Physical examination showed no chemosis, vision loss or cranial nerve palsies.  Because of this the patient was brought back for repeat contrast enhanced CT of the orbits with Valsalva maneuver.  This study showed mild additional enlargement of the already prominent left superior ophthalmic vein and also of the right sided one (see below).  The combination of imaging and clinical findings was thought to be most compatible with orbital varices.  The patient opted for conservative management.

Orbital varices are hamartomas composed of slow flow, low pressure and thinned walled and distensible blood vessels.  As they communicate with the rest of the circulation, they enlarge with Valsava, bending or prone position, and coughing and straining.  They produce proptosis which may be painful and because they may bleed, their symptoms may become acutely exacerbated.  They may also erode adjacent bone.  Treatment is very difficult and is reserved for those with repeated hemorrhages, thrombosis, optic nerve compression and disfigurement.  Orbital vascular processes included in the differential diagnosis are carotid cavernous fistulas of both types and less likely, venous thrombosis.

In CC fistulas, the ipsilateral cavernous sinus may be enlarged particularly in the direct ones (see below).  Extra-ocular muscles may also be large and the retro-ocular fat may have a “dirty” appearance.  In most patients with direct CCFs, chemosis, decreased vision and cranial nerve palsies are present.  Acute thrombosis of the superior ophthalmic vein may present with symptoms that are similar to those of a direct CCF.  Indirect CCFs may have less acute symptoms and be clinically similar to varices.  The diagnosis is confirmed with catheter angiography as shown here.

Suggested readings:

YO Arat, ME Mawad, M Boniuk. Orbital Venous Malformations: Current Multidisciplinary Treatment Approach. Arch Ophthalmol 2004; 122: 1151 – 1158

N Islam, K Mireskandari, GE Rose. Orbital varices and orbital wall defects. Br J Ophthalmol 2004; 88: 1092 – 1093

A Weill, C Cognard, L Castaings, G Robert, J Moret. Embolization of an orbital varix after surgical exposure. AJNR Am. J. Neuroradiol. 1998; 19: 921 – 923

The quantification of the perfusion parameters in neck cancer is valuable as the quantitative results may facilitate an objective disease monitoring in the same institution and, under certain circumstances, an interchangeability across different institutions. Nowadays, theoretical models deliver quantitative information (of course under certain inevitable assumptions concerning the relationship between MR signal and contrast agent concentration) which are obviously superior to heuristic (semi-quantitative) DCE parameters, such as peak enhancement, maximum upslope, time-to-peak enhancement, and washout slope. In the future, DCE-MRI should be besides CT a major player in this field and combined with diffusion-weighted sequences and spectroscopy may face equally the PET/CT.

Kim et al. focused on the nodal disease, which is a rather unattended aspect in the DCE imaging of neck cancer. The authors found significantly elevated baseline Ktrans in responders, which presumably has led to a better distribution of the chemotherapeutics than in the non-responders who had lower Ktrans values. This seems logical but on the other hand we should bear in mind that high Ktrans may imply severe neoangiogenesis, which, in turn, implies a more aggressive tumor with possibly higher microvascular density. Lower Ktrans may also be the result of necrotic areas thus, poor oxygenation and poor response to radiotherapy. Apparently, the interpretation of the microcirculatory parameters should not be one-sided and in a concomitant chemoradiation setting is definitely difficult to separate the effects of each therapy and draw easily logical conclusions. The authors could not demonstrate except of any significant association between ve, τi and response to therapy. This is not necessarily a drawback of the method but may reflect the heterogeneity of the volume of the target node as well as the different induction chemotherapy regimens across the patients. In a point of view what actually play the most important role are not the baseline microcirculatory parameter values themselves but how they shift during the therapy and after its completion. Obviously, the nodal and tumor response to therapy may have different time points, which are crucial for the further treatment planning. As expected, patients with small nodes in the present study [1] were complete responders after the preoperative chemoradiation, however, some of them had distant metastasis after 6 months. In other words, the 6-month follow-up is more reliable time point for deciding the predictive value of the DCE-imaging parameters. Furthermore, Kim et al. by demonstrating the feasibility of their method posed a very important question: how shall we analyse the nodal disease by means of DCE-MRI? Shall we calculate the microcirculation parameters on a single target node, on a node-to-node basis, or shall we average them?

