Lesion Mural

Cholesterol embolization is thought to occur after removal of mural thrombi covering atherosclerotic plaques leading to direct exposure of the soft lipid-laden core of these plaques to the arterial circulation. The contents of the soft lipid core, including crystallized cholesterol, shower the downstream circulation. Cholesterol crystals are impervious to dissolution or lysis and they lodge in small arterioles, causing obstruction. Cholesterol embolization shortly after thrombolytic treatment is characterized by livedo reticularis or multiple necrotic lesions of the skin of both legs (7) but can also be associated with... 

The complicated lesion is associated with occlusive disease the contents of the fibrous plaque become calcified and are altered as a result of hemorrhage, cell necrosis, and mural thrombosis. 

Other Mesenchymal Lesions Presenting as Mural Masses... 

Fig. 9.4. Medial displacement of the iliac vessels. Transaxial CT in a patient with sonographically suspected bilateral ovarian cancer. Bilateral cystic lesions (asterisks) with mural thickening are simulating ovarian lesions. The displacement pattern of the iliac vessels, however, is typical for an origin from the pelvic sidewalls. The lesions present bilateral bursitis iliopectinea in a patient with rheumatoid arthritis...

Fig. 9.31. Collision tumor of the ovary. CT at the level of the mid pelvis in a 65-year-old woman with sonographically suspected ovarian cancer. A cystic right adnexal mass is demonstrated showing multiple thin septa-tions and a 3-cm lesion with fat density and mural calcifications (asterisk). Pathologically, a collision tumor composed of a benign mucinous cystadenoma and a benign dermoid was diagnosed...

Future Advances in Image Display Techniques Different Categories of Colorectal Morphologies 76 Focal Polypoid Lesions (r/o stool) 76 Pedunculated Lesions 79 Sessile/Flat Lesions (r/o thick or confluent Folds) 79 Advanced Mural Lesions (r/o collapse) 81 Standardization of Reporting of Clinically Significant Colorectal Findings 82 References 85... 

There are common types of colorectal morphologies evaluated in CT colonography. These include the focal polypoid lesion, pedunculated lesion, flat or sessile lesion and advanced mural lesions. This section will describe these morphologies and their corresponding false positive counterparts. The differential application of 2D and 3D image displays to assess these morphologies will also be reinforced. 

CT colonography has reliably shown high sensitivity to detect advanced mural lesions (Fig. 7.9). A potential challenge in CT colonography is the discernment between an advanced mural lesion of advanced cancer from an area of focal collapse with relative wall thickening (often seen at points of flex-... 

The importance of 2D MPR with soft tissue settings (window 400, level 10) needs to be emphasized with these types of lesions. Whether this is subtle mural thickening or advanced, the 2D MPR views give valuable information of the mural relationships, which extend beyond the lumenography of the 3D fly-through (Fig. 7.11). In addition the 3D transparency view, which simulates the barium enema, can be a powerful view to display the lesion for others to appreciate the size and location of the cancer. 

Fig. 7.9a-d. Advanced mural lesion (arrows) a prone non-contrast axial 2D MPR demonstrates advanced mural lesion b supine contrast enhanced axial 2D MPR shows enhancing mass immersed in fluid c 3D volume rendered intraluminal view demonstrates mural mass of cancer d 3D transparency view shows classic apple-core lesion... 

Fig. 7.10a,b. Advanced mural lesion (arrows) vs collapse (arrowheads) a sagittal 2D MPR view shows mural thickening of advanced cancer vs area of luminal collapse without mural thickening b 3D edge enhanced view also demonstrates these two areas... 

Fig. 7.1 la-e. Subtle advancedmurallesion with polypoid (white arrow) and stalk (white arrowheads) components, along with infiltrative T3 mural invasion (open arrows), best seen in soft tissue MPR views a supine axial 2D MPR (W 1500, L -200) does not demonstrate lesion well, compared to b b supine axial 2D MPR in soft tissue settings (W 400, L20) best demonstrates the polypoid component and flat soft tissue mural infiltration c prone axial 2D MPR shows immersed lesion requires a narrower soft tissue window setting (W 900, L 300) to see through the fluid d optimized 3D view shows polypoid and infiltrative mural components (only seen retrospectively) e corresponding view at optical colonoscopy... 

Ionic tissues. We have infrequently encountered this occurrence. Close correlation with clinical history and clinical follow up and re-imaging or endoscopy after the episode has past is prudent. In our limited experience with this entity, contrast-enhancement may be helpful by demonstrating mural stratification and diverticula within the lesion (Fig. 14.15). 

Accompanying IMHs can be detected in nonenhanced scans and verify the penetrating character of the lesion. Furthermore, nonenhanced scans facihtate the therapeutically relevant differentiation between pseudoaneurysms as a comphcation of a PAU and a sacciform aortic aneurysm. Mural calcifications suggest an aneurysm. In the case of a spacious IMH or paraaortic hematoma, the differentiation between a ruptured aneurysm and a complicated PAU can be impossible. However, in both cases, an immediate therapeutic intervention is indicated. Complications of a PAU, hke AD, formation of a pseudoaneurysm, or aortic rupture can all be detected or excluded in the same scan. 

Gastric carcinomas may present as a focal area of mural thickening with or without ulceration, or as a generalized mural thickening. Sometimes they present as a polypoid lesion. 

Fig. 9.17. a Intraluminal villous adenoma. CECT shows a soft-tissue polypoid mass with a small pedicle, arising from the medial aspect of the descending duodenum, with no mural thickening or extraduodenal disease, b Malignant villous tumor of the duodenum. Note the extensive carpetlike lesion involving most of the inferior duodenal flexure as well as the liver metastasis (c)... 

---