Correlation of Computed Tomography Test Bolus Dynamics and Conventional Computed Tomography Parameters With Pulmonary Vascular Resistance in Patients With Pulmonary Arterial Hypertension.

OBJECTIVE: Pulmonary vascular resistance (PVR) is a measurement obtained with invasive right heart catheterization (RHC) that is commonly used for management of patients with pulmonary arterial hypertension (PAH). Computed tomography pulmonary angiography (CTPA) is also done as part of the workup for PAH in some cases. The aim of our study was to assess the correlation of contrast dynamic changes in the main pulmonary artery (MPA) on CTPA with PVR obtained with RHC. METHODS: This is an IRB-approved retrospective study performed in two separate institutions (Medical College of Wisconsin and University of Alabama) between January 2010 and December 2013. During CTPA done as test bolus, serial images are acquired at the level of MPA after intravenous injection of contrast to determine timing of the CT acquisition. Since the PVR changes with the degree of PAH, we hypothesize that will be reflected in the contrast kinetics in MPA. A correlation of standard CT metrics (MPA diameter, right pulmonary artery [PA] diameter, left PA diameter, MPA/aorta ratio, and right ventricle/left ventricle [RV/LV] ratio) and dynamic (full width at half maximum) CTPA parameters in patients with known PAH was performed with PVR obtained from RHC done within 30 days. Statistical analysis was performed by Pearson correlation coefficient. RESULTS: Among 221 patients in our database, 37 patients fulfilled the selection criteria. There was a strong correlation between full width half maximum (FWHM) and mean pulmonary artery pressure (mPAP) (r=0.69, p value<0.00001), PVR (r=0.8, p value<0.00001) and indexed PVR (PVRI) (r=0.75, p value<0.00001). CONCLUSION: FWHM obtained from CTPA strongly correlates with RHC parameters and is potentially more helpful than static measurements for follow-up of patients with known PAH to assess response to treatment or progression.

Imaging of Pulmonary Hypertension in Adults: A Position Paper from the Fleischner Society.

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mm Hg and classified into five different groups sharing similar pathophysiologic mechanisms, hemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: (a) Is noninvasive imaging capable of identifying PH? (b) What is the role of imaging in establishing the cause of PH? (c) How does imaging determine the severity and complications of PH? (d) How should imaging be used to assess chronic thromboembolic PH before treatment? (e) Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH. This article is a simultaneous joint publication in Radiology and European Respiratory Journal. The articles are identical except for stylistic changes in keeping with each journal's style. Either version may be used in citing this article. © 2021 RSNA and the European Respiratory Society. Online supplemental material is available for this article.

Imaging of pulmonary hypertension in adults: a position paper from the Fleischner Society.

Pulmonary hypertension (PH) is defined by a mean pulmonary artery pressure greater than 20 mmHg and classified into five different groups sharing similar pathophysiologic mechanisms, haemodynamic characteristics, and therapeutic management. Radiologists play a key role in the multidisciplinary assessment and management of PH. A working group was formed from within the Fleischner Society based on expertise in the imaging and/or management of patients with PH, as well as experience with methodologies of systematic reviews. The working group identified key questions focusing on the utility of CT, MRI, and nuclear medicine in the evaluation of PH: a) Is noninvasive imaging capable of identifying PH? b) What is the role of imaging in establishing the cause of PH? c) How does imaging determine the severity and complications of PH? d) How should imaging be used to assess chronic thromboembolic PH before treatment? e) Should imaging be performed after treatment of PH? This systematic review and position paper highlights the key role of imaging in the recognition, work-up, treatment planning, and follow-up of PH.

Pulmonary vein thrombosis in patients with medical risk factors.

Pulmonary vein thrombosis in patients with medical illnesses has been rarely reported, and it is also rarely reported in those with no risk factors. We report 2 patients with pulmonary vein thrombosis, 1 with metastatic renal cell carcinoma and 1 with presumed pulmonary aspergillosis. Thrombi or tumors in a pulmonary vein are clinically important because they may cause systemic embolism or hemoptysis.

Thoracostomy tube function not trajectory dictates reintervention.

