Soon Joo Cha

Prediction of microvascular invasion of hepatocellular carcinoma: Usefulness of peritumoral hypointensity seen on gadoxetate disodium‐enhanced hepatobiliary phase images

To determine whether peritumoral hypointensity seen on hepatobiliary phase images of preoperative gadoxetate disodium‐enhanced magnetic resonance imaging (EOB‐MRI) is useful for predicting microvascular invasion of hepatocellular carcinoma (HCC).

Uniform Image Quality Achieved by Tube Current Modulation Using SD of Attenuation in Coronary CT Angiography

OBJECTIVE The objective of our study was to evaluate whether the SD of CT attenuation values obtained from unenhanced scans of the left atrium is a reliable parameter for the individual modulation of tube current to achieve uniform image quality in coronary CT angiography (CTA). MATERIALS AND METHODS One hundred patients (59 men and 41 women) who were suspected to have coronary artery disease underwent coronary CTA using a 64-MDCT scanner. In addition to clinical studies, we also performed measurements on water phantoms. Tube current was modulated by the SD of the CT attenuation values measured from the left atrium on unenhanced images scanned at 300 mA. A modulation table was created from data obtained from the studies of water phantoms scanned at various tube currents. Other scanning parameters were identical to those used to obtain unenhanced and contrast-enhanced studies of the 100 patients. The SD values were measured from images scanned at an adjusted tube current, and the images of normal coronary and internal mammary arteries were graded. Radiation doses measured using the volume CT dose index (CTDI(vol)) were compared between the SD of the CT attenuation values and the modulation parameters suggested by the manufacturer of the scanner. RESULTS Image quality was rated as grade 3 (low mottle) on a 4-grade scale by four observers for 92-94 of the 100 patients (average, 92.5%). The mean SD value at an adjusted tube current was 12.1 H with an SD of 0.758 H (target SD = 12 H). A radiation dose reduction of 9-45% was achieved in patients grouped by weight who weighed less than 70 kg, and a reduction of up to 71% was seen in individual cases. CONCLUSION Modulating tube current using the SD of CT attenuation values from the left atrium is a highly reliable method of achieving uniform image quality in coronary CTA.

Coronary Stent Fracture: Detection with 64-Section Multidetector CT Angiography in Patients and in Vitro

PURPOSE To evaluate 64-section multidetector coronary computed tomographic (CT) angiography for the depiction of coronary stent fracture in patients and in vitro. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and informed patient consent was waived. The coronary CT angiograms obtained in 371 consecutive patients (268 men, 103 women; mean age, 62.9 years) with 545 stents were reviewed. All patients with stent fractures underwent conventional coronary angiography and/or fluoroscopy as part of their medical care. In phantom studies, magnified radiographs of three types of drug-eluting stents in their fully expanded, maximally bent, and unrolled states were obtained. CT angiography and fluoroscopy of a water phantom that contained two drug-eluting stents--Cypher and Taxus devices--with four fractures each were performed, and two radiologists blinded to the fracture information evaluated the images. RESULTS Twenty-four stents with fractures were identified. Eighteen fractured stents (13 Cypher, four Taxus, one S670) in 14 patients were detected with CT angiography; six (33%; two Cypher, four Taxus) of these 18 stents in five (36%) patients were not detected on conventional angiograms at the initial readings. Six fractured stents showed significant (>50%) recurrent in-stent stenosis. Of 58 arteries with overlapping stent placements, eight (14%) had fractures involving 11 stents. In the in vitro studies, 57 stent fractures (31 Cypher, 26 Taxus) were detected with CT angiography and 38 (18 Cypher, 20 Taxus) were detected with fluoroscopy. CONCLUSION Coronary CT angiography depicts stent fractures in patients and phantoms, even those fractures that are not clearly depicted by conventional angiography. SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/249/3/810/DC1.

Coronary-to-bronchial artery fistula: demonstration by 64-multidetector computed tomography with retrospective electrocardiogram-gated reconstructions.

Objective: The aim of this study was to evaluate the incidence of coronary-to-bronchial artery fistula (CBF) and clinical significance in 1300 patients examined with 64-multidetector computed tomography (MDCT) coronary angiography. Methods: One thousand three hundred ten patients underwent coronary MDCT for atypical chest pain or screening. Volume-rendering and multiplanar reconstruction images were reviewed, and subsequent cineangiographies were compared. Results: Eight cases of CBF were detected-6 originated from the left circumflex artery, and 2 originated from the right coronary artery. A hypertrophied anomalous branch of left circumflex artery was observed in 1 case, and underlying bronchiectasis was noted. Seven cases had a thin-wall communicating vessel. Subsequent cineangiography revealed identical appearance with MDCT reconstruction images. Conclusions: The incidence of CBF (0.61%) in this study is similar to those of a few cineangiographic studies in the literature. Our study showed that 64-MDCT coronary angiography is an accurate and noninvasive tool for detection of CBF.

