Intraabdominal Mycobacterium tuberculosis vs Mycobacterium avium-intracellulare infections in patients with AIDS: distinction based on CT findings

Abdominal CT scans of 71 patients with AIDS who had proved disseminated infection due to Mycobacterium tuberculosis (27 patients) or Mycobacterium avium-intracellulare (44 patients) were reviewed retrospectively to identify radiologic features that can be used to distinguish the two infections. CT findings in patients with disseminated M. tuberculosis included focal lesions in the liver (11%), spleen (30%), kidneys (19%), pancreas (7%), and gastrointestinal tract (15%) and lymph nodes with central or diffuse low attenuation (93%). CT findings in patients with disseminated M. avium-intracellulare included marked hepatomegaly (20%); marked splenomegaly (14%); focal lesions in the liver (9%), spleen (7%), and kidneys (2%); diffuse jejunal wall thickening (18%); lymph nodes with central low attenuation (14%); and enlarged lymph nodes exclusively of homogeneous soft-tissue density (55%). The presence of focal visceral lesions and low-attenuation lymph nodes suggests disseminated M. tuberculosis, whereas marked hepatic and splenic enlargement, diffuse jejunal wall thickening, and enlarged soft-tissue-density lymph nodes suggest disseminated M. avium-intracellulare. Recognition of these CT features can lead to a tentative diagnosis so that appropriate therapy can be instituted before the results of mycobacterial cultures become available.     

Abdominal sonographic findings in patients with AIDS

The ultrasound findings of 58 patients with AIDS and ARC were analysed retrospectively. In 55% an enlarged liver, in 62% an enlarged spleen, partially with focal lesions, and in 21% enlarged abdominal lymph nodes were diagnosed. The typical focal segmental glomerulosclerosis of the kidney was observed in one case, and cholangitis in 2 patients. Abdominal ultrasound is the first diagnostic procedure to be performed in patients with AIDS and ARC when abdominal pathology is suspected. With US-guided thin needle puncture of the lesions, a histological verification of the pathologic findings is possible.     

Abdominal aspergillosis: CT findings

Objective

In order to retrospectively evaluate the CT findings of abdominal aspergillosis in immunocompromised patients.

Materials and methods

CT scans were reviewed with regard to the sites, number, morphologic appearance, attenuation, and the contrast enhancement patterns of the lesions in six patients (5 women, 1 man; mean age, 43.4 years; range, 23-59 years) with pathologically proved abdominal aspergillosis by two gastrointestinal radiologists in consensus. Medical records were also reviewed to determine each patient's clinical status and outcome.

Results

All patients were immunocompromised state: 4 patients received immunosuppressive therapy for solid organ transplantation and 2 patients received chemotherapy for acute myeloid leukemia. Aspergillosis involved blood vessels (n = 3), liver (n = 2), spleen (n = 2), gastrointestinal tract (n = 2), native kidney (n = 1), transplanted kidney (n = 1), peritoneum (n = 1), and retroperitoneum (n = 1). CT demonstrated solid organ or bowel infarction or perforation secondary to vascular thrombosis or pseudoaneurysm, multiple low-attenuating lesions of solid organs presenting as abscesses, concentric bowel wall thickening mimicking typhlitis, or diffuse or nodular infiltration of the peritoneum and retroperitoneum.

Conclusion

Familiarity with findings commonly presenting as angioinvasive features or abscesses on CT, may facilitate the diagnosis of rare and fatal abdominal aspergillosis.     

Abdominal tuberculosis: CT findings

The computed tomographic (CT) characteristics of intraabdominal tuberculosis are not specific. A recent article from South Africa proposed a set of criteria that included high density ascites and mesenteric involvement, consisting of thickening and adenopathy, as possible criteria for the diagnosis of tuberculous peritonitis by CT. Review of three additional cases of abdominal tuberculosis showing these findings supports the criteria defined in the earlier study. Although not definitive, these findings in the appropriate clinical setting should suggest the possibility of tuberculosis.     

Abdominal CT findings in nontraumatic colorectal perforation

Colorectal perforation is an emergent medical condition in which the diagnosis and the etiology are often established on CT, the common imaging modality used for evaluating the acute abdomen. The cardinal, direct CT features suggesting perforation are extraluminal air and enteric contrast, added by secondary signs of bowel pathology, such as focal bowel wall thickening and bowel wall defect. This pictorial review will illustrate the CT findings of colorectal perforation caused by various clinical entities.     

Abdominal CT findings in small bowel perforation

Small bowel perforation is an emergent medical condition for which the diagnosis is usually not made clinically but by CT, a common imaging modality used for the diagnosis of acute abdomen. Direct CT features that suggest perforation include extraluminal air and oral contrast, which are often associated with secondary CT signs of bowel pathology. This pictorial review illustrates the CT findings of small bowel perforation caused by various clinical entities.     

Abdominal lymphadenopathy: spectrum of CT findings

Many malignant processes cause abdominal lymphadenopathy, and computed tomography (CT) has become the primary modality for its detection. Diagnosis of lymphadenopathy is facilitated by optimal imaging techniques and a knowledge of the various nodal chains, their complex interconnections, and preferential pathways of spread. Optimal techniques include imaging after oral administration of adequate amounts of barium suspension and dynamic scanning after intravenous administration of contrast material with an infusion pump. Although such techniques help prevent misdiagnoses due to normal and anomalous vascular structures, other benign diseases can mimic the CT appearance of malignant lymphadenopathy. The authors emphasize a regional approach for the diagnosis of lymphadenopathy, according to the groupings of retrocrural, retroperitoneal, gastrohepatic ligament, porta hepatis, celiac and superior mesenteric artery, pancreaticoduodenal, perisplenic, mesenteric, and pelvic lymph nodes. Lymphadenopathy is defined as retrocrural nodes greater than 6 mm in short axis, upper abdominal nodes greater than 10 mm, and pelvic nodes greater than 15 mm.     

