Technical Quality and Diagnostic Impact of Chest X-rays in Tuberculosis Screening: Insights From a Saudi Teleradiology Cohort.

Objectives To assess the standard of chest X-ray techniques in tuberculosis (TB) screening within Saudi Arabian healthcare facilities and evaluate the impact of technical quality on radiological interpretation. Materials and methods Analysis of 250 posteroanterior chest radiographs sourced from a network of five clinics was conducted. These images were scrutinized for technical quality by a radiologist. Results Of the radiographs analyzed, 57% exhibited technical issues, with overexposure and clothing artifacts being the most commonly encountered. Notably, only 14% of these radiographs were deemed to have compromised diagnostic ability. Conclusion The presence of technical issues in most chest X-rays for TB screening highlights a significant area for improvement. However, the relatively low percentage of radiographs impacting diagnostic quality indicates that most issues do not critically hinder the radiologist's interpretative capability. This underscores the importance of balanced quality control measures in radiographic practices for effective TB detection in the region.

Comparing Two Methods of Aortic Annulus Computed Tomography Measurements: A Retrospective Teleradiology Saudi Study.

Objectives The objective of this study was to determine the overall mean size of the aortic valve annulus and to compare two distinct methods of quantifying aortic valve annulus dimensions using computed tomography (CT) in pre-transcatheter aortic valve implantation (TAVI) Saudi teleradiology cohort. Materials and methods This retrospective cohort study, conducted from December 2019 to September 2023, included 31 patients identified using "TAVI" in our teleradiology picture archiving and communication system. CT examinations followed standardized protocols. Three experienced radiologists assessed the aortic valve annulus, measuring maximum, minimum, and mean transverse diameters, area, and area-derived diameter. The statistical analysis involved calculating mean values and standard deviations and conducting t-tests to compare measurement methods. Results The study cohort had an average age of 73.35 ± 8.55 years, with 67.74% males. No significant age difference was observed between genders (p = 0.8421). Aortic valve annulus measurements showed the mean transverse diameter to be 22.51 ± 2.04 mm and the area-derived diameter at 22.83 ± 1.99 mm, with no significant difference between these methods (p = 0.53). Additional parameters included the maximum transverse measurement (25.78 ± 2.92 mm), minimum transverse measurement (19.23 ± 2.31 mm), and area (4.12 ± 0.72 cm²). Conclusion This study employed mean and area-derived diameter methods to evaluate the average size of the aortic valve annulus within a Saudi teleradiology cohort. The average sizes determined were 22.51 mm and 22.83 mm for the mean and area-derived diameter methods, respectively. The lack of a statistically significant difference between these two methods suggests their comparable efficacy in assessing aortic valve annulus size in this cohort.

Sinusitis and its association with deviated nasal septum at a tertiary hospital: A retrospective study.

Objectives: Sinusitis is common and deviated nasal septum (DNS) is a frequent anatomical variant in the paranasal sinuses (PNS). Whether DNS can cause sinusitis has been a subject of debate. This study determined the rate of sinusitis and its possible association with DNS and other factors in patients attending King Abdulaziz University Hospital (KAUH). Methods: We conducted a hospital-based cross-sectional study and reviewed the electronic health records of KAUH retrospectively. We recruited all patients aged ≥18 years who were referred to the Diagnostic Radiology Department for a PNS computed tomography scan from January 2018 to December 2020. Descriptive and inferential statistics were calculated. Results: A total of 676 participants met the eligibility criteria, with a mean (SD) age of 38.9 (13) years. Sinusitis was present in 47.5% of patients, 54.8% ofwhich were males. Patients aged 31-40 years suffered sinusitis more than the other age groups.Approximately three-fourths (75.1%) of the total sample had DNS, and 51.3% of them had sinusitis. Those who did not have DNS but had sinusitis were 27.8%.There were significant associations between sinusitis and both sex (P <0.001) and age (P <0.05). Patients with DNS were approximately three times more likely to have sinusitis than those without DNS (OR =2.74, 95% CI:1.86-4.04; P <0.001). Conclusion: Almost half of the patients had sinusitis, and three-fourths had DNS. Sex, age, and DNS are possible factors associated with sinusitis. Assessing the presence of DNS and correcting it, if possible, is recommended to prevent the occurrence of sinusitis.

