Abstract:
OBJECTIVES:Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a method to heat lesions noninvasively to a stable, elevated temperature and a well-suited method to induce local hyperthermia (41°C-43°C) in deep-seated tissues. Magnetic Resonance (MR) imaging provides therapy planning on anatomical images and offers temperature feedback based on near-real-time MR thermometry. Although constant acquisition of MR thermometry data is crucial to ensure prolonged hyperthermia, it limits the freedom to perform measurements of other MR parameters, which are of interest during hyperthermia treatments. In image-guided drug delivery applications, co-encapsulation of paramagnetic MR contrast agents with a drug inside temperature-sensitive liposomes (TSLs) allows to visualize hyperthermia-triggered drug delivery through changes of the longitudinal relaxation rate R1. While the drug accumulates in the heated tumor tissue, R1 changes can be used for an estimate of the tumor drug concentration. The main objective of this study was to demonstrate that interleaved MR sequences are able to monitor temperature with an adequate temporal resolution and could give a reasonable estimate of the achieved tumor drug concentration through R1 changes. To this aim, in vitro validation tests and an in vivo proof-of-concept study were performed. MATERIALS AND METHODS:All experiments were performed on a clinical 3-T MR-HIFU system adapted with a preclinical setup. The validity of the R1 values and the temperature maps stability were evaluated in phantom experiments and in ex vivo porcine muscle tissue. In vivo experiments were performed on rats bearing a 9L glioma tumor on their hind limb. All animals (n = 4 HIFU-treated, n = 4 no HIFU) were injected intravenously with TSLs co-encapsulating doxorubicin and gadoteridol as contrast agent. The TSL injection was followed by either 2 times 15 minutes of MR-HIFU-induced hyperthermia or a sham treatment. R1 maps were acquired before, during, and after sonication, using a single slice Inversion Recovery Look-Locker (IR-LL) sequence (field of view [FOV], 50 × 69 mm; in-plane resolution, 0.52 × 0.71 mm; slice thickness, 3 mm; 23 phases of 130 milliseconds; 1 full R1 map every 2 minutes). The R1 maps acquired during treatment were interleaved with 2 perpendicular proton resonance frequency shift (PRFS) MR thermometry slices (dynamic repetition time, 8.6 seconds; FOV, 250 × 250 mm; 1.4 × 1.4 mm in-plane resolution; 4 mm slice thickness). Tumor doxorubicin concentrations were determined fluorometrically. RESULTS:In vitro results showed a slight but consistent overestimation of the measured R1 values compared with calibrated R1 values, regardless whether the R1 was acquired with noninterleaved IR-LL or interleaved. The average treatment cell temperature had a slightly higher temporal standard deviation for the interleaved PRFS sequence compared with the noninterleaved PRFS sequence (0.186°C vs 0.101°C, respectively). The prolonged time in between temperature maps due to the interleaved IR-LL sequence did not degrade the temperature stability during MR-HIFU treatment (Taverage = 40.9°C ± 0.3°C). Upon heat treatment, some tumors showed an R1 increase in a large part of the tumor while other tumors hardly showed any ΔR1. The tumor doxorubicin concentration showed a linear correlation with the average ΔR1 during both sonications (n = 8, Radj = 0.933), which was higher than for the ΔR1 measured after tumor cooldown (averaged for both sonications, n = 8, Radj = 0.877). CONCLUSIONS:The new approach of interleaving different MR sequences was applied to simultaneously acquire R1 maps and PRFS thermometry scans during a feedback-controlled MR-HIFU-induced hyperthermia treatment. Interleaved acquisition did not compromise speed or accuracy of each scan. The ΔR1 acquired during treatment was used to visualize and quantify hyperthermia-triggered release of gadoteridol from TSLs and better reflected the intratumoral doxorubicin concentrations than the ΔR1 measured after cooldown of the tumor, exemplifying the benefit of interleaving R1 maps with temperature maps during drug delivery. Our study serves as an example for interleaved MR acquisition schemes, which introduce a higher flexibility in speed, sequence optimization, and timing.
