Successful visualization of pulmonary embolism using fluoroscopic video analysis in a patient with iodine contrast allergy: a case report

Background

Contrast-enhanced computed tomography (CT) is commonly used to diagnose pulmonary embolism (PE). However, a history of iodine contrast allergy presents a dilemma in the management of patients with PE. As an alternative approach, X-ray fluoroscopic video analysis has been recently reported to be useful in diagnosing PE.

Case summary

A 78-year-old man with dyspnoea of 1-month duration visited our hospital. His oxygen saturation was 89%, and echocardiography demonstrated right heart strain. We could not perform contrast-enhanced CT because the patient had a history of contrast allergy and refused to undergo premedicated contrast CT with anti-histamine and/or corticosteroid. Therefore, a video analysis of pulmonary circulation using dynamic chest X-ray (DCR) was performed. The reconstructed pseudo-colour video showed defects of pulmonary circulation in both lung areas. We diagnosed PE and started anticoagulant therapy. Multiple segmental defects were also observed in pulmonary perfusion scintigraphy on Day 3, which confirmed the diagnosis of PE. He was discharged on Day 9, and an improvement of the pulmonary circulation as assessed with DCR was observed. He had no symptoms at the last follow-up visit at 1 year after discharge.

Discussion

We describe the successful visualization of PE using DCR in a patient with iodine contrast allergy.

Dynamic perfusion digital radiography for predicting pulmonary function after lung cancer resection

Background

Accurate prediction of postoperative pulmonary function is important for ensuring the safety of patients undergoing radical resection for lung cancer. Dynamic perfusion digital radiography is an excellent and easy imaging method for detecting blood flow in the lung compared with the less-convenient conventional lung perfusion scintigraphy. As such, the present study aimed to confirm whether dynamic perfusion digital radiography can be evaluated in comparison with pulmonary perfusion scintigraphy in predicting early postoperative pulmonary function and complications.

Methods

Dynamic perfusion digital radiography and spirometry were performed before and 1 and 3 months after radical resection for lung cancer. Correlation coefficients between blood flow ratios calculated using dynamic perfusion digital radiography and pulmonary perfusion scintigraphy were then confirmed in the same cases. In all patients who underwent dynamic perfusion digital radiography, the correlation predicted values calculated from the blood flow ratio, and measured values were examined. Furthermore, ppo%FEV1 or ppo%DLco values, which indicated the risk for perioperative complications, were examined.

Results

A total of 52 participants who satisfied the inclusion criteria were analyzed. Blood flow ratios measured using pulmonary perfusion scintigraphy and dynamic perfusion digital radiography showed excellent correlation and acceptable predictive accuracy. Correlation coefficients between predicted FEV1 values obtained from dynamic perfusion digital radiography or pulmonary perfusion scintigraphy and actual measured values were similar. All patients who underwent dynamic perfusion digital radiography showed excellent correlation between predicted values and those measured using spirometry. A significant difference in ppo%DLco was observed for respiratory complications but not cardiovascular complications.

Conclusions

Our study demonstrated that dynamic perfusion digital radiography can be a suitable alternative to pulmonary perfusion scintigraphy given its ability for predicting postoperative values and the risk for postoperative respiratory complications. Furthermore, it seemed to be an excellent modality because of its advantages, such as simplicity, low cost, and ease in obtaining in-depth respiratory functional information.

Trial registration

Registered at UMIN on October 25, 2017. https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_his_list.cgi?recptno=R000033957

Registration number: UMIN000029716

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02158-w.

Quantification of nonuniform distribution of hemi-lung perfusion in chronic obstructive pulmonary disease

Nonuniform distribution (NUD) of perfusion on single photon emission computed tomography (SPECT) is caused by impaired perfusion-related fluctuations of the functional volume (FFV). It was determined if digital analysis of NUD in each hemi-lung damaged by chronic obstructive pulmonary disease (COPD) could improve the whole lung impairment assessment. We examined 665 subjects and 8 controls by SPECT. The basic whole lung SPECT volume was defined at 10% of maximum whole lung count cutoff threshold (T h). For the whole lung and each hemi-lung, the 10% T h width volume, FFV rate, and misfit from the control were calculated at every T h width number (n) from 1 to 9 for every additional 10% T h from 10 to 100%. The misfit value integrated from 1 to 9 of n was defined by 3 NUD indices: D, whole lung NUD index; D rl , the index for the sum of each hemi-lung NUD; and D (I) , the NUD index with every interpolating pattern in which FFV rates of hemi-lungs comprised negative and positive value at the same n. D rl index was the sum of D and D (I) indices in all patients. D rl and D indices significantly increased in pulmonary disease subjects relative to those of the normal group and non-pulmonary disease subjects. D rl and D indices increased in COPD subjects. Progressive COPD subjects had larger D rl index values and "diffuse and even" hemi-lung impairment. The three indices quantizing FFV itself leading to NUD helped to digitally evaluate the degree of lung impairment of perfusion. Clinically, it is expected that the NUD indices and images obtained by SPECT, which visually and digitally show the pathological fluctuations in perfusion caused by lung impairment, will be able to provide specific and useful information for improving treatment and/or care of subjects with COPD.