Computed Tomography Appearance of Unusual Nonaortic Thoracic Aneurysms and Pseudoaneurysms.

Although aneurysms of the thoracic aorta are easily recognized on computed tomography (CT), nonaortic intrathoracic aneurysms and pseudoaneurysms are unusual and not often encountered by radiologists. These lesions can result in complications such as hemorrhage or symptoms from mass effect. In some cases, patients may be asymptomatic and the aneurysms may represent incidental findings. Radiologists should be familiar with the CT appearances of these rare vascular abnormalities to enable prompt diagnosis. The goals of this pictorial essay are to: (1) illustrate and describe the CT appearances of various unusual intrathoracic nonaortic aneurysms and pseudoaneurysms; (2) discuss the etiology and clinical significance of these lesions; and (3) discuss management options where appropriate.

Assessment of liver fat in an obese patient population using noncontrast CT fat percent index.

OBJECTIVE: To develop a simplified method to quantify liver fat using computed tomography (CT) fat % index (CTFPI) compared to liver spleen method (CTL/S, CTL-S). METHODS: Noncontrast CT of the liver was performed in 89 patients (overweight, obese, severely obese) to quantify fat, using the following: CTFPI=[(65-patient HU)/65]×100, normal live r=65 HU. RESULTS: There was a strong linear correlation between CTFPI and the standard method of assessing liver fat using CTL/S (r=-0.901), CTL-S (r=-0.911). Hepatic HU and CTFPI were significantly different in the severely obese group compared to other two groups (P<.05). CONCLUSION: Significant correlation indicates equal diagnostic accuracy of the two methods in appropriately calibrated scanners.

Comparison of coronary plaque subtypes in male and female patients using 320-row MDCTA.

OBJECTIVE: Determine plaque subtype and volume difference in male and female patients with obstructive and non-obstructive CAD using 320-row MDCTA. MATERIALS AND METHODS: 128 patients with suspected CAD underwent MDCTA. All studies were divided into two groups based on disease severity. 0-70% stenosis (non-obstructive CAD) & >70% (obstructive). All were compared for plaque quantity and subtypes by gender. Main arteries, RCA, LM, LAD and LCX were analyzed using Vitrea 5.2 software to quantify fatty, fibrous and calcified plaque. Thresholds for coronary plaque quantification (volume in mm(3)) were preset at 35 ± 12 HU for fatty, 90 ± 24 HU for fibrous and >130 HU for calcified/mixed plaque and analyzed using STATA software. RESULTS: Total plaque burden in 118 patients [65M: 53F] was significantly higher in all arteries in males compared to females with non-obstructive disease. Total plaque volume for males vs. females was: RCA: 10.10 ± 5.02 mm(3) vs. 6.89 ± 2.75 mm(3), respectively, p = 0.001; LAD: 7.21 ± 3.38 mm(3) vs. 5.89 ± 1.93 mm(3), respectively, p = 0.04; LCX: 9.13 ± 3.27 mm(3) vs. 7.16 ± 1.73 mm(3), respectively, p = 0.002; LM 15.13 ± 4.51 mm(3) vs. 11.85 ± 4.03 mm(3), respectively, p = 0.001. In sub-analyses, males had significantly more fibrous and fatty plaque in LM, LAD & LCX than females. However in the RCA, only fibrous plaque was significantly greater in males. Calcified plaque volume was not significantly different in both genders. Only 8% of patients had obstructive CAD (>70% stenosis); there was no significant difference in plaque volume or subtypes. CONCLUSION: In patients with non-obstructive CAD, males were found to have significantly higher total coronary plaque volume with predominance of fibrous and fatty subtypes compared to females of the same age and BMI. There was no significant difference in plaque subtype or volume in patients with obstructive disease.