A meta-analysis of ¹⁸FDG-PET-CT, ¹⁸FDG-PET, MRI and bone scintigraphy for diagnosis of bone metastases in patients with lung cancer

Background and purpose

Lung cancer is the most common cause of cancer related death among both men and women worldwide. The skeleton is the most common site of cancer metastasis. Early detection is crucial for prognosis. To evaluate and compare the capability for bone metastasis assessment of [¹⁸F] fluoro-2-d-glucose positron emission tomography with computed tomography (¹⁸FDG-PET–CT), [¹⁸F] fluoro-2-d-glucose positron emission tomography (¹⁸FDG-PET), magnetic resonance imaging (MRI) and bone scintigraphy (BS) in lung cancer patients, a meta-analysis is preformed.

Methods

We searched MEDLINE, OVID, EMBASE and the Cochrane Library for studies evaluating diagnosis validity of ¹⁸FDG-PET–CT, ¹⁸FDG-PET, MRI and BS between January 1990 and August 2010. Meta-analysis methods were used to pool sensitivity, specificity, diagnostic odd ratios (DORs) and to construct a summary receiver-operating characteristic curve (SROC).

Results

A total of 17 articles (9 ¹⁸FDG-PET–CT studies, 9 ¹⁸FDG-PET studies, 6 MRI studies and 16 BS studies) that included 2940 patients who fulfilled all of the inclusion criteria were considered for inclusion in the analysis. The pooled sensitivity for the detection of bone metastasis in lung cancer using ¹⁸FDG-PET–CT, ¹⁸FDG-PET, MRI and BS were 0.92 (95% CI, 0.88–0.95), 0.87 (95% CI, 0.81–0.92), 0.77 (95% CI, 0.65–0.87) and 0.86 (95% CI, 0.82–0.89), respectively. The pooled specificity for the detection of bone metastasis from lung cancer using ¹⁸FDG-PET–CT, ¹⁸FDG-PET, MRI and BS were 0.98 (95% CI, 0.97–0.98), 0.94 (95% CI, 0.92–0.96), 0.92 (95% CI, 0.88–0.95), 0.88 (95% CI, 0.86–0.89), respectively. The pooled DORs estimates for ¹⁸FDG-PET–CT 449.17 were significantly higher than for ¹⁸FDG-PET (118.25, P < 0.001), MRI (38.27, P < 0.001) and BS (63.37, P < 0.001). The pooled sensitivity of BS was not correlated with the prevalence of bone metastasis.

Conclusion

The results showed that both ¹⁸FDG-PET–CT and ¹⁸FDG-PET were better imaging methods for diagnosing bone metastasis from lung cancer than MRI and BS. ¹⁸FDG-PET–CT has higher diagnostic value (sensitivity, specificity and DORs) for diagnosing bone metastasis from lung cancer than any other imaging methods.     

Non-invasive assessment of congenital pulmonary vein stenosis in children using cardiac-non-gated CT with 64-slice technology

Background

Management of congenital pulmonary vein stenosis is a diagnostic challenge. Echocardiography may be insufficient and thus cardiac catheterization remains the reference standard in this setting. The aim of the study was to investigate the accuracy of cardiac-non-gated CT using 64-slice technology in detecting congenital pulmonary vein stenosis in children.

Materials and methods

CT examinations were consecutively performed from May 2005 to December 2006 in 13 children aged 1.5–12 months (median 5 months) for suspected congenital pulmonary vein stenosis. Cardiac-non-gated CT acquisitions were performed after the peripheral injection of contrast agent. Pulmonary veins were evaluated for their pattern of connectivity from the lung to the left atrium and for the presence of stenosis. CT findings of pulmonary vein stenosis were compared with combined findings available from echocardiography, catheterization and surgery.

Results

Pulmonary veins from the right lung (n = 29) and left lung (n = 26) were evaluated as separate structures (N = 55). Of the 55 structures, 32 had surgical and/or catheterization data and 45 had echocardiography for comparison. CT visualized 100% (55/55) of the investigated structures, while echocardiography visualized 82% (45/55). In the 13 subjects CT identified 10 stenotic pulmonary veins. CT confirmed the echocardiography suspicion of pulmonary vein stenosis in 100% (7/7) and established a new diagnosis in 3 other patients. CT agreed with surgery/catheterization in 100% (10/10) of the available comparisons.

