{ "id": 591648, "title": "Overview of the clinical problem", "url": "/competitions/rsna-intracranial-aneurysm-detection/discussion/591648", "author_name": "Maria Correia de Verdier", "post_date": "2025-07-29T17:29:08.734000", "votes": 90, "comment_count": 13, "views": 0, "content": "

Overview of the clinical problem

\n

Intracranial aneurysms (also called ”cerebral” or “brain” aneurysms) are a localized abnormal dilation of an intracranial artery. Aneurysms come in many shapes, but “saccular” aneurysms (also called “berry” aneurysms) are the most common form. Macroscopically, saccular aneurysms are rounded lobulated focal outpouchings, usually arising at arterial bifurcations.
\n\"\"
\nFrom Wikipedia

\n

Intracranial aneurysms affect an estimated ~3% of the global population, and in 15-30% of these patients, multiple aneurysms are found. Alarmingly, up to 50% are first identified only after aneurysm rupture, which is a life threatening event. Saccular aneurysms are true aneurysms, meaning the vessel wall is thinned and weakened. Because the wall is thin and weak, and due to the pressure inside the vessel, aneurysms often expand over time. This growth increases the risk of rupture which leads to subarachnoid hemorrhage–a type of stroke caused by bleeding into the subarachnoid space of the brain. A ruptured intracranial aneurysm is the most common cause of non-traumatic subarachnoid hemorrhage. Subarachnoid hemorrhage accounts for 3% of stroke and 5% of stroke deaths. Typical symptoms of brain aneurysm rupture include a severe “thunderclap” headache, often followed by reduced consciousness, and death if left untreated. Intracranial aneurysms are most often asymptomatic until rupture, however occasionally larger aneurysms will result in symptoms before rupture by, for example, pressing on adjacent nerves.

\n

Intracranial aneurysms can be challenging to detect given that they are often small and asymptomatic, however, even small aneurysms pose a risk of rupture leading to hemorrhage and substantial patient morbidity and even death. When detected, aneurysms can often be treated with minimally-invasive procedures that may be life-saving. Large or symptomatic aneurysms are typically managed through endovascular coiling or surgical clipping. The management of small aneurysms remains controversial, but early detection allows for careful monitoring and timely intervention, reducing the risk of rupture.

\n

This challenge primarily focuses on identifying saccular aneurysms. There are also other types of aneurysms including fusiform aneurysms and pseudoaneurysms, which will not be considered as aneurysms for this challenge given their different imaging appearance and risk profile. The task includes both aneurysm detection and localization, because aneurysms may be located anywhere in the brain.

\n

Anatomical Overview

\n

The brain's arterial supply is divided into anterior and posterior circulations. The anterior circulation is primarily supplied by the internal carotid arteries (ICAs), while the posterior circulation comes from the vertebral arteries (VA) and the basilar artery (BA) that is formed where the right and left VA join after entering the skull. The major branches of the posterior circulation include paired posterior inferior cerebellar arteries (PICAs), anterior inferior cerebellar arteries (AICAs), superior cerebellar arteries (SCAs), and posterior cerebral arteries (PCAs). For this challenge, the posterior circulation will be divided into two anatomical locations: the distal end of the BA (referred to as the basilar tip), and the rest of the posterior circulation. The ICA has several different segments after entering the skull. An important anatomical landmark is where the ICA enters the dura (a fibrous covering of the brain) and after which a potential aneurysm rupture will result in subarachnoid hemorrhage. The clinical significance of this anatomic landmark is the reason that the ICA is divided into supraclinoid and infraclinoid ICA for this challenge. The major branches of the ICA include paired middle cerebral arteries (MCAs) and anterior cerebral arteries (ACAs).

\n

The ICAs and the BAs communicate at the base of the brain via the circle of Willis, a circular connection of arteries that helps maintain blood flow even if one vessel is compromised. The circle of Willis is formed from parts of the bilateral ACAs and PCAs linked via the anterior communicating artery (ACom) and paired posterior communicating arteries (Pcoms). The ACom arises from the ACA and acts as an anastomosis between the left and right anterior cerebral circulation. The PCom connects the anterior circulation (ICAs) to the posterior circulation (PCAs). This description pertains to the most common configuration of the circle of Willis; however, there are many described normal variants with slightly different connections.
\n \"\"
\nFrom Radiopaedia, Case courtesy of Sachi Hapugoda

\n

You will need to predict the presence or absence of aneurysms in the following 13 anatomical locations for each imaging series:
\n \"\"

\n

Imaging Overview

\n

Aneurysms can be identified with a variety of imaging modalities:

\n\n

Each method has its own advantages and limitations. However, DSA, particularly with 3D acquisitions, is generally considered the “gold standard” because of its high spatial and temporal resolution.

\n

CT angiography (CTA) is a non-invasive technique that enables visualization of the blood vessels. It offers several advantages over DSA, including the ability to also assess non-vascular tissues, such as the brain tissue. Additionally, it is less expensive, faster, and presents a lower risk to the patient because it does not require insertion of a catheter into the cerebral arteries. Despite its benefits, CTA has a few limitations compared to DSA. It cannot selectively image individual vessels, and because it images the vessels at a single time point, it limits the evaluation of flow-related features. CTA also has a lower spatial resolution, making it more difficult to detect small aneurysms.

