RR, Grist TM, Baum RA, Manning WJ, Culebras A, Pearce W. AHA scientific statement. Magnetic resonance angiography : update on applications for extracranial arteries. Circulation 1999; 100:2284-301. [PMID: 10578005 DOI: 10.1161/01.cir.100.22.2284] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Woodard PK, Yusen RD. Diagnosis of pulmonary embolism with spiral computed tomography and magnetic resonance angiography. Curr Opin Cardiol 1999; 14:442-7. [PMID: 10500908 DOI: 10.1097/00001573-199909000-00014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Radiologic imaging techniques such as contrast-enhanced spiral computed tomography (CT) and magnetic resonance (MR) angiography provide noninvasive means of diagnosing pulmonary thromboembolic disease. In addition, both techniques permit direct visualization of the embolus. Although imperfect, both CT and MR angiography in various circumstances fit diagnostic pathways for pulmonary embolism detection. Recent advances in both CT (multidetector ring spiral units and electron beam) and MR technology allow not only depiction of the pulmonary arteries, but also are capable of providing information about the lower extremity deep venous system in a single examination.
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Affiliation(s)
- P K Woodard
- Chest Division, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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Tapson VF, Carroll BA, Davidson BL, Elliott CG, Fedullo PF, Hales CA, Hull RD, Hyers TM, Leeper KV, Morris TA, Moser KM, Raskob GE, Shure D, Sostman HD, Taylor Thompson B. The diagnostic approach to acute venous thromboembolism. Clinical practice guideline. American Thoracic Society. Am J Respir Crit Care Med 1999; 160:1043-66. [PMID: 10471639 DOI: 10.1164/ajrccm.160.3.16030] [Citation(s) in RCA: 240] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Stein PD, Hull RD, Pineo GF. The role of newer diagnostic techniques in the diagnosis of pulmonary embolism. Curr Opin Pulm Med 1999; 5:212-5. [PMID: 10407689 DOI: 10.1097/00063198-199907000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Among the evolving techniques for the diagnosis of acute pulmonary embolism, contrast enhanced spiral CT takes a particularly prominent role because it is available at most centers, it images the pulmonary embolism directly, and it is minimally invasive. It has not yet been fully evaluated, however. Magnetic resonance angiography also has appeal for similar reasons. Few patients have been studied, however. Magnetic resonance angiography for pulmonary embolism is still in the early testing phase. Transesophageal echocardiography can image pulmonary embolism in central pulmonary arteries, but preliminary tests suggest that it has a low negative predictive value and cannot be used to exclude pulmonary embolism. Finally, it seems that a rapid and sensitive technique for measuring d-dimer may now be available, which may assist in eliminating the diagnosis of acute pulmonary embolism in a significant percentage of patients in whom the diagnosis is suspected.
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Affiliation(s)
- P D Stein
- Henry Ford Heart and Vascular Institute, Detroit, Michigan, USA.
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Hurst DR, Kazerooni EA, Stafford-Johnson D, Williams DM, Platt JF, Cascade PN, Prince MR. Diagnosis of pulmonary embolism: comparison of CT angiography and MR angiography in canines. J Vasc Interv Radiol 1999; 10:309-18. [PMID: 10102196 DOI: 10.1016/s1051-0443(99)70036-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To compare the sensitivity and specificity of helical computed tomographic angiography (CTA), CTA with multiplanar reconstructions (MPR)/three-dimensional-shaded surface display (3D-SSD), and gadolinium-enhanced magnetic resonance angiography (MRA) for pulmonary embolism (PE) detection. MATERIALS AND METHODS Gelatin sponge emboli were introduced into the femoral veins of seven dogs and conventional digital subtraction angiography (CA), CTA, and MRA performed. Images from CTA, CTA with MPR/3D-SSD, and MRA were reviewed for the presence of PE in lobar and segmental arteries, and subsegmental zones. Postmortem angiography and CA were the gold standard. RESULTS There were 50 emboli in the 294 vessels/zones analyzed. The sensitivity of CTA for the two readers was 76% (95% confidence interval [CI]; 64%-88%) and 64% (95% CI; 50%-78%), and for the two MRA readers was 52% (95% CI; 38%-66%) and 48% (95% CI; 34%-62%). CTA was more sensitive than MRA when PE were subdivided by vessel caliber. Specificity was high for CTA and MRA among all readers (98.8%-99.6%). MPR/3D-SSD did not improve results of axial CT. MRA perfusion defects were 46% and 47% sensitive and 100% specific. Interobserver agreement was high for CTA and MRA (kappa 0.92 and 0.93, respectively). The average diameter of vessels with emboli was 3.7 mm +/- 1.06. CONCLUSION Helical CTA is more sensitive than three-dimensional gadolinium-enhanced MRA for the detection of PE. Both CTA and MRA are highly specific for PE detection and demonstrate high interobserver agreement. MPR/3D-SSD did not increase CTA performance over axial images alone.
