Multidetector Computed Tomography Imaging Research Articles

Electrocardiography scar quantification correlates with scar size of hypertrophic cardiomyopathy seen by multidetector computed tomography.

Hypertrophic cardiomyopathy (HCM), a genetically transmitted disease, is the most common genetic cardiovascular disease. Current strategies to stratify risk are expensive and concentrated in wealthy centers. Twelve-lead electrocardiography (ECG) is inexpensive, universally available, and can be readily used for Selvester QRS scoring, which estimates scar size. This study aimed to establish the relation between ECG scar quantification and myocardial fibrosis (extent of myocardial delayed enhancement) in multidetector computed tomography (MDCT). There is a significant association between ECG scar quantification and the extent of myocardial delayed enhancement in MDCT. Seventy-five patients with HCM underwent a routine clinical evaluation and echocardiography, 12-lead ECG, and MDCT study. Patients with and without an implantable cardioverter-defibrillator were included. The estimated Selvester QRS score of myocardial fibrosis was correlated significantly (R = 0.70; P < 0.01) with the quantified MDCT fibrosis. Compared with MDCT, the QRS score had 84.8% sensitivity and 88.8% specificity. Myocardial fibrosis was present in 88% of these patients with HCM (fibrotic mass, 9.87 ±10.8 g) comprising 5.66% ±6.16% of the total myocardial mass seen on the MDCT images. The Selvester QRS score reliably predicted the fibrotic mass in 76% of patients, which estimated 8.44% ±7.39% of the total myocardial mass. The Selvester QRS score provides reliable quantification of myocardial fibrosis and was well correlated with MDCT in patients with HCM.

Reevaluation of Mandibular Morphometry According to Age, Gender, and Side.

This study aims to reevaluation the linear and angular measurements of mandibles with multidetector computed tomography (MDCT) that is a new method and used frequently in recent years. The archived MDCT images of 100 adult patients (age range, 15-74 years) without mandibular operation and trauma history were evaluated retrospectively. Mandibular ramus heights, maximal mandibular length, mandibular symphysis height, mandibular angles, and mandibular foramen distance measurements were performed on MDCT images. All measurement parameters were analyzed by gender, age groups, and sides. Mandibular linear length measurements were higher in males than in females (P < 0.05). Only mandibular symphysis height was statistically significantly different in age groups (P < 0.05). The Angle 1 (gonial angle) was found to be significantly higher in females (P < 0.05). The Angle 3 (right condyle-gnathion-left condyle angle) was observed to be significantly higher in the 60+ age group (P < 0.05). The 3 of the mandibular foramen measurements (distance from the front edge, distance to gonion, and height of lingula) were found to be higher in males than in females (P < 0.05). There were no significant differences according to age groups in these measurements. The lengths of the mandibular canals were higher in males (44.72 mm) than in females (41.68 mm). There was no statistically significant difference was found between gender, age groups, and sides of mandibular canal length. The MDCT was found to be a reliable method for the detection of mandibular morphometry when compared with the results of other radiographic images studies.

Multidetector Computed Tomography Imaging: Effect of Sparse Sampling and Iterative Reconstruction on Trabecular Bone Microstructure.

Multidetector computed tomography-based trabecular bone microstructure analysis ensures promising results in fracture risk prediction caused by osteoporosis. Because multidetector computed tomography is associated with high radiation exposure, its clinical routine use is limited. Hence, in this study, we investigated in 11 thoracic midvertebral specimens whether trabecular texture parameters are comparable derived from (1) images reconstructed using statistical iterative reconstruction (SIR) and filtered back projection as criterion standard at different exposures (80, 150, 220, and 500 mAs) and (2) from SIR-based sparse sampling projections (12.5%, 25%, 50%, and 100%) and equivalent exposures as criterion standard. Twenty-four texture features were computed, and those that showed similar values between (1) filtered back projection and SIR at the different exposure levels and (2) sparse sampling and equivalent exposures and reconstructed with SIR were identified. These parameters can be of equal value in determining trabecular bone microstructure with lower radiation exposure using sparse sampling and SIR.

Multi-Detector Computed Tomography Imaging Techniques in Arterial Injuries.

Cross-sectional imaging has become a critical aspect in the evaluation of arterial injuries. In particular, angiography using computed tomography (CT) is the imaging of choice. A variety of techniques and options are available when evaluating for arterial injuries. Techniques involve contrast bolus, various phases of contrast enhancement, multiplanar reconstruction, volume rendering, and maximum intensity projection. After the images are rendered, a variety of features may be seen that diagnose the injury. This article provides a general overview of the techniques, important findings, and pitfalls in cross sectional imaging of arterial imaging, particularly in relation to computed tomography. In addition, the future directions of computed tomography, including a few techniques in the process of development, is also discussed.

