Multislice Computed Tomography Examination Research Articles

Oral cleft volumetric assessment by 3D multislice computed tomographic images

The aim of this study was to determine the quantitative assessment of bone volume defects using multislice computed tomography (CT), and to establish an image processing protocol that enables this analysis. Bone defects were created in nine dry skulls, to mimic oral clefts. All the defects were modelled with wax, following the contralateral shape of the alveolo-palatal region. The wax was used to obtain the real volume of the cleft (gold standard). The skulls (with and without wax) were submitted to multislice CT examination, and the images were processed in an independent workstation using volumetric software. All the images were analysed twice, by two examiners at different times, performing intra- and inter-examiner analyses. The results show that the protocol for image processing has high efficiency ( P = 0.995). Multislice CT showed excellent results, with high reliability in the study of bone defect volume ( P = 0.997). The intra- and inter-observer analysis showed no statistically significant differences. It was demonstrated that multislice CT is a reliable technique in the volumetric assessment of bone defects in the alveolar and palatal regions, and that this method was efficient for calculating the volume of the clefts.

Adult patient radiation doses from non-cardiac CT examinations: a review of published results.

CT is a valuable tool in diagnostic radiology but it is also associated with higher patient radiation doses compared with planar radiography. The aim of this article is to review patient dose for the most common types of CT examinations reported during the past 19 years. Reported dosimetric quantities were compared with the European diagnostic reference levels (DRLs). Effective doses were assessed with respect to the publication year and scanner technology (i.e. single-slice vs multislice). Considerable variation of reported values among studies was attributed to variations in both examination protocol and scanner design. Median weighted CT dose index (CTDI(w)) and dose length product (DLP) are below the proposed DRLs; however, for individual studies the DRLs are exceeded. Median reported effective doses for the most frequent CT examinations were: head, 1.9 mSv (0.3-8.2 mSv); chest, 7.5 mSv (0.3-26.0 mSv); abdomen, 7.9 mSv (1.4-31.2 mSv); and pelvis, 7.6 mSv (2.5-36.5 mSv). The introduction of mechanisms for dose reduction resulted in significantly lower patient effective doses for CT examinations of the head, chest and abdomen reported by studies published after 1995. Owing to the limited number of studies reporting patient doses for multislice CT examinations the statistical power to detect differences with single-slice scanners is not yet adequate.

Associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in gastric cancer

To explore the associations of triple-phase enhancement multi-slice CT scan with histological differentiation and lymphovascular invasion in advanced gastric cancer. Patients with gastric cancer undergoing surgical resection between January 2006 and December 2009 were included, all of whom underwent routine and two-phase contrast enhancement multi-slice CT examinations of the upper abdomen before surgery. Patients with incomplete data were excluded. Postoperative specimens were used for evaluation of histological differentiation, microscopic lymphovascular invasion, and CD34 and D2-40 expression. Associations between contrast enhancement ratio (CER) of triple-phase multi-slice CT scan and differentiation as well as lymphovascular invasion were analyzed. A total of 64 patients were included. There were significant associations between CER and tumor differentiation (P<0.05). Compared to those without microvascular invasion, CER of the arterial phase in gastric cancer with microvascular invasion was significantly higher (0.61±0.28 vs. 0.46±0.14, P<0.05), and that of the arterial-parenchymal phase was significantly lower(1.81±0.39 vs. 2.28±0.80, P<0.05). However, gastric cancers with lymphatic invasion were associated with significantly higher CER of the parenchymal phase than their counterparts(1.25±0.57 vs. 1.00±0.35, P<0.05). CER of triple-phase multi-slice CT scan can reveal the differentiation of gastric cancer and is associated with microvascular and lymphatic invasion.

Traumatic diaphragmatic rupture: the diagnostic value of multiplanar reformation in multi-slice spiral CT examination