\n

\"\"
\nMiddle cerebral artery aneurysm visible on CTA

\n

Compared to MR angiography (MRA), CTA's main disadvantage is the use of both ionizing radiation and intravenous iodinated contrast. MRA is a valuable alternative to both CTA and DSA. It avoids the use of ionizing radiation and iodinated contrast agents, and typically does not require intravenous contrast of any type. However, MRA has limitations including lower spatial resolution, longer scan times, and contraindications in patients with some implants such as certain types of heart devices. MRA has evolved into both contrast-enhanced and non-contrast enhanced MRA techniques, each with specific advantages and clinical applications.
\n\"\"
\nMiddle cerebral artery aneurysm visible on MRA

\n

In addition to CTA and MRA, the dataset also includes T1 post-contrast and T2-weighted magnetic resonance imaging (MRI). Although these sequences are not typically used in clinical practice to evaluate the presence of aneurysms, aneurysms may still be visible on them. MRI examinations are performed much more frequently than MRA studies, and including these sequences in the challenge dataset provides an opportunity to explore aneurysm detection from more commonly acquired imaging (e.g. opportunistic screening).
\n\"\"
\nAnterior communicating artery aneurysm visible on T1 post-contrast and T2-weighted MRI

\n

The goal of this competition is to develop machine learning models to detect and localize intracranial saccular aneurysms across a variety of medical imaging modalities, including CTA, MRA and T1 post-contrast and T2-weighted MRI.

\n

Label Description

\n

The dataset includes not only the imaging data (DICOM images along with segmentation labels available for a subset of the cases) but also two accompanying CSV files: train.csv and train_localizers.csv, which provide clinical labels, localization data, and metadata.

\n

train.csv – Contains the primary training labels. Each row corresponds to one imaging series (e.g., CTA, MRA, T1c or T2).

\n\n

train_localizers.csv – Provides localization data for individual aneurysms in the training set.

\n\n

Examples

\n

Here are a few example cases with original and zoomed in images, showing the aneurysm location marked with a crosshair using coordinates provided in train_localizers.csv
\n\"\"
\nBilateral posterior communicating artery aneurysms visible on CTA
\n\"\"
\nRight clinoid/ophthalmic/supraclinoid ICA aneurysm visible on MRA
\n\"\"
\nLeft clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T1-weighted post-contrast MRI
\n\"\"
\nLeft clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T2-weighted MRI

\n

And here are examples of segmentation labels from the segmentations/ directory
\n\"\"
\nRight middle cerebral artery aneurysm visible on original CTA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)
\n \"\"
\nLeft lacerum/petrous/cavernous ICA aneurysm visible on original MRA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)
\n\"\"
\nBasilar tip aneurysm visible on original T2-weighted MRI (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)

", "messages": [ { "id": 3255943, "postDate": "2025-07-29T17:29:08.733Z", "content": "

Overview of the clinical problem

\n

Intracranial aneurysms (also called ”cerebral” or “brain” aneurysms) are a localized abnormal dilation of an intracranial artery. Aneurysms come in many shapes, but “saccular” aneurysms (also called “berry” aneurysms) are the most common form. Macroscopically, saccular aneurysms are rounded lobulated focal outpouchings, usually arising at arterial bifurcations.
\n\"\"
\nFrom Wikipedia

\n

Intracranial aneurysms affect an estimated ~3% of the global population, and in 15-30% of these patients, multiple aneurysms are found. Alarmingly, up to 50% are first identified only after aneurysm rupture, which is a life threatening event. Saccular aneurysms are true aneurysms, meaning the vessel wall is thinned and weakened. Because the wall is thin and weak, and due to the pressure inside the vessel, aneurysms often expand over time. This growth increases the risk of rupture which leads to subarachnoid hemorrhage–a type of stroke caused by bleeding into the subarachnoid space of the brain. A ruptured intracranial aneurysm is the most common cause of non-traumatic subarachnoid hemorrhage. Subarachnoid hemorrhage accounts for 3% of stroke and 5% of stroke deaths. Typical symptoms of brain aneurysm rupture include a severe “thunderclap” headache, often followed by reduced consciousness, and death if left untreated. Intracranial aneurysms are most often asymptomatic until rupture, however occasionally larger aneurysms will result in symptoms before rupture by, for example, pressing on adjacent nerves.

\n

Intracranial aneurysms can be challenging to detect given that they are often small and asymptomatic, however, even small aneurysms pose a risk of rupture leading to hemorrhage and substantial patient morbidity and even death. When detected, aneurysms can often be treated with minimally-invasive procedures that may be life-saving. Large or symptomatic aneurysms are typically managed through endovascular coiling or surgical clipping. The management of small aneurysms remains controversial, but early detection allows for careful monitoring and timely intervention, reducing the risk of rupture.

\n

This challenge primarily focuses on identifying saccular aneurysms. There are also other types of aneurysms including fusiform aneurysms and pseudoaneurysms, which will not be considered as aneurysms for this challenge given their different imaging appearance and risk profile. The task includes both aneurysm detection and localization, because aneurysms may be located anywhere in the brain.

\n

Anatomical Overview

\n

The brain's arterial supply is divided into anterior and posterior circulations. The anterior circulation is primarily supplied by the internal carotid arteries (ICAs), while the posterior circulation comes from the vertebral arteries (VA) and the basilar artery (BA) that is formed where the right and left VA join after entering the skull. The major branches of the posterior circulation include paired posterior inferior cerebellar arteries (PICAs), anterior inferior cerebellar arteries (AICAs), superior cerebellar arteries (SCAs), and posterior cerebral arteries (PCAs). For this challenge, the posterior circulation will be divided into two anatomical locations: the distal end of the BA (referred to as the basilar tip), and the rest of the posterior circulation. The ICA has several different segments after entering the skull. An important anatomical landmark is where the ICA enters the dura (a fibrous covering of the brain) and after which a potential aneurysm rupture will result in subarachnoid hemorrhage. The clinical significance of this anatomic landmark is the reason that the ICA is divided into supraclinoid and infraclinoid ICA for this challenge. The major branches of the ICA include paired middle cerebral arteries (MCAs) and anterior cerebral arteries (ACAs).

