Prognostic Value of Combined CT Angiography and Myocardial Perfusion Imaging versus Invasive Coronary Angiography and Nuclear Stress Perfusion Imaging in the Prediction of Major Adverse Cardiovascular Events: The CORE320 Multicenter Study.

Purpose To compare the prognostic importance (time to major adverse cardiovascular event [MACE]) of combined computed tomography (CT) angiography and CT myocardial stress perfusion imaging with that of combined invasive coronary angiography (ICA) and stress single photon emission CT myocardial perfusion imaging. Materials and Methods This study was approved by all institutional review boards, and written informed consent was obtained. Between November 2009 and July 2011, 381 participants clinically referred for ICA and aged 45-85 years were enrolled in the Combined Noninvasive Coronary Angiography and Myocardial Perfusion Imaging Using 320-Detector Row Computed Tomography (CORE320) prospective multicenter diagnostic study. All images were analyzed in blinded independent core laboratories, and a panel of physicians adjudicated all adverse events. MACE was defined as revascularization (>30 days after index ICA), myocardial infarction, or cardiac death; hospitalization for chest pain or congestive heart failure; or arrhythmia. Late MACE was defined similarly, except for patients who underwent revascularization within the first 182 days after ICA, who were excluded. Comparisons of 2-year survival (time to MACE) used standard Kaplan-Meier curves and restricted mean survival times bootstrapped with 2000 replicates. Results An MACE (49 revascularizations, five myocardial infarctions, one cardiac death, nine hospitalizations for chest pain or congestive heart failure, and one arrhythmia) occurred in 51 of 379 patients (13.5%). The 2-year MACE-free rates for combined CT angiography and CT perfusion findings were 94% negative for coronary artery disease (CAD) versus 82% positive for CAD and were similar to combined ICA and single photon emission CT findings (93% negative for CAD vs 77% positive for CAD, P < .001 for both). Event-free rates for CT angiography and CT perfusion versus ICA and single photon emission CT for either positive or negative results were not significantly different for MACE or late MACE (P > .05 for all). The area under the receiver operating characteristic curve (AUC) for combined CT angiography and CT perfusion (AUC = 68; 95% confidence interval [CI]: 62, 75) was similar (P = .36) to that for combined ICA and single photon emission CT (AUC = 71; 95% CI: 65, 79) in the identification of MACE at 2-year follow-up. Conclusion Combined CT angiography and CT perfusion enables similar prediction of 2-year MACE, late MACE, and event-free survival similar to that enabled by ICA and single photon emission CT. © RSNA, 2017 Online supplemental material is available for this article.

Diagnostic Performance of Transluminal Attenuation Gradient and Noninvasive Fractional Flow Reserve Derived from 320-Detector Row CT Angiography to Diagnose Hemodynamically Significant Coronary Stenosis: An NXT Substudy.

PURPOSE: To compare the diagnostic performance of 320-detector row computed tomography (CT) coronary angiography-derived computed fractional flow reserve (FFR; FFRCT), transluminal attenuation gradient (TAG; TAG320), and CT coronary angiography alone to diagnose hemodynamically significant stenosis as determined by invasive FFR. MATERIALS AND METHODS: This substudy of the prospective NXT study (no. NCT01757678) was approved by each participating institution's review board, and informed consent was obtained from all participants. Fifty-one consecutive patients who underwent 320-detector row CT coronary angiographic examination and invasive coronary angiography with FFR measurement were included. Independent core laboratories determined coronary artery disease severity by using CT coronary angiography, TAG320, FFRCT, and FFR. TAG320 is defined as the linear regression coefficient between luminal attenuation and axial distance from the coronary ostium. FFRCT was computed from CT coronary angiography data by using computational fluid dynamics technology. Diagnostic performance was evaluated and compared on a per-vessel basis by the area under the receiver operating characteristic (ROC) curve (AUC). RESULTS: Among 82 vessels, 24 lesions (29%) had ischemia by FFR (FFR ≤ 0.80). FFRCT exhibited a stronger correlation with invasive FFR compared with TAG320 (Spearman ρ, 0.78 vs 0.47, respectively). Overall per-vessel accuracy, sensitivity, specificity, and positive and negative predictive values for TAG320 (<15.37) were 78%, 58%, 86%, 64%, and 83%, respectively; and those of FFRCT were 83%, 92%, 79%, 65%, and 96%, respectively. ROC curve analysis showed a significantly larger AUC for FFRCT (0.93) compared with that for TAG320 (0.72; P = .003) and CT coronary angiography alone (0.68; P = .008). CONCLUSION: FFRCT computed from 320-detector row CT coronary angiography provides better diagnostic performance for the diagnosis of hemodynamically significant coronary stenoses compared with CT coronary angiography and TAG320.

