Microwave ablation assisted by a real-time virtual navigation system for hepatocellular carcinoma undetectable by conventional ultrasonography

Objectives

To evaluate the efficiency and feasibility of microwave (MW) ablation assisted by a real-time virtual navigation system for hepatocellular carcinoma (HCC) undetectable by conventional ultrasonography.

Methods

18 patients with 18 HCC nodules (undetectable on conventional US but detectable by intravenous contrast-enhanced CT or MRI) were enrolled in this study. Before MW ablation, US images and MRI or CT images were synchronized using the internal markers at the best timing of the inspiration. Thereafter, MW ablation was performed under real-time virtual navigation system guidance. Therapeutic efficacy was assessed by the result of contrast-enhanced imagings after the treatment.

Results

The target HCC nodules could be detected with fusion images in all patients. The time required for image fusion was 8–30 min (mean, 13.3 ± 5.7 min). 17 nodules were successfully ablated according to the contrast enhanced imagings 1 month after ablation. The technique effectiveness rate was 94.44% (17/18). The follow-up time was 3–12 months (median, 6 months) in our study. No severe complications occurred. No local recurrence was observed in any patients.

Conclusions

MW ablation assisted by a real-time virtual navigation system is a feasible and efficient treatment of patients with HCC undetectable by conventional ultrasonography.     

Comparison of imaging characteristics between hepatic benign regenerative nodules and hepatocellular carcinomas associated with Budd-Chiari syndrome by contrast enhanced ultrasound

Purpose

To compare different imaging characteristics between hepatic benign regenerative nodules and hepatocellular carcinomas (HCCs) associated with Budd–Chiari syndrome (BCS) by contrast enhanced ultrasound (CEUS).

Materials and methods

A total of 32 chronic BCS patients (mean age, 42 years; age range, 18–59 years) with hepatic nodules who underwent CEUS were retrospectively studied. All patients had no the history of viral hepatitis. There were 23 patients with benign regenerative nodules (22 ± 9 mm; range, 8–42 mm) and 9 patients with HCCs (63 ± 21 mm; range, 26–90 mm). Lesion characteristics, including number, size, vascularization on color Doppler flow imaging, echogenicity, peripheral hypoechoic rim, and enhancement patterns in arterial, portal, and late phases on CEUS, were analyzed.

Results

There were significant differences in number and size of the lesions between two groups. No significant differences were observed in vascularity, echogenicity, and peripheral hypoechoic rim. Overall, there were significant differences in enhancement patterns in arterial, portal, and late phases between them on CEUS. Of 23 patients with benign regenerative nodules, 16 (70%) were center-to-periphery hyperenhanced and 7 patients (30%) were homogeneously hyperenhanced in arterial phase; the majority were homogeneously hyperenhanced in portal and late phases. Of 9 patients with HCCs, 8 (89%) were heterogeneously hyperenhanced in arterial phase and most of them were hypoenhanced in portal and late phases.

Conclusion

CEUS imaging characteristics of benign regenerative nodules radically differ from that of HCCs in BCS patients.     

Comparison of temperature curve and ablation zone between 915- and 2450-MHz cooled-shaft microwave antenna: results in ex vivo porcine livers

Objective

To compare temperature curve and ablation zone between 915- and 2450-MHz cooled-shaft microwave antenna in ex vivo porcine livers.

Materials and methods

The 915- and 2450-MHz microwave ablation and thermal monitor system were used in this study. A total of 56 ablation zones and 280 temperature data were obtained in ex vivo porcine livers. The output powers were 50, 60, 70, and 80 W and the setting time was 600 s. The temperature curve of every temperature spot, the short- and long-axis diameters of the coagulation zones were recorded and measured.

Results

At all four power output settings, the peak temperatures of every temperature spot had a tendency to increase accordingly as the MW output power was increased, and except for 5 mm away from the antenna, the peak temperatures for the 915 MHz cooled-shaft antenna were significantly higher than those for the 2450 MHz cooled-shaft antenna (p < 0.05). Meanwhile, the short- and long-axis diameters for the 915 MHz cooled-shaft antenna were significantly larger than those for the 2450 MHz cooled-shaft antenna (p < 0.05).