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Affiliation(s)
- D R Hurst
- Department of Radiology, The University of Michigan Medical Center, Ann Arbor 48109-0326, USA
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Abstract
Magnetic resonance angiography (MRA) has been established as a powerful noninvasive imaging modality. Its applications to the study of the pulmonary vasculature have been hampered by a multitude of factors, such as respiratory and cardiac motion artifacts, saturation problems, long acquisition times, and limited spatial resolution. The recent introduction of contrast-enhanced MRA (CE-MRA) has greatly improved the potential for possible investigation of the pulmonary arteries under clinical conditions. Three-dimensional sequences with minimum TR and TE, a flip angle between 20 degrees and 60 degrees, and minimum slice thickness can be considered an optimal approach for breath-hold imaging combined with the automatic injection of contrast medium. Early studies have demonstrated the superiority of CE-MRA over nonenhanced techniques. The major indication for CE-MRA of the pulmonary vasculature is pulmonary embolism. Here a sensitivity of 85% and specificity of 95% can be obtained. It can be complemented by perfusion imaging, ventilation imaging, functional measurements of the right ventricle, and MR venography of the pelvic and femoral veins. Blood pool contrast agents will open new perspectives in the future. This article reviews the technical aspects of CE-MRA of the pulmonary vasculature, pathologic findings, and their interpretation as well as present and future clinical applications.
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Affiliation(s)
- H U Kauczor
- Department of Radiology, Johannes Gutenberg-University Mainz, Germany.
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Carriero A, Marano R, Fossaceca R, Magarelli N, Bonomo L. Pulmonary veins: magnetic resonance angiography anatomy. MAGMA (NEW YORK, N.Y.) 1998; 6:2-6. [PMID: 9794283 DOI: 10.1007/bf02662505] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE to optimize magnetic resonance angiography technique for the selective study of the anatomy of pulmonary veins. MATERIALS AND METHODS twenty consecutive patients (13 males and seven females; mean age 30.5 years) prospectively studied were enrolled. Magnetic resonance angiography was performed using a 1 T superconductive magnet and three dimensional time of flight technique (3D TOF). Imaging with steady-state free precession sequence during intravenous infusion of contrast medium (Gd DTPA 0.2 mmol kg(-1)) administration was employed using the following parameters: FA 20 degrees, TR 58 ms, TE 6 ms, MA 192 x 256, NEX 1, slice thickness 4 mm and slice orientation on the Z and Y planes. RESULTS in the right lung magnetic resonance angiography well visualized 124 venous vessels on the coronal plane versus 106 venous vessels on the sagittal plane, whereas in the left lung magnetic resonance angiography visualized 96 vessels on the coronal plane versus 44 visualized on the sagittal plane. Our data suggest that 3D time of flight with contrast medium is a promising evaluation technique for pulmonary veins, and that combined evaluation of acquisitions on coronal and sagittal planes allows the visualization of a higher number of venous vessels. CONCLUSION 3D time of flight with contrast medium and without breath-hold permits to visualize a venous vascular map of the lungs.
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Affiliation(s)
- A Carriero
- Department of Radiology, University of Chieti, Ospedale SS. Annunziata, Italy
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Abstract
Recent advances in MR pulmonary angiography and MR perfusion imaging are reviewed, focusing on two principal areas of technical development: (1) the availability of MR scanners equipped with enhanced gradient systems; and (2) new trends in MR angiography using gadolinium contrast agents or labeling of blood with an inversion recovery radiofrequency pulse in place of the more traditional methods using naturally flowing spins as the source of intravascular signal. These recent developments in MR have significant potential for clinical imaging of the pulmonary vasculature, particularly for the diagnosis of pulmonary embolism, and are now opening windows to functional MR imaging of the lung.