Radiation-Dose-Lowering Effects of Landiolol Hydrochloride in Coronary Angiography Using Computed Tomography (DELIGHT)　- A Prospective Multicenter Study.

BACKGROUND: Controlling and decreasing the heart rate (HR) of patients during coronary computed tomography angiography (CCTA) is necessary to reduce radiation exposure and improve image quality. This prospective multicenter study aimed to investigate whether HR control with landiolol hydrochloride is useful for reducing radiation exposure during CCTA. METHODS AND RESULTS: We investigated 219 patients with suspected ischemic heart disease whose pretest HRs were 50-80 beats/min. We measured the HR before and after administration of landiolol hydrochloride and compared the estimated exposure inferred from the HR before administration of landiolol hydrochloride with the actual dose. After administration of landiolol hydrochloride, the mean HR (59.9±6.4 beats/min) at the time of CCTA was significantly lower than before administration (69.3±7.3 beats/min; P<0.001); 80% of the patients had controlled HRs at ≤65 beats/min. HR and blood pressure of all the patients recovered after the scan. The mean radiation dose in all patients was approximately 50% derived from the inferred dose before use of landiolol hydrochloride (4.5±3.2 vs. 9.0±3.7 mSv; P<0.001). There were no adverse events during this study. CONCLUSIONS: The use of landiolol hydrochloride during CCTA was safe and resulted in approximately 50% decrease in radiation exposure dose, suggesting the clinical usefulness of this drug. (Circ J 2016; 80: 1225-1231).

CT Dose Reduction for Visceral Adipose Tissue Measurement: Effects of Model-Based and Adaptive Statistical Iterative Reconstructions and Filtered Back Projection.

OBJECTIVE: The objective of our study was to evaluate the effects of radiation dose reduction and the reconstruction algorithm used--filtered back projection (FBP), adaptive statistical iterative reconstruction (ASIR), or model-based iterative reconstruction (MBIR)--on the measurement of abdominal visceral fat using CT. SUBJECTS AND METHODS: Standard-dose and low-dose abdominal CT examinations were performed simultaneously with automatic exposure control in 59 patients; the noise index for a 5-mm slice thickness was 12 for routine-dose CT and 24 for low-dose CT. The routine-dose CT images were reconstructed using FBP (reference standard), and the low-dose CT images were reconstructed using FBP, ASIR (so-called hybrid iterative reconstruction [IR]), and MBIR (so-called pure IR). In the 236 image series obtained, the visceral fat area was measured. Data were analyzed by the Pearson correlation coefficient test and a Bland-Altman difference analysis. RESULTS: The radiation dose of the low-dose abdominal CT examinations was 73.0% (mean) lower than that of routine-dose CT examinations. Excellent correlations were observed between the visceral fat areas measured on the routine-dose FBP images and those measured on the low-dose FBP, low-dose ASIR, and low-dose MBIR images (r = 0.998, 0.998, and 0.998, respectively; p < 0.001). A Bland-Altman difference analysis revealed excellent agreements, with mean biases of -0.47, -0.41, and 0.18 cm(2) for the visceral fat area between the routine-dose FBP images and the low-dose FBP, low-dose ASIR, and low-dose MBIR images, respectively. CONCLUSION: A 73.0% reduction of the radiation dose would be possible in CT for the measurement of the abdominal visceral fat regardless of which reconstruction algorithm is used (i.e., FBP, hybrid IR, or pure IR).

