Small bowel hemorrhage: angiographic localization and intervention

Occult bleeding in the small bowel was localized with mesenteric angiography in 64 patients. Two groups of patients were identified. In the first group comprising 38 patients, bleeding sites were localized by the demonstration of contrast extravasation. In the second group of 26 patients, there was no extravasation. However, other angiographic findings suggested the source of bleeding. No active bleeding was necessary for a positive study in the second group. We conclude that in patients with suspected occult small bowel hemorrhage, mesenteric angiography helps localize the bleeding site. Clinically active bleeding is not always necessary, as angiographic findings other than extravasation may localize the source of hemorrhage.

MR gated subtraction angiography: evaluation of lower extremities

We report the first clinical experience with a new method for projective imaging of blood vessels (angiography) using magnetic resonance. Vascular contrast is produced noninvasively by the phase response of moving protons. Diastolic and systolic gated images produce, respectively, flow signal and flow void; the difference image is a map of the pulsatile flow: an arteriogram. Preliminary studies are presented of the lower extremities of one healthy volunteer and four patients (one each with occlusive disease, soft-tissue tumor, arteriovenous malformation, and venous femoral-popliteal graft). Patient data are compared with accompanying conventional arteriograms, and the new method is discussed.

Evaluation of optimized biplane pulmonary cineangiography

Biplane pulmonary cineangiograms utilizing a short cine pulse width and automatic brightness control were performed in 47 patients during normal respiration. The diagnostic quality of the arteriograms was categorized as good in 33 patients, fair in 12 patients, and poor in two patients. Of the 18 patients in whom pulmonary emboli were identified, cineangiography displayed certain diagnostic features to advantage, including motion of emboli in ten and respiratory scissoring of vessels overcoming vascular superimposition in three. Optimized pulmonary cineangiography is an acceptable alternative to serial film pulmonary angiography for the diagnosis of pulmonary embolism.

Projective imaging of pulsatile flow with magnetic resonance

Noninvasive angiography with magnetic resonance is demonstrated. Signal arising in all structures except vessels that carry pulsatile flow is eliminated by means of velocity-dependent phase contrast, electrocardiographic gating, and image subtraction. Background structures become in effect transparent, enabling the three-dimensional vascular tree to be imaged by projection to a two-dimensional image plane. Image acquisition and processing are accomplished with entirely conventional two-dimensional Fourier transform magnetic resonance imaging techniques. When imaged at 0.6 tesla, vessels 1 to 2 millimeters in diameter are routinely detected in a 50-centimeter field of view with data acquisition times less than 15 minutes. Studies of normal and pathologic anatomy are illustrated in human subjects.

The intestinal tract

In this chapter, we have considered angiographic applications for diagnosis and management of patients with gastrointestinal bleeding and intestinal ischaemia. For patients with upper gastrointestinal bleeding, diagnostic angiography should be performed only when and if endoscopy is not available or non-contributory. For therapeutic purposes, angiography is applied in patients who continue to bleed despite conservative measures and intervention becomes unavoidable. Therapeutic interventions include the intra-arterial infusion of vasopressin and/or transcatheter embolization. In patients with rectal bleeding the addition of radionuclide studies has reduced the number of negative arteriographic examinations. We currently use the radionuclide studies only as a guide to whether active bleeding is present or not. If the radionuclide test is negative, we do not perform angiography. If it is positive we proceed with angiography in order to confirm localization and control bleeding with an intervention. For patients with rapid bleeding who are haemodynamically unstable we bypass nuclear medicine and proceed directly with angiography. In patients with suspected intestinal ischaemia, angiography is the only means of deciding whether ischaemia is of the occlusive or the non-occlusive form. Mesenteric vascular occlusions are treated surgically while low flow states are managed with mesenteric artery infusions of papaverine. Angioplasty has been and can be applied in patients with mesenteric arterial stenoses and symptoms of chronic intestinal ischaemia.

Equipment choices, technical aspects and pitfalls of percutaneous transluminal angioplasty

Previously published papers on percutaneous transluminal angioplasty (PTA) have emphasized results rather than techniques. This review deals with equipment choices, technical aspects and pitfalls observed during the first 200 PTAs at the Brigham and Women's Hospital. Specific topics discussed include: (1) catheters kept in stock in the laboratory, (2) choice of approach and entry into the artery, (3) techniques for crossing stenoses, (4) dilatation of the lesion, (5) drugs used during the procedure, and (6) proper performance and interpretation of the postangioplasty arteriogram.