腹部脂肪坏死的临床和CT表现

腹部脂肪坏死是一种常见的病理改变,可引起腹部疼痛,与急腹症的表现相似;也可无症状而由机体其他病理生理变化而引发.腹部脂肪坏死实际上是脂肪组织因代谢或机械性原因发生变性的结果.常见的腹部脂肪坏死包括肠脂垂炎、大网膜梗死、创伤性或缺血性损伤所导致的局灶性脂肪坏死以及胰腺炎所导致的脂肪坏死.脂肪坏死作为一种相对常见的脂肪组织病变应为临床和影像医师所熟知.介绍腹部脂肪坏死和相关疾病的各种临床及CT表现.     

The CT appearances of ruptured abdominal aortic aneurysms

There is no place for investigative CT scans in patients who have the classical triad of abdominal aortic aneurysm rupture, namely excruciating abdominal pain or backache, a pulsatile mass and hypotension. These patients require immediate surgery. However, in the absence of this triad, CT scans play an important role in the diagnosis of abdominal aortic aneurysm rupture. The CT scan findings will dictate whether the patient requires immediate surgery as in the case of acute rupture, or, whether the surgery can be delayed up to 24 hours to allow for stabilisation and hydration, as in the case of subacute and chronic rupture.     

Massive ovarian edema,due to adjacent appendicitis

Massive ovarian edema is a benign clinical entity, the imaging findings of which can mimic an adnexal mass or ovarian torsion. In the setting of acute abdominal pain, identifying massive ovarian edema is a key in avoiding potential fertility-threatening surgery in young women. In addition, it is important to consider other contributing pathology when ovarian edema is secondary to another process. We present a case of a young woman presenting with subacute abdominal pain, whose initial workup revealed marked enlarged right ovary. Further imaging, diagnostic tests, and eventually diagnostic laparoscopy revealed that the ovarian enlargement was secondary to subacute appendicitis, rather than a primary adnexal process. We review the classic ultrasound and MRI imaging findings and pitfalls that relate to this diagnosis.     

Right lower quadrant pain: not always appendicitis but epiploic appendagitis of appendix

Epiploic appendagitis is a condition that mimics acute abdomen, causing inflammation of epiploic appendages. This paper aimed to present a case of "epiploic appendagitis of the appendix", which is a rare cause of right lower quadrant pain. A 45-year-old male patient with abdominal pain was referred to the radiology clinic for abdominal CT. The pain localized to the right lower quadrant and no signs of peritoneal irritation were present on physical examination. On images of abdominal CT the diameter of the appendix measured as 7 mm. The wall thickness was within normal limits and no mucosal enhancement noted. Appendiceal air was present in the lumen. An oval lesion of fat density with a hyperdense rim was seen adjacent to the anterior part of the appendix. It was causing striations and heterogeneous appearance in the surrounding mesenteric fat tissue with central areas of high attenuation. The findings noted down as “hyper-attenuating ring sign” and “central dot sign”. These pathognomonic CT findings were consistent with epiploic appendagitis and the case reported as epiploic appendagitis of the appendix. After conservative non-surgical medical treatment symptoms of patient revealed. To prevent unnecessary surgery, it is important to exclude conditions requiring emergency surgical intervention with imaging. The most effective technique recommended for imaging is CT with IV opaque. Increasing awareness and knowledge of radiologists regarding epiploic appendagitis of the appendix will rule out the possibility of potential misdiagnosis in imaging and will avoid the resultant unnecessary surgery.     

Imaging manifestations of abdominal fat necrosis and its mimics

Intraabdominal fat is a metabolically active tissue that may undergo necrosis through a number of mechanisms. Fat necrosis is a common finding at abdominal cross-sectional imaging, and it may cause abdominal pain, mimic findings of acute abdomen, or be asymptomatic and accompany other pathophysiologic processes. Common processes that are present in fat necrosis include torsion of an epiploic appendage, infarction of the greater omentum, and fat necrosis related to trauma or pancreatitis. In addition, other pathologic processes that involve fat may be visualized at computed tomography, including focal lipohypertrophy, pathologic fat paucity (lipodystrophies), and malignancies such as liposarcoma, which may mimic benign causes of fat stranding. Because fat necrosis and malignant processes such as liposarcoma and peritoneal carcinomatosis may mimic one another, knowledge of a patient's clinical history and prior imaging studies is essential for accurate diagnosis.     

