Transient interruption of contrast on CT pulmonary angiography: effect of mid-inspiratory vs. end-inspiratory respiration command

PURPOSE

To investigate the effects of mid-inspiratory respiration commands and other factors on transient interruption of contrast (TIC) incidence on CT pulmonary angiography.

METHODS

In this retrospective study, 824 patients (mean age, 66.1 ± 15.3 years; 342 males) who had undergone CT pulmonary angiography between January 2021 and February 2023 were included. Among them, 545 and 279 patients were scanned at end- and mid-inspiratory levels, respectively. By placing a circular region of interest, CT attenuation of the main pulmonary artery (CTMPA) was recorded. Associations between several factors, including patient age, body weight, sex, respiratory command vs. TIC and severe TIC incidence (defined as CTMPA < 200 and 150 HU, respectively), were assessed using logistic regression analyses with stepwise regression selection based on Akaike's information criterion.

RESULTS

Mid-inspiratory respiration command, in addition to patient age and lighter body weight, had negative association with the incidence of TIC. Only patient age, lighter body weight, female sex, and larger cardiothoracic ratio were negatively associated with severe TIC incidence. Mid-inspiratory respiration commands helped reduce TIC incidence among patients aged < 65 years (p = 0.039) and those with body weight ≥ 75 kg (p = 0.005) who were at high TIC risk.

CONCLUSION

Changing the respiratory command from end- to mid-inspiratory levels, as well as patient age and body weight, was significantly associated with TIC incidence.

Effects of Intravenous Infusion of Iodine Contrast Media on the Tracheal Diameter and Lung Volume Measured with Deep Learning-Based Algorithm

This study aimed to investigate the effects of intravenous injection of iodine contrast agent on the tracheal diameter and lung volume. In this retrospective study, a total of 221 patients (71.1 ± 12.4 years, 174 males) who underwent vascular dynamic CT examination including chest were included. Unenhanced, arterial phase, and delayed-phase images were scanned. The tracheal luminal diameters at the level of the thoracic inlet and both lung volumes were evaluated by a radiologist using a commercial software, which allows automatic airway and lung segmentation. The tracheal diameter and both lung volumes were compared between the unenhanced vs. arterial and delayed phase using a paired t-test. The Bonferroni correction was performed for multiple group comparisons. The tracheal diameter in the arterial phase (18.6 ± 2.4 mm) was statistically significantly smaller than those in the unenhanced CT (19.1 ± 2.5 mm) (p < 0.001). No statistically significant difference was found in the tracheal diameter between the delayed phase (19.0 ± 2.4 mm) and unenhanced CT (p = 0.077). Both lung volumes in the arterial phase were 4131 ± 1051 mL which was significantly smaller than those in the unenhanced CT (4332 ± 1076 mL) (p < 0.001). No statistically significant difference was found in both lung volumes between the delayed phase (4284 ± 1054 mL) and unenhanced CT (p = 0.068). In conclusion, intravenous infusion of iodine contrast agent transiently decreased the tracheal diameter and both lung volumes.

Deformed Popliteal Artery Due to Highly Flexed Knee Position Can Cause Kinks, Creating an Unfavorable Hemodynamic State

BACKGROUND

Endovascular treatment devices of the femoropopliteal artery have evolved, improving clinical results. However, the effects of dynamic changes in the popliteal artery during knee flexion have not been sufficiently investigated. In this study we performed a 3-dimensional analysis to clarify the dynamic changes in the popliteal artery during knee flexion and their effects on hemodynamics.Methods and Results: To analyze dynamic changes in the popliteal artery in the knee flexion position, a computed tomography protocol was developed in the right-angled and maximum flexion knee positions. Thirty patients with lower extremity artery disease were recruited. V-Modeler software was used for anatomical and hemodynamic analyses. Various types of deformations of the popliteal artery were revealed, including hinge points and accessory flexions. Kinks can occur in the maximum flexion position; however, they rarely occur in the right-angled flexion position. In addition, hemodynamic analysis revealed a tendency for lower minimum wall shear stress and a higher maximum oscillatory shear index at the maximum curvature of the popliteal artery.

CONCLUSIONS

Kinks in the maximum flexion position suggested that the outcome of endovascular treatment may change in areas such as Japan, where knee flexion is customary. Hemodynamics at the maximum curvature of the popliteal artery indicated that the luminal condition was unfavorable for endovascular treatment.