Conclusion

Cardiac-non-gated CT assessed the pulmonary veins more completely than echocardiography and should be considered as a viable alternative for invasive pulmonary venography for detecting pulmonary vein stenosis in children.     

Cancer patients and characteristics of pulmonary embolism

Objective

To check the hypothesis that cancer patients suffer from extended pulmonary embolism (PE) more frequently than patients without cancer we analysed PEs proved by computed tomography (CT)-imaging.

Patients and methods

One hundred and fifty consecutive CT scans at the University Hospital of Essen from March 2002 until December 2004 which proved a definite case of pulmonary embolism were retrospectively reviewed (79 men, 71 women; mean age 57 ± 15 years). Underlying disease and blood parameters were included (haemoglobin, haematocrit, fibrinogen and total protein, if determined within 48 h before the CT scans).

Results

Patients with malignant disease were older (59 ± 12 years vs. 54 ± 19 years, p = 0.05) and tend to have a higher rate of central PEs (52% vs. 34%, p = 0.08) than patients without malignancies. The odds of a central PE in cancer patients was about twice as high as in patients without a malignant disease (Odds ratio: 2.08, 95%-confidence interval: 1.06–4.10; age-adjusted Odds ratio 1.88, 95%-confidence interval: 0.92–3.84). Additional adjustment for the clinical information dyspnoea, inhospital patient and clinically expected PE did not deteriorate the odds. Thrombus density determined in patients with central PE only shows a trend towards a lower density in patients with malignant disease (52 ± 13 HE vs. 45 ± 15 HE, p = 0.13). There is no statistical evidence that thrombus density is related to one of the blood parameters or even blood density measured in the pulmonary artery.

Conclusion

Although this is a retrospective study including a small number of patients it shows that cancer patients are at a higher risk for central PE than patients without cancer. Characteristics of the intrapulmonal thrombus in cancer and non-cancer patients seem to be different.     

How accurate are measurements of skin-lesion depths on prebiopsy supine chest computed tomography for transthoracic needle biopsies?

Aim

To evaluate the accuracy of depth measurements on supine chest computed tomography (CT) for transthoracic needle biopsy (TNB).

Materials and methods

We measured skin-lesion depths from the skin surface to nodules on both prebiopsy supine CT scans and CT scans obtained during cone beam CT-guided TNB in the supine (n = 29) or prone (n = 40) position in 69 patients, and analyzed the differences between the two measurements, based on patient position for the biopsy and lesion location.

Results

Skin-lesion depths measured on prebiopsy supine CT scans were significantly larger than those measured on CT scans obtained during TNB in the prone position (p < 0.001; mean difference ± standard deviation (SD), 6.2 ± 5.7 mm; range, 0–18 mm), but the differences showed marginal significance in the supine position (p = 0.051; 3.5 ± 3.9 mm; 0–13 mm). Additionally, the differences were significantly larger for the upper (mean ± SD, 7.8 ± 5.7 mm) and middle (10.1 ± 6.5 mm) lung zones than for the lower lung zones (3.1 ± 3.3 mm) in the prone position (p = 0.011), and were larger for the upper lung zone (4.6 ± 5.0 mm) than for the middle (2.4 ± 2.0 mm) and lower (2.3 ± 2.3 mm) lung zones in the supine position (p = 0.004).

Conclusions

Skin-lesion depths measured on prebiopsy supine chest CT scans were inaccurate for TNB in the prone position, particularly for nodules in the upper and middle lung zones.     

Value of dual time point F-18 FDG-PET/CT imaging for the evaluation of prognosis and risk factors for recurrence in patients with stage I non-small cell lung cancer treated with stereotactic body radiation therapy

Purpose

To investigate prognostic and risk factors for recurrence after stereotactic body radiation therapy (SBRT) in patients with stage I non-small cell lung carcinoma (NSCLC), focusing on dual time point [18]F-fluorodeoxyglucose positron emission tomography (FDG PET).

