Feasibility of MR imaging in evaluating breast cancer lymphangiogenesis using Polyethylene glycol-GoldMag nanoparticles.

AIM: To investigate the feasibility of evaluating tumour lymphangiogenesis using magnetic resonance imaging (MRI) in vivo. MATERIALS AND METHODS: Water-soluble polyethylene glycol (PEG)-GoldMag nanoparticles were obtained by combining GoldMag with PEG. The PEG-GoldMag nanoparticles were bound to anti-podoplanin antibody (PodAb) to construct PEG-GoldMag-pod molecular probes targeting lymphatic endothelial cells (LECs). The characteristics of the PEG-GoldMag-pod nanoparticles were tested. Using these nanoparticles, tumour lymphangiogenesis was evaluated using MRI in vitro and in vivo. RESULTS: The average size of PEG-GoldMag nanoparticles was about 66.8 nm, and the nanoparticles were stably dispersed in the liquid phase for at least 15 days. After incubation for 24 h at different iron concentrations ranging from 5-45 µg/ml, the LECs were labelled with PEG-GoldMag-pod nanoparticles, in particular the breast cancer LECs. Dose-dependence was observed in the labelling efficiencies and MRI images of the labelled cells. In vitro, the labelling efficiencies and MRI images showed that the nanoparticles could detect podoplanin expression in LECs. In induced rat models of breast cancer, PEG-GoldMag-pod nanoparticles combined with lymphatic vessels were significantly detectable at MRI 60 min after nanoparticle administration, the signal intensity was negatively correlated with the lymphatic vessel density of breast cancer (r = -0.864, P = 0.000). CONCLUSIONS: The present study proves the feasibility of evaluating tumour lymphangiogenesis with MRI in vivo.

Rathke's cleft cyst: clinicopathological and MRI findings in 22 patients.

AIM: To evaluate clinical findings and magnetic resonance imaging (MRI) characteristics of Rathke's cleft cyst (RCC) in 22 patients. MATERIALS AND METHODS: Twenty-two patients were imaged using non-enhanced MRI and 17 underwent an additional contrast-enhanced MRI examination. Fifteen patients received an additional non-enhanced computed tomography (CT) examination, and amongst these, two underwent contrast-enhanced CT. Two radiologists read the images retrospectively. The imaging data were studied with regards to location, size, margin, signal intensity, enhancement characteristics, haemorrhage, and presence of calcifications. Clinical data, such as presenting signs and symptoms, physical findings, and medical histories, were collected. Histopathological studies were performed and analysed by two pathologists. RESULTS: Nine lesions were located in the intrasellar region, 12 in both the intra- and suprasellar regions and one in the suprasellar region. The maximum diameter of the RCCs varied from 0.7 to 4 cm, with an average size of 1.7+/-0.7 cm. MRI features of RCC were divided into three groups based on T1-weighted imaging (T1WI): hypo- (n=6), iso- (n=9), and hyperintensity group (n=7). Patients in the latter two groups were statistically younger than that in the former group. The lesion size in the iso- and hyperintensity groups was significantly less than that in the hypointensity group (F=6.421, p=0.007). Only two cases showed enhancement after contrast injection in the cohort. One lesion with haemorrhage was found as were two cases with intracystic nodules. CONCLUSION: Although MRI features of RCCs are variable, RCCs should be suspected when the following conditions occur: lesions located in the intrasellar region or involving both intra and suprasellar regions, less than 1.5 cm in diameter, iso- or hyperdense on T1WI and no signal enhancement after contrast injection. In addition, the first case of a RCC with a markedly enhanced intracystic nodule is reported.

MRI findings of intracranial cystic meningiomas.

AIM: To report the magnetic resonance imaging (MRI) features of intracranial cystic meningiomas and compare these features in intra- and peritumoural cyst groups. MATERIALS AND METHODS: Fourteen cases of peritumoural cystic meningiomas were compared with 18 cases of intratumoural cystic meningiomas. All patients were examined using non-enhanced and contrast-enhanced MRI. Tumour location, tumour size, signal intensity, enhancement characteristics, and cystic changes were assessed. The MRI features were compared between the intra- and peritumoural cyst groups. RESULTS: Most cystic meningiomas comprised two or more cysts. The solid parts of the tumours showed moderate or marked enhancement after the injection of contrast material. An enhanced cyst wall was found in six out of 14 cases in the peritumoural cyst group, but not in the intratumoural cyst group. Peritumoural cystic meningiomas were predominately located in the cerebral falx, whereas the intratumoural cystic meningiomas were predominantly found in frontal convexity (X(2)=7.434, p=0.024). The cysts were larger in the peritumoural cyst group than in the intratumoural cyst group (t=5.274, p=0.0258). Peritumoural oedema was more commonly found in the intratumoural cyst group (X(2)=6.863, p=0.008). Cystic meningiomas with solid parts located inside the cyst are reported for the first time. CONCLUSION: Cystic meningiomas, although uncommon, should be differentiated from other cystic intracranial lesions. Peri- and intratumoural cystic meningiomas have distinct MRI features. The present study provides the first report of two lesions with solid parts located inside the cyst, as well as one lesion with a calcified solid nodule and haemorrhage within the cyst.

