Application of 3D T1 Black-Blood Imaging in the Diagnosis of Leptomeningeal Carcinomatosis: Potential Pitfall of Slow-Flowing Blood
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* S.A. Nabavizadeh

I read the publication “Application of 3D Fast Spin-Echo T1 Black-Blood Imaging in the Diagnosis and Prognostic Prediction of Patients with Leptomeningeal Carcinomatosis” by Oh et al1 with a great interest. The authors concluded that black-blood imaging showed a significantly higher sensitivity than contrast-enhanced gradient recalled-echo and contrast-enhanced spin-echo imaging for detecting leptomeningeal carcinomatosis.

A variety of techniques can be used to achieve blood suppression on T1-weighted imaging. The most commonly used technique, which was also used by Oh et al,1 is a variable flip angle refocusing pulse sequence in which the protons in the vessel lumen experience the slice-selective radiofrequency pulse but flow out of the imaging section before the refocusing pulse, resulting in blood-signal suppression. This technique is widely used in high-resolution intracranial vessel wall MR imaging; however, an important pitfall with this technique is that slow-flowing blood in leptomeningeal veins, dilated arteries, or leptomeningeal collaterals can cause incomplete or lack of suppression.2,3 Kato et al4 compared 3D fast spin-echo (sampling perfection with application-optimized contrasts by using different flip angle evolutions [SPACE; Siemens, Erlangen, Germany]) and 3D gradient-echo T1-weighted MPRAGE images in patients with small parenchymal brain metastasis. Lesion detectability was significantly higher on SPACE than on MPRAGE; however, vessels were falsely reported as metastasis using both techniques. I can only imagine that this pitfall will be aggravated when assessing leptomeningeal metastasis. One way to avoid these artifacts would be to use a double inversion recovery technique, which exploits both the flow and T1 properties of blood to suppress its signal.2 This technique requires a longer acquisition time, which is a limitation in high-resolution intracranial vessel wall MR imaging, given the need for very high spatial resolution; however, this should be less of a problem in the context of metastatic disease.

In conclusion, I agree with the authors that postcontrast T1 black-blood imaging is a promising technique for the detection of leptomeningeal carcinomatosis; however, it will require further investigation to determine the best technique for blood suppression to avoid the above-mentioned pitfall.

## References

1.  1. Oh J, Choi SH, Lee E, et al. Application of 3D fast spin-echo T1 black-blood imaging in the diagnosis and prognostic prediction of patients with leptomeningeal carcinomatosis. AJNR Am J Neuroradiol 2018;39:1453–59 doi:10.3174/ajnr.A5721 pmid:30002052
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo5OiIzOS84LzE0NTMiO3M6NDoiYXRvbSI7czoyMToiL2FqbnIvMzkvMTIvRTEyNS5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

2.  2. Mandell DM, Mossa-Basha M, Qiao Y, et al; Vessel Wall Imaging Study Group of the American Society of Neuroradiology. Intracranial vessel wall MRI: principles and expert consensus recommendations of the American Society of Neuroradiology. AJNR Am J Neuroradiol 2017;38:218–29 doi:10.3174/ajnr.A4893 pmid:27469212
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIzOC8yLzIxOCI7czo0OiJhdG9tIjtzOjIxOiIvYWpuci8zOS8xMi9FMTI1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

3.  3. Lindenholz A, van der Kolk AG, Zwanenburg JJ, et al. The use and pitfalls of intracranial vessel wall imaging: how we do it. Radiology 2018;286:12–28 doi:10.1148/radiol.2017162096 pmid:29261469
    
    [CrossRef](http://www.ajnr.org/lookup/external-ref?access_num=10.1148/radiol.2017162096&link_type=DOI) 
    
    [PubMed](http://www.ajnr.org/lookup/external-ref?access_num=29261469&link_type=MED&atom=%2Fajnr%2F39%2F12%2FE125.atom) 

4.  4. Kato Y, Higano S, Tamura H, et al. Usefulness of contrast-enhanced T1-weighted sampling perfection with application-optimized contrasts by using different flip angle evolutions in detection of small brain metastasis at 3T MR imaging: comparison with magnetization-prepared rapid acquisition of gradient echo imaging. AJNR Am J Neuroradiol 2009;30:923–29 doi:10.3174/ajnr.A1506 pmid:19213825
    
    [Abstract/FREE Full Text](http://www.ajnr.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiYWpuciI7czo1OiJyZXNpZCI7czo4OiIzMC81LzkyMyI7czo0OiJhdG9tIjtzOjIxOiIvYWpuci8zOS8xMi9FMTI1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

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