Role of CT and MRI prior to redo sternotomy in paediatric patients with congenital heart disease.

AIM: To assess the value of computed tomography (CT) and magnetic resonance imaging (MRI) in the preoperative evaluation of congenital heart disease patients about to undergo redo sternotomy. MATERIALS AND METHODS: Forty-three patients (26 male, 17 female, median age 65 months) underwent contrast-enhanced CT and 24 patients (16 male, eight female, median age 89 months) underwent MRI prior to redo sternotomy for congenital heart disease. The informed consent requirement was waived by the institutional review board for this Health Insurance Portability and Accountability Act (HIPAA) compliant study. A standardized CT protocol utilizing a 64 section multidetector machine and an unenhanced and contrast-enhanced MRI multisequence protocol was used. Images were qualitatively graded and retrosternal distances were measured as part of a risk assessment score. RESULTS: There were no statistically significant differences between the observers' grades regarding most retrosternal structures at both CT and MRI, separately (p > 0.05); furthermore, both readers found CT to be superior to MRI in qualitative grading except one reader's grades for shunts/conduits (p = 0.107). κ-values were good to excellent (κ ≥ 0.61) for most structures in qualitative grading of cases and risk assessment scores. There were no significant differences between grades of important structures using the same technique based on Friedman's test (p > 0.05). Analysis showed no difference between risk scores given to CT and MRI patients (p > 0.05). CONCLUSION: The present findings demonstrate the value of imaging to evaluate retrosternal anatomy. CT could be more valuable than MRI and could play a pivotal role in the surgical planning of CHD patients prior to redo operations.

Comprehensive low-dose imaging of carotid and coronary arteries with a single-injection dual-source CT angiography protocol.

AIM: To assess the feasibility of a fast single-bolus combined carotid and coronary computed tomography angiography (CTA) protocol in asymptomatic patients. MATERIALS AND METHODS: Thirty-three consecutive patients (18 women and 15 men) with a median age of 61 ± 14 years old (range 37-87 years) with known or suspected atherosclerotic disease were enrolled in this prospective study. A single breath-hold, single biphasic injection protocol (50 ml at 3 ml/s, 50 ml at 5 ml/s, 50 ml saline flush at 5 ml/s) was used for combined CTA imaging of the supra-aortic (SAA) and coronary arteries (CA) on a 64-slice dual-source CT (DSCT) machine. Helical CTA acquisition of the SAA was followed by prospective electrocardiography (ECG)-triggered coronary CTA. Subjective (four-point scale) image quality and objective signal-to-noise (SNR) and contrast-to-noise (CNR) measurements were performed. Vascular disease was graded on a four-point scale (grade 1: absent; grade 2: mild, grade 3: moderate; grade 4: severe). The radiation dose was recorded for each patient. RESULTS: The average enhancement and subjective quality score of SAA and CA segments were 396 HU/358 HU and 1.2 ± 0.3/1.72 ± 0.4, respectively. The SNR was 27.1 ± 1.7 in the SAA and 21.6 ± 1.6 in the CA (p < 0.0001). The CNR was 18.1 ± 1.2 and 15.9 ± 1.8, respectively (p = 0.4). Four percent of SAA and 14% of CA segments (mostly due to peri-venous streak artefacts and small calibre, respectively) produced non-diagnostic images. SAA findings were as follows: 26/33 (79%) patients showed no disease and 6/33 (18%) had grade 2 and 1/33 (3%) had grade 3 disease. CA findings were as follows: 25/33 (76%) showed no disease and 6/33 (18%) patients had grade 2 and 2/33 (6%) had grade 3 disease. Five patients had disease in both districts. The average radiation dose for the combined CTA angiogram was 4.3 ± 0.6 mSv. CONCLUSION: A fast, low-dose combined DSCT angiography protocol appears technically feasible for imaging carotid and coronary atherosclerotic disease.

Cardiac dual-source CT for the preoperative assessment of patients undergoing bariatric surgery.