Non-invasive computed fractional flow reserve from computed tomography (CT) for diagnosing coronary artery disease ­ Japanese results from NXT trial (Analysis of Coronary Blood Flow Using CT Angiography: Next Steps).

BACKGROUND: Recently, a non-invasive method using computational fluid dynamics to calculate vessel-specific fractional flow reserve (FFRCT) from routinely acquired coronary computed tomography angiography (CTA) was described. The Analysis of Coronary Blood Flow Using CT Angiography: Next Steps (NXT) trial, which was a prospective, multicenter trial including 254 patients with suspected coronary artery disease, noted high diagnostic performance of FFRCT compared with invasive FFR. The aim of this post-hoc analysis was to assess the diagnostic performance of non-invasive FFRCT vs. standard stenosis quantification on coronary CTA in the Japanese subset of the NXT trial. METHODS AND RESULTS: A total of 57 Japanese participants were included from Okayama University (n=36), Kyoto University (n=17), and Keio University (n=4) Hospitals. Per-patient diagnostic accuracy of FFRCT(74%; 95% confidence interval [CI]: 60-85%) was higher than for coronary CTA (47%; 95% CI: 34-61%, P<0.001) arising from improved specificity (63% vs. 27%, P<0.001). FFRCT correctly reclassified 53% of patients and 63% of vessels with coronary CTA false positives as true negatives. When patients with Agatston score >1,000 were excluded, per-patient accuracy of FFRCT was 83% with a high specificity of 76%, similar to the overall NXT trial findings. CONCLUSIONS: FFRCT has high diagnostic performance compared with invasive FFR in the Japanese subset of patients in the NXT trial.

Computed tomography angiography and perfusion to assess coronary artery stenosis causing perfusion defects by single photon emission computed tomography: the CORE320 study.

AIMS: To evaluate the diagnostic power of integrating the results of computed tomography angiography (CTA) and CT myocardial perfusion (CTP) to identify coronary artery disease (CAD) defined as a flow limiting coronary artery stenosis causing a perfusion defect by single photon emission computed tomography (SPECT). METHODS AND RESULTS: We conducted a multicentre study to evaluate the accuracy of integrated CTA-CTP for the identification of patients with flow-limiting CAD defined by ≥50% stenosis by invasive coronary angiography (ICA) with a corresponding perfusion deficit on stress single photon emission computed tomography (SPECT/MPI). Sixteen centres enroled 381 patients who underwent combined CTA-CTP and SPECT/MPI prior to conventional coronary angiography. All four image modalities were analysed in blinded independent core laboratories. The prevalence of obstructive CAD defined by combined ICA-SPECT/MPI and ICA alone was 38 and 59%, respectively. The patient-based diagnostic accuracy defined by the area under the receiver operating characteristic curve (AUC) of integrated CTA-CTP for detecting or excluding flow-limiting CAD was 0.87 [95% confidence interval (CI): 0.84-0.91]. In patients without prior myocardial infarction, the AUC was 0.90 (95% CI: 0.87-0.94) and in patients without prior CAD the AUC for combined CTA-CTP was 0.93 (95% CI: 0.89-0.97). For the combination of a CTA stenosis ≥50% stenosis and a CTP perfusion deficit, the sensitivity, specificity, positive predictive, and negative predicative values (95% CI) were 80% (72-86), 74% (68-80), 65% (58-72), and 86% (80-90), respectively. For flow-limiting disease defined by ICA-SPECT/MPI, the accuracy of CTA was significantly increased by the addition of CTP at both the patient and vessel levels. CONCLUSIONS: The combination of CTA and perfusion correctly identifies patients with flow limiting CAD defined as ≥50 stenosis by ICA causing a perfusion defect by SPECT/MPI.

OATP1B3 expression is strongly associated with Wnt/ß-catenin signalling and represents the transporter of gadoxetic acid in hepatocellular carcinoma.

