Subtraction images: A really helpful tool in non-vascular MRI

Eid, Mohamed; Abougabal, Ahmed Mohamed

doi:10.1016/j.ejrnm.2014.04.013

Cited by 10 publications

(7 citation statements)

References 8 publications

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“…The treatment zone exhibits hyperintense T1 signal on pre-contrast images, which makes the assessment of tumor enhancement difficult on the dynamic contrast-enhanced T1WI [13]. Subtraction imaging is an available technique whereby an unenhanced T1-weighted image is digitally subtracted from the identical image performed after contrast administration aiming to remove any native T1 signal from the images and the remaining signal on the subtracted images is solely due to enhancement [8].…”

Section: Discussionmentioning

confidence: 99%

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The value of dynamic subtraction MRI technique in the assessment of treatment response of hepatocellular carcinoma to transcatheter arterial chemoembolization

Metwally

Mahmoud

Yehia

2019

Egypt J Radiol Nucl Med

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Background: Hepatocellular carcinoma is considered to be the fifth most common cancer worldwide. Resection and liver transplantation have a high survival in the correct clinical scenarios; however, locoregional therapy has many advantages over tumor resection like preservation of hepatic parenchyma and overall less morbidity and mortality. Our aim was to present the role of dynamic subtraction MRI technique in the assessment of treatment response of hepatocellular carcinoma to transarterial chemoembolization. Methods: The study consisted of 43 patients with 55 hepatocellular carcinoma lesions who underwent transarterial chemoembolization procedure and followed up by dynamic MRI of the liver with post processing to obtain subtraction images 1-1.5 months after the procedure. If no signs of disease activity, another follow up study was preformed 2-4 months later. Five patients were excluded due to misregistration artifact at the subtraction images. The final cohort is 38 patients having 50 lesions. Precontrast T1, T2, dynamic contrast enhanced, and diffusion-weighted images were acquired. Subtracted dynamic images were created on the workstation. Sequences were assessed by three experienced readers in hepatic imaging. The sensitivity, specificity, positive predictive value, negative predictive value, 95% confidence interval, and overall agreement were calculated for the dynamic and subtracted dynamic images.Results: The subtraction images have sensitivity of 96%, specificity of 100%, PPV of 100%, and NPV of 100% Compared to 96%, 100%, 100%, 96%, and 96%, 100%, 100% 96% for the three readers respectively. On the other hand, the dynamic images has sensitivity of 92%, specificity of 96%, PPV of 95%, and NPV of 92.3% compared to 92%, 96%, 95%, 92.3% and 80%, 68%, 71.4%, and 77.2% for the three readers respectively.Conclusion: Subtraction technique is a useful confirmative tool as it had higher sensitivity, specificity, PPV, and NPV values compared to the dynamic and diffusion images with high level of agreement between the readers and also associated with significantly higher reader confidence levels.

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Section: Discussionmentioning

confidence: 99%

“…There are many applications for this technique including evaluation of complicated cysts, hemorrhagic masses, and other settings in which determining the presence or absence of enhancement is critical. Subtraction imaging can make evaluation of such lesions more straight forward [8].…”

Section: Introductionmentioning

confidence: 99%

The value of dynamic subtraction MRI technique in the assessment of treatment response of hepatocellular carcinoma to transcatheter arterial chemoembolization

Metwally

Mahmoud

Yehia

2019

Egypt J Radiol Nucl Med

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“…After subtraction, native T1 signals disappear, and the remaining signals are due solely to the enhancement associated with shortening of the T1 relaxation time owing to the intravenous contrast administration or flow effect [13,14]. This technique is widely used, and determining the presence/absence of enhancement is critical [15]. Therefore, the purpose of the present study was to evaluate the usefulness of a standardization map of pelvic MRI for patients with ovarian endometriosis.…”

Section: Introductionmentioning

confidence: 99%

Usefulness of subtraction pelvic magnetic resonance imaging for detection of ovarian endometriosis

Lee

2020

Yeungnam Univ J Med

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Background: To minimize damage to the ovarian reserve, it is necessary to evaluate the follicular density in the ovarian tissue surrounding endometriosis on preoperative imaging. The purpose of the present study was to evaluate the usefulness of subtraction pelvic magnetic resonance imaging (MRI) to detect ovarian reserve. Methods: A subtracted T1-weighted image ( sub T1WI) was obtained by subtracting unenhanced T1WI from contrast-enhanced T1WI ( ce T1WI) with similar parameters in 22 patients with ovarian endometriosis. The signal-to-noise ratio (SNR) in ovarian endometriosis, which was classified into the high signal intensity and iso-to-low signal intensity groups on the T2-weighted image, was compared to that in normal ovarian tissue. To evaluate the effect of contrast enhancement, a standardization map was obtained by dividing sub T1WI by ce T1WI. Results: On visual assessment of 22 patients with ovarian endometriosis, 16 patients showed a high signal intensity, and 6 patients showed an iso-to-low signal intensity on T1WI. Although SNR in endometriosis with a high signal intensity was higher than that with an iso-to-low signal intensity, there was no difference in SNR after the subtraction (13.72±77.55 vs. 63.03±43.90, p=0.126). The area of the affected ovary was smaller than that of the normal ovary (121.10±22.48 vs. 380.51±75.87 mm 2 , p=0.002), but the mean number of pixels in the viable remaining tissue of the affected ovary was similar to that of the normal ovary (0.53±0.09 vs. 0.47±0.09, p=0.682). Conclusion: The subtraction technique used with pelvic MRI could reveal the extent of endometrial invasion of the normal ovarian tissue and viable remnant ovarian tissue.

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“…Subtraction imaging utilizes fat saturated T1 non-contrast and fat saturated T1 post gadolinium contrast sequences using identical imaging criteria. Another image series is created using digital subtraction technique and hence remaining signal in subtraction is merely attributed to enhancement (3,4). It is particularly helpful if the deep infiltrating endometriotic lesion is adjacent to or within the hemorrhagic or proteinaceous fluid in cul-de-sac where T1 imaging shows hyperintensity regardless of gadolinium contrast, thus subtraction sequence solely shows enhancing foci of endometriosis, clinching the diagnosis (3).…”

mentioning

confidence: 99%

“…It is particularly helpful if the deep infiltrating endometriotic lesion is adjacent to or within the hemorrhagic or proteinaceous fluid in cul-de-sac where T1 imaging shows hyperintensity regardless of gadolinium contrast, thus subtraction sequence solely shows enhancing foci of endometriosis, clinching the diagnosis (3). This feature of subtraction imaging is moreover valuable in DIE where lesion itself is hyperintense to muscle in T1 noncontrast sequences and qualitative evaluation of contrast enhancement is challenging in contrast enhanced T1 fat saturated sequence (1,2,4). We came across a 36-year-old female with pelvic pain and a clinical diagnosis related to endometriosis.…”

mentioning

confidence: 99%