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Affiliation(s)
- H Hatabu
- Department of Radiology and Nuclear Medicine, Kyoto University Hospital, Sakyo-Ku, Japan
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Abstract
Magnetic resonance imaging (MRI) has the unique ability to demonstrate pulmonary emboli, venous thrombosis, and normal pulmonary arteries in a single noninvasive study. Spin echo and gradient echo pulse sequences take advantage of the natural high contrast between flowing blood and intraluminal thrombus or embolus. Magnetic resonance angiographic (MRA) techniques offer three-dimensional display of the pulmonary vasculature. Each of these techniques may be viewed in cinematic fashion to depict hemodynamic changes associated with the cardiac cycle. Clinical studies have demonstrated sensitivity in the 75% to 100% range and specificities between 42% and 90% depending on technique. MRI technology is still rapidly advancing and clinical accuracy will no doubt improve as experience with new techniques develops. At present, MRI should play a complimentary role to conventional methods of diagnosing thromboembolic disease.
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Affiliation(s)
- W A Erdman
- Department of Radiology, University of Texas, Southwestern Medical Center at Dallas 75235-8896, USA
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Gallagher EJ. The diagnosis of pulmonary embolism: incremental improvements in the emperor's wardrobe. Acad Emerg Med 1997; 4:847-51. [PMID: 9305423 DOI: 10.1111/j.1553-2712.1997.tb03805.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Li KC, Pelc LR, Napel SA, Goris ML, Lin DT, Song CK, Leung AN, Rubin GD, Hollett MD, Harris DP. MRI of pulmonary embolism using Gd-DTPA-polyethylene glycol polymer enhanced 3D fast gradient echo technique in a canine model. Magn Reson Imaging 1997; 15:543-50. [PMID: 9253998 DOI: 10.1016/s0730-725x(97)00001-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study was to evaluate the accuracy of MR angiography (MRA) using a Gd-DTPA-polyethylene glycol polymer (Gd-DTPA-PEG) with a 3D fast gradient echo (3D fgre) technique in diagnosing pulmonary embolism in a canine model. Pulmonary emboli were created in six mongrel dogs (20-30 kg) by injecting tantalum oxide-doped autologous blood clots into the femoral veins via cutdowns. MRI was performed with a 1.5 T GE Signa imager using a 3D fgre sequence (11.9/2.3/15 degrees) following intravenous injection of 0.06 mmol Gd/kg of Gd-DTPA-PEG. The dogs were euthanized and spiral CT of the lungs were then obtained on the deceased dogs. The MRI images were reviewed independently and receiver-operating-characteristic (ROC) curves were used for statistical analysis using spiral CT results as the gold standard. The pulmonary emboli were well visualized on spiral CT. Out of 108 pulmonary segments in the six dogs, 24 contained emboli >2 mm and 27 contained emboli < or = 2 mm. With unblinded review, MRI detected 79% of emboli >2 mm and only 48% of emboli < or = 2 mm. The blinded review results were significantly worse. Gd-DTPA-PEG enhanced 3D fgre MRI is potentially able to demonstrate pulmonary embolism with fairly high degree of accuracy, but specialized training for the interpretations will be required.
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Affiliation(s)
- K C Li
- Department of Diagnostic Radiology, Stanford University School of Medicine, CA 94305, USA
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Huynh TV, Bergin CJ, Hauschildt J, Konopka RG, Bloor C, Buxton R. Magnetic resonance detection of acute pulmonary emboli in a canine model with pathologic correlation. Acad Radiol 1996; 3:1019-24. [PMID: 9017017 DOI: 10.1016/s1076-6332(96)80036-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
RATIONALE AND OBJECTIVES The authors evaluated the accuracy of magnetic resonance (MR) imaging in depicting acute pulmonary emboli at the lobar, segmental, and subsegmental levels. METHODS The authors induced 29 autologous emboli in five dogs and confirmed their location with angiography and anatomic dissection. MR images obtained with four sequences were independently evaluated by two radiologists to detect emboli in each vascular segment. Sensitivities, specificities, and accuracies were calculated at segmental and lobar levels. RESULTS The fast short-tau inversion-recovery images provided the greatest conspicuity and highest overall accuracy (reader 1 = 74.3%, reader 2 = 80%). Accuracy of two-dimensional fast multiplanar spoiled gradient-recalled-echo images was limited by spatial resolution (reader 1 = 71.4%, reader 2 = 74.3%). The fast spin-echo T2-weighted and spin-echo T1-weighted sequences were intermediate in their depiction of acute emboli. Similar results were seen at the lobar level. CONCLUSION MR images depict acute pulmonary embolism at the segmental and lobar levels with reasonable accuracy. Fast short-tau inversion-recovery sequences provided the greatest sensitivity and accuracy.
