Diagnostic value of multiple b-value diffusion-weighted imaging in discriminating the malignant from benign breast lesions.

OBJECTIVE: The conventional breast Diffusion-weighted imaging (DWI) was subtly influenced by microcirculation owing to the insufficient selection of the b values. However, the multiparameter derived from multiple b-value exhibits more reliable image quality and maximize the diagnostic accuracy. We aim to evaluate the diagnostic performance of stand-alone parameter or in combination with multiparameter derived from multiple b-value DWI in differentiating malignant from benign breast lesions. METHODS: A total of forty-one patients diagnosed with benign breast tumor and thirty-eight patients with malignant breast tumor underwent DWI using thirteen b values and other MRI functional sequence at 3.0 T magnetic resonance. Data were accepted mono-exponential, bi-exponential, stretched-exponential, aquaporins (AQP) model analysis. A receiver operating characteristic curve (ROC) was used to evaluate the diagnostic performance of quantitative parameter or multiparametric combination. The Youden index, sensitivity and specificity were used to assess the optimal diagnostic model. T-test, logistic regression analysis, and Z-test were used. P value < 0.05 was considered statistically significant. RESULT: The ADCavg, ADCmax, f, and α value of the malignant group were lower than the benign group, while the ADCfast value was higher instead. The ADCmin, ADCslow, DDC and ADCAQP showed no statistical significance. The combination (ADCavg-ADCfast) yielded the largest area under curve (AUC = 0.807) with sensitivity (68.42%), specificity (87.8%) and highest Youden index, indicating that multiparametric combination (ADCavg-ADCfast) was validated to be a useful model in differentiating the benign from breast malignant lesion. CONCLUSION: The current study based on the multiple b-value diffusion model demonstrated quantitatively multiparametric combination (ADCavg-ADCfast) exhibited the optimal diagnostic efficacy to differentiate malignant from benign breast lesions, suggesting that multiparameter would be a promising non-invasiveness to diagnose breast lesions.

Prediction of outcomes by diffusion kurtosis imaging in patients with large (≥5 cm) hepatocellular carcinoma after liver resection: A retrospective study.

Purpose: To evaluate preoperative diffusion kurtosis imaging (DKI) in predicting the outcomes of large hepatocellular carcinoma (HCC) after liver resection (LR). Materials and methods: From January 2015 to December 2017, patients with a large (≥5cm) HCC who underwent preoperative DKI were retrospectively reviewed. The correlations of the mean kurtosis (MK), mean diffusivity (MD), and apparent diffusion coefficient (ADC) with microvascular invasion (MVI) or histological grade were analyzed. Cox regression analyses were performed to identify the predictors of recurrence-free survival (RFS) and overall survival (OS). A nomogram to predict RFS was established. P<0.05 was considered as statistically significant. Results: A total of 97 patients (59 males and 38 females, 56.0 ± 10.9 years) were included in this study. The MK, MD, and ADC values were correlated with MVI or histological grade (P<0.01). With a median follow-up time of 41.2 months (range 12-69 months), 67 patients (69.1%) experienced recurrence and 41 patients (42.3%) were still alive. The median RFS and OS periods after LR were 29 and 45 months, respectively. The 1-, 3-, and 5-year RFS and OS rates were 88.7%, 41.2%, and 21.7% and 99.0%, 68.3%, and 25.6%, respectively. MK (P<0.001), PVT (P<0.001), and ADC (P=0.033) were identified as independent predictor factors for RFS. A nomogram including the MK value for RFS showed the best performance, and the C-index was 0.895. Conclusion: The MK value obtained from DKI is a potential predictive factor for recurrence and poor survival, which could provide valuable information for guiding the efficacy of LR in patients with large HCC.

Polydopamine Nanoparticles for Deep Brain Ablation via Near-Infrared Irradiation.

