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Purpose Many studies have shown that multiparametric magnetic resonance imaging (MRI) may be helpful for differentiating malignant renal cell carcinomas (RCCs) from benign lesions. However, the key imaging characteristics that differ between malignant and benign tumors still require further discussion. Methods We analyzed 60 adult patients diagnosed with 72 small renal masses (SRMs) who received preoperative MRI from 2014 to 2019 at a hospital in Taiwan. The MRI features included conventional MRI parameters, diffusion-weighted imaging (DWI) data, and dynamic contrast-enhanced (DCE) patterns, which were documented and compared among the four common subtypes: clear cell RCC (ccRCC), papillary RCC (pRCC), angiomyolipoma (AML) and other types of RCC. The apparent diffusion coefficient (ADC) values of high- and low-grade RCCs were also analyzed. Results The results show that ccRCC had higher T2-weighted signal intensity than the other three subgroups, a higher arterial wash-in index (AWI) and ADC value than AML and pRCC, and manifested a plateau (n = 9, 25%) or washout (n = 27, 75%) enhancement pattern. AMLs exhibited more intravoxel fat than the other three subtype groups, and half of the AMLs (6 in 12) contained bulk fat. pRCC demonstrated a more progressive (n = 3, 60%) enhancement pattern than the other three subgroups. The ADC value of high-grade RCCs was significantly lower than that of low-grade RCCs. Conclusion These findings may indicate that multiparametric MRI is useful in differentiating among four common pathological types of SRMs, and the ADC value may be helpful in evaluating the histological grade of malignancy.

Breast cancer is a main cause of disease and death for women globally. Because of the limitations of traditional mammography and ultrasonography, magnetic resonance imaging (MRI) has gradually become an important radiological method for breast cancer assessment over the past decades. MRI is free of the problems related to radiation exposure and provides excellent image resolution and contrast. However, a disadvantage is the injection of contrast agent, which is toxic for some patients (such as patients with chronic renal disease or pregnant and lactating women). Recent findings of gadolinium deposits in the brain are also a concern. To address these issues, this paper develops an intravoxel incoherent motion- (IVIM-) MRI-based histogram analysis approach, which takes advantage of several hyperspectral techniques, such as the band expansion process (BEP), to expand a multispectral image to hyperspectral images and create an automatic target generation process (ATGP). After automatically finding suspected targets, further detection was attained by using kernel constrained energy minimization (KCEM). A decision tree and histogram analysis were applied to classify breast tissue via quantitative analysis for detected lesions, which were used to distinguish between three categories of breast tissue: malignant tumors (i.e., central and peripheral zone), cysts, and normal breast tissues. The experimental results demonstrated that the proposed IVIM-MRI-based histogram analysis approach can effectively differentiate between these three breast tissue types.

A tumor-mapping algorithm was proposed to identify the same regions in different passes of automated breast ultrasound (ABUS). A total of 53 abnormal passes with 41 biopsy-proven tumors and 13 normal passes were collected. After computer-aided tumor detection, a mapping pair was composed of a detected region in one pass and another region in another pass. Location criteria, including the radial position as on a clock, the relative distance and the distance to the nipple, were used to extract mapping pairs with close regions. Quantitative intensity, morphology, texture and location features were then combined in a classifier for further classification. The performance of the classifier achieved a mapping rate of 80.39% (41/51), with an error rate of 5.97% (4/67). The trade-offs between the mapping and error rates were evaluated, and Az = 0.9094 was obtained. The proposed tumor-mapping algorithm was capable of automatically providing location correspondence information that would be helpful in reviews of ABUS examinations.

The purpose of the technical note is to introduce the complex coil assisted coil embolization method in the treatment of intracranial small aneurysm, in order to enhance the safety of the procedure. The first microcatheter was navigated into the aneurysm sac and the ultrasoft coil was used as the embolization coil. If the embolizations coil could not stay within the aneurysm sac smoothly, such as coil herniation into parent artery during the delivery process. The second microcatheter would be navigated to the aneurysm level in the parent artery. Another complex coil was delivered within the parent artery via the second microcatheter to provide the neck bridge effect in order to enhance the stability of embolization coil. Besides, the protection coil will not disturb the parent artery flow. While the embolization coil was put into the aneurysm sac smoothly under the help of complex protective coil, the protective coil was then withdrawn gently. We use the most magnified view, dual-plane approach simultaneously to observe the stability of embolization coil. The embolization coil would be detached without any evidence of coil motion or vibration. The new method could provide the physiological protective method, without leaving any protective device such as stent within the parent artery.

