The palatovaginal canal: can it be identified on routine CT and MR imaging?

OBJECTIVE: The palatovaginal canal is a short bone tunnel that extends from the pterygopalatine fossa to the roof of the pharynx. The primary purpose of our work was to establish whether the palatovaginal canal can be identified on CT and MR imaging. The secondary goal was to establish the frequency of visualization and the appearance of this canal. MATERIALS AND METHODS: We retrospectively analyzed 150 consecutive direct coronal CT studies obtained for evaluation of the sinonasal cavities. Frequency, bilaterality, and appearance of the palatovaginal canals were recorded. The frequency of the vidian canals was recorded for comparison. We also analyzed 20 MR imaging studies of that area to assess visualization of the palatovaginal canals and their contents. A dry skull specimen was examined using CT, and the images were correlated with those obtained in vivo. RESULTS: The palatovaginal canal could be identified on CT on at least one side in 88 (58.7%) of 150 patients. Unilateral complete canals were found in 14 patients (9.3%), and unilateral semicanals were evident in 17 (11.3%). Bilateral complete canals were seen in 24 patients (16%), and bilateral semicanals were found in 11 (7.3%). In 22 patients (14.7%), one complete canal and one semicanal were detected. Fifty-five percent of the visualized canals were completely formed. The palatovaginal canal and its internal tubular structure, presumably corresponding to the pterygovaginal artery, were depicted on 40% of the MR imaging studies. The position and configuration of this canal as seen on CT of the dry skull specimen correlated well with the imaging findings. CONCLUSION: The palatovaginal canals are commonly depicted on CT and MR imaging.     

Airway and ventilatory equipment in field anesthesia: what's new?

Advances in medical technology provide the modern day field anesthetist with the extra edge to meet the challenges faced in the harsh environment of the battlefield and enhance the survivability of casualties. The tasks of triage, resuscitation, and administration of anesthesia can be facilitated with the use of new airway devices, portable ventilators, and monitoring devices. Before such equipment is used in the field, the anesthetist must carefully weigh the advantages and disadvantages and must be cognizant of the limitations of individual devices in different environmental settings. These devices should ideally be portable, lightweight, rugged in construction, durable, easy to use (requiring minimal training and supervision), readily replaceable, and cost-effective.     

Pneumobilia: where to look for on hepatic MR imaging?

The presence of pneumobilia is a particular problem in magnetic resonance cholangiopancreatography (MRPC) and may create an appearance that can be mistaken for intraductal stones. Compared with biliary stones, however, pneumobilia causes a susceptibility artifact on hepatic MR imaging and appears as a signal void on a dual echo gradient MR sequence, such as the T1-weighted in-phase and opposed-phase gradient echo sequence. This susceptibility artifact is more pronounced on the gradient echo image with the longer echo time due to the continued decay of the transverse magnetization. Besides identification of hepatic steatosis, the double echo approach is particularly helpful in identification of pneumobilia.     

Primary nasopharyngeal non-Hodgkin’s lymphoma: imaging patterns on MR imaging

ObjectivesTo summarize the distinct imaging features of different subtypes of primary nasopharyngeal non-Hodgkin's lymphomas (NHLs).Materials and methodsClinical data and magnetic resonance imaging findings of 71 patients with histologically proven primary nasopharyngeal NHLs were retrospectively reviewed. The tumor distribution, signal intensity, lesion texture, contrast enhancement properties, extra-chamber involvement, regional structure invasion, and cervical lymphadenopathy were evaluated and compared between different subtypes of NHLs.ResultsOf the patients, 70.4% had B-cell lymphomas; 64.8% had symmetrical and diffuse involvement of nasopharynx walls; and 19.7% had superficial ulcerations. Extra-chamber involvement and regional structure invasion occurred in most patients. The frequency of neck node involvement was up to 83.10%; 62.7% of them were bilateral involvement. Patients with T-cell or nature killer/T-cell NHLs had a higher incidence of superficial ulcerations, nasal cavity, and paranasal sinus invasion than B-cell NHLs (P< .05). Patients with B-cell NHLs had a higher incidence of cervical lymphadenopathy specifically in Level VA and parotid region than T-cell or nature killer/T-cell (NK/T-cell) NHLs (P< .05).ConclusionPrimary nasopharyngeal NHLs had some characteristic imaging features and different subtypes of nasopharyngeal NHLs had some distinct imaging features.     

CT colonography: where have we been and where are we going?