Imaging of Mycobacterium avium-intracellulare infection in AIDS patients on highly active antiretroviral therapy: reversal syndrome

OBJECTIVE: We recently encountered six patients with AIDS and an unusual complication of disseminated infection with Mycobacterium avium-intracellulare, which developed after the initiation of highly active antiretroviral therapy, including protease inhibitors and two new nucleoside analogues. Each patient had a febrile illness after the initiation of therapy and then developed mass lesions containing mycobacterial organisms in various organ systems, including bone, skin, and mesenteric and mediastinal nodes. All these patients suddenly experienced improvement in immunologic status as evidenced by decreasing viral loads and increasing CD4 cell counts. We chose to call this reaction "M. avium-intracellulare reversal syndrome." We describe the radiologic appearance of this unusual manifestation of infection with M. avium-intracellulare in patients with AIDS. CONCLUSION: New or enlarging lymphadenopathy or unusual musculoskeletal and cutaneous infections in patients with AIDS who are receiving highly active antiretroviral therapy may represent a response of the recovering immune system to a new or previously subclinical infection with M. avium-intracellulare.     

Abdominal CT findings after liver transplantation in 66 patients

CT scanning is used frequently to assess the condition of patients after liver transplantation. The CT records of 174 adult patients who underwent liver transplantation were studied retrospectively to determine the number and timing of CT studies as well as the frequency and significance of the findings. One-hundred seventy CT scans were obtained in 66 (38%) of the 174 patients, with a mean of 2.6 scans/patient. The interval between transplantation and scanning was 1 day to 24 months; in 59 (89%) of 66 patients, the first CT scan was obtained within 30 days. The acute indications for CT scanning were fever or leukocytosis in 54 (92%) of 59 patients and abnormal liver function tests in five (8%) of 59 patients. CT scans obtained more than 30 days after transplantation were repeat scans in all but seven patients. Indications in this latter group were the same as for the acute group, plus evaluation of hepatic neoplasia in three patients. CT findings included periportal low attenuation in 41 (62%) of 66 patients; ascites in 25 (38%); splenomegaly in 19 (29%); loculated intraperitoneal noninfected fluid collections in 13 (20%); intrahepatic, splenic, pancreatic, or perihepatic abscesses in seven (11%); hepatic infarction in six (9%); splenic infarction in three (4%); and hepatic calcification in two (3%). Other major abnormalities included inferior vena caval thrombosis (one patient), pseudoaneurysm of the hepatic artery with rupture (one patient), and recurrent hepatocellular carcinoma (one patient). CT scanning after liver transplantation is used predominantly in the acute setting to evaluate for liver infarction or intraabdominal abscess. In this setting, CT showed these abnormalities, in addition to tumor recurrence or vascular abnormalities, in 15 (23%) of 66 patients.     

Abdominal desmoids: CT findings in 25 patients.

Desmoids are histologically benign but locally aggressive fibrous tumors. Although overall they are rare lesions, they are a common manifestation of Gardner syndrome. We retrospectively reviewed clinical records and CT scans of 25 patients with abdominal desmoids. The number, location, and CT characteristics of the lesions were recorded for each patient. Tumors were solitary in 72% of patients and multiple in 28%. Fifty percent were located in the abdominal wall, 41% in the mesentery, and 9% in the retroperitoneum. More than two thirds of the lesions had well-defined borders, with the remainder displaying an infiltrative outer margin. The majority of tumors had attenuation values equal to (47%) or greater than (41%) the attenuation of muscle on contrast-enhanced CT scans. Complications attributable to the desmoid were commonly detectable on CT (hydronephrosis occurred in 36% and small-bowel obstruction in 20%). Our results detail the spectrum of CT findings and complications caused by abdominal desmoids.     

Abdominal cystic lymphangiomas: US and CT findings

We retrospectively analyzed six cases of abdominal cystic lymphangiomas (CL), who had undergone surgical resection. These cases had been evaluated by several modalities: ultrasonography (US), computed tomography (CT), angiography and fine needle aspiration. No age predilection was found. All patients were symptomatic. The most common presenting symptoms were abdominal pain (66%), palpable mass (66%), fever (50%) and vomiting (30%). US showed septations (85%) and unicameral mass (15%); in three cases (50%) echogenic material within the cyst was found, probably due to hemorrhage and infection. CT showed capsular enhancement in all cases. Capsular and septation thickness were slightly increased in cases of infection or bleeding. At CT the contents were usually of fluid attenuation (66%); in 33% the attenuation values were higher, probably because of internal bleeding and infection. US was superior to CT in the demonstration of septations and the internal nature of the cysts. The major role of imaging is to demonstrate the cystic nature of these abdominal masses, because they do not have specific signs or symptoms that could allow a clinical diagnosis.     

肺淋巴管平滑肌增生症的腹部CT表现

目的探讨肺淋巴管平滑肌增生症腹部病变的CT表现。方法回顾性分析7例经病理证实的肺淋巴管平滑肌增生症，7例均作腹部CT扫描，对其腹部CT表现进行研究分析。结果7例患者中6例有腹部阳性表现：肾血管平滑肌脂肪瘤2例，其中1例合并胸导管增大、胸腔积液；腹膜后淋巴结肿大2例，合并腹水、胸腔积液1例；肝脏血管平滑肌脂肪瘤1例；腹膜后淋巴管肌瘤合并子宫肌瘤1例。结论肺淋巴管平滑肌增生症可并发腹部多脏器病变，CT扫描对发现和诊断其腹部病变具有重要意义。