The differentiating presentations are suggestive of FMD being a unique syndrome in respect to the pediatric population. Experienced FMD clinicians warn against relying in the “string of beads” angiography for a diagnosis. In fact, it is suggested that FMD may be both under and over-diagnosed in children with stroke.

It is the lack of specific symptoms and its potential to appear anywhere that makes FMD a challenge to detect early on. The most accurate diagnosis comes from combining clinical presentation and angiographic imaging. According to the Michigan Outcomes Research and Reporting Program (MCORRP, 2013) the length of time from a patient’s first signs or symptoms to diagnosis is commonly 5 years.

FMD is currently diagnosed through the use of both invasive and non-invasive tests. Non-invasive testing includes duplex ultrasonography, magnetic resonance angiography (MRA), and computed tomographic angiography (CTA). Invasive testing through angiography is the gold standard. However, due to the higher risk of complications this is typically not done early on. Occasionally, FMD is diagnosed asymptomatically after an unrelated x-ray presents the classic ‘string of beads’ appearance of the arteries, or when a practitioner investigates an unexpected bruit found during an exam. When a diagnosis of FMD is considered for a patient thorough medical history, family history as well as vascular examination should be completed.

A definitive diagnosis of FMD can only be made with imaging studies. Catheter-based angiography (with contrast) has proven to be the most accurate imaging technique: this test involves a catheter is inserted into a large artery and advanced until it reaches the vessel of question. The catheter allows practitioners to view and measure the pressure of the artery aiding in the categorization and severity of the FMD diseased artery. According to Olin, “catheter-based angiography is the only imaging modality that can accurately identify the changes of FMD, aneurysm formation, and dissection in the branch vessels.” Practitioners believe it is important to utilize IVUS imaging because stenosis can sometimes only be detected through the methods of pressure gradient or IVUS imaging. In addition, computed tomography angiography and magnetic resonance angiography are commonly used to evaluate arteries in the brain. Doppler ultrasound may be used in both the diagnosis and follow-up of FMD.

Diagnosis is based on the demonstration of vascular lesions in large and middle-sized vessels on angiography, CT scan, magnetic resonance angiography or FDG PET. FDG PET can help in diagnosis of active inflammation not just in patients with active Takayasu arteritis prior to treatment but also in addition in relapsing patients receiving immunosuppressive agents.

Contrast angiography has been the gold standard. The earliest detectable lesion is a local narrowing or irregularity of the lumen. This may develop into stenosis and occlusion. The characteristic finding is the presence of "skip lesions," where stenosis or aneurysms alternate with normal vessels. Angiography provides information on vessel anatomy and patency but does not provide information on the degree of inflammation in the wall.

The age at onset helps to differentiate Takayasu's arteritis from other types of large vessel vasculitis. For example, Takaysu's arteritis has an age of onset of 60 years.

Takayasu arteritis is not associated with ANCA, rheumatoid factor, ANA, and anticardiolipin antibodies.

In terms of the diagnosis of arterial tortuosity syndrome can be done via genetic testing, as well as the following listed below:

- CT

- MRI

- Echocardiogram

- Physical exam(for specific characteristics)

The treatment of arterial tortuosity syndrome entails possible surgery for aortic aneurysms, as well as, follow ups which should consist of EGC. The prognosis of this condition has it at about 12% mortality

There are no diagnostic tests on which all Sneddon's patients will have abnormal results, although brain MRI and skin biopsy are often abnormal. The diagnosis is based on a detailed history and physical examination. About 40-60% of patients with the syndrome test positive for antiphospholipid antibodies.

