Dual-energy CT to detect recurrent HCC after TACE: initial experience of color-coded iodine CT imaging.

OBJECTIVES: To evaluate the feasibility of diagnosing recurrence of HCC after TACE color-coded iodine CT (CICT) based on arterial phase scans obtained by a dual-energy CT (DECT) scanner. METHODS: A CICT scan was acquired from an iodine map after applying material decomposition of the liver tissue and setting a threshold attenuation level for viable tumors. Two radiologists reviewed both conventional and CICT sets in 31 patients who had a history of TACE for HCC. The performances in detecting local tumor progression (LTP) were evaluated by alternative free-response receiver operating characteristics. The rate of uncertain diagnosis and interobserver agreement of the diagnosis were explored. Additionally, the reading time and radiation dose were also investigated. RESULTS: The mean figures of merit of the conventional and CICT sets for LTP were 0.818 and 0.847, respectively (p=0.459). The rate of uncertain diagnosis was significantly decreased in CICT sets (34.5% vs. 0%), and interobserver agreement was improved (k=0.527 vs. 0.718). On the CICT set, mean reading time was reduced by 49s and mean radiation dose was also decreased by 18.3% when replacing the non-contrast CT with CICT. CONCLUSIONS: CICT is comparable to conventional liver CT protocol in demonstrating viable HCCs, while it allows a reduction in radiation dose.

Changing waveform during respiration on hepatic vein Doppler sonography of severe portal hypertension: comparison with the damping index.

OBJECTIVES: The purposes of this study were to assess retrospectively whether the waveform change during respiration on hepatic vein Doppler sonography is a parameter of severe portal hypertension as estimated by the hepatic venous pressure gradient (HVPG) and to compare with a hepatic vein damping index (DI) at expiration. METHODS: Spectral Doppler sonography of the hepatic vein was performed on 22 consecutive patients who underwent HVPG measurement for portal hypertension with liver cirrhosis. From the maximum and minimum velocities of systolic hepatofugal venous flow on Doppler sonography, 3 parameters were derived: damping index at expiration (DI(exp)), damping index ratio (DI(ratio)), and damping index difference (ΔDI) between inspiration and expiration. Considering an HVPG level of 12 mm Hg or higher as the threshold level for high-grade portal hypertension, we assessed the diagnostic capability of these Doppler sonographic parameters to discriminate using receiver operating characteristic curve analysis. RESULTS: Area under the curve values for the DI(ratio) and ΔDI (0.875 and 0.889, P = .807 and .682, respectively) were slightly higher than the area for the DI(exp) (0.861; respectively). When the DI(exp) was greater than 0.56, the sensitivity and specificity for high-grade portal hypertension were 66.7% and 100.0%, respectively. In the case of the DI(ratio), the sensitivity and specificity were 77.8%, and 100.0% at greater than 0.69. The corresponding sensitivity and specificity at a value of 0.25 or less for the ΔDI were 83.3% and 100.0%. CONCLUSIONS: The ratio and difference of the DI of the hepatic vein waveform are helpful parameters in assessing the severity of portal hypertension as well as using the existing DI on its own.

Left costomediastinal recess of the pleura, the potential pleural space anterior to the heart.

OBJECTIVE: To investigate clinical implications of the left costomediastinal recess of the pleura. METHODS: The left anterior pleural anatomy was studied in 12 cadavers. Chest computed tomography (CT) scans of 68 healthy/near-healthy patients were reviewed for the recess. Twenty pleural lesions in the recess were analyzed on CT. Eight cases of left paracardiac pericardiocentesis were analyzed for pleural complications. RESULTS: Two fresh cadavers showed the recess to be wider downward, measuring 75 and 55 mm in width at the sixth intercostal space. None of the 68 healthy/near- healthy CT scans displayed the recess. Twenty recess lesions were connected to similar pleural lesions surrounding the left lung (n = 19) or showed an isolated lesion therein only partly facing the left lung (n = 1). Ipsilateral pleural effusion complicated 3 of 7, successful left paracardiac pericardiocentesis. CONCLUSION: Regardless of their contiguity with the lung, the differential diagnosis of precordial lesions should include pleural diseases in the recess. Left anterior pericardiocentesis unavoidably violates the intervening recess, sometimes causing pleural effusion.

