Virtual Whipple: preoperative surgical planning with volume-rendered MDCT images to identify arterial variants relevant to the Whipple procedure

OBJECTIVE: The purposes of this study were to combine a thorough understanding of the technical aspects of the Whipple procedure with advanced rendering techniques by introducing a virtual Whipple procedure and to evaluate the utility of this new rendering technique in prediction of the arterial variants that cross the anticipated surgical resection plane. CONCLUSION: The virtual Whipple is a novel technique that follows the complex surgical steps in a Whipple procedure. Three-dimensional reconstructed angiographic images are used to identify arterial variants for the surgeon as part of the preoperative radiologic assessment of pancreatic and ampullary tumors.     

Primary interpretation of thoracic MDCT images using coronal reformations

OBJECTIVE: The objective of this study was to evaluate the accuracy and efficiency of primary interpretation of thoracic MDCT using coronal reformations as compared with transverse images. SUBJECTS AND METHODS: Fifty patients (18 females, 32 males; age range, 15-93 years; mean age, 63.6 years) underwent 4-MDCT of the chest (detector width, 1 mm; beam pitch, 1.5). Contrast material was administered in 20 of the 50 patients. Coronal and transverse sections were reformatted into 5-mm-thick sections at 3.5-mm intervals. All available image and clinical data consensually reviewed by two thoracic radiologists served as the reference standard. Subsequently, three other thoracic radiologists independently evaluated reformatted coronal and transverse images at two separate review sessions. Each image set was assessed in 58 categories for abnormalities of the lungs, mediastinum, pleura, chest wall, diaphragm, abdomen, and skeleton. Interpretation times and number of images assessed were recorded. Sensitivity, specificity, and interobserver concordance were calculated. Differences in mean sensitivities and specificities were evaluated with Wilcoxon's signed rank test. RESULTS: The most common findings identified were pulmonary nodules (n = 73, transverse images; n = 72, coronal images) and emphysema (n = 45, transverse; n = 40, coronal). The mean detection sensitivity of all lesions was significantly (p = 0.001) lower on coronal (44% +/- 26% [SD]) than on transverse (51% +/- 22%) images, whereas the mean detection specificity was significantly (p = 0.005) higher (96% +/- 5% vs 95% +/- 6%, respectively). Reporting findings for significantly (p < 0.001) fewer coronal images (mean, 63.0 +/- 4.6 images) than transverse images (mean, 91.9 +/- 8.8 images) took significantly (p = 0.025) longer (mean, 263 +/- 56 sec vs 238 +/- 45 sec, respectively). CONCLUSION: Primary interpretation of thoracic MDCT is less sensitive and more time-consuming using 5-mm-thick coronal reformations as compared with transverse images.     

Peroneal tendon subluxation and dislocation: detection on volume-rendered images--initial experience

Institutional review board approval was received and informed consent was not required for this Health Insurance Portability and Accountability Act-compliant study. The purpose of this study was to retrospectively assess the time efficiency of three-dimensional volume-rendered images obtained from multi-detector row computed tomographic data for the diagnosis of peroneal tendon subluxation or dislocation by using the consensus interpretation of multiplanar reformatted (MPR) images as the reference standard. The reference standard was provided by two musculoskeletal radiologists, and two less experienced readers evaluated 37 images in 32 patients (24 men, eight women; mean age, 41 years; age range, 18-75 years) with acute calcaneal fractures. An analysis of variance was used to compare interpretation time, and the Wilcoxon signed rank test was used to analyze diagnostic difficulty. The average time required for diagnosis was significantly shorter with volume-rendered images than with MPR images (reader 1: 42 vs 78 seconds, P<.001; reader 2: 50 vs 69 seconds, P<.01).     

Measurement of structural abnormalities in arthritis using radiographic images

This article reviewed the current methods for scoring radiographic abnormalities in RA with emphasis on reliability. There is disagreement on the expected course of RA with usual treatment and there is no clear resolution of this disagreement although several factors that contribute to this disagreement have been identified. Scoring joint damage has been effective in establishing benefit from drug treatment for nine agents, five within the last 3 years. Scoring will continue to be used to examine the benefit of new agents in the immediate years to come. A panel of experienced readers agreed that some repair of erosion damage was seen with available treatment. The extent of damage that is reversible has not been established and the frequency of any degree of repair remains unknown. Several methods of true measurement of erosions and joint space width have been reported. They have not found a place in daily practice or in research studies, probably because experience is too limited to know whether they are more powerful in detecting real progression of disease than scoring methods. Several problems that are related to standardizing methods of measuring joint space width were identified.     

