Wai-Kit Lee

Infected (Mycotic) Aneurysms : Spectrum of Imaging Appearances and Management

Infected aneurysms are uncommon. The aorta, peripheral arteries, cerebral arteries, and visceral arteries are involved in descending order of frequency. Staphylococcus and Streptococcus species are the most common causative pathogens. Early clinical diagnosis of infected aneurysms is challenging owing to their protean manifestations. Clinically apparent infected aneurysms are often at an advanced stage of development or are associated with complications, such as rupture. Nontreatment or delayed treatment of infected aneurysms often has a poor outcome, with high morbidity and mortality from fulminant sepsis or hemorrhage. Current state-of-the-art imaging modalities, such as multidetector computed tomography and magnetic resonance imaging, have replaced conventional angiography as minimally invasive techniques for detection of infected aneurysms in clinically suspected cases, as well as characterization of infected aneurysms and vascular mapping for treatment planning in confirmed cases. Doppler ultrasonography allows noninvasive assessment for infected aneurysms in the peripheral arteries. Imaging features of infected aneurysms include a lobulated vascular mass, an indistinct irregular arterial wall, perianeurysmal edema, and a perianeurysmal soft-tissue mass. Perianeurysmal gas, aneurysmal thrombosis, aneurysmal wall calcification, and disrupted arterial calcification at the site of the infected aneurysm are uncommon findings. Imaging-guided endovascular stent-graft repair and embolotherapy can be performed in select cases instead of open surgery. Familiarity with the imaging appearances of infected aneurysms should alert the radiologist to the diagnosis and permit timely treatment, which may include endovascular techniques.

CT appearances of abdominal tuberculosis

The purpose of this article is to review and illustrate the spectrum of computed tomography (CT) appearances of abdominal tuberculosis. Tuberculosis can affect any organ or tissue in the abdomen, and can be mistaken for other inflammatory or neoplastic conditions. The most common sites of tuberculosis in the abdomen include lymph nodes, genitourinary tract, peritoneal cavity and gastrointestinal tract. The liver, spleen, biliary tract, pancreas and adrenals are rarely affected, but are more likely in HIV-seropositive patients and in miliary tuberculosis. This article should alert the radiologist to consider abdominal tuberculosis in the correct clinical setting to ensure timely diagnosis and enable appropriate treatment.

Abdominal Manifestations of Extranodal Lymphoma: Spectrum of Imaging Findings

OBJECTIVE The purpose of this article is to illustrate the spectrum of appearances of extranodal lymphoma in the abdomen using cross-sectional imaging techniques. CONCLUSION Extranodal lymphoma in the abdomen can mimic other neoplastic or inflammatory conditions. Although a definitive diagnosis is possible only with biopsy, it is important to consider extranodal lymphoma in the presence of certain imaging appearances in the appropriate clinical setting for the correct diagnosis, accurate staging, and optimal management.

Imaging Assessment of Congenital and Acquired Abnormalities of the Portal Venous System

Abnormalities of the portal venous system are a heterogeneous group of conditions that can cause substantial morbidity and mortality and may lead to complications during surgery or percutaneous interventions involving the portal venous system. High-resolution computed tomography, ultrasonography, and magnetic resonance imaging permit a comprehensive, noninvasive evaluation of the portal venous system, enabling the detection of both structural and functional abnormalities. However, an understanding of the embryologic development of the normal portal venous anatomy and anatomic variants is essential to accurately interpret the imaging findings. Knowledge of the characteristic appearances of abnormalities of the portal venous system allows a more confident diagnosis, permitting timely treatment and more informed guidance of surgical procedures and percutaneous interventions, which may lead to an improved outcome.

Extracolonic findings at CT colonography: A review of 258 consecutive cases

Introduction: Computed tomographic colonography (CTC) is a non‐invasive method of examining the colon and is used for colorectal polyp and mass diagnosis. As the entire abdomen is examined, incidental extracolonic pathologies can be diagnosed. The types of extracolonic findings (ECFs) and their frequency have not been explored in an Australian setting.

Imaging findings of unusual anorectal and perirectal pathology: a multi-modality approach.

