Crohn's disease recurrence in patients with ileocolic anastomosis: Value of computed tomography enterography with water enema

Objectives

the main objective of the present work was to determine the diagnostic value of CT-enterography with water enema (CTe-WE) in the assessment of the ileocolic anastomosis in patients with Crohn's disease (CD). The prevalence of synchronous inflammatory lesions (SILs) involving gastrointestinal segments distinct from the anastomosis was also determined. Further, the association between the type of ileocolic anastomosis and the behavior (i.e. inflammatory, stricturing, penetrating) of CD recurrence was evaluated.

Methods

51 patients were retrospectively included (26 [51%] male and 25 [49%] female; mean age: 52.88 years ± 13.35). Ileocolic anastomoses were: 18 (35.3%) stapled side-to-side, 17 (33.3%) end-to-side, and 16 (31.4%) end-to-end. CTe-WEs were reviewed in consensus by two gastrointestinal radiologists. Endoscopy and medical records were used as reference standards.

Results

CTe-WE yielded 95.35% sensitivity (CI 95%: 84.19–99.43%), 75.00% specificity (CI 95%: 34.91–96.81%), and 92.15% diagnostic accuracy (CI 95%: 81.31–98.02%). Anastomotic recurrence was found in 41/51 (80.4%) patients, including 30/41 (73.2%) cases of isolated anastomotic recurrence, and 11/41 (26.8%) cases of anastomotic recurrence with a SIL. A significant lower prevalence of stricturing recurrence was observed in patients with stapled side-to-side anastomoses (p = 0.033).

Conclusions

CTe-WE provides a good distension of both sides of ileocolic anastomoses allowing the detection of SILs.     

Routine use of modified CT Enterography in patients with acute abdominal pain

Purpose

To evaluate routine use of CT Enterography (CTE) in patients presenting with non-traumatic acute abdominal pain with respect to patient tolerance, imaging of intestinal detail along with conventional abdominal evaluation.

Materials and methods

Modified CTE was performed in 165 consecutive patients with acute abdominal pain: ingestion, as tolerated, of 900–1200 ml of 2% barium suspension + 5 ml of Gastrografin over 45 min; 150 ml of iv contrast given in two boluses (50 and 100 ml) 3 min apart (split bolus injection protocol). Axial, coronal and sagittal reformats were reviewed by two radiologists and graded on a 5-point scale (5 best) in regard to GI tract luminal opacification and distension and abdominal organ and vascular enhancement.

Results

In 81 patients the cause of abdominal pain was identified (intestinal in 54 and extraintestinal in 27). Oral contrast reached cecum in 76% of the patients and the small bowel was well distended and opacified (medians = 4). Mucosa detail was good (median = 3) and there was significant (p < 0.0001) correlation between bowel opacification and distension for both jejunum and ileum. A combined nephrographic and excretory phase was achieved (medians 4 and 5, respectively), while the great vessels were well opacified, allowing for vascular evaluation (median = 5). The rest of the abdominal structures were well visualized.

Conclusion

Modified CTE is well tolerated by patients with acute non-traumatic abdominal pain, and can be used routinely as a non-invasive examination informative of bowel, vessel and organ pathology in Emergency Department patients.     

Role of CT enterography in assessment of Crohn’s disease activity: Correlation with histopathologic diagnosis

Aim

To evaluate the radiological signs of gastro-intestinal inflammation at CT enterography and to assess its accuracy in determining the degree of activity in patients with Crohn’s disease (CD).

Methods

CT enterography was performed in 26 CD patients and evaluated for the following parameters: mucosal enhancement, abnormal wall thickening, engorged vasa recta, increased density of the mesenteric fat and enlarged mesenteric lymph nodes. Correlations between CT findings and histopathologic results were made using McNemar test.