Materials and methods

We prospectively evaluated 57 patients with stage I NSCLC (45 T1N0M0 and 12 T2N0M0) who had undergone pretreatment FDG-PET/CT and were subsequently treated with SBRT. All patients received a whole-body PET/CT scan at 60 min and a whole-lung at 120 min after the injection. The maximum standardized uptake value (SUV) and retention index (RI) of the lesions were calculated. Local recurrence, regional lymph node metastasis, distant metastasis, and the recurrence pattern were evaluated. Cox proportional hazard regression analyses were performed to evaluate prognostic factors or risk factors of recurrence.

Results

During the median follow-up period of 27 months, local recurrence, regional lymph node metastasis, and distant metastasis were seen in 17 (30%), 12 (21%), and 17 (30%) of the 57 patients, respectively. The 3-year overall survival rate was 63.4%. SUV_max did not affect any recurrence, DFS, OS, or CSS. RI significantly predicted higher distant metastasis (HR 47.546, p = 0.026). In contrast, RI tended to predict lower local recurrence (HR 0.175, p = 0.246) and regional lymph node metastasis (HR 0.109, p = 0.115).

Conclusions

SUV_max at staging FDG-PET does not predict any recurrence, DFS, OS or CSS. In contrast, higher RI predicts higher distant metastasis and tended to predict lower local or regional lymph node metastasis.     

Intraobserver and interobserver agreement of volume perfusion CT (VPCT) measurements in patients with lung lesions

Objectives

To evaluate intraobserver and interobserver agreement of manually encompassed lung lesions for perfusion measurements using volume-perfusion computed tomography (VPCT).

Materials and methods

Institutional review board approval and informed consent were obtained. HIPAA guidelines were followed. A 65-s dynamic study was acquired with scan parameters 80 kV, 60 mA s (80 mA s for patients ≥70 kg), 128 × 0.6 mm collimation. Blood flow (BF), blood volume (BV) and K^trans parameters were determined by syngo volume perfusion CT body with 88 lesions analyzed retrospectively.

Results

Within-subject coefficients of variation for intraobserver agreement (range 6.59–12.82%) were superior to those for interobserver agreement (range 21.75–38.30%). Size-dependent analysis revealed lower agreements for lesions <4 cm as compared to larger lesions. Additionally, agreements of the upper, middle and lower lung zones were different.

Conclusions

Intraobserver agreement was substantial for VPCT lung cancer perfusion measurements encouraging the use for tumor characterization and therapy response monitoring. Interobserver agreement is limited and unexperienced readers should be trained before using this new method.     

Computed tomography findings from patients with ARDS due to Influenza A (H1N1) virus-associated pneumonia

Purpose

The purpose of this study was to retrospectively evaluate whether computed tomography (CT) findings have prognostic value for the prediction of mortality and severity of the clinical course in patients presenting with early stage of acute respiratory distress syndrome (ARDS) due to swine-origin influenza A (S-OIV).

Materials and methods

Chest CT (16-/64-row multidetector CT) of 23 patients (of whom 9 patients died) were retrospectively reviewed by three independent blinded observers. The CT findings were graded on a 3-point scale (1: normal attenuation, 2: ground-glass attenuation, 3: consolidation). The extent of each abnormality was determined by visually estimating the percentage (to the nearest 10%) of the affected lung parenchyma in each zone and multiplied by the CT-score described above.

Results

All patients presented with a mixture of bilateral patchy consolidations and ground glass opacities. Spearman rank correlation in evaluation of the presence and extent of lung abnormalities by the three different observers was good (correlation coefficient, 0.876–0.922; p < 0.001). The overall CT-score in survivors (mean, 96.0 (±26.2); range, 53–158) was significantly lower than that in non-survivors (mean, 116.2 (±14.0); range, 101–139). ROC analysis revealed an area under curve of 0.79 (p = 0.021) for the CT score with an optimal cutoff value of a CT-score of 100 for prediction of survival, with a sensitivity of 100% and a specificity of 64% (accuracy, 78%). For this optimal cutoff, Kaplan–Meier estimator showed a significant difference for the survival ratio (p = 0.011).

