Multidetector Row CT Scanner Research Articles

Automatic detection of pulmonary nodules: Evaluation of performance using two different MDCT scanners

The purpose of this study was to evaluate the diagnostic performance of a computer-aided diagnosis (CAD) system, on the detection of pulmonary nodules in multidetector row computed tomography (MDCT) images, by using two different MDCT scanners. The computerized scheme was based on the iris filter. We have collected CT cases of patients with pulmonary nodules. We have included in the study one hundred and thirty-two calcified and noncalcified nodules, measuring 4-30 mm in diameter. CT examinations were performed by using two different equipments: a CT scanner (SOMATOM Emotion 6), and a dual-source computed tomography system (SOMATOM Definition) (Siemens Medical System, Forchheim, Germany), with the following parameters: collimation, 6x1.0mm (Emotion 6); and 64×0.6mm (Definition); 100-130 kV; 70-110 mAs. Data were reconstructed with a slice thickness of 1.25mm (Emotion 6) and 1mm (Definition). True positive cases were determined by an independent interpretation of the study by three experienced chest radiologists, the panel decision being used as the reference standard. Free-response Receiver Operating Characteristic curves, sensitivity and number of false-positive per scan, were calculated. Our CAD scheme, for the test set of the study, yielded a sensitivity of 80%, with an average of 5.2 FPs per examination. At an average false positive rate of 9 per scan, our CAD scheme achieved sensitivities of 94% for all nodules, 94.5% for solid, 80% for non-solid, 84% for spiculated, and 97% for non-spiculated nodules. These encouraging results suggest that our CAD system, advocated as a second reader, may help radiologists in the detection of lung nodules in MDCT.

Incidental occult gunshot wound detected by postmortem computed tomography

The body of a 59year old woman underwent postmortem computed tomography (PMCT) examination prior to forensic autopsy, using a 256 slice multidetector row computed tomography scanner. A large left tension pneumothorax detected on the PMCT was considered to be a likely cause of death and this was confirmed at autopsy. In addition there was an unsuspected PMCT finding of a probable gunshot injury traversing the right orbit, facial bones and frontal sinus. The autopsy technique was adjusted accordingly and PMCT findings confirmed. PMCT in this case was not only diagnostic of cause of death, but also revealed retained projectile fragments of an old gunshot wound to the face. Without prior imaging such findings would have been undetected at autopsy. This case further underscores the contribution of routine PMCT examination to forensic autopsy practice.

Radiation dose reduction from low-kilovoltage liver computed tomography using multidetector rowcomputed tomography

The primary goal of this study was to ascertain the reduction in radiation dose when conducting low-kilovoltage liver computed tomography (CT) examinations using multidetector row CT (MDCT). Fifty patients under follow-up who were diagnosed with liver cancer were examined using a 16-slice MDCT scanner and volume CT dose index (CTDI(vol)) measured according to the methods of examination, which were based on a three-phase CT scan conducted in the previous year and a four-phase CT scan was done a year later. Scanning parameters were 120 kVp-140 mA s, 120 kVp-120 mA s and 80 kVp-280 mA s. The CTDI(vol) was decreased to ∼47% at 80 kVp -280 mA s. The results indicate that low-kilovoltage liver CT is a useful means of reducing radiation doses.

Radiation Dose Reduction in Abdominal Computed Tomography During the Late Hepatic Arterial Phase Using a Model-Based Iterative Reconstruction Algorithm

The aim of this study was to compare the image quality of abdominal computed tomography scans in an anthropomorphic phantom acquired at different radiation dose levels where each raw data set is reconstructed with both a standard convolution filtered back projection (FBP) and a full model-based iterative reconstruction (MBIR) algorithm. An anthropomorphic phantom in 3 sizes was used with a custom-built liver insert simulating late hepatic arterial enhancement and containing hypervascular liver lesions of various sizes. Imaging was performed on a 64-section multidetector-row computed tomography scanner (Discovery CT750 HD; GE Healthcare, Waukesha, WI) at 3 different tube voltages for each patient size and 5 incrementally decreasing tube current-time products for each tube voltage. Quantitative analysis consisted of contrast-to-noise ratio calculations and image noise assessment. Qualitative image analysis was performed by 3 independent radiologists rating subjective image quality and lesion conspicuity. Contrast-to-noise ratio was significantly higher and mean image noise was significantly lower on MBIR images than on FBP images in all patient sizes, at all tube voltage settings, and all radiation dose levels (P < 0.05). Overall image quality and lesion conspicuity were rated higher for MBIR images compared with FBP images at all radiation dose levels. Image quality and lesion conspicuity on 25% to 50% dose MBIR images were rated equal to full-dose FBP images. This phantom study suggests that depending on patient size, clinically acceptable image quality of the liver in the late hepatic arterial phase can be achieved with MBIR at approximately 50% lower radiation dose compared with FBP.

