Brad Thompson

Multicenter clinical trial of ultrasmall superparamagnetic iron oxide in the evaluation of mediastinal lymph nodes in patients with primary lung carcinoma

The purpose of this study was to evaluate the clinical efficacy of ultrasmall superparamagnetic iron oxide particles as a magnetic resonance (MR) contrast agent in differentiating metastatic from benign lymph nodes. Eighteen patients with primary lung malignancy and suspected regional lymph node metastases underwent MR imaging before and after Combidex® infusion in a multi‐institutional study. All MR sequences were interpreted by one or more board‐certified radiologists experienced in imaging thoracic malignancy. Each patient was evaluated for the number and location of lymph nodes, homogeneity of nodal signal, and possible change of MR signal post contrast. All patients underwent resection or sampling of the MR‐identified lymph node(s) 1–35 day(s) post contrast MR imaging. In all, 27 lymph nodes or nodal groups were available for histopathologic correlation. Combidex had a sensitivity of 92% and a specificity of 80% in identifying pathologically confirmed metastatic mediastinal lymph nodes. Based on our preliminary data, Combidex MR imaging may provide additional functional information useful in the staging of mediastinal lymph nodes. J. Magn. Reson. Imaging 1999;10:468–473.

Kawasaki disease: role of coronary CT angiography

Invasive coronary angiography is considered to be the gold standard for diagnosis and follow-up of coronary artery aneurysms, thrombosis and stenosis in patients with Kawasaki Disease. However, the availability of multi-detector CT coronary angiography provides a viable alternative as a non-invasive imaging modality for sequential follow-up of patients with Kawasaki disease. High quality multidetector CT angiography images of coronary arterial anatomy can be obtained after adequate heart rate control using beta blockers.

Imaging of coronary calcification by computed tomography.

As an unequivocal biomarker for arteriosclerosis, the presence of coronary calcium serves as a qualitative reflection of the severity of coronary artery disease (CAD). Greater calcium burdens correlate with more advanced disease, a higher likelihood of coronary stenoses, and a higher risk for coronary heart disease (CHD). Empirically, the quantification of coronary calcium not only provides an accurate reflection of disease severity, but also has great potential as a screening tool for CHD. Computed tomography (CT) has been shown to be capable of providing accurate, noninvasive measurements of coronary calcification. Evidence shows that calcium measurements by CT correlate well with histological plaque analyses, and that calcium burdens accurately reflect disease severity and can be used to assess individual risk for CHD. The purpose of this review article is to examine the accumulated evidence that has attempted to validate CT as a diagnostic tool for CAD and as a screening exam for CHD. J. Magn. Reson. Imaging 2004;19:720–733.

Identifying left lower lobe pneumonia at chest radiography: Performance of family practice residents before and after a didactic session

RATIONALE AND OBJECTIVESnThe authors sought to determine whether the lateral chest radiograph is helpful in identifying left lower lobe pneumonia among inexperienced readers.nnnMATERIALS AND METHODSnThe authors selected all patients who presented to a family practice training program with radiologic and clinical evidence of left lower lobe pneumonia (n = 65). They then selected an equal number of patients in whom chest radiographs were taken to rule out pneumonia and were found to be normal. Eight 1st-year family practice residents were asked to read the radiographs before and after a didactic session that emphasized lateral chest radiograph interpretation. The radiographs were presented under two viewing conditions: posteroanterior (PA) only versus PA and lateral. Receiver operating characteristic (ROC) curve methods were used to compare the effect of both the didactic session and the viewing condition on diagnostic accuracy.nnnRESULTSnThere were no significant differences in performance before and after the didactic session and no differences between the two viewing conditions. After including only abnormal radiographs that demonstrated the spine sign (an apparent increased opacification of the lower vertebral bodies on the lateral view), the residents performed better when presented with both PA and lateral radiographs than when presented with the PA radiograph only (area under ROC curve, .8158 vs .7418, respectively; P = 0.24).nnnCONCLUSIONnIn patients with left lower lobe pneumonia whose radiographs demonstrated the spine sign, diagnostic accuracy improved when the lateral chest radiograph was viewed.

Preablation assessment for the left atrium: comparison of ECG-gated cardiac CT with echocardiography.

RATIONALE AND OBJECTIVESnEvaluate the role of two-dimensional echocardiography and electrocardiographically (ECG)-gated contrast-enhanced multislice computed tomographic (MSCT) cardiac imaging to assess cardiac anatomy, specifically pulmonary venous anatomy and left atrial thrombus, in a selected group of patients before catheter-based atrial fibrillation ablation.nnnMATERIALS AND METHODSnLeft atrial anatomy and associated findings in 34 consecutive patients scheduled for electrophysiologic testing who underwent both echocardiography and ECG-gated 16-slice MSCT cardiac imaging were retrospectively compared. Results from two-dimensional transthoracic echocardiography (TTE), cardiac MSCT, electrophysiologic study (EPS), and transesophageal echocardiography (TEE) (when performed) were taken from the official medical record without prior knowledge of this study when interpretation was rendered for clinical use. Electronic record review included: presence of left atrial thrombus (defined as constant filling defect on at least two echocardiographic views or filling defect on computed tomography) and location, pulmonary venous anatomy, and other cardiac, mediastinal, or pulmonary abnormalities.nnnRESULTSnLeft atrial thrombus was identified by cardiac MSCT alone in five patients (15%). Pulmonary venous variants were identified with cardiac MSCT in two patients (6%). Both MSCT and echocardiography were normal in 17 subjects (79%). Echocardiography was better at identifying associated valvular abnormalities that were seen in 10 patients (29%). Cardiac MSCT angiography alone identified other cardiac and noncardiac abnormalities, including suspicious pulmonary malignancy, mediastinal adenopathy, and coronary stenosis in 15 patients (44%).nnnCONCLUSIONSnEchocardiography and cardiac MSCT angiography often provide complimentary findings during the preprocedural evaluation for patients with atrial fibrillation requiring ablation. Cardiac MSCT may provide significant additional information about the left atrium, mediastinum, coronary circulation, and visualized lung fields. Based on this study, we would advise that patients considered for radiofrequency ablation for uncontrolled right atrial fibrillation have both echocardiography and ECG-gated contrast-enhanced cardiac MSCT performed as part of the preprocedure evaluation.

Multislice computed tomography angiography of Ebstein anomaly and anomalous coronary artery

1 A 31-year-old man presented with increasing palpitaions, chest tightness, and worsening dyspnea on exertion. oronary angiography showed an anomalous coronary arery from the right coronary cusp supplying the mid and istal left anterior descending (LAD) artery. Multislice omputed tomography (MSCT) angiogram was performed o assess the precise course of the anomalous coronary rtery. MSCT showed an anomalous LAD coronary artery rising from the right coronary artery coursing anterior to he right ventricular outflow tract before descending into the nterior interventricular groove (Fig 1). However, CT also howed a small right ventricle, apical displacement of the eptal leaflet, large sail-like anterior leaflet, and “atrializaion” of the right ventricle (which is cephalad to the septal eaflet of the tricuspid valve and caudal to the anatomic