Intracranial ganglioglioma: clinicopathological and MRI findings in 16 patients.

AIM: To record the clinical findings and magnetic resonance imaging (MRI) characteristics of intracranial gangliogliomas in 16 patients. MATERIALS AND METHODS: Sixteen patients were imaged using unenhanced and contrast-enhanced MRI. Eight patients underwent unenhanced CT and of these, three underwent contrast-enhanced CT. Two radiologists read the images retrospectively. The images were studied with regard to location, size, margin, signal intensity, enhancement characteristics, cystic changes, and presence of calcifications. Clinical data, such as presenting signs and symptoms, physical findings, and medical histories, were collected. Histopathological and immunohistochemical studies were performed and analysed by two pathologists. RESULTS: In 12 cases the tumours were located in one of the cerebral hemispheres; in the other cases they were located in the brainstem, cerebellum, suprasellar area or the thalamus. The tumour dimension varied from 1-7 cm, with a mean of 3.6 cm+/-1.8 cm. The MRI features of ganglioglioma in the present cohort can be divided into three patterns: cystic (n=2), cystic-solid (n=6), and solid (n=8). Solid lesions had a predilection for the temporal lobe; cystic and cystic-solid tumours had a wide anatomical distribution. Cystic lesions were significantly smaller than both cystic-solid and solid lesions (F=4.28, P<0.05). Cystic changes in the cystic-solid tumours showed one of the following patterns: those with walls showing contrast enhancement, those containing an enhancing nodule, or cysts without an obvious wall. The solid portion of cystic-solid gangliogliomas and the entire tumour in solid tumours showed homogeneous enhancement of variable degrees on T1-weighted (T1W) spin-echo (SE) images. Five tumours had mild or moderate oedema. In one patient two separate gangliogliomas were found, each lesion exhibiting different MRI features: solid and cystic-solid. One case of cortical ganglioglioma was found, causing bone erosion due to pressure. One tumour with chronic haemorrhage was found in the study. CONCLUSION: MRI features of gangliogliomas are non-specific. A ganglioglioma should be suspected when a tumour shows the following features: (1) a solid lesion located in the temporal lobes with mild or no oedema and homogeneous enhancement on SE T1W images; or (2) a small cystic lesion or cystic-solid mixed mass with a wall enhancement or a markedly enhanced nodule. We report a patient with two separate gangliogliomas and a case with bone erosion.

Central neurocytoma: clinical, pathological and neuroradiological findings.

AIM: To evaluate the clinical, pathological and neuroradiological features of intraventricular central neurocytoma in six patients. MATERIALS AND METHODS: Six patients were imaged using non-enhanced and contrast-enhanced magnetic resonance imaging (MRI); three of them were also examined using non-enhanced computed tomography (CT). Two radiologists read the images retrospectively. The imaging data were studied with regard to location, size, margin, signal intensity, enhancement characteristics and presence of calcifications. Clinical data (i.e. presenting signs and symptoms, physical findings and medical histories) were collected and histopathological and immunohistochemical studies were performed by two pathologists. RESULTS: All lesions were located in the lateral ventricles. Three tumors were confined to the left side, one to the right side and two cases involved both lateral ventricles. The growth of central neurocytoma was of close spatial relation to the septum pellucidum. On MRI, most of the cases showed a heterogeneous hypointensity on T1-weighted images and hyperintensity on T2-weighted images or FLAIR with a well-defined margin. The presence of cystic components, necroses and calcifications caused these internal heterogeneities. After intravenous administration of gadolinium (Gd-DTPA) all tumours showed a heterogeneous enhancement. CT provided additional information by distinguishing intratumoural calcifications in all three evaluated cases. Immunohistochemical analysis showed positive synaptophysin staining in all cases and positive neuron-specific enolase staining in four cases. In three cases a small proportion of the tumour cells could be labelled with antibodies to glial fibrillary acid protein (GFAP). CONCLUSION: Central neurocytoma should be considered when the following conditions occur: young patients with lesions in the lateral ventricle, which contain calcifications and show some enhancement. This is especially applicable for tumours involving both lateral ventricles with symmetrical growth around the centre of septum pellucidum or for unilateral ventricular tumors with a wide base attachment to the septum pellucidum.