Opacity transfer function optimization for volume-rendered computed tomography images of the prostate

RATIONALE AND OBJECTIVES: The selection of an opacity transfer function is essential for volume visualization. Computed tomography (CT) scans of the pelvis were used to determine an optimal opacity transfer function for use in radiotherapy. MATERIALS AND METHODS: On sample datasets (a mathematical phantom and a patient pelvis CT scan), standard viewing orientations were selected to render the prostate. Opacity functions were selected via (1) trapezoidal manual selection, (2) trapezoidal semiautomatic selection, and (3) histogram volume-based selection. Using an established metric, the errors using each of these methods were computed. RESULTS: Trapezoidal manual opacity function optimization resulted in visually acceptable images, but the errors were considerable (6.3-9.1 voxel units). These errors could be reduced with the use of trapezoidal semiautomatic selection (4.9-6.2 voxel units) or with histogram volume-based selection (4.8-7.9 voxel units). As each visualization algorithm focused on enhancing the boundary of the prostate using a different approach, the scene information was considerably different using the three techniques. CONCLUSION: Improved volume visualization of soft tissue interfaces was achieved using automated optimal opacity function determination, compared with manual selection.     

Inferior vena cava filter-associated abnormalities: MDCT findings

OBJECTIVE: Deep venous thrombosis from the pelvis or lower extremities has significant morbidity, and subsequent pulmonary embolism has a high mortality rate. Immediate anticoagulation in patients with deep venous thrombosis is crucial in preventing this lethal complication. However, in patients with contraindications for or failure of anticoagulation, inferior vena cava filters reduce mortality by decreasing the incidence of pulmonary embolism. CONCLUSION: In this review, we discuss the various pathologic abnormalities related to inferior vena cava filters, as seen on MDCT images.     

64层螺旋CT结合多平面重建诊断早期胃癌的价值

目的探讨64层螺旋CT横断位结合多平面重建（MPR）对早期胃癌的检出价值。方法回顾性分析30例经病理证实的早期胃癌的CT影像特征,由2名有经验的放射诊断医师分别评估轴位及MPR重建图像对早期胃癌的检出率,意见不同时通过协商达成一致。结果30例患者中,轴位图像检出18例,其检出率18／30;结合MPR图像检出26例,检出率26／30,两者之间的检出率差异有统计学意义（P=0．020）;单纯CT横断位图像T分期准确性为26．67％（8／30）,结合MPR图像T分期准确性为63％（19／30）,两者比较差异有统计学意义（χ2=8．148,P=0．004）。结论64层螺旋CT横断位结合MPR图像能提高早期胃癌的检出率及术前分期的准确性。     

MDCT of thoraco-abdominal trauma: an evaluation of the success and limitations of primary interpretation using multiplanar reformatted images vs axial images

To assess whether independent evaluation of coronal and sagittal reformatted images can replace axial images for primary interpretation of multidetector row computed tomography (MDCT) images in patients with thoraco-abdominal trauma. 111 (M/F 69:42) patients with acute chest or abdominal trauma underwent 16-channel MDCT. Coronal and sagittal multiplanar reformatted (MPR) images were generated from thin-section axial images. Two radiologists independently interpreted the MPR images first followed by axial images for both imaging findings as well as adequacy of image quality. Differences between independent reader review of axial and MPR images were assessed using the Wilcoxon signed rank test. There was no significant difference in soft tissue findings identified on MPR vs axial images for either reader, p = 0.91 and 0.34, respectively. However, both readers identified more skeletal findings on the MPR as compared to the axial images, p = 0.026 and 0.040, respectively. There was no significant difference between the readers in their interpretation of axial (soft tissue, p = 0.56; skeletal, p = 0.65) or MPR (soft tissue, p = 0.32; skeletal, p = 0.65) findings. More skeletal findings were identified during the isolated review of MPR as compared to axial images alone. However, the use of MPR images alone still resulted in an unacceptably high number of missed soft tissue and even skeletal findings. A combined approach where both data sets are simultaneously available is therefore preferred.     