Objective To investigate the diagnostic value of multiplanar reformation (MPR)reconstruction for the detection of traumatic diaphragmatic rupture (TDR) in multi-slice CT examination.Methods Thirty six cases with thoracoabdominal trauma, including 21 cases with and 15 cases without TDR confirmed by surgery, received multi-slice CT examination. They were enrolled in this study. Three experienced radiologists retrospectively analyzed the axial and MPR images. The diagnostic criteria for TDR included abnormally elevated hemidiaphragm, diaphragmatic discontinuity, the collar sign or dependent viscera sign. Referenced to surgical results, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of axial and MPR images in detection of TDR were calculated. The McNemar was used to investigate the differences between axial and MPR images in the detection of diaphragmatic discontinuity and collar sign, and the differences between axial and MPR images of these two signs in TDR diagnosis. Results The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of axial images in detection of TDR were 71% ( 15/21 ), 80% ( 12/15 ), 83% ( 15/18 ),67% ( 12/18 ) and 75% ( 27/36 ), respectively; of MPR images, they were 86% ( 18/21 ), 93%(14/15), 95% ( 18/19 ), 82% ( 14/17 ) and 89% ( 32/36), respectively. By axial images, twelve diaphragmatic defects or interrupts were identified in nine cases, and collar sign was identified in six cases. By MPR, 20 diaphragmatic defects or interrupts were identified in 15 cases ( P = 0.125 ), and collar sign was identified in 14 cases (P =0.021 ). The sensitivity and specificity of diaphragmatic defects or interrupts for TDR diagnosis in axial images were 43% (9/21) and 80% ( 12/15 ), respectively;in MPRimages, they were71% (15/21) (P=0.125)and93% (14/15) (P=0.500), respectively.The sensitivity and specificity of collar sign for TDR diagnosis in axial images were 29% (6/21) and 100% ( 15/15), respectively; in MPR images, they were 67% ( 14/21 ) (P =0. 021 ) and 100% (15/15)( P = 1.000), respectively. Conclusions MSCT presented good sensitivity, specificity and accuracy for the diagnosis of TDR. MPR images were useful supplements for axial images in TDR diagnosis which improved the diagnosis. Key words: Wounds and injuries; Tomography,X-ray computed; Comparative study

Angiofollicular Lymphoid Hyperplasia—An Unusual Cause of Axillary Artery Pseudoaneurysm

Angiofollicular lymphoid hyperplasia (Castleman's disease) is a rare inflammatory condition. Its cause is unknown and it can be both localized and general. Eighty-six percent of lesions are found in the mediastinum or hilum, and 91% are of the hyaline vascular type. Although Castleman's disease is primarily involving the chest and retroperitoneum, it may also involve neck and axilla in 2-4% of cases. In this article, we present a very rare case of Castleman's disease causing axillary artery pseudoaneurysm. A 30-year-old woman patient presented with pulsating tumefaction of the left arm which was 3.5 x 10 cm in size, and became evident 15 days before admission. History revealed that she suffered trauma of the left upper arm in childhood; therefore, it was suspected that tumefaction may be due to a post-traumatic aneurysm. Duplex scan and multislice computed tomography examinations were performed and an axillary artery pseudoaneurysm was diagnosed. Since intraoperatively the tumefaction resembled the tumorous formation but not the aneurysmal wall, specimens were sent for pathohistological analysis. Arterial reconstruction was performed using autologous vein graft. Pathohistological findings showed vascular type of angiofollicular lymphoid hyperplasia. Although angiofollicular lymphoid hyperplasia is rarely localized in the axillary area, this disease should also be considered when axillary artery pseudoaneurysm is diagnosed.

Thyroid Cartilage Ossification and Multislice Computed Tomography Examination: A Useful Tool for Age Assessment?

Many authors have studied the thyroid cartilage ossification process using radiographic features for age estimation of individuals. Their results were various: Sugiyama reported excellent correlation coefficients between ossification rates and civil age, unlike most other authors. We hypothesized that recent advances in imaging techniques would enable more precise evaluation of the ossification of the thyroid cartilage. We retrospectively analyzed the CT scans of 312 French patients using postprocessing software to examine the pattern of thyroid cartilage ossification, calculating the ossified volume of the cartilage on 3D reconstructions. Pearson's correlation coefficients for volume were 0.73 for men and 0.75 for women (standard error 18.02 and 17.06), indicating considerable inter-individual variability. Although a correlation between civil age and morphological changes was found, these methods based on thyroid cartilage ossification were not accurate enough for the assessment of individual age.

