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Imaging studies are a major component in the evaluation of patients for the screening, staging and surveillance of colorectal cancer. This review presents commonly encountered findings in the diagnosis and staging of patients with colorectal cancer using computed tomography (CT) colonography, magnetic resonance imaging (MRI), and positron emission tomography (PET)/CT colonography. CT colonography provides important information for the preoperative assessment of T staging. Wall deformities are associated with muscular or subserosal invasion. Lymph node metastases from colorectal cancer often present with calcifications. CT is superior to detect calcified metastases. Three-dimensional CT to image the vascular anatomy facilitates laparoscopic surgery. T staging of rectal cancer by MRI is an established modality because MRI can diagnose rectal wall laminar structure. N staging in patients with colorectal cancer is still challenging using any imaging modality. MRI is more accurate than CT for the evaluation of liver metastases. PET/CT colonography is valuable in the evaluation of extra-colonic and hepatic disease. PET/CT colonography is useful for obstructing colorectal cancers that cannot be traversed colonoscopically. PET/CT colonography is able to localize synchronous colon cancers proximal to the obstruction precisely. However, there is no definite evidence to support the routine clinical use of PET/CT colonography.

Purpose: This study describes a quantitative method to estimate the migratory capacity of neural stem cells (NSCs) using magnetic resonance imaging., Procedures: NSCs were labeled with ferumoxides and injected stereotaxically into the corpus callosum of the normal rat brain. Control subjects received either free ferumoxides or nonviable labeled cells. Subjects were scanned after initial injection and at 1 week. Image sets were coregistered, compared morphologically, and analyzed parametrically to determine migration speed., Results: Subjects receiving injections of viable cells had a significantly greater spread of the tracer after 1 week than either control group (p< 0.05). The speed of migration for viable NSCs was significantly higher than that of controls along the corpus callosum (p < 0.05). Migratory speeds estimated from histology and imaging were significantly correlated., Conclusions: This study provides a quantitative assessment of posttransplantation neural stem cell migration that is clearly distinguishable from tracer clearance.

Isolated fourth ventricle is a rare complication following shunt insertion of the lateral ventricles for hydrocephalus. The present report describes a rare case of a hemangioblastoma of the medulla oblongata that caused isolated fourth ventricle due to intraventricular deposition of fibrin. A 34-year-old man presented with headache a month before admission. Magnetic resonance imaging indicated multiple tumors in the medulla oblongata and the bilateral cerebellar hemisphere with surrounding edema, and the patient was diagnosed with hemangioblastoma. The patient began to develop progressive headache and nausea after stereotactic radiosurgery, and computed tomography showed obstructive hydrocephalus. Endoscopic third ventriculostomy was performed, and the intraoperative view of this showed that the walls of the lateral and third ventricles were covered with a white membrane-like substance. Endoscopic third ventriculostomy and then ventriculoperitoneal shunt did not improve the hydrocephalus. The patient's consciousness deteriorated due to isolated fourth ventricle and upward herniation. The patient underwent posterior fossa craniotomy and the tumor in the medulla oblongata was removed via a telovelar approach. Intraoperatively, the fourth ventricle was filled with a white membrane-like substance, which was surgically removed and pathologically diagnosed as fibrin. The patient's consciousness and obstructive hydrocephalus improved after surgery. The present case suggests that isolated fourth ventricle may occur after VP shunt placement for the hydrocephalus with hyperproteinorachia. [ABSTRACT FROM AUTHOR]

We attempted to establish a magnetic resonance imaging (MRI)-based radiomic model for stratifying prognostic subgroups of newly diagnosed glioblastoma (GBM) patients and predicting O (6)-methylguanine-DNA methyltransferase promotor methylation (pMGMT-met) status of the tumor. Preoperative MRI scans from 201 newly diagnosed GBM patients were included in this study. A total of 489 texture features including the first-order feature, second-order features from 162 datasets, and location data from 182 datasets were collected. Supervised principal component analysis was used for prognostication and predictive modeling for pMGMT-met status was performed based on least absolute shrinkage and selection operator regression. 22 radiomic features that were correlated with prognosis were used to successfully stratify patients into high-risk and low-risk groups (p = 0.004, Log-rank test). The radiomic high- and low-risk stratification and pMGMT status were independent prognostic factors. As a matter of fact, predictive accuracy of the pMGMT methylation status was 67% when modeled by two significant radiomic features. A significant survival difference was observed among the combined high-risk group, combined intermediate-risk group (this group consists of radiomic low risk and pMGMT-unmet or radiomic high risk and pMGMT-met), and combined low-risk group (p = 0.0003, Log-rank test). Radiomics can be used to build a prognostic score for stratifying high- and low-risk GBM, which was an independent prognostic factor from pMGMT methylation status. On the other hand, predictive accuracy of the pMGMT methylation status by radiomic analysis was insufficient for practical use. [ABSTRACT FROM AUTHOR]

The article presents a case study of an 83-year-old Japanese man who was admitted for an acute onset of right hemichorea. An imaging study showed a reduced rate of cerebral glucose metabolism on positron-emission tomography and hyperperfusion on single-photon emission computed tomography (SPECT) showed suggesting the subsequent regional metabolic failure.