Multiplanar Computed Tomography of Vascular Etiologies of Acute Abdomen: A Pictorial Review.

Acute abdomen is a common presentation in the emergency department and radiologic imaging plays a pivotal role in the evaluation of such patients. Multi-detector computed tomography (MDCT) is the most commonly utilized radiologic investigation in such patients as it can be performed fairly rapidly and has excellent accuracy for diagnosing various causes of an acute abdomen. Additionally, MDCT may also reveal clues towards an alternative diagnosis that was not even suspected on the basis of a history and physical examination. Consequently, it is indispensable for radiologists to be able to accurately and efficiently recognize imaging features of disorders that may present as an acute abdomen. While gastrointestinal, hepatobiliary and genitourinary causes account for most cases of acute abdomen, vascular etiologies may also be implicated in a small—but significant—proportion of cases. Therefore, in this pictorial review, we describe the typical MDCT imaging features of various vascular etiologies that may present as an acute abdomen.

Detecting the effect of bisphosphonates during osteoporosis treatment on jawbones using multidetector computed tomography: The OSTEOSYR project.

The aim of the present cross-sectional study was to investigate the effects of bisphosphonates (BP), prescribed for osteoporosis, on jawbones using multidetector computed tomography (MDCT). Fifty-three women who had dual-energy X-ray absorptiometry examination were scanned by MDCT. Both the cortical and the trabecular parts of the alveolar and the cortical bones were compared between BP users and non-BP users using a number of radiological measurements. Linear regression was used for the statistical analysis. The cortical part of the basal bone of the mandible revealed a significant increase in the BP group (.001>P-value≤.026) after using BP for 5years. No alternations were observed in the trabecular part of the basal bone or in the cortical or trabecular parts of the alveolar bone over the same duration. The use of BP as a treatment for osteoporosis for 5years increased the thickness of the cortex of the basal bone of the mandible, as detected by MDCT. The other parts of the jawbones showed no influence by BP for such a purpose, as detected on MDCT images. Accordingly, models (equations) for predicting the alternations in the inferior cortex of the mandible induced by BP therapy during osteoporosis have been suggested.

Multidetector CT Imaging of Bowel and Mesenteric Injury: Review of Key Signs

In contemporary practice, multidetector computed tomography plays a critical role in the diagnostic evaluation of patients with suspected acute mesenteric and bowel trauma. Although less common than solid organ injuries, it may be seen in up to 5% of blunt trauma patients. Evaluation with CT remains challenging even with improvements in technology. The major imaging signs of mesenteric and bowel trauma and what is known about their applicability in clinical practice are reviewed here. Examples illustrate both the subtlety and variable significance of many of the key signs as well as how these are typically integrated into clinical practice.

Differences in clinicopathological characteristics and computed tomography findings between signet ring cell carcinoma and nonsignet ring cell carcinoma in early and advanced gastric cancer.

Signet ring cell carcinoma (SRC) of the stomach is a histological type based on microscopic characteristics. SRC's clinicopathological characteristics and prognosis are still controversial. Our study is to describe the clinicopathological features and multidetector computed tomography (MDCT) findings of patients with SRC of the stomach in comparison with nonsignet ring cell adenocarcinoma (NSRC). We retrospectively analyzed data from 241 patients who had undergone curative gastrectomy, including 62 SRC and 179 NSRC. Clinicopathological outcomes and MDCT findings were evaluated, and we investigated whether these variables were correlated with histopathological type. In early gastric carcinoma, patients with SRC were younger (50.2 vs. 60.2 years; P = 0.000) and more likely to be observed in the middle and lower third stomach (P = 0.010). Early SRC had a tendency to be confined to the mucosa (82.1%). There were significant differences in degree of enhancement between early SRC and NSRC on MDCT imaging (P < 0.001). In advanced gastric carcinoma, SRC was more likely to be stage T3‐4 (100%). SRC patients had thicker tumors (P = 0.001) and a higher frequency of diffusely infiltrative gross appearance (P < 0.001). SRC was more likely to have high‐degree contrast enhancement than were NSRC (P = 0.001). The maximal diameter of SRC tumor on MDCT imaging correlated with lymph node metastasis (sensitivity 93.9%, specificity 74.1%) and serosal invasion (sensitivity 89.5%, specificity 78.0%) of SRC. In conclusion, SRC differs significantly from NSRC in clinicopathological features at presentation. MDCT could help differentiate advanced gastric SRC from NSRC based on the thickened stomach wall, high‐degree contrast enhancement, and a higher frequency of diffusely infiltrative gross appearance, particularly in combination.