Local resection or ablation remains an important approach to treat drug-resistant central neurological disease. Conventional surgical approaches are designed to resect the diseased tissues. The emergence of photothermal therapy (PTT) offers a minimally invasive alternative. However, their poor penetration and potential off-target effect limit their clinical application. Here, polydopamine nanoparticles (PDA-NPs) were prepared and characterized. Studies were performed to evaluate whether PDA-NPs combined with near-infrared (NIR) light can be used to ablate deep brain structures in vitro and in vivo. PDA-NPs were prepared with a mean diameter of ∼150 nm. The particles show excellent photothermal conversion efficiency. PDA-NPs did not show remarkable cytotoxicity against neuronal-like SH-SY5Y cell lines. However, it can cause significant cell death when combined with NIR irradiation. Transcranial NIR irradiation after PDA-NPs administration induced enhanced local hyperthermia as compared with NIR alone. Local temperature exceeded 60 °C after 6 min of irradiation plus PDA while it can only reach 48 °C with NIR alone. PTT with PDA (10 mg/mL, 3 µL) and NIR (1.5 W/cm2) can ablate deep brain structures precisely with an ablation volume of ∼6.5 mm3. Histological analysis confirmed necrosis and apoptosis in the targeted area. These results demonstrate the potential of NP-assisted PTT for the treatment against nontumorous central neurological diseases.

Low-grade appendiceal mucinous neoplasms confined to the appendix: clinical manifestations and CT findings.

The clinical findings and CT images are investigated in order to fulfill an early preoperative diagnosis and increase awareness of low-grade appendiceal mucinous neoplasm (LAMN) confined to the appendix. 17 cases with histologically proven LAMNs confined to the appendix were included in this study. All patients had received multiphase CT examinations before the surgery. The imaging criteria included shape, size, margin, attenuation, secondary degeneration and internal mass enhancement pattern. In CT images, all cases appeared as oval or tubular cystic masses (average attenuation 20.4±3.6 Hounsfield units), with the longest dimensions ranging from approximately 38 to 106 mm (mean 66.3 mm), and the ratio of length against width was 1.83 in average. The cystic wall was unevenly thickened, with a mean maximal wall thickness of 5.7 mm (>10 mm in 3 cases). The inner capsule wall was rough, and calcification was observed in 3 cases. A few amounts of periappendiceal fat stranding were noted in 2 cases. Mild ring mural enhancement of the cystic wall was seen during the arterial phase, with progressive enhancement during the portal venous phase. In addition, mini enhancing mural nodules was observed in 5 cases. Although preoperative diagnosis of LAMNs confined to the appendix remains challenging, it should be considered when a focal well-defined cystic mass with slightly higher than water attenuation, thickened cystic wall with ring mural enhancement and a characteristic progressive contrast enhancement in CT imaging, especially in older females with non-specific symptoms similar to appendicitis.

Accuracy of Tumor Perfusion Assessment in Rat C6 Gliomas Model with USPIO.

Detailed characterization of the permeability and vascular volume of brain tumor vasculature can provide essential insights into tumor physiology. In this study, we evaluated the consistency of measurements in tumor blood volume and examined the feasibility of using ultrasmall superparamagnetic iron oxide (USPIO) versus gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) as contrast agents for MR perfusion imaging of brain gliomas in C6 Rats. Eighteen rats were intracerebrally implanted with C6 glioma cells, randomly divided into two groups and examined by 3.0T perfusion MR imaging with Gd-DTPA and USPIO. Tumor relative cerebral blood volume (rCBV) and relative maximum signal reduction ratio (rSRRmax) were created based on analysis of MR perfusion images. The mean values for rCBV were 2.09 and 1.57 in the USPIO and the Gd-DTPA groups, respectively, and rSRRmax values were 1.92 and 1.02 in the USPIO and the Gd-DTPA groups, respectively, showing signifi cant differences in both rCBV and rSRRmax between the USPIO and the Gd-DTPA groups (P < 0.05). The results showed that early vascular leakage occurred with gadolinium rather than USPIO in perfusion assessment, revealing that USPIO was useful in perfusion MR imaging for the assessment of tumor vasculature.

