The case for radioprotective eyewear/facewear. Practical implications and suggestions.

Numerous eyeglass lens materials have been recommended for protection of radiologists' eyes from the cataractogenic effect of radiation during fluoroscopic procedures. For the most part, these lenses coincidentally attenuate x-ray beams because they contain elements of high atomic number that are added to increase refractive index. With a bean hardened to simulate scatter, direct transmission ratios were measured for 32 commercially available lens materials. Scatter to the eye, both through and around the glass lenses and secondary scatter to the eye from the radiologist's head, was determined with lenses mounted on a head phantom and a 1-cm3 ion chamber in the position of the eye. Transmission ratios for the various lenses ranged from 3% to 98% for an 80 kVp x-ray beam (HVL = 4.5 mm Al). Measurements with the head phantom in place show that secondarily scattered radiation from the fluoroscopist's head contributes significantly to ocular exposure. Optimal radiation protection of the eyes during fluoroscopy depends not only on eyeglasses with leaded glass, but also on shielding of sufficient size and shape to reduce exposure to the surrounding head.

The middle mesenteric artery.

Angiography was performed in a 70-year-old man because of a recurrence of massive hemochezia. The angiogram demonstrated a third mesenteric artery, arising from the aorta between the superior and inferior mesenteric arteries and supplying the splenic flexure. Although many variations of colonic arterial supply have been described, those involving vessels originating from the aorta separate from the celiac, superior mesenteric, or inferior mesenteric arteries are extremely rate.

Meckel's diverticula: angiographic diagnosis in patients with non-acute hemorrhage and negative scintigraphy.

Meckel's diverticula were detected by mesenteric angiography in 2 patients with unexplained gastrointestinal bleeding following negative barium, endoscopic, and scintigraphic evaluation. Abnormal, irregular, arterial branches supplied by an elongated, nonbranching ileal artery and an associated capillary stain were present in each case. Since neither diverticulum was bleeding at the time of angiography, focal contrast extravasation was not present. Superselective magnification angiography, evacuation of contrast from the urinary bladder, and careful patient positioning significantly improved the visibility of these lesions. Visceral angiography performed with meticulous attention to technical detail can be diagnostic of Meckel's diverticulum, even in the absence of acute hemorrhage.

Tube tamponade: potential pitfall in angiography of arterial hemorrhage associated with percutaneous drainage catheters.

Diagnostic angiography performed to search for a source of hemorrhage in three patients with percutaneous transhepatic biliary catheters and one patient with a percutaneous nephrostomy catheter was initially unrewarding when performed with the drainage catheter in place. In each patient, removal of the drainage catheter resulted in severe pulsatile hemorrhage from the parenchymal tract and allowed angiographic localization of the bleeding site. Temporary control of the hemorrhage was then obtained by inflating an angioplasty balloon within the tract. Transcatheter embolotherapy provided definitive control of bleeding in three patients. When initial angiographic evaluation for bleeding in patients with percutaneous biliary and nephrostomy catheters fails to depict a source, the study should be repeated immediately after removal of the drainage catheter. Because hemorrhage can be severe once tamponade is relieved, the drainage catheter should be withdrawn over a guide wire so that a tamponading catheter can be rapidly reinserted to control hemorrhage until more definitive therapy is undertaken.

Chronic arteriovenous fistulas masquerading as arteriovenous malformations: diagnostic considerations and therapeutic implications.

Arteriovenous fistulas (AVFs) and arteriovenous malformations (AVMs) may be difficult to differentiate angiographically, and this differentiation has important therapeutic implications. In five cases of chronic AVF, four originally misdiagnosed as AVMs, superselective angiography enabled the correct diagnosis. In two plantar arch fistulas, the technique was further enhanced by manual compression of arterial inflow to decrease the rate of blood flow through the fistula. All five AVFs were successfully occluded. The authors conclude that AVFs and AVMs can be distinguished by means of the appropriate angiographic techniques.