Herniation pits and cystic-appearing lesions at the anterior femoral neck: an anatomical study by MSCT and µCT

To determine distinguishing features between herniation pits (HPs) and other cystic-appearing lesions at the anterior femoral neck in multi-slice computed tomography (MSCT) and micro-computed tomography (microCT) examinations. Institutional review board approval was obtained to examine 37 proximal femora of 23 cadaveric specimens (mean age available in 19 cadavers, 83 years; range 68-100 years; 9 female, 8 male, 6 unknown). All 37 femora were investigated by MSCT. 23 femora, which revealed cystic-appearing lesions at the anterior femoral neck in MSCT examinations, were additionally examined by microCT. Cystic-appearing lesions were categorized by their location, sclerotic margin, demarcation and shape in MSCT with assessment of inter-observer agreement. Detailed cortical and trabecular properties were evaluated in microCT examinations. There were seven HPs in three femora. There were a number of abnormalities potentially imitating HPs, including focal osteoporosis (13 in 13 femora), degenerative changes (5 in 4 femora) and trabecular restructuring (5 in 4 femora) at the anterior femoral neck. HPs were differentiated on the basis of their subchondral/subcortical location, completely surrounding sclerosis, clear demarcation and round-to-oval shape in MSCT. Because of their location and their microscopic appearance, HPs seem to resemble intra-osseous ganglia at the anterior femoral neck. HPs have to be differentiated from other cystic appearing lesions at the anterior femoral neck to avoid overestimation of their incidence in the context of diagnosis of femoroacetabular impingement.

Dosimetry and image quality of four dental cone beam computed tomography scanners compared with multislice computed tomography scanners

The aim of this study was to evaluate the radiation dose and image quality of four dental cone beam CT (CBCT) scanners, and to compare them with those of two multislice CT (MSCT) scanners. Tissue doses were measured using a tissue-equivalent anthropomorphic RANDO Head Phantom((R)) with thermoluminescence dosemeters (TLD). An RSVP Head Phantom(TM) with a specially designed cylindrical insert was used for comparison of image quality and absorbed dose. Image quality was evaluated in the form of contrast-to-noise ratio (CNR) and modulation transfer function (MTF). Using standard imaging parameters, the effective doses varied between 14 microSv and 269 microSv (International Commission on Radiation Protection (ICRP) 1990) and 27 microSv and 674 microSv (ICRP 2008) with the CBCT scanners, and between 350 microSv and 742 microSv (ICRP 1990) and 685 microSv and 1410 microSv (ICRP 2008) with the MSCT scanners. The CNR of the CBCT and MSCT scanners were 8.2-18.8 and 13.6-20.7, respectively. Low-dose MSCT protocols provided CNRs comparable with those from CBCT scanners. The 10% MTF of the CBCT scanners varied between 0.1 mm(-1) and 0.8 mm(-1), and was 0.5 mm(-1) for all the MSCT protocols examined. CBCT scanners provide adequate image quality for dentomaxillofacial examinations while delivering considerably smaller effective doses to the patient. Large variations in patient dose and image quality emphasize the importance of optimizing imaging parameters in both CBCT and MSCT examinations.

Low dose CT protocol: Capability for early detection of lung carcinoma

Lung carcinoma is the most common cause of death among men who died from cancer; also, among women, the incidence of this disease is on the increase. Use of multislice computed tomography (MSCT) has enhanced detection capability for pulmonary nodules. Nowadays, low radiation dose CT technique (LDCT) increases interest in lung cancer screening. This study is a part of the project whose aim is early diagnosis and well-timed treatment of lung carcinoma. Participants in this screening were above the age of 40, both smokers and non-smokers, who have undergone MSCT examination of lungs following low-dose protocol (LDCT). In the first ten months of the study, 375 volunteers have been examined. Overall number of detected nodules was 361; and 303 of these nodules have been characterized as non-calcificated. 95 participants (24.27%) had at least one non-calcificated nodule. 17 patients were referred to pulmologist and for further clinical evaluation. LDCT significantly increases detection of small, non-calcificated pulmonary nodules, and, therefore, gives higher opportunity to detect early lung carcinoma.

