ADC Measurement of Abdominal Organs and Lesions Using Parallel Imaging Technique

Yoshikawa, Takeshi; Kawamitsu, Hideaki; Mitchell, Donald G.; Ohno, Yoshiharu; Ku, Yonson; Seo, Yasushi; Fujii, Masahiko; Sugimura, Kazuro

doi:10.2214/ajr.05.0778

Cited by 283 publications

(242 citation statements)

References 37 publications

Supporting

Mentioning

206

Contrasting

Unclassified

Order By: Relevance

“…SENSE, GRAPPA) to minimize imaging time, thus preserving image signal-to-noise and reducing motion-related artifacts, without signiˆcantly impacting apparent diŠusion coe‹cient (ADC) calculations. 2 Current widely used imaging strategies for DWI in the body include: (1) breath-hold single-shot DWI, (2) non-breath-hold multiple averaging DWI, and (3) non-breath-hold multiple averaging DWI performed at multiple body stations (diŠu-sion-weighted whole-body imaging with background body signal suppression [DWIBS]). Although each of these strategies is suitable for general imaging of the abdomen and pelvis, the selection of imaging sequence may be in‰uenced by the anatomical region being investigated, whether the images are to be analyzed qualitatively or quantitatively, and the size and heterogeneity of lesions evaluated.…”

Section: Dwi Imaging Strategies In the Bodymentioning

confidence: 99%

“…When DWI is performed with increasing bvalues, the attenuation of the signal intensity in abdominal organs has been shown to be biexponential for the range used for clinical imaging in the body (e.g., b＝0 to 1000 s/mm 2 ). An initial rapid decrease in signal intensity with a small increase in b-value is followed by a more gradual slope of signal attenuation as the b-value increases further.…”

Section: Magnetic Resonance In Medical Sciencesmentioning

confidence: 99%

See 1 more Smart Citation

Practical Aspects of Assessing Tumors Using Clinical Diffusion-weighted Imaging in the Body

Koh

Takahara

Imai

et al. 2007

MRMS

190

137

View full text Add to dashboard Cite

DiŠusion-weighted magnetic resonance (MR) imaging (DWI) is increasingly applied to evaluate tumors in the abdomen and pelvis. However, DWI is susceptible to a variety of artifacts that arise from motion, use of strong gradient pulses, and echo-planar imaging technique. We discuss practical issues to help radiologists optimize the use of DWI to evaluate tumors in the body, including breath-hold DWI, multiple-acquisition non-breath-hold DWI, and diŠusion-weighted whole-body imaging with background body signal suppression (DWIBS). Considerations of meticulous technique, sequence optimization, and quality assurance are emphasized for consistent acquisition of high quality images. We illustrate the potential use of these techniques to detect and characterize tumors and to monitor treatment eŠects.

show abstract

Section: Dwi Imaging Strategies In the Bodymentioning

confidence: 99%

Section: Magnetic Resonance In Medical Sciencesmentioning

confidence: 99%

Practical Aspects of Assessing Tumors Using Clinical Diffusion-weighted Imaging in the Body

Koh

Takahara

Imai

et al. 2007

MRMS

190

137

View full text Add to dashboard Cite

show abstract

“…THERE IS A GROWING interest in using liver diffusionweighted imaging (DWI) for lesion detection and characterization, prediction of treatment response and assessment of chronic liver disease, by means of apparent diffusion coefficient (ADC) measurement (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20). The interest in DWI is motivated by the recently described risk of nephrogenic systemic fibrosis (21)(22)(23)(24), which makes DWI an attractive alternate method to Gadolinium-enhanced sequences.…”

mentioning

confidence: 99%

Diffusion‐weighted imaging of the liver: Comparison of navigator triggered and breathhold acquisitions

Taouli

Sandberg

Stemmer

et al. 2009

Magnetic Resonance Imaging

148

122

View full text Add to dashboard Cite

Purpose: To compare a free breathing navigator triggered single shot echoplanar imaging (SS EPI) diffusion-weighted imaging (DWI) sequence with prospective acquisition correction (PACE) with a breathhold (BH) DWI sequence for liver imaging. Materials and Methods:Thirty-four patients were evaluated with PACE-DWI and BH DWI of the liver using bvalues of 0, 50, and 500 s/mm 2 . There were 29 focal liver lesions in 18 patients. Qualitative evaluation was performed on a 3-point scale (1-3) by two independent observers (maximum score 9). Quantitative evaluation included estimated SNR (signal to noise ratio), lesion-to-liver contrast ratio, liver and lesion apparent diffusion coefficients (ADCs), and coefficient of variation (CV) of ADC in liver parenchyma and focal liver lesions (estimate of noise contamination in ADC).Results: PACE-DWI showed significantly better image quality, higher SNR and lesion-to-liver contrast ratio when compared with BH DWI. ADCs of liver and focal lesions with both sequences were significantly correlated (r ϭ 0.838 for liver parenchyma, and 0.904 for lesions, P Ͻ 0.0001), but lower with the BH sequence (P Ͻ 0.02). There was higher noise contamination in ADC measurement obtained with BH DWI (with a significantly higher SD and CV of ADC). Conclusion:The use of a navigator echo to trigger SS EPI DWI improves image quality and liver to lesion contrast, and enables a more precise ADC quantification compared with BH DWI acquisition. THERE IS A GROWING interest in using liver diffusionweighted imaging (DWI) for lesion detection and characterization, prediction of treatment response and assessment of chronic liver disease, by means of apparent diffusion coefficient (ADC) measurement (1-20). The interest in DWI is motivated by the recently described risk of nephrogenic systemic fibrosis (21-24), which makes DWI an attractive alternate method to Gadolinium-enhanced sequences. Most prior studies have used breathhold (BH) single shot echoplanar imaging (SS EPI) to acquire diffusion-weighted images, using various sets of b-values. SS EPI sequences are very fast, however, suffer from limited image quality, mostly related to limited signal to noise ratio (SNR) especially at higher b-values, and limited spatial resolution, which constitute an obstacle for its widespread use in clinical practice. Techniques such as parallel imaging (25,26) and pulse triggering (27) have been proposed to improve SS EPI image quality and precision of ADC measurement.There are several recent reports on the use of respiratory triggered acquisitions for liver DWI (15,16,[28][29][30][31]. However, only two studies have specifically compared different diffusion acquisition schemes for liver imaging (28,30). The first study (28) included a population of patients with liver lesions, and compared image quality and ADC of free breathing versus BH DWI. The second study included healthy volunteers, and compared BH, free breathing and respiratory triggered DWI (without navigator echoes) (30). There are, however, no reports on the use of a...