In order to treat acute limb ischaemia there are a series of things that can be done to determine where the occlusion is located, the severity, and what the cause was. To find out where the occlusion is located one of the things that can be done is simply a pulse examination to see where the heart rate can be detected and where it stops being sensed. Also there is a lower body temperature below the occlusion as well as paleness. A Doppler evaluation is used to show the extent and severity of the ischaemia by showing flow in smaller arteries. Other diagnostical tools are duplex ultrasonography, computed tomography angiography (CTA), and magnetic resonance angiography (MRA). The CTA and MRA are used most often because the duplex ultrasonography although non-invasive is not precise in planning revascularization. CTA uses radiation and may not pick up on vessels for revascularization that are distal to the occlusion, but it is much quicker than MRA. In treating acute limb ischaemia time is everything.

In the worst cases acute limb ischaemia progresses to critical limb ischaemia, and results in death or limb loss. Early detection and steps towards fixing the problem with limb-sparing techniques can salvage the limb. Compartment syndrome can occur because of acute limb ischaemia because of the biotoxins that accumulate distal to the occlusion resulting in edema.

Another type of thrombolysis disrupts the clot mechanically using either saline jets or, more recently, ultrasound waves. Saline jets dislodge the clot using the Bernoulli effect. Ultrasound waves, emitted at low frequency, create a physical fragmentation of the thrombus.

Sneddon's patients are generally treated with warfarin, maintaining a high INR of 3-4. Because most will experience significant relief of symptoms after several months of consistent INR in this range, treatment with warfarin is often used as a diagnostic tool.

The evaluation for VBI starts with a history and physical exam, with great emphasis on the cardiovascular and neurologic exam. It also includes a work-up to exclude benign conditions (such as labyrinthitis, vestibular neuronitis, and benign paroxysmal positional vertigo) that have overlapping signs and symptoms. However, the exact work-up largely depends on the patient’s age and known risk factors. For middle-aged patients, a cardiovascular risk factor evaluation is important. This often includes a cholesterol level, lipid profile (see this to determine what your cholesterol level means), ECG, and echocardiogram. If a person with VBI is under age 45 and has no evidence for atherosclerosis, a work-up for hypercoagulable states (Lupus anticoagulant, anti-cardiolipin antibodies, is indicated. Screening for protein C, protein S, or antithrombin III deficiency is sometimes recommended but these are more usually responsible for venous thrombosis than arterial problems.

Imaging studies are rarely required to diagnose VBI, but sometimes computed tomography (CT) is performed first. The CT is extremely sensitive in detecting hemorrhage. However, magnetic resonance imaging (MRI) is superior to the CT in detecting ischemic changes in the vertebrobasilar distribution. Magnetic resonance angiography (MRA) also can be used to identify vertebrobasilar stenoses or occlusions, but it can often overestimate the degree of stenosis, or wrongly show stenosis as an occlusion. Intracranial MRA is mostly sufficient to evaluate vertebrobasilar arteries, while extracranial vertebral arteries are better diagnosed using contrast-enhanced MRA, which is less dependent on flow phenomena and more accurate in evaluating stenosis.

CT angiography is also highly accurate in evaluation vertebrobasilar vessels, but ionizing radiation and use of nephrotoxic contrast media make it less suitable both in elderly with renal insufficiency and young adults because of radiation exposure. Moreover, vessel wall calcification and beam-hardening artifacts due to dense bones or metal fillings sometimes cause strong CT-image degradation.

Smith (2015) conducted a study that looked into specific biological markers that correlate to Moyamoya disease. Some of the categories of these biomarkers include phenotypes - conditions commonly related to Moyamoya, radiographical markers for the diagnosis of Moyamoya, and proteins as well as cellular changes that occur in cases of Moyamoya.

Similar to Moyamoya Disease, there are conditions that are closely associated with Moyamoya Syndrome. Some of the more common medical conditions that are closely associated with Moyamoya Syndrome include trisomy 21 (Down's Syndrome), sickle cell disease, and neurofibromatosis type 1. There is also evidence that identifies hyperthyroidism and congenital dwarfing syndromes as two of the more loosely associated syndromes that correlate with the possibility of being diagnosed with Moyamoya Disease later in life.