Primary epiploic appendagitis: a report of two cases

Primary epiploic appendagitis (PEA) is a rare benign self-limiting inflammatory process of the colonic epiploic appendices. Patients present with acute abdominal pain, often misdiagnosed clinically as acute appendicitis or diverticulitis. Computed tomography (CT) scan findings of this condition are characteristic and can confidently suggest the diagnosis avoiding unnecessary barium enemas and colonoscopy, biopsy, or surgery.     

MRI Findings of Pericardial Fat Necrosis: Case Report

Pericardial fat necrosis is an infrequent cause of acute chest pain and this can mimic acute myocardial infarction and acute pericarditis. We describe here a patient with the magnetic resonance imaging (MRI) findings of pericardial fat necrosis and this was correlated with the computed tomography (CT) findings. The MRI findings may be helpful for distinguishing pericardial fat necrosis from other causes of acute chest pain and from the fat-containing tumors in the cardiophrenic space of the anterior mediastinum.     

Imaging features of lymphangioleiomyomatosis: diagnostic pitfalls

OBJECTIVE: The objective of this article is to illustrate CT findings that may be misinterpreted and lead to unnecessary biopsy or surgical procedures in patients with lymphangioleiomyomatosis. CONCLUSION: Sequelae of pleurodesis, acutely hemorrhagic renal angiomyolipomas, and lymphatic involvement with lymphangioleiomyomatosis including enlarged lymph nodes and lymphangioleiomyomas are common benign conditions seen in patients with lymphangioleiomyomatosis that may be misdiagnosed on CT for malignancy and may prompt unnecessary biopsy and surgery. Ruptured abdominal pelvic lymphangioleiomyomas may be mistaken for appendicitis and other acute abdominal pelvic events.     

Extrahepatic, nonneoplastic, fat-containing lesions of the abdominopelvic cavity: spectrum of lesions, significance, and typical appearance on multidetector computed tomography

Fat may be noted in a diffuse or focal manner in a variety of nonneoplastic abdominopelvic conditions. The specific signature of macroscopic fat on computed tomography along with the usually characteristic findings of these entities makes the diagnosis of most of these conditions relatively straightforward. In the intestinal tract, the "fat halo sign" usually arises in the context of subacute to chronic bowel wall inflammation. Excess fat in the renal sinus may occur with renal sinus lipomatosis or "replacement lipomatosis of the kidney." Some cases of "pancreatic lipomatosis" may culminate in steatopancreatitis and ultimately neoplastic transformations. "Fibrofatty mesenteric proliferation" is a characteristic feature of Crohn disease. In the setting of the acute abdomen, accurate diagnosis of fat-containing lesions (epiploic appendagitis or omental infarction) from other causes of the acute abdomen is critical. Mesenteric panniculitis is 1 of the causes of the "misty mesentery." Juxtacaval fat deposition is a benign process that has the potential to be confused with more serious conditions. More diffuse fat deposition (abdominal or pelvic lipomatosis) has the potential to become symptomatic by causing mass effect upon the adjacent structures. Fat can also be seen in a variety of postoperative/iatrogenic conditions or abdominal wall/diaphragmatic hernias.     

Functional cine MR imaging for the detection and mapping of intraabdominal adhesions: method and surgical correlation

The purpose of this study was to evaluate the presence and localization of intraabdominal adhesions using functional cine magnetic resonance imaging (MRI) and to correlate the MR findings with intraoperative results. In a retrospective study, patients who had undergone previous abdominal surgery with suspected intraabdominal adhesions were examined. A true fast imaging with steady state precession sequence in transverse/sagittal orientation was used for a section-by-section dynamic depiction of visceral slide on a 1.5-Tesla system. After MRI, all patients underwent anew surgery. A nine-segment abdominal map was used to document the location and type of the adhesions. The intraoperative results were taken as standard of reference. Ninety patients were enrolled. During surgery 71 adhesions were detected, MRI depicted 68 intraabdominal adhesions. The most common type of adhesion in MRI was found between the anterior abdominal wall and small bowel loops (n = 22, 32.5%) and between small bowel loops and pelvic organs (n = 14, 20.6%). Comparing MRI with the intraoperative findings, sensitivity varied between 31 and 75% with a varying specificity between 65 and 92% in the different segments leading to an overall MRI accuracy of 89%. Functional cine MRI proved to be a useful examination technique for the identification of intraabdominal adhesions in patients with acute or chronic pain and corresponding clinical findings providing accurate results. However, no differentiation for symptomatic versus asymptomatic adhesions is possible. Sonja Buhmann and Reinhold Lang contributed equally to this work.     