\n

The ICAs and the BAs communicate at the base of the brain via the circle of Willis, a circular connection of arteries that helps maintain blood flow even if one vessel is compromised. The circle of Willis is formed from parts of the bilateral ACAs and PCAs linked via the anterior communicating artery (ACom) and paired posterior communicating arteries (Pcoms). The ACom arises from the ACA and acts as an anastomosis between the left and right anterior cerebral circulation. The PCom connects the anterior circulation (ICAs) to the posterior circulation (PCAs). This description pertains to the most common configuration of the circle of Willis; however, there are many described normal variants with slightly different connections.
\n \"\"
\nFrom Radiopaedia, Case courtesy of Sachi Hapugoda

\n

You will need to predict the presence or absence of aneurysms in the following 13 anatomical locations for each imaging series:
\n \"\"

\n

Imaging Overview

\n

Aneurysms can be identified with a variety of imaging modalities:

\n\n

Each method has its own advantages and limitations. However, DSA, particularly with 3D acquisitions, is generally considered the “gold standard” because of its high spatial and temporal resolution.

\n

CT angiography (CTA) is a non-invasive technique that enables visualization of the blood vessels. It offers several advantages over DSA, including the ability to also assess non-vascular tissues, such as the brain tissue. Additionally, it is less expensive, faster, and presents a lower risk to the patient because it does not require insertion of a catheter into the cerebral arteries. Despite its benefits, CTA has a few limitations compared to DSA. It cannot selectively image individual vessels, and because it images the vessels at a single time point, it limits the evaluation of flow-related features. CTA also has a lower spatial resolution, making it more difficult to detect small aneurysms.

\n

\"\"
\nMiddle cerebral artery aneurysm visible on CTA

\n

Compared to MR angiography (MRA), CTA's main disadvantage is the use of both ionizing radiation and intravenous iodinated contrast. MRA is a valuable alternative to both CTA and DSA. It avoids the use of ionizing radiation and iodinated contrast agents, and typically does not require intravenous contrast of any type. However, MRA has limitations including lower spatial resolution, longer scan times, and contraindications in patients with some implants such as certain types of heart devices. MRA has evolved into both contrast-enhanced and non-contrast enhanced MRA techniques, each with specific advantages and clinical applications.
\n\"\"
\nMiddle cerebral artery aneurysm visible on MRA

\n

In addition to CTA and MRA, the dataset also includes T1 post-contrast and T2-weighted magnetic resonance imaging (MRI). Although these sequences are not typically used in clinical practice to evaluate the presence of aneurysms, aneurysms may still be visible on them. MRI examinations are performed much more frequently than MRA studies, and including these sequences in the challenge dataset provides an opportunity to explore aneurysm detection from more commonly acquired imaging (e.g. opportunistic screening).
\n\"\"
\nAnterior communicating artery aneurysm visible on T1 post-contrast and T2-weighted MRI

\n

The goal of this competition is to develop machine learning models to detect and localize intracranial saccular aneurysms across a variety of medical imaging modalities, including CTA, MRA and T1 post-contrast and T2-weighted MRI.

\n

Label Description

\n

The dataset includes not only the imaging data (DICOM images along with segmentation labels available for a subset of the cases) but also two accompanying CSV files: train.csv and train_localizers.csv, which provide clinical labels, localization data, and metadata.

\n

train.csv – Contains the primary training labels. Each row corresponds to one imaging series (e.g., CTA, MRA, T1c or T2).

\n\n

train_localizers.csv – Provides localization data for individual aneurysms in the training set.

\n\n

Examples

\n

Here are a few example cases with original and zoomed in images, showing the aneurysm location marked with a crosshair using coordinates provided in train_localizers.csv
\n\"\"
\nBilateral posterior communicating artery aneurysms visible on CTA
\n\"\"
\nRight clinoid/ophthalmic/supraclinoid ICA aneurysm visible on MRA
\n\"\"
\nLeft clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T1-weighted post-contrast MRI
\n\"\"
\nLeft clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T2-weighted MRI

\n

And here are examples of segmentation labels from the segmentations/ directory
\n\"\"
\nRight middle cerebral artery aneurysm visible on original CTA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)
\n \"\"
\nLeft lacerum/petrous/cavernous ICA aneurysm visible on original MRA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)
\n\"\"
\nBasilar tip aneurysm visible on original T2-weighted MRI (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)