Quantitative study of therapeutic efficacy on early intervention of hyperbaric oxygen to model of steroid-induced avascular osteonecrosis of femoral head by multi-slice perfusion imaging

To quantitatively evaluate the hemodynamic status in animal models of steroid-induced avascular osteonecrosis of femoral head (SANFH) by multislice CT (MSCT) perfusion imaging, and estimate the therapeutic efficacy on early intervention of hyperbaric oxygen (HBO) to improve the region blood flow (rBF) of ischemic femoral head. Forty-eight New Zealand male rabbits were injected with Escherichia coli endotoxin and methyl-prednisolone to establish SANFH models and then divided into 3 subgroups to undergo MSCT to measure the rBF, regional blood volume (rBV), and mean transit time (MTT) to obtain perfusion maps at the femoral head epiphysis, metaphysic, and neck of femur, and then were killed to undergo histological examination of the bilateral femoral heads 2, 4, and 6 weeks later respectively (Groups M(2), M(4), and M(6)). Twenty-four rabbits underwent HOB treatment after the second injection of E. c. endotoxin for 1-3 courses respectively (Groups H(1), H(2), and H(3)), and then underwent MSCT and pathological examination as described above. Eight rabbits were used as controls (Group N). (1) The rBF values of Groups M(2), M(4), and M(6) were all significantly lower than that of Group N (P < 0.001, < 0.001, and < 0.002). The rBF value of femoral head epiphysis of Group M(2) was remarkably lower than that of Group N, decreased to the lowest in Group M(4), and re-increased in Group M(6). The rBV value demonstrated similar change pattern in femoral head epiphysis. The MTT values of Groups M(2) and M(4) were longer than that of Group N, and then re-decreased in Group M(6). (2) It did differ significantly between the perfusion data of different femoral head anatomic regions in Groups M(2), M(4), M(6) and N (rBF: F = 52.190, P < 0.001; rBV: F = 42.677, P < 0.001; MTT: F = 3.09, P = 0.048). The changes of the perfusion data in femoral head epiphysis were more significant than those in other anatomic regions. (3) There were no statistically significant differences in the rBF value of the femoral head epiphysis and metaphysis (F = 2.081, P = 0.115; F = 1.142, P = 0.341), in the rBV value of the femoral metaphysis and neck of femur (F = 2.642, P = 0.059; F = 1.568, P = 0.209), and the MTT value of all the anatomic regions (F = 1.111, P = 0.347) among Groups H(1), H(2), H(3), and N. The rBF values of Groups H(1), H(2), and H(3) were statistically higher than those of the corresponding phase model groups (all P < 0.05). Able to detect hemodynamic status of femoral head, MSCT perfusion imaging technique may be used in the early detection of SANFH. Early intervention of HBO therapy can improve the blood perfusion of femoral head.

Multimodality Preoperative Planning and Postoperative Follow-up of a Hybrid Cardiac Intervention

We describe the case of a 59-year-old man who had aortic regurgitation and a hypoplastic aortic valve and for whom an echocardiography evaluation revealed a vascular tumor in the roof of the left atrium, which was suspected to be a hemangioma. After undergoing preoperative invasive catheter coronary angiography, echocardiography, and multislice computed tomography examinations, the patient underwent an aortic miniroot replacement. Intraoperative findings confirmed the findings of the preoperative evaluations. The tumor, although macroscopically verified as a hemangioma, was not resected because of the tumor's position and size, and the threat of uncontrollable bleeding. After an uneventful postoperative clinical course, a subsequent successful transcatheter coil occlusion of the coronary fistula from the left circumflex coronary artery was performed as an alternative to surgical resection of the tumor. This case emphasizes the future role of a multimodality hybrid approach for diagnosis, planning (different 2- and 3-dimensional imaging modalities), and treatment in the form of combining interventional (transcatheter) and surgical (open heart) techniques, which could optimize different treatment strategies. This approach could be further improved by increasing the installations of hybrid operating rooms.

Prevalence of left main coronary artery disease among patients referred to multislice computed tomography coronary examinations

We have evaluated the prevalence of left main coronary artery disease (LMCAD) among patients referred to multislice computed tomography (MSCT) coronary angiography examinations. The study Group comprised of 1,000 consecutive patients (750 male and 250 female; mean age 53+/-12 years) who underwent successful 64-slice MSCT examinations. Left main coronary artery (LMCA) was classified into three Groups: normal LMCA; nonsignificant LMCAD with coronary plaques resulting in obstructions <or=50%; and significant LMCAD corresponding to obstructions >50%. We have found that 24 patients (2.4%) had significant LMCAD. Additional 200 patients (20%) had nonsignificant LMCAD. Univariate analysis revealed that LMCAD was associated with age, male gender, diabetes, hypertension, hyperlipidemia, typical symptoms, history of previous myocardial infarction and previous percutaneous coronary intervention. Only age and male gender were found as independent predictors for LMCAD in multivariate analysis (P < 0.001 and P = 0.001, respectively,). Angiographic follow-up was avaliable for the 24 patients with significant LMCAD, and conventional coronary angiography confirmed the presence of significant LMCAD in all of these patients. Significant LMCAD was found in 2.4% of the 1,000 patients referred to 64-slice MSCT examinations. Age and male gender were the independent predictors for LMCAD.

