Air embolism: diagnosis and management.

Air embolism is an uncommon, but potentially life-threatening event for which prompt diagnosis and management can result in significantly improved patient outcomes. Most air emboli are iatrogenic. Arterial air emboli may occur as a complication from lung biopsy, arterial catheterization or cardiopulmonary bypass. Immediate management includes placing the patient on high-flow oxygen and in the right lateral decubitus position. Venous air emboli may occur during pressurized venous infusions, or catheter manipulation. Immediate management includes placement of the patient on high-flow oxygen and in the left lateral decubitus and/or Trendelenburg position. Hyperbaric oxygen therapy is the definitive treatment which may decrease the size of air emboli by facilitating gas reabsorption, while also improving tissue oxygenation and reducing ischemic reperfusion injury.

Magnetic resonance elastography is accurate in detecting advanced fibrosis in autoimmune hepatitis.

AIM: To assess the value of magnetic resonance elastography (MRE) in detecting advanced fibrosis/cirrhosis in autoimmune hepatitis (AIH). METHODS: In this retrospective study, 36 patients (19 treated and 17 untreated) with histologically confirmed AIH and liver biopsy performed within 3 mo of MRE were identified at a tertiary care referral center. Liver stiffness (LS) with MRE was calculated by a radiologist, and inflammation grade and fibrosis stage in liver biopsy was assessed by a pathologist in a blinded fashion. Two radiologists evaluated morphological features of cirrhosis on conventional magnetic resonance imaging (MRI). Accuracy of MRE was compared to laboratory markers and MRI for detection of advanced fibrosis/cirrhosis. RESULTS: Liver fibrosis stages of 0, 1, 2, 3 and 4 were present in 4, 6, 7, 6 and 13 patients respectively. There were no significant differences in distribution of fibrosis stage and inflammation grade between treated and untreated patient groups. LS with MRE demonstrated stronger correlation with liver fibrosis stage in comparison to laboratory markers for chronic liver disease (r = 0.88 vs -0.48-0.70). A trend of decreased mean LS in treated patients compared to untreated patients was observed (3.7 kPa vs 3.84 kPa) but was not statistically significant. MRE had an accuracy/sensitivity/specificity/positive predictive value/negative predictive value of 0.97/90%/100%/100%/90% and 0.98/92.3%/96%/92.3%/96% for detection of advanced fibrosis and cirrhosis, respectively. The performance of MRE was significantly better than laboratory tests for detection of advanced fibrosis (0.97 vs 0.53-0.80, P < 0.01), and cirrhosis (0.98 vs 0.58-0.80, P < 0.01) and better than conventional MRI for diagnosis of cirrhosis (0.98 vs 0.78, P = 0.002). CONCLUSION: MRE is a promising modality for detection of advanced fibrosis and cirrhosis in patients with AIH with superior diagnostic accuracy compared to laboratory assessment and MRI.

Imaging of autoimmune hepatitis and overlap syndromes.

Autoimmune hepatitis (AIH) is an uncommon, chronic inflammatory, and relapsing liver disease of unknown origin that may lead to liver cirrhosis, hepatocellular carcinoma, liver transplantation, or death. AIH occurs in all age groups and races but can frequently manifest as acute fulminant hepatitis. Clinical presentation of AIH can have features similar to primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC), and these diseases may coexist leading to overlap syndromes. Although histological diagnosis is necessary, imaging features often can demonstrate characteristics that may be helpful to distinguish these diseases. Imaging features of AIH are those of chronic liver disease, and imaging plays important role in detection of complications and ruling out other possible causes of chronic liver disease. Emerging techniques such as elastography provide non-invasive options for diagnosis of significant fibrosis and cirrhosis during clinical follow-up as well as assessment of response to treatment. In this study, we will describe imaging findings in AIH and overlap syndromes.

Multimodality imaging of foreign bodies in and around the heart.

Foreign objects are occasionally seen on computed tomography and could pose a diagnostic challenge to the radiologist and clinicians. It is important to recognize, characterize and localize these objects and determine their clinical significance. Most foreign objects in and around the heart are the result of direct penetrating injury or represent venous embolization to the heart. Foreign objects may cause symptoms and require prompt medical attention or maybe asymptomatic. Clinicians should be familiar with foreign objects that are encountered and understand treatment options. This paper looks at some of foreign objects that can be found and correlates with pathology where possible.