", "rawMarkdown": "##Overview of the clinical problem##\nIntracranial aneurysms (also called ”cerebral” or “brain” aneurysms) are a localized abnormal dilation of an intracranial artery. Aneurysms come in many shapes, but “saccular” aneurysms (also called “berry” aneurysms) are the most common form. Macroscopically, saccular aneurysms are rounded lobulated focal outpouchings, usually arising at arterial bifurcations.\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F2b70681e779a57dd130594ff71a8b62b%2F1.jpg?generation=1753809739289565&alt=media)\n*From [Wikipedia](https://en.wikipedia.org/wiki/File:Cerebral_aneurysm_NIH.jpg)*\n\nIntracranial aneurysms affect an estimated ~3% of the global population, and in 15-30% of these patients, multiple aneurysms are found. Alarmingly, up to 50% are first identified only after aneurysm rupture, which is a life threatening event. Saccular aneurysms are true aneurysms, meaning the vessel wall is thinned and weakened. Because the wall is thin and weak, and due to the pressure inside the vessel, aneurysms often expand over time. This growth increases the risk of rupture which leads to subarachnoid hemorrhage–a type of stroke caused by bleeding into the subarachnoid space of the brain. A ruptured intracranial aneurysm is the most common cause of non-traumatic subarachnoid hemorrhage. Subarachnoid hemorrhage accounts for 3% of stroke and 5% of stroke deaths. Typical symptoms of brain aneurysm rupture include a severe “thunderclap” headache, often followed by reduced consciousness, and death if left untreated. Intracranial aneurysms are most often asymptomatic until rupture, however occasionally larger aneurysms will result in symptoms before rupture by, for example, pressing on adjacent nerves. \n\nIntracranial aneurysms can be challenging to detect given that they are often small and asymptomatic, however, even small aneurysms pose a risk of rupture leading to hemorrhage and substantial patient morbidity and even death. When detected, aneurysms can often be treated with minimally-invasive procedures that may be life-saving. Large or symptomatic aneurysms are typically managed through endovascular coiling or surgical clipping. The management of small aneurysms remains controversial, but early detection allows for careful monitoring and timely intervention, reducing the risk of rupture.\n\nThis challenge primarily focuses on identifying saccular aneurysms. There are also other types of aneurysms including fusiform aneurysms and pseudoaneurysms, which will not be considered as aneurysms for this challenge given their different imaging appearance and risk profile. The task includes both aneurysm detection and localization, because aneurysms may be located anywhere in the brain. \n##Anatomical Overview##\nThe brain's arterial supply is divided into anterior and posterior circulations. The anterior circulation is primarily supplied by the internal carotid arteries (ICAs), while the posterior circulation comes from the vertebral arteries (VA) and the basilar artery (BA) that is formed where the right and left VA join after entering the skull. The major branches of the posterior circulation include paired posterior inferior cerebellar arteries (PICAs), anterior inferior cerebellar arteries (AICAs), superior cerebellar arteries (SCAs), and posterior cerebral arteries (PCAs). For this challenge, the posterior circulation will be divided into two anatomical locations: the distal end of the BA (referred to as the basilar tip), and the rest of the posterior circulation. The ICA has several different segments after entering the skull. An important anatomical landmark is where the ICA enters the dura (a fibrous covering of the brain) and after which a potential aneurysm rupture will result in subarachnoid hemorrhage. The clinical significance of this anatomic landmark is the reason that the ICA is divided into supraclinoid and infraclinoid ICA for this challenge. The major branches of the ICA include paired middle cerebral arteries (MCAs) and anterior cerebral arteries (ACAs).\n\nThe ICAs and the BAs communicate at the base of the brain via the circle of Willis, a circular connection of arteries that helps maintain blood flow even if one vessel is compromised. The circle of Willis is formed from parts of the bilateral ACAs and PCAs linked via the anterior communicating artery (ACom) and paired posterior communicating arteries (Pcoms). The ACom arises from the ACA and acts as an anastomosis between the left and right anterior cerebral circulation. The PCom connects the anterior circulation (ICAs) to the posterior circulation (PCAs). This description pertains to the most common configuration of the circle of Willis; however, there are many described normal variants with slightly different connections.\n ![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F288432c90058928e85241fd6a7974abf%2F2.jpg?generation=1753809377924520&alt=media)\n*From [Radiopaedia](https://radiopaedia.org/cases/51777/studies/57570), Case courtesy of Sachi Hapugoda* \n\nYou will need to predict the presence or absence of aneurysms in the following 13 anatomical locations for each imaging series:\n ![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F576c061180423d74ae758eafbb333815%2F3.png?generation=1753809391297813&alt=media)\n\n##Imaging Overview##\nAneurysms can be identified with a variety of imaging modalities:\n-\tComputed tomography (CT) angiography\n-\tMagnetic resonance (MR) imaging including angiography\n-\tDigital subtraction angiography (DSA)\n\nEach method has its own advantages and limitations. However, DSA, particularly with 3D acquisitions, is generally considered the “gold standard” because of its high spatial and temporal resolution.