Deep learning image reconstruction of diffusion-weighted imaging in evaluation of prostate cancer focusing on its clinical implications

Background

Image-based assessment of prostate cancer (PCa) is increasingly emphasized in the diagnostic workflow for selecting biopsy targets and possibly predicting clinically significant prostate cancer (csPCa). Assessment is based on Prostate Imaging-Reporting and Data System (PI-RADS) which is largely dependent on T2-weighted image (T2WI) and diffusion weighted image (DWI). This study aims to determine whether deep learning reconstruction (DLR) can improve the image quality of DWI and affect the assessment of PI-RADS ≥4 in patients with PCa.

Methods

In this retrospective study, 3.0T post-biopsy prostate magnetic resonance imaging (MRI) of 70 patients with PCa in Korea University Ansan Hospital from November 2021 to July 2022 was reconstructed with and without using DLR. Four DWI image sets were made: (I) conventional DWI (CDWI): DWI with acceleration factor 2 and conventional parallel imaging reconstruction, (II) DL1: DWI with acceleration factor 2 using DLR, (III) DL2: DWI with acceleration factor 3 using DLR, and (IV) DL3: DWI with acceleration factor 3 and half average b-value using DLR. Apparent diffusion coefficient (ADC) value, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured by one reviewer, while two reviewers independently assessed overall image quality, noise, and lesion conspicuity using a four-point visual scoring system from each DWI image set. Two reviewers also performed PI-RADSv2.1 scoring on lesions suspected of malignancy.

Results

A total of 70 patients (mean age, 70.8±9.7 years) were analyzed. The image acquisition time was 4:46 min for CDWI and DL1, 3:40 min for DL2, and 2:00 min for DL3. DL1 and DL2 images resulted in better lesion conspicuity compared to CDWI images assessed by both readers (P<0.05). DLR resulted in a significant increase in SNR, from 38.4±14.7 in CDWI to 56.9±21.0 in DL1. CNR increased from 25.1±11.5 in CDWI to 43.1±17.8 in DL1 (P<0.001). PI-RADS v2.1 scoring for PCa lesions was more agreeable with the DL1 reconstruction method than with CDWI (κ value CDWI, DL1; 0.40, 0.61, respectively). A statistically significant number of lesions were upgraded from PI-RADS <4 in CDWI image to PI-RADS ≥4 in DL1 images for both readers (P<0.05). Most of the PI-RADS upgraded lesions were from higher than unfavorable intermediate-risk groups according to the 2023 National Comprehensive Cancer Network guidelines with statistically significant difference of marginal probability in DL1 and DL2 for both readers (P<0.05).

Conclusions

DLR in DWI for PCa can provide options for improving image quality with a significant impact on PI-RADS evaluation or about a 23% reduction in acquisition time without compromising image quality.

Effect of dipeptidyl peptidase IV inhibitors, thiazolidinedione, and sulfonylurea on osteoporosis in patients with type 2 diabetes: population-based cohort study

The population-based cohort study used the Korean National Health Insurance claims database to evaluate the effect of anti-diabetic drugs on osteoporosis. The use of DPP-IV inhibitors does not increase the risk of osteoporosis compared with the use of sulfonylureas in patients with type 2 diabetes mellitus, while a weak association was found between thiazolidinediones and increased risk of osteoporosis.

PURPOSE

The current study aimed to evaluate the effect of dipeptidyl peptidase IV inhibitors (DPP-IVi), thiazolidinedione (TZD), and sulfonylurea (SU) on osteoporosis in patients with type 2 diabetes.

METHODS

A population-based cohort study was conducted in the Republic of Korea using the Korean National Health Insurance claims database. Data from 2012 to 2017 for patients of 50-99 years of age who were prescribed DPP-IVi, TZD, or SU during 2013-2015 were extracted from the database. Based on pre-defined criteria, a total of 381,404 patients were analyzed after inverse probability of treatment weighting. The association between the study drugs and osteoporosis was estimated using Cox proportional hazards models. Data of 220,166 patients who were prescribed DPP-IVi, 18,630 who were prescribed TZD, and 142,608 patients who were prescribed SU were set.

RESULTS

In the multivariate-adjusted analysis, the hazard ratio (HR) of osteoporosis in the DPP-IVi group was not significantly different from that of the SU group (HR: 0.97; 95% confidence interval (CI) 0.94-1.00), whereas the HR of osteoporosis in the TZD group was higher (HR: 1.13; 95% CI 1.06-1.20). In the subgroup analysis, the HRs of osteoporosis were higher with pioglitazone (HR: 1.14; 95% CI 1.06-1.23) in the TZD group and with glibenclamides (HR: 1.39; 95% CI 1.09-1.77) in the SU group, whereas drugs with lower HR in the DPP-IVi group were saxagliptin (HR: 0.93; 95% CI 0.87-0.99) and sitagliptin (HR: 0.93; 95% CI 0.89-0.97).

CONCLUSION

DPP-IV inhibitors do not increase the risk of osteoporosis compared with sulfonylureas in patients with type 2 diabetes mellitus, while a weak association was found between thiazolidinediones and increased risk of osteoporosis.

Feasibility of computed tomography texture analysis of hepatic fibrosis using dual-energy spectral detector computed tomography

PURPOSE

To evaluate feasibility of computer tomography texture analysis (CTTA) at different energy level using dual-energy spectral detector CT for liver fibrosis.

MATERIALS AND METHODS

Eighty-seven patients who underwent a spectral CT examination and had a reference standard of liver fibrosis (histopathologic findings, n = 61, or clinical findings for normal, n = 26) were included. Mean gray-level intensity, mean number of positive pixels (MPP), entropy, skewness, and kurtosis using commercially available software (TexRAD) were compared at different energy levels. Optimal CTTA parameter cutoffs to diagnose liver fibrosis were evaluated. CTTA parameters at different energy levels correlated with liver fibrosis. The association of CTTA parameters with energy level was evaluated.

RESULTS

Mean gray-level intensity, skewness, kurtosis, and entropy showed significant differences between patients with and without clinically significant hepatic fibrosis (P < 0.05). Mean gray-level intensity at 50 keV was significantly positively correlated with liver fibrosis (ρ = 0.502, P < 0.001). To diagnose stages F2-F4, entropy and mean gray-level intensity at low keV level showed the largest area under the curve (AUC; 0.79 and 0.79). Estimated marginal means (EMMs) of mean gray-level intensity showed prominent differences at low energy levels.

CONCLUSION

CTTA parameters from different keV levels demonstrated meaningful accuracy for diagnosis of liver fibrosis or clinically significant hepatic fibrosis.

