Morton A. Meyers

Pathogenesis of bleeding colonic diverticulosis.

The cause of bleeding was found in 8 of 10 cases of colonic diverticulosis associated with severe rectal hemorrhage by using arteriographic and microangiographic techniques to localize the site and serial histological sections to study the lesion. Strikingly consistent changes were identified. These are related to the characteristic angioarchitecture of colonic diverticula. These changes include asymmetric rupture of the vas rectum toward the lumen of the diverticulum precisely at its dome or antimesenteric margin; conspicuous eccentric intimal thickening of the vas rectum, often with medial thinning of duplication of the internal elastic lamina at and near the bleeding point; and general absence of diverticulitis. Control colonic diverticula demonstrated normal structures or, only occasionally, minimal eccentric intimal thickening in their associated vasa recta. This suggests that traumatic factors arising within the diverticular or colonic lumen induce asymmetric intimal proliferation and scarring of the associated vasa recta, predisposing to rupture and massive bleeding.

Secondary Neoplasms of the Bowel

Abstract On the basis of 107 cases, the authors applied and evaluated a practical classification in the roentgen analysis of secondary bowel neoplasms. A distinction was made between direct invasion, intraperitoneal seeding, and hematogenous metastases. Characteristic radiologic features are helpful in identification of the mode of dissemination and as indicators of the likely primary site. The role of anatomic relationships and mesenteric attachments, particularly in cases of direct invasion, is stressed. The distribution of seeding correlates with the known pathways of spread and localization of intraperitoneal fluid. The frequency and appearance of melanoma and breast embolic metastases are emphasized.

The Spread and Localization of Acute Intraperitoneal Effusions

Abstract Major routes of spread of intraperitoneal exudates and subsequent localizations of abscesses at sites remote from their source were determined primarily by peritoneography and selected clinical cases. Fluid ascends the right external paracolic gutter from the pelvic cavity to enter Morrisons pouch before progressing to the right subphrenic space. The phrenicocolic ligament restricts flow in either direction between the left paracolic gutter and perisplenic space. The mesenteric attachments themselves may serve as pathways for the spread of exudates. Extravasated pancreatic enzymes may pass down the length of the small-bowel mesentery to the ileocecal region.

Radiological features of the spread and localization of extraperitoneal gas and their relationship to its source. An anatomical approach.

Extraperitoneal gas may be produced by (a) perforation of the descending duodenum, sigmoid diverticula, or rectum, (b) pancreatic or perirenal infection, or (c) extraperitoneal gas of subdiaphragmatic origin and displays a characteristic spread and localization depending upon its source. The author describes the anatomy of the extraperitoneal fascial planes and compartments and discusses the basic roentgen features of extraperitoneal gas and its distinction from intraperitoneal collections.

Diffuse cavernous hemangioma of the colon in the Klippel-Trenaunay syndrome.

Large, infiltrative cavernous hemangiomas of the distal colon were present in 3 children with the Klippel-Trenaunay syndrome, 2 of whom are the subject of this report. The lesion is manifested clinically as intermittent rectal bleeding starting in the first 5 years of life. The radiographic features include (a) varicose lesions in the wall of the rectosigmoid, ranging from a network of distended submucosal veins to nodular defects, (b) narrowing of the rectum by the surrounding extramural portion of the hemangioma, and (c) phleboliths within the lesion. Inferior mesenteric angiography and sigmoidoscopy are useful for preoperative confirmation. The occurrence of visceral hemangiomas in the Klippel-Trenaunay syndrome and its relevant diagnostic and therapeutic implications are discussed.

Radiologic features of extraperitoneal effusions. An anatomic approach.

Abstract Criteria for radiological diagnosis of specific compartmentalization of extraperitoneal fluid and its possible sources were developed by (a) determining pathways of extraperitoneal fluid flow and establishing preferential routes of spread from various sites; (b) establishing fascial boundaries which direct and compartmentalize extraperitoneal fluid collections; and (c) defining the role of peritoneal reflections in the passage of exudates. The correlation of the distribution of fluid with the extraperitoneal fascial planes is based on cross-sectional planes derived from frozen cadavers, postmortem injection studies, and selected clinical cases in various disease states.

The angioarchitecture of colonic diverticula. Significance in bleeding diverticulosis.

The intramural distribution of the vasa recta of the colon and particularly their relationship to diverticula were investigated in a group of operative and postmortem specimens using intra-arterial barium-gelatin injections, followed by high resolution radiography, microdissections, and histologic sections. Detailed study demonstrated a large arterial branch arching immediately over the dome of the diverticulum. Multiple short branches are displaced intimately around the body and neck of the sac. A pathogenetic relationship between bleeding colonic diverticulosis and the distinctive angioarchitecture is strongly indicated.

Necrotizing Enterocolitis with Pneumatosis Intestinalis in Systemic Lupus Erythematosus and Polyarteritis

Pneumatosis intestinalis was encountered in association with fatal necrotizing enterocolitis in systemic lupus erythematosus (SLE) and polyarteritis nodosa. The radiologic identification of mottled, bubbly, and linear collections of intramural intestinal gas distinguish this ominous complication from benign pneumatosis cystoides intestinalis. In the setting of intestinal vasculitis due to SLE or polyarteritis nodosa, these characteristic radiologic features indicate necrotizing enterocolitis. Since corticosteroids may mask clinical progression of the intestinal lesion, radiologic evaluation is essential in the overall management of the patient with intestinal vasculitis.

Complications of fiberoptic Endoscopy. II. Colonoscopy.

Fiberoptic colonoscopy is being used increasingly for endoscopic visualization of the large intestine, particularly in the electrocautery removal of polypoid lesions. Complications may include bleeding, mesosigmoid hematoma, splenic avulsion, and impaction of the instrument, but the most common is perforation of the colon, which occurs in 0.4-1.9% of colonoscopic examinations. Radiological evaluation plays a critical role. Free intraperitoneal rupture may be clinically overlooked in an aged or infirm patient. Extraperitoneal perforation often results in delayed signs and symptoms. The demonstration of extraluminal gas documents perforation. Recent roentgen-anatomical studies of the characteristic distribution of extraperitoneal gas may permit precise localization of the site of colonic perforation on plain films.

Ascending retrocecal appendicitis.

Acute inflammation of an ascending retrocecal appendix with abscess formation produces distinctive roentgen signs characterized by irregular nodularity (often restricted to a specific haustral row) and spastic inflammatory changes, which may involve the posterolateral wall of the ascending colon anywhere along its length from the cecum to the hepatic flexure. Even if the appendix cannot be seen, its position may be inferred from the location of the ileocecal valve. Barium opacification of the appendix does not exclude the diagnosis of acute appendicitis. The appendix may demonstrate mass displacement, sinus tracts, or communication with the abscess cavity.