Conclusion

In patients with severe ARDS due to S-OIV-infection, the CT-score has a prognostic value in the prediction of mortality.     

PET/CT scanning guided intensity-modulated radiotherapy in treatment of recurrent ovarian cancer

Objective

This study was undertaken to evaluate the clinical contribution of positron emission tomography using ¹⁸F-fluorodeoxyglucose and integrated computer tomography (FDG-PET/CT) guided intensity-modulated radiotherapy (IMRT) for treatment of recurrent ovarian cancer.

Materials and methods

Fifty-eight patients with recurrent ovarian cancer from 2003 to 2008 were retrospectively studied. In these patients, 28 received PET/CT guided IMRT (PET/CT–IMRT group), and 30 received CT guided IMRT (CT–IMRT group). Treatment plans, tumor response, toxicities and survival were evaluated.

Results

Changes in GTV delineation were found in 10 (35.7%) patients based on PET–CT information compared with CT data, due to the incorporation of additional lymph node metastases and extension of the metastasis tumor. PET/CT guided IMRT improved tumor response compared to CT–IMRT group (CR: 64.3% vs. 46.7%, P = 0.021; PR: 25.0% vs. 13.3%, P = 0.036). The 3-year overall survival was significantly higher in the PET–CT/IMRT group than control (34.1% vs. 13.2%, P = 0.014).

Conclusions

PET/CT guided IMRT in recurrent ovarian cancer patients improved the delineation of GTV and reduce the likelihood of geographic misses and therefore improve the clinical outcome.     

The low attenuation area on dual-energy perfusion CT: correlation with the pulmonary function tests and quantitative CT measurements

Purpose

To retrospectively investigate the distribution of the low attenuation area (LAA) on dual energy perfusion CT (DEpCT) in comparison with the results of pulmonary function tests (PFTs) and quantitative CT measurements.

Materials and methods

Twenty-eight patients (15 male and 13 female; mean age: 62.21 years) underwent DEpCT and PFTs within a 1-month interval. The ranges of the LAA on DEpCT were classified into six groups with attenuation values of 0–3, 0–5, 0–8, 0–10, 0–13 and 0–15 HU and the ratios of LAA in each group were compared with the percentage of forced expiratory volume in the 1st second (%FEV_1.0), FEV_1.0/forced vital capacity (FEV_1.0/FVC) and the relative area of the lung with attenuation coefficients lower than −950 HU (RA₋₉₅₀).

Results

The LAAs on the DEpCT images were significantly correlated with the RA₋₉₅₀, %FEV_1.0 and FEV_1.0/FVC, and the regression analysis showed that the best values of LAA on DEpCT were 0–10 HU with RA₋₉₅₀ (r = 0.63), 0–8 HU with %FEV_1.0 (r = −0.52) and 0–8 HU with FEV_1.0/FVC (r = −0.61) per patient.

Conclusion

The iodine disturbance on DEpCT had a moderate correlation with the results of the PFTs and RA₋₉₅₀, but further examination would be needed for evaluation of iodine distribution.     

Intermodality comparison between 3D perfusion CT and 18F-FDG PET/CT imaging for predicting early tumor response in patients with liver metastasis after chemotherapy: Preliminary results of a prospective study

Objectives

To evaluate the feasibility of 3D perfusion CT for predicting early treatment response in patients with liver metastasis from colorectal cancer.

Methods

Seventeen patients with colon cancer and liver metastasis were prospectively enroled to undergo perfusion CT and 18F-FDG-PET/CT before and after one-cycle of chemotherapy. Two radiologists and three nuclear medicine physicians measured various perfusion CT and PET/CT parameters, respectively from the largest hepatic metastasis. Baseline values and reduction rates of the parameters were compared between responders and nonresponders. Spearman correlation test was used to correlate perfusion CT and PET/CT parameters, using RECIST criteria as reference standard.

Results

Nine patients responded to treatment, eight patients were nonresponders. Baseline SUV_mean30 on PET/CT, reduction rates of 30% metabolic volume and 30% lesion glycolysis (LG₃₀) on PET/CT and blood flow (BF) and flow extraction product (FEP) on perfusion CT after chemotherapy were significantly different between responders and nonresponders (P = 0.008–0.046). Reduction rates of BF (correlation coefficient = 0.630) and FEP (correlation coefficient = 0.578) significantly correlated with that of LG₃₀ on PET/CT (P < 0.05).