Radiogenomic Analysis of Breast Cancer by Using B-Mode and Vascular US and RNA Sequencing

Background Radiogenomic investigations for breast cancer provide an understanding of tumor heterogeneity and discover image phenotypes of genetic variation. However, there is little research on the correlations between US features of breast cancer and whole-transcriptome profiling. Purpose To explore US phenotypes reflecting genetic alteration relevant to breast cancer treatment and prognosis by comparing US images of tumor with their RNA sequencing results. Materials and Methods From January to October 2016, B-mode and vascular US images in 31 women (mean age, 49 years ± 9 [standard deviation]) with breast cancer were prospectively analyzed. B-mode features included size, shape, echo pattern, orientation, margin, and calcifications. Vascular features were evaluated by using microvascular US and contrast agent-enhanced US: vascular index, vessel morphologic features, distribution, penetrating vessels, enhancement degree, order, margin, internal homogeneity, and perfusion defect. RNA sequencing was conducted with total RNA obtained from a surgical specimen by using next-generation sequencing. US features were compared with gene expression profiles, and ingenuity pathway analysis was used to analyze gene networks, enriched functions, and canonical pathways associated with breast cancer. The P value for differential expression was extracted by using a parametric F test comparing nested linear models. Results Thirteen US features were associated with various patterns of 340 genes (P < .05). Nonparallel orientation at B-mode US was associated with upregulation of TFF1 (log twofold change [log2FC] = 4.0; P < .001), TFF3 (log2FC = 2.5; P < .001), AREG (log2FC = 2.6; P = .005), and AGR3 (log2FC = 2.6; P = .003). Complex vessel morphologic structure was associated with upregulation of FZD8 (log2FC = 2.0; P = .01) and downregulation of IGF1R (log2FC = -2.0; P = .006) and CRIPAK (log2FC = -2.4; P = .01). The top networks with regard to orientation or vessel morphologic structure were associated with cell cycle, death, and proliferation. Conclusion Compared with RNA sequencing, B-mode and vascular US features reflected genomic alterations associated with hormone receptor status, angiogenesis, or prognosis in breast cancer. © RSNA, 2020 Online supplemental material is available for this article.

A Prospective Study on the Value of Ultrasound Microflow Assessment to Distinguish Malignant from Benign Solid Breast Masses: Association between Ultrasound Parameters and Histologic Microvessel Densities

OBJECTIVE

To investigate the value of ultrasound (US) microflow assessment in distinguishing malignant from benign solid breast masses as well as the association between US parameters and histologic microvessel density (MVD).

MATERIALS AND METHODS

Ninety-eight breast masses (57 benign and 41 malignant) were examined using Superb Microvascular Imaging (SMI) and contrast-enhanced US (CEUS) before biopsy. Two radiologists evaluated the quantitative and qualitative vascular parameters on SMI (vascular index, morphology, distribution, and penetration) and CEUS (time-intensity curve analysis and enhancement characteristics). US parameters were compared between benign and malignant masses and the diagnostic performance was compared between SMI and CEUS. Subgroup analysis was performed according to lesion size. The effect of vascular parameters on downgrading Breast Imaging Reporting and Data System (BI-RADS) category 4A masses was evaluated. The association between histologic MVD and US parameters was analyzed.

RESULTS

Malignant masses were associated with a higher vascular index (15.1 ± 7.3 vs. 5.9 ± 5.6), complex vessel morphology (82.9% vs. 42.1%), central vascularity (95.1% vs. 59.6%), penetrating vessels (80.5% vs. 31.6%) on SMI (all, p < 0.001), as well as higher peak intensity (37.1 ± 25.7 vs. 17.0 ± 15.8, p < 0.001), slope (10.6 ± 11.2 vs. 3.9 ± 4.2, p = 0.001), area (1035.7 ± 726.9 vs. 458.2 ± 410.2, p < 0.001), hyperenhancement (95.1% vs. 70.2%, p = 0.005), centripetal enhancement (70.7% vs. 45.6%, p = 0.023), penetrating vessels (65.9% vs. 22.8%, p < 0.001), and perfusion defects (31.7% vs. 3.5%, p < 0.001) on CEUS (p ≤ 0.023). The areas under the receiver operating characteristic curve (AUCs) of SMI and CEUS were 0.853 and 0.841, respectively (p = 0.803). In 19 masses measuring < 10 mm, central vascularity on SMI was associated with malignancy (100% vs. 38.5%, p = 0.018). Considering all benign SMI parameters on the BI-RADS assessment, unnecessary biopsies could be avoided in 12 category 4A masses with improved AUCs (0.500 vs. 0.605, p < 0.001). US vascular parameters associated with malignancy showed higher MVD (p ≤ 0.016). MVD was higher in malignant masses than in benign masses, and malignant masses negative for estrogen receptor or positive for Ki67 had higher MVD (p < 0.05).

CONCLUSION

US microflow assessment using SMI and CEUS is valuable in distinguishing malignant from benign solid breast masses, and US vascular parameters are associated with histologic MVD.

Identifying different types of microorganisms with terahertz spectroscopy

Most microbial detection techniques require pretreatment, such as fluorescent labeling and cultivation processes. Here, we propose novel tools for classifying and identifying microorganisms such as molds, yeasts, and bacteria based on their intrinsic dielectric constants in the THz frequency range. We first measured the dielectric constant of films that consisted of a wide range of microbial species, and extracted the values for the individual microbes using the effective medium theory. The dielectric constant of the molds was 1.24-1.85, which was lower than that of bacteria ranging from 2.75-4.11. The yeasts exhibited particularly high dielectric constants reaching 5.63-5.97, which were even higher than that of water. These values were consistent with the results of low-density measurements in an aqueous environment using microfluidic metamaterials. In particular, a blue shift in the metamaterial resonance occurred for molds and bacteria, whereas the molds have higher contrast relative to bacteria in the aqueous environment. By contrast, the deposition of the yeasts induced a red shift because their dielectric constant was higher than that of water. Finally, we measured the dielectric constants of peptidoglycan and polysaccharides such as chitin, α-glucan, and β-glucans (with short and long branches), and confirmed that cell wall composition was the main cause of the observed differences in dielectric constants for different types of microorganisms.

Feasibility of using computed tomography texture analysis parameters as imaging biomarkers for predicting risk grade of gastrointestinal stromal tumors: comparison with visual inspection

PURPOSE

To evaluate the feasibility of using computed tomography texture analysis (CTTA) parameters for predicting malignant risk grade and mitosis index of gastrointestinal stromal tumors (GISTs), compared with visual inspection.

METHOD AND MATERIALS

CTTA was performed on portal phase CT images of 145 surgically confirmed GISTs (mean size: 42.9 ± 37.5 mm), using TexRAD software. Mean, standard deviation, entropy, mean of positive pixels (MPP), skewness, and kurtosis of CTTA parameters, on spatial scaling factor (SSF), 2-6 were compared by risk grade, mitosis rate, and the presence or absence of necrosis on visual inspection. CTTA parameters were correlated with risk grade. Diagnostic performance was evaluated with receiver operating characteristic curve analysis. Enhancement pattern, necrosis, heterogeneity, calcification, growth pattern, and mucosal ulceration were subjectively evaluated by two observers.