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Affiliation(s)
- T V Huynh
- Department of Radiology, University of California, San Diego 92103-8756, USA
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Hatabu H, Gaa J, Kim D, Li W, Prasad PV, Edelman RR. Pulmonary perfusion: qualitative assessment with dynamic contrast-enhanced MRI using ultra-short TE and inversion recovery turbo FLASH. Magn Reson Med 1996; 36:503-8. [PMID: 8892200 DOI: 10.1002/mrm.1910360402] [Citation(s) in RCA: 159] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The accurate assessment of pulmonary perfusion is especially important in the evaluation of patients with suspected pulmonary embolism, a common and potentially lethal disorder that can be treated by aggressive anticoagulation. In this study, we demonstrate for the first time the use of MR to image pulmonary perfusion in humans by using dynamic imaging after contrast administration. The technique, which uses an inversion recovery turbo FLASH sequence with ultrashort TE (1.4 ms) and 1-s temporal resolution, was tested in a series of eight healthy subjects and in a porcine model of pulmonary embolism. After the administration of gadopentetate dimeglumine in humans and animal models, there was serial enhancement of the systemic veins, right atrium, right ventricle, and pulmonary arteries. The pulmonary arterial tree was visualized beyond the segmental branches, followed by a gradual diffuse increase in signal intensity of the lung parenchyma over a period of 4.0-7.0 s. Pulmonary circulation times ranged from 3.0-3.4 s. Whereas a high dose (20 or 40 ml) of contrast agent tended to produce the most intense parenchymal enhancement, a low dose (5 ml) was best for showing recirculation. In the animal model, a perfusion defect due to a pulmonary embolus was clearly shown and confirmed by cine angiography. It is concluded that MRI of lung perfusion is feasible. With further development, perfusion MRI could eventually have a significant clinical role in the diagnostic evaluation of pulmonary embolism.
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Affiliation(s)
- H Hatabu
- Department of Radiology, Beth Israel Hospital, Boston, MA 02215, USA
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Wang Y, Rossman PJ, Grimm RC, Wilman AH, Riederer SJ, Ehman RL. 3D MR angiography of pulmonary arteries using real-time navigator gating and magnetization preparation. Magn Reson Med 1996; 36:579-87. [PMID: 8892211 DOI: 10.1002/mrm.1910360413] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An ECG-triggered magnetization-prepared segmented 3D fast gradient echo sequence was developed to perform pulmonary arterial MR angiography. A selective inversion recovery pulse was used in the magnetization preparation to suppress venous vasculature. A real-time gating technique based on navigator echoes was implemented to reduce respiration effects. Pencil-beam navigator echoes were acquired immediately before and after the readout train and processed in real-time to dynamically measure the diaphragm position, which was used to control data acquisition with an accept-or-reject-reacquire logic. In a study of 10 volunteers, a gated 3D acquisition with 28 slices required on average approximately 4 min of acquisition time, and six to seven segmental arteries related to the interlobar trunk of the pulmonary artery were depicted. The use of SIR pulse reduced venous signal by 99%. The gated acquisitions were superior to the ungated acquisitions (n = 10, P < 0.005). The real-time navigator gating technique is effective for reduction of respiration effects and thereby makes high resolution 3D MRA of the pulmonary arteries feasible.
