Usefulness of Preoperative 18F-FDG PET/CT for Patients with Thymic Epithelial Tumors.

BACKGROUND: The purpose of this study was to investigate the relationship between preoperative FDG-PET parameters and the World Health Organization (WHO) classification or Masaoka staging system of thymic epithelial tumors. METHODS: We retrospectively reviewed 32 patients with histologically proven thymic epithelial tumors who underwent FDG-PET/CT before surgical resection. FDG-PET parameters, including the maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolytic activity (TLG), were measured. These PET parameters were compared in the Masaoka staging system and WHO classification. A receiver operating characteristics (ROC) analysis was performed to identify the cut-off values of PET parameters for the accurate differentiation of early and advanced stages in the Masaoka staging system. RESULTS: There were 17 low-risk thymomas (1 type A, 9 type AB, and 7 type B1), 8 high-risk thymomas (4 type B2 and 4 type B3), and 7 thymic carcinomas (7 squamous cell carcinoma). Their Masaoka stages were as follows: 24 in the early stage (stages I and II) and 8 in the advanced stage (stage III). Regarding the WHO classification, only SUVmax showed a significant difference (P < 0.05). In the Masaoka stage, all PET parameters were significantly higher in the advanced stage than in the early stage (P < 0.05). In the ROC analysis to predict the early and advanced stages in thymic epithelial tumors, the area under the curve was the highest for TLG among the PET parameters examined and the cut-off value of TLG for discriminating the early from advanced stage with maximal sensitivity and specificity was 30.735. CONCLUSION: Although volumetric PET parameters, such as MTV and TLG, did not correlate with the WHO classification, a significant correlation was observed between SUVmax and the WHO classification. In the Masaoka staging system, volumetric PET parameters may achieve more precise staging than SUVmax.

Assessment of myocardial fibrosis using T1-mapping and extracellular volume measurement on cardiac magnetic resonance imaging for the diagnosis of radiation-induced cardiomyopathy.

Radiation-induced heart disease (RIHD) is a serious side effect of thoracic radiation therapy (RT) and is associated with significant morbidity and mortality. Radiation-induced cardiomyopathy (RICM) is one of the manifestations of RIHD, which represents with left ventricular (LV) systolic and diastolic dysfunction due to myocardial fibrosis. Although the diagnosis of RIHD is challenging and is generally an exclusion diagnosis, multimodality imaging including echocardiography, cardiac computed tomography and cardiac magnetic resonance (CMR) imaging could help the diagnosis. Herein, we report a case of 70-years-old male, who had been treated with chemo-radiation therapy for early esophageal cancer, was suffered from medically refractory heart failure due to severely reduced LV systolic function and constrictive pericarditis 8 years after chemo-radiation therapy. Although no gadolinium-enhancement (LGE) was detected on CMR, T1 mapping depicted increased extracellular matrix volumes of 45%, which suggested global myocardial fibrosis. Histopathological analysis by endomyocardial biopsy (EBM) revealed marked degeneration of myocytes and interstitial fibrosis, while vacuolation in myocytes which is characteristics of chemotherapy induced cardiomyopathy was not specific by electron microscopy. Therefore, we diagnosed that the present case was likely to the RICM. .

Role of Neuroimaging on Differentiation of Parkinson's Disease and Its Related Diseases.

An accurate diagnosis of Parkinson's disease (PD) is a prerequisite for therapeutic management. In spite of recent advances in the diagnosis of parkinsonian disorders, PD is misdiagnosed in between 6 and 25% of patients, even in specialized movement disorder centers. Although the gold standard for the diagnosis of PD is a neuropathological assessment, neuroimaging has been playing an important role in the differential diagnosis of PD and is used for clinical diagnostic criteria. In clinical practice, differential diagnoses of PD include atypical parkinsonian syndromes such as dementia with Lewy bodies, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, caused by a striatal dopamine deficiency following nigrostrial degeneration. PD may also be mimicked by syndromes not associated with a striatal dopamine deficiency such as essential tremor, drug-induced parkinsonism, and vascular parkinsonism. Moreover, difficulties are associated with the clinical differentiation of patients with parkinsonism from those with Alzheimer's disease. In this review, we summarize the typical imaging findings of PD and its related diseases described above using morphological imaging modalities (conventional MR imaging and neuromelanin MR imaging) and functional imaging modalities (99mTc-ethyl cysteinate dimer perfusion single photon emission computed tomography, 123I-metaiodobenzylguanidine myocardial scintigraphy, and 123I-FP-CIT dopamine transporter single photon emission computed tomography) that are clinically available in most hospitals. We also attempt to provide a diagnostic approach for the differential diagnosis of PD and its related diseases in clinical practice.

Bilateral Ovarian Tumors on MRI: How Should We Differentiate the Lesions?