RESULTS

Three to four parameters at different scales were significantly different according to the risk grade, mitosis rate, and the presence or absence of necrosis (p < 0.041). MPP at fine or medium scale (r = - 0.547 to - 393) and kurtosis at coarse scale (r = 0.424-0.454) correlated significantly with risk grade (p < 0.001). HG-GIST was best differentiated from LG-GIST by MPP at SSF 2 (AUC, 0.782), and kurtosis at SSF 4 (AUC, 0.779) (all p < 0.001). CT features predictive of HG-GIST were density lower than or equal to that of the erector spinae muscles on enhanced images (OR 2.1; p = 0.037; AUC, 0.59), necrosis (OR, 6.1; p < 0.001; AUC, 0.70), heterogeneity (OR, 4.3; p < 0.001; AUC, 0.67), and mucosal ulceration (OR, 3.3; p = 0.002; AUC, 0.62).

CONCLUSION

Using TexRAD, MPP and kurtosis are feasible in predicting risk grade and mitosis index of GISTs. CTTA demonstrated meaningful accuracy in preoperative risk stratification of GISTs.

Enhanced sensitivity in THz plasmonic sensors with silver nanowires

We developed hybrid slot antenna structures for microbial sensing in the THz frequency range, where silver nanowires (AgNWs) were employed to increase the sensitivity. In order to fabricate the hybrid devices, we partially etched the AgNW in the slot antenna region, where we can expect the field enhancement effect at the AgNW tip. We measured the resonant-frequency shift observed upon the deposition of a polymer layer, and observed that the sensitivity increased upon the introduction of AgNWs, with an enhancement factor of more than four times (approximately six times in terms of figure-of-merit). The sensitivity increased with the AgNW density until saturation. In addition, we tested devices with PRD1 viruses, and obtained an enhancement factor of 3.4 for a slot antenna width of 3 μm. Furthermore, we performed finite-difference time-domain simulations, which confirmed the experimental results. The sensitivity enhancement factor decreased with the decrease of the slot width, consistent with the experimental findings. Two-dimensional mapping of the electric field confirmed the strong field localization and enhancement at the AgNW tips.

Clinical Value of Real-Time Ultrasonography-MRI Fusion Imaging for Second-Look Examination in Preoperative Breast Cancer Patients: Additional Lesion Detection and Treatment Planning

BACKGROUND

This study was conducted to evaluate the clinical effect of real-time magnetic resonance imaging (MRI)-navigated ultrasonography (US) for preoperative second-look examination in patients with breast cancer.

PATIENTS AND METHODS

Between October 2013 and February 2015, 232 patients with breast cancer underwent MRI for staging; second-look US was performed in 70 patients to evaluate additional lesions suspected to be disease detected using MRI. We retrospectively included 67 lesions in 55 patients. Lesions were classified as detected on conventional US (group 1), and not visible on conventional US, but detected on MRI-navigated US (group 2). The imaging features between groups 1 and 2 were compared using Student t, χ², or Fisher exact tests. We compared the detection rate and histopathology of additional lesions using a McNemar test.

RESULTS

Heterogeneous background echotexture (69.6% [16 of 23] vs. 34.1% [14 of 41]) and lesion isoechogenicity (65.2% [15 of 23] vs. 7.3% [3 of 41]) on US and middle or posterior lesion depth on MRI (78.3% [18 of 23] vs. 46.3% [19 of 41]) were more common in group 2 (P < .05). More lesions were detected using MRI-navigated US (64 of 67; 95.5%) than conventional US (41 of 67; 61.2%; P < .01). Using MRI-navigated US we found more high-risk or malignant lesions than conventional US (21 vs. 11; P < .01). The optimal treatment plan was determined for 9 of 16 (56.3%) patients by virtue of MRI-navigated US.

CONCLUSION

Real-time MRI-navigated US significantly improved the detection of additional high-risk or malignant lesions during second-look US in preoperative evaluation of patients with breast cancer and ultimately determined the optimal treatment plan.

An Innovative Ultrasound Technique for Evaluation of Tumor Vascularity in Breast Cancers: Superb Micro-Vascular Imaging

Tumor vascularity is an important indicator for differential diagnosis, tumor growth, and prognosis. Superb micro-vascular imaging (SMI) is an innovative ultrasound technique for vascular examination that uses a multidimensional filter to eliminate clutter and preserve extremely low-velocity flows. Theoretically, SMI could depict more vessels and more detailed vascular morphology, due to the increased sensitivity of slow blood flow. Here, we report the early experience of using SMI in 21 breast cancer patients. We evaluated tumor vascular features in breast cancer and compared SMI and conventional color or power Doppler imaging. SMI was superior to color or power Doppler imaging in detecting tumor vessels, the details of vessel morphology, and both peripheral and central vascular distribution. In conclusion, SMI is a promising ultrasound technique for evaluating microvascular information of breast cancers.

Primary Neuroendocrine Carcinoma of the Breast with Clinical Features of Inflammatory Breast Carcinoma: A Case Report and Literature Review

Primary neuroendocrine carcinoma of the breast (NECB) is a very rare type of invasive breast carcinoma. Most NECBs appear on breast imaging as solid masses of varied shapes and margins, and have worse clinical outcomes than does invasive ductal carcinoma, not otherwise specified. However, there have been no reports to date regarding NECB with features of inflammatory breast carcinoma. Here, we describe the clinical, radiol-ogic, and pathologic findings of the first reported case of primary NECB presenting as inflammatory breast carcinoma. The patient complained of diffuse right breast enlargement and erythema. Mammography identified severe breast edema and axillary lymphadenopathy. Ultrasound detected an irregular, angular, hypoechoic mass with dermal lymphatic dilatation. On magnetic resonance imaging, the mass had rim enhancement and the entire right breast showed heterogeneous enhancement with malignant kinetic features. Pathology identified the mass as a primary NECB with positive for synaptophysin, CD56, estrogen and progesterone receptors.

Hepatic differentiation of porcine embryonic stem cells for translational research of hepatocyte transplantation

Porcine embryonic stem cells (ES) are considered attractive preclinical research tools for human liver diseases. Although several studies previously reported generation of porcine ES, none of these studies has described hepatic differentiation from porcine ES. The aim of this study was to generate hepatocytes from porcine ES and analyze their characteristics. We optimized conditions for definitive endoderm induction and developed a 4-step hepatic differentiation protocol. A brief serum-free condition with activin A efficiently induced definitive endoderm differentiation from porcine ES. The porcine ES-derived hepatocyte-like cells highly expressed hepatic markers including albumin and α-fetoprotein, and displayed liver characteristics such as glycogen storage, lipid production, and low-density lipoprotein uptake. For the first time, we describe a highly efficient protocol for hepatic differentiation from porcine ES. Our findings provide valuable information for translational liver research using porcine models, including hepatic regeneration and transplant studies, drug screening, and toxicology.