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Affiliation(s)
- Y Wang
- Diagnostic Radiology, Mayo Clinic, Rochester, MN 55905, USA
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Abstract
Recent technical improvements have made pulmonary MR angiography (MRA) feasible. The technique is attractive because it is noninvasive, provides a full three-dimensional (3D) display of the pulmonary vasculature, and potentially can be combined with MR venography of the lower extremities and pelvis for the comprehensive diagnosis of thromboembolism. Approaches to acquiring pulmonary MR angiograms are currently being developed and include both two-dimensional and 3D time-of-flight methods, breath-hold and non-breath-hold techniques, and the use of gadolinium-based contrast enhancement. The results of initial studies using pulmonary MRA for the detection of pulmonary embolism are encouraging, but they must be evaluated in conjunction with newly developed fast CT scanning techniques. This article reviews the state of development of pulmonary MRA, the current clinical applications of the technique, and the prospects for future development.
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Affiliation(s)
- W B Gefter
- Department of Radiology, University of Pennsylvania Medical Center, Philadelphia 19104, USA
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Smith TP, Lee VS, Hudson ER, Newman GE, Payne CS, Suhocki PV, McDermott VG, Stackhouse DJ. Prospective evaluation of pulmonary artery pressures during pulmonary angiography performed with low-osmolar nonionic contrast media. J Vasc Interv Radiol 1996; 7:207-12. [PMID: 9007799 DOI: 10.1016/s1051-0443(96)70763-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
PURPOSE To determine the effects of pulmonary angiography performed with low-osmolar, nonionic contrast media on pulmonary artery pressures. PATIENTS AND METHODS In a prospective, uncontrolled clinical trial, pulmonary artery pressures (systolic, diastolic, mean) of 116 patients referred for pulmonary angiography were recorded before and 1 and 5 minutes after injection of contrast material. RESULTS There was a statistically significant rise in systolic, diastolic, and mean pulmonary artery pressure at 1 minute (4.6, 3.4, 4.1 mm Hg, respectively) and 5 minutes (3.8, 2.7, 3.4 mm Hg, respectively) after the initial contrast material injection (P < .05). Increases were smaller with additional injections. Systolic pressure changes at 1 and 5 minutes after the first injection were linearly dependent on the volume of contrast material injected (P < .05). There was no statistically significant difference in the increase in pulmonary artery pressure between patients with pulmonary embolus or pulmonary arterial hypertension and those without. CONCLUSION There is a small but statistically significant rise in pulmonary artery pressure after injection of low-osmolar, nonionic contrast material for pulmonary angiography; it is unlikely to be of clinical significance.
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Affiliation(s)
- T P Smith
- Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
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Sostman HD, Layish DT, Tapson VF, Spritzer CE, DeLong DM, Trotter P, MacFall JR, Patz EF, Goodman PC, Woodard PK, Foo TK, Farber JL. Prospective comparison of helical CT and MR imaging in clinically suspected acute pulmonary embolism. J Magn Reson Imaging 1996; 6:275-81. [PMID: 9132089 DOI: 10.1002/jmri.1880060203] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The purpose of this study is to compare sensitivity and specificity of helical CT and MR imaging for detecting acute pulmonary embolism(PE). Patients who were suspected clinically of having PE were randomly assigned to undergo either helical contrast-enhanced CT or gradient-echo MR (if one modality was contraindicated, the patient was assigned to the other.) Patients were considered to have PE if they had: 1) high-probability V-Q scan and low clinical probability of PE; 2) pulmonary angiogram positive for PE. Patients were considered not to have PE if they had either:1)normal V-Q scan; 2) low probability V-Q scan and low clinical probability of PE; or 3) pulmonary angiogram negative for PE. The CT and MR images were read randomly and independently by five radiologists with varying levels of CT and MR experience. Twenty eight patients underwent CT and 25 MR. A total of 21 patients underwent pulmonary angiography (6 had PE, 15 did not have PE). Of the other 32 patients, 15 had high probability scan/high clinical probability and 17 had low probability scan/low clinical probability. For the five observers, the average sensitivity of CT was 75% and of MR 46%; the average specificity of CT was 89% and of MR 90%. Experience with vascular MR and enhanced CT influenced diagnostic accuracy. For the two vascular MR experts, average sensitivity and specificity of MR were 71% and 97%, and of CT 73% and 97%. In this pilot study, when CT and MR were interpreted with comparable expertise, they had similar accuracy for detecting pulmonary embolism.
