Giovanna Casola

Fatty Liver: Imaging Patterns and Pitfalls

Fat accumulation is one of the most common abnormalities of the liver depicted on cross-sectional images. Common patterns include diffuse fat accumulation, diffuse fat accumulation with focal sparing, and focal fat accumulation in an otherwise normal liver. Unusual patterns that may cause diagnostic confusion by mimicking neoplastic, inflammatory, or vascular conditions include multinodular and perivascular accumulation. All of these patterns involve the heterogeneous or nonuniform distribution of fat. To help prevent diagnostic errors and guide appropriate work-up and management, radiologists should be aware of the different patterns of fat accumulation in the liver, especially as they are depicted at ultrasonography, computed tomography, and magnetic resonance imaging. In addition, knowledge of the risk factors and the pathophysiologic, histologic, and epidemiologic features of fat accumulation may be useful for avoiding diagnostic pitfalls and planning an appropriate work-up in difficult cases.

MR imaging of liver fibrosis: current state of the art.

Chronic liver disease is a major public health problem worldwide. Liver fibrosis, a common feature of almost all causes of chronic liver disease, involves the accumulation of collagen, proteoglycans, and other macromolecules within the extracellular matrix. Fibrosis tends to progress, leading to hepatic dysfunction, portal hypertension, and ultimately cirrhosis. Liver biopsy, the standard of reference for diagnosing liver fibrosis, is invasive, costly, and subject to complications and sampling variability. These limitations make it unsuitable for diagnosis and longitudinal monitoring in the general population. Thus, development of a noninvasive, accurate, and reproducible test for diagnosis and monitoring of liver fibrosis would be of great value. Conventional cross-sectional imaging techniques have limited capability to demonstrate liver fibrosis. In clinical practice, imaging studies are usually reserved for evaluation of the presence of portal hypertension or hepatocellular carcinoma in cases that have progressed to cirrhosis. In response to the rising prevalence of chronic liver diseases in Western nations, a number of imaging-based methods including ultrasonography-based transient elastography, computed tomography-based texture analysis, and diverse magnetic resonance (MR) imaging-based techniques have been proposed for noninvasive diagnosis and grading of hepatic fibrosis across its entire spectrum of severity. State-of-the-art MR imaging-based techniques in current practice and in development for noninvasive assessment of liver fibrosis include conventional contrast material-enhanced MR imaging, double contrast-enhanced MR imaging, MR elastography, diffusion-weighted imaging, and MR perfusion imaging.

Percutaneous Abscess Drainage: Update

During the approximately 20 years that percutaneous abscess drainage (PAD) has been an extant procedure and as the millennium begins, PAD has become, by consensus, the treatment of choice for abscesses. Indications for PAD continue to expand, and currently almost all abscesses are considered amenable. On occasion, PAD is an adjunctive procedure that provides a beneficial temporizing effect for the surgeon who eventually must operate for a coexisting problem such as a bowel leak. Simple unilocular abscesses are cured almost uniformly by PAD; more complicated abscesses, such as those with enteric fistulas (e.g., diverticular abscess) or pancreatic abscesses, have cure rates ranging from 65% to 90%. Various catheters and insertion techniques have proven effective. Ultrasonography, computed tomography, and fluoroscopy are the staple modalities that guide PAD. PAD is the prototype interventional radiology procedure, providing detection of the abscess by imaging, needling for diagnosis, and catheterization for therapy.

A prospective evaluation of abdominal ultrasound in blunt trauma: is it useful?

OBJECTIVE The purpose of this study is to evaluate the utility and feasibility of abdominal ultrasound (US) in blunt trauma patients. DESIGN This prospective study examined the operational issues and the diagnostic accuracy of US in selected blunt trauma patients triaged to a Level 1 trauma center. MATERIALS AND METHODS All patients were evaluated by an attending trauma surgeon and our usual criteria for objective evaluation of the abdomen were applied. US was performed by US technicians and interpreted by the trauma surgeon. We prospectively evaluated the availability (time to arrival), the ease with which the US could be integrated into the resuscitation (minutes to start after arrival), and the time required to perform the study. The US results were compared to diagnostic peritoneal lavage and computed tomography findings, clinical course, operative findings, and to repeat US examinations to determine sensitivity, specificity, and usefulness. MEASUREMENTS AND MAIN RESULTS A total of 800 US studies were performed over 15 months. In four cases (0.5%), the US was incomplete for technical reasons. The results in the remaining 796 studies were as follows: [table: see text] The average time to arrival of the US was 17.3 minutes (range 0-120) and the average minutes to start after arrival was 7.0 (range 1-49). The average time required to perform the study was 10.6 minutes (range 2-26). CONCLUSIONS This study demonstrates that US can be obtained rapidly, integrated into the resuscitation, and completed quickly. US provides a highly accurate, noninvasive method to evaluate the abdomen in the blunt trauma patient, and has supplanted the previously used methods at this institution.

Laparoscopic injuries to the bile duct. A cause for concern.