Prediction of liver cirrhosis, using diagnostic imaging tools

Early diagnosis of liver cirrhosis is important. Ultrasound-guided liver biopsy is the gold standard for diagnosis of liver cirrhosis. However, its invasiveness and sampling bias limit the applicability of the method. Basic imaging for the diagnosis of liver cirrhosis has developed over the last few decades, enabling early detection of morphological changes of the liver by ultrasonography (US), computed tomography, and magnetic resonance imaging (MRI). They are also accurate diagnostic methods for advanced liver cirrhosis, for which early diagnosis is difficult. There are a number of ways to compensate for this difficulty, including texture analysis to more closely identify the homogeneity of hepatic parenchyma, elastography to measure the stiffness and elasticity of the liver, and perfusion studies to determine the blood flow volume, transit time, and velocity. Amongst these methods, elastography using US and MRI was found to be slightly easier, faster, and able to provide an accurate diagnosis. Early diagnosis of liver cirrhosis using MRI or US elastography is therefore a realistic alternative, but further research is still needed.

Renal excretion of water-soluble contrast media after enema in the neonatal period

BACKGROUND

When abdominal distention occurs or bowel obstruction is suspected in the neonatal period, a water-soluble contrast enema is helpful for diagnostic and therapeutic purposes. The water-soluble contrast medium is evacuated through the anus as well as excreted via the kidneys in some babies. This study was designed to evaluate the incidence of renal excretion after enemas using water-soluble contrast media and presume the causes.

METHODS

Contrast enemas using diluted water-soluble contrast media were performed in 23 patients under 2 months of age. After the enema, patients were followed with simple abdominal radiographs to assess the improvement in bowel distention, and we could also detect the presence of renal excretion of contrast media on the radiographs. Reviewing the medical records and imaging studies, including enemas and consecutive abdominal radiographs, we evaluated the incidence of renal excretion of water-soluble contrast media and counted the stay duration of contrast media in urinary tract, bladder, and colon.

RESULTS

Among 23 patients, 12 patients (52%) experienced the renal excretion of water-soluble contrast media. In these patients, stay-in-bladder durations of contrast media were 1-3 days and stay-in-colon durations of contrast media were 1-10 days, while stay-in-colon durations of contrast media were 1-3 days in the patients not showing renal excretion of contrast media. The Mann-Whitney test for stay-in-colon durations demonstrated the later evacuation of contrast media in the patients with renal excretion of contrast media (p = 0.07). The review of the medical records showed that 19 patients were finally diagnosed as intestinal diseases, including Hirschsprung's disease, meconium ileum, meconium plug syndrome, and small bowel atresia or stenosis. Fisher's exact test between the presence of urinary excretion and intestinal diseases indicated a statistically significant difference (p = 0.04).

CONCLUSION

The intestinal diseases causing bowel obstruction may increase the water-soluble contrast media's dwell time in the bowel and also increase urinary excretion.

Quality assurance in ultrasound screening for hepatocellular carcinoma using a standardized phantom and standard clinical images: a 3-year national investigation in Korea

OBJECTIVES

The purpose of this study was to investigate the quality of ultrasound (US) imaging for hepatocellular carcinoma screening.

METHODS

The investigation was performed at all medical institutes participating in the National Cancer Screening Program in Korea. For assessment of personnel, we inquired who was performing the US screenings. For phantom image evaluation, the dead zone, vertical and horizontal measurements, axial and lateral resolution, sensitivity, and gray scale/dynamic range were evaluated. For clinical image evaluation, US images of patients were evaluated in terms of the standard images, technical information, overall image quality, appropriateness of depth, foci, annotations, and the presence of any artifacts.

RESULTS

Failure rates for phantom and clinical image evaluations at general hospitals, smaller hospitals, and private clinics were 20.9%, 24.5%, 24.1% and 5.5%, and 14.8% and 9.5%, respectively. No statistically significant difference was observed in the failure rates for the phantom images among groups of different years of manufacture. For the clinical image evaluation, the results of radiologists were significantly better than those of other professional groups (P = .0001 and .0004 versus nonradiology physicians and nonphysicians, respectively). The failure rate was also higher when the storage format was analog versus digital (P < .001).

CONCLUSIONS

Approximately 20% of US scanners failed the phantom image evaluation. The year of scanner manufacture was not significantly associated with the results of the phantom image evaluation. The quality of the clinical images obtained by radiologists was the best.

The effectiveness of gadolinium MRI to improve target delineation for radiotherapy in hepatocellular carcinoma: a comparative study of rigid image registration techniques

To achieve consistent target delineation in radiotherapy for hepatocellular carcinoma (HCC), image registration between simulation CT and diagnostic MRI was explored. Twenty patients with advanced HCC were included. The median interval between MRI and CT was 11 days. CT was obtained with shallow free breathing and MRI at exhale phase. On each CT and MRI, the liver and the gross target volume (GTV) were drawn. A rigid image registration was taken according to point information of vascular bifurcation (Method[A]) and pixel information of volume of interest only including the periphery of the liver (Method[B]) and manually drawn liver (Method[C]). In nine cases with an indefinite GTV on CT, a virtual sphere was generated at the epicenter of the GTV. The GTV from CT (VGTV[CT]) and MRI (VGTV[MR]) and the expanded GTV from MRI (V+GTV[MR]) considering geometrical registration error were defined. The underestimation (uncovered V[CT] by V[MR]) and the overestimation (excessive V[MR] by V[CT]) were calculated. Through a paired T-test, the difference between image registration techniques was analyzed. For method[A], the underestimation rates of VGTV[MR] and V+GTV[MR] were 16.4 ± 8.9% and 3.2 ± 3.7%, and the overestimation rates were 16.6 ± 8.7% and 28.4 ± 10.3%, respectively. For VGTV[MR] and V+GTV[MR], the underestimation rates and overestimation rates of method[A] were better than method[C]. The underestimation rates and overestimation rates of the VGTV[MR] were better in method[B] than method[C]. By image registration and additional margin, about 97% of HCC could be covered. Method[A] or method[B] could be recommended according to physician preference.

Functional magnetic resonance cholangiography with Gd-EOB-DTPA: a study in healthy volunteers

PURPOSE

To describe the patterns of bile distribution in the biliary tree, duodenum, jejunum, and stomach, and to determine the gallbladder ejection fraction (GBEF) by using functional magnetic resonance cholangiography (MRC) with gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA) in healthy volunteers.

MATERIALS AND METHODS

Forty subjects were included in this study. After conventional MRC, pre-fatty meal MRC (PRFM) was obtained at 30, 40, 50, and 60min after contrast agent injection. Then, post-fatty meal MRC (POFM) was obtained every 10min for 1h. We assessed the PRFM and POFM for opacification of contrast agent in the first- and second-order intrahepatic ducts (IHDs) and the common bile duct (CBD). Contrast agent opacification in the cystic duct was assessed, and the percentage volume of contrast agent filling in the gallbladder (GB) was calculated on PRFM. We calculated the GBEF and assessed the presence of contrast agent in the GB, duodenum, jejunum, and stomach.