In Taiwan, breast cancer has become the second leading type of cancerous diseases among women. The incidence and mortality rates keep rising, and mammography remains to be the only effective screening technique which is capable of detecting breast cancer at an early stage. High mammographic density is a strong risk factor for breast cancer. Based on BI-RADS categories, mammograms are classified into four categories (D1-D4) based on the percentage of dense area (PDA). However, reporting of breast density suffers from high inter and intra observer variability. Because the risk of breast cancer is at least three times greater in women with density (D3&D4) than in women with density D1, this paper proposes a local entropy method to identify the higher density (D3&D4) from (D1&D2) by two features. There are 406 mammograms with four categories collected for the test. The higher density (D3&D4) can be identified from lower density (D1&D2) in the correction of 100%. The Az of receiver operating characteristic curve of 0.9996 can be achieved.

Breast cancer is one of Taiwan's female predilection cancers, screening for breast cancer through the mammography has been considered one of the most effective method, since breast cancer screening must have high professional, it is necessity and urgency to strengthen training. Diagnosis of breast cancer skills needed long-term clinical study and accumulated experience, most students often spend a lot of time and effort but still not get the hang of breast diagnostics. This research proposes the design of a learning system for training students in the interpretation of mammograms and diagnosis of breast cancer for beginners. This mammography e-learning system makes available image annotation editor that allow the students to draw the lesion of the breast, to discover breast cancer tissue. Moreover, the e-learning system is integrated with a test system that includes a feedback mechanism to allow students to be reviewed after completion of the test, all the resources are accessible via the web-browser. We expect that through this e-learning system allows medical students without time limit and place limit for learning, and looked forward to further combine others medical curriculum.

In this study, we aimed to evaluate whether patients with left to right shunt coronary artery fistula (LRSCAF) are predisposed to developing pulmonary hypertension and right ventricular dysfunction compared with healthy individuals. The value of cardiac CT findings in determining the necessity of intervention for these patients was investigated. We retrospectively studied 19 patients with LRSCAF and 19 healthy patients. Several parameters were observed on cardiac CT by two radiologists, including pulmonary trunk diameter (PA diameter), right ventricular diameter (RVD), left ventricular diameter (LVD), RVD/LVD ratio, septal bowing and CT score of right ventricular dysfunction (CSRVD). Data from both groups were compared. The inter- and intra-observer variabilities and correlations were examined. The disease group was further divided into intervention (n = 9) and non-intervention (n = 10) groups, and their data were compared. All cardiac CT findings showed significant intra- and inter-observer correlation without significant variability. Mann-Whitney U tests and χ(2) analysis showed that PA diameter, RVD/LVD ratio acquired from two observers, and CSRVD were higher in the disease group than in the control group (all P values 0.05 for χ(2) and almost all P values 0.05 for Mann-Whitney U). The RVD/LVD ratio and CSRVD were higher in the intervention group than in the non-intervention group (all P values 0.05). Receiver operating curve analysis identified RVD/LVD = 1.036 and CSRVD = 3.5 as the best cut-off values to determine the necessity of further intervention. Patients with LRSCAF are more predisposed to pulmonary hypertension and right ventricular dysfunction compared with the normal population. RVD/LVD 1.0 and CSRVD ≥ 4.0 may determine the necessity of intervention for patients with LRSCAF.

With the increased availability of multi-detector row CT, indirect CT venography has become an important non-invasive image modality for patients with suspected deep vein thrombosis. Use of indirect CT venography can not only diagnose/exclude deep vein thrombosis, but can also determine if there are other anomalies or diseases which might contribute to the patient's symptoms. In this pictorial essay, we introduce the scanning protocol, post-processing techniques, and interpretation algorithm used in widely available 64 multi-detector row technology. We discuss several cases, including deep vein thrombosis in acute and chronic stages, anatomic variation, vena cava filter, and collateral veins. Lastly, we consider alternative diagnoses including varicose veins, infection, prosthesis failure of arthroplasty, traumatic vessel injury, and other musculoskeletal conditions. Radiologists should be familiar with the comprehensive interpretation of indirect CT venography to facilitate differential diagnosis and further treatment decision.

