Although some types of congenital C1 arch anomalies are rare, type A defects are relatively common radiological findings that are unreported approximately 45% of the time. Based on the significant association between the anterior and posterior arch defects, we propose possible mechanisms for the formation of the bipartite atlas.

We report a rare case of gadolinium contrast extravasation in a rapidly expanding basal ganglia hemorrhage on magnetic resonance imaging (MRI). Contrast extravasation within an intracerebral hematoma (ICH) on computed tomography (CT) angiography has been described as the “spot sign” and is a well-known indicator of active bleeding; however, contrast extravasation has seldom been reported on MRI. In this case, a 61-year-old female inpatient developed acute left hemiparesis and dysarthria on her third day of hospital admission. An initial noncontrast head CT showed an ICH, increasing in size on the follow-up CT study, and a subsequent MRI brain without and with contrast demonstrated multiple round collections of active bleeding at the margins of the hematoma on the postcontrast images. A CT angiogram performed following the MRI confirmed contrast extravasation along the margins of the hematoma. This case is unique as it demonstrates the “spot sign” with MRI, and the multiple foci of active bleeding identified with MRI support the “avalanche” hypothesis, which proposes that the initial expanding ICH leads to additional arterial ruptures and propagation of bleeding.

Internal hernias involve herniation of viscera into an abdominal compartment through a defect in the mesentery or peritoneum. Herniation may occur through normal anatomic structures or through pathologic defects secondary to congenital abnormality, inflammation, trauma, or surgery. Patients with an internal hernia most commonly present with acute bowel obstruction. While internal hernia is an uncommon cause of bowel obstruction, making up approximately 0.2-0.9% of cases (Choi, 2017), the incidence is increasing due to greater use of techniques such as Roux-en-Y for liver transplant and gastric bypass. There are multiple types of internal hernia, including paraduodenal, Foramen of Winslow, sigmoid mesocolon, pericecal, transmesenteric, transomental, supravesical, and pelvic. We present a case in which a transverse colon epiploic appendage adhesion to the ascending colon mesentery resulted in a closed loop obstruction mimicking a pericecal internal hernia. Radiologists should be aware of the imaging findings of closed loop obstruction related to internal hernia and maintain a high index of suspicion in patients with history of prior abdominal surgery presenting with bowel obstruction. It is useful for radiologists to understand that adhesions may result in internal hernias, which mimic the classically described categories.

ZusammenfassungPeriphere arterielle Verschlüsse lassen sich mittels der arteriellen digitalen Subtraktionsangiographie (DSA) darstellen. Methode: In der vorliegenden Fallstudie verglichen wir die invasive Technik der arteriellen DSA mit dem nichtinvasiven zweidimensionalen Laser-Doppler- Perfusion-Imaging. Ergebnis: Bei 2 Patienten mit Thrombangitis obliterans entsprachen den Arterienabbrüchen Areale mit verminderten Fluxwerten im LDPIBild. Eine Patientin mit Livedo-Vaskulitis zeigte hingegen eine vermehrte Gefäßkontrastierung und vermehrten Kontrastmittelfluß in der DSA, aber Areale mit verminderten Fluxwerten im LDPI-Bild. Histologisch entsprachen den offenen Lumina der subkutanen Arterien hingegen hyaline Thromben der korialen Arteriolen. Schlußfolgerung: Insgesamt erfaßt das LDPI offenbar selektiv die kutane Perfusion. Da das Verfahren nicht invasiv ist, ermöglicht es wiederholte Verlaufskontrollen.