show abstract

“…The pancreatic head and body have slightly higher ADC values than the tail (69). DWI findings of pancreatic adenocarcinoma suggest that ADC values are lower than in the normal pancreas, although there was considerable variability (70).…”

Section: Abdominal Applicationsmentioning

confidence: 88%

“…Among normal abdominal organs, the highest ADC is found in the kidney, followed by the liver, pancreas, and spleen (69). The ADC values of the upper pole of the kidney are higher than those of the central portion, most likely due to the radial orientation of structures within the kidney, such as renal vessels and tubules (75).…”

Section: Abdominal Applicationsmentioning

confidence: 99%

Diffusion weighted MRI for detecting and monitoring cancer: a review of current applications in body imaging

Türkbey

Aras

Karabulut

et al. 2011

Diagn Interv Radiol

View full text Add to dashboard Cite

Imaging is used to detect, characterize, and monitor cancer. Recently, diffusion-weighted magnetic resonance imaging (DWI) has become a useful adjunct for assessing tumors with magnetic resonance imaging (MRI). DWI involves the acquisition of a magnetic resonance signal related to random thermal motion (Brownian motion) or the "diffusion" of water protons in tissue. The signal obtained with DWI is a measure of the net displacement of water molecules, e.g., the water path length in the extracellular, intracellular and intravascular spaces. This motion is largely random and can be reduced by structural barriers, such as cell membranes and collagen. Restricted diffusion in biological tissues is inversely proportional to tissue cellularity and the integrity of cell membranes, and it can be quantified with apparent diffusion coefficient (ADC) measurements (1). Depending on the microarchitecture, either restricted or increased diffusion can occur in malignant tumors. For instance, diffusion is restricted in cellular portions of the tumor, but it may be increased in necrotic portions (2, 3). Other causes of enhanced diffusion include increased water content arising from intratumoral edema and cystic tumor components (4-6).Although initially used to evaluate neurological diseases, the applications of DWI have been extended to oncologic imaging throughout the body made possible by improvements in MRI hardware and new sequences. The use of DWI as a complement to conventional MRI methods has led to improvements in the detection and characterization of tumors, treatment response monitoring, and detection of recurrence in oncology patients. Basic concepts of DWIIn 1965, Stejskal and Tanner (7) proposed the application of a symmetric pair of additional gradients on either side of the 180˚ refocusing radiofrequency pulse. The Stejskal-Tanner sequence is still the basis of modern DWI. For static water molecules, the phasing effect caused by the first gradient will be reversed by the second gradient, leading to no signal loss; however, this phasing effect will not be completely reversed if the water molecules are not stationary, which results in the observed well-known diffusion signal decay. The amount of diffusion weighting is determined by the b value, which describes the amplitude, duration of the applied gradient, and time interval between the two diffusion gradients (4). The degree of signal attenuation from water molecules is cor- ABSTRACT Diffusion-weighted magnetic resonance imaging (MRI), which involves the acquisition of a magnetic resonance signal related to the Brownian motion of water protons in tissue, has become a useful technique for assessing tumors. In this article, we review the basic concepts, imaging strategies, and body applications of diffusion-weighted MRI in detecting and monitoring cancer.

show abstract

ADC Measurement of Abdominal Organs and Lesions Using Parallel Imaging Technique

Abstract: Clinical ADC measurements of abdominal organs and lesions using parallel imaging appear to be reliable and useful, and the effect of parallel imaging on calculated values is considered to be minimal.

Cited by 283 publications

References 37 publications

Practical Aspects of Assessing Tumors Using Clinical Diffusion-weighted Imaging in the Body

Practical Aspects of Assessing Tumors Using Clinical Diffusion-weighted Imaging in the Body

Diffusion‐weighted imaging of the liver: Comparison of navigator triggered and breathhold acquisitions

Diffusion weighted MRI for detecting and monitoring cancer: a review of current applications in body imaging

Contact Info

Product

Resources

About