BACKGROUND: Hemothorax and/or pneumothorax can be managed successfully managed with tube thoracostomy (TT) in the majority of cases. Improperly placed tubes are common with rates near 30%. This study aimed to determine whether TT trajectory affects the rate of secondary intervention. METHODS: A retrospective review of all adult trauma patients undergoing TT placement over a 4-y period was performed. TT trajectory was classified as ideal, nonideal, or kinked-based on anterior-posterior chest x-ray. TTs with sentinel port outside the thoracic cavity were excluded. The primary outcome was any secondary intervention. RESULTS: Four-hundred eighty-six patients and a total of 547 hemithoraces underwent placement and met inclusion criteria. The majority of patients were male (76%), with a median age of 41 y, and majority suffered blunt trauma ideal trajectory was identified in 429 (78.4%). Kinked TTs were noted in 33 (6%) hemothoraces with a 45.5% replacement rate. Review with staff demonstrates inherent bias to replace kinked TTs. The overall secondary intervention rate was 27.8%. Kinked TTs were removed from final analysis due to treatment bias. Subsequent analysis demonstrated no significant difference between ideal and nonideal trajectories (25.1% versus 34.1%, P = 0.09). CONCLUSIONS: Intrathoracic trajectory of nonkinked TTs with the sentinel port within the thoracic cavity does not affect secondary intervention rates, including the rate of surgical intervention.

Reduced z-axis technique for CT Pulmonary angiography in pregnancy--validation for practical use and dose reduction.

The aim of this study is to determine the feasibility of using reduced scan range CT pulmonary angiography technique in pregnancy for pulmonary embolism (PE) and to quantify resulting dose reduction. This was a retrospective study. Eighty-four CTPA exams performed on pregnant women during 2004-2012. The scans were modified to create reduced anatomic coverage scans extending from aortic arch to base of heart. These were separately evaluated by two radiologists for PE and non-PE abnormalities. The results were then compared by the third radiologist with original radiology report and scans. Radiation dose reduction was evaluated prospectively in 36 patients as part of a quality control project. Two patients had PE and were successfully identified on reduced z-axis scans. Thirty-two exams were normal; rest had 60 pertinent and 16 had incidental findings. There were four incidental findings which included three benign thyroid nodules and one benign small lung nodule which were missed. None of these affected clinical outcome or management. There was 71 % radiation dose reduction. No PE or any important diagnoses are missed using reduced z-axis CTPA in pregnancy. There is a substantial radiation dose reduction. Hence, this technique is highly recommended in pregnancy.

The azygos vein pathway: an overview from anatomical variations to pathological changes.

The azygos venous system represents an accessory venous pathway supplying an important collateral circulation between the superior and inferior vena cava. The aim of this article is to revise the wide spectrum of changes ranging from normal to pathological conditions involving the azygos system. Teaching points • The azygos vein is a collateral venous pathway, becoming a vital shunt if major pathways of venous return are obstructed. • In azygos continuation, the azygos vein becomes significantly enlarged due to inferior vena cava interruption. • Fibrosing mediastinitis is an underestimated acquired disorder. • Fibrosing mediastinitis induces a variable engorgement of collateral veins. • Fibrosing mediastinitis leads to superior vena cava syndrome.

Dose reduction of 69% for computed tomography pulmonary angiography: reduced z-axis computed tomography pulmonary angiography retains accuracy in those younger than 40 years.

OBJECTIVE: We sought to determine whether reduced scan range (z axis) computed tomography pulmonary angiography (CTPA) technique in 18- to 40-year age group can accurately detect pulmonary embolism (PE) and other important conditions and to quantify the resulting dose reduction. METHODS: We retrospectively identified 200 patients in the age group of 18 to 40 years who underwent CTPA over a period of 3 years. These included 86 patients with PEs and 114 randomly selected patients negative for PE (control subjects). The scans were modified by reducing the scan coverage by eliminating images above the aortic arch and below the base of the heart. Two blinded experienced radiologists rescored them for PE and incidental and pertinent non-PE findings. Discrepancies between these and the original report were assessed by a third experienced radiologist. Separately, a departmental quality-control project was conducted in 15 patients to assess the dose length product along the z axis across the 3 zones of thorax. RESULTS: Pulmonary embolism was diagnosed in all 86 patients. No pertinent additional findings were missed. Only 7 incidental findings were missed (eg, benign thyroid nodules [n = 4], benign adrenal adenoma [n = 1], gallstones [n = 1], and hepatic hemangioma [n = 1]). None affected clinical outcome or management. Dose length product was reduced by a mean of 69% (60%-79%). CONCLUSIONS: Reduced z-axis CTPA for PE is definitely feasible in 18- to 40-year age group. There is a significant radiation reduction (69%) and hence should be considered in selected subgroups of patients.

In search of venous thromboembolism: the first 2913 years.

OBJECTIVE: Venous thromboembolism was first described in India around 600-900 BC. It was not until the 17th through 19th centuries that Western researchers began to understand the anatomy, physiology, and pathology of deep venous thrombosis and pulmonary embolism. Roentgen's discovery of x-rays in 1895 led to the first objective imaging. CONCLUSION: Currently, scintigraphy, helical CT, MRI, and sonography provide accurate in vivo images. These high-quality images have forced clinicians to reevaluate many preimaging assumptions about and treatments for venous thromboembolism.