The authors report six patients who had injuries to their common hepatic bile duct at laparoscopie cholecystectomy over a 16-month period. Five of the six complications could be attributed to laser injuries during dissection in the region of Calots triangle. The authors discuss the possible mechanism of these injuries, their perioperative management, and the methods of surgical reconstruction. The follow-up period ranges from 3 months to 21 months. Liver function parameters and isotope biliary excretion scans are back to normal in all six patients. The potential hazards of laparoscopie surgery demand that extraordinary care be used not only during the actual surgical procedure, but also in the preoperative decision concerning the dissection method to be employed.

Pulmonary Embolism at CT Angiography: Implications for Appropriateness, Cost, and Radiation Exposure in 2003 Patients

PURPOSE To determine whether thromboembolic risk factor assessment could accurately indicate the pretest probability for pulmonary embolism (PE), and if so, computed tomographic (CT) angiography might be targeted more appropriately than in current usage, resulting in decreased costs and radiation exposure. MATERIALS AND METHODS Institutional review board approval was obtained. Electronic medical records of 2003 patients who underwent CT angiography for possible PE during 1(1/2) years (July 2004 to February 2006) were reviewed retrospectively for thromboembolic risk factors. Risk factors that were assessed included immobilization, malignancy, hypercoagulable state, excess estrogen state, a history of venous thromboembolism, age, and sex. Logistic regressions were conducted to test the significance of each risk factor. RESULTS Overall, CT angiograms were negative for PE in 1806 (90.16%) of 2003 patients. CT angiograms were positive for PE in 197 (9.84%) of 2003 patients; 6.36% were Emergency Department patients, and 13.46% were inpatients. Of the 197 patients with CT angiograms positive for PE, 192 (97.46%) had one or more risk factors, of which age of 65 years or older (69.04%) was the most common. Of the 1806 patients with CT angiograms negative for PE, 520 (28.79%) had no risk factors. The sensitivity and negative predictive value of risk factor assessment in all patients were 97.46% and 99.05%, respectively. All risk factors, except sex, were significant in the multivariate logistic regression (P < .031). CONCLUSION In the setting of no risk factors, it is extraordinarily unlikely (0.95% chance) to have a CT angiogram positive for PE. This selectivity and triage step should help reduce current costs and radiation exposure to patients.

Significance of minimal or no intraperitoneal fluid visible on CT scan associated with blunt liver and splenic injuries: A multicenter analysis

BACKGROUND The use of ultrasound (U/S) for the evaluation of patients with blunt abdominal trauma is gaining increasing acceptance. Patients who would have undergone computed tomographic (CT) scan may now be evaluated solely with U/S. Solid organ injuries with minimal or no free fluid may be missed by surgeon sonographers. OBJECTIVE The purpose of this study was to describe the incidence and clinical importance of liver and splenic injuries with minimal or no free intraperitoneal fluid visible on CT scan. We hypothesized that these solid organ injuries occur infrequently and are of minor clinical significance. METHODS Patient records and CT scans were reviewed for the presence of and outcome associated with blunt liver and splenic injuries with minimal (<250 mL) or no free fluid detected by an attending radiologist. Data were collected from six major trauma centers during a 4-year period before the introduction of U/S and included demographics, grade of injury (American Association for the Surgery of Trauma scale), need for operative intervention, and outcome. RESULTS A total of 938 patients with liver and splenic injuries were identified. In this group, 11% of liver injuries and 12% of splenic injuries had no free fluid visible on CT scan and could be missed by diagnostic peritoneal lavage or U/S. Of the 938 patients, 267 (28%) met the inclusion criteria; 161 had injury to the spleen and 125 had injury to the liver. In the 267 patients studied, 97% of the injuries were managed nonoperatively. However, 8 patients (3%) required operative intervention for bleeding. Compared with the liver, the spleen was significantly more likely to bleed (p = 0.01), but the grade of splenic injury was not related to the risk for hemorrhage (p = 0.051). CONCLUSION Data from this study suggest that injuries to the liver or spleen with minimal or no intraperitoneal fluid visible on CT scan occur more frequently than predicted but usually are of minimal clinical significance. However, patients with splenic injuries may be missed by abdominal U/S. We found a 5% associated risk of bleeding. Therefore, abdominal U/S should not be used as the sole diagnostic modality in all stable patients at risk for blunt abdominal injury.

Percutaneous drainage of infected and noninfected thoracic fluid collections

Radiologically guided aspiration and drainage of thoracic fluid collections is an improvement on standard “blind” techniques for chest-tube insertion. Specific indications for radiologic drainage are broadening, and instead of failed surgical cases only, patients now are commonly referred for drainage. Most of these procedures are effective and the complication rate vis-à-vis alternatives is acceptable. Soft 12-F catheters suffice in most cases and are relatively comfortable compared to large-bore tubes.

Importance of evaluating organ parenchyma during screening abdominal ultrasonography after blunt trauma.

To determine the benefit of screening ultrasonography for parenchymal abnormalities as well as free fluid during screening abdominal ultrasonography in patients with blunt trauma.

Screening sonography in pregnant patients with blunt abdominal trauma

The purpose of this study was to evaluate the accuracy of screening sonography for the detection of clinically significant abdominal injury in pregnant patients with blunt trauma.