Conclusion

The 915 MHz cooled-shaft antenna can yield a significantly larger ablation zone and achieve higher temperature in ablation zone than a 2450 MHz cooled-shaft antenna in ex vivo porcine livers.     

Role of baseline nodule density and changes in density and nodule features in the discrimination between benign and malignant solid indeterminate pulmonary nodules

Purpose

To retrospectively evaluate whether baseline nodule density or changes in density or nodule features could be used to discriminate between benign and malignant solid indeterminate nodules.

Materials and methods

Solid indeterminate nodules between 50 and 500 mm³ (4.6–9.8 mm) were assessed at 3 and 12 months after baseline lung cancer screening (NELSON study). Nodules were classified based on morphology (spherical or non-spherical), shape (round, polygonal or irregular) and margin (smooth, lobulated, spiculated or irregular). The mean CT density of the nodule was automatically generated in Hounsfield units (HU) by the Lungcare^© software.

Results

From April 2004 to July 2006, 7310 participants underwent baseline screening. In 312 participants 372 solid purely intra-parenchymal nodules were found. Of them, 16 (4%) were malignant. Benign nodules were 82.8 mm³ (5.4 mm) and malignant nodules 274.5 mm³ (8.1 mm) (p = 0.000). Baseline CT density for benign nodules was 42.7 HU and for malignant nodules −2.2 HU (p = ns). The median change in density for benign nodules was −0.1 HU and for malignant nodules 12.8 HU (p < 0.05). Compared to benign nodules, malignant nodules were more often non-spherical, irregular, lobulated or spiculated at baseline, 3-month and 1-year follow-up (p < 0.0001). In the majority of the benign and malignant nodules there was no change in morphology, shape and margin during 1 year of follow-up (p = ns).

Conclusion

Baseline nodule density and changes in nodule features cannot be used to discriminate between benign and malignant solid indeterminate pulmonary nodules, but an increase in density is suggestive for malignancy and requires a shorter follow-up or a biopsy.     

Vascular patterns in nodules of intraductal papillary mucinous neoplasms depicted under contrast-enhanced ultrasonography are helpful for evaluating malignant potential

Objectives

The purpose of this study is to evaluate the feasibility of contrast-enhanced ultrasonography (CE-US) to differentiate between benign and malignant intraductal papillary mucinous neoplasms (IPMN).

Patients and methods

Contrast-enhanced ultrasonography with a contrast agent was performed on 22 consecutive patients with IPMN suspected of being malignant. This revealed 10 carcinomas, 1 borderline lesion and 11 adenomas. All patients underwent surgery, and the histological diagnosis was confirmed by examination of resected specimens. CE-US was performed using a contrast agent. The detection rates of mural nodules were compared between CE-US and contrast-enhanced computed tomography (CE-CT), and the imaging of mural nodules depicted under CE-US was analyzed.

Results

Seventeen of 22 resected specimens (77.3%) had mural nodules. There was no significant difference in the detection rate between CE-US (n = 15; 88.2%) and CE-CT (n = 12; 70.6%). In 12 (80.0%) of these patients, CE-US revealed small vessels in the mural nodule. The spotty or linear-shaped pattern was detected in 4 patients and the branch-shaped pattern in 8. The branch-shaped pattern lesion was associated with carcinoma. These mural nodules were 10 mm or more in height. In the perfusion image phase, cystic walls and mural nodules were also enhanced in all cases.

Conclusion

The vessel shapes of the mural nodules depicted under CE-US were associated with size and pathological findings. These results suggested that CE-US with a contrast agent is a powerful modality with which to evaluate the malignant potential of IPMN.     

The effect of nuchal cord on nuchal fold thickness measured in the second trimester

Purpose

To find out whether nuchal cord causes an effect on the nuchal skin fold thickness (NFT) measurements, or not.

Patients and methods

A total of 242 fetuses with normal outcomes that had undergone detailed second trimester US scan between 18 and 24 weeks of gestation were included in the study. NFT measurements were made on axial cranial US images passing through the cerebellum and cavum septi pellucidum. To detect nuchal cord, color Doppler imaging was performed on the axial views of the fetal neck. To investigate the differences in NFT measurements of the fetuses with or without nuchal cord, statistical analysis was performed using Mann–Whitney test. P < 0.05 was considered statistically significant.

