Influence of splenomegaly on aortic and liver parenchymal CT numbers during contrast-enhance CT in patients with cirrhosis

INTRODUCTION

To compare CT (computed tomography) values for enhancement of the abdominal aorta and liver parenchyma during dynamic contrast enhancement (CE) CT in cirrhotic patients with and without splenomegaly (SM).

METHODS

We considered 258 patients (83 males and 46 females for the splenomegaly group, and 83 males and 46 females for the control group) for this retrospective study. We measured CT values in the abdominal aorta and hepatic parenchyma during the hepatic arterial (HAP) and portal venous (PVP) phases. The aortic CE at HAP and the hepatic parenchymal CE at PVP were compared between the two groups. For success rate of scans, we also calculated the optimal CE rates (>280 HU in the abdominal aorta and >50 HU in the hepatic parenchyma) for each group.

RESULTS

In the SM group, the CE for abdominal aorta was decreased during the aortic phase for a dynamic CE-CT (p < 0.05). When evaluating the success rates, they were found to be 65.1 % and 58.9 % in the SM group and 81.4 % and 72.3 % in the non-SM group (p < 0.05).

CONCLUSION

The success rate of scans and CE for the abdominal aorta during the aortic phase exhibited a significant decrease during dynamic CE-CT scans on patients with SM. Patients with SM may have reduced diagnostic ability with typical contrast injection protocols.

IMPLICATIONS FOR PRACTICE

It may be necessary to change the injection rates and contrast medium volume during CE-CT depending on the presence or absence of SM.

A novel approach using volumetric dynamic airway computed tomography to determine positive end-expiratory pressure (PEEP) settings to maintain airway patency in ventilated infants with bronchopulmonary dysplasia

BACKGROUND

Positive end-expiratory pressure (PEEP) is a key mechanical ventilator setting in infants with bronchopulmonary dysplasia (BPD). Excessive PEEP can result in insufficient carbon dioxide elimination and lung damage, while insufficient PEEP can result in impaired gas exchange secondary to airway and alveolar collapse. Determining PEEP settings based on clinical parameters alone is challenging and variable.

OBJECTIVE

The purpose of this study was to describe our experience using dynamic airway CT to determine the lowest PEEP setting sufficient to maintain expiratory central airway patency of at least 50% of the inspiratory cross-sectional area in children with BPD requiring long-term ventilator support.

MATERIALS AND METHODS

We retrospectively identified all infants with BPD who underwent volumetric CT with a dynamic airway protocol for PEEP optimization from December 2014 through April 2019. Sixteen infants with BPD underwent 17 CT exams. Each CT exam consisted of acquisitions spanning the trachea and mainstem bronchi. We measured cross-sectional area of the trachea and mainstem bronchi and qualitatively assessed the amount of atelectasis. We documented changes in management as a result of the CT exam.

RESULTS

The average effective dose was 0.1-0.8 mSv/scan. Of 17 CT exams, PEEP was increased in 9, decreased in 3 and unchanged after 5 exams.

CONCLUSION

Dynamic airway CT shows promise to assist the clinician in determining PEEP settings to maintain airway patency in infants with BPD requiring long-term ventilator support. Further evaluation of the impact of this maneuver on gas exchange, cardiac output and other physiological measures is needed.

Preoperative Assessment of Pathologic Subtypes of Meningioma and Solitary Fibrous Tumor/Hemangiopericytoma Using Dynamic Computed Tomography: A Clinical Research Study

BACKGROUND

Solitary fibrous tumors (SFTs)/hemangiopericytomas (HPCs) are highly vascularized tumors well known for malignant, invasive, and highly vascular features. To date, several studies have reported the preoperative imaging findings of SFTs/HPCs. In this study, computed tomography (CT) tumor values acquired from dynamic CT scan were selected to determine the tumor pathology of highly vascular tumors, such as SFTs/HPCs.

METHODS

We conducted a retrospective study on patients with pathologically diagnosed meningiomas and SFTs/HPCs who had undergone a dynamic contrast CT scan. We assessed and compared the CT values of these tumors according to the pathology.

RESULTS

From a total of 34 patients, 30 patients with meningiomas and 4 patients with HPCs were included. The mean CT values of SFTs/HPCs and angiomatous meningioma were statistically significantly higher than those of the other meningioma subtypes (P = 0.003). We also performed receiver operating characteristic curve analyses to detect an appropriate cutoff point for the CT value to differentiate tumor pathology, and the calculated threshold was 161 Hounsfield units (HU) (sensitivity, 100%; specificity, 75%; area under the curve, 0.87; 95%, CI 0.75-0.99).

CONCLUSIONS

This study showed that obtaining a CT value is useful in determining highly vascular tumor pathology preoperatively. When considering neurosurgical extra-axial tumor removal, and when the CT value of tumors is >161 HU, then highly vascular tumors such as SFTs/HPCs or angiomatous meningiomas are likely, and this should be considered prior to surgical intervention and for risk assessment.

Detection of inspiratory recruitment of atelectasis by automated lung sound analysis as compared to four-dimensional computed tomography in a porcine lung injury model

Background

Cyclic recruitment and de-recruitment of atelectasis (c-R/D) is a contributor to ventilator-induced lung injury (VILI). Bedside detection of this dynamic process could improve ventilator management. This study investigated the potential of automated lung sound analysis to detect c-R/D as compared to four-dimensional computed tomography (4DCT).

