Optimal imaging protocol for measuring dynamic expiratory collapse of the central airways.

AIM: To compare measurements of expiratory collapse obtained using multidetector computed tomography (MDCT) of the central airways on routine axial and multiplanar reformatted (MPR) images. MATERIALS AND METHODS: Fifty volunteers with normal pulmonary function and no smoking history were imaged using a 64 MDCT system (40 mAs, 120 kVp, 0.625 mm collimation) with spirometric monitoring at end-inspiration and during forced expiration. Measurements of the trachea, right main (RMB) and left main bronchus (LMB) were obtained on axial and MPR images. Inspiratory and dynamic-expiratory cross-sectional area (CSA) measurements were used to calculate the mean percentage expiratory collapse (%Collapse). A paired t-test was used to assess within-subject differences and a Bland-Altman plot was used to assess agreement between the methods. RESULTS: Among 24 men and 26 women (mean age±standard deviation 50±15 years), CSA values were significantly greater on axial than MPR images (all p<0.001); however, the mean difference in %Collapse values for axial versus MPR were small: trachea ≈1% (55 ±19 versus 56±18, p=0.338); LMB identical (60±20 versus 60±17 p=0.856); and, RMB 4% (62 ±19 versus 66±19 p<0.001). On average, creation of MPR required 12 minutes of additional time per case (range=10-15 min). CONCLUSION: Differences in mean %Collapse for axial versus MPR images were small and unlikely to influence clinical management. This finding suggests that MPR may not be indicated for routine assessment of central airway collapse.

Subcarinal collection following mediastinoscopy: a normal post-procedural CT finding.

AIM: To determine the frequency with which a subcarinal collection is present at computed tomography (CT) following mediastinoscopy and to determine the CT features of the collection. MATERIALS AND METHODS: All patients who underwent uncomplicated mediastinoscopy during a 1-year period were retrospectively identified. This list was cross-referenced to determine those patients who also underwent CT within 15 days after the procedure. Each post-mediastinoscopy CT examination was assessed in consensus by three fellowship-trained thoracic radiologists for the presence of subcarinal abnormalities, which were also characterized in terms of their size and density. Additional CT findings were recorded, including tracheobronchial wall thickening, paratracheal collections, mediastinal fat stranding, and mediastinal air. RESULTS: The study cohort included 10 patients (seven men and three women) with mean age of 65 years (range 49-81 years). CT was performed a mean of 11 days following mediastinoscopy. The most common CT finding was an oval subcarinal collection in nine of 10 cases (size 1.1-3.2 cm). In all nine cases, the subcarinal collections were consistently lower in attenuation than the subcarinal lymph node in the same region on the pre-procedure CT examination. Other CT findings included anterior tracheobronchial wall thickening (n=7); paratracheal collection (n=6); mediastinal fat stranding (n=6); and mediastinal air in (n=4) cases. CONCLUSION: A subcarinal collection was identified in 90% of cases following mediastinoscopy. Its rapid development and characteristic appearance help to distinguish it from a lymph node.

Prospective study of digital radiographs versus conventional screen films in Small Bowel Follow-Through examination.

PURPOSE: To prospectively compare subjective radiological quality, radiation dose and effect on workflow using digital radiography (DR) vs. conventional screen film (SF) radiography in the Small Bowel Follow-Through (SBFT) examination. METHODS: Five attending and four resident radiologists compared hard-copy images from 11 SBFT examinations, for which every patient had a defined pair of SF and DR images taken 20-30 min apart. SF and DR were performed with equivalent exposure data. Overall image quality, intestinal mucosa definition and bone visualization were graded on a 5-point scale, with 5 being the highest value. Thus, 11 patients had three criteria judged by nine observers in two modalities for a total of 594 observations of image quality. The radiation doses and effect on workflow were also compared. Statistical analysis was performed with the Mann-Whitney U test. RESULTS: The mean scores on DR and SF for overall image quality, intestinal mucosa definition and bone visualization were 4.49 vs. 3.17, 4.38 vs. 3.4, and 4.5 vs. 2.4, respectively (p<0.001 in all cases). The average radiation dose with DR was 0.93+/-0.54 cGy, and -1.58+/-0.63 cGy with SF (p=0.016), reflecting a 41% dose reduction. Production of a DR image by technicians took 3.5+/-1.3 min vs. 5.5+/-1.5 min for SF (p=0.002). CONCLUSION: Subjective image quality of hard-copy digital radiographs of the small bowel through examination is superior to images obtained with conventional radiographs, with an associated reduction of 41% in radiation dose and increased efficiency.

Elongated eccentric soft coronary plaque: major diagnostic pitfall on quantitative coronary angiography overpowered by computed tomography coronary angiography and intravascular ultrasound.

We describe a significant left anterior descending coronary lesion in a patient with unstable angina pectoris. This lesion was erroneously underestimated using quantitative coronary angiography; however, CT coronary angiography correctly showed a significant, elongated, eccentric, soft plaque that was later confirmed by repeated quantitative coronary angiography with intravascular ultrasound. As showed, CT coronary angiography may offer a reliable non-invasive alternative to quantitative coronary angiography and intravascular ultrasound by enabling a true 3-D coronary lumenogram combined with plaque detection and characterization.

Comprehensive multidetector CT assessment of apical hypertrophic cardiomyopathy.

16-slice multidetector CT (MDCT) cardiac findings of a middle-aged man with known apical hypertrophic cardiomyopathy (AHC) and recent atypical chest pain are presented. MDCT enabled comprehensive evaluation of the coronary arteries, diagnosing myocardial bridging of the left anterior descending (LAD) and first diagonal arteries. It also enabled dynamic evaluation of myocardial thickness and left ventricular global and regional function. This case illustrates the full capabilities of MDCT in the evaluation of AHC.

Incidence of familial Mediterranean fever (FMF) mutations among children of Mediterranean extraction with functional abdominal pain.

Of 59 Sephardic Jewish and Arab children in whom functional abdominal pain was diagnosed, we found that 20% were homozygote for the familial Mediterranean fever gene. Inclusion of genetic screening for familial Mediterranean fever may be advisable in the investigation of recurrent abdominal pain among children of Mediterranean extraction.