Perfusion CT cerebral blood volume and permeability surface in low and high grades of brain glioma

PurposeTo study if glioma grade could be correlated with perfusion CT parameters; permeability surface (PS) and cerebral blood volume (CBV) and if high-grade glioma would show different parameter levels as compared with low-grade glioma. Patients and methodsPerfusion CT (PCT) was conducted for 40 patients with untreated glioma using 64 multidetector-row CT scanner. Perfusion maps of PS and CBV were generated, and these parameters were measured. World Health Organization (WHO) glioma grades were compared with PCT parameters. ResultsThe 40 patients were classified as low-grade glioma group (18 patients) and high-grade glioma group (22patients). There was highly significant difference (P<0.001) between the two groups as regard the mean values of CBV& PS in tumor sides where they were higher in the high-grade glioma group. Receiver operating characteristic (ROC) analyses showed that PS (AUC 0.818) is better than CBV (AUC 0.788) in differentiating low- and high-grade glioma and so PS had higher predictability than CBV regarding glioma grading. ConclusionChanges in PS and CBV values had good correlation with glioma grading; with PS was the best parameter correlating with glioma grade. High grade glioma showed higher PS and CBV levels as compared with low-grade glioma.

A Rare Differential Diagnosis for Cause of Proptosis: Skull Plasmacytoma

True solitary plasmacytoma of the skull without signs of systemic myelomatosis is very rare as is orbital involvement. It can be part of generalized disease (multiple myeloma) or localized disease, presenting as orbital tumor. We describe a case of solitary osseous plasmacytoma of the orbit. This 40-year-old man presented with a four month history of proptosis of the left eye, swelling in the left orbito-temporal region with a mild decrease in visual acuity. Multidetector row computed tomography scan showed a geographic osteolytic, well-demarcated lesion involving the greater wing of the sphenoid bone showing homogeneous contrast enhancement with extra-axial extension to the middle and anterior cranial fossa extension with extraconal extension into the orbit at the right side. Fine needle and later biopsy of the lesion revealed plasmacytoma.

WE‐A‐218‐02: Assessing the Repair of DNA Damage from Multi‐Pass CT Protocols

Purpose: To determine whether radiation damage is additive for fractionated doses at diagnostic levels using mouse tumor infiltrating lymphocytes (Til) in an in vitro assay. Methods: Til cells placed in the center chamber of a CDTI head phantom were irradiated using a Multidetector row CT scanner (Siemens Sensation64). 20mGy, 40mGy or 60mGy (reported CTDIvol values) irradiations were performed by either a single pass or multiple passes of 20mGy separated by 2 minutes. The cellular response to DNA double strand breaks (DSBs) was quantified by flow cytometric quantitation of gammaH2AX foci 1hr post‐irradiation at room temperature. Non‐irradiated controls were included for each sample. Collected flow cytometry data, corrected for debris and dead cells using side and forward scatter gating, were analyzed with CellQuest Pro Software. Fluorescence histograms were generated and median fluorescence of each treatment sample was compared to respective controls and excess gammaH2AX signal was reported. Results represent the average from three independent experiments. Results: A linear, dose‐dependent response of excess gammaH2AX signal was observed for single pass doses of 20– 60mGy. However, in cells exposed to multiple passes of 20mGy, a significant decrease (P&lt;0.05) in excess gammaH2AX signal was observed compared to equivalent single pass doses. Conclusion: These preliminary results suggest multi‐pass CT protocols may alter the biological response to DNA DSBs in vitro, with significantly reduced gammaH2AX signal when the same total dose is fractionated, even with very short inter‐fraction intervals (minutes), rather than delivered as a single exposure. Kinetic analysis is necessary to determine whether this reduction is due to increased repair rate or decreased repair capacity. This altered response could have marked implications for current diagnostic procedures and thus underscore the importance of understanding how imaging protocols may affect the biological response in order to accurately assess risk estimates and biological dose. This work is partially supported by a SIEMENS Corporation research grant.