Results

The study group was divided into two groups: nuchal cord (+) (n: 26) and nuchal cord (−) (n: 216) fetuses. Mean NFT measurements were 4.66 ± 0.64 mm and 4.36 ± 0.79 mm for nuchal cord (+) and nuchal cord (−) fetuses, respectively. Median NFT measurement for nuchal cord (+) fetuses was 4.6 mm, whereas it was 4.4 mm for nuchal cord (−) fetuses. Statistically significant difference was denoted between two groups, in terms of NFT measurements (P = 0.049).

Conclusion

NFT measurements of fetuses with nuchal cord are higher than the NFT measurements of fetuses without nuchal cord. One can conclude that the nuchal cord (+) fetuses with no other anomalies but increased NFT should be re-scanned to see if the increased NFT resolves in the absence of nuchal cord.     

Hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase of gadoxetic acid-enhanced MRI in patients with chronic liver disease: prediction of malignant transformation

Purpose

To investigate the predictive factors of malignant transformation of hypovascular hepatic nodule showing hypointensity in the hepatobiliary phase images of gadoxetic acid-enhanced MRI (HHN).

Materials and Methods

The clinical data and imaging findings of dynamic contrast-enhanced computed tomography (DCE-CT) and gadoxetic acid-enhanced MRI for a total of 103 HHNs in 24 patients with chronic liver disease were retrospectively investigated. After the results of follow-up examinations were investigated, HHNs were categorized into the three groups for each comparison: (1) nodules with enlargement and/or vascularization and others, (2) nodules with only enlargement and others, (3) nodules with only vascularization and others. Enlargement and/or vascularization during the follow-up period were defined as malignant transformation of HHN. The frequency of each clinical datum and imaging finding in each group was compared to identify the predictive factors for malignant transformation in HHN.

Results

Multivariate analysis showed that a nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI was a significant predictive factor for the enlargement and/or vascularization of HHN (P < 0.05). On the other hand, the hypoattenuation on the delayed phase imaging of the initial DCE-CT was a significant predictive factor for the enlargement or vascularization of HHN (P < 0.05).

Conclusion

A nodule size of 9 mm or more on the initial gadoxetic acid-enhanced MRI and hypoattenuation on the delayed phase imaging of initial DCE-CT would be helpful for predicting the outcome of HHN in patients with a risk of hepatocellular carcinoma.     

Evaluation of tumor extent in breast cancer patients using real-time MR navigated ultrasound: Preliminary study

Objectives

To evaluate the accuracy of real-time MR navigated ultrasound (MRnav US) for tumor extent measurements in breast cancer and to investigate variables influencing the accuracy of MRnav US in comparison with US alone.

Methods

Fifty-three patients with 60 malignancies underwent preoperative breast MRI and US with or without MRI navigation. Maximum lesion sizes based on MRnav US and US alone were measured, and their relationship with the pathology was analyzed considering the differences in the clinicopathologic variables of the patients.

Results

Among 60 breast cancers, mean lesion size at initial breast US without MRI navigation and at MRI-navigated US was 19 mm and 24 mm, respectively, compared with 28 mm on the histopathology. Overall, the tumor size estimated with MRnav US was more strongly correlated with the histologic tumor size than with US alone. Accurate measurements by MRnav US were significantly more frequent in the lesions that were presented as a mass type on MRI. In addition, the accurate measurement of mass extent was improved with MRnav US in patients who had non-mass type lesions on MRI and who had undergone neoadjuvant systemic chemotherapy when compared with US alone.

Conclusion

MRnav US was more accurate for tumor extent estimation than US alone, and specific clinicopathologic variables can affect the accuracy of MRnav US.     

Prospective evaluation of multiparametric ultrasound and quantitative elastosonography in the differential diagnosis of benign and malignant thyroid nodules: preliminary experience

Purpose

To assess the clinical value of quantitative elastosonography compared with multiparametric ultrasound in differentiating the nature of thyroid nodules.

Methods and materials

Ninety-seven consecutive patients (32 males, 65 females, mean age, 54 years, range 20–81 years) with thyroid nodules previously detected at color-Doppler ultrasound (CDUS), were prospectively examined with elastosonography with dedicated quantitative software (Elasto-Q, Toshiba) before surgery. Ultrasound examination and elastosonography were evaluated by two investigators in consensus. US features, color-Doppler pattern, and strain ratio value were evaluated. Sensitivity and specificity of CDUS and sono-elastography were compared using X² test and ROC curves.