Results

There was no significant statistical difference in mucosal enhancement and wall thickening between moderate and severe disease (P = 0.631 and 0.138, respectively) whereas engorged vasa recta, fat edema and lymph node enlargement had successfully discriminated between moderate and severe histological findings (P = 0.009, <0.001 and 0.045, respectively). Moderate disease was diagnosed correctly by CTE in 50% of cases while severe disease was diagnosed in 100% of cases. When we reconditioned the presence of two CTE severity criteria to diagnose severe disease, the sensitivity to predict moderate disease activity increased to 80%.

Conclusion

CT enterography is a sensitive and specific non-invasive imaging modality for evaluating the degree of activity of Crohn’s disease, and should be considered in its diagnostic and management algorithms.     

Role of CT enterography in obscure gastrointestinal bleeding

Background

Obscure gastrointestinal bleeding is a radiological challenge where in almost half of the patients; the origin of the blood loss remains unexplained.

Aim

To highlight the use of dual phase CT enterography for the detection of obscured gastrointestinal bleed.

Patient and methods

Twenty consecutive patients (11 men and 9 women) with OGIB were included in this study; their age ranged from 28 to 67 years (mean age 45.6 years). CT enterography was performed first with a non-contrast scan, followed by biphasic contrast-enhanced CT at 35 and 70 s at a rate of 4 mL/s.

Results

On CT enterography, 12 patients (60%) were negative while 8 patients (40%) had positive findings as follows: one patient (5%) had celiac disease, 1 patient (5%) had active Crohn’s disease and another patient (5%) had ischemic bowel changes. Five patients (20%) had small bowel neoplasms as follows: (1 patient had ileal angiolipoma, 1 patient had ileal hypervascular GIST, 1 patient had duodenal GIST, 1 patient had duodenal carcinoid and 1 patient had jejunal villous adenoma).

Conclusion

MDCT enterography has a good diagnostic accuracy in the evaluation of patients with OGIB and can reliably indicate the source of GI bleeding and guide subsequent therapy.     

Quantification of coronary artery stenosis with high-resolution CT in comparison with histopathology in an ex vivo study

Purpose

To investigate the ex vivo performance of high-resolution computed tomography (CT) for quantitative assessment of percentage diameter stenosis in coronary arteries compared to histopathology.

Materials and methods

High-resolution CT was performed in 26 human heart specimens after the injection of iodinated contrast media into the coronary arteries. Coronary artery plaques were visually identified on CT images and the grade of stenosis for each plaque was measured with electronic calipers. All coronary plaques were characterized by histopathology according to the Stary classification, and the percentage of stenosis was measured.

Results

CT depicted 84% (274/326) of all coronary plaques identified by histology. Missed plaques by CT were of Stary type I (n = 31), type II (n = 16), and type III (n = 5). The stenosis degree significantly correlated between CT and histology (r = 0.81, p < 0.001). CT systematically overestimated the stenosis of calcified plaques (mean difference - 11.0 ± 9.5%, p < 0.01) and systematically underestimated the stenosis of non-calcified plaques (mean difference −6.8 ± 10.4%, p < 0.05), while there was no significant difference for mixed-type plaques (mean difference −0.4 ± 11.7%, p = 0.85). There was a significant underestimation of stenosis degree as measured by CT for Stary II plaques (mean difference −14 ± 9%, p < 0.01) and a significant overestimation for Stary VII plaques (mean difference 9 ± 10%, p < 0.05), but there was no significant difference in stenosis degree between both modalities for other plaque types.

Conclusions

High-resolution CT reliably depicts advanced stage coronary plaques with an overall good correlation of stenosis degree compared to histology, however, the degree of stenosis is systematically overestimated in calcified and underestimated in non-calcified plaques.     

The impact of iterative reconstruction on image quality and radiation dose in thoracic and abdominal CT

Purpose

To compare the image quality and radiation dose between iterative reconstruction (IR) and standard filtered back projection (FBP) in CT of the chest and abdomen.