RESULTS

Thirty-six (90%) subjects showed grade 3 CBD opacification (visible contrast and well-defined bile duct border) on 60-min PRFM. Thirty-four (85%) subjects showed grade 3 first-order IHD opacification on 60-min PRFM. All (100%) subjects showed cystic duct opacification of contrast agent, and the average percentage volume of contrast agent filling in the GB was 68.81%±16.84% on 60-min PRFM. The GBEF at 30-min POFM was 35.00%±18.26%. Ten (25%) subjects had no contrast agent in the stomach and small bowel on all PRFMs. Twelve (30%) subjects had contrast medium in the stomach on PRFM and/or POFM.

CONCLUSIONS

Functional MRC with Gd-EOB-DTPA can allow determining the distribution of bile in the biliary tree and small intestine, as well as the GBEF.

Infratentorial and intraparenchymal subependymoma in the cerebellum: case report

Subependymomas are rare benign tumors located in the ventricular system. Intraparenchymal subependymoma is extremely rare; only 6 cases have been reported, and all were located in the supratentorial region. We describe a case of infratentorial, intraparenchymal subependymoma in a 28-year-old man with intermittent headache. Imaging revealed a well-demarcated cystic and solid cerebellar mass near the fourth ventricle. The mass had a microcystic component and calcification without contrast enhancement. Complete surgical excision was performed, and histopathology confirmed a subependymoma.

Diagnosis of biliary stone disease: T1-weighted magnetic resonance cholangiography with Gd-EOB-DTPA versus T2-weighted magnetic resonance cholangiography

OBJECTIVE

We aimed to compare diagnostic performance of gadoxetic-acid-enhanced-T1-weighted-MR cholangiography (MRC) with that of conventional T2-weighted-MRC in diagnosing biliary stone disease.

MATERIALS AND METHODS

Ninety patients who underwent MRC for evaluation of biliary disease were included. Presence of stones in extrahepatic duct, gallbladder and intrahepatic duct, and presence of acute cholecystitis were evaluated. Sensitivity, specificity, and accuracy of biliary stone disease diagnosis in each biliary duct location according to each image sets were measured.

RESULTS

There was no significant difference in diagnostic performance between two sets of MRC in diagnosing biliary stone disease.

CONCLUSIONS

Diagnostic performance of T1-MRC with gadoxetic-acid in diagnosing biliary stone disease is comparable to that of T2-MRC.

Diagnosis of acute cholecystitis: value of contrast agent in the gallbladder and cystic duct on Gd-EOB-DTPA enhanced MR cholangiography

To evaluate value of %volume of contrast agent in gallbladder and contrast in cystic duct in diagnosis of acute cholecysititis with Gd-EOB-DTPA MRC obtained 60 min after contrast injection (T1-MRC60min). We included 16 acute cholecystitis (AC), 23 chronic cholecystitis (CC), and 40 healthy volunteers. Receiver operating characteristic analysis showed cutoff value of 30.5% as predictor of AC comparing with healthy volunteers (sensitivity 93.8%, specificity 100%, AUC 0.958) and cutoff of 0% as predictor of AC comparing CC (sensitivity 81.2%, specificity 82.6%, AUC 0.823). In AC absent or obliterated cystic duct on T1-MRC60min showed 81.3%, 100%, sensitivity and specificity, respectively. These can be helpful for diagnosis of AC.

Fluoroscopic guided fogarty embolectomy for an angio-seal embolism in the popliteal artery

The Angio-Seal is a widely used arterial closure device that helps achieve faster hemostasis and provide early ambulation to patients. However, it can cause various complications in clinical practice. We present the uncommon complication of popliteal artery occlusion following Angio-Seal deployment, and describe an effective interventional approach to its treatment. Because fluoroscopy-guided Fogarty embolectomy has the advantages of complete removal of the embolus without fragmentation, and clear visualization of the exact location of the embolus during the procedure, it is a suitable method for treating this complication.

Malignant fibrous histiocytoma arising from a hydronephrotic kidney: a case report and review of the literature

Primary malignant fibrous histiocytoma (MFH) is extremely rare, and MFH arising from a hydronephrotic kidney has not been reported. When MFH originates from a long-standing hydronephrotic kidney, the imaging findings can include nearly invisible renal parenchyma and atrophy of the ureter and renal artery, in addition to the findings attributable to the MFH, and the MFH with hydronephrosis may be confused with a cystic renal cell carcinoma.

Classification of Metastatic versus Non-Metastatic Axillary Nodes in Breast Cancer Patients: Value of Cortex-Hilum Area Ratio with Ultrasound

PURPOSE

To investigate the significance of the cortex-hilum (CH) area ratio and longitudinal-transverse (LT) axis ratio and the blood flow pattern for diagnosis of metastatic axillary lymph nodes by ultrasound in breast cancer patients.

METHODS

From October 2005 to July 2006, we prospectively evaluated axillary nodes with ultrasound in 205 consecutive patients who had category 4B, 4C or 5 breast lesions according to the Breast Imaging Reporting and Data System-Ultrasound (BI-RADS-Ultrasound®). Among the 205, there were 24 patients who had pathologic verification of breast cancer and axillary lymph node status. For a total of 80 axillary nodes we measured the areas of the cortex and hilum of lymph nodes and calculated the area ratio. We also measured the length of the longitudinal and transverse axis of the lymph nodes and calculated the length ratio. We evaluated the blood flow pattern on power Doppler imaging and classified each lymph node into a central or peripheral pattern. Diagnostic performance was analyzed according to positive criteria for lymph node metastasis (CH area ratio >2, LT axis ratio <2, peripheral type on power Doppler imaging).

RESULTS

The sensitivity of the CH area ratio was superior to that of the LT axis ratio (94.1% vs. 82.3%, p=0.031) and to that of the blood flow pattern (94.1% vs. 29.4%, p=0.009). For specificity, all three evaluating parameters had high values (89.1-95.6%) and no significant differences were found (p=0.121). The CH area ratio had a better positive predictive value than the LT axis ratio (94.1% vs. 80.0%, p=0.030) and power Doppler imaging (94.1% vs. 66.6%, p=0.028). For the negative predictive value, the CH area ratio was superior to the LT axis ratio (95.6% vs. 86.6%, p=0.035) and the blood flow pattern (95.6% vs. 63.0%, p=0.027).

CONCLUSION

We recommend the CH area ratio of an axillary lymph node on ultrasound as a quantitative indicator for the classification of lymph nodes. The CH area ratio can improve diagnostic performance when compared with the LT axis ratio or blood flow pattern.

Biliary reflux detection in anomalous union of the pancreatico-biliary duct patients

AIM: To demonstrate the imaging findings of biliopancreatic and pancreatico-biliary reflux in patients with anomalous union of the pancreatico-biliary duct (AUPBD) on gadoxetic acid-enhanced functional magnetic resonance cholangiography (fMRC).

METHODS: This study included six consecutive patients (two men and four women; mean age 47.5 years) with AUPBD. All subjects underwent endoscopic retrograde cholangiopancreatography (ERCP); one subject also underwent bile sampling of the common bile duct (CBD) to measure the amylase level because his gadoxetic acid-enhanced fMRC images showed evidence of pancreatico-biliary reflux of pancreatic secretions. Of the five patients with choledochal cysts, four underwent pylorus-preserving pancreaticoduodenectomy.