Clinical valve thrombosis and arterial embolism in a cancer patient after transcatheter aortic valve replacement

The number of cancer patients with severe aortic stenosis and atrial fibrillation (AF) is increasing in the aging population. Transcatheter aortic valve replacement (TAVR) is an established treatment option for severe aortic stenosis with high surgical risk, including individuals with cancer. Antithrombotic therapy should be considered for post-TAVR or AF patients. However, antithrombotic management in cancer patients remains challenging due to the increased risk of both thromboembolism and bleeding. We present a case of clinical valve thrombosis and arterial embolism after transcatheter aortic valve replacement in an elderly patient with a history of metastatic pancreatic cancer and permanent atrial fibrillation under treatment of single antiplatelet therapy. Warfarin treatment after successful surgical thrombectomy to the occluded arteries improved clinical valve thrombosis, although the long-term outcome remains unclear. This case demonstrates that novel management algorithms for thromboembolism and bleeding in elderly cancer patients with AF and valvular heart disease are urgently needed.

Structural Characterization of 6-Thioguanosine and Its Monohydrate in the Gas Phase

Detailed structural analysis of 6-thioguanosine (6TGs) in relation to its tautomerization and sugar conformation is performed in the gas phase using UV and IR spectroscopy combined with ab initio calculations. We have observed a thiol tautomer of 6TGs with its sugar moiety in the syn conformation that is stabilized by a strong intramolecular H-bonding between O5'H of the sugar and N3 atom of the guanine moiety. This observation is consistent with previous results for guanosine (Gs) in which the corresponding enol form is solely detected. We have also identified a monohydrate of 6TGs consisting of a thiol tautomer with the water linking guanine moiety and sugar OH group. It is demonstrated that hydration behavior of 6TGs is significantly different from that of Gs as a result of a weaker H-bonding ability of the thiol group.

Hydrogen-bonding interactions of uric acid complexes with water/melamine by mid-infrared spectroscopy

Hydrogen (H)-bonding interactions of uric acid (UA) with water have been investigated via IR-UV double resonance measurements in the mid-IR region. Comparison of the present results with those obtained previously in the near-IR region enables us to examine microscopic hydration effects that are specific to the H-bonding acceptor sites of UA. It is shown that hydration of the C8O site promotes the mode coupling of this stretch with the C2O stretch. The occurrence of this coupling is manifested in the IR intensity pattern, in which the transition associated with the in-phase contribution C8O + C2O is significantly suppressed, whereas the corresponding out-of-phase contribution gives rise to a strong peak. We also measured the mid-IR spectra of the 1 : 1 complex formed between UA and melamine (MEL) and carried out a structural analysis using the spectroscopic signature of the H-bonding derived from the result of the monohydrated cluster. It is shown that the complex possesses a triple H-bonding structure with the C2O acceptor site of UA H-bonded to MEL. Furthermore, the IR-depleted UV spectroscopy technique was employed in order to ascertain whether other structural isomers are present in the probe UV spectra.

Ab initio studies on the photophysics of uric acid and its monohydrates: role of the water molecule

The photophysical behavior of three lowest-energy tautomers of uric acid and seven most stable isomers of uric acid monohydrate is comprehensively studied by ab initio calculations. Ground-state energies are calculated with the CCSD(T) method, while excitation and ionization energies as well as excited-state potential energy profiles of photoinduced processes are calculated with the CC2 method. For the (1)ππ* state, it is found that the excitation energy of the monohydrate cluster is significantly lower than that of isolated uric acid when the water molecule is hydrogen-bonded at a specific carbonyl group. The calculated excited-state potential energy profiles suggest that some monohydrate isomers can undergo a migration of the water molecule from one site to another site in the (1)ππ* state with a small energy barrier. It is also found for both uric acid and its monohydrate that nonradiative decay via the NH bond dissociation in the (1)πσ* state is likely to occur at higher excitation energies. On the basis of the computational results, possible mechanisms for the absence of specific isomers of uric acid monohydrate from the resonant two-photon ionization spectrum are discussed.