Materials and methods

Thoracic CT was performed in 50 patients (38 male, 12 female; mean age, 51 ± 23 yrs; range, 7–85 yrs) and abdominal CT was performed in 50 patients (36 male, 14 female; mean age, 62 ± 13 yrs; range, 20–85 yrs), using IR as well as FBP for image reconstruction. Image noise was quantitatively assessed measuring standard deviation of Hounsfield Units (HU) in defined regions of interest in subcutaneous tissue. Scan length and Computed Tomography Dose Index (CTDI) were documented. Scan length, image noise, and CTDI of both reconstruction techniques were compared by using paired tests according to the nature of variables (McNemar test or Student t test). Overall subjective image quality and subjective image noise were compared.

Results

There was no significant difference between the protocols in terms of mean scan length (p > 0.05). Image noise was statistically significantly higher with IR, although the difference was clinically insignificant (13.3 ± 3.0 HU and 13.6 ± 3.0 HU for thoracic CT and 11.5 ± 3.1 HU and 11.7 ± 3.0 HU for abdominal CT, p < 0.05). There was no significant difference in overall subjective image quality and subjective image noise. The radiation dose was significantly lower with IR. Volume-weighted CTDI decreased by 64% (6.2 ± 2.5 mGy versus 17.1 ± 9.5 mGy, p < 0.001) for thoracic CT and by 58% (7.8 ± 4.6 mGy versus 18.5 ± 8.6 mGy, p < 0.001) for abdominal CT.

Conclusions

Our study shows that in thoracic and abdominal CT with IR, there is no clinically significant impact on image quality, yet a significant radiation dose reduction compared to FBP.     

Novel phase-based noise reduction strategy for quantification of left ventricular function and mass assessment by cardiac CT: Comparison with cardiac magnetic resonance

Background

Tube current modulation in retrospective ECG gated cardiac computed tomography (CT) results in increased image noise and may reduce the accuracy of left ventricular (LV) ejection fraction (EF) and mass assessment.

Objective

To examine the effects of a novel CT phase-based noise reduction (NR) algorithm on LV EF and mass quantification as compared to cardiac magnetic resonance (CMR).

Methods

In 40 subjects, we compared the LV EF and mass between CT and CMR. In a subset of 24 subjects with tube current modulated CT, the effect of phase-based noise reduction strategies on contrast-to-noise ratio (CNR) and the assessment of LV EF and mass was compared to CMR.

Results

There was excellent correlation between CT and CMR for EF (r = 0.94) and mass (r = 0.97). As compared to CMR, the limits of agreement improved with increasing strength of NR strategy. There was a systematic underestimation of LV mass by CT compared to CMR with no NR (−10.3 ± 10.1 g) and low NR (−10.3 ± 12.5 g), but was attenuated with high NR (−0.5 ± 8.3 g). Studies without NR had lower CNR compared to low and high NR at both the ES phase and ED phase (all p < 0.01).

Conclusions

A high NR strategy on tube current modulated functional cardiac CT improves correlation of EF compared to CMR and reduces variability of EF and mass evaluation by increasing the CNR. In an effort to reduce radiation dose with tube current modulation, this strategy provides better image quality when LV function and mass quantification is needed.     

Single-energy low-voltage arterial phase MDCT scanning increases conspicuity of adenocarcinoma of the pancreas

Purpose

To test a single-energy low-voltage CT protocol for pancreatic adenocarcinoma.

Methods and materials

A total of 30 patients with pathology-proven pancreatic adenocarcinoma underwent 64-row MDCT with arterial phase at 80 kV and were compared to a similar group of 30 patients scanned with a 120 kV protocol. Scans were compared for quantitative image parameters (attenuation and standard deviation in the pancreas, tumor, aorta), CTDI and DLP using an unpaired t-test. Image noise values for each protocol (SD of the psoas) were compared using an unpaired t-test. Effective dose was calculated for each protocol. CNR (=conspicuity/SDnoise) and FOM (CNR²/ED) were calculated. The Catphan600 phantom was used to evaluate image non-uniformity, noise, spatial resolution, and low contrast detectability.