Conclusion

CT perfusion parameters including BF and FEP may be used as early predictors of tumor response in patients with liver metastasis from colorectal cancer.     

X-ray induced DNA double-strand breaks in coronary CT angiography: comparison of sequential, low-pitch helical and high-pitch helical data acquisition

Background

Aim of this study was to compare DNA double-strand breaks (DSBs) in blood lymphocytes of patients undergoing high-pitch helical, low-pitch helical and sequential coronary CT angiography.

Methods and results

66 patients were examined with various scan protocols and modes (low-pitch helical scan: 100–120 kV, 320–438 mAs/rot, pitch 0.18–0.39, with or without ECG-pulsing, n = 35; prospectively ECG-triggered high-pitch helical scan: 100–120 kV, 320–456 mAs/rotation, pitch 3.2–3.4, n = 19; prospectively ECG-triggered sequential scan: 100–120 kV, 150–300 mAs or 320–370 mAs/rotation, n = 12) either using a 64-slice or 128-slice dual-source CT or a 128-slice single source CT scanner. Blood samples were obtained before and 30 min after CT and DSBs were analyzed in isolated lymphocytes using γ-H2AX immunofluorescence microscopy.A significant increase of DSBs was measurable 30 min after CTA (range 0.01–0.71/cell). CT induced DSBs showed a significant correlation with the estimated effective dose (ρ = 0.90, p < 0.00001). Both prospectively ECG-triggered sequential (0.10 DSBs/cell, 176 mGy cm, p < 0.00001) and high-pitch helical scan protocols (0.03 DSBs/cell, 109 mGy cm, p < 0.00001) led to a significant reduction of median DLP and DSB levels compared to low-pitch helical scans (0.34 DSBs/cell, 828 mGy cm). A reduction of the tube voltage resulted in significantly lower whereas additional calcium scoring resulted in elevated DLP and DNA damages (p < 0.05 each).

Conclusion

In coronary CTA, data acquisition protocols have a significant influence on the X-ray induced DSB levels. Using γ-H2AX immunofluorescence microscopy different scan modes in different CT generations can be compared concerning their biological impact.     

Ventricular short-axis measurements in patients with pulmonary embolism: effect of ECG-gating on variability, accuracy, and risk prediction

Objective

To assess prospectively the intra- and interobserver variability, accuracy, and prognostic value of right and left ventricular short-axis diameter (RVd and LVd) measurements for risk stratification in patients with pulmonary embolism (PE) using ECG-gated compared to non-gated CT.

Materials and methods

Sixty consecutive patients (33 women; mean age 58.7 ± 10.3 years) with suspicion of PE underwent both non-gated and ECG-gated chest CT. RVd and LVd on four-chamber views and intra- and interobserver agreements were calculated for both protocols. RVd/LVd ratios were calculated and were related to 30-days adverse clinical events using receiver operating characteristics with area-under-the-curve (AUC) analyses.

Results

Both inter- and intraobserver variability showed narrower limits of agreement for all measurements with ECG-gated as compared to non-gated CT. Diameter measurements were significantly lower using non-ECG-gated CT as compared to ECG-gated CT for RVd and LVd (both p < .05). The AUC for the RVd/LVd ratio from ECG-gated CT was significantly larger than that from non-gated CT (0.956, 95% CI: 0.768–0.999 versus 0.675, 95% CI: 0.439–0.860; p = .048).

Conclusion

RVd and LVd measurements from ECG-gated chest CT show less intra- and interobserver variability and more accurately reflect ventricular function. In our patient cohort ECG-gated chest CT allows better prediction of short-term outcome of patients with acute PE that needs to be validated in a larger outcome study.     

Hepatic arterial perfusion increases in the early stage of severe acute pancreatitis patients: evaluation by perfusion computed tomography

Purpose

Although hepatic perfusion abnormalities have been reported in patients with acute pancreatitis, hepatic perfusion with severe acute pancreatitis (SAP) has not been quantitatively evaluated in humans. Therefore, we investigated hepatic perfusion in patients with SAP using perfusion CT.