Perisplenic pseudolesion: a case report and literature review

Distinguishing a normal variant from true pathology is a frequent task of the imager. In the assessment of the trauma patient, rapid determination of the presence or absence of intraabdominal injury is of paramount importance. We present the sonographic findings of an anatomic variant detected in a patient following blunt abdominal trauma. Trauma sonogram revealed an elongated left lobe of the liver mimicking a subcapsular splenic hematoma. This case illustrates the importance of recognizing this potential pitfall in the setting of abdominal trauma. An equivocal trauma sonogram can lead to critical delays in treatment of associated injuries and unnecessary additional imaging or even surgery.     

Ecografía intestinal y abdomen agudo: más allá de la apendicitis aguda

Acute abdomen is a common reason for consultation in the emergency department. A broad spectrum of entities, including diverse diseases of the gastrointestinal tract, can cause acute abdomen. Although computed tomography is the technique most widely used to evaluate acute abdomen in the emergency department, abdominal ultrasound is often performed first and allows bowel disease to be suspected. This article describes the ultrasound features of diverse bowel diseases that can cause acute abdomen, such as acute diverticulitis, bowel obstruction, gastrointestinal perforation, bowel ischemia, intraabdominal fat necrosis, and miscellaneous processes such as endometriosis, foreign bodies, or vasculitis. Radiologists must be familiar with the different features of abnormal bowel that can be detected incidentally in patients without clinical suspicion of bowel disease. This article focuses on ultrasonographic signs of bowel disease; other articles in this series cover the ultrasonographic signs of acute appendicitis, inflammatory bowel disease, and infectious diseases.     

Segmental infarction of the omentum secondary to torsion: ultrasound and computed tomography diagnosis

Segmental infarction of the omentum is a rare clinical entity that is seldom considered in the differential diagnosis for acute abdominal pain, especially as the clinical findings are so non-specific. Consequently, the diagnosis is usually made intraoperatively. The two cases presented here demonstrate the characteristic appearance of omental infarction on ultrasound and CT, which enables preoperative diagnosis. Preoperative radiological diagnosis may prevent unnecessary surgery.     

Eosinophilic gastroenteritis

Eosinophilic gastroenteritis is an uncommon cause of abdominal pain which may mimic other causes of acute abdominal pain and result in unnecessary laparotomy. In many cases clues to the diagnosis are available prior to surgery; however a high index of suspicion must be maintained if the condition is to be identified at presentation. Two cases are described followed by a review of the disease entity.     

Omental infarction as a delayed complication of abdominal surgery.

Omental infarction, an uncommon cause of acute abdominal pain, is the result of compromised perfusion to the greater omentum. Although its etiology remains uncertain, predisposing factors include obesity [Surg. Today 30 (2000) 451], strenuous activity [N. Z. Med. J. 111 (1998) 211], trauma, and idiopathic omental torsion. Often confused with acute appendicitis or cholecystitis on clinical grounds [Surg. Today 30 (2000) 451], its diagnosis has traditionally been one of exclusion, based on intraoperative and pathologic findings. This diagnosis can be made radiologically based on the characteristic findings of an inflammatory mass containing fat and fluid. We describe a case of right lower quadrant omental infarction temporally related to bowel surgery.     

CT and MR imaging findings of bowel ischemia from various primary causes.