Results

Mean patient weight was 68 kg in the study group and 73 kg in the control group (p = 0.0355), while patient diameters at the celiac axis were not significantly different. Mean attenuation was significantly higher at 80 kV in the aorta (517.5 ± 116.4 vs 290.3 ± 76.4 HU) and normal pancreas (154.0 ± 39.95 vs 90.02 ± 19.01 HU) (all p < 0.0001), while no significant difference was observed for adenocarcinoma (61.43 ± 35.61 vs 47.45 ± 18.95; p = n.s.). CTDI and DLP were significantly lower at 80 kV (6.00 ± 0.90 mGy vs 10.24 ± 2.93 mGy, and 180.4 ± 35.49 mGy cm vs 383.8 ± 117 mGy cm, respectively; all p < 0.0001). Tumor conspicuity (HU_pancreas − HU_tumor) was significantly higher at 80 kV (94.2 ± 39.3 vs 39.5 ± 22 HU; p < 0.0001). Mean image noise was significantly higher at 80 kV (28.32 ± 10.06 vs 19.7 ± 7.1 HU; p < 0.0001). Effective dose was significantly lower at 80 kV (1.984 ± 0.39 vs 5.75 ± 1.75 mSv; p < 0.0001). The total DLP for the exam was 1024 ± 31.86 mGy cm for the 80 kV protocol and 1357 ± 62.60 mGy cm for the 120 kV protocol (p < 0.0001).Phantoms showed higher non-uniformity, slightly higher noise, slightly lower MTF (50%) and slightly higher percentage contrast for the 80 kV protocol.

Conclusion

Single-source 80 kV pancreatic phase scanning results in higher conspicuity of pancreatic adenocarcinoma and FOM and in significant dose reduction while maintaining acceptable image quality.     

The roles of the liver and pancreas in renal nutcracker syndrome

Introduction

To assess the frequency and significance of presence of the liver and pancreas at the left renal vein (LRV) level in patients with suspected renal nutcracker syndrome (NCS).

Materials and methods

We included 101 patients with hematuria who underwent urography three-dimensional CT between April 2009 and November 2013. These patients were divided into NCS (n = 25) and non-NCS (n = 76) patients according to the following CT criteria: (1) the presence of beak sign and (2) hilar-aortomesenteric left renal vein diameter ratio >4. Patients were grouped according to the presence of the liver and pancreas at the LRV: group LP (both liver and pancreas), group L (only liver), group P (only pancreas), and group O (neither liver nor pancreas). The difference in the frequencies of groups was analyzed between NCS and non-NCS patients. Multivariate analysis was used to determine the independent factors between NCS and non-NCS patients.

Results

The frequencies of group LP, group L, group P, and group O in NCS vs. non-NCS were 88% vs. 5.3% (p < 0.001), 4.0% vs. 2.6% (p = 0.75), 4.0% vs. 11.8% (p = 0.45), 4.0% vs. 80.3% (p < 0.001), respectively. Multivariate analysis demonstrated that group was a predictor for differential diagnosis between NCS and non-NCS (p = 0.022), and group LP was an independent factor for the presence of NCS (odds ratio, 43.8; 95% confidence interval, 3.8–500.3; p < 0.002; reference, group O).

Conclusion

The presence of the liver and pancreas at the level of the LRV was frequently found in NCS and was the independent factor for NCS.     

Significance of peribiliary oedema on computed tomography in diagnosis and severity assessment of acute cholangitis

Objectives

To evaluate usefulness of peribiliary oedema on computed tomography (CT) in diagnosing acute cholangitis and assessing its severity.

Materials and methods

Sixty patients (male 59%, mean age 67.3 years) who underwent endoscopic retrograde biliary drainage (ERBD) for suspected biliary obstruction within 6 h after contrast-enhanced CT were evaluated. Two radiologists performed a consensus evaluation of CT for the presence of peribiliary oedema. Patients were divided into the cholangitis group and the non-cholangitis group based on clinical and ERBD findings, and CT results were compared between the two groups. In the cholangitis group, laboratory values and blood culture results were compared between those with and without peribiliary oedema. Chi-squared test was used for analyses.