Interactive GPU-based maximum intensity projection of large medical data sets using visibility culling based on the initial occluder and the visible block classification

Maximum intensity projection (MIP) is an important visualization method that has been widely used for the diagnosis of enhanced vessels or bones by rotating or zooming MIP images. With the rapid spread of multidetector-row computed tomography (MDCT) scanners, MDCT scans of a patient generate a large data set. However, previous acceleration methods for MIP rendering of such a data set failed to generate MIP images at interactive rates. In this paper, we propose novel culling methods in both object and image space for interactive MIP rendering of large medical data sets. In object space, for the visibility test of a block, we propose the initial occluder resulting from a preceding image to utilize temporal coherence and increase the block culling ratio a lot. In addition, we propose the hole filling method using the mesh generation and rendering to improve the culling performance during the generation of the initial occluder. In image space, we find out that there is a trade-off between the block culling ratio in object space and the culling efficiency in image space. In this paper, we classify the visible blocks into two types by their visibility. And we propose a balanced culling method by applying a different culling algorithm in image space for each type to utilize the trade-off and improve the rendering speed. Experimental results on twenty CT data sets showed that our method achieved 3.85 times speed up in average without any loss of image quality comparing with conventional bricking method. Using our visibility culling method, we achieved interactive GPU-based MIP rendering of large medical data sets.

Carotid Artery Plaque Classification: Does Contrast Enhancement Play a Significant Role?

Previous articles have demonstrated that carotid artery plaques may have enhancement after administration of contrast material. The purpose of this study was to evaluate the effect of enhancement in carotid artery classification. Three hundred eighty consecutive patients (235 men, 145 women; median age 64, age range 32-87 years) were analyzed using a multidetector row CT scanner. Examinations were performed before and after CM administration. Carotid artery plaques with a attenuation value <60 HU were considered fatty, those from 60-130 HU were considered mixed, and those >130 HU were considered calcified. χ(2) tests, Student t tests, and Cohen analyses were performed. Before CM administration, we observed 226 calcified, 175 mixed, and 206 fatty plaques; after CM administration, 229 calcified, 213 mixed, and 165 fatty plaques were observed. A statistically significant difference between these 2 groups was observed (P = .016). We found that 19.9% of fatty plaques become mixed (n = 41), whereas 1.7% of the mixed plaques become calcified (n = 3). All calcified plaques remained in the same category. Fatty plaques that changed type showed a larger enhancement compared with those that remained in the same class (P = .001). Cohen analyses showed very good agreement between observers before (κ = 0.834) and after contrast material administration (κ = 0.86). The results of this study indicate that the carotid artery plaques (fatty and mixed) significantly change according to whether analysis is performed before or after administration of contrast material.

Presurgical planning for arteriovenous malformations using multidetector row CT

Microsurgical resection remains an important treatment for cerebral arteriovenous malformations (AVMs). We developed an accurate method for planning AVM resections using multidetector row CT (MDCT). Between January 2007 and January 2011, 21 consecutive patients with AVMs were enrolled in this study. Sixteen patients were symptomatic, and of these, 15 had a hemorrhagic onset. Preoperative CT angiography (CTA) was performed using an MDCT scanner (GE Lightspeed VCT; GE Healthcare, Milwaukee, WI, USA). In total, 1 to 1.2mL/kg of iopamidol, a low-osmolar iodinated contrast material, was administered intravenously with the bolus tracking method. In all cases, three-dimensional CTA imaging demonstrated critical arterial feeders and their specific geometric associations with the nidus. Accurate visualization of the architecture of AVMs and surgical trajectory was possible with the volume rendering method, especially when using transparency imaging. Additionally, employing feeder extraction imaging with segmentation post-processing, clear preoperative identification of the feeding arteries around the surrounding structures allowed for not only intraoperative orientation but also planning for presurgical embolization. Moreover, the precise anatomical structures of the brain surface were obtained using fusion imaging with MRI. While it is difficult to scientifically assign a value to a technology, we sought to objectively assess the utility of the currently available CTA. The significant benefits of this modality for presurgical planning include enhanced surgeon confidence and optimization of the sequence of surgical procedures.