\n\nCT angiography (CTA) is a non-invasive technique that enables visualization of the blood vessels. It offers several advantages over DSA, including the ability to also assess non-vascular tissues, such as the brain tissue. Additionally, it is less expensive, faster, and presents a lower risk to the patient because it does not require insertion of a catheter into the cerebral arteries. Despite its benefits, CTA has a few limitations compared to DSA. It cannot selectively image individual vessels, and because it images the vessels at a single time point, it limits the evaluation of flow-related features. CTA also has a lower spatial resolution, making it more difficult to detect small aneurysms. \n\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2Fbe737198927d6ef4c597915e4f6bf8bf%2F4.png?generation=1753809895419714&alt=media)\n*Middle cerebral artery aneurysm visible on CTA*\n\nCompared to MR angiography (MRA), CTA's main disadvantage is the use of both ionizing radiation and intravenous iodinated contrast. MRA is a valuable alternative to both CTA and DSA. It avoids the use of ionizing radiation and iodinated contrast agents, and typically does not require intravenous contrast of any type. However, MRA has limitations including lower spatial resolution, longer scan times, and contraindications in patients with some implants such as certain types of heart devices. MRA has evolved into both contrast-enhanced and non-contrast enhanced MRA techniques, each with specific advantages and clinical applications.\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F289eb80b86d83f06323baf7db58f2d77%2F5.png?generation=1753809419296282&alt=media)\n*Middle cerebral artery aneurysm visible on MRA*\n\nIn addition to CTA and MRA, the dataset also includes T1 post-contrast and T2-weighted magnetic resonance imaging (MRI). Although these sequences are not typically used in clinical practice to evaluate the presence of aneurysms, aneurysms may still be visible on them. MRI examinations are performed much more frequently than MRA studies, and including these sequences in the challenge dataset provides an opportunity to explore aneurysm detection from more commonly acquired imaging (e.g. opportunistic screening).\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F3e2755d72c03200c7e79a9371fe97603%2F6.png?generation=1753809470235384&alt=media)\n*Anterior communicating artery aneurysm visible on T1 post-contrast and T2-weighted MRI*\n\nThe goal of this competition is to develop machine learning models to detect and localize intracranial saccular aneurysms across a variety of medical imaging modalities, including CTA, MRA and T1 post-contrast and T2-weighted MRI.\n\n##Label Description##\nThe dataset includes not only the imaging data (DICOM images along with segmentation labels available for a subset of the cases) but also two accompanying CSV files: train.csv and train_localizers.csv, which provide clinical labels, localization data, and metadata.\n\n**train.csv** – Contains the primary training labels. Each row corresponds to one imaging series (e.g., CTA, MRA, T1c or T2).\n-\tSeriesInstanceUID: Unique identifier for each series.\n-\tPatientAge: Patient’s age in years.\n-\tPatientSex: Patient’s gender (Male/Female).\n-\tModality: Modality of the series (CTA, MRA, MRI T2 or MRI T1post)\n*Location-Specific Aneurysm Labels* (13 binary labels indicating presence/absence of aneurysms in specific anatomical locations, 1 denotes the presence of an aneurysm and 0 denotes its absence):\n-\tLeft Infraclinoid Internal Carotid Artery\n-\tRight Infraclinoid Internal Carotid Artery\n-\tLeft Supraclinoid Internal Carotid Artery\n-\tRight Supraclinoid Internal Carotid Artery\n-\tLeft Middle Cerebral Artery\n-\tRight Middle Cerebral Artery\n-\tAnterior Communicating Artery\n-\tLeft Anterior Cerebral Artery\n-\tRight Anterior Cerebral Artery\n-\tLeft Posterior Communicating Artery\n-\tRight Posterior Communicating Artery\n-\tBasilar Tip\n-\tOther Posterior Circulation: Posterior circulation excluding the basilar tip (e.g., mid-basilar, vertebral, PICA, AICA, SCA, PCA)\n-\tAneurysm Present: Indicates whether an aneurysm is present anywhere in the series (binary label, 1 denotes the presence of an aneurysm and 0 denotes its absence).\n\n**train_localizers.csv** – Provides localization data for individual aneurysms in the training set.\n-\tSeriesInstanceUID: Unique identifier for the imaging series (can be used to join with train.csv).\n-\tSOPInstanceUID: Unique identifier for a specific DICOM image within the series.\n-\tcoordinates: (x, y) coordinates of the aneurysm location in the image.\n-\tlocation: Text description of the aneurysm's anatomical location, corresponding to one of the 13 location-specific aneurysm labels in train.csv.\n\n##Examples##\nHere are a few example cases with original and zoomed in images, showing the aneurysm location marked with a crosshair using coordinates provided in train_localizers.csv\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2Fc019ce7af3dcc58d512cc93634aba4ab%2F7.png?generation=1753809492742334&alt=media)\n*Bilateral posterior communicating artery aneurysms visible on CTA*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F908b0d67592b3b54e21af2383f0b1763%2F8.png?generation=1753809609468772&alt=media)\n*Right clinoid/ophthalmic/supraclinoid ICA aneurysm visible on MRA*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F93753f97387e62bdc05fd7bab102c27c%2F9.png?generation=1753809592599340&alt=media)\n*Left clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T1-weighted post-contrast MRI*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F194628e6ead243484842c87ebe23133e%2F10.png?generation=1753809578660306&alt=media)\n*Left clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T2-weighted MRI*\n\nAnd here are examples of segmentation labels from the segmentations/ directory\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F510bb2d9ad2d890f69ee17b5881357c8%2F11.png?generation=1753809565257194&alt=media)\n*Right middle cerebral artery aneurysm visible on original CTA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)*\n ![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F9b43bc8f1572f0f12799594be99e89a7%2F12.1.png?generation=1753809544818904&alt=media)\n*Left lacerum/petrous/cavernous ICA aneurysm visible on original MRA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F0fd66a478d91db09f8172b6603d061b4%2F13.png?generation=1753809520280320&alt=media)\n*Basilar tip aneurysm visible on original T2-weighted MRI (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)*\n", "votes": 90 }, { "id": 3259105, "postDate": "2025-07-31T22:07:29.717Z", "content": "

