Coil Sensitivity Encoding in MR Imaging

Kurihara, Yasuyuki; Yakushiji, Yoshiko K.; Tani, I; Nakajima, Yasuo; Cauteren, Marc Van

doi:10.2214/ajr.178.5.1781087

Cited by 51 publications

(5 citation statements)

References 4 publications

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“…Nevertheless, up to 60% of small malignant nodules, particularly those less than 1 cm size in the background of cirrhotic liver, are missed at MRI [19]. Continued improvement in the MR sequences and hardware [20, 21], as well as the advent of liver-specific contrast agents [22, 23], which are only available for MRI, have led to the improved diagnostic performance of MRI. The broad arsenal of MR sequences and multiphasic postcontrast imaging provide comprehensive information on the liver lesion by elucidating different signal intensities that reflect the inherent properties of the lesion's composition, as well as blood flow dynamics, which gives each lesion type different MR characteristic appearances.…”

Section: The Evolution In Magnetic Resonance Imaging (Mri) Of the mentioning

confidence: 99%

Gadoxetate Acid-Enhanced MR Imaging for HCC: A Review for Clinicians

Chanyaputhipong

Low

Chow

2011

International Journal of Hepatology

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Hepatocellular carcinoma (HCC) is increasingly being detected at an earlier stage, owing to the screening programs and regular imaging follow-up in high-risk populations. Small HCCs still pose diagnostic challenges on imaging due to decreased sensitivity and increased frequency of atypical features. Differentiating early HCC from premalignant or benign nodules is important as management differs and has implications on both the quality of life and the overall survival for the patients. Gadoxetate acid (Gd-EOB-DTPA, Primovist®, Bayer Schering Pharma) is a relatively new, safe and well-tolerated liver-specific contrast agent for magnetic resonance (MR) imaging of the liver that has combined perfusion- and hepatocyte-specific properties, allowing for the acquisition of both dynamic and hepatobiliary phase images. Its high biliary uptake and excretion improves lesion detection and characterization by increasing liver-to-lesion conspicuity in the added hepatobiliary phase imaging. To date, gadoxetate acid-enhanced MRI has been mostly shown to be superior to unenhanced MRI, computed tomography, and other types of contrast agents in the detection and characterization of liver lesions. This review article focuses on the evolving role of gadoxetate acid in the characterization of HCC, differentiating it from other mimickers of HCC.

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Section: The Evolution In Magnetic Resonance Imaging (Mri) Of the mentioning

confidence: 99%

Gadoxetate Acid-Enhanced MR Imaging for HCC: A Review for Clinicians

Chanyaputhipong

Low

Chow

2011

International Journal of Hepatology

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“…The SNR in the SENSE-implemented sequence depends on acceleration and geometric factors. The latter vary over the image and describe local noise enhancements on the final reconstructed image; the background noise at parallel imaging thus varies with the spatial position (Pruessmann et al 1999 ; Kurihara et al 2002 ). Therefore we did not perform SNR calculations in a traditional way because of their unambiguous definition is difficult.…”

Section: Methodsmentioning

confidence: 99%

Efficacy of the projection onto convex sets (POCS) algorithm at Gd-EOB-DTPA-enhanced hepatobiliary-phase hepatic MRI

et al. 2016

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PurposeTo investigate the efficacy of the projection onto convex sets (POCS) algorithm at Gd-EOB-DTPA-enhanced hepatobiliary-phase MRI.MethodsIn phantom study, we scanned a phantom and obtained images by conventional means (P1 images), by partial-Fourier image reconstruction (PF, P2 images) and by PF with the POCS algorithm (P3 images). Then we acquired and compared subtraction images (P2–P1 images and P3–P1 images). In clinical study, 55 consecutive patients underwent Gd-EOB-DTPA (EOB)-enhanced 3D hepatobiliary-phase MRI on a 1.5T scanner. Images were obtained using conventional method (C1 images), PF (C2 images), and PF with POCS (C3 images). The acquisition time was 17-, 14-, and 14 s for protocols C1, C2 and C3, respectively. Two radiologists assigned grades for hepatic vessel sharpness and we compared the visual grading among the 3 protocols. And one radiologist compared signal-to-noise-ratio (SNR) of the hepatic parenchyma.ResultsIn phantom study, there was no difference in signal intensity on a peripheral phantom column on P3–P1 images. In clinical study, there was no significant difference between C1 and C3 images (2.62 ± 0.49 vs. 2.58 ± 0.49, p = 0.70) in the score assigned for vessel sharpness nor in SNR (13.3 ± 2.67 vs. 13.1 ± 2.51, p = 0.18).ConclusionThe POCS algorithm makes it possible to reduce the scan time of hepatobiliary phase (from 17 to 14 s) without reducing SNR and without increasing artifacts.