BACKGROUND & AIMS: In the current era of emerging molecular targeted drugs, it is necessary to identify before treatment the specific subclass to which a tumour belongs. Gadoxetic acid is a liver-specific contrast agent that is preferentially taken up by hepatocytes. Therefore, gadoxetic acid-enhanced magnetic resonance imaging (EOB-MRI) should provide precise molecular information about hepatocellular carcinomas (HCCs). The aim of this study was to investigate the transporters of gadoxetic acid in HCC comprehensively and to analyse the molecular regulatory mechanism of such transporters. METHODS: Expression levels of transporters, transcriptional factors and Wnt target genes in clinical samples were examined by quantitative real-time reverse transcription polymerase chain reaction and immunohistochemistry. LiCl treatment of the HCC cell line KYN-2 was conducted in vitro to assess the effects of Wnt signalling activity. RESULTS: Comprehensive analyses of transporter mRNAs and protein expressions revealed that the organic anion transporting polypeptide 1B3 (OATP1B3) had the strongest correlation with tumour enhancement in hepatobiliary-phase images of EOB-MRI. Association analysis with OATP1B3 expression revealed significant correlation with the expression of Wnt/ß-catenin target genes. Further, LiCl treatment induced OATP1B3 mRNA expression in KYN-2 cells, indicating a strong association between OATP1B3 expression and Wnt/ß-catenin signalling. The sensitivity and specificity to predict Wnt/ß-catenin-activated HCC using tumour enhancement in EOB-MRI were 78.9% and 81.7%, respectively. CONCLUSIONS: OATP1B3 was confirmed as the most important transporter mediating HCC enhancement in EOB-MRI. OATP1B3 expression showed a strong association with the expression of Wnt/ß-catenin target genes, therefore, OATP1B3-upregulated HCC likely represents a specific subclass of Wnt/ß-catenin-activated HCC.

Renal cell carcinoma in patients with acquired cystic disease of the kidney: assessment using a combination of T2-weighted, diffusion-weighted, and chemical-shift MRI without the use of contrast material.

PURPOSE: To evaluate the MRI findings of renal cell carcinoma (RCC), including findings on diffusion-weighted images (DWIs) and chemical shift images (CSIs), in patients with acquired cystic disease of the kidney (ACDK) in relation to the histopathologic findings. MATERIALS AND METHODS: Two radiologists retrospectively reviewed the MRI findings of 10 RCCs in seven consecutive patients with ACDK. They evaluated the signal intensities (SIs) and signal homogeneity of the lesions on T2-weighted images, DWIs, and T1-weighted images. Thereafter, they evaluated the cytoplasmic fat in the lesions by CSIs. After image analyses, the MRI findings were correlated with the histopathologic findings. RESULTS: The RCCs tended to show heterogeneous high SIs on T2-weighted images and DWIs. The high SIs on DWIs were mainly attributable to the viable parts, and the heterogeneity was due to the various SIs arising from the intratumoral degenerative components. Unlike the reported findings for hemorrhagic cysts, the RCCs did not show homogeneous high SIs or fluid-iron levels on T1-weighted images. The four lesions, in which the presence of cytoplasmic fat was suggested on CSIs, were clear cell RCCs. CONCLUSION: The MRI findings, including findings on DWIs and CSIs, well reflected the histopathologic findings of RCC in patients with ACDK.

Surgical anatomy imaging associated with cervical cancer treatment: A cadaveric study.

The objectives of this study were to visualize the surgical anatomical structures in the female pelvis by computed tomography and to investigate the components of the parametrium for anatomical education, radiological diagnosis, and surgical simulation. We surgically dissected fresh female cadavers maintained in precise surgical anatomic positions and examined the anatomical structures using experimental fine cell detector multislice computed tomography (FDCT) with a slice thickness of 0.3125 mm. In addition, we established a three-dimensional (3D) reconstruction model for precise observation of the surgical anatomy using Materialise's Interactive Medical Image Control System (Mimics). We evaluated two-dimensional (2D) images of the surgical anatomical structures in combination with the 3D reconstruction model. The 3D model was reconstructed from 430 serial axial pelvic CT images of a cadaver. The cardinal ligament, uterosacral ligament, paravesical space, and pararectal space were visualized on the CT images obtained from the surgically dissected part. The parametrium components were clearly distinguished on the surgically dissected side. Based on the information from the dissected side, these components on the undissected side could be distinguished as well. We recognized the parametrium components in the area extirpated during radical hysterectomy. The approach using cadavers, experimental FDCT, and 3D software provided excellent visualization of pelvic structures. High-quality images of surgical anatomical structures provide new insight regarding precise surgical anatomy in the female pelvis. The radiological information has practical usefulness for radiotherapeutic planning and surgical simulation.

