Focal small bowel lesions present a diagnostic challenge for both the radiologist and gastroenterologist. Both the detection and characterization of small bowel masses have greatly improved with the advent of multidetector CT enterography (MD-CTE). As such, MD-CTE is increasingly utilized in the workup of occult gastrointestinal bleeding. In this article, we review the spectrum of focal small bowel masses with pathologic correlation. Adenocarcinoma, the most common primary small bowel malignancy, presents as a focal irregular mass occasionally with circumferential extension leading to obstruction. Small bowel carcinoid tumors most commonly arise in the ileum and are characterized by avid enhancement and marked desmoplastic response of metastatic lesions. Aneurysmal dilatation of small bowel is pathognomonic for lymphoma and secondary findings of lymphadenopathy and splenomegaly should be sought. Benign small bowel masses such as leiomyoma and adenoma may be responsible for occult gastrointestinal bleeding. However, primary vascular lesions of the small bowel remain the most common cause for occult small bowel gastrointestinal bleeding. The arterial phase of contrast obtained with CTE aids in recognition of the vascular nature of these lesions. Systemic conditions such as Peutz-Jeghers syndrome and Crohn's disease may be suggested by the presence of multiple small bowel lesions. Lastly, potential pitfalls such as ingested material should be considered when faced with focal small bowel masses.
Gastrointestinal stromal tumors (GISTs), the most common mesenchymal tumors of the gastrointestinal tract, are a relatively recently described entity. Most exhibit a mutated tyrosine kinase receptor gene and in some capacity are treated by tyrosine kinase inhibitors. GISTs can occur across the age spectrum but are more common in patients older than 40 years. They exhibit a wide range of clinical presentations and imaging characteristics. All patterns of enhancement on contrast enhanced computed tomography (CECT) can be seen with GISTs, including hypoenhancing, isoenhancing, and hyperenhancing tumors. They can be large or small, endoluminal or exophytic. Clinical presentations include asymptomatic patients, nonspecific symptoms, obstruction, and bleeding. Bleeding can take the form of slow, intraluminal GI bleeding or massive intraperitoneal bleeding secondary to rupture and can be seen regardless of the enhancement pattern. Some can cavitate, ulcerate, rupture or cause fistulae. The radiologist's knowledge of the variety of combinations of presentations can narrow the differential diagnosis and ultimately lead to faster diagnosis and treatment.
Vascular interventional radiology procedures are relatively safe compared with analogous surgical procedures, with overall major complication rates of less than 1%. However, major vascular injuries resulting from these procedures may lead to significant morbidity and mortality. This review will discuss the etiology, clinical presentation, diagnosis, and management of vascular complications related to percutaneous vascular interventions. Early recognition of these complications and familiarity with treatment options are essential skills for the interventional radiologist.
We will review and illustrate the multiple advantages of ultrasound as an image guidance tool, including real-time vessel visualization, multiplanar capability, portability/availability, and decreased procedure time and cost.We will demonstrate the unique advantages of the use of this imaging modality in the biopsy of small parenchymal lesions particularly those that are not visible with unenhanced computed tomography (CT) or not persistently visible with contrast-enhanced CT or those lesions not readily accessible by CT guidance, the use of direct probe compression to displace bowel away from biopsy targets, the use of direct probe compression to staunch intraprocedural bleeding observed with real-time visualization to minimize postprocedural bleeding complications, and the ability to biopsy masses in pediatric patients as a function of the inherent lack of ionizing radiation.Finally, we will review and illustrate how the use of preprocedural lesion characterization with ultrasound at times can serve as a problem-solving tool providing an alternative and reasonably confident diagnosis and thus avoiding unnecessary procedures and associated potential risks.
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