Awesome content! Learned a ton from this—thanks for putting it together.

", "rawMarkdown": "Awesome content! Learned a ton from this—thanks for putting it together.", "votes": 1 }, { "id": 3272760, "postDate": "2025-08-21T14:50:43.440Z", "content": "

tack sa mycket dear Maria.. Very interesting.

", "rawMarkdown": "tack sa mycket dear Maria.. Very interesting. " }, { "id": 3263363, "postDate": "2025-08-05T05:27:50.590Z", "content": "

Very good explanation

", "rawMarkdown": "Very good explanation" }, { "id": 3262873, "postDate": "2025-08-04T12:00:04.570Z", "content": "

Thank you for this detailed discription, So much great info and context here.

", "rawMarkdown": "Thank you for this detailed discription, So much great info and context here." }, { "id": 3262453, "postDate": "2025-08-03T16:27:50.697Z", "content": "

Amazing way to get into a project!

", "rawMarkdown": "Amazing way to get into a project!" }, { "id": 3258510, "postDate": "2025-07-30T19:29:37.650Z", "content": "

Thank you for the introduction and nice description!

", "rawMarkdown": "Thank you for the introduction and nice description!" }, { "id": 3258188, "postDate": "2025-07-30T09:25:17.153Z", "content": "

Thank you for this detailed discription

", "rawMarkdown": "Thank you for this detailed discription " }, { "id": 3256976, "postDate": "2025-07-29T19:19:38.420Z", "content": "

Thanks for this brief introduction, now we can move on with clear understandings.

", "rawMarkdown": "Thanks for this brief introduction, now we can move on with clear understandings.", "replies": [ { "id": 3258393, "postDate": "2025-07-30T16:32:34.717Z", "content": "

Glad it was helpful!

", "rawMarkdown": "Glad it was helpful!" } ] }, { "id": 3255967, "postDate": "2025-07-29T18:27:45.960Z", "content": "

Thanks for this amazing post! So much great info and context here.

", "rawMarkdown": "Thanks for this amazing post! So much great info and context here." }, { "id": 3280608, "postDate": "2025-09-02T23:58:05.960Z", "rawMarkdown": "", "isDeleted": true }, { "id": 3259154, "postDate": "2025-08-01T01:42:58.670Z", "content": "

Very detailed explanation, thank you.

", "rawMarkdown": "Very detailed explanation, thank you." }, { "id": 3258717, "postDate": "2025-07-31T05:28:37.920Z", "content": "

Thanks for this amazing post!

", "rawMarkdown": "Thanks for this amazing post! " } ], "comments": [ { "id": 3259105, "author_name": "Dmitriy Bulgakov", "author_url": "", "post_date": "2025-07-31T22:07:29.717000", "content": "

Awesome content! Learned a ton from this—thanks for putting it together.

", "votes": 1, "replies": [] }, { "id": 3272760, "author_name": "NikolAiD153", "author_url": "", "post_date": "2025-08-21T14:50:43.440000", "content": "

tack sa mycket dear Maria.. Very interesting.

", "votes": 0, "replies": [] }, { "id": 3263363, "author_name": "Rohit Chaudhari", "author_url": "", "post_date": "2025-08-05T05:27:50.590000", "content": "

Very good explanation

", "votes": 0, "replies": [] }, { "id": 3262873, "author_name": "Rohingarg12", "author_url": "", "post_date": "2025-08-04T12:00:04.570000", "content": "

Thank you for this detailed discription, So much great info and context here.

", "votes": 0, "replies": [] }, { "id": 3262453, "author_name": "Muhammed Rasin", "author_url": "", "post_date": "2025-08-03T16:27:50.697000", "content": "

Amazing way to get into a project!

", "votes": 0, "replies": [] }, { "id": 3258510, "author_name": "Leiner Barba", "author_url": "", "post_date": "2025-07-30T19:29:37.650000", "content": "

Thank you for the introduction and nice description!

", "votes": 0, "replies": [] }, { "id": 3258188, "author_name": "Keshav Gairola", "author_url": "", "post_date": "2025-07-30T09:25:17.153000", "content": "

Thank you for this detailed discription

", "votes": 0, "replies": [] }, { "id": 3256976, "author_name": "Zain Ali", "author_url": "", "post_date": "2025-07-29T19:19:38.420000", "content": "

Thanks for this brief introduction, now we can move on with clear understandings.

", "votes": 0, "replies": [ { "id": 3258393, "author_name": "Maria Correia de Verdier", "author_url": "", "post_date": "2025-07-30T16:32:34.717000", "content": "

Glad it was helpful!

", "votes": 0, "replies": [] } ] }, { "id": 3255967, "author_name": "Evan Calabrese", "author_url": "", "post_date": "2025-07-29T18:27:45.960000", "content": "

Thanks for this amazing post! So much great info and context here.

", "votes": 0, "replies": [] }, { "id": 3280608, "author_name": "", "author_url": "", "post_date": "2025-09-02T23:58:05.960000", "content": "", "votes": 0, "replies": [] }, { "id": 3259154, "author_name": "FUFU", "author_url": "", "post_date": "2025-08-01T01:42:58.670000", "content": "

Very detailed explanation, thank you.

", "votes": 0, "replies": [] }, { "id": 3258717, "author_name": "Khushi Yadav", "author_url": "", "post_date": "2025-07-31T05:28:37.920000", "content": "

Thanks for this amazing post!