Biliary findings assist in predicting enlargement of intraductal papillary mucinous neoplasms of the pancreas.

BACKGROUND & AIMS: There is controversy over the optimal management strategy for patients with branch-duct type intraductal papillary mucinous neoplasms of the pancreas (BD-IPMNs), precursors to pancreatic cancer. We aimed to identify factors associated with the presence of BD-IPMNs and changes in their diameter. METHODS: Two separate analyses were conducted in a cohort of patients who underwent magnetic resonance cholangiopancreatography (MRCP) in a single year (2006). MRCP findings and clinical outcomes of these patients were followed for a maximum of 6 years. We evaluated initial MRCP findings and demographics associated with the presence of BD-IPMNs at baseline and increase in BD-IPMN diameter over time. RESULTS: During the follow-up period, 154 patients developed BD-IPMN and 322 patients did not. Older age, diabetes mellitus, gallbladder adenomyomatosis, and absence of gallstones were associated with the presence of BD-IPMNs at baseline. Increases in diameter of BD-IPMNs were associated with 3 baseline factors: BD-IPMN diameter greater than 17 mm, gallbladder adenomyomatosis, and a common bile duct diameter less than 5.5 mm. Patients with BD-IPMNs could be stratified into 4 groups with varying risk for the enlargement of BD-IPMNs over time: those with 3 risk factors (hazard ratio [HR], 11.4; 95% confidence interval [CI], 3.4-37.8), 2 risk factors (HR, 4.7; 95% CI, 1.7-12.8), or 1 risk factor (HR, 3.1; 95% CI, 1.2-8.2) compared with those without risk factors. CONCLUSIONS: For patients with BD-IPMNs, careful follow-up evaluation is particularly important for those with BD-IPMN >17 mm in size, common bile duct diameter <5.5 mm, or gallbladder adenomyomatosis.

Tomosynthesis for the early detection of pulmonary emphysema: diagnostic performance compared with chest radiography, using multidetector computed tomography as reference.

OBJECTIVES: To compare the diagnostic performance of tomosynthesis with that of chest radiography for the detection of pulmonary emphysema, using multidetector computed tomography (MDCT) as reference. METHODS: Forty-eight patients with and 63 without pulmonary emphysema underwent chest MDCT, tomosynthesis and radiography on the same day. Two blinded radiologists independently evaluated the tomosynthesis images and radiographs for the presence of pulmonary emphysema. Axial and coronal MDCT images served as the reference standard and the percentage lung volume with attenuation values of -950 HU or lower (LAA-950) was evaluated to determine the extent of emphysema. Receiver-operating characteristic (ROC) analysis and generalised estimating equations model were used. RESULTS: ROC analysis revealed significantly better performance (P < 0.0001) of tomosynthesis than radiography for the detection of pulmonary emphysema. The average sensitivity, specificity, positive predictive value and negative predictive value of tomosynthesis were 0.875, 0.968, 0.955 and 0.910, respectively, whereas the values for radiography were 0.479, 0.913, 0.815 and 0.697, respectively. For both tomosynthesis and radiography, the sensitivity increased with increasing LAA-950. CONCLUSIONS: The diagnostic performance of tomosynthesis was significantly superior to that of radiography for the detection of pulmonary emphysema. In both tomosynthesis and radiography, the sensitivity was affected by the LAA-950. KEY POINTS: • Tomosynthesis showed significantly better diagnostic performance for pulmonary emphysema than radiography. • Interobserver agreement for tomosynthesis was significantly higher than that for radiography. • Sensitivity increased with increasing LAA -950 in both tomosynthesis and radiography. • Tomosynthesis imparts a similar radiation dose to two projection chest radiography. • Radiation dose and cost of tomosynthesis are lower than those of MDCT.