Three-dimensional proton magnetic resonance spectroscopy and diffusion-weighted imaging in the differentiation of incidental prostate carcinoma from benign prostate hyperplasia.

The present study evaluated three-dimensional proton magnetic resonance spectroscopy (MRS) and diffusion-weighted imaging (DWI) features in differentiating incidental prostate carcinoma (IPCa) and benign prostate hyperplasia (BPH) in the central gland of the prostate. The clinical and imaging data of 9 patients with IPCa, 118 patients with BPH [including those with glandular hyperplasia (GH), stromal hyperplasia (SH) and mixed hyperplasia (MH)], were retrospectively analyzed. The mean (choline + creatine)/citrate (CC/C) value of 3D MRS, the apparent diffusion coefficient (ADC) value and the minimal ADC value of DWI were compared between carcinoma and non-carcinoma tissues. The mean CC/C values were 1.04±0.28, and 1.09±0.58 in IPCa and BPH, respectively (t=-0.205, P=0.838). No significant difference in CC/C values (χ2=2.595, P=0.458) could be detected between IPCa, GH, SH and MH groups. The ADC values of the central gland only differed between IPCa (1.48±0.18) ×10-3 and GH (1.60±0.16) ×10-3 mm2/sec (P=0.037). The minimal ADC values were similar between IPCa (1.15±0.10) ×10-3 and BPH (1.14±0.11) ×10-3 mm2/sec, no significant differences could be detected between IPCa and GH (P=0.930), IPCa and SH (P=0.192), and IPCa and MH (P=0.544). Although the ADC values of the central gland of the prostate differed between IPCa and GH, the findings of the present study therefore indicate that combining 3D MRS with DWI cannot potentially improve the detection of IPCa.

Adrenal schwannoma: CT, MR manifestations and pathological correlation.

OBJECTIVES: This study aimed to describe the computed tomography (CT), magnetic resonance imaging (MRI) imaging features of adrenal schwannoma and to correlate imaging findings with histopathologic findings. METHODS: The findings from multiphase CT or MRI examinations of seventeen patients with histopathologically confirmed adrenal schwannoma were reviewed. The imaging criteria included shape, size, margin, attenuation, signal intensity, secondary degeneration, and internal mass enhancement pattern. RESULTS: All cases were unilateral, round or oval solitary tumors, with diameters ranging from approximately 2.5 to 8.8 cm (median = 4.5 cm). Of the twelve cases assessed using CT, adrenal schwannoma appeared as well-circumscribed round or oval low-density suprarenal masses with a mean attenuation values of 30.1 HU of solid portions during unenhanced phase. Ten cases exhibited heterogeneous cyst formation, and one case showed calcification. Internal septa were noted in 5 cases. All solid areas displayed early mild heterogeneous enhancement and delayed progressive enhancement. Regarding MRI, solid portions of five masses were hypointense to the liver parenchyma on T1-weighted imaging (T1WI) and were heterogeneously hyperintense on T2-weighted imaging (T2WI). The enhanced pattern of solid areas of adrenal schwannoma on MRI is similar to that of CT. Cystic or hemorrhagic changes were noted in 4 cases and internal septa were noted in 3 cases. CONCLUSION: Although schwannoma is a rare entity in the adrenal gland, we believe that the following signs may suggest the diagnosis of this entity: a non-lipid containing mass, a well-defined border, a unilateral mass with cystic or hemorrhagic degeneration, septa with delayed enhancement and a characteristic progressive contrast enhancement pattern of the solid portions.

Computed tomography perfusion and computed tomography angiography for prediction of clinical outcomes in ischemic stroke patients after thrombolysis.