Hilar and suprapancreatic cholangiocarcinoma: value of 3D angiography and multiphase fusion images using MDCT

OBJECTIVE: We evaluated the feasibility of creating 3D and multiphase fusion images of cholangiocarcinoma. The 3D rendering of the biliary tree provide valuable information for planning surgery, including the location of the obstruction and its relationship to the surrounding vessels. CONCLUSION: Our data emphasize that 3D and multiphase fusion images may be an accurate and routinely applicable tool for the diagnosis and therapeutic management of patients with biliary system abnormalities.     

跟腱病变病人腓肠肌和比目鱼肌水肿及脂肪变性的MR成像

目的本研究目的是评价跟腱损伤病人腓肠肌和比目鱼肌的水肿与脂肪变性的发生率。方法对51例(14～84岁,平均51岁)跟腱痛病人进行小腿MRI扫描。比较正常跟腱组、跟腱病组和跟腱部分或完全撕裂组病人中腓肠肌和比目鱼肌水肿与脂肪变性的发生率。结果35%(7/20)的跟腱病     

Oedema and fatty degeneration of the soleus and gastrocnemius muscles on MR images in patients with achilles tendon abnormalities

Objective  

The purpose of this study was to evaluate the frequency of oedema and fatty degeneration of the soleus and gastrocnemius muscles in patients with Achilles tendon abnormalities.     

Hyperattenuating bone marrow abnormalities in myeloma patients using whole-body non-enhanced low-dose MDCT: correlation with haematological parameters

We aimed to establish the role of hyperattenuating medullary abnormalities detected by whole-body non-enhanced low-dose multidetector CT (WBLD-MDCT) in multiple myeloma (MM) patients referred for primary evaluation. 50 consecutive patients with untreated Stage I (n(I) = 11), Stage II (n(II) = 10) and Stage III (n(III) = 29) MM underwent WBLD-MDCT for staging. The number and size of osteolysis, as well as haematologic parameters including paraprotein and beta2-microglobulin levels, were assessed and related to the number, size and density of medullary abnormalities assumed to represent myeloma involvement. Bone marrow abnormalities were found in 2/11 (18%) Stage I, 6/10 (60%) Stage II and 20/29 (69%) Stage III myeloma patients, and did not parallel the incidence of osteolysis. Patients with medullary lesions had higher levels of immunoglobulin A (median, 4730 mg dl(-1) vs 1520 mg dl(-1)), light-chain proteinuria (median, 690 mg dl(-1) vs 214 mg dl(-1)) and IgG paraprotein (median, 3270 mg dl(-1) vs 2610 mg dl(-1)) compared with patients without medullary lesions. In patients with medullary abnormalities, levels of serum beta2-microglobulin were significantly higher than in patients without detectable marrow infiltrates (median, 4.3 mg dl(-1) vs 2.4 mg dl(-1); p = 0.0015). In conclusion, medullary abnormalities visualized by WBLD-MDCT are encountered in all stages of myeloma, including cases without osteolysis. They are associated with significantly elevated serum levels of paraprotein (reflecting tumour mass) and beta2-microglobulin, a prospective prognostic marker for myeloma. The nature and possible prognostic significance of medullary abnormalities detected by WBLD-MDCT therefore warrants further investigation.     

Pulmonary nodule detection on MDCT images: evaluation of diagnostic performance using thin axial images,maximum intensity projections,and computer-assisted detection

This study aimed at evaluating the diagnostic benefits of maximum intensity projections (MIP) and a commercially available computed-assisted detection system (CAD) for the detection of pulmonary nodules on MDCT as compared with standard 1-mm images on lung cancer screening material. Thirty subjects were randomly selected from our database. Three radiologists independently reviewed three types of images: axial 1-mm images, axial MIP slabs, and CAD system detections. Two independent experienced chest radiologists decided which were true-positive nodules. Two hundred eighty-five nodules ≥1 mm were identified as true-positive by consensus of two independent chest radiologists. The detection rates of the three independent observers with 1-mm axial images were 22 ± 4.8%, 30 ± 5.3%, and 47 ± 2.8%; with MIP: 33 ± 5.4%, 39 ± 5.7%, and 45 ± 5.8%; and with CAD: 35 ± 5.6%, 36 ± 5.6%, and 36 ± 5.6%. There was a reading technique effect on the observers’ sensitivity for nodule detection: sensitivities with MIP were higher than with 1-mm images or CAD for all nodules (F-values = 0.046). For nodules ≥3 mm, readers’ sensitivities were higher with 1-mm images or MIP than with CAD (p < 0.0001). CAD was the most and MIP the less time-consuming technique (p < 0.0001). MIP and CAD reduced the number of overlooked small nodules. As MIP is more sensitive and less time consuming than the CAD we used, we recommend viewing MIP and 1-mm images for the detection of pulmonary nodules. This study was presented at the ECR 2006.     