Virtual bronchoscopy in differential diagnosis of neoplastic, fibrous and inflammatory abnormalities

The aim of this study was to investigate a role of postprocessing techniques of multidetector computed tomography (CT) and virtual bronchoscopy for differentiation between inflammatory lung lesions and lung tumorous. Methods. Native multidetector CT images of 39 patients with confirmed lung inflammatory lesions and postprocessing reconstruction with virtual bronchoscopy technique were analyzed. 16-slice computed tomograph Toshiba Aquilion 16 and 320-slice computed tomograph Toshiba AquilionONE were used. Results. Focused investigation of bronchial macrostructure in abnormal areas allowed exclusion malignancy and confirmation the inflammatory origin of abnormalities. Conclusion. Virtual bronchoscopy is complementary to native multidetector CT. Key criteria of inflammatory lesions were visualization of air-filling bronchi in an abnormal area, preserved bronchial lumen notwithstanding possible mucus accumulation in the bronchi, the absence of bronchial blockage, and cavity drainage through the bronchus.

Bile duct angulation and tumor vascularity are useful radiographic features for differentiating pancreatic head cancer and intrapancreatic bile duct cancer.

To perform radical resection without leaving residual cancer, surgeons must distinguish between pancreatic head cancer (PHC) and intrapancreatic bile duct cancer (IPBDC) preoperatively. The aim of this study was to establish the points of difference between these two cancers, especially on preoperative multi-detector computed tomography (MDCT) images. The subjects of this study were 28 patients with PHC and proven bile duct invasion who underwent pancreatoduodenectomy (PHC group) and 22 patients with IPBDC and upstream bile duct dilation (IPBDC group). We compared the preoperative clinical and radiographic features, including the bile duct angle, calculated on coronal images of MDCT, and the vascularity of the tumor. The optimal cut-off values for the bile duct angle, the CT value ratio of the tumor (late arterial phase/non-enhanced), and the main pancreatic duct (MPD) ratio (diameter of MPD/diameter of parenchyma) were 110°, 3.0, and 0.2, respectively. Multivariate analysis revealed that a bile duct angle < 110°, a CT value ratio of the tumor < 3, and an MPD ratio ≥ 0.2 were independently associated with PHC. A bile duct angle and CT value reflecting the vascularity of the tumor might be useful radiographic features for differentiating PHC and IPBDC, in addition to MPD dilatation.

Multidetector computed tomography has replaced conventional intravenous excretory urography in imaging of the kidneys: A scoping review of multidetector computed tomography findings in renal tuberculosis.

BackgroundTuberculosis (TB) is a worldwide infectious disease burden, especially in non-developed countries, with increased morbidity and mortality among human immunodeficiency virus (HIV)-infected patients. Extrapulmonary TB is rare and renal TB is one of the commonest manifestations. The end result of renal TB is end-stage renal disease; however, this can be avoided if the diagnosis is made early. The diagnosis of renal TB is challenging because of the non-specific presentation and low sensitivity of clinical tests. Although the sequel of TB infection in the kidney causes varying manifestations depending on the stage of the disease, multidetector computed tomography (MDCT) is capable of demonstrating early findings. We performed a 20-year scoping review of MDCT findings in renal TB to promote awareness.AimTo identify specific MDCT imaging characteristics of renal TB, promote early diagnosis and increase awareness of the typical imaging features.Methods and materialWe searched published and unpublished literature from 1997 to 2017 using a combination of search terms on electronic databases. We followed the Joanna Briggs Institute guidelines.ResultsA total of 150 articles were identified, of which 145 were found through electronic search engines and 5 were obtained from grey literature. Seventy-nine articles that fulfilled our inclusion criteria were reviewed. These included original research, case reports, literature review, organisational reports and grey literature.ConclusionMultidetector computed tomography can reproduce images comparable with intravenous excretory urography; together with advantages of being able to better assess the renal parenchyma and surrounding spaces, it is important in suggesting the diagnosis of renal TB and clinicians should consider including MDCT when investigating patients with recurrent urinary tract infection not responding to usual antimicrobial therapy.

