Endovascular and Percutaneous Embolotherapy for the Body and Extremity Arteriovenous Malformations.

Arteriovenous malformations (AVMs) consist of abnormal communications between the arteries and veins. They can involve any part of the body and extremity and grow in proportion to age and in response to hormonal influence or trauma. When symptoms progress from Schöbinger clinical stage II to III, transcatheter and/or direct puncture embolization are less-invasive and repeatable options for symptom palliation. The goal of embolization is to obliterate the AV shunt, and the choice of lesion access and embolic agents is based on the individual anatomy and flow. Embolization can be technically challenging due to complex vascular anatomy and morbidity risks. Therefore, a multidisciplinary management is essential for the diagnosis and therapeutic intervention of AVMs.

Comparison of reduced field-of-view DWI and full field-of view DWI for the differentiation between non-muscle invasive bladder cancer and muscle invasive bladder cancer using VI-RADS.

PURPOSE: To evaluate whether reduced field-of-view (rFOV) DWI sequence improves the differentiation between non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC) using VI-RADS. MATERIAL AND METHODS: Eighty-nine patients underwent bladder MRI with full field-of-view (fFOV) DWI and rFOV DWI sequence. Images were independently evaluated by 2 radiologists. The sensitivities, specificities, accuracies, and areas under the curve (AUCs) for the differentiation between NMIBC and MIBC with fFOV DWI and with rFOV DWI sequence were calculated using VI-RADS. Apparent diffusion coefficients (ADC) values were measured for each patient and averaged. RESULTS: The sensitivity, specificity, accuracy, and AUC by reader 1 were 92%, 78%, 82% and 0.905 with fFOV DWI, and 92%, 86%, 88% and 0.916 with rFOV DWI sequence, respectively. The sensitivity, specificity, accuracy and AUC by reader 2 were 96%, 76%, 82% and 0.900 with conventional DWI, and 96%, 81%, 85% and 0.907 with rFOV DWI sequence, respectively. The specificity and accuracy of reader 1 were significantly better with rFOV DWI sequence than with fFOV DWI, in contrast there was no significant difference for the others. The average of ADC values of fFOV DWI and rFOV DWI sequence were 1.004×10-6 mm2/s and 1.003×10-6 mm2/s, respectively. CONCLUSION: The diagnostic ability of rFOV DWI sequence may be better than that of fFOV DWI using VI-RADS for the differentiation between NMIBC and MIBC regardless of image-reading experience, it is controversial.

[Brain Tumor].

CT numbers depend on the electron density and the effective atomic number of materials. The CT numbers of the cerebrospinal fluid, gray matter, and white matter are 0 HU, 30-40 HU, and 20-30 HU, respectively. We should interpret the head CT scan based on the difference between the CT numbers of the white and gray matter. Moreover, we recommend image interpretation by delineating the cortical ribbon. For the detection of brain tumors using MR, T1-weighted and T2-weighted axial images alone are insufficient. It is important to also use other sequences such as FLAIR, diffusion-weighted images, and multi-section images.

Pulmonary Sparganosis: Tunnel Sign and Migrating Sign on Computed Tomography.

A 77-year-old woman presented at our hospital to undergo a close examination of an abnormal shadow which was observed on a chest radiograph. Contrast-enhanced computed tomography (CT) images in the lung window revealed a tortuous tunnel structure (tunnel sign), which was suspected to be the migration path of a parasite. Furthermore, CT images in the mediastinal window showed a linear filling defect from the right inferior pulmonary vein to the venous ostium in the left atrium (migrating sign), which was suspected to be a migrating parasite in the pulmonary vein. Tunnel and migrating signs on chest CT images were helpful in diagnosing pulmonary sparganosis.

Optic Nerve Root Enhancement in Gadolinium-Enhanced Magnetic Resonance Imaging of Rathke's Cleft Cyst.