Results

Sensitivity and specificity of hypoechogenicity, irregular margins or suspicious halo features, CDUS blood flow pattern, and strain ratio in the diagnosis of malignant nodules were 56.8%, 62.2%, 54.1% and 97.3% and 71.7%, 93.3%, 28.3%, and 91.7%, respectively. Elastosonography was more sensitive and specific than all ultrasonographic features in predicting malignancy of the thyroid nodules (p < 0.0001). According to elastosonographic features the lesions characterized by strain ratio ≥2 were highly likely to be of malignant nature (p < 0.0001, O.R. 396, 95%, CI: 44–3530).

Conclusions

The results of the present study suggest that elastosonography with Q system is a valuable tool in the characterization of thyroid nodules and it seems to be far more accurate than CDUS. These findings as well as those of previous studies support its use in selecting patients who are candidates for surgery.     

CT patterns of fungal pulmonary infections of the lung: comparison of standard-dose and simulated low-dose CT

Purpose

To assess the effect of radiation dose reduction on the appearance and visual quantification of specific CT patterns of fungal infection in immuno-compromised patients.

Materials and methods

Raw data of thoracic CT scans (64 × 0.75 mm, 120 kVp, 300 reference mAs) from 41 consecutive patients with clinical suspicion of pulmonary fungal infection were collected. In 32 patients fungal infection could be proven (median age of 55.5 years, range 35–83). A total of 267 cuboids showing CT patterns of fungal infection and 27 cubes having no disease were reconstructed at the original and 6 simulated tube currents of 100, 40, 30, 20, 10, and 5 reference mAs. Eight specific fungal CT patterns were analyzed by three radiologists: 76 ground glass opacities, 42 ground glass nodules, 51 mixed, part solid, part ground glass nodules, 36 solid nodules, 5 lobulated nodules, 6 spiculated nodules, 14 cavitary nodules, and 37 foci of air-space disease. The standard of reference was a consensus subjective interpretation by experts whom were not readers in the study.

Results

The mean sensitivity and standard deviation for detecting pathological cuboids/disease using standard dose CT was 0.91 ± 0.07. Decreasing dose did not affect sensitivity significantly until the lowest dose level of 5 mAs (0.87 ± 0.10, p = 0.012). Nodular pattern discrimination was impaired below the dose level of 30 reference mAs: specificity for fungal ‘mixed nodules’ decreased significantly at 20, 10 and 5 reference mAs (p < 0.05). At lower dose levels, classification drifted from ‘solid’ to ‘mixed nodule’, although no lesion was missed.

Conclusion

Our simulation data suggest that tube current levels can be reduced from 300 to 30 reference mAs without impairing the diagnostic information of specific CT patterns of pulmonary fungal infections.     

The role of second-look ultrasound of BIRADS-3 mammary lesions detected by breast MR imaging

Objective

To asses the value of second-look ultrasound (US) for identifying BIRADS 3 (Breast Imaging Reporting Data System) mammary lesions detected by breast Magnetic Resonance imaging (MRI).

Materials and methods

From April 2008 to May 2009 330 breast MRI were performed of which 60 patients are classified as BIRADS 3. 84 lesions underwent second-look US and percutaneous vacuum biopsy Vacora system US-guided. Statistical analysis: lesions were stratified into two groups: visible on US (Group 1) and not visible on US (Group 2).The clinical impact of second-look US was studied in terms of negative predictive value (NPV).

Results

The positive predictive value (PPV) of category 3 BIRADS MRI was found to be 89%. Second look-US results detected lesions in 51% of the MRI enhancing lesions. The second look-US showed a NPV of 97%. The NPV of second look-US was significantly greater than the NPV of MRI BIRADS 3 (97% vs 89%, p < 0.05). The logistic regression analysis showed a higher number of malignant lesions in group 1 than in group 2 (7vs 2, OR 3.7, p < 0.05).

Conclusions

The second-look US permitted the correct management of subcentimetric MRI BIRADS 3 lesions not visible with conventional imaging tecniques.     