Over the past decade, computed tomographic (CT) colonography (also known as virtual colonoscopy) has been used to investigate the colon for colorectal neoplasia. Numerous clinical and technical advances have allowed CT colonography to advance slowly from a research tool to a viable option for colorectal cancer screening. However, substantial controversy remains among radiologists, gastroenterologists, and other clinicians with regard to the current role of CT colonography in clinical practice. On the one hand, all agree there is much excitement about a noninvasive imaging examination that can reliably depict clinically important colorectal lesions. However, this is tempered by results from several recent studies that show the sensitivity of CT colonography may not be as great when performed and the images interpreted by radiologists without expertise and training. The potential to miss important lesions exists; moreover, if polyps cannot be differentiated from folds and residual fecal matter, unnecessary colonoscopy will be performed. In this review, current issues will be discussed regarding colon cancer and the established and reimbursed strategies to screen for it and the past, current, and potential future role of CT colonography.     

Atretic parietal cephaloceles revisited: an enlarging clinical and imaging spectrum?

PURPOSEWe describe imaging features that are clues to the diagnosis of atretic cephaloceles and discuss clinical findings and a possible mechanism by which these lesions develop.METHODSEight children (five girls and three boys) ranging in age from 1 day to 3 years 4 months with midline subscalp lesions underwent radiologic examination with CT or MR imaging. In all cases, the lesions were surgically excised and subjected to pathologic examination. Imaging studies and medical records were reviewed retrospectively.RESULTSSix of eight children had vertical embryonic positioning of the straight sinus with a prominent superior cerebellar cistern. A "spinning-top" configuration of the tentorial incisura, a "cigar-shaped" CSF tract within the interhemispheric fissure, fenestration of the superior sagittal sinus, and "peaking" of the tentorium were associated findings helpful in making this diagnosis. Two of the eight children had findings indistinguishable from focal dermoid, six were developmentally normal, one had mild motor delay, and one died at the age of 3 years. Pathologic examination revealed glial, meningeal (arachnoid), fibrous, and dermal elements.CONCLUSIONCharacteristic findings on MR images and CT scans provide clues to the diagnosis of atretic cephalocele. However, even in the presence of abnormal imaging findings, these children may be developmentally normal.     

Incidental liver lesions seen on Breast MRI: When is additional imaging warranted?

PurposeIncidental hepatic lesions identified on breast MR can be a diagnostic dilemma due to concern for liver metastases or other significant hepatic lesions. The purpose of this study was to identify the incidence and nature of liver lesions seen on breast MR, and determine if additional imaging is necessary.Methods and materialsImaging reports of all breast MR examinations performed at our institution from January 1, 2010 to December 31, 2011 were reviewed to identify reports with hepatic abnormalities. Lesion characteristics, subsequent diagnosis, duration of follow up and additional imaging results (if performed) were all recorded.ResultsOf 1664 breast MRs, incidental hepatic lesions were seen in 207 studies (12.4%) in 169 patients. In 154 of 169 patients (91.1%) the lesions were characterized as T2 hyperintense and clearly as bright as adjacent fat on T2-weighted or localizer sequences. 0 of these 154 lesions were clinically significant at clinical or radiological follow-up. In the remaining 8.9% (15 of 169), lesions were characterized as not as bright as adjacent fat on T2 weighted or localizer imaging. In two cases, lesions were confirmed as incidental hepatic metastatic disease.Conclusion91.1% of incidental hepatic lesions were circumscribed, T2 hyperintense lesions and characterised as clearly as bright as adjacent fat on T2 weighted imaging at additional review. None of which were clinically significant at clinical or radiological follow-up. We advocate that circumscribed T2 hyperintense lesions which are clearly as bright as adjacent fat on T2 weighted imaging are of unlikely clinical significance and follow-up imaging should not be recommended, reducing the rate of additional imaging from 37.3% to 5.3%.     

Feng Chen’s work on translational and clinical imaging

Dr. Feng Chen is a chief medical doctor and the vice chairman of the Department of Radiology in Zhong Da Hospital at Southeast University, Nanjing, China and a senior researcher in the Department of Radiology at the Catholic University of Leuven, Belgium. His main areas of interest are translational imaging research including stroke, tumor angiogenesis, assessment of therapeutic response in solid tumors, and magnetic resonance contrast media. Dr. Feng Chen has published 44 scientific papers in peer-reviewed international journals. He and his colleagues have developed an imaging platform which includes animal models, animal preparations and multiparametric magnetic resonance imaging (MRI) protocols for translational animal imaging research using clinical machines. His MRI findings on rodent stroke are considered to "serve as a model for future laboratory investigations of treatment of acutestroke and unify the approaches developed for clinical studies". He and his colleagues have introduced a novel liver tumor model in rodents, in which a series of studies concerning the antitumor activity of vascular disrupting agents have been successively conducted and assessed by in vivo MRI, especially by diffusion weighted imaging as an imaging biomarker. His goal is to provide valuable references for clinical practice and to contribute to the translation of animal imaging research into patient applications.