Factors affecting local progression after percutaneous cryoablation of lung tumors.

PURPOSE: To evaluate factors predicting local tumor progression after percutaneous cryoablation of lung tumors (PCLT). MATERIALS AND METHODS: Seventy-one consecutive patients with 210 tumors (11 primary and 199 metastatic pulmonary neoplasms; mean maximum diameter, 12.8 mm) were treated with 102 sessions of PCLT. Rates of local tumor progression and technique effectiveness were estimated by Kaplan-Meier method. Multiple variables were evaluated with the log-rank test, followed by uni- and multivariate multilevel analyses to identify independent risk factors, and hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated. All statistical tests were two-sided. RESULTS: Median follow-up period was 454 days (range, 79-2,467 d). Local tumor progression occurred in 50 tumors (23.8%). One-, 2-, and 3-year local progression-free rates were 80.4%, 69.0%, and 67.7%, respectively, and technique effectiveness rates were 91.4%, 83.0%, and 83.0%, respectively. Existence of a thick vessel (diameter≥3 mm) no more than 3 mm from the edge of the tumor was assessed as an independent factor (HR, 3.84; 95% CI, 1.59-9.30; P = .003) associated with local progression by multivariate analysis. CONCLUSIONS: Presence of a vessel at least 3 mm in diameter close to the tumor represents an independent risk factor for local progression after PCLT.

Three-dimensional imaging and mapping of the right and left phrenic nerves: relevance to interventional cardiovascular therapy.

AIMS: Phrenic nerves (PNs) can be damaged during interventional cardiovascular therapy because of the nerves' proximity to the heart. This study aimed to analyse the anatomy of the PN by performing three-dimensional (3-D) imaging and pace mapping. METHODS AND RESULTS: Forty consecutive patients with atrial fibrillation referred for catheter ablation were enrolled in this study and underwent preoperative cardiovascular computed tomography (CT). In 10 patients with sinus rhythm during tomography, 3-D images of the right and left pericardiophrenic bundles (PBs), consisting of the ipsilateral PN and accompanying vessels, were reconstructed from the CT data. During the electrophysiological study, PN pace mapping was performed from both atria. The course of the PBs generated by CT imaging and the PN pace map generated by the 3-D mapping system were compared. By electrical pacing, the PNs were captured in 40 individuals (100%) from the superior vena cava and the right atrium, and in 17 patients (43%) from the left atrial appendage. Clear 3-D images of PBs were reconstructed in all cases in which CT-reconstruction was performed. The distance between the locations of the right PB generated by CT imaging and those of the right PN-capture sites in the right-sided heart on the mapping system was 8.7 ± 5.8 mm. CONCLUSIONS: The 3-D routes of the bilateral PNs passing near the heart were verified by pace mapping. The preoperatively reconstructed 3-D course of the PB succeeded in locating the PN, which may facilitate the comprehension of PN anatomy to avoid its injury during interventional cardiovascular therapy.

Whole-brain CT digital subtraction angiography of cerebral dural arteriovenous fistula using 320-detector row CT.

INTRODUCTION: The purpose of this study was to evaluate the usefulness of CT digital subtraction angiography (CTDSA) by using 320-detector row CT in the diagnosis and classification of cerebral dural arteriovenous fistula (dAVF) and comparing it with DSA as the standard reference. METHODS: A total of 29 CTDSA/DSA from 25 patients with dAVF were retrospectively evaluated by two neuroradiologists. The presence, Cognard classification, and feeding arteries of dAVFs on CTDSA were assessed according to DSA. RESULTS: DSA depicted 33 dAVFs in 28 cases. By consensus reading, CTDSA correctly detected 32 dAVFs in 27 cases and properly graded 31 lesions. The intermodality agreement for the presence and classification of dAVFs was excellent (kappa = 0.955 and 0.921, respectively). CTDSA detected 77 of 109 feeding arteries (70.6%) in 25 cases. The intermodality agreement for the feeding arteries was good (kappa = 0.713). CONCLUSION: Although CTDSA is limited in temporal and spatial resolution in comparison with DSA, it is an effective non-invasive tool for the detection and classification of dAVF.