Potential contribution of multiplanar reconstruction (MPR) to computer-aided detection of lung nodules on MDCT

Purpose

To evaluate potential benefits of using multiplanar reconstruction (MPR) in computer-aided detection (CAD) of lung nodules on multidetector computed tomography (MDCT).

Materials and methods

MDCT datasets of 60 patients with suspected lung nodules were retrospectively collected. Using “second-read” CAD, two radiologists (Readers 1 and 2) independently interpreted these datasets for the detection of non-calcified nodules (≥4 mm) with concomitant confidence rating. They did this task twice, first without MPR (using only axial images), and then 4 weeks later with MPR (using also coronal and sagittal MPR images), where the total reading time per dataset, including the time taken to assess the detection results of CAD software (CAD assessment time), was recorded. The total reading time and CAD assessment time without MPR and those with MPR were statistically compared for each reader. The radiologists’ performance for detecting nodules without MPR and the performance with MPR were compared using jackknife free-response receiver operating characteristic (JAFROC) analysis.

Results

Compared to the CAD assessment time without MPR (mean, 69 s and 57 s for Readers 1 and 2), the CAD assessment time with MPR (mean, 46 s and 45 s for Readers 1 and 2) was significantly reduced (P < 0.001). For Reader 1, the total reading time was also significantly shorter in the case with MPR. There was no significant difference between the detection performances without MPR and with MPR.

Conclusion

The use of MPR has the potential to improve the workflow in CAD of lung nodules on MDCT.     

Pancreatic neuroendocrine tumor: added value of fusion of T2-weighted imaging and high b-value diffusion-weighted imaging for tumor detection

Objectives

To investigate the added value of fusion of high b-value diffusion-weighted images (DWI) and T2-weighted (T2) MR images for the detection of pancreatic neuroendocrine tumors (PNT).

Methods

18 patients with 18 histologically proven PNT were included. Two radiologists independently and retrospectively reviewed four randomized images sets (T2+T1, DWI, T2+DWI, and DWI+T2 fusion). Lesion detection confidence level was assessed using a three grade score (no lesion; uncertain lesion and certain lesion); lesion size and signal intensity were recorded. Apparent diffusion coefficients (ADC) of tumor and adjacent pancreas were measured.

Results

Readers 1 and 2 respectively detected 14/18 and 16/18 lesions on T2+T1, 13/18 and 12/18 on DWI, 16/18 and 15/18 on T2+DWI and 17/18 and 16/18 on DWI+T2 fusion. Lesion median size was 16 mm (range: 7 mm–40 mm), 22% were hyperfunctioning (all insulinomas) and 72% were low-grade (Rindi 1). All tumors except one (with cystic component) showed lower ADC than adjacent pancreatic parenchyma. Fusion imaging had significantly better detection score by both authors (p < 0.005) and provided the higher inter-reader agreement (kappa 0.7). DWI alone had the worst score for both readers.

Conclusions

Fusion images improve the detection of PNT, especially in patients with small isointense lesions on conventional MR sequences.     

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.     

High spatial resolution MRA of renal arteries using contrast behavior between fat and water during transient phase before reaching a steady state

Purpose

Our aim is high spatial resolution imaging of maximum intensity projection (MIP) images in renal magnetic resonance angiography (MRA) by constructing a protocol for acquiring three-dimensional volume data with isotropic voxels.

Materials and methods

We eliminated water-selective excitation (WATS) and utilized effective contrast behavior between fat and water before reaching a steady state—that is, during the transient phase—to cover fat suppression by WATS. In a phantom study, the optimal flip angle was investigated under the “low-high Y” profile order using distilled water and baby oil to construct a protocol with isotropic voxels. Signal intensity, contrast, noise and signal-to-noise ratio were investigated to compare image qualities between the conventional and the constructed isotropic protocols. In a clinical study, three radiologists and two radiological technologists visually evaluated clinical images of 20 volunteers for spatial resolution, contrast and overall reader confidence in two protocols.