RESULTS: The five cases of choledochal cysts were classified as Todani classification I. In three of the six patients with AUPBD, injected contrast media reached the distal CBD and pancreatic duct on delay images, suggesting biliopancreatic reflux. In two of these six patients, a band-like filling defect was noted in the CBD on pre-fatty meal images, which decreased in size on delayed post-fatty meal images, suggesting pancreatico-biliary reflux of pancreatic secretions, and the bile sampled from the CBD in one patient had an amylase level of 113 000 IU/L. In one of the six patients with AUPBD, contrast media did not reach the distal CBD due to multiple CBD stones.

CONCLUSION: Gadoxetic acid-enhanced fMRC successfully demonstrated biliopancreatic reflux of bile and pancreatico-biliary reflux of pancreatic secretions in patients with AUPBD with and without choledochal cysts.

Establishing cutoff values for a quality assurance test using an ultrasound phantom in screening ultrasound examinations for hepatocellular carcinoma: an initial report of a nationwide survey in Korea

OBJECTIVES

The purpose of this study was to evaluate the results of ultrasound (US) device testing using a US phantom and to determine cutoff values for phantom quality assurance tests in US examinations for the screening of hepatocellular carcinoma in Korea.

METHODS

Ultrasound phantom images were acquired from the general hospitals in Korea that participated in the National Cancer Screening Program for hepatocellular carcinoma. Ultrasound images of the phantom were acquired with a 3.0- to 5.0-MHz convex transducer and evaluated in terms of the dead zone, vertical and horizontal measurement, axial and lateral resolution, sensitivity, and gray scale/dynamic range. Appropriate cutoff values were determined to guarantee minimal qualifications for the performance of the US scanners.

RESULTS

Three hundred fifty-seven US scanners were tested using the following cutoff values: less than 2 mm for the dead zone, 5% discrepancy in the vertical measurement, 7.5% discrepancy in the horizontal measurement, all 11 identifiable line targets for axial and lateral resolution, more than 14 cm for sensitivity, and more than 4 cylindrical structures for gray scale/dynamic range. With these criteria, 283 US scanners (79.3%) passed the tests. The most common cause of disqualification was the dynamic range/gray scale. No statistical difference was observed in the disqualification rate between 3 groups based on different years of manufacture.

CONCLUSIONS

Through this study, we have defined cutoff values for phantom images acquired with US scanners. These will be used in performing screening US examinations for hepatocellular carcinoma in Korea.

Scrotal swelling caused by acute necrotizing pancreatitis: CT diagnosis

Scrotal involvement is a rare complication of acute pancreatitis. It presents as scrotal swelling and skin color change, which mimics the presentations of testicular torsion, epididymitis, and testicular tumor. Its differential diagnosis is important because scrotal involvement of acute pancreatitis can be treated conservatively. Abdominopelvic CT provides a useful means of diagnosing this complication. Here, the authors present a case of acute pancreatitis extending to the left scrotum, mimicking a testicular tumor. A CT scan helped avoid unnecessary orchiectomy.

Single-session endovascular treatment for symptomatic lower extremity deep vein thrombosis: a feasibility study

BACKGROUND

The risk of complications and discomfort in patients who undergo prolonged infusion of a thrombolytic agent is significant when conventional catheter-directed thrombolysis is used to treat lower extremity deep vein thrombosis (DVT).

PURPOSE

To evaluate the feasibility and safety of single-session endovascular treatment for symptomatic lower extremity DVT.

MATERIAL AND METHODS

Single-session endovascular treatment for lower extremity DVT was performed on 29 limbs in 26 patients diagnosed with acute DVT in our institution. Nine patients were male and 17 female, with a mean age of 64 years (range 28-82 years). At 5-10 min after the locoregional injection of the thrombolytic agent (urokinase) via a 5-Fr catheter to soften the thrombus, aspiration thrombectomy was performed with a large-bore sheath. In patients with an underlying anatomical stenosis or obstruction, combined angioplasty with or without stent placement was performed immediately after the complete removal of the thrombus. We then evaluated the technical and clinical outcomes of the procedure, along with any complications or recurrences of DVT.

RESULTS

Technical success was achieved in 24 procedures (82.8%) of single-session endovascular treatment for lower extremity DVT, and clinical success was achieved in 22 (75.9%) of these single-session procedures. Additional catheter-directed thrombolysis procedures were performed on five limbs after repeated aspiration thrombectomies failed to completely remove thrombi in those limbs. Stenotic or occlusive lesions were revealed in 24 limbs and percutaneous angioplasty procedures with or without stent placement were performed in these cases. No major complications resulted from the procedure.

CONCLUSION

Single-session endovascular treatment is a feasible technique that provides acceptable technical and clinical success with excellent safety for treating symptomatic lower extremity DVT.

Diagnostic value of maximal-outer-diameter and maximal-mural-thickness in use of ultrasound for acute appendicitis in children

AIM: To evaluate the maximal-outer-diameter (MOD) and the maximal-mural-thickness (MMT) of the appendix in children with acute appendicitis and to determine their optimal cut-off values to diagnose acute appendicitis.

METHODS: In total, 164 appendixes from 160 children between 1 and 17 years old (84 males, 76 females; mean age, 7.38 years) were examined by high-resolution abdominal ultrasound for acute abdominal pain and the suspicion of acute appendicitis. We measured the MOD and the MMT at the thickest point of the appendix. Patients were categorized into two groups according to their medical records: patients who had surgery (surgical appendix group) and patients who did not have surgery (non-surgical appendix group). Data were analyzed by MedCalc v.9.3. The rank sum test (Mann-Whitney test) was used to evaluate the difference in the MOD and the MMT between the two groups. ROC curve analysis was used to determine the optimal cut-off value of the MOD and the MMT on diagnosis of acute appendicitis.

RESULTS: There were 121 appendixes (73.8%) in the non-surgical appendix group and 43 appendixes (26.2%) in the surgical appendix group. The median MOD differed significantly between the two groups (0.37 cm vs 0.76 cm, P < 0.0001), and the median MMT also differed (0.15 cm vs 0.33 cm, P < 0.0001). The optimal cut-off value of the MOD and the MMT for diagnosis of acute appendicitis in children was > 0.57 cm (sensitivity 95.4%, specificity 93.4%) and > 0.22 cm (sensitivity 90.7%, specificity 79.3%), respectively.

CONCLUSION: The MOD and the MMT are reliable criteria to diagnose acute appendicitis in children. An MOD > 0.57 cm and an MMT > 0.22 cm are the optimal criteria.

Immersion ultrasonography of excised nonpalpable breast lesion specimens after ultrasound-guided needle localization

Objective

Ultrasound-guided needle localization has been used prior to the surgical excision of nonpalpable breast lesions. The aim of the study was to assess the feasibility of the use of a saline immersion specimen ultrasound technique (immersion-US) to confirm the successful removal of breast lesions.