Omental mesothelial cyst herniated to the thorax through the esophageal hiatus: a case report.

Both mesothelial cyst in the omentum and omental herniation through the esophageal hiatus without abdominal visceral involvement are rare. We report a case of omental mesothelial cyst herniated to the thorax through the esophageal hiatus.

Rib xanthoma resected by video-assisted thoracoscopic surgery using a bone punch.

Xanthomas of the rib are extremely rare benign neoplasms, most commonly reported in soft tissue, but rarely in bone. We report a case of a 4-cm xanthoma of the rib resected by video-assisted thoracoscopic surgery and pulled through a 2-cm port incision around the patient's areola. To the best of our knowledge, there are only 8 other such cases, and none of which were removed by thoracoscopic surgery.

Radiographic and CT findings of thoracic complications after pneumonectomy.

Pneumonectomy is the treatment of choice for bronchogenic carcinoma and intractable end-stage lung diseases such as tuberculosis and bronchiectasis, but it is often followed by postoperative complications, which account for significant morbidity and mortality. Knowledge of the radiologic features of such complications is of critical importance for their early detection and prompt management. Complications of pneumonectomy are classified as early or late, depending on when they occur in relation to the hospitalization period. Early complications of pneumonectomy include pulmonary edema, bronchopleural fistula, pneumonia of the contralateral lung, empyema, and adult respiratory distress syndrome, which may occur separately or in combination. Late postpneumonectomy complications include recurrent disease, infection, effects of radiation therapy or chemotherapy, and surgical complications such as late-onset bronchopleural fistula, postpneumonectomy syndrome, and esophagopleural fistula. Sequential examinations with chest radiography after pneumonectomy are an invaluable method of screening for these complications, especially in the early postoperative period. When the radiographic findings are inconclusive, computed tomography is helpful for establishing a diagnosis and obtaining detailed information about the disease process.

CT analysis of the anterior mediastinum in idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia.

OBJECTIVE: We wanted to determine whether the amount and shape of the anterior mediastinal fat in the patients suffering with usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) was different from those of the normal control group. MATERIALS AND METHODS: We selected patients who suffered with UIP (n = 26) and NSIP (n = 26) who had undergone CT scans. Twenty-six controls were selected from individuals with normal CT findings and normal pulmonary function tests. All three groups (n = 78) were individually matched for age and gender. The amounts of anterior mediastinal fat, and the retrosternal anteroposterior (AP) and transverse dimensions of the anterior mediastinal fat were compared by one-way analysis of variance and Bonferroni's test. The shapes of the anterior mediastinum were compared using the Chi-square test. Exact logistic regression analysis and polychotomous logistic regression analysis were employed to assess whether the patients with NSIP or UIP had a tendency to show a convex shape of their anterior mediastinal fat. RESULTS: The amount of anterior mediastinal fat was not different among the three groups (p = 0.175). For the UIP patients, the retrosternal AP dimension of the anterior mediastinal fat was shorter (p = 0.037) and the transverse dimension of the anterior mediastinal fat was longer (p = 0.001) than those of the normal control group. For the NSIP patients, only the transverse dimension was significantly longer than those of the normal control group (p < 0.001). The convex shape of the anterior mediastinum was predictive of NSIP (OR = 19.7, CI 3.32-infinity, p < 0.001) and UIP (OR = 24.42, CI 4.06-infinity, p < 0.001). CONCLUSION: For UIP patients, the retrosternal AP and transverse dimensions are different from those of normal individuals, whereas the amounts of anterior mediastinal fat are similar. UIP and NSIP patients have a tendency to have a convex shape of their anterior mediastinal fat.

Coronary artery anomalies: classification and ECG-gated multi-detector row CT findings with angiographic correlation.