Ischemic bowel disease represents a broad spectrum of diseases with various clinical and radiologic manifestations, which range from localized transient ischemia to catastrophic necrosis of the gastrointestinal tract. The primary causes of insufficient blood flow to the intestine are diverse and include thromboembolism, nonocclusive causes, bowel obstruction, neoplasms, vasculitis, abdominal inflammatory conditions, trauma, chemotherapy, radiation, and corrosive injury. Computed tomography (CT) or magnetic resonance (MR) imaging can demonstrate the ischemic bowel segment and may be helpful in determining the primary cause. The CT and MR imaging findings include bowel wall thickening with or without the target sign, intramural pneumatosis, mesenteric or portal venous gas, and mesenteric arterial or venous thromboembolism. Other CT findings include engorgement of mesenteric veins and mesenteric edema, lack of bowel wall enhancement, increased enhancement of the thickened bowel wall, bowel obstruction, and infarction of other abdominal organs. However, regardless of the primary cause, the imaging findings of bowel ischemia are similar. Furthermore, the bowel changes simulate inflammatory or neoplastic conditions. Understanding the pathogenesis of various conditions leading to mesenteric ischemia helps the radiologist recognize ischemic bowel disease and avoid delayed diagnosis, unnecessary surgery, or less than optimal management.     

MDCT of acute cecal conditions

The cecum comprises a relatively short segment of the gastrointestinal tract, but it can be affected by numerous acute conditions. Acute conditions may arise from processes primary to the cecum, such as volvulus, bascule, neoplasm, and trauma. Alternatively, acute conditions can be due to secondary to systemic or nearby pathology, such as infection, inflammatory processes, ischemia, and infarction. While it is common to suspect appendicitis as the etiology of acute right lower quadrant abdominal pain, the cecum should also be considered as a potential cause of pain, especially in the setting of an abnormal or absent appendix. Multi-detector computed tomography (MDCT) has evolved to become the best imaging modality to evaluate patients presenting with right lower quadrant abdominal pain or suspected acute cecal pathology. Strengths of MDCT include rapid acquisition of images, high spatial resolution, and ability to create multi-planar reconstructed images. In this pictorial review, we illustrate and describe key MDCT findings for various acute cecal conditions with which the emergency radiologist should be familiar.     

CT features of primary epiploic appendagitis

OBJECTIVE: The aim of this study is to describe the computed tomography (CT) findings of primary epiploic appendagitis (PEA). METHODS: We reviewed the clinical records and CT images of 14 consecutive patients in Singapore who presented with acute abdominal pain from July 2000 to April 2004 and had radiological signs of PEA. RESULTS: Hyperattenuated ring with adjacent fat stranding was present in all the patients. The central high attenuation dot was seen in 42.9% (6/14) of the patients. We observed a lobulated fatty mass in 21.4% (3/14) of our patients. All patients recovered during clinical follow-up. CONCLUSIONS: We believe the lobulated appearance of PEA is due to two or more, contiguous infarcted epiploic appendages lying in close proximity. This appearance further aids in the diagnosis of PEA and helps differentiates the condition from omental infarction. Recognizing the CT signs of PEA should allow a confident diagnosis and avoid unnecessary surgery.     

Lap-belt injuries of the lumbar spine in children: a pitfall in CT diagnosis

A retrospective review of 365 consecutive CT studies in children assessed for intraabdominal trauma yielded five children in whom lap-belt-associated injuries of the lumbar spine were missed on CT. Facet subluxation and anterior dislocation of the third lumbar vertebra were present in four patients and multiple compression fractures were present in one. Clinical presentations included acute abdominal symptoms; two had acute back pain, and three experienced delayed onset of back pain. Although the injuries to the spine were visible retrospectively on anteroposterior radiographs, the findings were subtle and their extent was best appreciated on lateral lumbar spine views. Five of 365 patients with blunt abdominal trauma were identified as having sustained midlumbar spinal injury that was clearly visible only on a lateral radiograph of the spine.     

Segmental testicular infarction: report of seven new cases and literature review

Segmental testicular infarction is a relatively rare acute or subacute condition which is infrequently thought of in the differential diagnosis for testicular pain. However, missing or misdiagnosing this entity on clinical evaluation and/or imaging has significant implications for patients as they may undergo unnecessary surgery for suspected testicular torsion or tumor. Knowledge and recognition of the features of segmental testicular infarction on ultrasound and MRI will aid in the diagnosis of this disease early in the patient's course. The common imaging features of segmental testicular infarction and the clinical literature are reviewed, with an emphasis on ultrasound, utilizing seven recent cases from three institutions.