تحليل صور موتر الانتشار على طول الفضاء المحيط بالأوعية (DTI-ALPS): إعادة النظر في معنى وأهمية الطريقة

مقدمة

الشكل 1 مفهوم طريقة DTI-ALPS. الاتجاه المفترض لنقل الكتلة داخل نسيج الدماغ موضح في (أ). لكي تصل المواد النفايات إلى الأوردة الدماغية السطحية أو الأوردة تحت البطينية، يجب أن تسير في -الاتجاه، المشار إليه بالسهم الأحمر. في نسيج الدماغ الفعلي، تسير الأوعية النخاعية أيضًا في هذا -الاتجاه. تُظهر العلاقة الموضعية بين اتجاه جري الألياف الرئيسية في المادة البيضاء خارج البطينات الجانبية وموقع الأوعية النخاعية والمساحة المحيطة بالأوعية في و . في هذا الموقع، تكون الألياف الإسقاطية والأوعية النخاعية والألياف الترابطية والأوعية النخاعية في وضع عمودي على بعضها البعض. وهذا يجعل من الممكن تقييم مكون الانتشار في اتجاه الأوعية النخاعية من خلال القضاء على تأثير المكون القوي للانتشار للألياف الإسقاطية والترابطية. يتم عرض صيغة مؤشر ALPS في يتم استخدام نسبة مكون الانتشار العمودي على كل من ألياف الإسقاط والأوعية النخاعية ومكون الانتشار العمودي على كل من ألياف الارتباط والأوعية النخاعية كمرجع داخلي لتقييم مكون الانتشار في اتجاه الأوعية النخاعية. تُظهر الصورة الخاصة بمصفوفة الانتشار الإهليلجية. تتوافق المحاور الرئيسية للكرة البيضوية مع ألياف الإسقاط (باللون الأزرق) وألياف الارتباط (باللون الأخضر)، على التوالي. البيضاوي الصغير في هو صورة لمؤشر ALPS. البيضاوي الكبير في -الاتجاه يتوافق مع مؤشر ALPS كبير، كما هو موضح في f. تحليل صورة الموتر الانتشاري على طول الفضاء المحيط بالأوعية.

مفهوم DTI-ALPS

تطبيق DTI-ALPS

طلب لمرض الزهايمر

الشكل 2 تطبيق طريقة ALPS في مرض الزهايمر. يتم عرض مخططات الكمان والصندوق لمتوسط مؤشر ALPS، PVSVF-ALL، PVSVF-WM، PVSVF-BG، PVSVFHipp، وFW-WM بين المشاركين الأصحاء، والمرضى الذين يعانون من ضعف إدراكي معتدل، والمرضى الذين يعانون من مرض الزهايمر. مقارنةً بالمشاركين الأصحاء، كان لدى مرضى الزهايمر إجمالي PVSVF، WM، BG PVSVF أعلى بشكل ملحوظ (Cohen ) و FW-WM ( كوهين ) ومؤشر ALPS المنخفض (كوهين ). كانت مجموعة MCI لديها إجمالي PVSVF أعلى بشكل ملحوظ (Cohen ) و WM ( كوهين . الشكل مقتبس من المرجع 20. AD، مرض الزهايمر؛ PVSVF، نسبة حجم الفضاء المحيط بالأوعية؛ WM، المادة البيضاء؛ BG، العقد القاعدية؛ FW، الماء الحر؛ HC، مجموعة التحكم الصحية؛ MCI، ضعف إدراكي خفيف.

طلب لمرض باركنسون وأمراض التنكس الأخرى

الشكل 3 تطبيق طريقة ALPS في مرض باركنسون. تم مقارنة الفروق في مؤشر ALPS بين مجموعة مرض باركنسون ومجموعة الشهود الأصحاء وبين مجموعتي مرض باركنسون ومجموعة الشهود الأصحاء. تم عرض العلاقات بين مؤشر ALPS ودرجة MMSE في مجموعة مرض باركنسون المبكر (A)، والعلاقات بين مؤشر ALPS ودرجة EPVS في مجموعة مرض باركنسون المبكر (B) والعلاقات بين مؤشر ALPS والعمر في مجموعة مرض باركنسون المتأخر (C). كان هناك ارتباط إيجابي كبير بين مؤشر ALPS ودرجة MMSE. ) ( ) ، وارتباط سلبي بين مؤشر ALPS ودرجة EPVS ( ). مؤشر ALPS مرتبط سلبًا بالعمر ( ). الشكل مقتبس من المرجع 184. PD، مرض باركنسون؛ NC، التحكم الطبيعي؛ MMSE، اختبار الحالة العقلية المصغر؛ EPVS، الفضاء المحيط بالأوعية الدموية المتضخم.