Cerebral blood perfusion and cerebrovascular lesions are important factors that can affect the therapeutic efficacy of thrombolysis. At present, the majority of studies focus on assessing the accuracy of lesion location using imaging methods before treatment, with less attention to predictions of outcomes after thrombolysis. Thus, in the present study, we assessed the efficacy of combined computed tomography (CT) perfusion and CT angiography in predicting clinical outcomes after thrombolysis in ischemic stroke patients. The study included 52 patients who received both CT perfusion and CT angiography. Patients were grouped based on the following criteria to compare clinical outcomes: (1) thrombolytic and non-thrombolytic patients, (2) thrombolytic patients with CT angiography showing the presence or absence of a vascular stenosis, (3) thrombolytic patients with CT perfusion showing the presence or absence of hemodynamic mismatch, and (4) different CT angiography and CT perfusion results. Short-term outcome was assessed by the 24-hour National Institution of Health Stroke Scale score change. Long-term outcome was assessed by the 3-month modified Rankin Scale score. Of 52 ischemic stroke patients, 29 were treated with thrombolysis and exhibited improved short-term outcomes compared with those without thrombolysis treatment (23 patients). Patients with both vascular stenosis and blood flow mismatch (13 patients) exhibited the best short-term outcome, while there was no correlation of long-term outcome with CT angiography or CT perfusion findings. These data suggest that combined CT perfusion and CT angiography are useful for predicting short-term outcome, but not long-term outcome, after thrombolysis.

Early prediction of functional outcome using dynamic contrast enhanced magnetic resonance imaging in experimental stroke.

BACKGROUND AND PURPOSE: Early prediction of functional outcome in cerebral ischemia stroke using MRI remains a challenge. The aim of this study was to evaluate the predictive value of dynamic contrast-enhanced (DCE) MRI in terms of functional outcome of ischemia stroke. METHODS: Right middle cerebral artery occlusion (MCAO) was performed in male SD rats (n=50), followed by withdrawal of the occluding filament after 3 (n = 10), 4 (n = 10), 5 (n = 10), 6 (n = 10) or 7 (n = 10) h to establish ischemia and reperfusion stroke. DCE and conventional MRI were performed in each animal 60 ± 15 min before and after reperfusion. The outcome was assessed by the modified Neurological Severity Scores (mNSS) (before reperfusion and at 72 h after reperfusion) and the infarct volume. Comparisons of functional prognosis and DCE parameters (K(trans), Ve and Kep) were performed using binary logistic regression and operating characteristic (ROC) analysis. RESULTS: DCE parameters results indicated that blood brain barrier (BBB) permeability increased with prolonged reperfusion timing. Using binary logistic regression analysis on stroke characteristics (reperfusion timing, infarct volume) and BBB permeability parameters (drK(trans)subcortex, drK(trans)cortex, drVesubcortex, drVecortex, drKepsubcortex and drKepcortex) as covariates , the results demonstrated that reperfusion timing, infarct volume, drK(trans)subcortex and drKepsubcortex were independent factors that were associated with prognosis (OR=0.01, OR=0.23, OR=245.23, OR=1.29). ROC analysis indicated that a drK(trans)subcortex threshold of 0.88 with a sensitivity of 95.7% and a specificity of 85.2% and a drKepsubcortex threshold of -0.25 with a sensitivity of 69.6% and a specificity of 70.4% for differentiation between favourable and unfavourable prognosis. CONCLUSIONS: Quantitative DCE-MRI can be used to predict the functional outcomes of cerebral ischemia injury.

Computed tomography and magnetic resonance features of intracranial hemangioendothelioma: A study of 7 cases.