The results in the presented paper are initial and in a small patient population, thus, far from drawing definite thresholds, cut-off values and significant predictive parameters. Ideally, the work of Kim et al. should trigger DCE-MRI studies that would: 1) compare the microcirculation parameters of histologically confirmed metastatic and reactive lymph nodes, 2) investigate the alteration of microcirculation parameters during the course of chemoradiation, defining the optimal time points for monitoring, and 3) compare the microcirculation parameters of tumoral and nodal residual disease/recurrence and chemoradiated neck tissue. Only under these premises, we would be able to use DCE-MR imaging as a diagnostic clinical tool and, thus, estimate the real predictive value of the microcirculation parameters.

References:

1. Kim S, Loevner LA, Quon H, Kilger A, Sherman E, Weinstein G, Chalian A, Poptani H. Prediction of Response to Chemoradiation Therapy in Squamous Cell Carcinomas of the Head and Neck Using Dynamic Contrast-Enhanced MR Imaging. AJNR Am J Neuroradiol. 2009 Oct 1. [Epub ahead of print]
2. Cao Y, Popovtzer A, Li D, Chepeha DB, Moyer JS, Prince ME, Worden F, Teknos T, Bradford C, Mukherji SK, Eisbruch A. Early prediction of outcome in advanced head-and-neck cancer based on tumor blood volume alterations during therapy: a prospective study. Int J Radiat Oncol Biol Phys. 2008;72:1287-90.
3. Bisdas S, Baghi M, Wagenblast J, Vogl TJ, Thng CH, Koh TS. Gadolinium-enhanced echo-planar T2-weighted MRI of tumors in the extracranial head and neck: feasibility study and preliminary results using a distributed-parameter tracer kinetic analysis. J Magn Reson Imaging. 2008;27:963-9.

You may have heard that Propanolol is currently being used as treatment for some infantile hemangiomas of both types (RICH and NICH).  In this presentation prepared for our weekly case conference by Mr. Danilo Bernardo the results of such therapy are illustrated and discussed.

Has anyone an explanation for the focal bright spot on T1-weighted images in the cranial portion of the pituitary stalk, just down the median eminence, in the presence of a normal neurohypophysis?

Is it an “ectopic” adenohypophysis?

Is this a thin pituitary stalk in pituitary gland hypoplasia?

What will happen at follow-up?

It is  the start of  an infiltrative disease?

…It is simply that I do not know the normal and physiological behavior of the pituitary gland?…

Best regards to all of You!

The authors state that “CT is still the method of choice for detecting intraocular calcium and investigating orbital pathologies”, but support this with articles from 1997 and 1999. At CHOP, we have virtually eliminated the use of CT in our patients presenting with suspected retinoblastoma, and for follow up of treated patients. Have we all just changed our approach and not documented it very well in the literature?

As fewer enucleations are performed, in favor of eye-sparing procedures, it is increasingly important that all of the orbital structures be accurately assessed for residual and recurrent disease. In the same setting as the orbit MRI, brain MRI can assess for intracranial lesions. The ophthalmologic examination can often be coordinated to precede or follow the MRI, with the same sedation or anesthesia, as most affected are young children.

Anyone out there still routinely using CT for retinoblastoma?

Fluid-fluid levels are the result of mucinous areas or microcysts, or as a result of necrosis and hemorrhage. The fluid is unclotted blood against serous fluid. In addition, in areas of necrosis, the fluid that fills a necrotic cavity early on tends to be more proteinaceous than newer interstitial fluid. In such cases, fluid separation, based on viscosity and protein content, may occur. When fluid levels are seen in masses arising from nerves, schwannoma should first on the differential diagnosis.

We would like to know if anyone has had a similar experience with intracranial schwannomas.

H. Kato, et al. Fluid-Fluid Level Formation: A Rare Finding of Extracranial Head and Neck Schwannomas. AJNR Am J Neuroradiol 2009 0: ajnr.A1511.

