Biomedical subjects

T Helmberger

Publications and source records attributed to T Helmberger.

At least 19 recordsLinked to original sources

PubMed2003

[MRI in Crohn's disease after transduodenal contrast administration using negative oral MRI contrast media].

PURPOSE: To compare the efficacy and quality of conventional and MR enteroclysis with different filling methods regarding the assessment of extension and extraluminal manifestations in Crohn's disease. MATERIAL AND METHODS: 190 patients with known Crohn's disease were studied following small bowel enteroclysis, after oral administration or direct transduodenal filling in the MRI-department.T1- and T2-weighted breathhold MRI-scans w/o spectral fat suppression w/o i.v. Gd-DTPA were applied using negative oral superparamagnetic contrast media. RESULTS: Typical findings were marked bowel wall thickening with laminated wall contrast enhancement. In 135 patients 98,2% of affected bowel segments, 97,5% of stenoses and all 16 fistulas were detected, when conventional enteroclysis was employed as standard of reference. Additional important extraluminal findings such as ileoileal (n = 18), ileosigmoidal adhesions (n = 12), extraluminal abscesses (n = 35) and pseudotumors (n = 8) were visualized in 73/135 patients. Concerning the distension of jejunum and ileum, oral filling was rated significantly inferior to transduodenal filling in all small bowel segments,whereas filling in the MRI-unit was rated superior to fluoroscopic, mostly due to a mean transport time of 20 min to the MRI-unit. CONCLUSION: No clinically important findings of enteroclysis were missed when using MRI. Therefore, in patients with Crohn's disease, conventional enteroclysis can be replaced by MRI. For optimal bowel distension oral contrast administration is inferior to transduodenal filling, if a larger time delay between filling and the MRI-scan can be avoided.

Administration, Oral↗

PubMed2003

Moving-table MR angiography of the peripheral runoff vessels: comparison of body coil and dedicated phased array coil systems.

OBJECTIVE: The aim of our study was to compare the signal-to-noise ratio and the diagnostic accuracy of moving-table MR angiography of the peripheral arteries with body coil and dedicated phased array coil systems. SUBJECTS AND METHODS: Forty patients were examined with digital subtraction angiography and moving-table MR angiography with a 1.5-T MR imaging system either with a body coil (n = 20) or with a dedicated phased array coil (n = 20). The timing of contrast material was performed with real-time MR fluoroscopy. RESULTS: For the iliac artery, upper leg, and lower leg, the mean values for signal-to-noise ratios were 56, 51, and 17, respectively, for the body coil, and 54, 74, and 64, respectively, for the dedicated phased array coil. For the body coil, sensitivity and specificity in identifying stenosis greater than 50% and occlusions were 100% and 96%, respectively, for the iliac arteries, and 100% and 96%, respectively, for the upper leg. For the dedicated phased array coil, sensitivity and specificity for stenosis greater than 50% and occlusions were 100% and 96%, respectively, for the iliac arteries, and 100% and 98%, respectively, for the upper leg. Sensitivity and specificity were inferior for the body coil (88% and 85%) compared with the dedicated phased array coil (100% and 96%) in the lower leg. A significant difference of the mean values of contrast-to-noise ratio was found before and after subtraction for the dedicated phased array coil and body-coil techniques (Student's t test, p < 0.01). CONCLUSION: In comparison with the body coil, the dedicated peripheral phased array surface coil system improves signal-to-noise ratio for the upper and lower leg and diagnostic accuracy in the lower leg.

Adult↗

PubMed2002

[Surgical therapy of locally advanced and primary inoperable pancreatic carcinoma after neoadjuvant preoperative radiochemotherapy].

INTRODUCTION: So far, surgery represents the only prospect for cure in patients with pancreatic cancer. Most patients, however, present with locally advanced pancreatic cancer at primary diagnosis. Recently, novel therapeutic regimens with preoperative radiochemotherapy have been developed that may improve long-term survival and resectability rates of patients with locally advanced pancreatic cancer. METHODS: This feasibility study evaluates the preliminary results of neoadjuvant therapy with gemcitabine and 5-fluorouracil (5-FU) or cisplatin. Twenty-six patients suffering from locally advanced pancreatic cancer were considered for preoperative radiochemotherapy. They received radiation (45 Gy) and chemotherapy with simultaneous or sequential gemcitabine and 5-FU (n = 15) or gemcitabine and cisplatin (n = 11) administration prior to surgical resection. RESULTS: Mean patient age was 62.4 +/- 2.6 years and 62% (n = 16) were male. The response rate was 69%, and 11 patients underwent curative surgical resection of the pancreatic cancer. Nine Whipple procedures and two complete pancreatectomies were carried out. In five patients a total of eight surgical complications were observed. Median overall survival was 9.8 months after primary cancer diagnosis (mean 12.0 +/- 1.2). During follow-up no local recurrent disease was detected. CONCLUSIONS: Our findings lead us to conclude that preoperative chemoradiation with 45 Gy, gemcitabine and 5-FU or cisplatin is a powerful therapeutic tool in patients with locally advanced non-resectable pancreatic cancer. Major resections, including vascular reconstructions, are nonetheless associated with increased mortality. Preoperative chemoradiation contributes to improved survival in patients with primary non-resectable pancreatic cancer.