Revisiting Middle East Respiratory Coronavirus (MERS-CoV) Outbreak Chest Radiographic Initial Findings, Temporal Progression, and Correlation to Outcomes: A Multicenter Study.

Objectives Accounts of initial and follow-up chest X-rays (CXRs) of the Middle East respiratory coronavirus (MERS-CoV) patients, and correlation with outcomes, are sparse. We retrospectively evaluated MERS-CoV CXRs initial findings, temporal progression, and outcomes correlation. Materials and methods Fifty-three real-time reverse-transcriptase-polymerase chain reaction (rRT-PCR)-confirmed MERS-CoV patients with CXRs were retrospectively identified from November 2013 to October 2014. Initial and follow-up CXR imaging findings and distribution were evaluated over 75 days. Findings were correlated with outcomes. Results Twenty-two of 53 (42%) initial CXRs were normal. In 31 (68%) abnormal initial CXRs, 15 (48%) showed bilateral non-diffuse involvement, 16 (52%) had ground-glass opacities (GGO), and 13 (42%) had peripheral distribution. On follow-up CXRs, mixed airspace opacities prevailed, seen in 16 (73%) of 22 patients 21-30 days after the initial CXRs. Bilateral non-diffuse involvement was the commonest finding throughout follow-up, affecting 16 (59%) of 27 patients 11-20 days after the initial CXRs. Bilateral diffuse involvement was seen in five (63%) of eight patients 31-40 days after the initial CXRs. A bilateral diffuse CXR pattern had an odds ratio for mortality of 13 (95% CI=2-78) on worst and 18 (95% CI=3-119) on final CXRs (P-value <0.05). Conclusion Initially, normal CXRs are common in MERS-CoV patients. Peripherally located ground-glass and mixed opacities are common on initial and follow-up imaging. The risk of mortality is higher when bilateral diffuse radiographic abnormalities are detected.

Magnetic resonance imaging in the management of Crohn's disease: a systematic review and meta-analysis.

OBJECTIVES: Crohn's disease (CD) is a condition that can occur in any part of the gastrointestinal tract, although usually forms in the colon and terminal ileum. Magnetic resonance imaging (MRI) has become a beneficial modality in the evaluation of small bowel activity. This study reports on a systematic review and meta-analysis of magnetic resonance enterography for the prediction of CD activity and evaluation of outcomes and possible complications. METHODS: Following the PRISMA guidelines, a total of 25 low-risk studies on established CD were selected, based on a QUADAS-II score of ≥ 9. RESULTS: A sensitivity of 90% was revealed in a pooled analysis of the 19 studies, with heterogeneity of χ2 = 81.83 and I2 of 80.3%. Also, a specificity of 89% was calculated, with heterogeneity of χ2 = 65.12 and I2 of 70.0%. CONCLUSION: It was concluded that MRI provides an effective alternative to CT enterography in the detection of small bowel activity in CD patients under supervision of radiologist for assessment of disease activity and its complications. Its advantages include the avoidance of radiation exposure and good diagnostic accuracy.

Thoracic Diseases With Musculoskeletal Manifestations and Vice Versa: A Review.

OBJECTIVE: The purpose of this article is to review several thoracic conditions that are associated with certain musculoskeletal radiological abnormalities using imaging of patients with concomitant chest and musculoskeletal manifestations as illustrative examples. CONCLUSION: Radiologic findings of many thoracic diseases are often nonspecific. When standing alone, their interpretation commonly results in long differential diagnosis. However, in certain instances, a reasonably accurate diagnosis can be made based on imaging findings alone.

Low-dose attenuation correction in diagnosis of non-alcoholic fatty liver disease.