There is also research that has shown that certain radiographic biomarkers that lead to the diagnosis of Moyamoya Disease have been identified. The specific radiographic markers are now considered an acceptable key component to Moyamoya Disease and have been added to the INternational Classification of Diseases (ICD). These biomarkers of Moyamoya are "stenosis of the distal ICA's up to and including the bifurcation, along with segments of the proximal ACA and MCA...dilated basal collateral vessels must be present" Some other common findings that have not been added to the classification index of those with Moyamoya Disease which are found using radiography involve very distinct changes in the vessels of the brain. These changes include newly formed vessels made to compensate for another change noted, ischemia and cerebrovascular reserve, both found on MRI. Functional changes include evidence of ischemia in vessels of the brain (ICA, ACA, MCA, specifically). It is important to also note that the radiographic biomarkers, in order to be classified as Moyamoya Disease, all findings must be bilateral. If this is not the case and the findings are unilateral, it is diagnosed as Moyamoya Syndrome.

There are also several protein biomarkers that have been linked to the Moyamoya Disease diagnosis. Although the sample size of the studies performed are small due to the rarity of the disease, the findings are indicative of a correlation between the disease and several specific protein biomarkers. Other studies have confirmed the correlation of Moyamoya and adhesion molecule 1 (ICAM-1) being increased as compared to normal vascular function counterparts Furthermore, it has been concluded that the localization of inflammatory cells suggests that the inflammation stimulus iteself may be responsible for the proliferation and occlusion in the ICA, ACA, and MCA found in those with Moyamoya Disease.

Diagnosis involves consideration of physical features and genetic testing. Presence of split uvula is a differentiating characteristic from Marfan Syndrome, as well as the severity of the heart defects. Loeys-Dietz Syndrome patients have more severe heart involvement and it is advised that they be treated for enlarged aorta earlier due to the increased risk of early rupture in Loeys-Dietz patients. Because different people express different combinations of symptoms and the syndrome was identified in 2005, many doctors may not be aware of its existence, although clinical guidelines were released in 2014-2015. Dr. Harold Dietz, Dr. Bart Loeys, and Dr. Kenneth Zahka are considered experts in this condition.

The diagnosis of moyamoya is suggested by CT, MRI, or angiogram results. Contrast-enhanced T1-weighted images are better than FLAIR images for depicting the leptomeningeal ivy sign in moyamoya disease. MRI and MRA should be performed for the diagnosis and follow-up of moyamoya disease. Diffusion-weighted imaging can also be used for following the clinical course of children with moyamoya disease, in whom new focal deficits are highly suspicious of new infarcts.

Proliferation of smooth muscle cells in the walls of the Moyamoya affected arteries has been found to be representative of the disease. A study of six autopsies of six patients who died from Moyamoya disease lead to the finding that there is evidence that supports the theory that there is a thickening, or proliferation, of the innermost layer of the vessels affected by Moyamoya. These vessels are the ACA (anterior cerebral artery), MCA (middle cerebral artery), and ICA (internal carotid artery). The occlusion of the ICA results in concomitant diminution of the "puff-of-smoke" collaterals, as they are supplied by the ICA.

Often nuclear medicine studies such as SPECT (single photon emission computerized tomography) are used to demonstrate the decreased blood and oxygen supply to areas of the brain involved with moyamoya disease. Conventional angiography provided the conclusive diagnosis of moyamoya disease in most cases and should be performed before any surgical considerations.

Dr. Darren B. Orbach, MD, PhD explains how the disease progresses as well as the role angiography plays in detecting the progression of Moyamoya in a short video

Diagnosis commonly occurs later in childhood and often occurs incidentally in asymptomatic patients or as a cause of visual impairment. The first symptoms are commonly found during routine vision screenings.