The current study aimed to present the neuroradiological and histopathological features of intracranial hemangioendothelioma (HE). The computed tomography (CT; n=3) and magnetic resonance imaging (MRI; n=7) features, and the clinical presentations of 7 patients with pathologically documented HEs were retrospectively analyzed. Lesions were observed in the right side of the skull (the frontal bone in 1 patient and the parietal bone in 1 patient), the tentorium (2 patients), the cerebral falx (1 patient), the right cavernous sinus (1 patient) and the right temporal lobe (1 patient). The tumor was lobulated in 5 cases and round in 2 cases. The majority of tumors appeared isointense or hypointense with multiple scattered hyperintensities on T1-weighted MRI. Moreover, the lesions appeared as inhomogeneous hyperintense regions with multiple enlarged and tortuous blood flow voids on T2-weighted MRI. The lesions also showed marked gadolinium enhancement in a honeycomb pattern. CT scan results showed a isoattenuation region (32-47 HU), with numerous small, round, high-density foci. The 2 cases with skull lesions presented with local bone destruction and discontinuous bone lines of the tabula interna ossis cranii. In 1 case, MR angiography revealed abnormal vessels in the basilar region. A total of 4 cases were epithelial HE, 2 were retiform HE and 1 was kaposiform HE. Histological examination revealed endothelial cell proliferation with vascular lesions and a mucous matrix or dense fibrous mesenchyme. In conclusion, intracranial HE is rare, but should be considered in the differential diagnosis when evaluating intracranial neoplasms. A well-defined lobulated mass and imaging features that include internal heterogeneity, small scattered hemorrhages and thromboses, signal voids of vessels, and marked and delayed enhancement may confirm the diagnosis of HE.

Prediction of Reperfusion-Associated Hemorrhagic Transformation Using Dynamic Contrast-Enhanced Imaging in a Rat Stroke Model.

BACKGROUND AND PURPOSE: Reperfusion-associated hemorrhagic transformation (HT) is an important complication of recanalization therapy. A method to identify stroke victims that may undergo HT will improve the patient selection and safety of this treatment. In this study, we determined the relationship between timing of reperfusion and the frequency and severity of HT, and whether very early dynamic contrast-enhanced (DCE) imaging predicts the occurrence of reperfusion-associated HT in a model of experimental stroke. METHODS: Intraluminal suture occlusion of the middle cerebral artery was used to produce transient ischemia in male Sprague Dawley rats (n = 50). Reperfusion was performed by withdrawal of the occluding filament after 3 (n = 10), 4 (n = 10), 5 (n = 10), 6 (n = 10), or 7 (n = 10) hours. Magnetic resonance imaging studies were performed before reperfusion using DCE, susceptibility-weighted imaging, diffusion-weighted imaging, and T2- and T1-weighted imaging. Follow-up magnetic resonance imaging and histological studies were performed at 24 hours. RESULTS: Hemorrhagic transformation occurred by 24 hours after injury in 8 of 50 animals. The HT rate increased with prolonged ischemic duration. All animals exhibiting acute blood-brain barrier (BBB) perturbation subsequently developed HT by 24 hours. Statistically significant differences in the BBB permeability parameters (P < 0.05) between the HT group and non-HT group were detected by DCE imaging. There were also statistically significant differences (P < 0.05) between the HT area and adjacent HT area. Among the permeability parameters, subcortex rK was the most sensitive and specific predictor of HT. CONCLUSIONS: The results suggest that the use of quantitative BBB measurements may further improve early prediction and identification of HT. The DCE parameters were the sensitive early independent predictor of reperfusion-associated HT.

CT features of retroperitoneal solitary fibrous tumor: report of three cases and review of the literature.

CT findings in three cases with solitary fibrous tumors (SFTs) confirmed by histopathology and immunohistochemistry were reviewed retrospectively, and compared with pathological results. The three tumors were large, well-defined, and smooth contour masses and SFT consisted of solid components of two different densities. On enhanced CT scans, tumors were strongly enhancing, the multiple vascular shadows were seen within the tumor in the arterial phase. There is progressive enhancement from the arterial to the venous phase, and the tumor capsule can be observed. Histologically, the tumors are composed of spindle cells within a background of collagen stroma, and showed a wide range of growth patterns, alternating hypercellular (tumor cell-rich) and hypocellular (collagen-rich) areas. The diagnosis is confirmed by characteristic positive immunohistochemical staining for CD34.