Materials and methods

Hepatic perfusion CT was performed in 67 patients with SAP within 3 days after symptom onset. The patients were diagnosed as having SAP according to the Atlanta criteria. Fifteen cases were established as a control group. Perfusion CT was obtained for 54 s beginning with a bolus injection of 40 ml of contrast agent (600–630 mgI/kg) at a flow rate of 4 ml/s. Perfusion data were analyzed by the dual-input maximum slope method to obtain hepatic arterial perfusion (HAP) and hepatic portal perfusion (HPP). Finally, we compared HAP and HPP in SAP patients with those in the control group, respectively.

Results

Average HAP was significantly higher in SAP patients than in the control group (75.1 ± 38.0 vs. 38.2 ± 9.0 ml/min/100 ml; p < 0.001). There was no significant difference in average HPP between SAP patients and the control group (206.7 ± 54.9 vs. 204.4 ± 38.5 ml/min/100 ml; p = 0.92).

Conclusion

Using quantitative analysis on perfusion CT, we first demonstrated an increase of HAP in the right hepatic lobe in SAP patients.     

Cost reduction in abdominal CT by weight-adjusted dose

Aim

To analyze the influence of contrast dose adjusted by weight vs. fixed contrast dose in the attenuation and cost of abdominal computed tomography (CT).

Materials and methods

A randomised, consecutive, parallel group study was conducted in 151 patients (74 men and 77 women, age range 22–67 years), studied with the same CT helical protocol. A dose at 1.75 ml/kg was administered in 101 patients while 50 patients had a fixed dose of 120 ml of same non-ionic contrast material (320 mg/ml). Mean enhancements were measured at right hepatic lobe, superior abdominal aorta and inferior cava vein. Statistical analysis was weight-stratified (<60, 61–70, 71–80 and >81 kg).

Results

Aortic attenuation was significantly superior (p < 0.05) in the dose adjusted by weight group than in the fixed dose group. Patients who weighed >61 kg in dose-adjusted group, presented higher hepatic attenuation, being statistically significant in those >81 kg (p < 0.01). In dose-adjusted group, there was a savings of €4.1 per patient in patients weighing <80 kg. In patients weighing >80 kg, there was an over cost of €10.7 per patient.

Conclusions

An injection volume of 1.75 ml/kg offers an optimal diagnostic quality with a global savings of €1.34 per patient.     

Breast cancer with low FDG uptake: characterization by means of dual-time point FDG-PET/CT

Background

Malignant breast lesions usually are differentiated by FDG-PET with a semiquantitative FDG standardized uptake value (SUV) of 2.5. However, the frequency of breast cancer with an SUV of less than or equal to 2.5 is noteworthy, and often present diagnostic challenges. This study was undertaken to evaluate the accuracy of dual-time point FDG-PET/CT with FDG standardized uptake value (SUV) calculation in the characterization of such breast tumors.

Methods

Forty-nine female patients with newly diagnosed breast cancer were found to have primary breast cancer with minimally increased FDG uptake and met the criteria for inclusion in this study by having borderline levels of increased FDG uptake (SUVmax less than or equal to 2.5) in the initial FDG-PET/CT images. Consequently, they underwent further delayed phase FDG-PET/CT scan for better evaluation of the disease.

Results

Of the 49 cancer lesions; the majority were found to have rising or unvarying dual-time changes in SUVmax (75.5%). The median value of SUVmax increases by 25% between the early and delayed scan. The means ± S.D. of the SUVmax1, the SUVmax2, and the ΔSUVmax% were 1.2 ± 0.6%, 1.3 ± 0.9%, and 5.1 ± 22.4%, respectively. The receiver-operating-characteristic (ROC) analysis proved that the highest accuracy for characterization of malignant breast lesions was obtained when a ΔSUVmax% cut-off value 0.0% was used as criteria for malignant FDG uptake-change over time with sensitivity 75.5%, and false-positive rate 20.4%.

