Wei-Lin Tsai

CT-Guided Core Biopsy of Lung Lesions: A Primer

OBJECTIVE CT-guided core biopsy is playing an increasing role in the diagnosis of benign disease, cellular differentiation, somatic mutation analysis, and molecular fingerprint analysis. CONCLUSION In this article, we summarize the basic concepts, protocols, and techniques that we use for CT-guided core biopsy of lung lesions to assist radiologists in obtaining diagnostic specimens while reducing preventable complications.

Contrast enhancement in cardiac MDCT: comparison of iodixanol 320 versus iohexol 350.

OBJECTIVE The objective of our study was to evaluate whether iodixanol 320 mg I/mL (iodixanol 320), with the highest iodine concentration of dimeric nonionic contrast agents on the market, results in decreased vascular or myocardial enhancement compared with iohexol 350 mg I/mL (iohexol 350). SUBJECTS AND METHODS During a 4-month period, 72 patients referred for cardiac MDCT were consecutively enrolled and randomized into two groups: iohexol 350 and iodixanol 320. The injection and scanning protocols were the same for both groups. Enhancement of the right heart, left heart, coronary arteries, and left ventricular (LV) myocardium in both the arterial and delayed phases was compared using two-tailed independent Students t test. RESULTS Enhancement in the right heart, left heart, coronary arteries, and LV myocardium in the arterial phase showed no statistical difference (p > 0.05) between the two groups, although the iohexol group showed slightly higher enhancement (average, 11.2 H) in all of the areas. Surprisingly, in the delayed phase, the iodixanol group displayed significantly higher (7.7 H) persistent enhancement (p < 0.05) in the LV myocardium. CONCLUSION Iodixanol 320 can provide vascular enhancement in cardiac MDCT that is similar to iohexol 350. In the delayed phase, iodixanol 320 shows significantly higher delayed enhancement (7.7 H) in the LV myocardium than iohexol 350.

Use of 40-detector row computed tomography before catheter coronary angiography to select early conservative versus early invasive treatment for patients with low-risk acute coronary syndrome.

Objective: Using catheter coronary angiography (CAG) as reference standard, we examined the agreement of 40-detector row computed tomography (MDCT) in triaging patients into the 2 controversial strategies of managing low-risk acute coronary syndrome (ACS). Methods: Seventy-eight patients with low-risk ACS received both MDCT and CAG. Early invasive strategy was assigned for the patient if there was significant stenosis (≥50% diameter stenosis) in any of the coronary artery segments with diameter larger than 1.5 mm. The results of MDCT were compared with the CAG for agreement. Results: The overall agreement of the early conservative/early invasive strategy assignment was 92.3%, with &kgr; value of 0.82 between MDCT and CAG. Only 1 patient needing early invasive strategy was missed by MDCT. Conclusion: Forty-detector row computed tomography is reliable in triaging patients into the 2 strategies of managing low-risk ACS.

Comprehensive MDCT Evaluation of Patients With Pulmonary Hypertension: Diagnosing Underlying Causes With the Updated Dana Point 2008 Classification

OBJECTIVE Pulmonary hypertension is a challenge for imagers and clinicians, with a variety of possible underlying causes, each with its own specific treatment. Although the diagnosis is based on physiologic measurements, ECG-gated MDCT can play a vital role in elucidating underlying cardiac, vascular, and pulmonary causes. CONCLUSION A revised system for pulmonary hypertension, the Dana Point classification, can provide a template for review of the myriad causes of this complex condition.

Arteriovenous Fistula and Graft Evaluation in Hemodialysis Patients Using MDCT: A Primer

OBJECTIVE Patent arteriovenous fistula (AVF) is related to better prognosis and quality of life for patients on long-term dialysis. When AVF dysfunction is suspected, MDCT is a good noninvasive tool for evaluating the entire AVF structure and determining reversible conditions for treatment. The aim of this article is to introduce the scanning and interpretation techniques and to illustrate the conditions related to early and late fistula failures. CONCLUSION MDCT is a fast, noninvasive, and accurate technique for diagnosing AVF complications. Radiologists familiar with these techniques can help to improve the prognosis and quality of life for hemodialysis patients.

Comprehensive MDCT Evaluation of Patients With Suspected May-Thurner Syndrome

OBJECTIVE The purpose of this essay is to introduce the MDCT protocol and interpretation techniques for optimal evaluation of patients with suspected May-Thurner syndrome. CONCLUSION May-Thurner syndrome is always the working diagnosis when a patient presents with unilateral left lower limb swelling without signs of infection. MDCT is useful for fast, comprehensive evaluation of the vascular system to determine whether May-Thurner syndrome or an alternative condition is present.

Comprehensive evaluation of patients suspected with deep vein thrombosis using indirect CT venography with multi-detector row technology: from protocol to interpretation

With the increased availability of multi-detector row CT, indirect CT venography has become an important non-invasive image modality for patients with suspected deep vein thrombosis. Use of indirect CT venography can not only diagnose/exclude deep vein thrombosis, but can also determine if there are other anomalies or diseases which might contribute to the patient’s symptoms. In this pictorial essay, we introduce the scanning protocol, post-processing techniques, and interpretation algorithm used in widely available 64 multi-detector row technology. We discuss several cases, including deep vein thrombosis in acute and chronic stages, anatomic variation, vena cava filter, and collateral veins. Lastly, we consider alternative diagnoses including varicose veins, infection, prosthesis failure of arthroplasty, traumatic vessel injury, and other musculoskeletal conditions. Radiologists should be familiar with the comprehensive interpretation of indirect CT venography to facilitate differential diagnosis and further treatment decision.

Comprehensive evaluation of CT pulmonary angiography for patients suspected of having pulmonary embolism

Recently, CT pulmonary angiography (CTPA), especially performed with multi-detector row CT, has become a key imaging modality for pulmonary embolism. However, CTPA that was performed under clinical suspicion of pulmonary embolism has been shown to lead to high prevalence of alternative diagnosis, up to 25.4%. A comprehensive evaluation of pulmonary and extrapulmonary abnormalities including cardiovascular lesions is critical in proper diagnosis and patient care. Radiologists should be familiar with the comprehensive interpretation of CTPA to facilitate differential diagnosis and further treatment decision.

Comprehensive Evaluation of Patients With Suspected Prosthetic Heart Valve Disorders Using MDCT

OBJECTIVE Early diagnosis of prosthetic valve disorders is very important in reducing morbidity and mortality of patients with a replaced heart valve. Recently, MDCT has become an important noninvasive problem-solving tool in clinical practice. This article will introduce the scanning technique, interpretation algorithm, and image findings of many valvular and extravalvular diagnoses. CONCLUSION With proper scanning technique and interpretation, MDCT can be a powerful technique for prosthetic heart valve evaluation.