Congenital abnormalities of the coronary arteries are an uncommon but important cause of chest pain and, in some cases of hemodynamically significant abnormalities, sudden cardiac death. For several decades, premorbid diagnosis of coronary artery anomalies has been made with conventional angiography. However, this imaging technique has limitations due to its projectional and invasive nature. The recent development of electrocardiographically (ECG)-gated multi-detector row computed tomography (CT) allows accurate and noninvasive depiction of coronary artery anomalies of origin, course, and termination. Multi-detector row CT is superior to conventional angiography in delineating the ostial origin and proximal path of an anomalous coronary artery. Familiarity with the CT appearances of various coronary artery anomalies and an understanding of the clinical significance of these anomalies are essential in making a correct diagnosis and planning patient treatment.

Differentiation of recently infarcted myocardium from chronic myocardial scar: the value of contrast-enhanced SSFP-based cine MR imaging.

The purpose of this study is to demonstrate whether the signal intensity (SI) of myocardial infarction (MI) on contrast enhanced (CE)-cine MRI is useful for differentiating recently infarcted myocardium from chronic scar. This study included 24 patients with acute MI (36-84 years, mean age: 57) and 19 patients with chronic MI (44-80 years, mean age: 64). The diagnosis of acute MI was based on the presence of typical symptoms, i.e. elevation of the cardiac enzymes and the absence of any remote infarction history. The diagnosis of chronic MI was based on a history of MI or coronary artery disease of more than one month duration and on the absence of any recent MI within the previous six months. Retrospectively, the ECG-gated breath-hold cine imaging was performed in the short axis plane using a segmented, balanced, turbo-field, echo-pulse sequence two minutes after the administration of Gd-DTPA at a dose of 0.2 mmol/kg body weight. Delayed contrast-enhanced MRI (DCE MRI) in the same plane was performed 10 to 15 minutes after contrast administration, and this was served as the gold standard of reference. The SI of the infarcted myocardium on the CE-cine MRI was compared with that of the normal myocardium on the same image. The area of abnormal SI on the CE-cine MRI was compared with the area of hyperenhancement on the DCE MRI. The area of high SI on the CE-cine MRI was detected in 23 of 24 patients with acute MI (10 with homogenous high SI, 13 high SI with subendocardial low SI, and one with iso SI). The area of high SI on the CE-cine MRI was larger than that seen on the DCE MRI (p < 0.05). In contrast, the areas of chronic MI were seen as iso-SI with thin subendocardial low SI on the CE-cine MR in all the chronic MI patients. The presence of high SI on both the CE-cine MRI and the DCE MRI is more sensitive (95.8%) for determining the age of a MI than the presence of myocardial thinning (66.7%). This study showed the different SI patterns between recently infarcted myocardium and chronic scar on the CE-cine MRI. CE-cine MRI is thought to be quite useful for determining the age of myocardial infarction, in addition to its utility for assessing myocardial contractility.

Pulmonary parenchymal involvement of low-grade lymphoproliferative disorders.

Lymphoid tissue is a normal component of the lung. The various lymphoproliferative diseases affect the lung parenchyma. The purpose of this article is to classify various lymphoproliferative diseases and to understand their computed tomography features of pulmonary involvement. The examples include follicular bronchiolitis, lymphocytic interstitial pneumonia, plasma cell granuloma, Castleman disease, lymphomatoid granulomatosis, and mucosa-associated lymphoid tissue lymphoma. Pathologic correlation is helpful for understanding imaging findings and their pathophysiology.

Pulmonary tuberculosis: another disease showing clusters of small nodules.

OBJECTIVE: Pulmonary sarcoidosis was recently reported to show the "sarcoid galaxy" sign, indicating large pulmonary nodules composed of coalescent small nodules. The purpose of this study was to review cases of pulmonary tuberculosis showing CT features indistinguishable from the sarcoid galaxy sign. CONCLUSION: Large nodules arising from the coalescence of small nodules may be seen in active tuberculosis and in sarcoidosis. The CT finding was termed "clusters of small nodules" instead of the "sarcoid galaxy sign" in this article. A single cluster of small nodules, clusters of small nodules in the superior segment of the lower lobe, or clusters of small nodules not associated with lymphadenopathy or associated with tree-in-bud lesions would favor the diagnosis of active pulmonary tuberculosis rather than pulmonary sarcoidosis.