طلب لأمراض الأوعية الدموية الصغيرة

طلب لفرط الضغط الدماغي الطبيعي مجهول السبب

تطبيق لإصابة الدماغ الرضحية

تطبيق لمرض إزالة الميالين

الشكل 4 تطبيق طريقة ALPS في iNPH. تم تقديم دراسة حول التغيرات في مؤشر ALPS بعد جراحة LPS في iNPH، مقارنة بين المرضى الذين استجابوا لـ LPS والذين لم يستجيبوا. كان متوسط مؤشر ALPS في المجموعة بعد الجراحة أعلى بشكل ملحوظ من المجموعة قبل الجراحة (A). علاوة على ذلك، بالنسبة للمواضيع المستجيبة، كان متوسط مؤشر ALPS في المجموعة بعد الجراحة أعلى بشكل ملحوظ من المجموعة قبل الجراحة (B). من ناحية أخرى، في مجموعة غير المستجيبين، لم يكن متوسط مؤشر ALPS في المجموعة بعد الجراحة أعلى بشكل ملحوظ من المجموعة قبل الجراحة (C). لم تكن مؤشرات ALPS في مجموعة المستجيبين مختلفة بشكل ملحوظ مقارنة بتلك الخاصة بمجموعة غير المستجيبين في كل من مجموعات ما قبل العملية وما بعد العملية (D). الشكل مقتبس من المرجع 62. iNPH، استسقاء الدماغ ذو الضغط الطبيعي مجهول السبب؛ LPS، تحويلة لامبوسبيريتونيال.

تطبيق للنوم

الشكل 5 اعتماد مؤشر ALPS على وقت اليوم. تم تقييم اعتماد إيقاع الساعة البيولوجية لمؤشر ALPS من خلال قياسات MRI المتكررة في خمس نقاط زمنية من 8:00 إلى 23:00. تم إجراء تصوير الانتشار بتقنية DTI-ALPS منخفضة التشتت، والذي يقيس تدفق SAS على طول الشريان الدماغي الأوسط، وDTI-ALPS التقليدي. تظهر A وB مسار تدفق النظام الغليمفاتي المدخل والمخرج المقاس بواسطة DTI-ALPS وDTI-ALPS، على التوالي. لم يختلف ADlow-b لسائل SAS في MCA ولا مؤشر ALPS بشكل ملحوظ في البيانات المكتسبة في النقاط الزمنية الخمس. الشكل مقتبس من المرجع 159. MRI، التصوير بالرنين المغناطيسي؛ DTI، صورة الانتشار؛ SAS، الفضاء تحت العنكبوتي؛ DTI-ALPS، تحليل صورة الانتشار على طول الفضاء المحيط بالأوعية؛ AD، مرض الزهايمر؛ MCA، الشريان الدماغي الأوسط.

النتائج حول الشيخوخة

طرق أخرى لتقييم النظام اللمفاوي الدماغي

GBCA داخل السائل النخاعي

GBCA عن طريق الوريد

حجم الفضاء المحيط بالأوعية الدموية

حجم المشيمية الوعائية

طرق الانتشار بخلاف طريقة ALPS

توسيم الدوران الشرياني

تصوير حركيات أنسجة الدماغ

طرق أخرى لدراسة المتتبعين

اعتبار منهجية DTI-ALPS

وضع العائد على الاستثمار

إمكانية إعادة إنتاج طريقة ALPS

الشكل 6 وضع منطقة الاهتمام (ROI) لطريقة ALPS. النقطة الأكثر أهمية في وضع منطقة الاهتمام هي التأكد من قياس جميع مجموعات الحالات بشكل موحد. من المهم أيضًا التأكد من أن الألياف الإسقاطية والارتباطية عمودية على -المحور. بشكل خاص، عند تحديد منطقة الاهتمام في منطقة ألياف الارتباط، يجب توخي الحذر لتجنب خلط الألياف تحت القشرية التي يكون محورها الرئيسي في الـ -الاتجاه. إذا تم تضمين الألياف تحت القشرية، سيكون مؤشر ALPS أعلى مما ينبغي. بعد ذلك، هناك طرق مختلفة لوضع مناطق الاهتمام: فقط على الجانب الأيسر من نصف الكرة الدماغي المسيطر (أ)، التوظيف الثنائي (ب)، التوزيع القائم على الأطلس (ج) والمكانة مع التحويل إلى الدماغ القياسي (د).