Large renal arteriovenous fistula with left-sided inferior vena cava.

Idiopathic renal arteriovenous fistulas (RAVFs) are uncommon, and a left-sided inferior vena cava (IVC) is also rare. We report a large idiopathic RAVF in a 36-year-old woman who had progressive congestive heart failure. An abdominal computed tomographic scan revealed an enlarged IVC on the left side and a 5.0-×4.5-cm RAVF with a single communication between the left renal artery and vein. Transcatheter embolization was not performed because complete flow control by a balloon catheter could not be achieved. Because of the size of the RAVF and the left-sided position of the IVC, nephrectomy was performed.

Epithelioid angiomyolipoma of the kidney: radiological imaging.

OBJECTIVES: To review the imaging findings of renal epithelioid angiomyolipomas. METHODS: Eight patients treated at two institutions were pathologically diagnosed as having epithelioid angiomyolipoma. All of them underwent computed tomography, and four underwent magnetic resonance imaging. The tumor size, existence of fat, heterogeneity, computed tomography attenuation, degree of enhancement, enhancement pattern and magnetic resonance imaging signal intensity were evaluated. RESULTS: Intratumoral fat was not detected in any of the cases. On unenhanced computed tomography, the intratumoral attenuation was hyperattenuating in six of the seven patients who were examined using this modality. On T2-weighted images, the signal intensity of the solid component, cyst wall or septum was low in three of the four cases. Four of the eight cases were heterogeneous solid-type accompanied by hemorrhage, necrosis or hyalinization. One homogeneous solid-type lesion was large in size and was pathologically accompanied by neither hemorrhage nor necrosis. All three multilocular cystic types were pathologically accompanied by massive hemorrhage in the cystic component. One was accompanied by spontaneous perirenal hematoma. CONCLUSIONS: The radiological appearance of most epithelioid angiomyolipomas has a tendency to be hyperattenuating on unenhanced computed tomography images, with low intensities on T2-weighted images. They can be heterogeneously solid, homogeneously solid or a multilocular cystic lesion with massive hemorrhage.

Three-dimensional demonstration of the lymphatic system in the lower extremities with multi-detector-row computed tomography: a study in a cadaver model.

Sentinel lymph node biopsy (SLNB) has had a great impact on the staging and treatment of cancer. The purpose of this study was to study the lymphatic anatomy of the lower extremities by constructing three-dimensional images using multi-detector-row computed tomography (MDCT). To select appropriate contrast media for MDCT lymphatic imaging in a cadaver, we tested four kinds of contrast media by injecting them into fresh swine kidneys. After the suitable contrast medium was selected, 10 lower extremities from 5 fresh cadavers were studied. After injection of the contrast medium, each lower extremity was scanned with high-spatial-resolution MDCT. The zinc oxide mixture was found to be the most appropriate contrast formula for MDCT imaging of cadaver lymphatics in terms of CT value and no extravasation. The high-resolution MDCT imaging revealed two different superficial lymphatic pathways in the legs. One lymphatic pathway accompanying the great saphenous vein had a constant course and was connected to the superficial inguinal lymph nodes. However, another pathway, along the small saphenous vein, was variable. Some of the deep lymphatic vessels bypassed the inguinal lymph nodes. Using a new protocol, we were able to construct three-dimensional images of the lower extremity lymphatics in a cadaver model. MDCT imaging provided novel information about two different superficial lymphatic pathways in the lower extremities.

Radiological findings of primary localized amyloidosis of the ureter.