Correlación arteriográfica en 30 pacientes con patología vascular renal diagnosticada mediante TC multicorte

To determine the usefulness of multislice computed tomography (MSCT) in the evaluation of renal vascular disease against a gold standard of digital subtraction angiography (DSA). We evaluated 30 patients with arterial hypertension and/or kidney failure that underwent MSCT to rule out a vascular cause and DSA to confirm a vascular cause suspected at MSCT. MSCT examinations were performed on a 10-detector scanner with intravenous administration of 80 ml of iodinated contrast (300 mg iodine/ml) at a flow rate of 5 ml/s. A total of 71 renal arteries, 56 main and 15 accessory, were evaluated. Arterial stenoses were classified as: grade 0 (normal artery), grade I (stenosis < 50%), grade II (> or = 50% and < 70%), grade III (> or = 70%), grade IV (occlusion). Stenosis > or = grade II was considered hemodynamically significant. The findings at MSCT and DSA were identical in 56 (78.8%) renal arteries; MSCT overestimated the degree of stenosis in 13 (18.3%) cases. All grade III stenoses were detected at MSCT. In the diagnosis of hemodynamically significant stenosis, MSCT had a sensitivity of 96.5%, specificity 78.5%, accuracy 85.9%, positive predictive value 75.6%, and negative predictive value 97%. MSCT is a good noninvasive imaging technique for the evaluation of renal vessels; it is useful for screening patients with kidney disease to rule out potentially treatable vascular causes.

Multiple Mycotic Aneurysms of the Pulmonary Arteries Resolving With Conservative Management

Mycotic pulmonary artery aneurysms are rare but potentially fatal complications of infective endocarditis. Three mycotic aneurysms developed in a 22-year-old female patient who had a history of intravenous drug use. She suffered from Staphylococcus aureus pneumonia and infective endocarditis. The patient was managed conservatively with antibiotics. She did not have hemoptysis during a prolonged hospital stay. Several multislice computed tomography examinations were performed to follow these aneurysms over a period of 19 months. The 2 smaller aneurysms had resolved by 9 weeks postdevelopment. The largest aneurysm was stable at 9 weeks and was smaller at 19 months, but it had not yet completely resolved. The literature on this rare condition was reviewed and its prognosis and management were discussed.

Unusually extensive head trauma in a hydraulic elevator accident: Post-mortem MSCT findings, autopsy results and scene reconstruction

Accidental or intentional falls from a height are a form of blunt trauma and occur frequently in forensic medicine. Reports describing elevator accidents as a small subcategory of falls from heights are rare in the medical literature and no report on injury patterns or scene reconstruction of such an accident was found. A case of an accident in a hydraulic elevator with a man falling 3m was examined using post-mortem multi-slice computed tomography (MSCT) and autopsy. The man suffered an unusually extensive trauma and died at the scene. Post-mortem MSCT examination showed a comminute fracture of the skull, the right femur and the first lumbar vertebra. Severe lacerations of the brain with epidural, subdural and subarachnoidal haemorrhages over both hemispheres were diagnosed. Autopsy confirmed these findings. To reconstruct the accident we used radiological and autopsy results as well as findings at the scene.

Radiological detection of post-oesophagectomy anastomotic leak — a comparison between multidetector CT and fluoroscopy

The purpose of this study was to directly compare CT with fluoroscopy for the diagnosis of occult anastomotic leak following oesophagectomy. Patients undergoing oesophagectomy and gastric conduit formation for the treatment of oesophageal cancer were eligible for inclusion. Imaging was performed 6-8 days post-operatively. Patients underwent multislice CT examination of the chest and abdomen with a bolus of oral contrast, followed by fluoroscopic water-soluble contrast swallow (with subsequent use of barium if this was normal). The studies were reviewed by a consultant radiologist, who was blinded to the results of the other modality. Images were reported as showing "no leak", "possible leak" or "definite leak". The presence of mediastinal gas or fluid or extraluminal contrast at CT was recorded. The clinical outcome after reinstituition of oral intake was used as a reference standard. Patient preference for modality was recorded. 52 patients were recruited. Four were found to have leak on CT and fluoroscopy. 11 had possible leak at CT, but normal fluoroscopy: 2 of these had a leak confirmed later, whereas 9 had no leak. 37 had normal CT and fluoroscopy findings, and remained clinically well. The sensitivity, specificity, positive and negative predictive values were 100%, 80%, 40% and 100%, respectively, for CT, and 67%, 100%, 100% and 96%, respectively, for fluoroscopy. The positive predictive value of mediastinal air, air/fluid and extraluminal contrast were 25%, 75% and 50%, respectively. 35 patients found CT more tolerable. In conclusion, CT was better tolerated and more sensitive but less specific than fluoroscopy for detecting occult anastomotic leak.