تعديل طريقة ALPS

الجدل في طريقة DTI-ALPS

الخاتمة

تعارض المصالح

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Diffusion Tensor Image Analysis ALong the Perivascular Space (DTI-ALPS): Revisiting the Meaning and Significance of the Method

Introduction

Fig. 1 Concept of DTI-ALPS method. The assumed direction of mass transport within the brain parenchyma is shown in a. For waste material to reach the superficial cerebral veins or the subependymal veins, it must travel in the -direction, indicated by the red arrow. In actual brain tissue, the medullary vessels also run in this -direction. The positional relationship between the running direction of major fibers in the white matter outside the lateral ventricles and the location of the medullary vessels and perivascular space is shown in and . At this location, projection fibers and medullary vessels and association fibers and medullary vessels are in an orthogonal position to each other. This makes it possible to evaluate the diffusion component in the direction of the medullary vessels by eliminating the influence of the strong diffusion component of the projection and association fibers. The formula for the ALPS-index is shown in . The ratio of the diffusion component perpendicular to both the projection fiber and the medullary vessels and the diffusion component perpendicular to both the association fiber and the medullary vessels is employed as an internal reference to evaluate the diffusion component in the direction of the medullary vessels. The image of the diffusion tensor ellipsoid is shown in . The major axes of the ellipsoid correspond to projection fibers (blue) and association fibers (green), respectively. The small oval in is the image of the ALPS-index. The oval that is large in the -direction corresponds to a large ALPS-index, as shown in f. DTI-ALPS, Diffusion Tensor Image Analysis aLong the Perivascular Space.

Concept of DTI-ALPS

Application of DTI-ALPS

Application for Alzheimer’s disease

Fig. 2 Application of ALPS method in AD. Violin and box plots of the mean ALPS-index, PVSVF-ALL, PVSVF-WM, PVSVF-BG, PVSVFHipp, and FW-WM among the HC participants, patients with MCI, and patients with AD are shown. Compared to HC, AD patients had significantly higher total PVSVF, WM, BG PVSVF (Cohen ) and FW-WM (Cohen ) and lower ALPS-index (Cohen ). The MCI group had significantly higher total PVSVF (Cohen ) and WM (Cohen . Figure quoted from Ref. 20. AD, Alzheimer’s disease; PVSVF, perivascular space volume fraction; WM, white matter; BG, basal ganglia; FW, free water; HC, healthy control; MCI, mild cognitive impairment.

Application for Parkinson’s disease and other degenerative disease

Fig. 3 Application of ALPS method in PD. Differences in ALPS-index between the PD group and NCs and between two PD subgroups and NCs were compared. Relationships between ALPS-index and MMSE score in early PD group (A), relationships between ALPS-index and EPVS score in early PD group (B) and relationships between ALPS-index and age in late PD group (C) are shown. There was a significant positive correlation between ALPS-index and MMSE score ( ) ( ), and a negative correlation between ALPS-index and EPVS score ( ). ALPS-index negatively related with age ( ). Figure quoted from Ref. 184. PD, Parkinson’s disease; NC, normal control; MMSE, Mini-Mental State Examination; EPVS, enlarged perivascular space.

Application for small vessel diseases

Application for idiopathic normal pressure hydrocephalus

Application for traumatic brain injury

Application for demyelinating disease

Fig. 4 Application of ALPS method in iNPH. A study of changes in ALPS-index after LPS surgery in iNPH is presented, comparing patients who responded to LPS with those who did not. The mean ALPS-index of the postoperative group was significantly higher than that of the preoperative group (A). Furthermore, for responding subjects, the mean ALPS-index in the postoperative group was significantly higher than in the preoperative group (B). On the other hand, in the non-responder group, the mean ALPS-index of the postoperative group was not significantly higher than that of the preoperative group (C). The mean ALPS indices of the responder group were not significantly different compared to those of the non-responder group in both the pre-operation and post-operation groups (D). Figure quoted from Ref. 62. iNPH, idiopathic normal pressure hydrocephalus; LPS, lumboperitoneal shunt.

Application for sleep

Fig. 5 Time-of-day dependency of ALPS-index. Circadian rhythm dependence of ALPS-index was assessed by repeated MRI measurements at five time points from 8:00 to 23:00. Very long echo-time low-b diffusion tensor imaging (DTIlow-b), which measures SAS flow along the middle cerebral artery, and conventional DTI-ALPS were performed. A, B show the time course of the glymphatic system influx and efflux measured by DTIlow-b and DTI-ALPS, respectively. Neither ADlow-b of the MCA SAS fluid nor the ALPS-index differed significantly in the data acquired at the five time points. Figure quoted from Ref. 159. MRI, magnetic resonance imaging; DTI, Diffusion Tensor Image; SAS, subarachnoid space; DTI-ALPS, Diffusion Tensor Image Analysis aLong the Perivascular Space; AD, Alzheimer’s disease; MCA, middle cerebral artery.

Findings on the aging

Other Methods for Evaluation of Glymphatic System

Intrathecal GBCA

Intravenous GBCA

Perivascular space volume

Choroid plexus volume

Diffusion-based methods other than ALPS method

Arterial spin labeling

Imaging for brain tissue kinetics

Other tracer study methods