BACKGROUND: Non-enhanced computed tomography (CT) is a valuable modality in the diagnosis of non-alcoholic fatty liver disease (NAFLD). However, it is not clear if low-dose CT attenuation correction (CTAC) scans have the same accuracy to diagnose NAFLD. Our aim is to evaluate the diagnostic accuracy of low-dose CTAC in the diagnosis of NAFLD using non-enhanced CT as a gold standard. METHODS: A total of 864 patients who underwent a clinically indicated hybrid nuclear imaging scanning between May 2011 and April 2014 were included in the study. Diagnosis of fatty liver was established if an absolute liver attenuation was <40 Hounsfield units and/or a liver-to-spleen ratio was <1.1. The diagnostic accuracy parameters were calculated to detect NAFLD by low-dose CTAC using unenhanced CT as a gold standard. RESULTS: The prevalence of fatty liver by diagnostic CT and low-dose attenuation correction were 9.9 and 12.9% (using liver attenuation <40HU and liver-to-spleen ratio <1.1), respectively, with 32.9 and 34.9% (using absolute liver attenuation or ratio-to-spleen criteria), correspondingly. Low-dose CTAC had sensitivity (81.3%), specificity (94.0%), positive predictive value (60.2%), and negative predictive value (97.8%) using both diagnostic criteria. Using either of the diagnostic criteria resulted in sensitivity (76.8%), specificity (83.5%), PPV (66.3%), and NPV (89.5%). CONCLUSION: Low-dose CT could be used as a tool to rule out the presence of fatty liver if neither liver attenuation of less than 40 HU nor liver-to-spleen below 1.1 is present.

Aspiration-related organizing pneumonia complicating laparoscopic adjustable gastric banding: A lung cancer mimicker.

There are several described pulmonary complications due to laparoscopic adjustable gastric banding. We report a rare case of a 32-year-old male who presented with pulmonary symptoms and a solitary lung mass 12 years after laparoscopic adjustable gastric banding. A bronchoscopic lung biopsy showed organizing pneumonia that was induced by aspiration pneumonia. The atypical radiological appearance of the aspiration pneumonia may pose a diagnostic challenge, and clinicians' awareness regarding such an entity is needed to avoid unnecessary intervention.

Impact of Implementing Cardiac CT in Evaluating Patients Suspected of Cardioembolic Stroke.

BACKGROUND AND OBJECTIVES: In practice, clinical and logistic hurdles may hamper performing transesophageal echocardiography in stroke patients. Cardiac computed tomography (CT) is a recently introduced noninvasive modality able to detect various embolic causes. Thus, we retrospectively assessed possible added values of applying cardiac CT in the real-world work-up of suspected cardioembolic stroke cases. METHODS: Forty-seven patients were neurology service referrals for suspected cardioembolic stroke. The CT images and clinical reports of our cardiac CT radiologists were retrospectively evaluated. Cardiac CT was assessed in terms of detecting major embolic potential findings, potentially significant stroke-unrelated findings, and coronary arterial disease (CAD). Computed tomography results were correlated with echocardiographic reports. RESULTS: Cardiac CT showed findings of major embolic potential in 10 patients (21%, 5 thrombi cases, 2 vasculitis cases, 1 case of metastasis invading the left superior pulmonary artery, 1 myocardial infarction case, and 1 pulmonary arteriovenous malformations case), none of which were documented in echocardiography reports. Two cases (4%) with findings of major embolic potential where identified on echocardiography but not on CT (1 left atrial appendage thrombus and 1 mitral valve vegetation). Computed tomography of 13 patients (28%) showed 16 potentially significant stroke-unrelated findings. Twenty-one patients (47%) had unexpected CAD on CT, 11 (52%) of which were obstructive. CONCLUSIONS: Implementing cardiac CT in assessing patients suspected of cardioembolic stroke added value to echocardiographic evaluation, by detecting major embolic potential findings. In addition, cardiac CT revealed additional potentially significant stroke-unrelated findings and CAD.

High-pitch Helical Dual-source Computed Tomographic Pulmonary Angiography: Comparing Image Quality in Inspiratory Breath-hold and During Free Breathing.

PURPOSE: The purpose of this study was to compare qualitative and quantitative image parameters of dual-source high-pitch helical computed tomographic pulmonary angiography (CTPA) in breath-holding (BH) versus free-breathing (FB) patients. MATERIALS AND METHODS: Ninety-nine consented patients (61 female individuals; mean age±SD, 49±18.7 y) were randomized into BH (n=45) versus FB (n=54) high-pitch helical CTPA. Patient characteristics and CTPA radiation doses were analyzed. Two readers assessed for pulmonary embolism (PE), transient interruption of contrast, and respiratory and cardiac motion. The readers used a subjective 3-point scale to rate the pulmonary artery opacification and lung parenchymal appearance. A single reader assessed mean pulmonary artery signal intensity, noise, contrast, signal to noise ratio, and contrast to noise ratio. RESULTS: PE was diagnosed in 16% BH and 19% FB patients. CTPAs of both groups were of excellent or acceptable quality for PE evaluation and of similar mean radiation doses (1.3 mSv). Transient interruption of contrast was seen in 5/45 (11%) BH and 5/54 (9%) FB patients (not statistically significant, P=0.54). No statistically significant difference was noted in cardiac, diaphragmatic, and lung parenchymal motion. Lung parenchymal assessment was excellent in all cases, except for 5/54 (9%) motion-affected FB cases with acceptable quality (statistically significant, P=0.03). No CTPA was considered nondiagnostic by any of the readers. No objective image quality differences were noted between both groups (P>0.05). CONCLUSIONS: High-pitch helical CTPA acquired during BH or in FB yields comparable image quality for the diagnosis of PE and lung pathology, with low radiation exposure. Only a modest increase in lung parenchymal artifacts is encountered in FB high-pitch helical CTPA.