The Yield of Pre-operative Breast MRI in Patients According to Breast Tissue Density.

OBJECTIVE: To determine the yield of pre-operative breast MRI according to breast tissue density. METHODS: We performed a retrospective review of 665 consecutive patients who underwent breast MRI in 2012 for pre-operative staging of biopsy-proven breast cancer, 582 of whom had digital mammograms available within 6 months of the MRI were evaluated for breast tissue density and additional lesions seen on breast MRI not identified on mammography. Lesions that could change surgical management if positive were confirmed by percutaneous biopsy. RESULTS: MRI identified additional lesions changing surgical management in 19 of 61 patients (31%) with fat density, 94/269 (35%) with scattered fibroglandular parenchyma, 89/210 (42%) with heterogeneously dense breasts, and 26/42 (62%) with dense breasts. There was a significant difference between breast density and number of additional findings on MRI (p<0.0001). Patients with dense breasts were 5.1x more likely to have additional findings on MRI in comparison to patients with fat density breasts (95% CI 2.2-12.1, p=0.0001). CONCLUSION: Patients with dense breasts are more likely to have additional findings on pre-operative breast MRI in comparison to patients with fat tissue density breasts; if selective use of pre-operative MRI is necessary, patients with dense breast tissue density seem to show the maximal benefit. HIGHLIGHTS: • Preoperative MRI detects many additional lesions not seen on mammography. • Increased breast density correlates with more findings on preoperative breast MRI (p<0.0001). • Extremely dense breasts are more likely to have additional findings on MRI. • Increased breast density is associated with more MRI findings that changed management.

Selection of symptomatic patients with Crohn's disease for abdominopelvic computed tomography: role of serum C-reactive protein.

BACKGROUND: Results of previous studies have shown that repeated abdominopelvic computed tomography (CT) examinations can lead to substantial cumulative diagnostic radiation exposure in patients with Crohn's disease (CD). Improved selection of patients referred for CT will reduce unnecessary radiation exposure. This study examines if serum C-reactive protein (CRP) concentration predicts which symptomatic patients with CD are likely to have significant disease activity or disease complications (such as abscess) detected on abdominopelvic CT. METHODS: All abdominopelvic CTs performed on patients with CD at a tertiary referral centre during the period June 2003 to June 2008 were identified. CT findings were coded by a pair of independent blinded senior radiologists for (i) small bowel luminal disease, (ii) large bowel luminal disease, (iii) mesenteric inflammatory changes, (iv) penetrating disease (fistulas, abscess, or phlegmon), (v) acute disease complications (obstruction or perforation), and (vi) acute non-CD findings. Imaging findings were correlated with serum CRP checked within 14 days before imaging. The reference range for CRP was defined as 0-5 mg/L. RESULTS: A total of 147 patients with symptomatic CD had a CRP assay performed within 14 days before undergoing abdominopelvic CT. The median time from CRP assay to imaging was 2 days (interquartile range, 0-6 days). Median CRP before imaging was 24 mg/L (interquartile range, 6-88 mg/L). CT was normal in 34 of 147 case (23.1%). Patients with normal CRP (n = 36) were significantly less likely to have penetrating disease (odds ratio [OR], 0.04 [95% confidence interval {CI}, 0.01-0.7]; P < .001) or large bowel luminal disease (OR, 0.3 [95% CI, 0.1-0.8]; P < .05). Normal CRP excluded penetrating disease with a sensitivity of 1.0 (95% CI, 0.87-1.0). CRP levels did not correlate with the presence of small bowel luminal disease (n = 82), mesenteric inflammatory changes (n = 68), or acute disease complications (n = 10). CONCLUSION: Symptomatic patients with CD and normal serum CRP are unlikely to have evidence of abscess, fistulating disease, or large bowel luminal disease detected on abdominopelvic CT. However, abdominopelvic CT may demonstrate evidence of clinically significant non-penetrating CD or complications, including perforation and acute obstruction, regardless of serum CRP concentration.