BACKGROUND: We investigated the distinguishing pathological features of bilateral ovarian tumors using magnetic resonance (MR) imaging. METHODS: Eighty-six patients with bilateral ovarian tumors on MR imaging were evaluated. The pathological diagnosis was investigated, and the results were subjected to statistical analysis using Mann-Whitney U test, Fisher's exact test, Chi-squared test and receiver operating characteristic (ROC) curve to determine the features useful for the differentiation of distinct types of lesions. RESULTS: The diagnosis of bilateral ovarian tumors was confirmed in eighty-one patients and the majority of the lesions were further classified into serous carcinoma (n = 36), mature teratoma (n = 20) and metastasis (n = 12). We assessed the existence of factors useful for the MR imaging differentiation between metastasis and serous carcinoma or primary malignant ovarian tumors. Cancer antigen (CA) 125 serum level and maximum tumor diameter were significantly different between metastasis and serous carcinoma and similarly, between metastasis and primary malignant ovarian tumors. MR imaging morphology, ascites and peritoneal implants did not show any significant difference between the different types of lesions. CONCLUSION: Within our patient cohort, most bilateral ovarian tumor lesions were determined to be serous carcinoma, mature teratoma or metastasis. CA 125 serum level and maximum tumor diameter are useful markers for the differentiation between metastasis and serous carcinoma or primary malignant ovarian tumors.

Vanishing Parotid Tumors on MR Imaging.

BACKGROUND: Of all parotid gland tumors, only oncocytoma has been reported to appear isointense to the parotid gland, namely vanishing, on fat-saturated T2 and T1 postcontrast gadolinium-enhanced magnetic resonance imaging (MRI). The purpose of this study was to evaluate vanishing of parotid tumors on conventional MRI with and/or without postcontrast gadolinium-enhancement and on diffusion weighted imaging (DWI). METHODS: In 8 of 51 patients, ten parotid gland tumors had homogeneously enhanced lesions and were retrospectively analysed. Comparisons of signal intensity between those parotid tumors and parotid glands and evaluations of vanishing were performed on T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), fat-suppressed T2WI (FS-T2WI), postcontrast gadolinium-enhanced T1WI (CE-T1WI) and fat-suppressed CE-T1WI (FS-CE-T1WI), DWI as well as apparent diffusion coefficient (ADC). RESULTS: Ten parotid gland tumors consisted of five Warthin tumors, two pleomorphic adenomas, two parotid carcinomas (small cell carcinoma and adenoid cystic carcinoma) and one oncocytoma. All tumors showed hypointensity on T1WI and hyperintensity on DWI. Nine of ten tumors showed vanishing on the other MR sequences. All Warthin tumors showed vanishing on FS-T2WI, FS-CE-T1WI and the ADC map. One oncocytoma showed vanishing on FS-T2WI and the ADC map and hyperintensity on FS-CE-T1WI. All pleomorphic adenomas showed vanishing on T2WI and CE-T1WI. One adenoid cystic carcinoma showed vanishing only on CE-T1WI. CONCLUSION: Vanishing of parotid tumors can be observed not only on FS-T2WI and FS-CE-T1WI but also on T2WI, CE-T1WI and ADC mapping.

Utility of intravoxel incoherent motion magnetic resonance imaging and arterial spin labeling for recurrent glioma after bevacizumab treatment.

Background Detecting recurrence of glioma on magnetic resonance imaging (MRI) is getting more and more important, especially after administration of new anti-tumor agent. However, it is still hard to identify. Purpose To examine the utility of intravoxel incoherent motion (IVIM) MRI and arterial spin labeling-cerebral blood flow (ASL-CBF) for recurrent glioma after initiation of bevacizumab (BEV) treatment. Material and Methods Thirteen patients (7 men, 6 women; age range = 41-82 years) with glioma (high grade, n = 11; low grade, n = 2) were enrolled in the study. IVIM parameters including apparent diffusion coefficient (ADC), true diffusion coefficient (D), and perfusion fraction (f) were obtained with 14 different b-values. We identified tumor progression during BEV therapy by MRI monitoring consisting of diffusion-weighted imaging (DWI), fluid-attenuated inversion recovery (FLAIR) imaging, and contrast-enhanced T1-weighted (CE-T1W) imaging by measuring tumor area. We also measured each parameter of IVIM and ASL-CBF, and calculated relative ADC (rADC), relative D (rD), relative f (rf), and relative CBF (rCBF) by obtaining the ratio between each area and the contralateral cerebral white matter. We calculated the rate of change (Δ) by subtracting values from those from the preceding MRI study, and obtained Spearman's rank correlation coefficient (rs). Results Tumor progression was identified in nine patients (high grade, n = 7; low grade, n = 2). Negative correlations were identified between ΔrD and ΔDWI area (rs = -0.583), and between ΔrD and ΔCE-T1W imaging area (rs = -0.605). Conclusion Tumor progression after BEV treatment can be identified by decreasing rD.

