Chemometric methods for studying the relationships between trace elements in laryngeal cancer and healthy tissues.

A quick and reliable method for the evaluation and classification of two types of tissues is presented. Several chemometric methods were applied to evaluate multivariate data of the tissue samples with respect to the content of trace elements. The content of Pb, Al, Zn, Cd, Cu, Ni and Co was determined in samples of healthy and cancerous tissue obtained from 26 patients. Determination was done at milligram/kilogram level with inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic absorption spectroscopy (AAS) techniques. Contents of trace metals in studied tissues are not normally distributed; however, normal distribution was confirmed for log values. There is a statistically significant difference in the content of Zn, Cd, Cu and Al (p<0.01) and Ni and Co (p<0.05) when healthy tissue is compared to cancerous one. Correlation between contents of trace elements for studied tissues was positive; the highest was found between Zn and Cu. A chemometric methodology seems to be a promising tool for classifications of the tissue samples.

Squamous cell cancer of hypopharynx and larynx - evaluation of metastatic nodal disease based on computed tomography perfusion studies.

BACKGROUND AND PURPOSE: In patients with squamous cell cancer metastatic disease in lymph nodes still remains the single most important negative predicting factor and when detected, it reduces overall 5-year survival by 50%. The aim of the study was to evaluate contrast-enhanced computed tomography (CECT) with computed tomography perfusion (CTP) examination in order to differentiate malignant from non-malignant cervical lymph nodes in patients with squamous cell cancer of hypopharynx and larynx. MATERIAL/METHODS: This was a prospective three-center study. From November 2007 until March 2010 33 consecutive patients with squamous cell cancer of the hypopharynx and 27 patients with laryngeal cancer underwent computed tomography (CT) examination followed by CTP. During first part of examination 80 ml of contrast was administered, with flow rate 1 ml/s and 100 s delay; standard head and neck examination was performed. Next, perfusion images were acquired with the coverage of 8 cm and different groups of lymph nodes were evaluated - groups II, III, IV and V. Perfusion maps for basic parameters (blood flow [BF], blood volume [BV], mean transit time [MTT] and permeability surface [PS]) were reconstructed for all patients using dedicated software. The long and short axis diameters, the density of the node before and after contrast medium administration and average values of each perfusion parameter were calculated for every node separately. Results were compared with histologic analysis of resected nodes. RESULTS: Out of the total number of 293 nodes evaluated on CECT and CTP it was possible to correlate 208 resected nodes with histologic findings. 125 of them were proven to be malignant and 83 were benign. Malignant nodes showed remarkably higher density and hyperperfusion, comparing to benign ones. The average density values in Hounsfield units (HU) for cervical nodes were: 91.9HU for metastatic comparing to 72.3 HU for non-metastatic, but this difference did not show statistical significance. The average value of BF in malignant nodes was 136.4 ml/100g/min, BV was 7.7 ml/100g, MTT was 4.4s and PS was 19.4 ml/100g/min. The average values for benign nodes were: BF was 80.7 ml/100g/min, BV was 4.7 ml/100g, MTT was 5.6s and PS was 12.8 ml/100g/min. Comparing to non-malignant nodes, malignant ones showed significantly higher BF, BV and PS values (p<0.05). CONCLUSIONS: Although CECT findings may draw our attention, pointing at abnormal morphology of the node, CTP seems to provide additional functional information regarding its possible malignancy. CTP may be useful in differentiation between malignant and benign lymph nodes, based on evaluation of the value of BF, BV and PS.

How to reliably evaluate middle ear diseases? Comparison of different methods of post-processing based on multislice computed tomography examination.

CONCLUSIONS: Multislice computed tomography (MSCT) virtual endoscopy was useful in evaluating mainly post-traumatic and postoperative cases. In other pathological conditions axial images and MPR reformations were most useful. OBJECTIVES: Evaluation of cross-sectional images, multiplanar 2-D reformations, 3-D reconstructions and virtual endoscopy (VE) in assessment of the middle ear in inflammatory diseases, trauma, otosclerosis and tumours. Comparison of each method and correlation with surgical findings. MATERIALS AND METHODS: Investigations were carried out in 80 patients with middle ear pathology. In each case MSCT of the petrous bone was performed. In addition to cross-sectional native scans, frontal and sagittal images were achieved using MPR reconstructions. 3-D volume rendering (VR) and VE images were also generated. The value of native scans information, 2-D, 3-D reconstructions and VE of the tympanic cavity structures was assessed in comparison to intraoperative findings. RESULTS: MPR reconstructions were most useful in the assessment of skull base trauma, skull base tumours and in cases of chronic middle ear inflammation. Highly vascularized tumours, disruption of ossicular chain and stapes prosthesis were best evaluated on 3-D reconstructions. Axial images proved to be the best for otosclerosis interpretation.

Differentiation between cholesteatoma and inflammatory process of the middle ear, based on contrast-enhanced computed tomography imaging.

OBJECTIVE: To assess the usefulness of delayed post-contrast computed tomography (CT) examination for the detection of residual or recurrent cholesteatoma after canal wall up tympanoplasty. STUDY DESIGN AND SETTING: This prospective, non-randomized study, set within an academic medical centre, included 17 consecutive patients who had undergone canal wall up tympanoplasty for cholesteatoma, with possible recurrence. Pre-contrast CT scans and delayed post-contrast images were compared with second look surgical findings. RESULTS: A residual or recurrent cholesteatoma was found in eight of the 17 patients at revision surgery and was correctly diagnosed on post-contrast CT images in six patients (75 per cent). In the two misdiagnosed cases, cholesteatoma pearls smaller than 2.5 mm were not seen on post-contrast CT. The sensitivity of the imaging test was 75 per cent, the specificity was 60.1 per cent, the positive predictive value was 88.1 per cent and the negative predictive value was 81.8 per cent. CONCLUSION: Computed tomography with delayed post-contrast images is a sensitive imaging modality for the detection of residual cholesteatoma. If proven reliable, this method of non-invasive imaging could spare the patient unnecessary revision surgery.

Changes in cerebral hemodynamics after carotid stenting: evaluation with CT perfusion studies.

PURPOSE: To determine changes in cerebral perfusion parameters, based on CT perfusion imaging, in patients after unilateral transluminal angioplasty and stent placement. MATERIAL AND METHODS: 74 patients with symptomatic high - grade internal carotid artery stenosis (>70%) were studied with CT perfusion imaging before and - on average - 70 hours and 172 days after carotid stent placement. There were 50 patients with unilateral carotid artery stenosis and 24 with stenosis and accompanying contralateral internal carotid artery occlusion. CT examination was performed using a multidetector helical CT scanner (Light Speed Ultra Advantage, GE Healthcare, USA). Maps showing the absolute values of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were generated. RESULTS: In a group with unilateral carotid artery stenosis perfusion deficits were present in 84% of patients, ipsilaterally to stenosis. MTT elongation was noted (6.2-6.8s) together with decreased values of CBF (40-46ml/100g/min) and slightly increased CBV (3.2ml/100g). In this group, 3 days after stenting, 30% of patients had perfusion deficits, and after 6 months only 6%. In a group with carotid artery stenosis and contralateral artery occlusion severe perfusion deficits were noted in both hemispheres and they were present in 100% of patients. 6 months after stenting hypoperfusion was observed only in 17% of patients. CONCLUSIONS: Brain perfusion deficits, observed in a majority of patients with carotid artery stenosis tend to improve considerably after carotid artery stenting, in long - term follow up.