Helical computed tomography scanning of the larynx and upper trachea in rabbits.

BACKGROUND: Computed tomography (CT) is used to evaluate the human tracheobronchial tree because of its unsurpassed ability to visualize the airway and surrounding structures. To establish an ideal animal model for studying subglottic stenosis, we assessed the size and morphology of the normal rabbit's laryngotracheal airway by helical CT. We measured luminal dimensions at the levels of the arytenoid and cricoid cartilages and the first, third, and eighth tracheal rings. At all levels, the axial slices were used to calculate the maximum anteroposterior (AP) dimension, transverse dimension, and cross-sectional areas. We measured the tracheal length from the cricoid to the third and eighth tracheal rings on sagittal reformation. We assessed the hyoid, thyroid, cricoid, arytenoid, and tracheal rings for the presence of calcific or soft tissue densities. We also addressed the presence or absence of pre-epiglottic and paraglottic fat. RESULTS: The mean AP tracheal dimension ± standard deviation (SD) was 8.6 ± 0.5 mm at the arytenoid level, 8.2 ± 0.7 mm at the cricoid level, and 7.7 ± 0.2 mm at the first tracheal ring level. The transverse tracheal dimension ±SD was 5.3 ± 0.1 mm at the arytenoid level, 5.5 ± 0.5 mm at the cricoid level, and 6.1 ± 0.6 mm at the first tracheal ring level. The mean tracheal area ±SD was 35.7 ± 2.2 mm(2) at the arytenoid level, 35.8 ± 5.1 mm(2) at the cricoid level, and 39.2 ± 4.3 mm(2) at the first tracheal ring level. The tracheal length ±SD was 10.7 ± 2.3 mm from the cricoid to the third tracheal ring and 19.1 ± 1.14 mm to the eighth tracheal ring. There was complete calcification of the hyoid in all rabbits. Only two rabbits showed complete thyroid, arytenoid, or tracheal ring calcification. The remaining airway components were otherwise either uncalcified or partially calcified. The uvula, epiglottis, aryepiglottic fold, vallecula, piriform sinus, true/false vocal cords, and pre-epiglottic/paraglottic fat were not seen in any rabbit. CONCLUSIONS: Helical CT investigation provides good, highly definitive anatomic details of the larynx and trachea in rabbits. Such results may be used in further evaluation of the normal airway and in cases of subglottic stenosis.

Detectability of choledocholithiasis on CT: The effect of positive intraduodenal enteric contrast on portovenous contrast-enhanced studies.

BACKGROUND/AIM: To retrospectively assess the accuracy of intravenous (IV) contrast-enhanced multidetector CT (MDCT) in choledocholithiasis detectability, in the presence and absence of positive intraduodenal contrast. PATIENTS AND METHODS: Over a 3-year period, patients in whom endoscopic retrograde cholangiopancreatography (ERCP) was performed within a week from a portovenous (PV)-enhanced abdominal CT were identified. The final cohort consisted of 48 CT studies in which the entire common bile duct (CBD) length was visualized (19 males, 29 females; mean age, 68 years). We identified two groups according to the absence (n = 31) or presence (n = 17) of positive intraduodenal contrast. CT section thickness ranged from 1.25 to 5 mm. Two radiologists, blinded to clinical information and ERCP results, independently evaluated the CT images. Direct CBD stone visualization was assessed according to previously predefined criteria, correlating with original electronic CT reports and using ERCP findings as the reference standard. A third reader retrospectively reviewed all discordant results. The diagnostic performances of both observers and interobserver agreement were calculated for both groups. RESULTS: 77%-88% sensitivity, 50%-71% specificity, and 71%-74% accuracy were obtained in the group without positive intraduodenal contrast, versus 50%-80% sensitivity, 57%-71% specificity, and 59%-71% accuracy in the group with positive intraduodenal contrast. With the exception of the positive predictive value (PPV), all diagnostic performance parameters decreased in the positive intraduodenal contrast group, mostly affecting the negative predictive value (NPV) (71%-78% vs 50%-67%). CONCLUSION: PV-enhanced MDCT has moderate diagnostic performance in choledocholithiasis detection. A trend of decreasing accuracy was noted in the presence of positive intraduodenal contrast.