Controlling Glycosyl Bond Conformation of Guanine Nucleosides: Stabilization of the anti Conformer in 5'-O-Ethylguanosine

Nucleosides that consist of base and sugar moieties can adopt two main conformations, syn and anti, about the glycosidic bond. We have investigated the conformational properties of guanine nucleosides in the gas phase by using laser desorption combined with IR-UV double resonance spectroscopy. In guanosine, syn conformation is preferred as a result of internal hydrogen bonding between the 5'-OH group of the sugar and the N3 site of the guanine moiety. We have therefore employed a chemically modified nucleoside 5'-O-ethylguanosine, in which possible glycosyl bond conformations are restricted upon ethylation of the 5'-OH group. The result shows that anti conformer is stabilized by the formation of hydrogen bonding involving the 2'-OH group.

Gas-phase isolation of diethyl guanosine 5'-monophosphate and its conformational assignment

We show that intact neutral molecules of guanosine 5'-monophosphate can be vaporized by laser desorption when its phosphate group is esterified. The UV and IR spectroscopic measurements of this nucleotide reveal the existence of a novel internal hydrogen-bonding conformation of the phosphate group and guanine moiety.

Eosinophil chemoattractants in the middle ear of patients with eosinophilic otitis media

BACKGROUND

Patients with intractable otitis media associated with bronchial asthma have an extensive accumulation of eosinophils in the effusion and mucosa of the middle ear; this condition is called eosinophilic otitis media (EOM). It remained to be determined how eosinophils accumulate in the middle ear.

OBJECTIVES

To clarify the pathogenesis of middle ear diseases, we measured the concentration of eosinophil chemoattractants in middle ear effusion (MEE), and carried out immunohistochemical studies of middle ear mucosa specimens to demonstrate the expression of eosinophil chemoattractants.

METHODS

Middle ear effusion samples were obtained from 15 EOM patients with bronchial asthma and from six controls for the measurement of eosinophil cationic protein (ECP), IL-5, eotaxin and regulated on activation, normal T expressed and secreted concentrations. Middle ear mucosa samples were also taken from 14 EOM patients and 16 controls for immunohistochemical study. In 10 EOM patients, the numbers of immunoreactive cells as well as apoptotic cells were determined before and after the topical application of triamcinolone acetonide into the middle ear.

RESULTS

In EOM, significantly higher ECP and IL-5 concentrations were detected in MEE than in serum, and ECP, IL-5 and eotaxin concentrations in MEE were higher in the EOM patients than in the controls. ECP concentration positively correlated with that of IL-5. Immunohistochemically, the numbers of cells positive for EG2 and ecalectin were significantly higher in the EOM patients than in the controls. After the topical application of triamcinolone acetonide, the numbers of infiltrating cells and immunoreactive cells distinctly decreased, whereas the number of apoptotic cells significantly increased.

CONCLUSION

In EOM, locally produced IL-5 may play a crucial role in the accumulation of eosinophils in the middle ear. Chemokines such as ecalectin and eotaxin are also produced in the middle ear, and help activate and enhance the survival of eosinophils to induce the intractable condition in the middle ear. The topical application of triamcinolone acetonide induces the apoptosis of not only eosinophils but also eosinophil chemoattractant-producing cells, thereby improving the middle ear condition.

Expression of ecalectin, a novel eosinophil chemoattractant, in nasal polyps

CONCLUSION

Ecalectin, which is produced in the mucosa of nasal polyps, seems to play an important role in the accumulation and activation of eosinophils in nasal polyps, regardless of the presence or absence of atopic predisposition.

OBJECTIVE

Ecalectin is a recently discovered eosinophil chemoattractant which elongs to the galectin family. We investigated the expression of ecalectin in nasal polyp tissues associated with various nasal and paranasal diseases in order to clarify the pathogenesis of eosinophilia in nasal polyposis.

MATERIAL AND METHODS

Nasal polyps were taken from 56 patients diagnosed as having chronic sinusitis with nasal polyposis. The surgically resected polyps and nasal turbinates were immunohistochemically stained using antibodies against EG2, human mast cell tryptase, CD3 and ecalectin.

RESULTS

The number of EG2- and ecalectin-positive cells was significantly higher in nasal polyps than control turbinates. Ecalectin-positive cells were observed in the subepithelial layer, where many EG2-positive cells were present. The number of ecalectin-positive cells correlated significantly with the number of EG2-positive cells in nasal polyps. Many ecalectin mRNA-positive cells were also observed in nasal polyps with an accumulation of EG2-positive cells.