A number of examinations can be used to determine the extent of the syndrome and its severity. Fluorescein angiography is quite useful in diagnosing the disease, and the use of ultrasonography and optical coherence tomography (OCT) are helpful in confirming the disease. Neuro-ophthalmic examinations reveal pupillary defects (see Marcus Gunn Pupil). Funduscopic examinations, examinations of the fundus of the eye, allow detection of arteriovenous malformations. Neurological examinations can determine hemiparesis and paresthesias. Malformations in arteriovenous connections and irregular functions in the veins may be distinguished by fluorescein angiographies. Cerebral angiography examinations may expose AVMs in the cerebrum. MRIs are also used in imaging the brain and can allow visualization of the optic nerve and any possible atrophy. MRI, CT, and cerebral angiography are all useful for investigating the extent and location of any vascular lesions that are affecting the brain. This is helpful in determining the extent of the syndrome.

Most people with Takayasu’s arteritis respond to steroids such as prednisone. The usual starting dose is approximately 1 milligram per kilogram of body weight per day (for most people, this is approximately 60 milligrams a day). Because of the significant side effects of long-term high-dose prednisone use, the starting dose is tapered over several weeks to a dose which controls symptoms while limiting the side effects of steroids.

Promising results are achieved with mycophenolate and tocilizumab. If treatment is not kept to a high standard, long-term damage or death can occur.

For patients who do not respond to steroids may require revascularization, either via vascular bypass or angioplasty and stenting. Outcomes following revascularization vary depending on the severity of the underlying disease

If the medical history and the actual exam of the hemangioma look typical for PHACE Syndrome, more tests are ordered to confirm the diagnosis. These tests may include:

- Ultrasound

- Magnetic resonance imaging (MRI)

- Magnetic resonance angiography of the brain (MRA)

- Echocardiogram

- Eye exam by an eye doctor

- Other tests may be needed for diagnosis and treatment

CREST is not easily diagnosed as it closely mimics symptoms of other connective tissue and autoimmune diseases. Diagnoses are usually given when a patient presents three or more of the five major clinical symptoms. Additionally, blood exams can be given to test for a positive ANAs and ACAs or skin biopsies can be given to help confirm a diagnosis.

CREST syndrome can be noted in up to 10% of patients with primary biliary cirrhosis.

Patients should discuss with their physician possible causes for their VBI symptoms. As discussed above, postural changes, exercise, and dehydration are some of the likely culprits. Treatment usually involves lifestyle modifications. For example, if VBI is attributed mainly to postural changes, patients are advised to slowly rise to standing position after sitting for a long period of time. An appropriate exercise regimen for each patient can also be designed in order to avoid the excessive pooling of blood in the legs. Dehydrated patients are often advised to increase their water intake, especially in hot, dry climates. Finally, when applicable, patients are often advised to stop smoking and to control their hypertension, diabetes, and cholesterol level.

In the event that a patient suffers a “drop attack,” and especially for the elderly population, the most important action is to be evaluated for associated head or other injuries. To prevent drop attacks, patients are advised to “go to the ground” before the knees buckle and shortly after feeling dizzy or experiencing changes in vision. Patients should not be concerned about the social consequences of suddenly sitting on the floor, whether in the mall or sidewalk, as such actions are important in preventing serious injuries.

Sometimes, to prevent further occlusion of blood vessels, patients are started on an antiplatelet agent (aspirin, clopidogrel, or aspirin/dipyridamole) or sometimes an anticoagulant (warfarin) once hemorrhage has been excluded with imaging.

For treatment of vertebrobasilar stenosis due to atherosclerosis, researchers from Stanford University found that intracranial angioplasty can be performed with an annual stroke rate in the territory of treatment of 3.2% and 4.4% for all strokes, including periprocedural events. Randomized control trials need to be performed.

In addition to evaluating the symptoms above, the health care provider may find decreased or no blood pressure in the arm or leg.

Tests to determine any underlying cause for thrombosis or embolism and to confirm presence of the obstruction may include:

- Doppler ultrasound, especially duplex ultrasonography. It may also involve transcranial doppler exam of arteries to the brain

- Echocardiography, sometimes involving more specialized techniques such as Transesophageal echocardiography (TEE) or myocardial contrast echocardiography (MCE) to diagnose myocardial infarction

- Arteriography of the affected extremity or organ Digital subtraction angiography is useful in individuals where administration of radiopaque contrast material must be kept to a minimum.

