Background: Multidetector Computed Coronary Tomography (MDCT) has limited spatial and temporal resolutions. Systematic pre-medication with nitrates may improve coronary MDCT analysis.
Objective: The aim of this study was to evaluate the effect of systematic use of nitroglycerin prior to acquisition using the 256 MDCT on safety, hemodynamics and Image quality.
Method: We prospectively enrolled 72 consecutive patients with probable coronary artery disease who underwent image acquisition using 256 MDCT. Patients were randomized into 2 groups according to sealed envelopes determination; One group (36 patients) received 2 doses of 30 mg of sublingual nitroglycerin prior to acquisition (TNT group) while the other group (36 patients) did not receive the pre-acquisition nitrates (non-TNT group). Hemodynamic parameters were measured in both groups (before and after TNT in the TNT group). Global imaging quality assessment, number of analyzable segments, geometric measurements and contrast attenuation of each segment were performed and compared between the 2 groups.
Results: There was no demographic or clinical difference between the two groups. The use of beta-blockers was similar in both groups. There was a significant decrease of blood pressure without changes in the heart rate in the TNT group compared to the non-TNT group (p<0.002). Global imaging quality assessment was equal in both groups. A better signal-to-noise ratio (SNR) and contrast -to-noise ratio (CNR) were observed in the TNT group for distal and secondary segments. The number of non analyzable segments was higher in non-TNT group (15 segments, corresponding to 3 % vs. 4 segments, corresponding to 1%, p<0.05). Per segment mean diameter and area was greater in TNT group for the main coronary arteries and their secondary segments.
Conclusion: Sublingual nitroglycerin significantly improves coronary arteries geometry analysis, especially in secondary segments, without any adverse hemodynamic side effect, which might improve the coronary CT diagnostic accuracy.
By selecting patients referred for intravenous urography and by performing the urograms with either 50 ml of Hexabrix 320 (May & Baker Ltd) or 50 ml Urografin 370 (Schering AG) we have demonstrated that: ((a) 10 out of 10 patients (mean age 47 years) given Hexabrix showed opacification of the gallbladder and common bile-duct on CT images acquired at a mean time interval of 82 min from the injection, and (b) none of seven patients (mean age 52 years) given Urografin exhibited a similar effect on CT images acquired after a mean interval of 78 min.
The results of a study undertaken prospectively in 1983 and 1984 to assess the value of computed tomography (CT) and conventional tomography in the planning of radiotherapy for laryngeal cancer are presented. Of 32 cases treated in 1983, 23 had both CT scans and coronal plane tomography prior to radiotherapy. At the end of 1983 these radiographs were reviewed and an assessment made of their value in treatment planning. As a result of this review it was decided that cancers of the larynx confined to the vocal cords should routinely have conventional coronal plane tomograms rather than CT scans. All other cases were to have CT scans and not tomograms. The results of following this policy in 1984 confirm that it is effective. There was no detriment to patients with early vocal cord cancers in performing coronal plane tomograms rather than CT scans. The survival at 24 months of both cohorts was 93%. In the more invasive cancers of the larynx, greater information about the extent of the disease was obtained using CT scans, and improved treatment plans resulted. When compared with a historical group, there appears to be an advantage for local control, 27.3% of the study group suffering local recurrence as opposed to 53.6% of the historical group.
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