Hepatocellular Carcinoma Post Embolotherapy: Imaging Appearances and Pitfalls on Computed Tomography and Magnetic Resonance Imaging.

Embolotherapies used in the treatment of hepatocellular carcinoma (HCC) include bland embolization, conventional transarterial chemoembolization (cTACE) using ethiodol as a carrier, TACE with drug-eluting beads and super absorbent polymer microspheres (DEB-TACE), and selective internal radiation therapy (SIRT). Successfully treated HCC lesions undergo coagulation necrosis, and appear as nonenhancing hypoattenuating or hypointense lesions in the embolized region on computed tomography (CT) and magnetic resonance. Residual or recurrent tumours demonstrate arterial enhancement with portal venous phase wash-out of contrast, features characteristic of HCC, in and/or around the embolized area. Certain imaging features that result from the procedure itself may limit assessment of response. In conventional TACE, the high-attenuating retained ethiodized oil may obscure arterially-enhancing tumours and limit detection of residual tumours; thus a noncontrast CT on follow-up imaging is important post-cTACE. Hyperenhancement within or around the treated zone can be seen after cTACE, DEB-TACE, or SIRT due to physiologic inflammatory response and may mimic residual tumour. Recognition of these pitfalls is important in the evaluation embolotherapy response.

Imaging of blunt vascular neck injuries: a review of screening and imaging modalities.

OBJECTIVE: We will review the epidemiology of blunt cerebrovascular injuries (BCVIs) and the rationale for screening. Current imaging modalities used to screen for BCVIs will be discussed with an emphasis on CT angiography. CONCLUSION: Screening for BCVIs can decrease rates of postinjury complications, such as stroke. The use of standardized screening criteria and the appropriate imaging modalities can allow early detection of BCVIs and effective intervention.

Imaging of blunt vascular neck injuries: a clinical perspective.

OBJECTIVE: We will review the common injuries and anatomic distributions of blunt cerebrovascular injuries (BCVIs) of the neck, explain the grading criteria, and discuss the corresponding management. Artifacts associated with BCVI on CT will also be examined. CONCLUSION: Identifying common injury patterns and anatomic distributions associated with BCVI can help decide the grade and management earlier and reduce the risk for potential complications. Recognizing the common artifacts associated with BCVI helps the reader successfully recognize a true BCVI.

Risk-benefit analysis of pulmonary CT angiography in patients with suspected pulmonary embolus.

OBJECTIVE: The objective of our study was to estimate the mortality benefit-to-risk ratio of pulmonary CT angiography (CTA) by setting (ambulatory [emergency department or outpatient] or inpatient), age, and sex. MATERIALS AND METHODS: A retrospective evaluation of 1424 consecutive pulmonary CTA examinations was performed and the following information was recorded: examination setting, patient age, patient sex, pulmonary CTA interpretation for pulmonary embolus (PE), and CT radiation exposure (dose-length product). We estimated mortality benefit of pulmonary CTA by multiplying the rate of positive pulmonary CTA examinations by published estimates of mortality of untreated PE in ambulatory and inpatient settings. We estimated the lifetime attributable risk of cancer mortality due to radiation from pulmonary CTA by calculating the estimated effective dose and using sex-specific polynomial equations derived from the Biological Effects of Ionizing Radiation VII report. We calculated benefit-to-risk ratios by dividing the mortality benefit of preventing a fatal PE by the mortality risk of a radiation-induced cancer. RESULTS: Pulmonary CTA diagnosed PE in 188 of 1424 patients (13.2%). Both inpatients (101/723, 14.0%) and emergency department patients (74/509, 14.5%) had significantly higher rates of PE than outpatients (13/192 [6.8%]). Males received significantly (p = 0.02451) higher radiation dose (9.7 mSv) than females (8.4 mSv), but males had a significantly (p < 0.0001) lower lifetime attributable risk of cancer mortality than females. Assuming an untreated PE mortality rate of 5% for ambulatory patients and 30% for inpatients, the benefit-to-risk ratio ranged from 25 for ambulatory patients to 187 for inpatients. Ambulatory women had the lowest benefit-to-risk ratio. CONCLUSION: The benefit-to-risk ratio of pulmonary CTA in patients with suspected PE ranges from 25 to 187 and can be increased by optimizing the radiation dose.