Middle East respiratory syndrome coronavirus (MERS-CoV) infection: chest CT findings.

OBJECTIVE: The purpose of this study was to describe the chest CT findings in seven patients with Middle East respiratory syndrome coronavirus (MERS-CoV) infection. CONCLUSION: The most common CT finding in hospitalized patients with MERS-CoV infection is that of bilateral predominantly subpleural and basilar airspace changes, with more extensive ground-glass opacities than consolidation. The subpleural and peribronchovascular predilection of the abnormalities is suggestive of an organizing pneumonia pattern.

A prospective randomized trial comparing image quality, study interpretability, and radiation dose of narrow acquisition window with widened acquisition window protocols in prospectively ECG-triggered coronary computed tomography angiography.

BACKGROUND: Prospectively triggered coronary computed tomography angiography (CTA) is commonly performed with a widened acquisition window to provide flexibility in image reconstruction. OBJECTIVE: We conducted a randomized controlled trial to determine whether the use of a narrow acquisition window in prospectively triggered coronary CTA would allow lower radiation dose while preserving image quality and interpretability. METHODS: Prospective 2-center 2- platform randomized trial that evaluated 205 consecutive patients 96 with widened acquisition (WA) and 109 narrow acquisition (NA) referred for coronary CTA in sinus rhythm and heart rate <65 beats/min. Patients scanned with WA had phases reconstructed at 5% intervals, and each phase was assigned an individual study ID. Images were reviewed with individual phase reconstructions interpreted randomly by 2 level 3 readers with a third for consensus. Images were evaluated with a 5-point Likert scale on a per-vessel basis (best score on any phase). Scores were then dichotomized into diagnostic (score 3-5) compared with nondiagnostic (score 1-2). Readers also reported obstructive coronary artery disease on a per-patient basis. Agreement for the diagnosis of obstructive disease and per-artery interpretability was performed. Signal and noise measurements were also performed. RESULTS: No difference in demographics between groups (P = NS). The signal-to-noise ratio was comparable 12.99 ± 3.4 NA and 12.53 ± 4.13 for the WA (P = 0.45). The median effective dose was 1.78 mSv for NA compared with 3.26 mSv for WA (P < 0.001). Image quality, diagnostic interpretability, interreader agreement, and downstream testing were not significantly different between the 2 groups (P= NS for all). CONCLUSIONS: Coronary CTA with NA resulted in a 47% lower radiation dose without significant difference in study interpretability or image quality or increased downstream resource use or testing.

Coronary computed tomography angiography for stable angina: past, present, and future.

Although the clinical use of computed tomography in cardiac imaging had slow beginnings, it has seen rapid development over the past decade. This review aims to discuss the state of the technology and to help clarify its role in the diagnosis and management of coronary artery disease. This article highlights major historic perspectives, the accuracy of coronary computed tomography angiography in evaluating obstructive coronary artery disease, associated radiation exposure issues, considerations in patient selection, and ongoing clinical and technologic advancements.

Effect of a novel vendor-specific motion-correction algorithm on image quality and diagnostic accuracy in persons undergoing coronary CT angiography without rate-control medications.