AIM: To assess the diagnostic value of coronary dual-source computed tomography (DSCT) as a comprehensive, non-invasive tool in the preoperative cardiac evaluation of patients undergoing bariatric surgery. MATERIALS AND METHODS: Thirty consecutive obese [average body mass index (BMI): 45 ± 7.6, range: 35-59] patients (24 women; six men; median age: 52 ± 15 years) were enrolled in this institutional review board (IRB)-approved, Health Insurance Portability and Accountability Act of 1996 (HIPAA)-compliant prospective study. Calcium scoring (CaS) and electrocardiography (ECG)-gated images of the coronary arteries were obtained with a large body habitus protocol (120 kV; 430 mAs; 100 ml iodinated contrast medium at 7 ml/s injection rate) on a DSCT machine. Qualitative (four-point: 1 = excellent to 4 = not delineable) coronary segmental analysis, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) measurements were performed. The presence and degree of vascular disease (four-grade scale: mild to severe) was correlated with CaS and cardiovascular (CV) risk stratification blood tests. In patients with severe stenosis (>70%), findings were compared with cardiac nuclear medicine imaging (single photon-emission computed tomography; SPECT) imaging. RESULTS: The average HR, enhancement, and quality score were 64 ± 7 beats/min, 288 ± 66 HU and 1.8 ± .5, respectively. Ninety-three percent (417/450) of the coronary segments were rated diagnostic. The SNRs and CNRs were 17 ± 9 and 12 ± 7 for the right coronary artery; 17 ± 8 and 12 ± 7 for the left main coronary artery; 16 ± 9 and 11 ± 7 for the left anterior descending coronary artery; and 15 ± 7 and 10 ± 6 for the left circumflex coronary artery. Ten of the 30 patients (33%) demonstrated coronary artery disease (CAD) of which two (6%) showed three-vessel disease. Four (13%) patients showed severe disease: in three of which the presence of significant stenosis was confirmed by SPECT and by catheter angiography in the fourth patient. Neither the CaS, nor the CV risk stratification tests showed significant correlation with presence or degree of CAD (p > 0.05). CONCLUSIONS: Coronary DSCT is a robust alternative imaging tool in the preoperative assessment of patients undergoing bariatric surgery.

Standardisation of liver MDCT by tracking liver parenchyma enhancement to trigger imaging.

OBJECTIVE: To assess parenchymal bolus-triggering in terms of liver enhancement, lesion-to-liver conspicuity and inter-image variability across serial follow-up MDCTs. METHODS: We reviewed MDCTs of 50 patients with hepatic metastases who had a baseline CT and two follow-up examinations. In 25 consecutive patients CT data acquisition was initiated by liver parenchyma triggering at a 50-HU enhancement threshold. In a matched control group, imaging was performed with an empirical delay of 65 s. CT attenuation values were assessed in vessels, liver parenchyma and metastasis. Target lesions were classified according to five enhancement patterns. RESULTS: Compared with the control group, liver enhancement was significantly higher with parenchyma triggering (59.8 ± 7.6 HU vs. 48.8 ± 11.2 HU, P = 0.0002). The same was true for conspicuity (liver parenchyma - lesion attenuation) of hypo-enhancing lesions (72.2 ± 15.9 HU vs. 52.7 ± 19.4 HU, P = 0.0006). Liver triggering was associated with reduced variability for liver enhancement among different patients (P = 0.035) and across serial follow-up examinations in individual patients (P < 0.0001). The number of patients presenting with uniform lesion enhancement pattern across serial examinations was significantly higher in the triggered group (20 vs. 11; P = 0.018). CONCLUSION: Liver parenchyma triggering provides superior lesion conspicuity and improves standardisation of image quality across follow-up examinations with greater uniformity of enhancement patterns. KEY POINTS: Liver parenchyma tracking improves liver enhancement and lesion-to-liver conspicuity in abdominal CT. In serial CT studies this technique reduces variability of conspicuity and enhancement patterns. Higher liver-to-lesion conspicuity is a prerequisite for reliable detection of liver lesions. Stabilisation of enhancement permits more accurate follow-up of oncology patients.