Conclusion

These results suggested that dual-time FDG-PET/CT imaging with standardized uptake value (SUV) estimation can improve the accuracy of the test in the evaluation of breast cancer with low FDG uptake.     

Virtual non-contrast in second-generation, dual-energy computed tomography: reliability of attenuation values

Purpose

To evaluate the reliability of attenuation values in virtual non-contrast images (VNC) reconstructed from contrast-enhanced, dual-energy scans performed on a second-generation dual-energy CT scanner, compared to single-energy, non-contrast images (TNC).

Materials and methods

Sixteen phantoms containing a mixture of contrast agent and water at different attenuations (0–1400 HU) were investigated on a Definition Flash-CT scanner using a single-energy scan at 120 kV and a DE-CT protocol (100 kV/SN140 kV). For clinical assessment, 86 patients who received a dual-phase CT, containing an unenhanced single-energy scan at 120 kV and a contrast enhanced (110 ml Iomeron 400 mg/ml; 4 ml/s) DE-CT (100 kV/SN140 kV) in an arterial (n = 43) or a venous phase, were retrospectively analyzed. Mean attenuation was measured within regions of interest of the phantoms and in different tissue types of the patients within the corresponding VNC and TNC images. Paired t-tests and Pearson correlation were used for statistical analysis.

Results

For all phantoms, mean attenuation in VNC was 5.3 ± 18.4 HU, with respect to water. In 86 patients overall, 2637 regions were measured in TNC and VNC images, with a mean difference between TNC and VNC of −3.6 ± 8.3 HU. In 91.5% (n = 2412) of all cases, absolute differences between TNC and VNC were under 15 HU, and, in 75.3% (n = 1986), differences were under 10 HU.

Conclusions

Second-generation dual-energy CT based VNC images provide attenuation values close to those of TNC. To avoid possible outliers multiple measurements are recommended especially for measurements in the spleen, the mesenteric fat, and the aorta.     

Treatment response assessment of radiofrequency ablation for hepatocellular carcinoma: usefulness of virtual CT sonography with magnetic navigation

Purpose

Virtual CT sonography using magnetic navigation provides cross sectional images of CT volume data corresponding to the angle of the transducer in the magnetic field in real-time. The purpose of this study was to clarify the value of this virtual CT sonography for treatment response of radiofrequency ablation for hepatocellular carcinoma.

Patients and methods

Sixty-one patients with 88 HCCs measuring 0.5–1.3 cm (mean ± SD, 1.0 ± 0.3 cm) were treated by radiofrequency ablation. For early treatment response, dynamic CT was performed 1–5 days (median, 2 days). We compared early treatment response between axial CT images and multi-angle CT images using virtual CT sonography.

Results

Residual tumor stains on axial CT images and multi-angle CT images were detected in 11.4% (10/88) and 13.6% (12/88) after the first session of RFA, respectively (P = 0.65). Two patients were diagnosed as showing hyperemia enhancement after the initial radiofrequency ablation on axial CT images and showed local tumor progression shortly because of unnoticed residual tumors. Only virtual CT sonography with magnetic navigation retrospectively showed the residual tumor as circular enhancement. In safety margin analysis, 10 patients were excluded because of residual tumors. The safety margin more than 5 mm by virtual CT sonographic images and transverse CT images were determined in 71.8% (56/78) and 82.1% (64/78), respectively (P = 0.13). The safety margin should be overestimated on axial CT images in 8 nodules.

Conclusion

Virtual CT sonography with magnetic navigation was useful in evaluating the treatment response of radiofrequency ablation therapy for hepatocellular carcinoma.     

Meta-analysis: serum creatinine changes following contrast enhanced CT imaging

Purpose

Contrast induced nephropathy (CIN) is defined as a decrease in renal function following administration of contrast media. The aim of this meta-analysis was to asses the overall risk of CIN, chronic loss of kidney function and the need for renal replacement therapy (RRT) after intravenous contrast enhanced CT-scan. Secondly, we aimed to identify subgroups at increased risk for CIN.

Materials and methods

A literature search in Pubmed, Medline, Embase and Cochrane databases was performed. Data extraction was carried out independently by two reviewers. Meta-analysis and meta-regression were performed using an exact likelihood approach.