Materials and Methods

The devised immersion-US technique was used to examine the excised tissues of 72 ultrasound-guided needle localized breast lesions of 58 patients (34 benign lesions, 30 high-risk lesions and 8 malignant lesions). Freshly excised specimens were placed in a container filled with saline and one radiologist scanned the surgically excised specimens using a high-frequency linear transducer. We evaluated successful lesion removal and the qualities of the immersion-US images. Miss rates were determined by the use of postoperative ultrasound during follow-up.

Results

All 72 lesions were identified by the use of immersion-US and satisfactory or excellent quality images were obtained for most lesions (70/72, 97%). Five (7%) lesions were initially identified as incompletely excised, based on the immersion-US findings, and prompt re-excision was undertaken. Follow-up ultrasound examinations showed no residual mass in the surgical field in any patient.

Conclusion

The immersion-US technique was found straightforward and efficient to perform. Immersion-US was able to determine whether nonpalpable breast lesions had been successfully excised after ultrasound-guided needle localization.

A prospective comparison study for predicting circumferential resection margin between preoperative MRI and whole mount sections in mid-rectal cancer: significance of different scan planes

AIM

The aim of this study is to evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in the prediction of circumferential resection margin (CRM) and to determine whether each different MRI scan plane provides an accurate CRM assessment.

METHOD

Fifty-seven consecutive patients with mid-rectal cancer were enrolled prospectively. The CRM measurement from each MRI plane according to tumor location was compared with CRM measurement on whole-mount sections with the definition of threatened CRM as 2 mm in distance. The difference in performance among the sagittal, axial and oblique MR images was analyzed by using receiver operating characteristic (ROC) curves (A(z)).

RESULTS

For anterior tumors (n = 17), the A(z) of the sagittal, axial and oblique MR planes were 0.66, 0.83 and 0.79, respectively. For lateral tumors (n = 17), the A(z) of the sagittal, axial and oblique MR planes were 0.53, 0.66 and 0.78, respectively. For posterior tumors (n = 23), the A(z) of the sagittal, axial and oblique MR planes were 0.76, 0.82 and 0.97, respectively.

CONCLUSIONS

MRI provides an accurate prediction of preoperative CRM. There exist differences in diagnostic accuracy according to each different scan plane of MRI and tumor location within the rectum.

REMOVED: Assessment of Pulmonary Venous Variation by Multidetector row CT: Clinical Implication for Catheter Ablation Techniques for Atrial Fibrillation

This article has been removed, consistent with Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). The Publisher apologizes for any inconvenience this may cause.

Computed tomographic differences of pyogenic liver abscesses caused by Klebsiella pneumoniae and non-Klebsiella pneumoniae

OBJECTIVE

To investigate the distinctive computed tomographic(CT) features of pyogenic liver abscess (PLA) caused by Klebsiella pneumoniae (KLA).

METHODS

114 PLA patients (62 men, 52 women, age range 25-89 years, mean age 60.9 years) with positive yield of blood or pus cultures were divided into 2 groups; KLA group (n = 58) and non-KLA group (n = 56). We retrospectively reviewed the CT images. The independent-sample t-test, X2 test, or Fisher's exact test were used with SPSS for windows version 11.0.

RESULTS

Gas formation showed no significant difference between two groups (P = 0.284), but air-fluid pattern was found only in KLA group (P = 0.027). The rim on dynamic CT was showed less frequently in KLA group than non-KLA group (P < 0.001), and smooth and regular rim was more common in non-KLA group (P < 0.001). The septation and septal breakage were more common in KLA group (P < 0.001). The turquoise sign was found significantly more in KLA group (P < 0.001). The hairball sign was detected only in KLA group (P < 0.001). The cluster sign was less frequent in KLA group (P < 0.001).

CONCLUSION

KLA had a series of characteristic intra-abscess features; septal breakage, turquoise-like structure, hairball-like content, air-fluid level, and no enhanced rim. When turquoise/hairball sign or air-fluid level is present in abscess, KLA would be a probable diagnosis in the clinical field.

Production of mycelia and exo-biopolymer from molasses by Cordyceps sinensis 16 in submerged culture

The molecular weight of exo-biopolymer obtained from a submerged culture of Cordyceps sinensis 16 consisted of a main unit and a subunit of 126 and 68 kDa, respectively. The optimal medium for the production of mycelia and exo-biopolymer was determined to be molasses containing 2% sucrose, 0.9% yeast extract, 0.3% K2HPO4, and 0.4% CaCl2. Using optimized medium, maximum productions of mycelia and exo-biopolymer in shake-flask culture were 54.0 g/L and 28.4 g/L, respectively. This study suggests that large-scale production of mycelia and exo-biopolymer by C. sinensis 16 is possible in submerged culture.

Deep tracheal laceration after balloon dilation for benign tracheobronchial stenosis: case reports of two patients

We report two cases of deep tracheal laceration in female patients after balloon dilation for benign tracheobronchial stenosis. Immediate post-procedure bronchoscopy and CT including 3D reconstructions showed deep lacerations in the posterior tracheal wall. Clinically, the patients' dyspnoea subsided and there has been no recurrence during follow-up after balloon dilation. On the follow-up 3D-reconstructed CT scans obtained 2 months and 8 months following balloon dilation, respectively, the lacerations had healed completely and there was considerable improvement in lumen size.

Complete eversion and prolapse of bladder concurrent with primary adenocarcinoma

Complete eversion and prolapse of the urinary bladder is extremely rare. To the best of our knowledge, the imaging findings of complete bladder eversion have not been documented in the literature. Here, we report a case of complete eversion and prolapse of the urinary bladder demonstrated on MRI. Concurrent primary adenocarcinoma was found in the thickened wall of the everted urinary bladder.

Traumatic Axillary Artery Dissection with Radial Artery Embolism

This report describes a case of pathologically proven traumatic arterial dissection, presenting as complete occlusion of the axillary artery with radial artery embolism. Occlusion of the axillary artery by traumatic dissection mimicked transection and radial artery embolism mimicked congenital absence of the radial artery on the initial angiogram, but these were correctly diagnosed with the following sonogram.

PC-Based 3D Reconstruction of MR Angiography in Evaluation of Intracranial Aneurysms. The Value of Pre-Treatment Planning for Embolization and Post-Treatment Follow-up

SUMMARY

In this study, we present our experiences of personal computer-based 3D reconstructions of MRA for pre-treatment planning and post-treatment follow-up for cerebral aneurysms. Twentynine ruptured or unruptured intracranial aneurysm patients with 36 intracranial aneurysms, who underwent embolization and pretreatment and/or follow up 3D MRA were included in this study. All 29 patients were examined by DSA and MRA before (18 patients, 24 aneurysms) and/or after embolization (16 patients, 17 aneurysms). The MRA source images were transported to a personal computer in DICOM format for viewing, post-processing, and 3D reconstruction. DSA and PC based SSD 3D MRA equally well demonstrated most aneurysms before embolization (17 patients, 22 aneurysms). The depiction of aneurysm morphology, neck evaluation and branch vessel interpretation were much easier on 3D MRA, which has the ability to manipulate images in real time. When the vascular anatomy was complicated by another vascular system, the anterior or posterior circulations were separately reconstructed easily by using PC based reconstruction software. The 3D MRA also well demonstrated post-embolization recurrence or remnant aneurysmal cavities. In one giant aneurysm, the 3D MRA was unable to show the entire aneurysmal sac due to a blood flow saturation effect, but this was resolved by additional contrast material injection. PC-based 3D MRA proved to be a useful tool for the pretreatment planning of embolization procedures and for follow up after treatment in the case of cerebral aneurysms.

