Unenhanced versus multiphase MDCT in patients with hematuria, flank pain, and a negative ultrasound.

OBJECTIVES: To compare the impact of unenhanced and contrast-enhanced multi-detector computed tomography (MDCT) for the detection of urinary stones and urinary obstruction in patients with suspected renal colic. METHODS: 95 patients with suspected renal colic underwent a three-phase MDCT for evaluation of the urinary tract. The unenhanced scan and the multiphase examination were reviewed retrospectively by two radiologists for the characterization of urinary stones and signs of obstruction. Results of unenhanced MDCT were compared with those obtained during the second review of the entire multiphase examination. RESULTS: Overall diagnosis of urinary stones revealed an accuracy of 97.0% for unenhanced, and 98.9% for multiphase MDCT with a significant difference between both protocols (mixed-effects logistic regression: odds ratio 3.3; p=0.019). With 3 versus 15 false positive ratings, multiphase MDCT was superior to unenhanced MDCT for the diagnosis of urinary stones. There was no significant difference in detecting signs of obstruction. Inter-reader agreement for overall stone detection was excellent on both unenhanced (kappa 0.84) and multiphase (kappa 0.88) MDCT. CONCLUSION: Contrast-enhanced multiphase MDCT offers distinct advantages compared to an unenhanced approach for the assessment of urinary stone disease, and therefore should be considered as a complementary examination for patients with inconclusive findings.

[Acute gastrointestinal bleeding - diagnosis with computed tomography]. / Akute Gastrointestinale Blutung - Diagnose mit der Computertomographie.

Computed tomography represents a fast, non-invasive and accurate imaging modality for the diagnosis of acute gastrointestinal bleeding by providing information about localization and source of bleeding. Owing to its robustness and wide availability, it has the potential to be the first line imaging test in patients with acute life-threatening bleeding, for helping in the planning of interventional or surgical procedures.

Impact of vessel attenuation on quantitative coronary angiography with 64-slice CT.

The aim of the study was to determine the impact of vessel attenuation on quantitative 64-slice computed tomography coronary angiography (CTCA). CTCA and invasive quantitative coronary angiography (QCA) were performed in 100 consecutive patients (42 women, 58 men; mean age 64.4+/-9.4 years; age range 39-87 years). In QCA, stenoses were quantified with dedicated software, whereas in CTCA, stenosis severity was assessed with an electronic caliper tool: stenoses were graded in 10% steps and assigned as either a calcified or non-calcified lesion. Vessel attenuation in the left main (LMA) and the proximal right coronary artery (RCA) were measured and correlated with differences in quantifications of stenosis grade between QCA and CTCA. A total of 113 coronary stenoses were detected by both methods (94 significant and 19 non-significant); 52 stenoses were rated as non-calcified and 61 as calcified lesions. The mean difference between QCA and quantitative CTCA grading was 5.1+/-16.9% (range -27 to 46%) overall; 1.9+/-14.2% (range -27 to 38%) for non-calcified lesions and 7.8+/-18.6% (range -23 to 46%) for calcified lesions. Mean vessel attenuation was 362+/-76 HU (range 191-584 HU) in the LMA and 333+/-81 HU (range 162-564 HU) in the RCA. Attenuation did not significantly correlate with differences in QCA and CTCA gradings, neither overall nor for calcified or non-calcified lesions. When 64-slice CTCA is used, coronary vessel attenuation had no impact on the quantitative grading of stenoses.

Low-dose CT coronary angiography in the step-and-shoot mode: diagnostic performance.

OBJECTIVE: To investigate the performance of low-dose, dual-source computed tomography (DSCT) coronary angiography in the step-and-shoot (SAS) mode for the diagnosis of significant coronary artery stenoses in comparison with conventional coronary angiography (CCA). DESIGN, SETTING AND PATIENTS: Prospective, single-centre study conducted in a referral centre enrolling 120 patients (71 men, mean (SD) age 68 (9) years, mean (SD) body mass index 26.2 (3.2) kg/m2). All study participants underwent DSCT in the SAS mode and CCA within 14 days. Twenty-seven patients were given intravenous beta blockers for heart rate reduction before CT. Patients were excluded if a target heart rate 50%) stenoses. Sensitivity, specificity, negative (NPV) and positive predictive values (PPV) were determined, with CCA being the standard of reference. Radiation dose values were calculated. RESULTS: DSCT coronary angiography in the SAS mode was successfully performed in all 120 patients. Mean (SD) heart rate during scanning was 59 (6) bpm (range 44-69). 1773/1803 coronary segments (98%) were depicted with a diagnostic image quality in 109/120 patients (91%). The overall patient-based sensitivity, specificity, PPV and NPV for the diagnosis of significant stenoses were 100%, 93%, 94% and 100%, respectively. The mean (SD) effective dose of the CT protocol was 2.5 (0.8) mSv (range 1.2-4.4). CONCLUSIONS: DSCT coronary angiography in the SAS mode allows, in selected patients with a regular heart rate, the accurate diagnosis of significant coronary stenoses at a low radiation dose.

Combining dual-source computed tomography coronary angiography and calcium scoring: added value for the assessment of coronary artery disease.

OBJECTIVE: To prospectively investigate the diagnostic accuracy of dual-source 64-slice computed tomography coronary angiography (CTCA), calcium scoring (CS) and both methods combined for assessing significant coronary artery stenoses relative to conventional coronary angiography (CCA). DESIGN, SETTING AND PATIENTS: Prospective, single-centre study conducted in a referral centre enrolling 74 consecutive patients (24 women; mean age 62 (SD 12) years) from August-October 2006. All study participants underwent CS, CTCA and CCA. Diagnostic accuracy was calculated for CS, CTCA and both methods combined relative to CCA. Not-evaluative segments at computed tomography were considered false positive. RESULTS: CCA identified 139 stenoses in 36 patients. Average heart rate during CTCA was 68 (13) bpm (range 35-102 bpm), and 2% of segments (21/1001) in 11% of patients (8/74) were not evaluative. Considering these as false positives, per-patient sensitivity and specificity was 98% and 87%. When using CS cut-off values of 0 to exclude and >or=400 to predict stenosis, sensitivity and specificity of CS was 100% and 70%, respectively. Combining CS and CTCA in all patients correctly reclassified five patients, while six were falsely classified as stenotic, all of them correctly classified with CTCA alone. Using CS only in patients with not-evaluative segments correctly reclassified five patients while avoiding misclassifications (sensitivity 98%, specificity 100%). CONCLUSION: Dual-source CTCA allows the diagnosis of significant stenoses with a high diagnostic accuracy. Selectively combining CS with CTCA in patients with not-evaluative coronary segments improves specificity from 87% to 100% without decreasing the high sensitivity of 98%.