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“…Paralel inceleme yöntemi ile K alanındaki faz kodlama basamak sayısı azaltılarak inceleme zamanında belirgin derecede azalma sağlanır. 5,10 Faz kodlama basamak sayısının azalması SEN-SE redüksiyon faktörü (R) tarafından sağlanır. Örneğin R=2 seçildiğinde K aralığında mevcut olan faz kodlama basamaklarının yarısı kodlanır.…”

Section: Bulgularunclassified

“…Faz tarayıcı koillerde izlenen, koiller arası intensite farklılıkları SENSE tekniğinin kullanımı ile homojen hale getirilmekte ve görüntü kalitesi belirgin artırılmaktadır. 5 Bu çalışmada malign veya benign karaciğer lezyonu olduğu bilinen veya düşünülen hastalarda çok hızlı T2A (SENSE T2A), TSE T2A ve dinamik kontrastlı T1A MRG yöntemleri kullanılarak, lezyon saptama ve karakterize etmedeki duyarlılıklarının karşılaştırılması amaçlanmaktadır. 6 aylık takip sonrası hemanjiom tanısı kondu.…”

Section: Introductionunclassified

Comparison of T2-SENSE, Turbo Spin Echo T2-and T1-weighted MR Sequences for Detection of Liver Lesions

Değirmenci¹,

Çalışkan²,

Kara³

2011

Sakarya Med J

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ÖzetAmaç: Bu çalışmada karaciğer kitlelerinin saptanmasında çok hızlı sensitivity encoding (SENSE) T2 ağırlıklı (T2A), turbo spin eko (TSE) T2A ve T1 ağırlıklı (T1A), manyetik rezonans görüntüleme (MRG) sekanslarının karşılaştırılması amaçlanmaktadır. Gereç ve Yöntem: Bilinen karaciğer kitlesi olan veya yeni tespit edilen toplam 30 hasta çalışmamıza dahil edildi. Tüm hastalara solunum tetiklemeli SENSE T2A, yağ baskılı, selective presaturation invertion recovery (SPIR) SENSE T2A, nefes tutmalı TSE T2A ve nefes tutmalı dinamik kontrastlı 3 boyutlu (3B) T1 fast field echo (FFE) sekansları uygulandı. Saptanan kitlelerin, sayı, boyut, kenar ve sinyal özellikleri değerlendirilip buna göre gruplar oluşturuldu. T2A sekanslarda lezyonlar kenar özelliklerine göre silik ve keskin konturlu, sinyal özelliklerine göre ise hafif, orta ve belirgin hiperintens olarak gruplara ayrıldı. T2A sekanslarda elde edilen lezyon sayıları, T1A sekanslarda elde edilen lezyon sayıları ile karşılaş-tırıldı. Ayrıca T2A sekanslar arasında lezyon sayı ve boyutları açısından karşılaştırma yapıldı. Bulgular: Çalışmamızda yağ baskılı SENSE T2A (SPIR SENSE) sekansta lezyon sayısı en fazla bulundu. Ancak lezyon saptama duyarlılığı açısından istatistiksel olarak T2A sekanslar ile T1A sekanslar arasında anlamlı fark bulunmadı. SPIR SENSE T2A, SENSE T2A ve TSE T2A sekansları arasın-da lezyon boyutu açısından anlamlı istatistiksel fark bulunmadı. Kontur ve sinyal özelliklerine göre yapılan karşılaştırmada T2A sekanslar arasında istatistiksel fark saptanmadı. Sonuç: SENSE T2A çok hızlı sekanslar, özellikle yağ baskılama ile birlikte kullanıldıklarında, karaciğer lezyonlarını saptamada, TSE T2A sekans kadar duyarlıdır. Çok hızlı SENSE T2A sekanslar, TSE T2A sekansların yerine karaciğer görüntülenmesinde kullanılabilecek güvenilir sekanslardır. AbstractObjective: This study aimed to compare ultrafast sensitivity encoding (SENSE) T2-weighted (T2W), turbo spin echo (TSE) T2-W and T1-weighted (T1W) sequences of magnetic resonance imaging (MRI) for detection of liver masses. Materials and Methods: A total of 30 patients with a known or newly detected liver mass were included in the study. All patients underwent respiratory-triggered T2-W SENSE, fat suppressed (SPIR) T2-W SEN-SE, breath-hold TSE T2-weighted and breath-hold dynamic contrastenhanced 3-dimensional (3D) T1-FFE sequences. The detected masses were evaluated for size, margins and signal characteristics, and accordingly the groups were formed. Lesions on T2-W sequences divided into distinct groups as soft and sharp contours according to their edges, and light, medium and hyperintense according to the characteristics of the signal. The number of lesions on T2-W sequences was compared with that on T1-weighted sequences. In addition, the number and size of lesions among T2-weighted sequences were compared. Results: The maximum number of lesions was found in SENSE T2-W fat suppressed (SPIR SENSE) sequences. However, in terms of lesion detection sensitivity, no statistically significant difference was foun...

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Coil Sensitivity Encoding in MR Imaging

Cited by 51 publications

References 4 publications

Gadoxetate Acid-Enhanced MR Imaging for HCC: A Review for Clinicians

Gadoxetate Acid-Enhanced MR Imaging for HCC: A Review for Clinicians

Efficacy of the projection onto convex sets (POCS) algorithm at Gd-EOB-DTPA-enhanced hepatobiliary-phase hepatic MRI

Comparison of T2-SENSE, Turbo Spin Echo T2-and T1-weighted MR Sequences for Detection of Liver Lesions

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