Fluid Infusion Technique for Ultrasound-Guided Percutaneous Nephrostomy

We describe a simple but useful technique for improving the visualization of the needle during ultrasound-guided percutaneous nephrostomy, especially suitable for obese patients.

Inflammatory myofibroblastic tumor of the stomach with peritoneal dissemination in a young adult: imaging findings

Inflammatory myofibroblastic tumors are lesions that most often affect young adults and children. These tumors have been found in numerous extrapulmonary sites but rarely in the stomach. It is unknown whether this process is reactive or neoplastic. They are infiltrative lesions and often extend through the gastric wall, sometimes reaching adjacent organs including the esophagus, duodenum, peritoneal cavity, spleen. pancreas, and liver. These features mimic malignancy on endoscopy and radiology. We report the ultrasound, color Doppler ultrasound, and helical computed tomographic findings of a gastric inflammatory myofibroblastic tumor with peritoneal dissemination in a young adult. To our knowledge, this is the first report of color Doppler ultrasound and helical computed tomographic findings of this rare disease entity.

Maple syrup urine disease encephalopathy: a follow-up study in the acute stage using diffusion-weighted MRI

Neonatal maple syrup urine disease (MSUD) is associated with diffuse oedema and characteristic MSUD oedema. We present a newborn infant with two coexisting different types of oedema. The myelinated white matter showed a marked decrease in the water apparent diffusion coefficient (ADC) compatible with cytotoxic oedema. The unmyelinated white matter showed an increase in ADC, consistent with vasogenic-interstitial oedema. On follow-up studies, the cytotoxic oedema showed improvement, but the vasogenic-interstitial oedema progressed into brain atrophy.

Moyamoya disease in a child with previous acute necrotizing encephalopathy

A previously healthy 24-day-old boy presented with a 2-day history of fever and had a convulsion on the day of admission. MRI showed abnormal signal in the thalami, caudate nuclei and central white matter. Acute necrotising encephalopathy was diagnosed, other causes having been excluded after biochemical and haematological analysis of blood, urine and CSF. He recovered, but with spastic quadriparesis. At the age of 28 months, he suffered sudden deterioration of consciousness and motor weakness of his right limbs. MRI was consistent with an acute cerebrovascular accident. Angiography showed bilateral middle cerebral artery stenosis or frank occlusion with numerous lenticulostriate collateral vessels consistent with moyamoya disease.

A case of non-Hodgkin's lymphoma in a patient with neurofibromatosis type 1

Neurofibromatosis type 1 is characterized by cutaneous neurofibromas and pigmented lesions of the skin called café au lait spots. Although neurofibromatosis type 1 represents a major risk factor for the development of malignancy, especially of nervous system tumors, malignant lymphoma rarely occurs in a patients with neurofibromatosis type 1. Recently, a 77-year-old woman with neurofibromatosis type 1 was diagnosed as non-Hodgkin's Lymphoma (diffuse large B cell). She had multiple café au lait spots, neurofibromas and right axillary lymph node enlargement. An abdominal CT scan demonstrated a left pelvic mass and para-aortic lymphadenopathy. Because non-Hodgkin's Lymphoma in a neurofibromatosis patient has never been reported in Korea, herein, we describe this case and include a review of the literature.

Nasopharyngeal carcinoma: posttreatment changes of imaging findings

OBJECTIVE

The purpose of this study was to determine the radiologic results of nasopharyngeal carcinoma (NPC) that showed complete responses on follow-up imaging studies after radiation therapy.

MATERIALS AND METHODS

This study is a retrospective review of 23 patients (18 male, 5 female, aged 15-71 years; mean age, 48.5 years) affected with NPC, from August 1995 to July 2000, who were examined with magnetic resonance imaging or computed tomography scan before and after either radical radiotherapy or chemoradiotherapy. The median follow-up was 24.7 months and ranged from 12 to 48 months. We analyzed the primary tumors by ascertaining/measuring tumor size, depth, middle ear effusion, skull base invasion, and lymphadenopathy. The treatment responses for primary tumors were classified as either atrophy, scar (asymmetric elevation without enhancement), or normalized. The tumor response and the appearance of bone regeneration in the previous destructive part of the skull base were also recorded.

RESULTS

The 23 patients consisted of 12 superficial tumors, for whom treatment results were normalized in 10, atrophy in 1, and scar in 1 and 11 deep tumors for whom treatment results were scar in 6, normalized in 3, and atrophy in 2. Skull base invasion was detected in 6 patients, 5 of whom showed complete healing of skull base destruction after radiotherapy. However, the other patient exhibited an unusual hyperostotic change in the skull base mimicking fibrous dysplasia of the skull base.

CONCLUSIONS

The superficial tumors tended to be radiologically normalized even when they were large. However, the deep tumors mainly changed to scar after radiation therapy. On the other hand, skull base invasion could be normalized after radiotherapy.

Gas generation and clot formation during electrolytic detachment of Guglielmi detachable coils: in vitro observations and animal experiment

BACKGROUND AND PURPOSE

Recent reports describe a high rate of thromboembolic events related to Guglielmi detachable coil (GDC) use in the treatment of cerebral aneurysms. The purpose of this study was to investigate electrolysis-related changes of blood as a potential cause of thromboembolic complications associated with GDC use.

METHODS

For in vitro observations, 15 GDCs (10 conventional coils and five insulated coils) were experimentally detached under microscopic observation. Three coils were detached in normal saline, five in human serum, and seven in heparinized human blood. For animal experiments, two coils were detached in two canine normal common carotid arteries with systemic heparinization. Immediately after detachment, the arteries were exposed, and clot formations were observed.

RESULTS

Significant amounts of gas bubbles were observed in all in vitro observations; more were seen in conventional coils, which required longer detachment times, than in insulated coils. Gas generation started with the growth of tiny bubbles into larger ones. In insulated coils, gas was generated only at the detachment zone, and no difference between saline, serum, and blood environments was observed. During detachment within heparinized blood, clot formations of 2-3-mm diameter were observed at the detachment zones of insulated coils. Animal experiments showed clot formation at the detachment zone, and bubble entrapments around the clots were also found.

CONCLUSION

The electrolytic detachment mechanism of the platinum coil can generate gas bubbles during the application of electric current. In association with electrothrombosis, this phenomenon may be a potential cause of thromboembolic complications during the treatment of cerebral aneurysms by use of GDCs.