Imaging Pearls ❯ Chest ❯ Vascular Malformations and AVMs
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- Interruption of the inferior vena cava: facts
- Interruption of the inferior vena cava (IVC) with azygos continuation is a rare congenital anomaly, in which the IVC is interrupted below the hepatic vein and venous return beyond this point is restored by the dilated azygos and hemiazygos veins draining into the superior vena cava.
- this congenital anomaly could be isolated, but often it is part of more complex syndrome including for example cardiac malformations, asplenia, and polysplenia syndrome. Interruption of the IVC with azygos continuation is the second most common abnormality associated with polysplenia syndrome - “The polysplenic syndrome is defined by the presence of multiple spleens, usually numbering between two and six. In contrast to accessory spleens, the spleens are of uniform size. Accessory spleens usually measure between 1 and 2 cm and are not considered as a form of the polysplenic syndrome. Splenosis, an acquired rather than congenital condition that arises in the context of traumatic splenic rupture, can be ruled out by patient history.”
Polysplenia syndrome
B. De La Villeon et al.
Journal of Visceral Surgery,Volume 148, Issue 5,2011, Pages e395-e396, - "Splenosis typically consists of multiple small implants of splenic tissue; it can mimic peritoneal carcinomatosis or endometriosis depending on the clinical context.”
Polysplenia syndrome
B. De La Villeon et al.
Journal of Visceral Surgery,Volume 148, Issue 5,2011, Pages e395-e396, - "The syndrome of polysplenia is often accompanied by a variable spectrum of visceral and vascular developmental anomalies. It is rarely diagnosed in adults. While it is estimated that 2.5/100,000 infants are born with this anomally, fewer than 5% are still alive at five years of age due to the associated severe cardiac anomalies.The syndrome is associated with multiple congenital malformations that may involve the solid organs and digestive tube of the abdominal cavity, the heart, or the great vessels. The diagnosis is often made during surgical exploration for an associated cardiac or digestive anomaly. Among the most common vascular anomalies are agenesis of the suprarenal inferior vena cava with persistent continuity of the azygos vein, and pre-duodenal position of the portal vein. Biliary atresia is found in nearly 50% of cases, common mesentery in more than 75% of cases, and an abbreviated or annular pancreas in 85–90% of cases.”
Polysplenia syndrome
B. De La Villeon et al.
Journal of Visceral Surgery,Volume 148, Issue 5,2011, Pages e395-e396 - “Anomalies include asplenia, the congenital absence of the spleen. This can be isolated or part of a clinical sequela of a broader syndrome such as Ivermark syndrome, a heterotaxy syndrome occurring in 1 in 10,000 to 40,000 cases. CT will show lack of spleen and Tc-99 red blood cell scan will show lack of uptake.”
MDCT Findings of Splenic Pathology
Sangster GP et al.
Current Problems in Diagnostic Radiology 2021 (in press)
- “Hereditary hemorrhagic telangiectasia(HHT),also known as Osler- Weber-Rendu disease, is an auto- somal dominant genetic disorder affecting 1 in 8000 people. HHT is known to be caused by at least three mutations: ENG (type I HHT) encoding endoglin; ACVRL1 (type II HHT) encoding activin receptorlike kinase 1 (ALK-1); and SMAD4, associated with juvenile polyposis. Clinically, HHT is diagnosed according to the Curaçao criteria, which include multiple mucocutaneous telangiectases, epistaxis, visceral arteriovenous malformations (AVMs), and a family history of HHT in a first-degree relative .”
CT Angiography Findings of Pulmonary Arteriovenous Malformations in Children and Young Adults With Hereditary Hemorrhagic Telangiectasia
Shin SM et al.
AJR 2020; 214:1369–1376 - "Pulmonary AVMs (PAVMs) are seen in as many as 49% of patients with HHT. Although serious complications are rare, PAVMs can lead to life-threatening events including massive hemorrhage from PAVM rupture and complications of right-to-left cardiac shunt, including pulmonary hypertension, paradoxic embolism with stroke, and cerebral abscess. PAVMs tend to be progressive with age. To prevent progression in size and the serious complications associated with PAVMs, early detection and intervention are critical.”
CT Angiography Findings of Pulmonary Arteriovenous Malformations in Children and Young Adults With Hereditary Hemorrhagic Telangiectasia
Shin SM et al.
AJR 2020; 214:1369–1376 - "The imaging findings of PAVM have been well described in adult chest CT studies and include presence of a feeding artery, a draining vein or veins, and an aneurysmal sac or nidus. A feeding artery larger than 3 mm is currently accepted as an indication for prophylactic embolization in an effort to reduce the risk of cerebral complications, although smaller lesions can be embolized if symptomatic.”
CT Angiography Findings of Pulmonary Arteriovenous Malformations in Children and Young Adults With Hereditary Hemorrhagic Telangiectasia
Shin SM et al.
AJR 2020; 214:1369–1376 - "The most common PAVMs in children and young adults with HHT were less ma- ture than those seen in adult populations. Use of MIP enabled more precise detec- tion of the afferent and efferent vessels. The highest grade in each patient had the strongest correlation with the severity of pulmonary right-to-left shunt. Unlike the situation in older adults, age was not an important factor in determining the severity of PAVMs in children and young adults. Even in patients without symptoms, PAVMs are noted in most patients with abnormal CE- TTE findings."
CT Angiography Findings of Pulmonary Arteriovenous Malformations in Children and Young Adults With Hereditary Hemorrhagic Telangiectasia
Shin SM et al.
AJR 2020; 214:1369–1376 - "Routine screening of all patients with HHT for PAVM is recom- mended, and contrast-enhanced transthoracic echocardiography (CE-TTE) and chest CT have been the primary imaging tools.”
CT Angiography Findings of Pulmonary Arteriovenous Malformations in Children and Young Adults With Hereditary Hemorrhagic Telangiectasia
Shin SM et al.
AJR 2020; 214:1369–1376
- Vascular Malformations and Hemangiomatosis Syndromes
- Blue rubber bleb nevus syndrome
- Proteus syndrome
- Klippel-Trenauney Sydrome
- Kasabach-Merritt syndrome - Proteus Syndrome: facts
- Hemihypertrophy, partial gigantism
- Vascular tumors and AVMs
- Lipomas and fatty tumor proliferation
- splenomegaly - Klippel-Trenaunay Syndrome: Facts
- Three key findings
– Port wine stain
– Abnormal vascular structures
– Osseous and soft tissue hypertrophy - Kasabach-Merritt Syndrome: facts
- Consumptive thrombocytopenia and coagulopathy
- Can lead to DIC
- May have large hepatic or splenic hemangioma
- Association with angiosarcoma and AVMs - Pulmonary Arteriovenous Malformations: Facts
- Congenital in origin
- 60-90% of patients have hereditary hemorrhagic telangiectasia (aka Rendu- Osler-Weber syndrome)