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Affiliation(s)
- H D Sostman
- Department of Radiology, New York Hospital--Cornell Medical Center, NY, USA
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Wolff K, Bergin CJ, King MA, Ghadishah E, Sung DW, Clopton P, Bookstein JJ, Auger WR, Moser KM. Accuracy of contrast-enhanced magnetic resonance angiography in chronic thromboembolic disease. Acad Radiol 1996; 3:10-7. [PMID: 8796634 DOI: 10.1016/s1076-6332(96)80325-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
RATIONALE AND OBJECTIVES We evaluated the accuracy of contrast-enhanced magnetic resonance (MR) angiography in demonstrating the findings of chronic pulmonary thromboembolism (CPTE) compared with conventional pulmonary angiography. METHODS We examined 18 patients with CPTE proved by conventional pulmonary angiography and 16 healthy control patients. T1-weighted and single-breathhold, two-dimensional multiplanar spoiled gradient-recalled pulmonary images were obtained after injection of gadopentetate dimeglumine. Images were interpreted independently by two radiologists. RESULTS All patients with CPTE were identified on MR angiography images by both readers. Sensitivity and specificity for MR angiography in diagnosing abnormal segments were 76% and 95% for reader 1 and 68% and 93% for reader 2, respectively. Sensitivity and specificity for MR angiography in depicting abnormal lobes were 83% and 96% for reader 1 and 82% and 93% for reader 2, respectively. Interobserver agreement was high; kappas for abnormal segments and abnormal lobes were .72 and .84, respectively. The T1-weighted spin-echo images demonstrated a mosaic signal intensity pattern in all patients with CPTE. CONCLUSION Contrast-enhanced MR angiography accurately depicts abnormal segments and lobes in occlusive vascular disease and clearly distinguishes between patients with CPTE and those with healthy lungs.
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Affiliation(s)
- K Wolff
- Department of Radiology, University of California, San Diego Medical Center 92103-8756, USA
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De Bruyn VH, Bergmann SR, Keyt BA, Sobel BE. Visualization of thrombi in pulmonary arteries with radiolabeled, enzymatically inactivated tissue-type plasminogen activator. Circulation 1995; 92:1320-5. [PMID: 7648681 DOI: 10.1161/01.cir.92.5.1320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Despite the high frequency of pulmonary thromboembolism and its significant morbidity and mortality, diagnosis remains suboptimal. We have been developing a method for prompt detection with the use of radiolabeled, inactivated tissue-type plasminogen activator (TPA) and performed the present study to determine whether its use permits rapid scintigraphic visualization of pulmonary thrombi in vivo. METHODS AND RESULTS The thrombolytic, but not fibrin-binding, property of TPA was inactivated with a tripeptide chloromethyl ketone (YPACK) that had already been iodinated with 123I to radiolabel the TPA. Pulmonary arterial thrombosis was induced in nine dogs with the use of guide wires modified to provide thrombogenic tips. 123I-YPACK-TPA (1.1 to 7.8 mCi, 0.5 to 7.8 mg) was infused for 5 minutes into either the systemic or the pulmonary circulation. Clearance of radioactivity from the blood was rapid and indistinguishable from that of unlabeled, thrombolytically active TPA, with only 6.7 +/- 1.0% (mean +/- SEM) of peak radioactivity remaining after 60 minutes and minimal release of labeled fragments from the liver during this interval. Thrombi were visualized with single photon emission computed tomography and/or planar imaging 40 to 120 minutes after infusion of tracer in all seven animals given at least 3.7 mCi of 123I-YPACK-TPA. Ratios of radioactivity in thrombus (wet mass, 610 +/- 64 mg) to blood were high (14 +/- 3:1). CONCLUSIONS The use of radiolabeled TPA in which thrombolytic activity is inactivated permits prompt scintigraphic detection of thrombi in pulmonary arteries in vivo.