Background: To evaluate the safety and protective effect of relative undersized coil with loose coil core in the clinical dilemma condition—very small (43.0 mm) ruptured intracranial aneurysm. Methods: We studied 12 patients (4 men, 8 women) who had suffered from acute ruptured small intracranial aneurysms (2-3 mm in size, with SAH presentation). All subjects underwent a single coil embolization procedure. An undersized coil (equivalent to the neck size or 0.5 mm smaller than the aneurysm diameter) was chosen as the embolizer. Based on the postembolization angiogram, subjects were divided into 2 groups. One was labeled as the initial complete obliteration group (NR) and the other as the incomplete obliteration group (SR). Fisher exact test and the Wilcoxon rank sum test were used to for statistical analysis. Results: The technical success rate was 100% without any procedure-related complication. The follow-up interval ranged from 6 to 32 months. No episode of rebleeding or coil migration could be defined in the admissive and following period. Loose coil core were seen in all patients. The total recurrent rate was 8.3% (1/12); only one patient suffered from recurrent lesion in SR group. Conclusion: The preliminary result showed that under-sized coil packing with loose coil core could provide the protective effect and prevent from further rebleeding for very small ruptured aneurysms. It should be considered as an alternative option in the treatment of acute ruptured very small aneurysms when other conventional strategies are not feasible.

OBJECTIVE. CT-guided core biopsy is playing an increasing role in the diagnosis of benign disease, cellular differentiation, somatic mutation analysis, and molecular fingerprint analysis.CONCLUSION. In this article, we summarize the basic concepts, protocols, and techniques that we use for CT-guided core biopsy of lung lesions to assist radiologists in obtaining diagnostic specimens while reducing preventable complications.

Subdural hematoma (SDH) of the spine following intracranial hemorrhage is extremely rare. We present a 35-year-old woman who suffered from headache and dizziness initially, and then lower back pain, lower limb weakness and paraparesis gradually developed within 1–2 weeks. Magnetic resonance imaging revealed intracranial and spinal SDH. No vascular abnormality was seen by brain and spinal angiography. Platelet count, prothrombin time, activated partial thromboplastin time, and inflammatory markers, including C-reactive protein, were normal. A diagnosis of spontaneous spinal and intracranial SDH was then confirmed surgically. Postoperative recovery was uneventful.

BackgroundGastrointestinal stromal tumors (GISTs) are specific, generally Kit (CD117)-positive, mesenchymal tumors of the gastrointestinal tract encompassing a majority of tumors previously considered gastrointestinal smooth muscle tumors. Our aim was to characterize the computed tomographic findings and predict malignant risk from computed tomography for the evaluation of GISTs.MethodsThe computed tomographic images of 39 patients with pathologically and immunohistochemically proven GISTs were reviewed by 2 radiologists, and the final interpretations were reached by consensus. Images were assessed for the size, contour, growth pattern, boundary, degree of enhancement, and necrosis of the tumors. The presence of calcification within the lesions, abdominal lymphadenopathy, ascites, and bowel obstruction were also recorded. Categorical variables were compared using Fisher's exact test. Univariate and multivariate logistic regression analyses were used for selection of significant predictors of high-risk malignancy. In addition, the relationships between computed tomographic features and tumor size were assessed by means of nonparametric univariate analysis with the Mann–Whitney U test and Kruskal–Wallis test.ResultsBoth old age and larger tumor size (≥ 5 cm) were statistically significant in the univariate logistic analysis for high-risk malignant tumors (p < 0.25). However, in multivariate logistic regression, only larger tumor size (≥ 5 cm) was found to have final statistical significance for high-risk malignant GISTs (p < 0.05). In addition, more exophytic growth pattern (p < 0.01), more lobulated appearance (p < 0.01), good enhancement (p < 0.05), and more necrosis (p < 0.01) of masses were more often observed in larger GISTs than small ones on computed tomography.ConclusionLarger tumor size (≥ 5 cm) was found to have a predictive value with respect to high-risk malignant GISTs.

A 58-year-old man with acute type B aortic dissection presented with right lower limb cyanosis, mesenteric ischemia, and acute renal failure. He was treated with extraanatomic right axillofemoral bypass surgery alone, recovered completely from renal, mesenteric, and lower extremity malperfusion shortly thereafter, and lived free of symptoms for the following year. Follow-up computed tomography angiograms documented adequate expansion of the true aortic lumen and good perfusion of visceral organs. Thus, managing such patients with coexisting visceral and extremity malperfusion may be accomplished with axillofemoral bypass exclusively, which can relieve ischemia of upstream abdominal organs and downstream lower extremities effectively and durably.