Evaluation of abdominal aortic aneurysm for endovascular stent-grafting with volume-rendered CT images of vessel lumen and thrombus

PURPOSE: To evaluate the accuracy of CT images of abdominal aortic aneurysm (AAA) with volume-rendered (VR) display of vessel lumen and thrombus and to evaluate its usefulness in the planning of stent-grafting. MATERIALS AND METHODS: Helical CT was performed in 11 patients with AAA. Volume data of the vessel lumen and thrombus were separately extracted, and the VR images were reconstructed. Vessel measurements were made by five radiologists and compared with the axial and multiplanar reconstruction (MPR) images. Angiography and intravascular ultrasonography were used as standard references. The relations of aneurysmal sac to the major arterial branches and the subjective overall diagnostic value were evaluated by using a continuous rating scale. RESULTS: Accuracy of measurements was higher on VR images than on axial/MPR in 7 of 13 regions. Interobserver variance of VR images was smaller in 7 of 14 regions. Detection of renal and internal iliac artery involvements was better on VR images (p<0.05). Overall diagnostic value was also higher on VR images (p<0.05). CONCLUSION: VR CT images of vessel lumen and thrombus are supportive of and supplementary to conventional axial/MPR images in planning stent-grafting for AAA.     

Can independent coronal multiplanar reformatted images obtained using state-of-the-art MDCT scanners be used for primary interpretation of MDCT of the abdomen and pelvis? A feasibility study

PurposeTo evaluate if coronal reformatted images can be used for primary interpretation of MDCT of the abdomen and pelvis using 64-slice MDCT.Materials and methodsIRB approval was obtained. We reviewed MDCT studies of the abdomen and pelvis of 220 consecutive patients performed with 64 row MDCT with constant scanning parameters. Based on a 0.625 mm raw data set, transverse images were reconstructed at 5 mm and coronal images at 3 mm using standard reconstruction algorithms. Reader familiarity was achieved by simultaneous evaluation of transverse and coronal reformats in an initial group of 20 separate cases for findings in consensus. Two subsequent phases of image analysis were then performed in two groups of 100 patients each. In the first phase two radiologists evaluated the added utility of simultaneous review of MDCT of transverse and coronal reformatted images over transverse images alone in 100 consecutive patients referred for MDCT of the abdomen and pelvis. In the second phase, the same radiologists evaluated whether coronal multiplanar reformats could be used for primary interpretation of MDCT of the abdomen and pelvis in a separate but similar cohort of 100 consecutive abdominopelvic MDCT studies. The number of lesion(s), their location, size of smallest lesion, presence of artifacts and likely diagnosis were noted at each image interpretation. Image quality and confidence for interpretation was evaluated using five-point and three-point scale, respectively. The time required for primary interpretation of coronal reformats and transverse images were recorded. Statistical analysis was performed using Wilcoxon signed rank test.ResultsBoth readers detected additional findings (n = 37, 35), respectively, on simultaneous review of transverse and coronal reformats as compared with transverse images alone (p < 0.001). Excellent interobserver agreement was noted (r = 0.94–0.96). Both readers detected additional findings (n = 62, 53), respectively, on independent review of coronal reformats as compared with transverse images alone (p < 0.001). Readers’ confidence was also found to be higher on coronal evaluations as compared to axial images (p < 0.01). There was good interobserver agreement between the two readers.ConclusionIndependent coronal multiplanar reformatted images obtained using state-of-the-art MDCT scanners show promise as the preferred orientation and can be useful for primary interpretation of MDCT of the abdomen and pelvis.     

Hemodynamic characterization of focal nodular hyperplasia using three-dimensional volume-rendered multidetector CT angiography

OBJECTIVE: The goal of this study was to show the ability of three-dimensional multidetector CT angiography to display the angioarchitecture of focal nodular hyperplasia. CONCLUSION: CT angiography with volume rendering shows the anomalous feeding artery and hepatic draining veins that are characteristic of focal nodular hyperplasia. These features may be helpful in distinguishing focal nodular hyperplasia from other lesions.     