Methods

In ten piglets (25 ± 2 kg), acoustic measurements from 34 thoracic piezoelectric sensors (Meditron ASA, Norway) were performed, time synchronized to 4DCT scans, at positive end-expiratory pressures of 0, 5, 10, and 15 cmH₂O during mechanical ventilation, before and after induction of c-R/D by surfactant washout. 4DCT was post-processed for within-breath variation in atelectatic volume (Δ atelectasis) as a measure of c-R/D. Sound waveforms were evaluated for: 1) dynamic crackle energy (dCE): filtered crackle sounds (600–700 Hz); 2) fast Fourier transform area (FFT area): spectral content above 500 Hz in frequency and above −70 dB in amplitude in proportion to the total amount of sound above −70 dB amplitude; and 3) dynamic spectral coherence (dSC): variation in acoustical homogeneity over time. Parameters were analyzed for global, nondependent, central, and dependent lung areas.

Results

In healthy lungs, negligible values of Δ atelectasis, dCE, and FFT area occurred. In lavage lung injury, the novel dCE parameter showed the best correlation to Δ atelectasis in dependent lung areas (R² = 0.88) where c-R/D took place. dCE was superior to FFT area analysis for each lung region examined. The analysis of dSC could predict the lung regions where c-R/D originated.

Conclusions

c-R/D is associated with the occurrence of fine crackle sounds as demonstrated by dCE analysis. Standardized computer-assisted analysis of dCE and dSC seems to be a promising method for depicting c-R/D.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-1964-6) contains supplementary material, which is available to authorized users.

Dynamic computed tomography of the pituitary gland using a single slice scanner in dogs with pituitary-dependent hypercortisolism

Selective removal of the pituitary adenoma has not been advocated in dogs with pituitary-dependent hypercortisolism because the pituitary adenoma is usually not visualized on routine computed tomography (CT). Dynamic pituitary CT scanning is aimed at the detection of the pituitary flush and, indirectly, at the presence and position of the adenoma. The first aim of this retrospective study was to compare findings of a multiple slice dynamic scanning protocol with those of a single slice dynamic protocol using a single slice CT scanner. The second aim was to compare the CT findings with surgical findings, and surgical findings with histopathological findings. Computed tomography with single and multiple slice dynamic scanning protocols was performed in 86 dogs with pituitary-dependent hypercortisolism. Thirty dogs underwent transsphenoidal hypophysectomy and pituitary specimens were collected as tumor, normal, mixed and neurohypophyseal samples and processed for histology. The pituitary flush was not detected more frequent in multiple slice dynamic scanning series than in single slice dynamic scanning series. However, in non-enlarged pituitaries, the flush was seen significantly more frequently than in enlarged pituitaries. Prediction of the nature of the tissue during hypophysectomy by the surgeon was inconclusive. In conclusion, when using a single slice CT scanner, both single or multiple slice dynamic scanning protocols can be used for localization of the neurohypophyseal flush, and, indirectly, the adenoma. However, based on this study, the aim of surgery in dogs with pituitary-dependent hypercortisolism remains total adenohypophysectomy, and when the neurophypophysis is recognized, it may be left in situ.

Hepatocellular adenoma: comparison between real-time contrast-enhanced ultrasound and dynamic computed tomography

Purpose

To investigate and compare the contrast-enhanced ultrasound (CEUS) features of histologically proven HCA with those of contrast-enhanced computed tomography (CECT).

Methods

Eighteen patients with proven hepatic adenoma by pathology were retrospectively selected from the CEUS database. Fourteen of them had undergone liver CECT exams. The basic features on unenhanced imaging and the enhancement level and specific features on contrast-enhanced imaging were retrospectively analyzed, and the differences between CEUS and CECT were compared.

Results

All the HCAs showed hyper-enhancement in the arterial phase. During the portal and late phases, 12 HCAs (12/18, 66.7 %) on CEUS and 11 (11/14, 78.6 %) on CT showed washout. On CEUS, 10 (10/18, 55.5 %) showed centripetal filling in the arterial phase and persistent peripheral rim enhancement. Five of them (61.1 %, 11/18) showed delayed central washout in the portal or late phase. However, on CECT, 2 (14.3 %, 2/14) and 4 (28.6 %, 4/14) HCAs showed persistent enhancement of the peripheral rim and central non-enhancing hemorrhage areas, respectively.

Conclusions

Compared with dynamic CT, CEUS was superior at characterizing specific dynamic features. Considering that it is radiation-free, readily availability and easy to use, CEUS is suggested as the first line imaging tool to diagnose HCA.

Dynamic computed tomography findings of an accessory spleen in the pelvis: a case report

We report the case of a 60-year-old man with an accessory spleen in the pelvis. He visited our outpatient clinic because of abdominal discomfort. Computed tomography (CT) showed an enhanced mass (40 mm in diameter) in the pelvis. Preoperative diagnosis was difficult even after magnetic resonance imaging and colonoscopy. The patient underwent surgery for suspicion of a gastrointestinal stromal tumor or malignant lymphoma of the rectum. Intraoperative findings showed a mass in the pelvis and a long cord-like tissue reaching the mass and arising from the great omentum; the mass was excised. Histopathologic examination indicated that the mass was splenic tissue, and feeding vessels were found in the cord-like tissue, which were determined to be derived from the left gastroepiploic artery and vein. Thus, we diagnosed it as an accessory spleen in the pelvis. An accessory spleen is not rare and can occur anywhere in the abdominal cavity. However, an accessory spleen in the pelvis is an infrequent finding, and only 9 other cases of an accessory spleen in the pelvis have been reported. Therefore, it is very difficult to make a correct diagnosis preoperatively. However, 7 of the 9 cases (77.8 %) of a pelvic accessory spleen had vascular pedicles from the great omentum or splenic hilum as feeding vessels; hence, determining the feeding blood vessels on dynamic CT may be useful for diagnosing an accessory spleen in the pelvis. Additionally, if the accessory spleen is symptomatic or has a vascular pedicle, surgeons should attempt to resect the accessory spleen in the pelvis using minimally invasive laparoscopy.