Results

Of 60 enrolled patients, there were 46 patients in the cholangitis group and 14 patients in the non-cholangitis group. Peribiliary oedema was seen in 24/46 (52.2%) patients in the cholangitis group and 3/14 (23.3%) patients in the non-cholangitis group (p = 0.043). In the cholangitis group, positive blood culture was seen in 12/24 (50%) patients with peribiliary oedema and 4/22 (18.1%) patients without it (p = 0.03).

Conclusions

Peribiliary oedema appears to be useful for diagnosis and severity assessment of acute cholangitis.     

Optimal sequence timing of CT angiography and perfusion CT in patients with stroke

Objective

Standard stroke CT protocols start with non-enhanced CT followed by perfusion-CT (PCT) and end with CTA. We aimed to evaluate the influence of the sequence of PCT and CTA on quantitative perfusion parameters, venous contrast enhancement and examination time to save critical time in the therapeutic window in stroke patients.

Methods and materials

Stroke CT data sets of 85 patients, 47 patients with CTA before PCT (group A) and 38 with CTA after PCT (group B) were retrospectively analyzed by two experienced neuroradiologists. Parameter maps of cerebral blood flow, cerebral blood volume, time to peak and mean transit time and contrast enhancements (arterial and venous) were compared.

Results

Both readers rated contrast of brain-supplying arteries to be equal in both groups (p = 0.55 (intracranial) and p = 0.73 (extracranial)) although the extent of venous superimposition of the ICA was rated higher in group B (p = 0.04). Quantitative perfusion parameters did not significantly differ between the groups (all p > 0.18), while the extent of venous superimposition of the ICA was rated higher in group B (p = 0.04). The time to complete the diagnostic CT examination was significantly shorter for group A (p < 0.01).

Conclusion

Performing CTA directly after NECT has no significant effect on PCT parameters and avoids venous preloading in CTA, while examination times were significantly shorter.     

Semi-automated scoring of pulmonary emphysema from X-ray CT: Trainee reproducibility and accuracy

Objective

We developed a semi-automated tool to quantify emphysema from thoracic X-ray multi-detector (64-slice) computed tomography (CT) for training purposes and multi-reader studies.

Materials and Methods

Thoracic X-ray CT was acquired in 93 ex-smokers, who were evaluated by six trainees with little or no expertise (trainees) and a single experienced thoracic radiologist (expert). A graphic user interface (GUI) was developed for emphysema quantification based on the percentile of lung where a score of 0 = no abnormalities, 1 = 1–25%, 2 = 26–50%, 3 = 51–75% and 4 = 76–100% for each lung side/slice. Trainees blinded to subject characteristics scored randomized images twice; accuracy was determined by comparison to expert scores, density histogram 15th percentile (HU₁₅), relative area at −950 HU (RA₉₅₀), low attenuation clusters at −950 HU (LAC₉₅₀), −856 HU (LAC₈₅₆) and the diffusing capacity for carbon monoxide (DL_CO%pred). Intra- and inter-observer reproducibility was evaluated using coefficients-of-variation (COV), intra-class (ICC) and Pearson correlations.

Results

Trainee–expert correlations were significant (r = 0.85–0.97, p < 0.0001) and a significant trainee bias (0.15 ± 0.22) was observed. Emphysema score was correlated with RA₉₅₀ (r = 0.88, p < 0.0001), HU₁₅ (r = −0.77, p < 0.0001), LAC₉₅₀ (r = 0.76, p < 0.0001), LAC₈₅₆ (r = 0.74, p = 0.0001) and DL_CO%pred (r = −0.71, p < 0.0001). Intra-observer reproducibility (COV = 4–27%; ICC = 0.75–0.94) was moderate to high for trainees; intra- and inter-observer COV were negatively and non-linearly correlated with emphysema score.