BACKGROUND: Although coronary CT angiography (CTA) shows high diagnostic performance for detection and exclusion of obstructive coronary artery disease, limited temporal resolution of current-generation CT scanners may allow for motion artifacts, which may result in nonevaluable coronary segments. OBJECTIVE: We assessed a novel vendor-specific motion-correction algorithm for its effect on image quality and diagnostic accuracy. METHODS: Thirty-six consecutive patients with severe aortic stenosis undergoing coronary CTA without rate control and invasive coronary angiography as part of an evaluation for transcatheter aortic valve replacement. We compared image quality and diagnostic accuracy between standard (STD) and motion-corrected (MC) reconstructions. Coronary CTAs were interpreted in an intent-to-diagnose fashion by 2 experienced readers; a third reader provided consensus for interpretability and obstructive coronary stenosis (≥50% stenosis). All studies were interpreted with and without motion correction using both 45% and 75% of the R-R interval for reconstructions. Quantitative coronary angiography was performed by a core laboratory. RESULTS: Mean age was 83.0 ± 6.4 years; 47% were men. Overall image quality (graded 1-4) was higher with the use of MC versus STD reconstructions (2.9 ± 0.9 vs 2.4 ± 1.0; P < 0.001). MC reconstructions showed higher interpretability on a per-segment [97% (392/406) vs 88% (357/406); P < 0.001] and per-artery [96% (128/134) vs 84% (112/134); P = 0.002] basis, with no difference on a per-patient level [92% (33/36) vs 89% (32/36); P = 1.0]. Diagnostic accuracy by MC reconstruction was higher than STD reconstruction on a per-segment [91% (370/406) vs 78% (317/406); P < 0.001] and per-artery level [86% (115/134) vs 72% (96/134); P = 0.007] basis, with no significant difference on a per-patient level [86% (31/36) vs 69% (25/36); P = 0.16]. CONCLUSIONS: The use of a novel MC algorithm improves image quality, interpretability, and diagnostic accuracy in persons undergoing coronary CTA without rate-control medications.

MDCT to guide transcatheter aortic valve replacement and mitral valve repair.

Percutaneous management of valvular heart disease is becoming a reality, with multicenter trials supporting minimally invasive procedures for both aortic and mitral valve disease. Historically, the treatment of choice has been aortic valve replacement with conventional surgery for patients with severe aortic stenosis, as the prognosis of untreated patients is poor, particularly if the patient is symptomatic. Transcatheter aortic valve replacement is now available as a minimally invasive option to treat select high-risk patients with severe aortic stenosis. At present more than 30,000 procedures have been performed worldwide, mostly confined to patients at high surgical risk. The short- and medium-term outcomes have been promising.

Thoracic computed tomographic manifestations of tuberous sclerosis in adults.

The purpose of this article is to illustrate the various manifestations that can be encountered on thoracic computed tomography of tuberous sclerosis in adults. The pulmonary findings include lymphangioleiomyomatosis and multifocal micronodular pneumocyte hyperplasia. The extrapulmonary manifestations are divided into cardiac, vascular, mediastinal, osseous, and upper abdominal findings.

Confirmed swine-origin influenza A(H1N1) viral pneumonia: computed tomographic findings in the immunocompetent and the immunocompromised.

AIM: This study aimed to retrospectively evaluate the computed tomographic (CT) appearance of cases of swine-origin influenza A(H1N1) viral infection (S-OIV) in immunocompetent and immunocompromised patients confirmed with reverse transcription-polymerase chain reaction and to determine whether the timing of CT relative to the onset of symptoms affected the overall imaging appearance [corrected]. METHODS: A total of 23 patients (15 men and 8 women) from 2 tertiary care centers formed the final study population. Patients were divided into 2 groups based on their immune status: group 1 (n = 14) were patients who were immunocompromised, whereas group 2 (n = 9) were patients who were immunocompetent. The radiologic appearances of pulmonary abnormalities, distribution, and extent of involvement on the initial chest CT scan were documented, and correlation with the onset of symptoms was performed. RESULTS: The most common CT pattern in both groups of S-OIV patients was ground-glass opacities and consolidation (group 1, 86%; group 2, 71%) in a bilateral, subpleural, and peribronchovascular pattern. Small airways disease [corrected] was seen only in a minority of patients (group 1, 7%; group 2, 11%. Onset of symptoms to time of CT showed a mean duration of 9.7 days in group 1 and 6.7 days in group 2 and did not affect the overall imaging appearance. CONCLUSIONS: The most common abnormalities on CT scans of both immunocompetent and immunocompromised S-OIV patients were ground-glass opacities and consolidation in a bilateral, subpleural, and peribronchovascular distribution, resembling organizing pneumonia. This appearance was seen regardless of the timing of CT relative to the onset of symptoms.