", "votes": 0, "replies": [] } ], "raw_markdown_by_id": { "3255943": "##Overview of the clinical problem##\nIntracranial aneurysms (also called ”cerebral” or “brain” aneurysms) are a localized abnormal dilation of an intracranial artery. Aneurysms come in many shapes, but “saccular” aneurysms (also called “berry” aneurysms) are the most common form. Macroscopically, saccular aneurysms are rounded lobulated focal outpouchings, usually arising at arterial bifurcations.\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F2b70681e779a57dd130594ff71a8b62b%2F1.jpg?generation=1753809739289565&alt=media)\n*From [Wikipedia](https://en.wikipedia.org/wiki/File:Cerebral_aneurysm_NIH.jpg)*\n\nIntracranial aneurysms affect an estimated ~3% of the global population, and in 15-30% of these patients, multiple aneurysms are found. Alarmingly, up to 50% are first identified only after aneurysm rupture, which is a life threatening event. Saccular aneurysms are true aneurysms, meaning the vessel wall is thinned and weakened. Because the wall is thin and weak, and due to the pressure inside the vessel, aneurysms often expand over time. This growth increases the risk of rupture which leads to subarachnoid hemorrhage–a type of stroke caused by bleeding into the subarachnoid space of the brain. A ruptured intracranial aneurysm is the most common cause of non-traumatic subarachnoid hemorrhage. Subarachnoid hemorrhage accounts for 3% of stroke and 5% of stroke deaths. Typical symptoms of brain aneurysm rupture include a severe “thunderclap” headache, often followed by reduced consciousness, and death if left untreated. Intracranial aneurysms are most often asymptomatic until rupture, however occasionally larger aneurysms will result in symptoms before rupture by, for example, pressing on adjacent nerves. \n\nIntracranial aneurysms can be challenging to detect given that they are often small and asymptomatic, however, even small aneurysms pose a risk of rupture leading to hemorrhage and substantial patient morbidity and even death. When detected, aneurysms can often be treated with minimally-invasive procedures that may be life-saving. Large or symptomatic aneurysms are typically managed through endovascular coiling or surgical clipping. The management of small aneurysms remains controversial, but early detection allows for careful monitoring and timely intervention, reducing the risk of rupture.\n\nThis challenge primarily focuses on identifying saccular aneurysms. There are also other types of aneurysms including fusiform aneurysms and pseudoaneurysms, which will not be considered as aneurysms for this challenge given their different imaging appearance and risk profile. The task includes both aneurysm detection and localization, because aneurysms may be located anywhere in the brain. \n##Anatomical Overview##\nThe brain's arterial supply is divided into anterior and posterior circulations. The anterior circulation is primarily supplied by the internal carotid arteries (ICAs), while the posterior circulation comes from the vertebral arteries (VA) and the basilar artery (BA) that is formed where the right and left VA join after entering the skull. The major branches of the posterior circulation include paired posterior inferior cerebellar arteries (PICAs), anterior inferior cerebellar arteries (AICAs), superior cerebellar arteries (SCAs), and posterior cerebral arteries (PCAs). For this challenge, the posterior circulation will be divided into two anatomical locations: the distal end of the BA (referred to as the basilar tip), and the rest of the posterior circulation. The ICA has several different segments after entering the skull. An important anatomical landmark is where the ICA enters the dura (a fibrous covering of the brain) and after which a potential aneurysm rupture will result in subarachnoid hemorrhage. The clinical significance of this anatomic landmark is the reason that the ICA is divided into supraclinoid and infraclinoid ICA for this challenge. The major branches of the ICA include paired middle cerebral arteries (MCAs) and anterior cerebral arteries (ACAs).\n\nThe ICAs and the BAs communicate at the base of the brain via the circle of Willis, a circular connection of arteries that helps maintain blood flow even if one vessel is compromised. The circle of Willis is formed from parts of the bilateral ACAs and PCAs linked via the anterior communicating artery (ACom) and paired posterior communicating arteries (Pcoms). The ACom arises from the ACA and acts as an anastomosis between the left and right anterior cerebral circulation. The PCom connects the anterior circulation (ICAs) to the posterior circulation (PCAs). This description pertains to the most common configuration of the circle of Willis; however, there are many described normal variants with slightly different connections.\n ![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F288432c90058928e85241fd6a7974abf%2F2.jpg?generation=1753809377924520&alt=media)\n*From [Radiopaedia](https://radiopaedia.org/cases/51777/studies/57570), Case courtesy of Sachi Hapugoda* \n\nYou will need to predict the presence or absence of aneurysms in the following 13 anatomical locations for each imaging series:\n ![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F576c061180423d74ae758eafbb333815%2F3.png?generation=1753809391297813&alt=media)\n\n##Imaging Overview##\nAneurysms can be identified with a variety of imaging modalities:\n-\tComputed tomography (CT) angiography\n-\tMagnetic resonance (MR) imaging including angiography\n-\tDigital subtraction angiography (DSA)\n\nEach method has its own advantages and limitations. However, DSA, particularly with 3D acquisitions, is generally considered the “gold standard” because of its high spatial and temporal resolution.\n\nCT angiography (CTA) is a non-invasive technique that enables visualization of the blood vessels. It offers several advantages over DSA, including the ability to also assess non-vascular tissues, such as the brain tissue. Additionally, it is less expensive, faster, and presents a lower risk to the patient because it does not require insertion of a catheter into the cerebral arteries. Despite its benefits, CTA has a few limitations compared to DSA. It cannot selectively image individual vessels, and because it images the vessels at a single time point, it limits the evaluation of flow-related features. CTA also has a lower spatial resolution, making it more difficult to detect small aneurysms. \n\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2Fbe737198927d6ef4c597915e4f6bf8bf%2F4.png?generation=1753809895419714&alt=media)\n*Middle cerebral artery aneurysm visible on CTA*\n\nCompared to MR angiography (MRA), CTA's main disadvantage is the use of both ionizing radiation and intravenous iodinated contrast. MRA is a valuable alternative to both CTA and DSA. It avoids the use of ionizing radiation and iodinated contrast agents, and typically does not require intravenous contrast of any type. However, MRA has limitations including lower spatial resolution, longer scan times, and contraindications in patients with some implants such as certain types of heart devices. MRA has evolved into both contrast-enhanced and non-contrast enhanced MRA techniques, each with specific advantages and clinical applications.