Conclusion

We developed a GUI for rapid and interactive emphysema scoring that allows for comparison of multiple readers with clinical and radiological standards.     

The relationship between the prevalance and size of lumbar ossified ligamentum flavum and the presence and degree of facet joint degeneration

Objectives

To investigate whether there is any relationship between the prevalence and the dimension of OLF and the presence and degree of facet joint degeneration. In addition, it revealed the prevalence and distribution of lumbar OLF with regard to age and spinal levels.

Methods

The stone protocol abdominal CT images of 114 patients were retrospectively analyzed. Presence of OLF, degenerative changes in the posterior vertebral elements was evaluated on axial CT images and incidence for each finding was determined. Additionally, the degree of facet joint degeneration and size of OLF was evaluated and recorded. All findings were also grouped based on age and lumbar level.

Results

OLF has been observed in 40 (35%) individuals at 76 (13%) lumbar levels. OLF has been most frequently encountered at the upper lumbar levels. Its frequency and size showed correlation to increased age. Frequency of OLF correlated with the presence of degenerative changes of in the posterior elements (p < 0.001). There was an association between the OLF size and the presence (p = 0.001) and degree of the degeneration in the posterior elements. There was no lumbar level case where the degree of OLF would lead to enough narrowing to be symptomatic.

Conclusions

OLF prevalence and sizes increase parallel to age. Posterior elements’ degenerative changes facilitate OLF development. A close relation exists between OLF size and facet joint degeneration. A direct relationship exists between OLF size and the degree of posterior elements degeneration. It is highly probable for lumbar level OLF size to be insufficient to cause any symptoms.     

Detection of Crohn's disease: Comparison of CT and MR enterography without anti-peristaltic agents performed on the same day

Objective

To directly compare CT enterography (CTE) and MR enterography (MRE) without antiperistaltic agents.

Materials/methods

26 patients referred for CTE underwent CTE immediately followed by MRE without use of an anti-peristaltic agent. Each study was evaluated on a 10 point scale for exam quality, level of diagnostic confidence, and presence of Crohn's disease. Kappa analysis was performed to determine the degree of agreement between the CTE and MRE of each patient.

Results

25 patients completed the MRE. The quality of the CTEs was judged as excellent by both readers (reader 1 = average 9.5/10, reader 2 = average 9.1/10). The quality of the MREs was ranked lower than the CTEs by both readers (reader 1 = average 8.9/10, reader 2 = average 7.2/10), which was statistically significant (p < 0.05). The level of confidence in interpretation was not significantly different between CTE and MRE for reader 1 or 2 (p = 0.3). There was substantial agreement between readers for the presence or absence of Crohn's disease on both CTE (kappa = 0.75) and MRE (kappa = 0.67).

Conclusion

MR enterography without anti-peristaltic agents results in high diagnostic confidence and excellent agreement for the presence of Crohn's disease.     

3D automatic exposure control for 64-detector row CT: Radiation dose reduction in chest phantom study

Purpose

The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study.

Materials and methods

A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis.

Results

When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05).

Conclusion

This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality.     

Assessment of image quality of 64-row Dual Source versus Single Source CT coronary angiography on heart rate: A phantom study

Purpose

To assess the influence of temporal resolution on image quality of computed tomographic (CT) coronary angiography by comparing 64-row Dual Source CT (DSCT) and Single Source CT (SSCT) at different heart rates.

Methods

An anthropomorphic moving heart phantom was scanned at rest, and at 50 beats per minute (bpm) up to 110 bpm, with intervals of 10 bpm. 3D volume rendered images and curved multi-planar reconstructions (MPRs) were acquired and image quality of the coronary arteries was rated on a 5-points scale (1 = poor image quality with many artefacts, 5 = excellent image quality) for each heart rate and each scanner by 3 observers. Paired sample t-test and Wilcoxon Signed Ranks test were used to assess clinically relevant differences between both modalities.