Results

We constructed an isotropic protocol with voxel dimensions of 0.78 mm × 0.78 mm × 0.78 mm at a flip angle of 90°. We maintained the scan time but enlarged the x–y pixel dimensions from 0.59 mm × 0.59 mm to 0.78 mm × 0.78 mm and shortened image height from 48 mm to 42.9 mm. Data from the phantom study were worse in the isotropic protocol than in the conventional protocol. However, overall reader confidence in the clinical images was significantly better in the isotropic protocol than in the conventional protocol (p < .001).

Conclusion

Our study indicated the value of addressing high spatial resolution imaging of MIP images for renal MRA by constructing an isotropic protocol.     

Contribution of thin slice (1 mm) oblique coronal proton density-weighted MR images for assessment of anteromedial and posterolateral bundle damage in anterior cruciate ligament injuries

Purpose

To evaluate the diagnostic efficacy of using additional oblique coronal 1 mm proton density-weighted (PDW) MR imaging of the knee for detection and grading anterior cruciate ligament (ACL), anteromedial bundle (AMB) and posterolateral bundle (PLB) injuries.

Materials and methods

We prospectively assessed preoperative MR images of 50 patients (36 men, 14 women; age range, 18–62 years). First, we compared the diagnostic performance of routine sagittal (3 mm) and additional oblique coronal images (1 mm) for ACL tears. Then, we compared the tear types (AMB or PLB) and grade presumed from oblique coronal MR imaging with arthroscopy.

Results

Arthroscopy revealed ACL tear in 24 (48%) patients. There was significant difference between sagittal images and arthroscopy results for ACL tear recognition (p < 0.001). No significant difference was detected for oblique coronal images when compared with arthroscopy results (p = 0.180). Sensitivity and specificity values for ACL tear diagnosis were 37.04% and 95.65% for sagittal images; 74.07% and 91.30% for oblique coronal images. There was no significant difference between arthroscopy and oblique coronal MR images in grading AMB and PLB injuries (p > 0.05).

Conclusion

Addition of thin slice oblique coronal images to conventional sequences could better contribute to better verifying the presence of ACL tear and in determining its grade.     

Fusion of multislice computed tomography and electroanatomical mapping data for 3D navigation of left and right atrial catheter ablation

Purpose

To assess whether fusion of multislice computed tomography (CT) images with electroanatomical (EA)-mapping data using a new image integration module (CartoMerge™) is feasible and accurate to navigate ablation catheters in right and left atrial catheter ablation.

Material and methods

Twenty-four patients were examined with ECG-gated cardiac multislice CT (64 mm × 0.6 mm, 0.33 s) 1 day before left atrial (LA) (15 patients) radiofrequency or right atrial cavotricuspid isthmus ablation (9 patients). CT data were fused with the non-fluoroscopic EA-mapping data by using dedicated software (CartoMerge™) and the value of CT was analysed.

Results

In 23/24 (96%) patients, CT images could be fused with the EA-map. The alignment error was 2.16 ± 0.35 mm. In 15/15 (100%) patients, CT added relevant anatomical information regarding the course of the esophagus or the pulmonary veins before LA-ablation. CT added useful information in only 3/8 (37.5%) of patients undergoing right atrial cavotricuspid isthmus ablation.

Conclusion

3D-navigation of RF-ablation catheters in the atria assisted by image fusion of multislice CT with EA-mapping data is feasible and accurate. CT added relevant anatomical information about the left atrium and the pulmonary veins before LA-ablation, CT also provided information about the course of the esophagus which might help to avoid thermal injury. CT image fusion might be of minor value before right atrial cavotricuspid isthmus catheter ablation.     

Sinonasal imaging after Caldwell-Luc surgery: MDCT findings of an abandoned procedure in times of functional endoscopic sinus surgery

Background and purpose

Today, functional endoscopic sinus surgery (FESS) is performed in most of the patients with sinonasal inflammatory disease. The postoperative imaging findings of FESS in multidetector computed tomography (MDCT) considerably differ from those of historic Caldwell–Luc (CL) maxillary sinus surgery which is an uncommon procedure today. Thus, the postoperative CL imaging findings may lead to diagnostic confusion and misinterpretation. Therefore, this study explicitly presents the MDCT findings of post-CL patients which have not been described previously.

