64-row MDCT review of anatomic features and variations of the normal greater omentum

The omental free flap and flow-through flap: pre-operative evaluation of right gastro-omental artery on multidetector computed tomography

BACKGROUND

The gastro-omental artery (GOA) and the greater omentum are nowadays commonly used in many reconstructive surgeries, including cardiac, vascular, and plastic surgery. There are cases in which the GOA is found to be unsuitable only after partial harvesting following an upper laparotomy, and an improved method of pre-operative evaluation is required to eliminate the need for intraoperative small laparotomy.

METHODS

Multidetector computed tomography was performed for 30 consecutive patients admitted for lower limb ischemia in a routine pre-operative evaluation of lower limb peripheral arterial disease (PAD). The origin of the GOA was checked on coronal and sagittal slices, its pathway was identified on the three-dimensional rendering. We assessed length and mean diameter of the distal and proximal right GOA, and the mean distances between the origins of GOA and the omental branches. Finally, we report one case of omental flow-through flap.

RESULTS

30 patients were included in our study. Routine pre-operative MDCT during lower limb PAD workup enabled identification of GOA in all cases. The mean internal diameter of the GOA at its origin was 3.3 mm (± 3.3). The mean internal diameter of the distal GOA was 1.26 mm (± 0.3). At least one omental descending branch was detected in every case and in 63% (19 patients) at least two branches were visualized.

CONCLUSION

Routine pre-operative angio-MDCT imaging is an effective tool to assess precisely the different anatomical properties of the GOA. This exam could be useful for both diagnosis of lower limb PAD and evaluation of the GOA suitability for flow-through flap lower limb revascularisation.

Intra-abdominal fat. Part I. The images of the adipose tissue localized beyond organs

Unaltered fat is a permanent component of the abdominal cavity, even in slim individuals. Visceral adiposity is one of the important factors contributing to diabetes, cardiovascular diseases and certain neoplasms. Moreover, the adipose tissue is an important endocrine and immune organ of complex function both when normal and pathological. Its role in plastic surgery, reconstruction and transplantology is a separate issue. The adipose tissue has recently drawn the attention of research institutes owing to being a rich source of stem cells. This review, however, does not include these issues. The identification of fat is relatively easy using computed tomography and magnetic resonance imaging. It can be more difficult in an ultrasound examination for several reasons. The aim of this paper is to present various problems associated with US imaging of unaltered intra-abdominal fat located beyond organs. Based on the literature and experience, it has been demonstrated that the adipose tissue in the abdominal cavity has variable echogenicity, which primarily depends on the amount of extracellular fluid and the number of connective tissue septa, i.e. elements that potentiate the number of areas that reflect and scatter ultrasonic waves. The normal adipose tissue presents itself on a broad gray scale: from a hyperechoic area, through numerous structures of lower reflection intensity, to nearly anechoic regions mimicking the presence of pathological fluid collections. The features that facilitate proper identification of this tissue are: sharp margins, homogeneous structure, high compressibility under transducer pressure, no signs of infiltration of the surrounding structures and no signs of vascularization when examined with the color and power Doppler. The accumulation of fat tissue in the abdominal cavity can be generalized, regional or focal. The identification of the adipose tissue in the abdominal cavity using ultrasonography is not always easy. When in doubt, the diagnostic process should be extended to include computed tomography or magnetic resonance imaging, or sometimes biopsy (preferably the core-needle one).

Omental whirl associated with bilateral inguinal hernia: a case report

Introduction

Torsion of the omentum is a rare cause of abdominal pain. It is clinically similar to common causes of acute surgical abdomen and is often diagnosed during surgery. Inguinal hernia is a common condition but not frequently related with torsion of the omentum.

Case presentation

A 40-year-old Caucasian man came to our emergency department with abdominal pain of the left quadrant and abdominal distension for 2 days. His medical history included an untreated left inguinal hernia in the last year. Computed tomography revealed densification of mesocolon with left omentum “whirl” component and other signs of omental torsion. During an exploratory laparoscopy, a wide twist of his omentum with necrotic alterations that extended to the bilateral inguinal hernial content was observed. Omentectomy and surgical repair of bilateral inguinal hernia were performed.

Conclusions

Torsion of the omentum is a rare entity and usually presents a diagnostic challenge. The use of abdominal computed tomography can help diagnosing torsion of the omentum preoperatively and, thus, prevents a surgical approach. Nonetheless, some cases of torsion of the omentum require surgical repair. Accordingly, a laparoscopic approach is minimally invasive and efficient in performing omentectomy.

Omental vascular pedicle sign: multidetector CT finding useful for diagnosis of an omental mass

OBJECTIVE

To describe multidetector CT findings of "omental vascular pedicle" sign.

MATERIALS AND METHODS

"Omental vascular pedicle" sign was defined as dilated omental vein associated with a mass located in omentum and was observed in 7 patients (5 women, 2 men). Mean age was 45 years. CT examinations and patient records were retrospectively reviewed. CT images were obtained by 16-MDCT (n = 1) and 64-dual source MDCT (n = 6). Curved planar and volume rendered images were reconstructed from axial images. Diameter of omental vein and drainage site were recorded. Images were evaluated by 2 radiologists in consensus.

RESULTS

Pathologic diagnosis of patients with "omental vascular pedicle sign" was omental angiosarcoma (n = 1), endometrial adenocarcinoma (n = 2), ovarian serous adenocarcinoma (n = 2), mixed gonadal tumor (n = 1), malignant peripheral sheath tumor (n = 1). In 5 patients, omental vein drained into splenic vein and in 2 patients it drained into right gastroepiploic vein. Mean size of omental masses associated with omental vascular pedicle was 7.1 × 4.5 cm (range 15 × 11 cm to 2.7 × 1.6 cm). Mean diameter of omental vein was 3.1mm (range 6-1.5mm). Diameter of the omental vein increased with the increasing size of omental masses and Pearson's correlation coefficient was 0.99.

CONCLUSION

"Omental vascular pedicle sign" can be helpful to objectively diagnose omental masses in patients with primary and metastatic omental tumors.