Bioprosthetic aortic valve leaflet thrombosis detected by multidetector computed tomography is associated with adverse cerebrovascular events: a meta-analysis of observational studies.

Leaflet thrombosis (LT) has become increasingly recognised following transcatheter and surgical aortic bioprosthetic valve (ABV) replacement and can be reliably identified by multidetector computed tomography (MDCT). However, it is an ongoing debate whether MDCT-defined LT is associated with adverse cerebrovascular outcomes. We sought to perform a systematic review and meta-analysis in order to assess the incidence and clinical outcomes associated with MDCT-defined leaflet thrombosis following (ABV) replacement. Electronic databases were searched for studies that performed mandatory MDCT imaging following ABV replacement. The primary endpoint was the incidence of cerebrovascular events, defined as a composite of stroke or transient ischaemic attack (TIA). Secondary endpoints included major adverse cerebrovascular and cardiovascular events (MACCE), stroke, TIA, death or myocardial infarction. In total, six studies met the inclusion criteria with 11.6% (198/1,704) of patients having MDCT-defined LT. The prevalence of LT following transcatheter and surgical ABV replacement was 13.2% and 3.6%, respectively. Cerebrovascular events were significantly increased in patients with LT (odds ratio [OR] 3.38, 95% CI: 1.78-6.41, p<0.001). The risk of MACCE (OR 2.10, 95% CI: 1.21-3.64, p<0.001) and TIA (OR 5.86, 95% CI: 2.05-16.75, p<0.001) was also increased in patients with LT, although there were no differences in the incidence of stroke (OR 2.43, 95% CI: 1.00-5.93, p=0.05), death (OR 0.92, 95% CI: 0.42-2.03, p=0.84) or myocardial infarction (OR 1.72, 95% CI: 0.34-9.78, p=0.54) between groups. MDCT-defined LT following ABV replacement is associated with a significantly increased risk of adverse cerebrovascular events. Further prospective studies are required to ascertain whether LT can be prevented or treated with pharmacological strategies.

Multidetector computed tomography imaging characteristics of asymptomatic palatine tonsilloliths: a retrospective study on 3886 examinations

This study aimed to estimate the prevalence of palatine tonsilloliths and analyze their multidetector computed tomography (CT) imaging features. The CT images of 3886 patients (1654 men, 2232 women; mean age, 35.8 years) were reviewed. The distribution, dimension, morphology, and location of each tonsillolith was assessed. The correlation between participant demographic characteristics and the characteristics (prevalence, number, size) of tonsilloliths was determined. The prevalence of palatine tonsilloliths was 30.3%; we identified significant differences in the prevalence and size between men and women. The prevalence of tonsilloliths significantly increased with age (P < .001). The mean number of tonsilloliths per participant was 2.7, and 64.7% of patients had 1 to 2 tonsilloliths. Ovoid-shaped tonsilloliths were the most common (approximately 80%). The centers of the tonsillar crypts contained the majority of the tonsilloliths, 50.3% of which had sizes of 1 to 2 mm. The results, based on a larger sample size compared with previous studies, can be applied as guidelines for the diagnosis of tonsilloliths on CT images.

Clinicopathological and morphological spectrum of gastrointestinal stromal tumours on multi-detector computed tomography.

PurposeTo describe the clinicopathological and morphological features of gastrointestinal stromal tumours (GISTs) on multi-detector computed tomography (MDCT).Material and methodsMDCT (plain and post contrast) images of 25 confirmed cases of GISTs were retrospectively evaluated from our hospital database. The images were analysed for the location, size, growth pattern, attenuation pattern, relation to adjacent structures, presence or absence of ulceration, calcification, metastases, lymphadenopathy, and for any complications such as haemorrhage, intestinal obstruction, etc. Institutional Ethics Committee clearance was obtained prior to the commencement of the study. Statistics used included percentage frequency.ResultsOur study group comprised 14 males and 11 females. The mean age of our study population was 60 years (age range: 40 to 82 years). The mean tumour size was 11.7 cm. The stomach and small bowel accounted for 76% of the primary tumour site. The commonest imaging appearance of GIST observed in our study was that of an exophytic mass (76%) with a heterogenous pattern of enhancement (96%) with intratumoural necrosis (76%). MDCT demonstrated complications in three patients (12%). Six patients presented with metastatic foci (five to the liver and one to the lung), while lymphadenopathy was observed in five patients (20%). Associated complications included intestinal obstruction (8%) and retrogastric haematoma (4%). Incidental findings included uterine fibroid (n = 1), ovarian dermoid (n = 1), and chronic pancreatitis (n = 1).ConclusionsGISTs are predominantly large tumours with a well circumscribed and exophytic pattern on MDCT, with or without cystic/necrotic areas, and they mostly show a heterogenous pattern of enhancement on post-contrast administration.