BACKGROUND: Although most patients with Rathke's cleft cysts (RCCs) remain asymptomatic throughout their lives, visual impairment in RCCs usually indicates surgical interventions, including endoscopic drainage of the cyst. We report a case of RCC with unique findings in the optic nerve root (ONR) by magnetic resonance imaging (MRI). CASE DESCRIPTION: A 58-year-old man admitted to our hospital complained of progressive left visual impairment. Preoperative computed tomography MRI revealed a suprasellar cystic lesion that extended anteriorly, and the bilateral ONRs were lateralized with the cyst and were partially enhanced with gadolinium administration. The cyst content was drained, and the cyst wall was partially removed by endoscopic transsphenoidal surgery. Postoperatively, the patient was administered corticosteroid intravenously for 3 days, and his visual acuity improved dramatically. Postoperative MRI revealed that the volume of the cyst decreased, and the position of the bilateral ONRs normalized. Additionally, enhancement of the ONRs with gadolinium administration was not observed. Histological examination of the surgical specimen revealed a ciliated single-layer columnar epithelium with inflammatory cell infiltration. CONCLUSIONS: To our knowledge, we report the first case of a patient with RCC with ONR enhancement with gadolinium administration on MRI. This unique finding might prove that inflammation is one of the causes of visual impairment in RCC as in optic neuritis.

Reduction of the radiation dose and the amount of contrast material in hepatic dynamic CT using low tube voltage and adaptive iterative dose reduction 3-dimensional.

The purpose of this study was to prospectively evaluate the image quality and the diagnostic ability of low tube voltage and reduced contrast material dose hepatic dynamic computed tomography (CT) reconstructed with adaptive iterative dose reduction 3-dimensional (AIDR 3D).Eighty-nine patients underwent hepatic dynamic CT using one of the 2 protocols: tube voltage of 120 kVp, contrast dose of 600 mgI/kg, and filtered back projection in Protocol A (n = 46), and tube voltage of 100 kVp, contrast dose of 500 mgI/kg, and AIDR 3D in Protocol B (n = 43). The volume CT dose index (CTDIvol) and size-specific dose estimates (SSDEs) were compared between the 2 groups. Objective image noise and tumor to liver contrast-to-noise ratio (CNR) were also compared. Three radiologists independently reviewed image quality. The jackknife alternative free-response receiver-operating characteristic (JAFROC) analysis was performed to compare diagnostic performance.The mean CTDIvol and SSDE of Protocol B (14.3 and 20.2, respectively) were significantly lower than those of Protocol A (22.1 and 31.4, P < .001). There were no significant differences in either objective image noise or CNR. In the qualitative analysis, 2 readers assigned significant lower scores to images of Protocol B for at least one of the 3 phases regarding overall image quality (P < .05). There was no significant difference in the JAFROC1 figure of merit between protocols.Low tube voltage CT with AIDR 3D yielded a reduction in radiation dose and in the amount of contrast material while maintaining diagnostic performance.

Detectability of residual invasive bladder cancer in delayed 18F-FDG PET imaging with oral hydration using 500 mL of water and voiding-refilling.

OBJECTIVE: 2-Fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) imaging is not considered useful for assessing bladder cancer due to the physiological uptake of 18F-FDG in the bladder. Despite reports of the detection of bladder cancer by washing out 18F-FDG from the bladder, such methods are invasive and impractical in the routine practice. The purpose of this study was to evaluate prospectively the utility of oral hydration with 500 mL of water and voiding-refilling, a minimally invasive method that we introduced to enable detection of residual invasive bladder cancer on delayed 18F-FDG PET imaging. METHODS: From January 2015 to December 2017, 267 consecutive patients with bladder cancer underwent 18F-FDG PET/computed tomography scans. Among these patients, 25 (19 men and 6 women; mean age, 72.0 ± 11.3 years) were newly diagnosed as having muscle-invasive bladder cancer by transurethral resection of bladder tumor and T3b or T4 by magnetic resonance imaging (MRI). All patients were orally hydrated with only 500 mL of water and were then instructed to void frequently for 60 min before early 18F-FDG PET imaging. After the scans, they were instructed to hold their urine for 60 min. Then, delayed imaging was performed. Two radiologists evaluated the early and delayed 18F-FDG PET images to determine whether residual invasive bladder cancer could be detected. The maximum standardized uptake values (SUVmax) of the bladder urine and residual tumor site were also measured on early and delayed images. The maximum diameter of the primary bladder tumor was measured on MRI. RESULTS: The sensitivity for detecting residual invasive bladder cancer on early and delayed imaging were 24.0 and 92.0%, respectively (P < 0.001). The SUVmax of the bladder urine on the early and delayed imaging were 34.7 ± 29.7 and 16.0 ± 10.7 (mean ± SD), respectively. The SUVmax of the residual tumor site on the early and delayed imaging were range 15.65-30.83 and 10.06-45.70, respectively. CONCLUSION: Delayed 18F-FDG PET imaging with oral hydration using only 500 mL of water and voiding-refilling is useful for detecting residual invasive bladder cancer.