Lipoma of the right atrium

A 66-year-old asymptomatic woman was admitted to our hospital with the diagnosis of a right atrial mass detected on an outside transthoracic echocardiogram and confirmed on transesophageal echocardiography. Physical examination and basal electrocardiogram were normal. Transthoracic echocardiography revealed a 3.8 x 2.5 cm echogenic mass in the right atrium. A multislice CT examination demonstrated a right atrial mass with a fat density ranging from -80 to -110 HU. The patient had a successful surgical excision of the mass, and the diagnosis of lipoma was confirmed on histopathological examination.

Principles of CT: Multislice CT

This article describes the principles and evolution of multislice CT (MSCT), including conceptual differences associated with slice definition, cone beam effects, helical pitch, and helical scan technique. MSCT radiation dosimetry is described, and dose issues associated with MSCT-and with CT in general-as well as techniques for reducing patient radiation dose are discussed. Factors associated with the large volume of data associated with MSCT examinations are presented.

Multi-slice computed tomography and the detection of anomalies of coronary arteries

Congenital anomalies of the coronary arteries, even if rare, may have sudden death or myocardial infarction as the first clinical manifestations: thus, it is clear that an early diagnosis has a paramount importance for patients at risk. We present a set of cases advocating the use of multi-slice computed tomography (MSCT) in the detection of coronary artery anomalies. The majority of cases had previously undergone conventional coronary angiography, which, despite being considered the gold standard for the diagnosis of the coronary artery pathologies, often yielded incomplete results. In 439 consecutive patients examined over 22 months by MSCT for the study of heart and coronary arteries, 11 were diagnosed for anomalous coronary artery. All patients were symptomatic for one or more of the following: chest pain, dyspnoea, palpitations, myocardial infarction and resuscitated cardiac arrest. Eight patients had previously undergone a coronary angiography. In the selected patients, seven different types of coronary anomalies were found by MSCT examination. In all cases, this technique was able to recognize the origin of the anomalous coronary artery, its three-dimensional course and its spatial relationship with the adjacent structures, even when conventional coronary angiography was performed but was unable to provide sufficient information for a correct and complete diagnosis. MSCT is an accurate technique for detecting coronary artery anomalies and visualizing their three-dimensional origin and course, and their relationship with the great vessels. It may be considered as the first-choice imaging modality when an anomalous coronary artery is suspected.

Accuracy of linear measurements using dental cone beam and conventional multislice computed tomography

The aim of this study was to evaluate the accuracy of linear measurements obtained with dental cone beam CT (CBCT) and multislice CT (MSCT) by altering radiation doses using pre-operative planning of the placement of oral implants as a model. A human cadaver mandible was examined in two edentulous areas and one dentate area using CBCT and MSCT. The mandible was examined both dry and immersed in sucrose solution isointense with soft tissue. Two readers measured four linear distances twice from each section. The mandible was cut into 4 mm thick slices at three marked places. These slices were microradiographed and used as the gold standard for measurements from each section. The intraclass correlations between the intra- and interobserver readings obtained with the different methods showed almost perfect matches. The measurement error (ME) showed significant differences between the methods studied (P = 0.022): the mean ME was 4.7% for CBCT and 8.8% for MSCT of the dry mandible, 2.3% and 6.6%, respectively, for the mandible immersed in sucrose solution and 5.4% for low-dose MSCT. Lowering the MSCT radiation dose to less than a quarter of its conventional original value did not significantly affect the ME. CBCT is a reliable tool for implant-planning measurements when compared with MSCT. In this study, a considerable radiation dose reduction could be achieved with low-dose MSCT examinations without a major loss of measurement accuracy.