journal_name
Invest Radioljournal_title
Investigative radiologyauthors
Kneepkens E,Heijman E,Keupp J,Weiss S,Nicolay K,Grüll Hdoi
10.1097/RLI.0000000000000392subject
Has Abstractpub_date
2017-10-01 00:00:00pages
620-630issue
10eissn
0020-9996issn
1536-0210journal_volume
52pub_type
杂志文章abstract::Perfluoroctylbromide (PFOB), a radiopaque reticuloendothelial system contrast media for computed tomography, has been shown to accumulate in macrophages. In the current study PFOB was tested in rabbits as an abscess imaging agent. Two abscesses were induced in each of 24 rabbits, one in the liver and the other in the ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198409000-00017
更新日期:1984-09-01 00:00:00
abstract:OBJECTIVES:The aim of this study was to evaluate the effect of structured reports (SRs) in comparison to nonstructured, free-text (FT) rectal magnetic resonance imaging (MRI) reports in patients with histologically proven rectal cancer and potential effects of both types of reporting on referring surgeons' satisfaction...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000336
更新日期:2017-04-01 00:00:00
abstract:OBJECTIVES:The aim of this study was to investigate the impact on metal artifacts and dose efficiency of using a tin filter in combination with high-energy threshold (TH) images of a photon-counting detector (PCD) computed tomography (CT) system. MATERIALS AND METHODS:A 3D-printed spine with pedicle screws was scanned...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000535
更新日期:2019-04-01 00:00:00
abstract::The importance of evaluating medical student performance has been widely addressed in the medical education literature. Multiple-choice examinations are the preferred method of testing because they are easy to administer and score. Development of parallel or equivalent pre- and post-examinations provides objective inf...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1986-09-01 00:00:00
abstract:OBJECTIVE:This study aims for targeted biopsy validation of magnetic resonance fingerprinting (MRF) and diffusion mapping for characterizing peripheral zone (PZ) prostate cancer and noncancers. MATERIALS AND METHODS:One hundred four PZ lesions in 85 patients who underwent magnetic resonance imaging were retrospectivel...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000569
更新日期:2019-08-01 00:00:00
abstract::Prior studies of the opacification-phase effects of left ventricular (LV) injection of angiographic contrast medium (CM) on LV size and function have yielded discrepant results. A sensitive ultrasonic technique was used to measure LV dimension (Di) in 10 open-chest dogs with physiologic heart rates, and injection of s...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198209000-00009
更新日期:1982-09-01 00:00:00
abstract:OBJECTIVES:Transcatheter arterial embolization (TAE) is used for the treatment of patients with malignant liver tumors. However, the proangiogenesis effect of TAE-associated hypoxia has not been adequately studied. The goal of this study was to determine angiogenic activity in tumors subjected to TAE by evaluating the ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/01.rli.0000209663.00629.8a
更新日期:2006-06-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To test noninvasive inductive heating of implanted vascular stents as an alternative approach for reduction or prevention of neointimal hyperplasia. METHODS:Calorimetric pretests were performed to get an orientation on the different parameters of influence for inductive heating of stents. The ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/01.rli.0000117881.42422.72
更新日期:2004-05-01 00:00:00
abstract:OBJECTIVES:Intra-arterial digital subtraction angiography (IA-DSA), an invasive procedure, is the current reference examination after percutaneous transluminal angioplasty and stenting for the detection of in-stent restenosis (ISR). In this phantom study, we evaluated flat-panel angiographic computed tomography after i...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e318276db43
更新日期:2013-02-01 00:00:00
abstract::Due to the nature of three-dimensional Fourier transform (3-DFT) data acquisition in magnetic resonance imaging (MRI), the spatial relation between a resolved volume element (a voxel) and the object can be manipulated easily. Those manipulations have practical consequences in terms of registering slice positions with ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199012000-00006
更新日期:1990-12-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:At many institutions, three-dimensional magnetic resonance imaging (MRI) is routinely used for examination of the knee. Multiplanar reconstruction (MPR) is a method of displaying three-dimensional datasets. The authors assessed the usefulness of MPR for evaluating knee MRI datasets by comparing...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199302000-00011
更新日期:1993-02-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Target-specific magnetic resonance (MR) contrast agents are being developed to improve the accuracy of MR imaging. The purpose of this study was to determine the mechanism of cell uptake, and modes of intracellular trafficking of a prototypical iron oxide label (RMA) used in the synthesis of so...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199510000-00006
更新日期:1995-10-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To evaluate the imaging characteristics of various iliac artery stents and stent-grafts in a multislice, computed tomography angiography (MSCTA) phantom study. METHODS:Twelve types of stents and three stent-grafts made of different materials (steel, nitinol, tantalum, cobalt-based alloy) were ...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200112000-00004
更新日期:2001-12-01 00:00:00
abstract::Over the past 120 years, continuous developments in medical imaging has improved diagnosis and treatment for many diseases and has thereby improved treatment outcome and quality of life of many patients. The number of computed tomography (CT) examinations is today increasing by 4% per year worldwide, for a total of ap...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000696
更新日期:2020-09-01 00:00:00
abstract:OBJECTIVE:To investigate the feasibility of an 80-kVp protocol using a moderate concentration contrast material (MC-CM) for cerebral computed tomography angiography by comparison with a conventional 120-kVp protocol using a high concentration contrast material (HC-CM). MATERIALS AND METHODS:Attenuation values and sign...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e31823076a4
