Reproducibility of CT texture features of pancreatic neuroendocrine neoplasms

PURPOSE

To evaluate the reproducibility of textural features of pancreatic neuroendocrine neoplasms (PNENs), obtained under various CT-scanning conditions.

METHODS AND MATERIALS

We included 12 patients with PNENs and 2 contrast enhanced CT (CECT): 1) from our center according to standard CT-protocol; 2) from another institution. Two radiologists independently segmented the entire neoplasm volume using a 3D region of interest by LIFEx application on the arterial phase and then copied it to the other phases. 52 texture features were calculated for each phase. As a criterion for the segmentation consistency, a value of neoplasm volume was compared using the Bland-Altman method. The Kendall concordance coefficient was calculated to assess the texture features reproducibility in three scenarios: 1) different radiologists, same CECT; 2) same radiologist, different CECT; 3) different radiologists, different CECT.

RESULTS

For the scenario 1 the neoplasm volumes (except one large PNEN) were found within two standard deviations; this indicates high consistency of the segmentation. For the first scenario, Kendall's coefficient exceeded a threshold of 0.7 for all 52 features for all CT phases. For the second and third scenario, the concordance coefficient exceeded a threshold of 0.7 in 38, 28, 42, 45 and in 36, 25, 36, 44 features for the native, arterial, venous and delayed phases, respectively.

CONCLUSION

The highest reproducibility was found in the first scenario compared to the second and third: 100 % vs. 74 % and 67 %. Reproducible texture features can be reliably used to assess the PNENs structure.

Low radiation dose 256-MDCT angiography of the carotid arteries: effect of hybrid iterative reconstruction technique on noise, artifacts, and image quality

To evaluate the effect of hybrid iterative reconstruction on qualitative and quantitative parameters at low dose carotid CTA.

MATERIALS AND METHODS

44 consecutive patients were enrolled in the study. First group (n=22) was examined under 120 kV 250 mAs, second group (n = 22) - 100 kV 250 mAs. CT images in first group were reconstructed only with the filtered back projection (FBP). CT data in second group were reconstructed both with FBP and three levels of hybrid iterative reconstruction algorithm (iDose). We compared quantitative and qualitative parameters among the two groups and among four different reconstructions in second group.

RESULTS

Effective dose in 120 kV and 100 kV group was 7.18 ± 1.19 mSv and 4.14 ± 1.03 mSv, respectively (p<0.0001). Mean arterial attenuation was about 25% higher in second group (236.5 ± 46 HU vs. 302.6 ± 32.7 HU; p<0.0001). Image noise at the level of humeral belt was 32.5 ± 12.5 in 100 kV group and 26.3 ± 13.3 in 120 kV (p = 0.115). Average noise decreased when using 3 levels of iDose up to 23.6 ± 6.4, 17.7 ± 5.6 and 13.7 ± 5.1, respectively (p = 0.00001). Mean CNR increased to 10.38 ± 3.87, 14.5 ± 5.21 and 18.32 ± 8.61, respectively (p<0.05). The presence of artifacts on the level of humeral belt in 120 kV group was 14%, in 100 kV - 41% (p = 0.002). The difference in visual scores between standard and low-dose protocol was significant (p = 0.008). When applying iterative reconstruction the frequency of streak artifacts decreased dramatically (p<0.0001). Most studies had excellent quality with no artifacts while using highest level of iDose.

CONCLUSION

According to the results of our study low dose CT angiography using hybrid iterative reconstruction may provide sufficient image quality and allows for significant reduction of patient dose.

Metastasis of endometrial cancer to right hemidiaphragm: A case report

INTRODUCTION

Tumors of the diaphragm are uncommon. The overwhelming number of cases is metastatic combined with metastases to the liver, lungs and other organs. Only a minority of cases are described as solitary lesions.

CASE PRESENTATION

Fifty-five years old female with a history of radical curative surgery for pT3N0M0 endometrial cancer eight years ago was admitted to the Department of Thoracic Surgery with a feeling of discomfort in the right hypochondrium. The contrast-enhanced MDCT revealed a large, well-circumscribed lesion of the right hemidiaphragm deforming upper contour of the liver. A clear boundary between the lesion and the liver suggested former's diaphragmatic origin. PET-CT did not show any distant metastasis. Intraoperative revision revealed a tumor growing from the dome of the diaphragm with well-defined contours and without any signs of lung involvement. The diaphragmotomy was performed. The morphological study with immunohistochemistry showed an endometrial carcinoma metastasis to the diaphragm.

CONCLUSION

The diaphragm lesions can have various etiology, but a probability of tumor metastasis after a previous radical surgery should not be excluded. Preoperative differential diagnostics can be difficult, leaving surgical treatment followed by a pathology study as the most informative diagnostic method of tumor morphology.

Virtual modeling of robot-assisted manipulations in abdominal surgery

AIM

To determine the effectiveness of using multidetector computed tomography (MDCT) data in preoperative planning of robot-assisted surgery.

METHODS

Fourteen patients indicated for surgery underwent MDCT using 64 and 256-slice MDCT. Before the examination, a specially constructed navigation net was placed on the patient's anterior abdominal wall. Processing of MDCT data was performed on a Brilliance Workspace 4 (Philips). Virtual vectors that imitate robotic and assistant ports were placed on the anterior abdominal wall of the 3D model of the patient, considering the individual anatomy of the patient and the technical capabilities of robotic arms. Sites for location of the ports were directed by projection on the roentgen-positive tags of the navigation net.

RESULTS

There were no complications observed during surgery or in the post-operative period. We were able to reduce robotic arm interference during surgery. The surgical area was optimal for robotic and assistant manipulators without any need for reinstallation of the trocars.

CONCLUSION

This method allows modeling of the main steps in robot-assisted intervention, optimizing operation of the manipulator and lowering the risk of injuries to internal organs.