Loss of cellular viability in areas of ground-glass opacity on computed tomography images immediately after pulmonary radiofrequency ablation in rabbits

To determine cellular viability of lung parenchyma and neoplastic cells in areas of ground-glass opacity (GGO) on computed tomography (CT) images immediately after pulmonary radiofrequency ablation (RFA) in rabbits. A LeVeen RFA electrode was placed percutaneously into rabbit lungs with or without metastatic VX2 tumors. Five minutes later, seven isolated lungs were imaged by use of a multi-detector row CT scanner, and the images were compared with histological features. The cellular viability of the lung tissues was assessed by nicotinamide adenine dinucleotide hydrogen (NADH) staining in eight normal lungs and in three lungs with multiple metastatic tumors. All lung lesions appeared as bilayered structures with a central, dense, attenuated area and an outer area of GGO on CT images, and as three-layered structures on macroscopic and microscopic images 5 min after RFA. The GGO areas approximately corresponded to the outer two layers in macroscopic images that were exudative and congestive on microscopic images. Staining for NADH was significantly reduced in the GGO and densely attenuated areas with or without tumor tissue staining compared with the non-ablated area. Our results suggest that an area of GGO that appears on CT immediately after RFA can be effectively treated by RFA.

Triaging patients with acute chest pain in the emergency department: implications of the CT-STAT trial

Evaluation of: Goldstein JA, Chinnaiyan KM, Abidov A et al. The CT-STAT (Coronary Computed Tomographic Angiography for Systematic Triage of Acute Chest Pain Patients to Treatment) trial. J. Am. Coll. Cardiol. 58(14), 1414–1422 (2011).Rapid advancements in multidetector-row computed tomography scanner technology over the last decade have significantly improved the diagnostic performance of coronary computed tomography angiography (CTA), enabling it to potentially become the preferred imaging modality used in the rapid assessment of chest pain patients in the emergency department. There is a growing body of evidence suggesting coronary CTA can rule out coronary artery stenosis quickly and accurately, thereby reducing the number of hospitalizations and healthcare costs, without compromising quality of care. CT-STAT is the first multicenter trial to demonstrate the power of coronary CTA to streamline patient care in the acute setting and radically transform current treatment algorithms.

Automated pelvic anatomical coordinate system is reproducible for determination of anterior pelvic plane

Most of computer-assisted planning systems need to determine the anatomical axis based on the anterior pelvic plane (APP). We analysed that our new system is more reproducible for determination of APP than previous methods. A pelvic model bone and two subjects suffering from hip osteoarthritis were evaluated. Multidetector-row computed tomography (MDCT) images were scanned with various rotations by MDCT scanner. The pelvic rotation was calibrated using silhouette images. APP was determined by an optimisation technique. The values of variation of APP caused by pelvic rotation were analysed with statistical analysis. APP determination with calibration and optimisation was most reproducible.The values of variance of APP were within 0.05° in model bone and 0.2° even in patient pelvis. Furthermore, the values of variance of APP with calibration/optimisation were significantly lower in comparison without calibration/optimisation. Both calibration and optimisation are actually required for determination of APP. This system could contribute to the evaluation of hip joint kinematics and computer-assisted surgery.

Noncontrast multidetector-row computed tomography scanning for detection of radiolucent calculi in acute renal insufficiency caused by bilateral ureteral obstruction of ceftriaxone crystals

Noncontrast computed tomography (CT) has great advantage with higher sensitivity and more clear modalities in detecting urinary tract radiolucent calculi in patients with acute renal insufficiency (ARI) compared to other image diagnosis approaches. We report two cases (female, 28 years old; male, 39 years old) with persistent flank pain and acute anuria after the administration of ceftriaxone (4.0 g daily) for 2 days intravenously. No abnormality was found in the kidney-ureter- bladder (KUB) areas with plain abdomen X-rays. A diagnosis of bilateral hydronephrosis was made by ultrasound examination in both cases. Serum creatinine levels reached up to 257 and 810 μ mol/L (normal serum creatinine level is 40-130 μ mol/L), respectively. Vague density spots were noticed in the pelvis with noncontrast multidetector-row CT (MDCT) scanning. However, distinguishable clusters of high-density shadows were seen in pelvic areas with maximum intensity projections (MIP, CT values in 30-128 HU). Ceftriaxone crystal calculi were found on both sides of distal ureters under endoscopy. Renal function recovered in both patients after double-J ureteral stents were installed. Out results demonstrated that noncontrast MDCT scanning and MIP reconstruction as an effective diagnostic tool could provide clear images in detection of radiolucent calculi in urinary tract when conventional X-rays image are not suitable in the patients with obstructive anuria and ARI of unknown origin.