更新日期:2012-02-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Two independent gold standards and diagnoses from three-dimensional computed tomography (CT) images were used to examine the possibility that craniosynostosis is a binary abnormality that potentially may be diagnosed without error. METHODS:Surgical reports, histology of excised sutures, and th...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199410000-00005
更新日期:1994-10-01 00:00:00
abstract::An ultrasound phantom was constructed simulating fetal femurs in amniotic fluid. Bones of 26, 36, 50, 58, and 70 mm, representative of gestational ages ranging from 17 to 36 weeks, were scanned with mechanical sector, phased sector, and linear array systems (ATL, Diasonics, Acuson, and GE). Measurements were made with...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198505000-00016
更新日期:1985-05-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To summarize the chemical synthesis, physicochemical characterization, pharmacokinetic behavior, and biological evaluation of P743, a new macromolecular iodinated contrast medium. METHODS:The synthesis and molecular modeling of the iodinated macromolecule P743 are described. The pharmacokineti...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200101000-00006
更新日期:2001-01-01 00:00:00
abstract:RATIONALE AND OBJECTIVE:The authors performed a retrospective study in ultrasound to investigate new aspects in the sonomorphology of lymph node metastases of the neck. In this study, it could be demonstrated the first time that the histologic characteristics of the metastases determine the sonographic appearance. In a...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199609000-00001
更新日期:1996-09-01 00:00:00
abstract::A 144cerium-induced osteosarcoma was transplanted to athymic nude rats (Han:rnu/rnu). Nineteen of the tumor-bearing animals were used to demonstrate the characteristics of the osteosarcoma on magnetic resonance imaging (MRI) in comparison with a group of nine animals that had not received any tumor transplant. The tum...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1992-03-01 00:00:00
abstract:OBJECTIVE:The aim of this study was to evaluate the potential of iterative metal artifact reduction (IMAR) for the improvement of computed tomography (CT)-based position emission tomography (PET) attenuation correction in the vicinity of metal implants and compare it with dual-energy-based metal artifact reduction stra...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000306
更新日期:2017-01-01 00:00:00
abstract:OBJECTIVES:Over the recent years, there have been increasing concerns that exposure to gadolinium-based contrast agents (GBCAs) may be associated with retention of Gd within the skin, bones, and solid organs in patients with normal renal function, although the clinical implications of this deposition remain to be estab...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0000000000000657
更新日期:2020-07-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:The capability of an indirect computed tomographic lymphography (CT-LG) using a nonionic monometric contrast medium iopamidol for visualizing breast lymphatic pathways was preliminarily tested. MATERIALS AND METHODS:In 10 female dogs, a total of 0.5 and 1 mL of undiluted iopamidol was injected...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200302000-00002
更新日期:2003-02-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:Ureteric jet index (UJI), a newly developed technique derived from color Doppler ultrasonography, may hold promise in evaluating renal function because of its ability to evaluate individual renal function and the use of nonionizing radiation. To assess the usefulness of UJI, the authors in this...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199908000-00001
更新日期:1999-08-01 00:00:00
abstract:OBJECTIVES:To prospectively evaluate accuracy of biliary anatomy depiction and quality of biliary tract visualization of magnetic resonance cholangiography (MRC) at 3.0 T in living potential liver donors (LPLDs). MATERIALS AND METHODS:Our institutional review board approved this study and did not require patient's inf...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/RLI.0b013e31817e9b52
更新日期:2008-08-01 00:00:00
abstract::We developed a new, cineangiographic method to accurately measure the dynamic changes in the internal diameter of human arteries in vivo. Cine films were digitized at a spatial resolution of 4 microns/pixel, using a line image sensor. The vessel edges, with a Gaussian fit to a unilateral profile curve of the vessel, w...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198909000-00005
更新日期:1989-09-01 00:00:00
abstract:OBJECTIVES:The authors assessed the relative efficacy of conventional and digital storage-phosphor radiographs for the detection of skull fractures. METHODS:Fifty conventional film-screen radiographs (FSR) and 50 digital storage-phosphor radiographs (DR) with 66 fractures were compared. Five radiologists evaluated ima...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-199308000-00005
更新日期:1993-08-01 00:00:00
abstract::Low-dose transaxial tomography is a technique that can produce cross-sectional images of the hips and femurs in children to permit calculation of the angle of femoral anteversion. Transaxial tomography was compared with computed tomography in terms of measured radiation dose and image quality. Transaxial tomography wa...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:
更新日期:1985-12-01 00:00:00
abstract::Magnetic resonance (MR) methods have been used to study the metabolic and vascular response of model tumors to tumor necrosis factor (TNF). Magnetic resonance measurements demonstrated acute reductions in tumor blood flow, measured from tumor uptake of D2O, and in tumor adenosine triphosphate (ATP), measured by 31P ma...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-198912000-00022
更新日期:1989-12-01 00:00:00
abstract:RATIONALE AND OBJECTIVES:To characterize the long-term effects of therapeutic doses of ionizing radiation on the uptake and distribution of percutaneously delivered particulate contrast media in normal lymph nodes. METHODS:Two milliliters of an iodinated nanoparticle suspension (76 mg I/mL) was injected subcutaneously...
journal_title:Investigative radiology
pub_type: 杂志文章
doi:10.1097/00004424-200003000-00007
更新日期:2000-03-01 00:00:00