Results

The mean image quality scores at 70, 100 and 110 bpm were significantly higher for DSCT compared to SSCT. The overall mean image quality scores for DSCT (4.2 ± 0.6) and SSCT (3.0 ± 1.1) also differed significantly (p < 0.001).

Conclusion

These initial results show a clinically relevant overall higher image quality for DSCT compared to SSCT, especially at heart rates of 70, 100 and 110 bpm. With its comparatively high image quality and low radiation dose, DSCT appears to be the method of choice in CT coronary angiography at heart rates above 70 bpm.     

Technical quality of CT colonography in relation with diverticular disease

Objective

The aim of the study is to explore how the technical quality of the examination was affected by diverticular disease.

Materials and methods

We retrospectively evaluated a consecutive series of 78 subjects who underwent CTC for screening (n = 58) or staging (n = 20) colorectal cancer, 38 of them (49%) after an incomplete optical colonoscopy. Patients were administered a mild laxative and a iodinated contrast material for fecal tagging. We scored both the bowel preparation and the overall colon distension as poor, good, or optimal and measured the mean sigmoid colon diameter. We counted the number of diverticula and classified patients as having or not a severe diverticular disease (SDD). The number of the prompts of computer aided diagnosis (CAD) per patient was also considered. Mann–Whitney U and χ² tests were performed.

Results

No CTC complications occurred. The bowel cleansing was poor in 8 (10%) patients, good in 29 (37%) and optimal in 41 (53%); colon distension was poor in 7 (9%) patients, good in 38 (49%), and optimal in 33 (42%). Fifty-four (69%) showed diverticula and 30 (38%) had an SDD. Bowel cleansing and distension were not significantly impaired by neither diverticula (p > 0.590) nor the SDD (p > 0.110). Mean sigmoid colon diameter was reduced in presence of diverticula (28 mm versus 23 mm, p = 0.009) or SDD (26 mm versus 22 mm, p = 0.016). The mean number of CAD prompts per patient was not significantly increased by the presence of SDD (p = 0.829).

Conclusions

Bowel cleansing and distension at CTC were not influenced by the presence of diverticular disease.     

Image-guided radiofrequency ablation of hepatocellular carcinoma (HCC): Is MR guidance more effective than CT guidance?

Objectives

The purpose of the study was to retrospectively compare technique effectiveness of computed tomography (CT)-guided versus magnetic resonance (MR)-guided radiofrequency (RF) ablation of hepatocellular carcinoma (HCC).

Materials and methods

In 35 consecutive patients 53 CT-guided (n = 29) or MR-guided (n = 24) ablation procedures were performed in the treatment of 56 (CT: 29; MR: 27) HCC. The entire ablation procedure was performed at a multislice CT-scanner or an interventional 0.2-Tesla MR-scanner. Assessment of treatment response was based on dynamic MR imaging at 1.5 Tesla. The mean follow-up was 22.9 months. Primary technique effectiveness was assessed 4 months after ablation therapy. Secondary technique effectiveness was assessed 4 months after a facultative second ablation procedure. Primary and secondary technique effectiveness of CT-guided and MR-guided RF ablation was compared by using Chi-Square (likelihood ratio) test.

Results

Primary technique effectiveness after a single session was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and 23/29 (79.3%) HCC after CT-guided RF ablation (Chi-Square: p = 0.04). Secondary technique effectiveness was achieved in 26/27 (96.3%) HCC after MR-guided RF ablation and in 26/29 (89.7%) HCC after CT-guided RF ablation (Chi-Square: p = 0.32). A local tumor progression was detected in 8/52 (15.4%) tumors after initial technique effectiveness. Major complications were detected after 3/53 (5.7%) ablation procedures.

Conclusions

CT-guided and MR-guided RF ablations are locally effective therapies in the treatment of HCC. Due to a higher rate of primary technique effectiveness MR-guided RF ablation may reduce the number of required sessions for complete tumor treatment.     