Use of combination chemotherapy for treatment of granulomatous and lymphocytic interstitial lung disease (GLILD) in patients with common variable immunodeficiency (CVID).

PURPOSE: A subset of patients with common variable immunodeficiency (CVID) develops granulomatous and lymphocytic interstitial lung disease (GLILD), a restrictive lung disease associated with early mortality. The optimal therapy for GLILD is unknown. This study was undertaken to see if rituximab and azathioprine (combination chemotherapy) would improve pulmonary function and/or radiographic abnormalities in patients with CVID and GLILD. METHODS: A retrospective chart review of patients with CVID and GLILD who were treated with combination chemotherapy was performed. Complete pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT) scans of the chest were done prior to therapy and >6 months later. HRCT scans of the chest were blinded, randomized, and scored independently (in pairs) by two radiologists. The differences between pre- and post-treatment HRCT scores and PFT parameters were analyzed. RESULTS: Seven patients with CVID and GLILD met inclusion criteria. Post-treatment increases were noted in both FEV1 (p=0.034) and FVC (p=0.043). HRCT scans of the chest demonstrated improvement in total score (p=0.018), pulmonary consolidations (p=0.041), ground-glass opacities (p=0.020) nodular opacities (p=0.024), and both the presence and extent of bronchial wall thickening (p=0.014, 0.026 respectively). No significant chemotherapy-related complications occurred. CONCLUSIONS: Combination chemotherapy improved pulmonary function and decreased radiographic abnormalities in patients with CVID and GLILD.

Power injectable peripherally inserted central venous catheter lines frequently flip after power injection of contrast.

OBJECTIVE: To determine the frequency of power injectable peripherally inserted central venous catheter (PIPICC) displacement after contrast injection for computed tomography. MATERIALS AND METHODS: We included all patients who had a computed tomographic examination with contrast administration via PIPICC over a 4-month period. Several variables including catheter location before and after the injection were documented. Descriptive statistics were used for continuous variables. The χ² test was used to compare groups. Continuous variables were analyzed using the Student t test. RESULTS: Among 78 injections in 67 patients (34 men and 33 women; median age, 49 years), there were 12 catheter displacements (15.4%): 5 (62.5%) of 8 catheters initially located proximal to the tracheobronquial angle (TBA) and 7 (10.14%) of 69 catheters initially located distal to the TBA. The initial catheter position before the injection correlated with the frequency of displacement significantly (P < 0.006). Contrast injection rate and amount of contrast were no risk factors for position change. There were no complications. CONCLUSION: Catheter displacement occurred in 62.5%, with PIPICCS cephalad to the TBA. A preliminary scout view should be checked before the contrast injection. In addition, a postinjection scan scout view is recommended to verify catheter position.

Fetal risk in diagnostic radiology.

It is not uncommon to encounter situations in which radiologic examinations are necessary for accurate diagnosis and effective treatment of an expectant mother. The potential deleterious health consequences to the developing embryo and fetus from in utero irradiation include fetal death, congenital malformations, growth retardation, and carcinogenic and mutagenic effects. The likelihood of each effect is greatly dependent on the radiation dose and the gestational age of the conceptus at the time of exposure. In general, the average fetal doses from diagnostic imaging are <50 mGy (5 rad) and have not been associated with any significant adverse fetal effects. However, each case should be evaluated on an individual basis, and the risks should be explained to the patient before the examination. In addition, every effort should be made to reduce the fetal dose to as low as reasonably achievable. The biological effects of in utero radiation exposure, estimated fetal doses from various radiologic examinations, and general guidelines regarding diagnostic imaging during pregnancy will be discussed in this article.

Signal quality of single dose gadobenate dimeglumine pulmonary MRA examinations exceeds quality of MRA performed with double dose gadopentetate dimeglumine.