In a technical note entitled “Window Settings for the Study of Calcified Carotid Plaques with Multidetector CT Angiography”, Drs. L. Saba and G. Mallarini evaluated how neuroradiologists who are reviewing CT-angiograms of the carotid arteries tend to spontaneously adjust their selection of CT window level and width, in order to accurately quantify the degree of carotid stenosis. They observed that, in the presence of calcified carotid plaques, the window width and level selected by the reviewers were not influenced by the degree of stenosis, but rather increased proportionally to the intraluminal Hounsfield unit value. Indeed, in the presence of a successful contrast bolus, the density of the intraarterial contrast comes closer to that of calcium, and a higher level and wider window are needed to decrease the “edge blur” and the “halo” artifacts, and to allow accurate quantification of the carotid stenosis.

It is interesting to note that the interobserver agreement in terms of characterizing the degree of carotid stenosis was extremely high in this study, superior to 90%. This high interobserver agreement was not the result of specific reading instructions, as the reviewers were not provided any, but were free to select their windowing and reading approach. Their experience prompted them to choose similar approaches and contributed to  their making the same measurements. This is a testament to the reliability of CT-angiography technique  in assessing carotid atherosclerotic disease in experienced hands. This technical note adds to a series of papers showing that carotid CT-angiography is accurate in quantifying carotid stenosis, (1, 2) is relevant in terms of clinical management; (3) and is a non-invasive alternative of choice to conventional angiography for screening purposes.(1) This is something that neuroradiologists want to emphasize and explain to justify the 200% increase in utilization of this technique over the past couple of years the latter raising concern on the side of the healthcare reimbursement entities, and leading them to question the validity of CT-angiography as compared to conventional angiography.

Further improvements in terms of CT assessment of carotid atherosclerotic plaques are expected with the generalization of dual-energy CT, which should allow to better characterize carotid plaque themselves, like they do for coronary arteries (4). Assessing atherosclerotic plaques themselves (rather than their mere impact on the lumen) holds great promises in terms of identifying “vulnerable” plaques associated with an increased risk of stroke, which is the Holy Grail of carotid imaging (5).

References:
1. Marja Berg, Zishu Zhang, Aki Ikonen, Petri Sipola, Reetta Kälviäinen, Hannu Manninen, and Ritva Vanninen. Multi-Detector Row CT Angiography in the Assessment of Carotid Artery Disease in Symptomatic Patients: Comparison with Rotational Angiography and Digital Subtraction Angiography. AJNR Am. J. Neuroradiol., May 2005; 26: 1022 – 1034.
2. Michael H. Lev, Javier M. Romero, Daniel N.F. Goodman, Ranjit Bagga, H. Young Kwon Kim, Neil A. Clerk, Robert H. Ackerman, and R. Gilberto Gonzalez. Total Occlusion versus Hairline Residual Lumen of the Internal Carotid Arteries: Accuracy of Single Section Helical CT Angiography. AJNR Am. J. Neuroradiol., Jun 2003; 24: 1123 – 1129.
3. T. Ohara, K. Toyoda, R. Otsubo, K. Nagatsuka, Y. Kubota, M. Yasaka, H. Naritomi, and K. Minematsu. Eccentric Stenosis of the Carotid Artery Associated with Ipsilateral Cerebrovascular Events. AJNR Am. J. Neuroradiol., Jun 2008; 29: 1200 – 1203.
4. Barreto M, Schoenhagen P, Nair A, Amatangelo S, Milite M, Obuchowski NA, Lieber ML, Halliburton SS. Potential of dual-energy computed tomography to characterize atherosclerotic plaque: ex vivo assessment of human coronary arteries in comparison to histology. J Cardiovasc Comput Tomogr. 2008 Jul-Aug;2(4):234-42. Epub 2008 Jun 12.
5. Chalela JA. Evaluating the carotid plaque: going beyond stenosis. Cerebrovasc Dis. 2009;27 Suppl 1:19-24. Epub 2009 Apr 3.

Does anyone have any thoughts on possible reasons for the discrepancies?

Neuroradiology 2009 Mar;51(3):193-8. Epub 2009 Jan 23.

This patient had left central retinal artery occlusion and acute ischemic optic neuropathy. There is restricted diffusion in the anterior left optic nerve which is much more obvious than the mild perineural enhancement on coronal postcontrast images.