Enhanced temporal resolution at cardiac CT with a novel CT image reconstruction algorithm: Initial patient experience

Objective

To evaluate the effect of a temporal resolution improvement method (TRIM) for cardiac CT on diagnostic image quality for coronary artery assessment.

Materials and methods

The TRIM-algorithm employs an iterative approach to reconstruct images from less than 180° of projections and uses a histogram constraint to prevent the occurrence of limited-angle artifacts. This algorithm was applied in 11 obese patients (7 men, 67.2 ± 9.8 years) who had undergone second generation dual-source cardiac CT with 120 kV, 175–426 mAs, and 500 ms gantry rotation. All data were reconstructed with a temporal resolution of 250 ms using traditional filtered-back projection (FBP) and of 200 ms using the TRIM-algorithm. Contrast attenuation and contrast-to-noise-ratio (CNR) were measured in the ascending aorta. The presence and severity of coronary motion artifacts was rated on a 4-point Likert scale.

Results

All scans were considered of diagnostic quality. Mean BMI was 36 ± 3.6 kg/m². Average heart rate was 60 ± 9 bpm. Mean effective dose was 13.5 ± 4.6 mSv. When comparing FBP- and TRIM reconstructed series, the attenuation within the ascending aorta (392 ± 70.7 vs. 396.8 ± 70.1 HU, p > 0.05) and CNR (13.2 ± 3.2 vs. 11.7 ± 3.1, p > 0.05) were not significantly different. A total of 110 coronary segments were evaluated. All studies were deemed diagnostic; however, there was a significant (p < 0.05) difference in the severity score distribution of coronary motion artifacts between FBP (median = 2.5) and TRIM (median = 2.0) reconstructions.

Conclusion

The algorithm evaluated here delivers diagnostic imaging quality of the coronary arteries despite 500 ms gantry rotation. Possible applications include improvement of cardiac imaging on slower gantry rotation systems or mitigation of the trade-off between temporal resolution and CNR in obese patients.     

Quantitative hepatic CT perfusion measurement: Comparison of Couinaud's hepatic segments with dual-source 128-slice CT

Purpose

To compare the quantitative liver computed tomography perfusion (CTP) differences among eight hepatic segments.

Materials and methods

This retrospective study was based on 72 acquired upper abdomen CTP scans for detecting suspected pancreas tumor. Patients with primary or metastatic liver tumor, any focal liver lesions except simple cyst (<3 cm in diameter), history of liver operation or splenectomy, evidence of liver cirrhosis or invasion of portal vein were excluded. The final analysis included 50 patients (M:F = 21:29, mean age = 43.2 years, 15–76 years). Arterial liver perfusion (ALP), portal-venous perfusion (PVP), total hepatic perfusion (THP = ALP + PVP), and hepatic perfusion index (HPI) of each hepatic segment were calculated and compared by means of one-way analysis of variance (ANOVA) and the Bonferonni correction method.

Results

Compared to hepatic segments 5, 6, 7 and 8, segments 2 and 3 showed a tendency of higher ALPs, lower PVPs, and higher HPIs, most of which were statistically significant (p < 0.05). Hepatic segments 1 and 4 had higher mean values of ALP and HPI and lower mean values of PVP than segments 5, 6, 7 and 8 as well, although no significant differences were detected except for ALP and HPI for liver segments 1 and 7 (p = 0.001 and 0.035 respectively), and ALP for liver segments 1 and 5 (p = 0.039). Higher ALP and HPI were showed in hepatic segment 3 compared to segment 4 (p = 0.000 and 0.000 respectively). No significant differences were found for THP among eight segments.

Conclusions

Intra-hepatic perfusion differences exist in normal hepatic parenchyma especially between lateral sector (segments 2 and 3) and right lobe (segments 5, 6, 7 and 8). This might have potential clinical significance in liver-perfusion-related protocol design and result analysis.