Superficial Siderosis Associated with Pineal Cavernous Malformation.

BACKGROUND: Cavernous malformations in the pineal region are rare and difficult to anticipate from preoperative evaluation in patients with pineal apoplexy. We herein report the first case of a pineal cavernous malformation with superficial siderosis. Radiological findings were helpful in identifying the presence of the cavernous malformation. CASE DESCRIPTION: A 47-year-old female presented with a 4-month history of progressive headache, nausea, and dizziness. She complained of double vision and exhibited upward gaze palsy and papilledema on fundoscopy. Radiological examination revealed subacute hemorrhage in the pineal region and enlarged lateral ventricles. Furthermore, T2-star-weighted gradient-echo magnetic resonance imaging demonstrated a linear hypointensity along the pial surface of the cerebral cortex, brainstem, and cerebellum, indicating hemosiderin deposition consistent with superficial siderosis. Suspecting the presence of a cavernous malformation based on the radiological findings of superficial siderosis, we performed total mass resection. The postoperative course was uneventful and her preoperative symptoms resolved completely. CONCLUSION: Radiological findings of superficial siderosis on T2-star-weighted gradient-echo imaging are useful to making a diagnosis of cavernous malformation in cases of pineal apoplexy. They are also important for making the treatment decision to perform total mass resection, which is the best curative method for pineal cavernous malformations.

Non-Surgical Management of Bile Leakage After Hepatectomy: A Single-Center Study.

BACKGROUND: Bile leakage after hepatectomy is a common complication. The purpose of the present study was to retrospectively evaluate the usefulness of non-surgical management of bile leakage after hepatectomy, using 12-year data from a single center study. METHODS: Data from 15 patients (13 men, two women; mean age 67.1 ± 7.0 years) who had undergone non-surgical management for bile leakage between January 2005 and November 2017 were retrospectively reviewed. RESULTS: We categorized bile leakage as central (n = 5) or peripheral (n = 10) leakage based on communication with the biliary tree. Percutaneous bile leakage drainage and/or endoscopic naso-biliary drainage (ENBD) (n = 2) or the rendezvous technique (n = 3) was successfully performed in five central-type cases, while all peripheral-type cases were treated with drainage alone; only one case required additional ethanol ablation. Bacterial bile cultures were positive in 11 cases and negative in four cases. The drainage catheters were removed after complete resolution in 13 cases (86.7%), while two patients with cases of peripheral-type leakage died due to cancer progression while the drain was in place. No case needed conversion to reoperation. The mean duration of drainage therapy in all cases was 210.1 ± 163.0 days (range 17-531 days), with 316.8 ± 180.8 days in the central type and 156.7 ± 131.5 days in the peripheral type; this duration was not significantly different (P = 0.129). CONCLUSION: Non-surgical treatment is a minimally invasive and effective management strategy for postoperative bile leakage and the modality used depends on the type of bile leakage encountered.

The spectrum of imaging appearances of müllerian duct anomalies: focus on MR imaging.

Müllerian duct anomalies (MDAs) are the result of incomplete development, vertical or lateral fusion, or absorption of the müllerian ducts. The range of anomalies includes uterovaginal agenesis or hypoplasia, unicornuate uterus, uterus didelphys, bicornuate uterus, septate uterus, and arcuate uterus. Correct diagnosis and classification of these anomalies are essential because pregnancy outcomes and treatment options vary between the types of anomaly. Furthermore, early identification of MDAs helps to avoid prolonged symptomatic periods and the complications that may subsequently arise, such as infertility, endometriosis, and neoplasm. Although many of these abnormalities are initially diagnosed by ultrasound or hysterosalpingography, MR imaging is the most accurate noninvasive modality available for classification of the various anomalies because of its better anatomic assessment compared with other diagnostic modalities. Familiarity with the wide variety of MDA presentations can help in the planning of appropriate treatment.

Volume Measurement by Diffusion-Weighted Imaging in Cervical Cancer.