Magnetic resonance imaging findings of intracranial papillary meningioma: a study on eight cases.

OBJECTIVES: To increase the awareness on intracranial papillary meningiomas (PMs) by presenting magnetic resonance imaging (MRI) findings on this disease. MATERIALS AND METHODS: The MRI findings and clinical presentations of nine discrete lesions in eight patients with pathologically documented PMs were retrospectively analyzed. RESULTS: Most tumors occurred in young adults. The tumors originated from the convexity meninges in five cases and from the parasagittal regions in four cases. The tumor shape was irregular in six cases, lobulated in two cases, and round in one case. By MRI, nine masses were primarily isointense (n=5) or mildly hypointense (n=4) to gray matter on T1-weighted images and inhomogeneous hyperintense (n=3) or isointense (n=6) to the cortex on T2-weighted and fluid-attenuated inversion recovery images. On diffusion-weighted imaging, the signal intensity of the tumor was increased in all lesions compared with the adjacent parenchyma. Tumor and brain interfaces were unclear in seven cases, cyst formation was observed in eight tumors, scattered hemorrhage was observed in three tumors, signal voids due to vessels were visible in four cases, and eight tumors had moderate or marked irregular peritumoral edema. Enhancement was homogeneous (n=2) or heterogeneous (n=7), an area of focal nodular enhancement was observed in three lesions, and the dural tail sign was visible in seven cases. CONCLUSION: Although PM is rare, it should be considered in the differential diagnosis when evaluating intracranial neoplasms. Younger patient age, as well as imaging features such as unclear tumor-brain interface, internal heterogeneity including cyst formation, irregular enhancement, signal voids of vessels, and marked peritumoral edema can help distinguish PM from typical benign meningiomas.

Comparison of three-dimensional negative-contrast CT cholangiopancreatography with three-dimensional MR cholangiopancreatography for the diagnosis of obstructive biliary diseases.

PURPOSE: The purpose of our study was to compare three-dimensional (3D) negative-contrast CT cholangiopancreatography (3D-nCTCP) with 3D MR cholangiopancreatography (3D-MRCP) for the diagnosis of obstructive biliary diseases. MATERIALS AND METHODS: 3D-nCTCP and 3D-MRCP were performed on seventy clinically documented obstructive biliary diseases patients. The accuracy of each technique in determining the location and cause of biliary obstruction was evaluated compared with the final clinical diagnoses. RESULTS: Both methods achieved 100% of accuracy in the diagnosis of the presence and location of biliary obstruction, and had a similar sensitivity, specificity, accuracy in differentiating benign from malignant biliary obstruction or calculous from noncalculous biliary obstruction (p>0.05). At 3D-nCTCP, six patients with stones were misinterpreted as cholangitis (N=2), papillitis (N=3), or bile duct adenocarcinoma (N=1); two metastases were mistaken as acute pancreatitis or pancreatic head carcinomas, and one intrahepatic cholangiocarcinoma was misled as bile duct adenoma. At 3D-MRCP, one small stone, one ampullary adenoma, and one intrahepatic cholangiocarcinoma were mistaken as cholangitis, ampullary stone, and intrahepatic bile duct stone, respectively, and three gallbladder carcinomas and another intrahepatic cholangiocarcinoma were misdiagnosed as hilar cholangiocarcinoma (N=3) or common hepatic duct stone (N=1); four metastases were mistaken as pancreatic head carcinomas (N=3) or distal cholangiocarcinoma (N=1). The overall accuracy in making specific diagnosis of the cause of biliary obstruction was 87.1% for 3D-nCTCP and 84.3% for 3D-MRCP, respectively, (p>0.05). CONCLUSION: 3D-nCTCP has the similar effects as 3D-MRCP for the diagnosis of biliary obstruction and, the location and the cause of biliary obstruction. In view of selected cases contraindications for MRI, 3D-nCTCP is a potential substitute.