The objective of this review is to discuss the less common causes of rectal and perirectal disease with an emphasis on their differentiating radiological features and the importance of a multimodality imaging approach. Radiologists should be aware of the ultrasound, computed tomography, and magnetic resonance imaging appearances of the wide variety of uncommon lesions arising from the rectal and perirectal regions that may simulate adenocarcinoma in order to render an accurate diagnosis and facilitate appropriate management.

Renal Cell Carcinoma Metastasis to the Breast: Mammographic, Sonographic, CT, and Pathologic Correlation

A 71-year-old woman presented with a 7-month history of a rapidly enlarging right breast lump and discomfort in the right upper quadrant of the abdomen. Mammography showed a 4-cm, circumscribed, solitary, round mass without internal microcalcification at 8-o’clock 8-cm from the right nipple (Fig. 1a). Sonography showed a hypoechoic lobulated mass (Fig. 1b) with prominent peripheral vascularity and penetrating vessels at color Doppler (Fig. 1c). A staging contrast-enhanced chest computed tomography (CT) showed an enhancing, homogenous right breast mass (Fig. 1d) and an abdominal CT showed a 16-cm right renal tumor. Sonography-guided core biopsy of the right breast mass was performed. The histology showed a tumor that is composed of nests and cords of cells with clear cytoplasm separated by a prominent sinusoidal vascular network (Fig. 1e), which shows strong positive membrane staining for CD10 that is characteristic of renal cell carcinoma of clear cell type (Fig. 1f). She elected interleukin-2 immunotherapy and presented five months later with a solitary cerebral metastasis, which was successfully resected. She remains alive to date. Renal cell carcinoma metastases to the breast are rare. A total of 0.2–1.3% of all breast malignancies are due to extramammary metastases to the breast. The mammographic and sonographic appearances of extramammary metastases to the breast may mimic a benign breast mass due to the absence of desmoplastic reaction. The sonographic pattern of prominent peripheral and penetrating vessels in the tumor is highly suggestive of a malignancy. Metastases to the breast may be identified on chest CT performed for tumor staging or surveillance.

Metastasis to the breast from an adenocarcinoma of the colon.

Metastases to the breast from extramammary malignancies are rare. We report a case of metastasis to the breast from a colonic adenocarcinoma in a 50‐year‐old man who was 6 years status after a right hemicolectomy for T3N1M1 adenocarcinoma of the ascending colon. Sonographic evaluation of the right breast lump showed a hypoechoic mass with slightly irregular margins, but there was no internal vascularity. Chest CT also documented a poorly enhancing suspicious mass in the right breast. The diagnosis of adenocarcinoma metastasis to the breast was achieved with sonographically guided core biopsy.

Percutaneous and endovascular embolization of ruptured hepatic artery aneurysm.

A 72-year-old woman presented with an intraperitoneal hemorrhage from a ruptured intrahepatic artery aneurysm, with an associated pseudoaneurysm developing a high-flow arteriovenous fistula. Persistent coagulopathy and a median arcuate ligament stenosis of the celiac axis further complicated endovascular management. Aneurysm thrombosis required percutaneous embolization with coils, a removable core guidewire and polyvinyl alcohol particles.

Diffuse mesenteric extramedullary hematopoiesis with ascites: sonography, CT, and MRI findings.

1All authors: Department of Medical Imaging, St. Vincents Hospital, University of Melbourne, 41 Victoria Parade, Fitzroy, Victoria 3065, Australia. Address correspondence to W.-K. Lee. xtramedullary hematopoiesis is ectopic hematopoiesis that occurs as a compensatory response to insufficient bone marrow hematopoiesis. Clinically apparent extramedullary hematopoiesis in the gastrointestinal tract is rare [1]. It may cause bowel obstruction, simulate a carcinoma, or present with ascites [2, 3]. There are several case reports that diagnosed mesenteric infiltration by extramedullary hematopoiesis at surgery or biopsy [3, 4], but there is a paucity in the literature of the imaging findings of diffuse mesenteric extramedullary hematopoiesis. We present the sonographic, CT, and MRI findings in a histologically confirmed case of diffuse peritoneal extramedullary hematopoiesis with ascites.