Radiation dose reduction with application of non-linear adaptive filters for abdominal CT

To evaluate the effect of non-linear adaptive filters (NLAF) on abdominal computed tomography (CT) images acquired at different radiation dose levels. Nineteen patients (mean age 61.6 ± 7.9 years, M:F = 8:11) gave informed consent for an Institutional Review Board approved prospective study involving acquisition of 4 additional image series (200, 150, 100, 50 mAs and 120 kVp) on a 64 slice multidetector row CT scanner over an identical 10 cm length in the abdomen. The CT images acquired at 150, 100 and 50 mAs were processed with the NLAF. Two radiologists reviewed unprocessed and processed images for image quality in a blinded randomized manner. CT dose index volume, dose length product, patient weight, transverse diameters, objective noise and CT numbers were recorded. Data were analyzed using Analysis of Variance and Wilcoxon signed rank test. Of the 31 lesions detected in abdominal CT images, 28 lesions were less than 1 cm in size. Subjective image noise was graded as unacceptable in unprocessed images at 50 and 100 mAs, and in NLAF processed images at 50 mAs only. In NLAF processed images, objective image noise was decreased by 21% (14.4 ± 4/18.2 ± 4.9) at 150 mAs, 28.3% (15.7 ± 5.6/21.9 ± 4) at 100 mAs and by 39.4% (18.8 ± 9/30.4 ± 9.2) at 50 mAs compared to unprocessed images acquired at respective radiation dose levels. At 100 mAs the visibility of smaller structures improved from suboptimal in unprocessed images to excellent in NLAF processed images, whereas diagnostic confidence was respectively improved from probably confident to fully confident. NLAF lowers image noise, improves the visibility of small structures and maintains lesion conspicuity at down to 100 mAs for abdominal CT.

Computed tomography liver volumetry using 3-dimensional image data in living donor liver transplantation: Effects of the slice thickness on the volume calculation

The purpose of this study was to evaluate the relationship between the slice thickness and the calculated volume in computed tomography (CT) liver volumetry through the comparison of the results from images [including 3-dimensional (3D) images] with various slice thicknesses. Twenty potential adult liver donors (12 men and 8 women) with a mean age of 39 years (range = 24-64 years) underwent CT with a 64-section multidetector row CT scanner after the intravenous injection of a contrast material. Four image sets with slice thicknesses of 0.625, 2.5, 5, and 10 mm were used. First, a program developed in our laboratory for automated liver extraction was applied to the CT images, and the liver boundaries were determined automatically. Then, an abdominal radiologist reviewed all images onto which automatically extracted boundaries had been superimposed and then edited the boundaries on each slice to enhance the accuracy. The liver volumes were determined via the counting of the voxels within the liver boundaries. The mean whole liver volumes estimated with CT were 1322.5 cm(3) from 0.625-mm images, 1313.3 cm(3) from 2.5-mm images, 1310.3 cm(3) from 5-mm images, and 1268.2 cm(3) from 10-mm images. The volumes calculated from 3D (0.625-mm) images were significantly larger than the volumes calculated from thicker images (P < 0.001). The partial liver volumes of right lobes, left lobes, and lateral segments were evaluated in a similar manner. The estimated maximum difference in the calculated volumes of lateral segments was -10.9 cm(3) (-4.63%) between 0.625- and 5-mm images. In conclusion, liver volumes calculated from 2.5-mm-thick or thicker images are significantly smaller than liver volumes calculated from 3D images. If a maximum error of 5% in the calculated graft volume will not have a significant clinical impact, 5-mm-thick images are acceptable for CT volumetry. If the impact is significant, 3D images could be essential.

Cause of apical thinning on attenuation-corrected myocardial perfusion SPECT

Decreases in apical and apex activities - namely, 'apical thinning' - are a well-known phenomenon in attenuation-corrected (AC) myocardial perfusion. The aim of this study was to compare actual myocardial thickness derived from a multidetector-row computed tomography with AC myocardial perfusion count from a hybrid single-photon emission computed tomography/computed tomography to investigate the cause of apical thinning. We enrolled 21 participants with a low likelihood of coronary artery disease (mean age 65 ± 21 years, 13 men) from 185 consecutive patients and 11 healthy volunteers, who independently underwent ⁹⁹mTc-sestamibi single-photon emission computed tomography/computed tomography and 64-slice multidetector-row computed tomography scans. AC and non-AC myocardial perfusion counts and thickness were measured on the basis of a 17-segment model and averaged at the apex, apical, mid, and basal walls. Myocardial thickness at the apex was significantly thinner than that at the apical and mid walls (5.1 ± 1.3, 7.3 ± 1.3, and 9.9 ± 2.4 mm, respectively; P<0.005). AC count at the apex was significantly lower than that at the apical and mid regions (76.0 ± 5.5, 82.8 ± 4.7, and 85.6 ± 3.8, respectively; P<0.002). Moderate relationship was observed between myocardial thickness and AC count (y=-10.5 + 0.22x, r=0.54, P<0.0001. No relationship was found between thickness and non-AC count (r=0.16, P=0.263). The low apex and apical counts were caused by anatomical thinning of the myocardium in AC myocardial perfusion imaging. Attenuation correction provided an accurate relationship between myocardial count and thickness because of the partial volume effect.