Agenesis of the corpus callosum in fetuses with mild ventriculomegaly: role of MR imaging.

PURPOSE: We evaluated the role of magnetic resonance (MR) imaging in the diagnosis of corpus callosum agenesis - isolated or associated with other anomalies - in fetuses with mild cerebral ventriculomegaly, as depicted at prenatal sonography. MATERIAL AND METHODS: Between January 2005 and March 2007, 33 fetuses with a mean gestational age of 28.9 weeks (range 17-37) and mild ventriculomegaly diagnosed at prenatal sonography were included in this prospective study. All fetuses underwent MR imaging according to the following protocol: half-Fourier T2-weighted images along the three orthogonal plane according to the longitudinal axis of the mother, and subsequently three orthogonal planes were acquired according to the fetal brain. Quantitative image analysis included the size of the transverse diameter of the lateral ventricles, in the axial plane, and the thickness of the adjacent cerebral cortex. Qualitative image analysis included morphology of the lateral ventricles (normal, parallel pattern colpocephaly), signal intensity changes of the fetal brain, interruption of the germinative matrix, agenesis of the corpus callosum (complete/partial) and associated malformations. Postnatal physical examination and diagnostic imaging, as well as surgery, were the standard of diagnosis. RESULTS: Mean axial diameter of the lateral ventricle was 11.6 mm (range 10-15 mm), and mean thickness of the adjacent cerebral cortex was 2.1 mm (range 1.8-3 mm); 23/33 fetuses (70%) showed normal morphology of the lateral ventricles, and 8/33 (24%) showed abnormal morphology (parallel pattern, colpocephaly). The entire corpus callosum was visualised in 20/33 fetuses (60%). In 8/33 fetuses (25%), partial agenesis was diagnosed, whereas in 5/33 (15%), there was hypogenesis. In 6/13 fetuses (46%), isolated corpus callosum agenesis was detected, and two cases of hypogenesis of the corpus callosum were misinterpreted - overestimated in one case and underestimated in another. CONCLUSIONS: MR imaging may prove to be a useful second-line imaging modality in the prenatal diagnosis of corpus callosum agenesis in fetuses with mild ventriculomegaly.

Recurrent uterine cancer after surgery: magnetic resonance imaging patterns and their changes after concomitant chemoradiation.

PURPOSE: Our primary objective was to describe the magnetic resonance (MR) imaging patterns of recurrent uterine cancer after surgery and their changes following concurrent chemoradiation. The secondary objective was to identify MR imaging predictors of outcome. MATERIALS AND METHODS: Twenty-two consecutive women with biopsy-proven recurrent uterine cancer after surgery (cervix 13 patients, endometrium nine patients) were enrolled in this prospective study. Inclusion criteria were MR imaging at diagnosis and during follow-up and eligibility for concurrent chemoradiation. MR images were assessed for signal intensity of the pelvic relapse on T2-weighted images, site of relapse and infiltration of adjacent organs. Pre- and posttreatment MR images were compared on the basis of the same criteria. The 3D volume of relapses after treatment was calculated, and tumour response to treatment was evaluated as complete, partial, no change or disease progression. RESULTS: Recurrences appeared hyperintense on T2-weighted images in 22/22 (100%) patients. Pelvic relapse site was vagina in 5/22 (23%), vaginal vault in 9/22 (41%), vaginal vault with extension to the pelvic wall in 5/22 (23%) and pelvic wall in 3/22 (13%). Infiltration of adjacent organs was detected in 9/22 (41%) patients. The mean volume of recurrences on pretreatment MR images was 38.83 cm(3). On posttreatment MR images, relapses appeared hypointense in 19/22 (86%) patients and hyperintense in 3/22 (14%). The mean volume of recurrences on posttreatment MR images was 18.01 cm(3). Complete response was seen in 11/22 (50%) patients, partial response in 8/22 (36%) and no change in 3/22 (14%). CONCLUSIONS: MR imaging can provide an evaluation of all parameters necessary for planning treatment and assessing response to treatment.