Multisegment and halfscan reconstruction of 16-slice computed tomography for detection of coronary artery stenoses

RATIONALE AND OBJECTIVES: To compare the diagnostic accuracy and image quality of 2 reconstruction algorithms (multisegment and halfscan) for computed tomography (CT) coronary angiography in patients without beta-blocker medication. MATERIALS AND METHODS: Thirty-four patients with 42 significant coronary stenoses in 136 main coronary branches were examined using a 16-slice CT scanner (Aquilion, Toshiba, Otawara, Japan). Twenty-seven patients (79%) had heart rates above 65 beats/min. RESULTS: Without exclusion of branches the sensitivity, specificity, accuracy, and rate of nonassessable segments with multisegment versus halfscan reconstruction were 88 versus 74%, 91 versus 71%, 90 versus 72%, and 2 versus 21% (P < 0.01), respectively. Multisegment reconstruction improved the average vessel length free of motion artifacts by 56% compared with halfscan reconstruction (P < 0.01). Image quality in terms of vessel continuity and visibility of side branches (P < 0.005) was significantly better using multisegment reconstruction. CONCLUSIONS: Multisegment reconstruction has superior diagnostic accuracy and image quality compared with halfscan reconstruction in patients with normal heart rates.     

Computed Tomography-Guided Interstitial HDR Brachytherapy (CT-HDRBT) of the Liver in Patients with Irresectable Intrahepatic Cholangiocarcinoma

Purpose

This study was designed to investigate the clinical outcome of patients with irresectable, intrahepatic cholangiocarcinoma (IHC) treated with computed tomography (CT)-guided HDR-brachytherapy (CT-HDRBT) for local tumor ablation.

Method

Fifteen consecutive patients with histologically proven cholangiocarcinoma were selected for this retrospective study. Patients were treated by high-dose-rate internal brachytherapy (HDRBT) using an Iridium-192 source in afterloading technique through CT-guided percutaneous placed catheters. A total of 27 brachytherapy treatments were performed in these patients between 2006 and 2009. Median tumor enclosing target dose was 20?Gy, and mean target volume of the radiated tumors was 131 (±?90) ml (range, 10?C257?ml). Follow-up consisted of clinical visits and magnetic resonance imaging of the liver every third month. Statistical evaluation included survival analysis using the Kaplan?CMeier method.

Results

After a median follow-up of 18 (range, 1?C27) months after local ablation, 6 of the 15 patients are still alive; 4 of them did not get further chemotherapy and are regarded as disease-free. The reached median local tumor control was 10?months; median local tumor control, including repetitive local ablation, was 11?months. Median survival after local ablation was 14?months and after primary diagnosis 21?months.

Conclusion

In view of current clinical data on the clinical outcome of cholangiocarcinoma, locally ablative treatment with CT-HDRBT represents a promising and safe technique for patients who are not eligible for tumor resection.     

Cardiac and Coronary Anatomy in Computed Tomography

Noninvasive coronary angiography has become increasingly important for coronary artery assessment in recent years. Its indications include the exclusion of coronary artery disease and follow-up of patients after bypass surgery. The results can be displayed using various postprocessing techniques such as multiplanar reconstruction, maximum intensity projection, and 3D reconstruction. Adequate interpretation of the imaging findings crucially relies on good anatomic knowledge of the heart and coronary arteries, which includes knowledge of the coronary segments and normal anatomic variants.     

Safety and tolerability of iobitridol in general and in patients with risk factors: Results in more than 160 000 patients

Objective

To review the safety, the tolerability and the diagnostic effectiveness of iobitridol under daily practice conditions in the general population and at-risk patients in a post-marketing surveillance study.

Materials and methods

A total of 160 639 patients (55.1% male, 43.6% female, mean age 58.6 years) were analysed in 555 centers. Patients underwent X-ray examinations using iobitridol (Xenetix^®, Guerbet, Sulzbach, Germany) as IV contrast medium (mean volume 85.6 ml). 21.8% of all patients had at least one risk factor (e.g., renal impairment), 7.3% were at-risk patients with allergies or who had previously reacted to contrast medium. Antiallergic pretreatment before contrast medium administration was given in 1144 patients (0.7%). Adverse events were documented and the image quality was assessed.

Results

A diagnosis was possible in 99.5% of all cases. The image quality was rated good or excellent in 92.2%. The adverse event rate (e.g., nausea, urticaria) observed was 0.6% in all patients, 1.6% in patients with allergies and 6.0% in patients with a previous reaction to contrast medium. Adverse events occurred more often in women than in men (p < 0.001). Pretreatment did not decrease the rate of adverse events. The rate of adverse events was not increased in higher doses of iobitridol, even if administered to high-risk patients.

