Prediction of microvascular invasion of hepatocellular carcinoma: usefulness of peritumoral hypointensity seen on gadoxetate disodium-enhanced hepatobiliary phase images.

PURPOSE: 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). MATERIALS AND METHODS: This study was approved by the Institutional Review Board. In all, 104 HCC masses in 104 patients who had undergone EOB-MRI and liver surgery within 1 month after EOB-MRI were evaluated. Two radiologists independently recorded the presence of a peritumoral hypointensity on hepatobiliary phase. Interobserver agreement was assessed and consensus records were used. Tumor size was measured. A chi-square test and independent t-test were used for univariate analysis. Multiple logistic regression was performed to determine factors for predicting microvascular invasion. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of peritumoral hypointensity were calculated. RESULTS: Sixty HCCs had microvascular invasion and 44 did not. Interobserver agreement in determining peritumoral hypointensity was excellent (κ = 0.83). By univariate analysis, peritumoral hypointensity and tumor size were significant for predicting microvascular invasion of HCC. On multiple logistic regression analysis, only peritumoral hypointensity was significant in predicting microvascular invasion of HCC (P = 0.013). The sensitivity, specificity, PPV, and NPV of peritumoral hypointensity were 38.3%, 93.2%, 88.5%, and 52.6%, respectively. CONCLUSION: Peritumoral hypointensity on the hepatobiliary phase of EOB-MRI is not sensitive but has high specificity for predicting microvascular invasion of HCC.

Langerhans Cell Histiocytosis of the Clavicle in a 50-Year-Old Male: A Case Report.

Langerhans cell histiocytosis (LCH) is a rare condition that usually occurs in children and commonly affects the skeletal system. It is extremely rare in adults, especially in the clavicles. In this report, we describe a pathologically confirmed case of LCH in the clavicle of a 50-year-old male. We report various radiological findings, such as plain radiography, CT, MR, and PET-CT, along with a review of the literature.

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 (18)F-FDG uptake at the residual mass site without abnormal uptake at other sites in the body.

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.

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.

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.

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 that's 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.

Primary extraskeletal mesenchymal chondrosarcoma arising from the pancreas.

We report here on a case of primary extraskeletal mesenchymal chondrosarcoma that arose from the pancreas. A 41-year-old man was evaluated by CT to find the cause of his abdominal pain. The CT scans showed a heterogeneously enhancing necrotic mass with numerous areas of coarse calcification, and this was located in the left side of the retroperitoneal space and involved the body and tail of the pancreas. Portal venography via the celiac axis also showed invasion of the splenic vein. Following excision of the mass, it was pathologically confirmed to be primary extraskeletal mesenchymal chondrosarcoma that arose from the pancreas.

CT of nasal-type T/NK cell lymphoma in the lung.

Nasal-type T-cell/natural killer cell lymphoma is a new distinctive clinicopathologic entity with a characteristic immunophenotypic expression of CD56. Most cases show a predilection for the nasopharyngeal region and are referred to as nasal T/NK-cell lymphoma. Few cases occur in areas other than the nose. To the best of our knowledge, nasal type T/NK cell lymphoma with isolated lung involvement has not been reported. We illustrate here the CT findings of this rare tumor occurring primarily in the lung.

Low-grade fibromyxoid sarcoma: CT, sonography, and MR findings in 3 cases.

Low-grade fibromyxoid sarcoma (LGFMS) is a distinctive variant of fibrosarcoma characterized by deceptively bland histologic features and a paradoxically aggressive clinical course. The radiologic finding of this uncommon tumor has not been described to date. In this report, 3 cases of LGFMS occurring in axilla, chest wall, and pleura are presented with CT, MRI, and sonographic findings.

Neurolymphomatosis of Brachial Plexus in Patients with Non-Hodgkin's Lymphoma.

Neurolymphomatosis (NL) is a rare clinical disease where neoplastic cells invade the cranial nerves and peripheral nerve roots, plexus, or other nerves in patients with hematologic malignancy. Most NL cases are caused by B-cell non-Hodgkin's lymphoma (NHL). Diagnosis can be made by imaging with positron emission tomography (PET) and magnetic resonance imaging (MRI). We experienced two cases of NL involving the brachial plexus in patients with NHL. One patient, who had NHL with central nervous system (CNS) involvement, experienced complete remission after 8 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy but relapsed into NL of the brachial plexus 5 months later. The other patient, who suffered from primary central nervous system lymphoma (PCNSL), had been undergoing chemoradiotherapy but progressed to NL of the brachial plexus.

Mesothelial cyst of the round ligament mimicking a metastasis: a case report.

A mesothelial cyst of the round ligament is a rare cause of an inguinal mass. Clinically, it is frequently misdiagnosed as one of commoner diseases such as an inguinal hernia, femoral hernia, lipoma, and lymphadenopathy upon physical examination. Some previous reports elaborated the sonographic features of a mesothelial cyst of the round ligament. However, to our knowledge, few reports have described the CT features of a mesothelial cyst. We illustrated here the sonographic and multidetector CT features of a case of a mesothelial cyst of the round ligament that presented as an inguinal palpable mass and mimicked a metastasis in a patient with a Sertoli-Leydig cell tumor of the ovary.

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.

An ROC study of chest radiographs: 2K Versus 4K high-resolution soft-copy images.

Computed radiography of chest with a 4K image array was recently introduced. We performed a multiobserver study to compare the diagnostic accuracy of 2K (standard) and 4K (high quality) chest radiographs displayed on a 5-mega-pixel monitor (2K monitor). One hundred cases of posteroanterior chest radiographs (a total of 200 images) were selected by two chest radiologists. Those radiographs included pneumothorax (n = 14), nodules (n = 15), interstitial disease (n = 10), or neither abnormality (n = 61). These were interpreted by four radiologists in two separate sessions. They recorded their confidence scale for the presence or absence of abnormality. Diagnostic accuracy was determined by receiver operating characteristic (ROC) analysis for each observer. ROC analysis showed no statistically significant difference between the 2K and 4K modes for the detection of any of the different abnormalities by individual readers. Our preliminary study suggests that 2K mode would be sufficient for the detection of abnormality on chest radiograph and there is no considerable validity to incline toward the 4K mode in current picture archiving and communication system environment using 2K monitor. However, we think that additional investigation using more subtle parenchymal or rib lesion should be followed.