- Magnetic resonance imaging (MRI)

- Blood tests for measuring elevated enzymes in the blood, including cardiac-specific troponin T and/or troponin I, myoglobins, and creatine kinase isoenzymes. These indicate embolisation to the heart that has caused myocardial infarction. Myoglobins and creatine kinase are also elevated in the blood in embolisation in other locations.

- Blood cultures may be done to identify the organism responsible for any causative infection

- Electrocardiography (ECG) for detecting myocardial infarction

- Angioscopy using a flexible fiberoptic catheter inserted directly into an artery.

As there is no known cure, Loeys–Dietz syndrome is a lifelong condition. Due to the high risk of death from aortic aneurysm rupture, patients should be followed closely to monitor aneurysm formation, which can then be corrected with interventional radiology or vascular surgery.

Previous research in laboratory mice has suggested that the angiotensin II receptor antagonist losartan, which appears to block TGF-beta activity, can slow or halt the formation of aortic aneurysms in Marfan syndrome. A large clinical trial sponsored by the National Institutes of Health is currently underway to explore the use of losartan to prevent aneurysms in Marfan syndrome patients. Both Marfan syndrome and Loeys–Dietz syndrome are associated with increased TGF-beta signaling in the vessel wall. Therefore, losartan also holds promise for the treatment of Loeys–Dietz syndrome. In those patients in which losartan is not halting the growth of the aorta, irbesartan has been shown to work and is currently also being studied and prescribed for some patients with this condition.

If an increased heart rate is present, atenolol is sometimes prescribed to reduce the heart rate to prevent any extra pressure on the tissue of the aorta. Likewise, strenuous physical activity is discouraged in patients, especially weight lifting and contact sports.

A selective coronary angiogram is the most common method to diagnose the condition, although it is sometimes not recognised until after death. Intravascular ultrasound (IVUS) is also used as it is able to more easily differentiate the condition from atherosclerotic disease.

70% of patients with carotid arterial dissection are between the ages of 35 and 50, with a mean age of 47 years.

The treatment for Bonnet–Dechaume–Blanc syndrome is controversial due to a lack of consensus on the different therapeutic procedures for treating arteriovenous malformations. The first successful treatment was performed by Morgan et al. They combined intracranial resection, ligation of ophthalmic artery, and selective arterial ligature of the external carotid artery, but the patient did not have retinal vascular malformations.

If lesions are present, they are watched closely for changes in size. Prognosis is best when lesions are less than 3 cm in length. Most complications occur when the lesions are greater than 6 cm in size. Surgical intervention for intracranial lesions has been done successfully. Nonsurgical treatments include embolization, radiation therapy, and continued observation. Arterial vascular malformations may be treated with the cyberknife treatment. Possible treatment for cerebral arterial vascular malformations include stereotactic radiosurgery, endovascular embolization, and microsurgical resection.

When pursuing treatment, it is important to consider the size of the malformations, their locations, and the neurological involvement. Because it is a congenital disorder, there are not preventative steps to take aside from regular follow ups with a doctor to keep an eye on the symptoms so that future complications are avoided.

Blue toe syndrome is a situation that may reflect atherothrombotic microembolism, causing transient focal ischaemia, occasionally with minor apparent tissue loss, but without diffuse forefoot ischemia. The development of blue or violaceous toes can also occur with trauma, cold-induced injury, disorders producing generalized cyanosis, decreased arterial flow, impaired venous outflow, and abnormal circulating blood.

The terms "blue toe syndrome", "grey toe syndrome" and "purple toe syndrome" are sometimes used interchangeably.

Studies may include echocardiography, thoracic and abdominal CT or MRI, peripheral arterial run off imaging studies, hypercoagulopathy labs, and interrogation of syndromes that lead to peripheral vascular pathology.