During a recent multi-center trial assessing gadolinium (Gd)-enhanced magnetic resonance angiography (MRA) for diagnosis of acute pulmonary embolism (PE), the Food and Drug Administration announced a risk of nephrogenic sclerosing fibrosis in patients with renal insufficiency who had received intravenous Gd-based MR contrast agents. Although no patients in this trial had renal insufficiency, in cautious response to this announcement, the trial protocol was changed from an intravenous administration of 0.2 mmol/Kg of a conventional Gd-based MR contrast agent to 0.1 mmol/Kg of gadobenate dimeglumine. The study described herein compares the signal quality of pulmonary MRA performed with double dose conventional agent to single dose gadobenate dimeglumine. This study is a retrospective analysis of data from a prospective, multicenter study in men and women ≥18 years with documented presence or absence of PE. The study was approved by the Institutional Review Board at all participating centers, and all patients provided written indication of informed consent. We performed both objective and subjective analysis of pulmonary artery image quality. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the main pulmonary artery were assessed in single and double dose protocols and compared. SNR and CNR of the main PA were correlated with subjective quality assessment of main/lobar, segmental and subsegmental pulmonary arteries. Although there were individual outliers, both SNR (P = 0.01) and CNR (P = 0.008) were higher in all quartiles for examinations using gadobenate dimeglumine than with gadopentetate dimeglumine. Subjective quality of vascular signal intensity at each vessel order was significantly better for gadobenate dimeglumine (P < 0.0001), and correlated well with SNR and CNR at each order (<0.001). Because of agent high relaxivity, a single dose of gadobenate dimeglumine provides better pulmonary MRA signal quality than double dose of a conventional Gd-based MR contrast agent.

Diagnosis and management of isolated subsegmental pulmonary embolism: review and assessment of the options.

We assessed the potential safety of withholding treatment of pulmonary embolism (PE) limited to subsegmental branches. Literature review showed that untreated patients with mostly subsegmental PE had no fatal recurrences in 1 to 3 months and no nonfatal recurrences of PE in 3 months. Patients with suspected PE who had nondiagnostic ventilation/perfusion lung scans, adequate cardiorespiratory reserve or low or moderate clinical probability, and negative serial noninvasive leg tests were shown not to require treatment. It appears safe, therefore, to withhold treatment of subsegmental PE providing (1) pulmonary-respiratory reserve is good; (2) no evidence of deep venous thrombosis (DVT) on serial testing; (3) major risk factor for PE was transient and no longer present; (4) no history of central venous catheterization or atrial fibrillation; and (5) willingness to return for serial venous ultrasound. After fully informing patients, some may choose to be treated and some may choose not to be treated.

Factors in the technical quality of gadolinium enhanced magnetic resonance angiography for pulmonary embolism in PIOPED III.

In a multi-center trial, gadolinium enhanced magnetic resonance angiography (MRA) for diagnosis of acute pulmonary embolism (PE) had a high rate of technically inadequate images. Accordingly, we evaluated the reasons for poor quality MRA of the pulmonary arteries in these patients. We performed a retrospective analysis of the data collected in the PIOPED III study. We assessed the relationship to the proportion of examinations deemed "uninterpretable" by central readers to the clinical centers, MR equipment platform and vendors, degree of vascular opacification in different orders of pulmonary arteries; type, frequency and severity of image artifacts; patient co-morbidities, symptoms and signs; and reader characteristics. Centers, MR equipment vendor and platform, degree of vascular opacification, and motion artifacts influenced the likelihood of central reader determinations that images were "uninterpretable". Neither the reader nor patient characteristics (age, body mass index, respiratory rate, heart rate) correlated with the likelihood of determining examinations "uninterpretable". Vascular opacification and motion artifact are the principal factors influencing MRA interpretability. Some centers obtain better images more consistently, but the reasons for differences between centers are unclear.

Controversies in diagnosis of pulmonary embolism.

The approach to the diagnosis of acute pulmonary embolism (PE) is under constant revision with advances in technology, noninvasive approaches, and increasing awareness of the risks of ionizing radiation. Optimal approaches in some categories of patients are controversial. Data are insufficient for evidence-based recommendations. Therefore, this survey of investigators in the field was undertaken. Even among experts there were marked differences of opinion regarding the approach to the diagnosis of acute PE. Although CT pulmonary angiography was usually the imaging test of choice, the respondents were keenly aware of the dangers of ionizing radiation. In view of advances in scintigraphic diagnosis since the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) trial, ventilation/perfusion (V/Q) lung scans or perfusion scans alone and single photon emission computed tomography (SPECT) V/Q lung scans are often recommended. The choice depends on the patient's age, gender, and complexity of the findings on the plain chest radiograph.

Pulmonary embolism: optimizing the diagnostic imaging approach.

Venous thromboembolism is a common medical problem that can affect a wide range of patients. The clinical presentation ranges from minor, nonspecific signs and symptoms to severe clinical scenarios. The combination of objective pretest clinical probability, D-dimer testing, and imaging studies plays a critical role in its diagnosis. There are multiple imaging modalities to confirm or exclude the presence of pulmonary embolism and deep vein thrombosis, but, at present, computed tomography angiography is the most frequently used. Other imaging, however, is required for several subpopulations.