Evaluation of Hepatocellular Carcinoma Size Using Two-dimensional and Volumetric Analysis: Effect on Liver Transplantation Eligibility

Milan criteria recommends selection of candidates with hepatocellular carcinoma (HCC) for liver transplantation based on strict tumor size thresholds. The purpose of this study is to compare the effect of two-dimensional and three-dimensional tumor measurements on the selection of candidates for liver transplantation using Milan criteria. This retrospective Health Insurance Portability and Accountability Act-compliant study was approved by our institutional review board. Patient-informed consent was waived. Forty-five HCCs in 19 patients, evaluated with triphasic multidetector row computed tomography scans, were included in the analysis. The largest diameters in each two-dimensional orthogonal plane (Max2D) and within three-dimensional tumor boundaries (Max3D) were calculated for each lesion. Diameters were compared and the eligibility based on lesion size for liver transplantation was assessed. The mean Max2D diameter of HCC was 3.2 ± 0.9 cm and the mean Max3D diameter was 3.5 ± 1.2 cm. There was a significant difference between the mean Max2D and Max3D diameters (P < .001). Among the 45 lesions, 22 of them (48.9%) were ineligible for transplantation according to Max2D diameter, whereas 29 of them (64.44%) were ineligible when Max3D diameter was applied (P < .001). HCC diameter based on 3D measurements is significantly different than the conventional 2D measurements and may affect eligibility for liver transplantation.

Correlation Between Pixel Values in a Cone-Beam Computed Tomographic Scanner and the Computed Tomographic Values in a Multidetector Row Computed Tomographic Scanner

The study's objectives were to investigate the correlation between pixel values obtained from a cone-beam computed tomographic (CBCT) scanner and the computed tomographic (CT) values from a multidetector row CT scanner and to determine whether they have a linear relationship at various tube voltages and tube currents. A phantom with different concentrations of contrast medium at the center of a multidetector row CT and a CBCT scanner was scanned at various imaging parameters. Computed tomographic values and pixel values were measured using ImageJ. Regression analysis was performed, as well as correlation tests with a Pearson correlation coefficient. A significant correlation between pixel values and the CT values of the same specimen was observed (P < 0.0001), and a linear relationship was found between the values from the 2 scanners at each parameter. A high correlation and linear relationship between the CT values and pixel values were found at each parameter. Therefore, linear functions can be used to convert a pixel value from the CBCT machine used in this study to the CT values.

Bronchial Diverticula Detected by Multidetector-Row Computed Tomography

Our aim was to investigate the incidence and characteristics of bronchial diverticula using multidetector-row computed tomography (MDCT) and to evaluate their association with smoking status. Two radiologists retrospectively reviewed MDCT scans obtained between December 2007 and February 2008 with a 4-row or a 64-row MDCT scanner for 1122 consecutive patients. Bronchial diverticula were assessed for incidence, locations, and sizes. Smoking history, including the Brinkman Index, was recorded from clinical records. Statistical analysis used χ or t tests to evaluate associations between patients' clinical information (age, sex, or smoking history) and the presence of bronchial diverticula. A total of 401 bronchial diverticula were found in 242 (21.6%) patients (mean, 1.65; mode, 1 per patient). Most diverticula were 1 or 2 mm in size. Bronchial diverticula were most frequently detected in the subcarinal region. Of these 242 patients with diverticula, 142 (58.7%) were male and had a higher prevalence than women (P<0.01). No significant difference in age was found between the groups with and without bronchial diverticula. Although bronchial diverticula were also observed in lifelong nonsmokers, the group with bronchial diverticula had a higher percentage of smokers than the group without bronchial diverticula (P=0.01). The Brinkman Index for the group with bronchial diverticula was significantly higher than for the group without diverticula (P<0.01). Bronchial diverticula are frequently observed on chest MDCT scans and are associated with cigarette smoking.