[Laryngeal manifestations of gastroesophageal reflux disease (GERD) in pediatric patients: the usefulness of therapeutic (proton pump inhibitor (PPI)) trials]

Gastroesophageal reflux, common in infants, usually resolves spontaneously by 12 to 18 months. Gastroesophageal reflux disease (GERD) contributes to certain respiratory symptoms, but is reported to be due to other causal diseases, such as tracheolaryngeal anomaly, congenital esophageal hiatal hernia, and cerebral palsy, in pediatric patients. We report 4 pediatric cases with unusual laryngeal disorders, especially posterior glottic lesion, induced by gastroesophageal reflux without other causal disease. Subject 1 was a 1-year-old boy showing severe laryngeal spasm, Subject 2 a 3-year-old boy with life-threatening supraglottic stenosis, Subject 3 a 5-year-old boy whose voice had reached near aphonia with multiple laryngeal granulomatous lesions, and Subject 4 an 8-year-old boy with persistent abnormal throat sensations. Their symptoms were recalcitrant to conventional therapy. Their case histories (much belching and hiccups) and findings for the posterior glottitis, etc., suggested that symptoms might be induced by GERD, but, barium esophagography and esophagoscopy provided no conclusive proof. We could not monitor their ph because of the excessive physical and psychological stress involved. After therapeutic trials with a proton pump inhibitor (lansoprazole 10-15 mg) for 8 weeks, all had recovered almost completely without side effects.

Morphological and histochemical studies of the genioglossus muscle

The purpose of this preliminary study was to assess the histo-anatomic composition of the genioglossus muscle fibers. The genioglossus muscles were obtained from 4 cadavers and 1 autopsy specimen. On morphological study, the average diameters of the muscle fibers were seen to gradually increase, from the fibers that ran anteriorly to the dorsum of the tongue, to the fibers that ran posteriorly to the root of the tongue. Histochemical study revealed that type II fibers were significantly predominant in the anterior portion; there was no dominant fiber type in the posterior portion. Gradual changes in diameter were independent of fiber type. These findings may suggest that the fibers of the anterior portion are suitable for phasic action, and that the posterior is relatively tonic; and the posterior has larger absolute muscle strength than the anterior. It is thought that the fibers of the posterior portion might contribute to the maintenance of the mesopharyngeal airway and to vowel production, and that the anterior fibers might contribute to some fine movements and to consonant production.

["Direct" indirect training approach to rehabilitation of dysphagia patients--a new method for rehabilitation with a feeding-tube]

The rehabilitation approaches for training patients with dysphagia consist of both direct approaches (eating training) and indirect approaches (basic training for dysphagia patients without food). On the other side, some recent reports revealed that some patients who had had severe dysphagia were improved while the feeding approach was with a naso-gastic tube and an oral-esophago feeding tube. So we thought that stimulation of these feeding tubes for the pharynx and the larynx would produce some useful reactions for dysphagia patients. We developed a new method for the rehabilitation of such patients. The technique is the repeated insertion of the naso-gastric tube at the time of the swallowing motion, which we called the "direct" indirect training approach. Sometimes, other basic training procedures for dysphagia patients are admissible. We treated 26 patients by this method. The patients included those with disorders of the corticobulbar tract (n = 11), a disorder of the medulla (n = 5), a disorder of the peripheral nerve (n = 7), and a long-lasting disused state (n = 3). Twenty-four patients were improved and could eat orally without major problems. Laryngeal elevation curves of this approach in the pre- and post-therapeutic states revealed that the threshold of the swallowing reflux was lower, and the swallowing actions were changed dynamically, and became more useful.

[Relationship between oral food intake and nausea caused by intravenous injection of iodinated contrast material]

From December, 1990 to July, 1992 we investigated the relationship between the time after oral food intake and nausea and vomiting caused by the intravenous injection of iodinated contrast media in 2,414 patients who underwent contrast enhanced CT. The contrast media used were as follows: amidotrizoic acid (high-osmolality contrast medium, HOCM, iodine 292 mg/ml) in 1173 patients, iopamidol (low-osmolality contrast medium, LOCM, iodine 300m g/ml) in 641 patients, and iohexol (LOCM, iodine 300 mg/ml) in 600 patients. All the patients had an intravenous injection of 100ml in volume. The overall incidence of nausea and vomiting was 3.8% (96/2412 patients). The incidence was 6. 7% (79/1173 patients) in the HOCM group and 1.4% (17/1241 patients) in the LOCM group. The incidence of nausea and vomiting increased with the interval between the oral intake of food and the intravenous injection of contrast medium. It is concluded that fasting before contrast-enhanced CT enhances the adverse effect of nausea and vomiting.