Results

Forty studies evaluating the incidence of CIN after CT were included. The pooled incidence of CIN was 6.4% (95% CI 5.0–8.1). The risk of RRT after CIN was low, 0.06% (95% CI 0.01–0.4). The decline in renal function persisted in 1.1% of patients (95% CI 0.6–2.1%). Patients with chronic kidney disease (odds ratio 2.26, p < 0.001) or diabetes mellitus (odds ratio 3.10, p < 0.001) were at increased risk for the development of CIN.

Conclusion

CIN occurred in 6% of patients after contrast enhanced CT. In 1% of all patients undergoing contrast enhanced CT the decline in renal function persisted.     

Dose modulated retrospective ECG-gated versus non-gated 64-row CT angiography of the aorta at the same radiation dose: comparison of motion artifacts, diagnostic confidence and signal-to-noise-ratios

Purpose

To compare ECG-gated and non-gated CT angiography of the aorta at the same radiation dose, with regard to motion artifacts (MA), diagnostic confidence (DC) and signal-to-noise-ratios (SNRs).

Materials and methods

Sixty consecutive patients prospectively randomized into two groups underwent 64-row CT angiography, with or without dose-modulated ECG-gating, of the entire aorta, due to several pathologies of the ascending aorta. MA and DC were both assessed using a four-point scale. SNRs were calculated by dividing the mean enhancement by the standard deviation. The dose-length-product (DLP) of each examination was recorded and the effective dose was estimated.

Results

Dose-modulated ECG-gating showed statistically significant advantages over non-gated CT angiography, with regard to MA (p < 0.001) and DC (p < 0.001), at the aortic valve, at the origin of the coronary arteries, and at the dissection membrane, with a significant correlation (p < 0.001) between MA and DC. At the aortic wall, however, ECG-gated CT angiography showed statistically significant fewer MA (p < 0.001), but not a statistically significant higher DC (p = 0.137) compared to non-gated CT angiography. At the supra-aortic vessels and the descending aorta, the ECG-triggering showed no statistically significant differences with regard to MA (p = 0.861 and 0.526, respectively) and DC (p = 1.88 and 0.728, respectively). The effective dose of ECG-gated CT angiography (23.24 mSv; range, 18.43–25.94 mSv) did not differ significantly (p = 0.051) from that of non-gated CT angiography (24.28 mSv; range, 19.37–29.27 mSv).

Conclusion

ECG-gated CT angiography of the entire aorta reduces MA and results in a higher DC with the same SNR, compared to non-gated CT angiography at the same radiation dose.     

Utility of the broccoli sign in the distinction of prolapsed uterine tumor from cervical tumor

Objective

To describe the utility, histopathological basis, and clinical correlates of the broccoli sign.

Methods

The committee on human research approved this HIPAA compliant study and waived written informed consent. Based on the records of the senior author and our multidisciplinary Gynecologic Oncology Tumor Board, we retrospectively identified thirteen women (mean age of 48.8 years; range, 34–74) with a cervical mass seen at MR imaging (n = 13) or CT (n = 5) that demonstrated the previously reported broccoli sign (i.e., a soft tissue stalk connecting the cervical mass to the uterine cavity) on one or other modality. All available clinical, imaging, and histopathological records were reviewed, with particular emphasis on initially suspected diagnosis, final proven diagnosis, and outcome.

Results

Cervical cancer was the initial clinically suspected diagnosis in 6 of 13 patients. Surgical resection demonstrated prolapsed uterine tumor in all patients, consisting of endometrioid adenocarcinoma (n = 7), carcinosarcoma (n = 2), adenosarcoma (n = 1), and leiomyoma (n = 3). Excluding the three patients with leiomyomas, currently, 7 patients with malignant tumors are disease free after a mean interval of 15 months (range, 3–45) and 3 patients have been lost to follow-up.

Conclusion

A stalk connecting an apparent cervical mass seen at CT or MR imaging to the endometrial cavity (“broccoli sign”) favors the diagnosis of a prolapsed uterine tumor; these prolapsed uterine tumors can often be malignant but appear to have a good prognosis.