Primary Mucinous Adenocarcinoma of a Seminal Vesicle Cyst Associated with Ectopic Ureter and Ipsilateral Renal Agenesis: a Case Report

Primary adenocarcinoma of the seminal vesicles is a rare neoplasm. Congenital seminal vesicle cysts are commonly associated with unilateral renal agenesis or dysgenesis. To the best of our knowledge, mucinous adenocarcinoma of the seminal vesicle cyst thats associated with an ectopic ureter opening into the seminal vesicle and ipsilateral renal agenesis has not been described in the radiological literature. We report here on the radiological findings of a primary adenocarcinoma of a seminal vesicle cyst in this condition.

CT features of torsion of benign cystic teratoma of the ovary

PURPOSE The purpose of this work was to evaluate the usefulness of CT scans for distinguishing torsed from uncomplicated benign cystic teratoma (BCT). METHOD Retrospective analysis was performed in 14 torsed BCTs (14 patients) and in 23 uncomplicated BCTs (20 patients) for comparison. The features on CT scans were compared to the pathologic findings. RESULTS CT findings indicating torsed BCT were the presence of eccentric wall thickening of >1 cm, peritumoral infiltration, and presence of enlarged solid tubal mass adjacent to the uterus (p < 0.05). CONCLUSION The present study suggests that CT is useful in differentiating torsed from uncomplicated BCT. Although CT findings are not specific for some patients, detection of certain CT findings could increase the diagnostic accuracy.

Definition of compression ratio: difference between two commercial JPEG2000 program libraries

The objective was to demonstrate the difference in the definition of compression ratio between two popular commercial JPEG 2000 program libraries. An institutional review board approved this study and waived informed consent. Using each of two JPEG 2000 libraries (libraries A and B), 20 abdomen computed tomography images with 12-bit depth (from scanner 1) and 20 images with 16-bit depth (from scanner 2) were compressed to three different nominal compression ratios: 10:1, 15:1, and 20:1. Achieved compression ratios (the original image file size to the compressed size) were compared with the nominal compression ratios using one-sample t-test tests. At each nominal compression level, the achieved compression ratios for scanner 1 images compressed using library A were approximately 1.33-fold greater than the nominal compression ratio (p < 0.0001), while the achieved compression ratios for the remaining three scanner-library combinations (scanner 1-library B, scanner 2-library A, and scanner 2-library B) were approximately the same as the nominal compression ratio (p-value range, 0.22-0.93). The definition of compression ratio is different between commercial JPEG 2000 program libraries. The definition should be standardized to facilitate the adoption and communication of an acceptable compression level.

Percutaneous insertion of Zilver stent in malignant biliary obstruction

BackgroundWe evaluated the clinical efficacy and technical feasibility of the percutaneously inserted self-expandable nitinol stent (Zilver stent) for palliation of malignant biliary obstruction.MethodsSeventeen patients with malignant tumors involving the intra- or extrahepatic bile duct who presented with obstructive jaundice underwent percutaneous insertion of a self-expandable nitinol stent. We retrospectively reviewed the hospital records of patients and evaluated the technical feasibility on stent placement, complications, patient survival, and duration of stent patency.ResultsPercutaneous biliary stenting with 27 Zilver stents was performed in 17 patients with malignant biliary obstruction. Technical success was 95%. Malposition of the stent was encountered in one patient. Minor technical problems were encountered in two patients: the introducer tip was broken during stent insertion, so endoscopic removal was done. Mean follow-up period for the 17 patients was 182 days (range 29–485 days): nine patients died of progressive disease at a mean follow-up of 151 days (range 61–371days) after stent insertion and eight patients remained alive at the final follow-up of 216 days (range 29–485 days). The median survival period for all patients was 277 days. The stent occlusion rate was 26% and the mean patency period was 280 days. In five patients, seven stents were obstructed by tumor ingrowth and overgrowth. Stent patency rates were 100%, 100%, 75%, 61%, and 41% at 1, 2, 3, 6, and 12 months, respectively. A late complication, erosive bleeding of the hepatic artery by the stent, developed in one patient.ConclusionPercutaneous biliary stenting using the nitinol stent is technically feasible and safe and clinically efficacious treatment for malignant biliary obstruction, even with a minor technical problem during stent insertion.

Findings from CT, MRI, and PET/CT of a primary malignant melanoma arising in a spinal nerve root

Primary spinal malignant melanoma is an extremely rare condition. We here describe a case of a 71-year-old Asian female presenting with left upper extremity tingling sensation. Computed tomography (CT) showed a homogeneously enhanced mass occupying the left neural foramen at the C6-7 level. Magnetic resonance imaging revealed enhanced mass in intra- and extradural space compressing the spinal cord at this level. It also widened the neural foramen mimicking neurofibroma or schwannoma. Partial resection of the mass was performed. Pathologic diagnosis of the mass was malignant melanoma. Postoperative whole body positron emission tomography/CT scan demonstrated an intense 18F-FDG uptake at the residual mass site without abnormal uptake at other sites in the body.

Intussusception associated with Yersinia pseudotuberculosis infection

Intussusception associated with Yersinia pseudotuberculosis infection was developed in three boys; two of them had a history of drinking untreated water. All intussusceptions were localized at the ileocolic region, and all patients completely recovered with GastrografinR enema and supportive treatment without complication and operation.