BACKGROUND: The aim of this paper was to evaluate the validity of tumor volume measurement using diffusion-weighted (DW) imaging in cervical cancer. METHODS: In this retrospective study, 22 patients, who underwent preoperative 3.0 T MR examinations with DW imaging were evaluated. Tumor volume measurement by oblique axial (short axis to the uterine cervix) T2-weighted imaging was performed by manually outlining the tumor on the monitor. The area of tumor in each slice was multiplied by the slice profile (slice thickness plus intersection gap), and the total tumor volume was calculated by summation of these obtained volumes. Meanwhile, one experienced radiological technologist generated three-dimensional DW images of cervical cancer using a volume-rendering algorithm at a computer workstation, and tumor volume was automatically calculated in the workstation. Analysis via the intraclass correlation coefficient (ICC) and Bland-Altman plots were used to assess the validity and reliability of these methods. RESULTS: Between tumor volumes measured by T2-weighted imaging methods and DW imaging methods, the ICC was excellent (0.962). The 95% limits of agreement of volume measurement were -52.7 and 35.7 mL (mean difference, -8.5 mL). In regards to intra-observer variability, the ICC was excellent (0.963). The 95% limits of agreement of volume measurement were -42.2 and 47.4 mL (mean difference, 2.6 mL). CONCLUSION: DW imaging can be used to measure cervical cancer volume.

Differentiating parotid tumors by quantitative signal intensity evaluation on MR imaging.

BACKGROUND: There have been no reports about quantitative evaluations of enhancing components of parotid tumors on conventional MR imaging. PURPOSE: To evaluate the signal intensity of the enhancing components of tumors, including pleomorphic adenomas (PAs), Warthin tumors (WTs) and malignant tumors (MTs), on various MR sequences and to assess the usefulness of quantitative evaluations for differentiation among the three groups of tumors. MATERIAL AND METHODS: A total of 39 histologically proven tumors, including 15 PAs, 17 WTs and 7 MTs, were enrolled in this study. The tumor-to-spinal cord contrast ratio (TSc-CR) was calculated by dividing the signal intensity of the lesion by that of the spinal cord on MR sequences, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI) and postcontrast gadolinium-enhanced T1WI (CE-T1WI). The mean apparent diffusion coefficient (ADC) value was selected in each tumor. Furthermore, the differences in the TSc-CRs and the ADC values among the three groups of tumors were statistically evaluated. Cutoff values were determined for the prediction of tumor histology. RESULTS: The TSc-CRs of PAs were significantly higher than those of WTs and MTs on T2WI and CE-T1WI. The sensitivities and specificities were 100% and 87.5%, respectively, at a cutoff value of 1.31 for the TSc-CR of T2WI; and 83.3% and 100%, respectively, at a cutoff value of 2.00 for the TSc-CR of CE-T1WI. For the ADC values, sensitivity and specificity for discriminating PAs from WTs or MTs were both 100% when the cutoff value of the ADC was set at 1.40×10-3mm2/s. CONCLUSION: ADC maps and the quantitative evaluations using the TSc-CRs on T2WI and CE-T1WI were useful for discriminating WTs or MTs from PAs. However, discrimination between WTs and MTs was difficult using any MR sequence.

Pictorial review of 18F-FDG PET/CT findings in musculoskeletal lesions.

We herein reviewed 18F-fluoro-2-deoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) findings in a number of musculoskeletal lesions including malignant tumors, benign tumors, and tumor-like lesions with correlations to other radiographic imaging modalities, and described the diversity of the 18F-FDG PET/CT findings of this entity. Malignant primary musculoskeletal tumors are typically 18F-FDG avid, whereas low-grade malignant tumors show mild uptake. Benign musculoskeletal tumors generally show a faint uptake of 18F-FDG, and tumor-like conditions also display various uptake patterns of 18F-FDG. Although musculoskeletal tumors show various uptakes of 18F-FDG on PET/CT, its addition to morphological imaging modalities such as CT and MRI is useful for the characterization and differentiation of musculoskeletal lesions.

Combination Therapy of Interventional Radiology and Surgery for Infarction of the Small Intestine Caused by Portal Vein and Mesenteric Vein Thrombosis: A Patient Report.

We report the case of a man in his 70s who suffered from intestinal infarction caused by acute portal vein and mesenteric vein thrombosis (PVMVT). Combination therapy with percutaneous transcatheter thrombectomy and surgical bowel resection was successfully performed, and a satisfactory outcome was achieved. Intestinal infarction caused by PVMVT can be fatal and has a high mortality rate even if surgical resection is performed. The combination therapy of interventional radiology and surgery might be a safe and effective method for patients with this life-threatening condition.

Three cases of mediastinal pancreatic pseudocysts.

A rare complication of acute or chronic pancreatitis is the formation of a mediastinal pancreatic pseudocyst (MPP), which is caused by tracking of pancreatic fluids through anatomical openings of the diaphragm into the mediastinum. Herein, we report the imaging characteristics of three cases of this condition. Our results revealed three features in common: (i) the connection between the mediastinum and the pancreatic cystic lesion; (ii) the presence of pleural effusions; and (iii) imaging findings consistent with chronic pancreatitis, such as pancreatic atrophy and calcifications and dilatation and/or stricture of main pancreatic duct (MPD). Serial diameter changes of the MPD and of the adjacent pseudocysts were necessary for the determination of the therapeutic strategy used in each case.