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Affiliation(s)
- V H De Bruyn
- Cardiovascular Division, Washington University School of Medicine, St Louis, Mo 63110, USA
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Laissy JP, Bancal C, Sekkal S, Chillon S, Berger JF, Limot O, Tebboune D, Henry-Feugeas MC, Falise B, Aubier M. Pulmonary MR angiography at 1.0 T: early results with k-space segmented and post-contrast TurboFLASH two-dimensional time-of-flight sequences. Eur J Radiol 1995; 20:9-15. [PMID: 7556263 DOI: 10.1016/0720-048x(95)00626-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE To evaluate the combined performance of two time-of-flight methods in imaging the pulmonary arteries. MATERIALS AND METHODS This study was prospectively conducted in 28 patients suspected for pulmonary embolism (PE). Sixteen patients were free of pulmonary vascular disease, and 12 had pulmonary vascular disease as demonstrated by pulmonary angiography. To reduce artifacts caused by cardiac and respiratory motion, MR images were acquired in all subjects using bi-dimensional (2D), gradient-recalled echo (GRE), breath-hold techniques. Sagittal thin (6-mm) sections obtained with ECG gating, k-space segmentation and incremented flip-angles (TONE), and coronal thick (15-mm) sections obtained after a unique injection of Gadolinium chelate were used. RESULTS High quality images were obtained in all 16 (100%) subjects free of pulmonary disease with both techniques, and in 10 and 12 (87% and 100%) patients suspected for pulmonary artery disease with sagittal and coronal Gd-enhanced MRA, respectively. In patients free of pulmonary disease, TONE images exhibited distal pulmonary arteries with 2.1 subsegmental divisions on average, whereas Gd-enhanced TurboFLASH images were the most accurate to identify proximal pulmonary arteries within the mediastinum, even if only 0.8 subsegmental divisions were seen on average. A correct diagnosis of pulmonary embolism was obtained in all cases but one, with use of both MRA techniques, with an overall accuracy of 86%. CONCLUSION The association of segmented sagittal GRE images and coronal first-pass Gd-enhanced GRE images can provide information upon normal and diseased pulmonary arteries within the mediastinum until subsegmental pulmonary branches, even in patients with short-breathing. Further studies of patients with various pulmonary artery diseases will confirm whether this technique makes pulmonary MRA feasible in clinical routine situations.
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Affiliation(s)
- J P Laissy
- Department of Radiology, Centre Hospitalier et Universitaire Bichat-Claude Bernard, Paris, France
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Laissy JP, Assayag P, Henry-Feugeas MC, Tebboune D, Berger JF, Limot O, Falise B, Chillon S, Valere PE, Schouman-Claeys E. Pulmonary time-of-flight MR angiography at 1.0 T: comparison between 2D and 3D tone acquisitions. Magn Reson Imaging 1995; 13:949-57. [PMID: 8583873 DOI: 10.1016/0730-725x(95)02001-a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The purpose of this study was to compare the performance of 2D vs. 3D time-of-flight (TOF) methods in imaging the normal pulmonary arteries with commercially available 1.0 T equipment. The study was conducted in 20 volunteers and 7 patients with suspected pulmonary embolism (PE). To reduce artifacts caused by cardiac and respiratory motion, MR images were acquired in volunteers using two-dimensional (2D), gradient-recalled echo (GRE), breath-hold techniques, and three-dimensional (3D) acquisitions. Sagittal thin (6-MM) segmented k-space 2D sections obtained with cardiac gating during systole (turboFLASH, TR/TE9/6 ms, 14 segments of 9 lines) and incremented flip-angles (TONE), and 50-mm 3D volume TONE acquisitions with 32 partitions (FISP, TR/TE34/10ms) were successively performed. In the second phase of the study, patients were examined only with the 3D technique. Images of volunteers were qualitatively and quantitatively analyzed. S/N ratios were statistically compared by means of the paired-sample Wilcoxon ranked-signed test, a value of p < .05 being significant. In volunteers, 3D acquisitions displayed significantly more segment-order pulmonary arteries on average than did 2d acquisitions displayed significantly more segment-order pulmonary arteries on average than did 2D acquisitions (2.95 +/- 0.64 vs. 2.2 +/- 0.85, respectively; p < .01). Moreover, the signal intensity of arteries within the lungs was less homogeneous in the 2D than in the 3D technique, with a signal intensity ratio between peripheral and proximal arteries of 63% +/- 7% and 73% +/- 2%, respectively (p < .05). In patients, no erroneous diagnoses were obtained using the 3D technique. 3D images of normal lungs provide MR angiograms of better quality than do 2D images, and require less contribution from subjects because they are performed in free breathing. Ongoing improvements in MR sequences and further studies are now necessary to assess the value of 3D TONE MRA in the diagnosis of PE.
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Affiliation(s)
- J P Laissy
- Department of Radiology, Centre Hospitalier, Paris
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