Nonatherosclerotic cardiovascular findings on MDCT coronary angiography: a selection of abnormalities

OBJECTIVE: Improvements in MDCT coronary angiography allow imaging of the coronary arteries that rivals invasive coronary angiography. Recent studies have shown high sensitivity and specificity in detecting coronary artery disease. But in the course of interpretation, other significant abnormalities may be encountered in addition to atherosclerotic plaques. CONCLUSION: We present a selection of nonatherosclerotic cardiovascular findings that were detected with coronary CT angiography performed on a 64-MDCT scanner.     

Anterior tibial tendon abnormalities: MR imaging findings

PURPOSE: To retrospectively evaluate the magnetic resonance (MR) imaging findings of anterior tibial tendon (ATT) abnormalities. MATERIALS AND METHODS: Institutional review board approval was not necessary for review of patient images and was granted for examination of the volunteers; informed consent was obtained. MR imaging findings in 28 consecutive patients (20 women, eight men; mean age, 63.2 years) clinically suspected of having an ATT abnormality were compared with those in an age- and sex-matched control group of 28 asymptomatic volunteers (20 women, eight men; mean age, 62.9 years). Surgical correlation was available for 11 patients. The short-axis diameter of the ATT and the longitudinal extent of signal intensity abnormalities were measured (Mann-Whitney U test). Signal intensity abnormalities of the ATT and irregularities of the underlying tarsal bones were analyzed in consensus by two blinded radiologists (chi2 test). RESULTS: In the symptomatic group, three cases of tendinosis and 13 partial and 12 complete ATT tears were diagnosed. In 11 cases (one case of tendinosis and two cases of partial and eight cases of complete ATT tear), surgical correlation was available and the MR imaging diagnosis was confirmed. In the asymptomatic group, four cases of tendinosis of the ATT were seen. The ATT diameter was significantly thicker in symptomatic patients at 1 cm (5.1 vs 3.1 mm in control group, P < .001), 3 cm (5.8 vs 3.4 mm, P < .001), and 6 cm (5.4 vs 4.3 mm, P = .006) proximal to the distal point of insertion. Most ATT abnormalities (in 23 [82%] of 28 patients) were located within the first 3 cm proximal to the insertion. Signal intensity abnormalities were seen in the anterior portion of the ATT in two (7%) of the 28 symptomatic patients and in the posterior portion in 11 (39%); diffuse involvement was seen in 15 (54%). Bone spurs on the navicular surface (nine [32%] patients vs no [0%] control subjects, P = .001), a ridged shape of the medial surface of the medial cuneiform bone (13 [46%] vs one [4%], P < .001), and osteophyte formation at the first tarsometasarsal joint (eight [29%] vs two [7%], P = .036) were significantly more common in the symptomatic patient group. CONCLUSION: Characteristic findings of ATT abnormalities include tendon thickening (> or =5 mm) and diffuse or posterior signal intensity abnormalities of the tendon within 3 cm from the distal point of insertion.     

Image quality dependence on in-plane positions and directions for MDCT images

Objective

The present study was performed to examine the dependence of image quality on in-plane position and direction in computed tomography (CT) imaging using the modulation transfer function (MTF), noise power spectrum (NPS) and analysis of signal-to-noise ratio (SNR). For detailed analysis of SNR, the low-contrast detectability was compared using simulated small low-contrast objects.

Materials and methods

Three models of multidetector-row CT (MDCT) were employed. The measurement positions for MTF were set to the isocentre and several peripheral areas, and NPS and SNR were calculated for the isocentre and 128 mm off-centre. To evaluate directional dependence, the one-dimensional physical properties were measured separately in the radial and azimuthal directions. Seven radiological technologists also performed a perceptual detection study at the different in-plane positions using computer-simulated low-contrast images.

Results

The results of MTF and SNR differed between the isocentre and the peripheral area. The MTF values also tended to decrease with distance from the isocentre, and the SNR values in the low frequency range for the peripheral area were superior to those for the isocentre. In the detection study, the low-contrast detectability in the peripheral area was 13-40% higher than the value in the isocentre.

Conclusion

The results of the present study indicated that clinical CT images have remarkable non-uniformity of image quality. Therefore, the detailed analysis performed in this study will provide useful information for the development of advanced image processing applications, such as computer-aided diagnosis (CAD) and de-noising of CT images.