Three-Dimensional Remnant Pancreatic Volumetry Predicts Postoperative Pancreatic Fistula in Pancreatic Cancer Patients after Pancreaticoduodenectomy

Background: Postoperative pancreatic fistula (POPF) is a serious complication that can occur following pancreaticoduodenectomy (PD). Recent studies suggest that remnant pancreatic volume (RPV) values from preoperative multidetector computed tomography (MDCT) are highly predictive of POPF. We performed three-dimensional (3D) surgical simulation of PD including RPV measurements. The aim of this study was to determine whether 3D-measured RPV is predictive of POPF after PD. Methods: We used the SYNAPSE VINCENT® medical imaging system (Fujifilm Medical Co., Ltd., Tokyo, Japan) to construct 3D images after integrating MDCT and magnetic resonance cholangiopancreatography images. RPV was measured using this 3D image, which simulated actual intraoperative pancreatic parenchymal remnant volume. Ninety-one patients who underwent PD were retrospectively enrolled. Using multivariate analysis, RPV and other well-known POPF risk factors were independently assessed. Results: Multivariate analysis identified high RPV values (hazard ratio [HR] = 8.41, p = 0.01), pancreatic duct diameter < 3.0 mm (HR = 5.48, p < 0.01), no pathological fibrosis (HR = 3.41, p < 0.01), and body mass index > 25 kg/m² (HR = 1.53, p = 0.02) as independent risk factors for POPF. Conclusion: The present study indicates that preoperative 3D-measured RPV is predictive of POPF after PD.

The anatomic analysis of the vidian canal and the surrounding structures concerning vidian neurectomy using computed tomography scans

IntroductionThe type of endoscopic approach chosen for vidian neurectomy can be specified by evaluating the vidian canal and the surrounding sphenoid sinus structures. ObjectiveThe variations and morphometry of the vidian canal were investigated, focusing on the functional correlations between them which are crucial anatomical landmarks for preoperative planning. MethodsThis study was performed using paranasal multidetector computed tomography images that were obtained with a section thickening of 0.625mm of 250 adults. ResultsThe distributions of 500 vidian canal variants were categorized as follows; Type 1, within the sphenoid corpus (55.6%); Type 2, partially protruding into the sphenoid sinus (34.8%); Type 3, within the sphenoid sinus (9.6%). The pneumatization of the pterygoid process is mostly seen in vidian canal Type 2 (72.4%) and Type 3 (95.8%) (p<0.001). The mean distances from the vidian canal to the foramen rotundum and the palatovaginal canal were greater in the vidian canal Type 2 and 3 with the pterygoid process pneumatization (p<0.001). The prevalence of the intrasphenoid septum between the vidian canal and the vomerine crest and lateral attachment which ending on carotid prominence were much higher in vidian canal Type 3 than other types (p<0.001). The mean angle between the posterior end of the middle turbinate and the lateral margin of the anterior opening of the vidian canal was measured as 33.05±7.71°. ConclusionsPreoperative radiologic analysis of the vidian canal and the surrounding structures will allow surgeons to choose an appropriate endoscopic approach to ensure predictable postoperative outcomes.

CT volumetry for gastric adenocarcinoma: association with lymphovascular invasion and T-stages.