Methods

Twenty-eight patients with clinically suspected sinusitis and documented history of CL-procedure underwent 16 row MDCT (MDCT Mx8000 IDT Philips) with multiplanar reconstructions of the paranasal sinuses in the axial plane. The following parameters were used: 140 kV, 50 mAs; 16 mm × 0.75 mm detector collimation; 1 mm reconstructed slice thickness; 0.5 mm increment. The studies were reconstructed with a bone algorithm (W3000/L600; 1 mm slice thickness) in axial plane and coronal plane (3 mm slice thickness). The images were retrospectively evaluated for the presence of normal surgery-related and pathological findings.

Results

Surgery-related imaging characteristics presented as follows: an anterior and a medial bony wall defect and sclerosis and sinus wall thickening were observed in all 28/28 cases (100%). Collaps of the sinus cavity was seen in 26/28 cases (92.9%). Furthermore, inflammatory disease of the operated sinus(es) was found in 23/28 cases (82.1%): 14/28 patients (50%) had inflammatory mucosal thickening of the operated sinus(es) as well as of other sinonasal cavities and 9/28 patients (32.1%) had inflammatory mucosal thickening limited to the operated sinus(es). A postoperative mucocele was depicted in 3/28 cases (10.7%). 2/28 patients (7.1%) showed neither maxillary nor other mucosal swelling.

Conclusion

MDCT with multiplanar reconstructions is a precise method to evaluate post-CL patients and helps to differentiate normal surgery-related findings, which may mimic pathology, from real pathological findings.     

The value of strain ratio in differential diagnosis of thyroid solid nodules

Objective

To assess the clinical value of strain ratio in differentiating thyroid solid nodules and explore its distribution characters based on pathological results.

Materials and methods

The study was approved by the ethic committee and the informed consents were signed. Ninety nine solid thyroid nodules (67 benign and 32 malignant) from 71 female (mean age 46.3 ± 9.8 years) and 28 male (mean age 54.9 ± 11.7 years) patients were evaluated. Five radiologists evaluated the nodules based on a four-degree elastography score system. Strain ratio was calculated on-line. Diagnostic performances of the two evaluations were compared using Receiver Operating Characteristic (ROC) curves. Values of different pathological nodules were compared by one-way ANOVA.

Results

Areas under the ROC curve (AUC) of the five readers were 0.82, 0.81, 0.79, 0.73 and 0.83, respectively. The AUC of strain ratio evaluation was higher (0.88 vs. 0.79, p < 0.001) than that of the ES score evaluation. Best cut-off points of the two evaluations were 3.5 (82% sensitivity, 72% specificity) and 4.225 (81% sensitivity, 83% specificity), respectively. Both the ES score and strain ratio were higher for malignant nodules than that for benign ones (p < 0.001).

Conclusions

Strain ratio was a useful index in differential diagnosis of thyroid solid nodules. It can provide quantitative information on thyroid nodule characterization and improve diagnostic confidence. The best cut-off point for benign and malignant nodules was 4.2.     

MR determination of neonatal spinal canal depth

Objectives

Lumbar punctures (LPs) are frequently performed in neonates and often result in traumatic haemorrhagic taps. Knowledge of the distance from the skin to the middle of the spinal canal (mid-spinal canal depth – MSCD) may reduce the incidence of traumatic taps, but there is little data in extremely premature or low birth weight neonates. Here, we determined the spinal canal depth at post-mortem in perinatal deaths using magnetic resonance imaging (MRI).

Patients and methods

Spinal canal depth was measured in 78 post-mortem foetuses and perinatal cases (mean gestation 26 weeks; mean weight 1.04 kg) at the L3/L4 inter-vertebral space at post-mortem MRI. Both anterior (ASCD) and posterior (PSCD) spinal canal depth were measured; MSCD was calculated and modelled against weight and gestational age.

Results

ASCD and PSCD (mm) correlated significantly with weight and gestational age (all r > 0.8). A simple linear model MSCD (mm) = 3 × Weight (kg) + 5 was the best fit, identifying an SCD value within the correct range for 87.2% (68/78) (95% CI (78.0, 92.9%)) cases. Gestational age did not add significantly to the predictive value of the model.

Conclusion

There is a significant correlation between MSCD and body weight at post-mortem MRI in foetuses and perinatal deaths. If this association holds in preterm neonates, use of the formula MSCD (mm) = 3 × Weight (kg) + 5 could result in fewer traumatic LPs in this population.