\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F289eb80b86d83f06323baf7db58f2d77%2F5.png?generation=1753809419296282&alt=media)\n*Middle cerebral artery aneurysm visible on MRA*\n\nIn addition to CTA and MRA, the dataset also includes T1 post-contrast and T2-weighted magnetic resonance imaging (MRI). Although these sequences are not typically used in clinical practice to evaluate the presence of aneurysms, aneurysms may still be visible on them. MRI examinations are performed much more frequently than MRA studies, and including these sequences in the challenge dataset provides an opportunity to explore aneurysm detection from more commonly acquired imaging (e.g. opportunistic screening).\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F3e2755d72c03200c7e79a9371fe97603%2F6.png?generation=1753809470235384&alt=media)\n*Anterior communicating artery aneurysm visible on T1 post-contrast and T2-weighted MRI*\n\nThe goal of this competition is to develop machine learning models to detect and localize intracranial saccular aneurysms across a variety of medical imaging modalities, including CTA, MRA and T1 post-contrast and T2-weighted MRI.\n\n##Label Description##\nThe dataset includes not only the imaging data (DICOM images along with segmentation labels available for a subset of the cases) but also two accompanying CSV files: train.csv and train_localizers.csv, which provide clinical labels, localization data, and metadata.\n\n**train.csv** – Contains the primary training labels. Each row corresponds to one imaging series (e.g., CTA, MRA, T1c or T2).\n-\tSeriesInstanceUID: Unique identifier for each series.\n-\tPatientAge: Patient’s age in years.\n-\tPatientSex: Patient’s gender (Male/Female).\n-\tModality: Modality of the series (CTA, MRA, MRI T2 or MRI T1post)\n*Location-Specific Aneurysm Labels* (13 binary labels indicating presence/absence of aneurysms in specific anatomical locations, 1 denotes the presence of an aneurysm and 0 denotes its absence):\n-\tLeft Infraclinoid Internal Carotid Artery\n-\tRight Infraclinoid Internal Carotid Artery\n-\tLeft Supraclinoid Internal Carotid Artery\n-\tRight Supraclinoid Internal Carotid Artery\n-\tLeft Middle Cerebral Artery\n-\tRight Middle Cerebral Artery\n-\tAnterior Communicating Artery\n-\tLeft Anterior Cerebral Artery\n-\tRight Anterior Cerebral Artery\n-\tLeft Posterior Communicating Artery\n-\tRight Posterior Communicating Artery\n-\tBasilar Tip\n-\tOther Posterior Circulation: Posterior circulation excluding the basilar tip (e.g., mid-basilar, vertebral, PICA, AICA, SCA, PCA)\n-\tAneurysm Present: Indicates whether an aneurysm is present anywhere in the series (binary label, 1 denotes the presence of an aneurysm and 0 denotes its absence).\n\n**train_localizers.csv** – Provides localization data for individual aneurysms in the training set.\n-\tSeriesInstanceUID: Unique identifier for the imaging series (can be used to join with train.csv).\n-\tSOPInstanceUID: Unique identifier for a specific DICOM image within the series.\n-\tcoordinates: (x, y) coordinates of the aneurysm location in the image.\n-\tlocation: Text description of the aneurysm's anatomical location, corresponding to one of the 13 location-specific aneurysm labels in train.csv.\n\n##Examples##\nHere are a few example cases with original and zoomed in images, showing the aneurysm location marked with a crosshair using coordinates provided in train_localizers.csv\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2Fc019ce7af3dcc58d512cc93634aba4ab%2F7.png?generation=1753809492742334&alt=media)\n*Bilateral posterior communicating artery aneurysms visible on CTA*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F908b0d67592b3b54e21af2383f0b1763%2F8.png?generation=1753809609468772&alt=media)\n*Right clinoid/ophthalmic/supraclinoid ICA aneurysm visible on MRA*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F93753f97387e62bdc05fd7bab102c27c%2F9.png?generation=1753809592599340&alt=media)\n*Left clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T1-weighted post-contrast MRI*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F194628e6ead243484842c87ebe23133e%2F10.png?generation=1753809578660306&alt=media)\n*Left clinoid/ophthalmic/supraclinoid ICA aneurysm visible on T2-weighted MRI*\n\nAnd here are examples of segmentation labels from the segmentations/ directory\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F510bb2d9ad2d890f69ee17b5881357c8%2F11.png?generation=1753809565257194&alt=media)\n*Right middle cerebral artery aneurysm visible on original CTA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)*\n ![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F9b43bc8f1572f0f12799594be99e89a7%2F12.1.png?generation=1753809544818904&alt=media)\n*Left lacerum/petrous/cavernous ICA aneurysm visible on original MRA (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)*\n![](https://www.googleapis.com/download/storage/v1/b/kaggle-forum-message-attachments/o/inbox%2F26385455%2F0fd66a478d91db09f8172b6603d061b4%2F13.png?generation=1753809520280320&alt=media)\n*Basilar tip aneurysm visible on original T2-weighted MRI (left), shown with vessel segmentation overlays (middle) and 3D reconstruction (right)*\n", "3259105": "Awesome content! Learned a ton from this—thanks for putting it together.", "3272760": "tack sa mycket dear Maria.. Very interesting. ", "3263363": "Very good explanation", "3262873": "Thank you for this detailed discription, So much great info and context here.", "3262453": "Amazing way to get into a project!", "3258510": "Thank you for the introduction and nice description!", "3258188": "Thank you for this detailed discription ", "3256976": "Thanks for this brief introduction, now we can move on with clear understandings.", "3255967": "Thanks for this amazing post! So much great info and context here.", "3280608": "", "3259154": "Very detailed explanation, thank you.", "3258717": "Thanks for this amazing post! " } }