A 63-year-old woman was admitted to our hospital due to a grade III systolic murmur over the pulmonary area. A chest x-ray ([Figure 1A][1]) showed cardiomegaly with abnormal vascular shadow over the left atrium area. Transthoracic echocardiography showed coronary artery drainage into pulmonary

70-year-old man, with the history of rheumatic Amitral valvulopathy, prosthetic mitral valve replacement, and two subsequent surgical reinterventions for infective endocarditis and paravalvular leak, presented with severe hemolytic anemia. Paravalvular leak of his prosthetic mitral valve was diagnosed. He received closure with two Amplatzer duct occluders and had symptomatic improvement. Unexpectedly, poor motion of the prosthetic valve was noted 5 months later. Multidetector-row computed tomography revealed closure of both leaflets of the mitral prosthesis in systole (Fig 1A; Ao 1⁄4 aorta; LA 1⁄4 left atrium; LV 1⁄4 left ventricle). During diastole (Fig 1B), one of the valve leaflets

OBJECTIVE. Patent arteriovenous fistula (AVF) is related to better prognosis and quality of life for patients on long-term dialysis. When AVF dysfunction is suspected, MDCT is a good noninvasive tool for evaluating the entire AVF structure and determining reversible conditions for treatment. The aim of this article is to introduce the scanning and interpretation techniques and to illustrate the conditions related to early and late fistula failures.CONCLUSION. MDCT is a fast, noninvasive, and accurate technique for diagnosing AVF complications. Radiologists familiar with these techniques can help to improve the prognosis and quality of life for hemodialysis patients.

Recently, CT pulmonary angiography (CTPA), especially performed with multi-detector row CT, has become a key imaging modality for pulmonary embolism. However, CTPA that was performed under clinical suspicion of pulmonary embolism has been shown to lead to high prevalence of alternative diagnosis, up to 25.4%. A comprehensive evaluation of pulmonary and extrapulmonary abnormalities including cardiovascular lesions is critical in proper diagnosis and patient care. Radiologists should be familiar with the comprehensive interpretation of CTPA to facilitate differential diagnosis and further treatment decision.

Trisomy 18 syndrome is the second most common multiple malformation syndrome. The incidence is about 0.3 per 100 newborn babies. More than 130 different abnormalities have been noted in the literature on patients with the trisomy 18 syndrome. Trisomy 18 includes a broad spectrum of anomalies and malformations, among which we found Dandy-Walker malformation (DWM) rarely mentioned. DWM is estimated to occur in approximately 1 in 25,000 to 30,000 live births. The major components of DWM are the following: partial or complete absence of the cerebellar vermis, a posterior fossa cyst continuous with the fourth ventricle, and hydrocephalus. Although DWM has been associated with many chromosomal abnormalities and genetic syndromes in live birth, trisomy 18 with DWM is a rare condition. Here we present a female newborn with intrauterine growth retardation and multiple congenital abnormalities including: craniofacial anomaly, tracheoesophageal fistula, esophageal atresia, absent radius and thumb, short ulna, clenched hands, ventricular septal defect, coarctation of the aorta, patent ductus arteriosus, Meckel's diverticulum, ectopic pancreas in the ileum, and DWM. Her chromosome karyotype was 47,XX,+18. This is a case of Trisomy 18 with multiple rare malformations.

Congenital mesoblastic nephroma (CMN) is a rare benign tumor that occurs during the neonatal period and early infancy. The vast majority of these tumors present as asymptomatic palpable abdominal masses. We describe an unusual presentation of a CMN in a 10-month-old male infant who presented with massive hematuria and the development of hemorrhagic shock. Abdominal ultrasound showed a heterogeneous solid complex mass measuring 4.8 x 3.5 cm arising from the upper pole of the left kidney. The patient was resuscitated using intravenous fluids and blood transfusions because persistent massive bloody urine leading to progressive shock occurred the night of the admission day. Preoperative diagnosis was possible Wilms tumor of the left kidney. The histopathological findings were consistent with the character of a cellular variant of CMN. The patient was free of recurrence and metastasis at the 2-year follow-up examination. Our case report suggests that CMN is a rare benign renal tumor during infancy and may present with unusual massive hematuria and shock.

Systemic and fatal arterial air embolism during the computed tomography (CT) scan is rarely reported in English-based literature. Iatrogenic air embolism happening during the CT scan is often related to the injector, usually venous air embolism and asymptomatic. We report one fatal and extensive systemic arterial air embolism because of one error that happened during a brain CT scan. The mechanism is different from the reported cases in the literature. The possible mechanism and pathogenesis are well discussed to alert clinicians and prevent the recurrence of such complication.