Faculty Bibliography

PURPOSE: The objective of this study is to evaluate the effectiveness of nonelectrocardiographic gated multidetector computed tomography (MDCT) performed for the purpose of assessment of pulmonary embolus in the evaluation of myocardial infarction (MI). METHODS: We retrospectively evaluated 147 consecutive patients who had a computed tomography angiogram for pulmonary embolus on a 16-detector MDCT. Of this cohort, we determined 11 patients to have acute MIs based on electrocardiogram, positive troponin levels, and clinical findings and history. Four additional patients were found to have chronic MI based on history. The MDCT data were evaluated by an attending Radiologist, blinded to the clinical data, for quantitative and qualitative attenuations. Each MI was assigned a region of the heart based on its anatomical sections. RESULTS: We were able to detect 10 of 15 MIs, resulting in an overall sensitivity and specificity of 66.6% and 91.4%, respectively. The overall accuracy was 76.7%. If non-Q wave MIs are excluded from the data set, the sensitivity increased to 76.9%. Quantitative analysis of each region of the heart showed that there was a statistically significant difference (P < 0.01) between the infracting regions of the heart (69 +/- 3.3 SEM) and those with normal perfusion (93.3 +/- 1.0 SEM). CONCLUSIONS: While this method did prove to be effective at determining patients who had an MI, the low sensitivity and inability to differentiate chronic from acute myocardial infarction suggest that this technique is very limited in clinical practice.

We present 2 patients with chronic lymphocytic leukemia infiltration of the lung resulting in centrilobular nodularity on computed tomography. We present the x-ray and computed tomography patterns with pathological findings in these cases.

OBJECTIVE: Recently there has been a significant increase in the use of CT imaging resulting in a significant increase in radiation exposure to the population. Few studies have compared the degree of radiation exposure among the currently available MDCT units. Our objective is to make such a comparison. MATERIALS AND METHODS: Using a Rando anthropomorphic phantom, we placed thermoluminescent dosimeters into the center, anterior, and lateral aspect of the lower chest of the phantom. Standard CT of the chest was performed with the current protocols used at our institution on 4-, 8-, and 16-MDCT GE Healthcare systems. Next, near-identical CT scans of the entire chest were performed on the same CT systems. RESULTS: The 4-detector array showed statistically significantly higher radiation dose compared with the 16-detector array with near-identical technique (p < 0.01). There is a trend toward decreasing radiation dose with the increasing number of detectors using both standard and near-identical technique. An inverse relationship exists between measured radiation dose and the number of detectors. CONCLUSION: We theorize that as the number of detectors increases, there is a decrease in the amount of nonutilized radiation exposure, thus resulting in a lower total radiation dose.

RATIONALE AND OBJECTIVES: To evaluate the potential use of gadolinium (Gd)-based contrast media, especially that of Gadovist, a 1-molar Gd medium, in computed tomography (CT) and compare our findings with standard iodinated contrast media. MATERIAL AND METHODS: Using a live rabbit and an acrylic CT body phantom for comparative CT imaging of Gd- and I-based media. The images were acquired at 80, 100, and 120 kVp, using fixed standard beam filtration. The phantom study used serial dilutions of the Magnevist and Ultravist 300 (2.4-molar I), whereas the animal study used different volumes of Gadovist, Magnevist (0.5 molar Gd), and Ultravist administered intravenously. RESULTS: At 80 kVp for the same injection volumes of Gadovist and Ultravist, the image contrast enhancement of the aorta with Gadovist was 40% lower than that of Ultravist. In the phantom studies, however, for the same kVp settings the CT image contrast was up to fourfold higher for Gd compared with iodine when comparing the same molar concentrations of the two elements in the solutions. CONCLUSION: These results indicate a potential of Gd-based media for clinical CT angiography and provide incentive for further investigation of this subject.

We describe the design and testing of an inductive coupling system used to power an implantable minipump for applications in ambulating rats. A 2 MHz class-E oscillator driver powered a coil transmitter wound around a 33-cm-diameter rat cage. A receiver coil, a filtered rectifier, and a voltage-sensitive switch powered the implant. The implant DC current at the center of the primary coil (5.1 V) exceeded the level required to activate the solenoid valve in the pump. The variations of the implant current in the volume of the primary coil reflected the variations of the estimated coupling coefficient between the two coils. The pump could be activated in-vivo, while accommodating the vertical and horizontal movements of the animal. Advantages of this design include a weight reduction for the implant, an operation independent from a finite power source, and a remote activation/deactivation.

Congestive heart failure may be caused by late left ventricular (LV) dilation following anterior infarction. Early reperfusion prevents transmural necrosis, and makes the infarcted segment akinetic rather than dyskinetic. Surgical ventricular restoration (SVR) reduces LV volume and creates a more elliptical chamber by excluding scar in either akinetic or dyskinetic segments. The international RESTORE group applied SVR in a registry of 1198 post-infarction patients between 1998 and 2003. Early and late outcomes were examined and risk factors identified. Concomitant procedures included coronary artery bypass grafting in 95%, mitral valve repair in 22%, and mitral valve replacement in 1%. Overall 30-day mortality after SVR was 5.3% (8.7% with mitral repair vs. 4.0% without repair, p < .001) Perioperative mechanical support was uncommon (< 9%). Global systolic function improved pos toperatively, as ejection fraction increased from 29.6 +/- 11.0% to 39.5 +/- 12.3% (p < .001) and left ventricular end systolic volume index decreased from 80.4 +/- 51.4 ml/m² to 56.6 +/- 34.3 ml/m² (p < .001). Overall 5-year survival was 68.6 +/- 2.8%, Logistic regression analysis identified EF <= 30%, LVESVI >= 80 ml/m², advanced NYHA functional class, and age >=75 years as risk factors for death. Five-year freedom from hospital readmission for CHF was 78%. Preoperatively, 67% of patients were class III or IV, and postoperatively 85% were class I or II. SVR improves ventricular function and is highly effective therapy in the treatment of ischemic cardiomyopathy with excellent 5-year outcome.

Merkel Cell Carcinoma (MCC) is a rare neuroendocrine tumor of the skin which has a histological appearance similar to small cell carcinoma of the lung. This case presents a patient with cardiac tamponade from a metastatic MCC to the pericardium. To my knowledge metastatic MCC to the pericardium has not been described in the past. This case will focus on the imaging findings and the differential diagnosis of pericardial masses

This case demonstrates hypermetabolic activity in a pulmonary round infarct secondary to dirofilariasis. This case further illustrates that pulmonary dirofilariasis, like other infectious causes of pulmonary nodules, can be PET positive.