Localized amyloidosis is a rare condition, especially that involving the ureter. Because of its rarity and the difficulty in differentiating this condition from urothelial carcinoma by intravenous urography and computed tomography, nephroureterectomy has often been performed unnecessarily for this disease. The authors encountered two cases of this disease, both of which showed a negative urine cytology, no obvious mass effect, and a hypointensity on T2-weighted imaging. Because these findings are very rare in urothelial carcinoma, ureteroscopy-guided biopsy was performed, which yielded the diagnosis of amyloidosis. The patients were then treated and followed up at our institute. Primary localized amyloidosis of the ureter should be considered when evaluating ureteric lesions visualized as hypointensities on T2-weighted images that do not show an obvious mass effect, which could help in the avoidance of unnecessary surgery.

Computed tomographic appearance of lung tumors treated with percutaneous cryoablation.

PURPOSE: To describe the computed tomographic (CT) appearance of lung tumors treated with cryoablation to establish a reliable reference profile. MATERIALS AND METHODS: CT images of 56 patients who underwent follow-up CT for at least 1 year for treatment with cryoablation of 79 tumors from 2003 to 2010 were retrospectively reviewed. Patients had a follow-up CT scan immediately after the procedure; 1 day, 1 week (two-phase dynamic CT), and 1 month later; and then at 3-month intervals. The appearance of ablation zones on CT images was classified into five patterns, and bidimensional diameters and other imaging features were evaluated. RESULTS: Seventy-eight percent of ablation zones (62 of 79) showed transformation similar to the following: a consolidation or nodular pattern was seen within the 1-week follow-up, involution and a "stripe" pattern was shown at 1 month or later, and zones later became indistinct. Eighty percent of cases of local progression (eight of 10) arose from the stripe pattern on follow-up CT 6 months or later, after the ablation zones showed a transformation opposite the aforementioned pattern. Ice balls could not always be visualized exactly because of dense peritumoral hemorrhage. Internal and marginal enhancement of the ablation zone within the 3-month follow-up did not show a direct relationship with local progression. In total, cavitation and peritumoral ground-glass opacity were seen in 35% (n = 28) and 85% (n = 66) of ablation zones, respectively. CONCLUSIONS: The reference profile of CT appearance, which is mandatory for follow-up, has been established. No single indicator of complete ablation was proven throughout this study. Careful long-term follow-up with CT is indispensable.

Percutaneous cryoablation of lung tumors: feasibility and safety.

PURPOSE: To evaluate the safety and feasibility of cryoablation for lung tumors as well as the incidence of, and risk factors for, complications. MATERIALS AND METHODS: This study included 193 cryoablation sessions for 396 lung tumors in 117 consecutive patients. Univariate and multivariate analyses were performed to assess risk factors for common complications. Changes in laboratory values were analyzed the day after cryoablation. RESULTS: Pneumothorax, pleural effusion, and hemoptysis occurred after 119 (61.7%), 136 (70.5%), and 71 (36.8%) sessions, respectively. Phrenic nerve palsy, frostbite, and empyema occurred after one session each (0.52%). Proximal tumor implantation was observed in one of 471 punctures (0.20%). Of 119 sessions with pneumothorax, 21 (17.6%) required chest tube insertion and two (1.7%) required pleurodesis. Delayed and recurrent pneumothorax occurred in 15 of 193 sessions each (7.8%). A greater number of cryoprobes was a significant (P = .001) predictor of pneumothorax. Male sex (P = .047) and no history of ipsilateral surgery (P = .012) were predictors for the need for chest tube insertion, and no history of ipsilateral surgery (P = .021) was a predictor for delayed/recurrent pneumothorax. Greater number of cryoprobes (P = .001) and no history of ipsilateral surgery (P = .004) were predictors for pleural effusion. Greater number of cryoprobes (P < .001) and younger age (P = .034) were predictors for hemoptysis. Mean changes in white blood cell count, platelet count, hemoglobin level, and C-reactive protein level were 2,418/µL ± 2,260 (P < .001), -2.0 × 10(4)/µL ± 3.2 (P < .001), -0.77 mg/dL ± 0.89 (P < .001), and 3.0 mg/dL ± 2.9 (P < .001), respectively. CONCLUSIONS: Percutaneous cryoablation could be performed minimally invasively with acceptable rates of complications.