Conclusions

Iobitridol was shown to be a safe and well-tolerated contrast medium with a low incidence of adverse events in patients with and without risk factors resulting in a good or excellent image quality in most patients.     

Computed-tomography-guided high-dose-rate brachytherapy (CT-HDRBT) ablation of metastases adjacent to the liver hilum

Purpose

To evaluate technical feasibility and clinical outcome of computed tomography-guided high-dose-rate-brachytherapy (CT-HDRBT) ablation of metastases adjacent to the liver hilum.

Materials and methods

Between November 2007 and May 2012, 32 consecutive patients with 34 metastases adjacent to the liver hilum (common bile duct or hepatic bifurcation ≤5 mm distance) were treated with CT-HDRBT. Treatment was performed by CT-guided applicator placement and high-dose-rate brachytherapy with an iridium-192 source. MRI follow-up was performed 6 weeks and every 3 months post intervention. The primary endpoint was local tumor control (LTC); secondary endpoints included time to progression (TTP) and overall survival (OS).

Results

Patients were available for MRI evaluation for a mean follow-up time of 18.75 months (range: 3–56 months). Mean tumor diameter was 4.3 cm (range: 1.3–10.7 cm). One major complication was observed. Four (11.8%) local recurrences were observed after a local tumor control of 5, 8, 9 and 10 months, respectively. Twenty-two patients (68.75%) experienced a systemic tumor progression during the follow up period. Mean TTP was 12.9 months (range: 2–56 months). Nine patients died during the follow-up period. Median OS was 20.24 months.

Conclusion

Minimally invasive CT-HDRBT is a safe and effective option also for unresectable liver metastases adjacent to the liver hilum that would have been untreatable by thermal ablation.     

Hepatocellular carcinoma: computed-tomography-guided high-dose-rate brachytherapy (CT-HDRBT) ablation of large (5–7 cm) and very large (>7 cm) tumours

Objectives  

Evaluate the clinical outcome of CT-guided high-dose-rate-brachytherapy (CT-HDRBT) of hepatocellular carcinoma (HCC) larger than 5 cm in diameter with the goal of local tumour control (LTC).     

Multidetector computed tomography for preoperative assessment of hepatic vasculature and prediction of splenic artery steal syndrome in patients with liver cirrhosis before transplantation

The purpose of this study was to evaluate the accuracy of MDCT for preoperative assessment of hepatic vascular anatomy and the identification of liver-transplantation (OLT) patients at risk of developing subsequent splenic artery steal syndrome (SASS). A total of 145 patients with liver cirrhosis who had undergone OLT and had pre-operative three-phase MDCT (4- to 64-rows) within 100 days before OLT were enrolled retrospectively. MDCT and 3Ds were reviewed by two independent blinded observers (O1/O2). Pre-operative imaging findings were correlated with intra-operative results; findings indicative for SASS were correlated with clinical data and DSA. Among all 145 patients, 16 patients (11%) showed accessory hepatic arteries (accuracy O1/O2, 97%; with 3Ds, 100%); 32 (22%) patients had replaced hepatic arteries (accuracy O1, 97%; O2, 95%; with 3Ds, 100%; κ?=?0.87 and 0.89, P?<?0.001). Among 119 patients, 12 patients developed SASS after OLT. The logistic regression model revealed the spleen volume (P?=?0.0105) as a predictive factor of SASS. With spleen volumes ≥829 ml, an accuracy of 75% for prediction of SASS was obtained. MDCT with three-dimensional post-processing (3Ds) was highly accurate for pre-operative hepatic vessel evaluation in patients before OLT. In addition, spleen volume was a predictive factor for developing SASS after OLT.     

Non-cardiac findings on coronary computed tomography and magnetic resonance imaging

Both multislice computed tomography (CT) and magnetic resonance imaging (MRI) are emerging as methods to detect coronary artery stenoses and assess cardiac function and morphology. Non-cardiac structures are also amenable to assessment by these non-invasive tests. We investigated the rate of significant and insignificant non-cardiac findings using CT and MRI. A total of 108 consecutive patients suspected of having coronary artery disease and without contraindications to CT and MRI were included in this study. Significant non-cardiac findings were defined as findings that required additional clinical or radiological follow-up. CT and MR images were read independently in a blinded fashion. CT yielded five significant non-cardiac findings in five patients (5%). These included a pulmonary embolism, large pleural effusions, sarcoid, a large hiatal hernia, and a pulmonary nodule (>1.0 cm). Two of these significant non-cardiac findings were also seen on MRI (pleural effusions and sarcoid, 2%). Insignificant non-cardiac findings were more frequent than significant findings on both CT (n = 11, 10%) and MRI (n = 7, 6%). Incidental non-cardiac findings on CT and MRI of the coronary arteries are common, which is why images should be analyzed by radiologists to ensure that important findings are not missed and unnecessary follow-up examinations are avoided.