Pathological findings of uterine tumors preoperatively diagnosed as red degeneration of leiomyoma by MRI.

PURPOSE: Venous infarction of a leiomyoma is known as red degeneration of leiomyoma (RDL) and can be a cause of acute abdomen. Although magnetic resonance imaging (MRI) is the only modality that can depict the inner condition of a leiomyoma, the typical MR findings of RDL are sometimes identified incidentally even in asymptomatic patients. The purpose of this study is to clarify common pathological findings of uterine tumors preoperatively diagnosed as RDL by MRI. METHODS: We diagnosed 28 cases of RDL by MRI from March 2007 to April 2015. The ten lesions subjected to pathological analysis after resection were included in the study and reviewed by a gynecological pathologist. The average time from MRI to operation was 4.7 months. RESULTS: The typical beefy-red color was not observed on the cut surface of the tumor except in one tumor resected during the acute phase. All lesions diagnosed as RDL by MRI had common pathological findings consistent with red degeneration of leiomyoma, including coagulative necrosis. Other common pathological features of RDL besides extensive coagulative necrosis appear to be a lack of inflammatory cell infiltrate or hemorrhage in the entire lesion. CONCLUSIONS: Although RDL is known to cause acute abdomen, its typical MR findings can be observed even in asymptomatic patients in a condition that manifests long after red degeneration. The characteristic pathological findings in both the acute phase and the chronic phase that we found in this study, along with radiology reports, will be helpful references for gynecologists and pathologists in suspecting a history of red degeneration and confirming the diagnosis.

Central Nervous System Involvement of Intravascular Large B-Cell Lymphoma on 18F-FDG PET/CT.

Intravascular large B-cell lymphoma is a rare subtype of extranodal diffuse large B-cell lymphoma. We present a case of intravascular large B-cell lymphoma with central nervous system involvement that can be detected on F-FDG PET and may be useful for applications in biopsy and diagnosis.

A Case of Bilateral Decidualized Endometriomas during Pregnancy: Radiologic-pathologic Correlation.

Clinical differentiation between decidualized endometrioma and malignant transformation still poses difficulties as both are intracystic vascularized excrescences of an endometrial cyst and exhibit similar characteristics on color-flow Doppler sonography. This is a characteristic sonographic finding associated with ovarian cancer, but MRI can provide further information about mural excrescences that can aid in their differential diagnosis; for example, the signal of decidualized endometriomas is isointense with the placenta within the uterus on all sequences and the apparent diffusion coefficient is higher than that of malignant mural nodules. Thus, MRI should be an aid in deciding whether to intervene during pregnancy. However, considering that it is not yet possible to clearly differentiate decidualized endometriomas from ovarian cancer, surgery or watchful observation may still be needed to exclude the possibility of malignancy.

Magnetic resonance imaging findings in atypical polypoid adenomyoma.

OBJECTIVES: This article describes magnetic resonance imaging (MRI) findings in 3 cases of atypical polypoid adenomyoma (APAM). METHODS: Clinical and MRI manifestations of 3 patients with APAM were evaluated. High b value diffusion-weighted and dynamic contrast-enhanced images were performed. The size, shape, site of origin, and signal intensity (SI) of MRI findings were evaluated. RESULTS: All patients (age range, 37-47 years; mean age, 40 years) had a chief complaint of atypical genital bleeding with no history of pregnancy. In 2 cases, cytology of the endometrium was positive, and pathological analysis of curettage specimens indicated endometrioid adenocarcinoma. The MRI revealed an endometrial polypoid mass arising from the upper corpus (50%) or lower uterine segment (50%). Except for 1 tumor that seemed to invade the myometrium of the uterine wall due to its irregular margin, all tumors were well circumscribed. On T2-weighted MRI scans, the SI of the tumor was homogenous and marginally hyperintense, and contained markedly hyperintense cystic foci. On T1-weighted images, all the tumors were isointense relative to the myometrium, and in 1 case, a number of cystic foci showed high SIs. In a dynamic contrast-enhanced study, solid portions other than the cystic foci showed contrast enhancement in the arterial phase and demonstrated a washout pattern or plateau pattern in the late phase. All tumors demonstrated high SIs on diffusion-weighted images. CONCLUSIONS: Differentiating APAM from other malignant polypoid uterine endometrial tumors may still pose difficulties, especially when the tumor seems to invade the myometrium on MRI. Comprehensive clinical information about the patient including age, pathological assessment of the endometrium, and MRI findings should be essential to provide indication for a diagnosis of APAM.