PurposeTo determine whether gross tumor volume of resectable gastric adenocarcinoma on multidetector computed tomography could predict presence of lymphovascular invasion and T-stages.ResultsGross tumor volume increased with the lymphovascular invasion (r = 0.426, P < 0.0001) and T stage (r = 0.656, P < 0.0001). Univariate analysis showed gross tumor volume could predict lymphovascular invasion (P < 0.0001). Multivariate analyses indicated gross tumor volume as an independent risk factor of lymphovascular invasion (P = 0.026, odds ratio = 2.284). The Mann-Whitney U test showed gross tumor volume could distinguish T2 from T3, T1 from T2–T4a, T1–T2 from T3–T4a and T1–T3 from T4a (P = 0.000). In the development cohort, gross tumor volume could predict lymphovascular invasion (cutoff, 15.92 cm3; AUC, 0.760), and distinguish T2 from T3 (cutoff, 10.09 cm3; AUC, 0.828), T1 from T2-T4a (cutoff, 8.20 cm3; AUC, 0.860), T1-T2 from T3-T4a (cutoff, 15.88 cm3; AUC, 0.883), and T1-T3 from T4a (cutoff, 21.53 cm3; AUC, 0.834). In validation cohort, gross tumor volume could predict presence of lymphovascular invasion (AUC, 0.742), and distinguish T2 from T3 (AUC, 0.861), T1 from T2-T4a (AUC, 0.859), T1–T2 from T3–T4a (AUC, 0.875), and T1–T3 from T4a (AUC, 0.773).Materials and Methods360 consecutive patients with gastric adenocarcinoma were retrospectively identified. Gross tumor volume was evaluated on multidetector computed tomography images. Statistical analysis was performed to determine whether gross tumor volume could predict presence of lymphovascular invasion and T-stages. Cutoffs of gross tumor volume were first investigated in 212 patients and then validated in an independent 148 patients using area under the receiver operating characteristic curve (AUC) for predicting lymphovascular invasion and T-stages.ConclusionsGross tumor volume of resectable gastric adenocarcinoma at multidetector computed tomography demonstrated capability in predicting lymphovascular invasion and distinguishing T-stages.

Anatomical Variations of Coeliac Axis and Common Hepatic ArterySystematic Analysis of Multi detector Computed Tomography Images

Anatomical Variations of Coeliac Axis and Common Hepatic ArterySystematic Analysis of Multi detector Computed Tomography Images

Transoesophageal echocardiography prior to catheter ablation could be avoided in atrial fibrillation patients with a low risk of stroke and without filling defects in the late-phase MDCT scan: A retrospective analysis of 783 patients.

To test whether multidetector computed tomography (MDCT) could completely replace transoesophageal echocardiography (TEE) to detect left atrial appendage (LAA) thrombi in atrial fibrillation (AF) patients using a large sample size. 783 patients with AF who underwent MDCT and TEE before catheter ablation were retrospectively included. Demographic data were obtained. Two radiologists blinded to clinical data made the imaging diagnosis. Most of the patients (96.2 %) had a CHA2DS2-VASc score (congestive heart failure, hypertension, age ≥ 75 years old (doubled), diabetes, stroke/transient ischaemic attack/thromboembolism (doubled), vascular disease, age 65-74 years, female sex) ≤ 3. Eight thrombi were identified by TEE, all of which were detected by MDCT; no thrombus was observed with TEE without the observation of filling defects by late-phase MDCT scanning in any of the patients. Using TEE as reference standard, the sensitivity, specificity, positive predictive value and negative predictive value of MDCT for thrombus detection were 100 %, 95.74 % (95 % CI 94.33 %-97.15 %), 19.51 % (95 % CI 16.73 %-22.29 %) and 100 %, respectively. For AF patients with low risk of stroke, when MDCT images showed no filling defect in the late phase, TEE prior to catheter ablation can be avoided. • MDCT can help detect the presence of LAA thrombus. • TEE can be avoided when late-phase MDCT shows no filling defect. • TEE is required in patients whose MDCT images indicate thrombus.

Impact of statistical reconstruction and compressed sensing algorithms on projection data elimination during X-ray CT image reconstruction.

To examine the effect of incomplete, or total elimination of, projection data on computed tomography (CT) images subjected to statistical reconstruction and/or compressed sensing algorithms. Multidetector row CT images were used. The algebraic reconstruction technique (ART) and the maximum likelihood-expectation maximization (ML-EM) method were compared with filtered back-projection (FBP). Effects on reconstructed images were studied when the projection data of 360° (360 projections) were decreased to 180 or 90 projections by reducing the collection angle or thinning the image data. The total variation (TV) regularization method using compressed sensing was applied to images processed by the ART. Image noise was subjectively evaluated using the root-mean-square error and signal-to-noise ratio. When projection data were reduced by one-half or three-quarters, ART and ML-EM produced better image quality than FBP. Both ART and ML-EM resulted in high quality at a spread of 90 projections over 180° rotation. Computational loading was high for statistical reconstruction, but not for ML-EM, compared with the ART. TV regularization made it possible to use only 36 projections while still achieving acceptable image quality. Incomplete projection data-accomplished by reducing the angle to collect image data or thinning the projection data without reducing the angle of rotation over which it is collected-made it possible to reduce the radiation dose while retaining image quality with statistical reconstruction algorithms and/or compressed sensing. Despite heavier computational calculation loading, these methods should be considered for reducing radiation doses.