Aged↗

PubMed2002

Long-term results after posterior fixation of thoraco-lumbar burst fractures.

Current concepts of treating thoraco-lumbar burst-compression injuries are based on posterior transpedicular fixation techniques which are angular stable. However, the long-term results of this approach are controversial due to inconsistent reports and due to a paucity of data on late outcome. In the present study we analyzed 50 patients retrospectively who had an unstable burst-compression injury at T 11-L 2 (type A 3 according to Magerl) without a neurological deficit. All fractures were stabilized by an internal fixator either with or without transpedicular spongiosa grafting. Patients were treated between 1991 and 1997. Follow-up times ranged from 36 to 103 months. Follow-up examinations collected occupational, subjective and clinical data (activity score, Hannover spine score) and included radiographic measurements. The latter were used to calculate the sagittal index (SI) which measures deformities of the fractured vertebral body, and the sagittal plane kyphosis (SPK) which additionally describes an eventual destruction of the affected intervertebral disc. Compared with the preinjury status, the percentage of subjects who were able to do physical labor was reduced by half at follow-up, and four times as many patients had a permanent disability. Correspondingly, activity scores and Hannover spine scores declined significantly. After the initial surgical correction SI remained stable until follow-up, whereas SPK decreased again towards pre-operative values indicating a progressive deformity of the intervertebral disc space. Clinical results did not correlate with radiographic results, and neither the time until follow-up nor the type of fracture n or the use of transpedicular bone grafting affected clinical or radiographic results significantly.

Adult↗

PubMed2001

Case-oriented computer-based-training in radiology: concept, implementation and evaluation.

BACKGROUND: Providing high-quality clinical cases is important for teaching radiology. We developed, implemented and evaluated a program for a university hospital to support this task. METHODS: The system was built with Intranet technology and connected to the Picture Archiving and Communications System (PACS). It contains cases for every user group from students to attendants and is structured according to the ACR-code (American College of Radiology) 2. Each department member was given an individual account, could gather his teaching cases and put the completed cases into the common database. RESULTS: During 18 months 583 cases containing 4136 images involving all radiological techniques were compiled and 350 cases put into the common case repository. Workflow integration as well as individual interest influenced the personal efforts to participate but an increasing number of cases and minor modifications of the program improved user acceptance continuously. 101 students went through an evaluation which showed a high level of acceptance and a special interest in elaborate documentation. CONCLUSION: Electronic access to reference cases for all department members anytime anywhere is feasible. Critical success factors are workflow integration, reliability, efficient retrieval strategies and incentives for case authoring.

Computer Communication Networks↗

PubMed2001

[Improvement in diagnosis of liver metastases with the multi-detector CT].

The introduction of multidetector computed tomography in clinical routine creates a new dimension of increased spatial and temporal resolution in CT scanning. On the basis of the very short acquisition time, the whole liver can now be scanned within one breathhold. Multidetector-CT allows the examination of the liver with nearly isotropic data sets. This is the prerequisite for the optimal assessment of very small liver lesions in all planes and excellent enhancement of liver lesions in defined organic perfusion phases. The speed of multidetector-CT can either be used to reduce the time to cover a given volume, or to use narrower beam collimation to increase the resolution of details along the z-axis and to reduce volume averaging. We report our clinical experiences in hepatic multidetector-CT examinations and optimized examination protocols in the assessment of hepatic metastases. Multidetector-CT and the use of interactive multiplanar reconstructions improve the detection and characterization of liver metastases. However, new problems in data management may arise from the large amount of data generated by multidetector-CT.

Colorectal Neoplasms↗

PubMed2001

[Radiofrequency ablation of liver metastases. Technique and initial results].

Primary and secondary malignant hepatic tumors are the most common tumors with a much more higher incidence of hepatic metastases. Chemotherapy and radiation therapy are in general ineffective. Therefore, surgical resection is considered the method of choice in the treatment of malignant hepatic lesions. Due to systemic disease, general medical or procedure-related reasons hindering surgery, only 25 to 45% of the patients with metastatic disease of the liver are suitable for a curative surgical therapy. In resectable lesions thermoablative methods can offer an alternative to the surgical therapy. The most experience exists in radiofrequency ablation techniques. Technique, indications, contraindications, and limitations of the radiofrequency ablation will be discussed together with a presentation of own cases and a review of the literature. In 37 patients the primary technical success rate of the ablation was 97.3% (72 of 74 lesions). In 4 cases a hematoma of the liver capsule occurred. One of these had to be treated interventionally. During the limited follow-up period of 9 months no local recurrency was seen, however 4 patients developed new hepatic metastases. Beside differences in practicability it is not yet clarified if there are differences in the therapeutic efficacy of the different thermoablation methods. Nevertheless, the results of the ablation therapy may parallel the results of the surgical resection. Interstitial thermotherapy can provide a valuable contribution to local tumor control. However, the final significance of the thermoablation techniques within oncological therapy regimens has to be evaluated in further multidisciplinary studies.

Adult↗

PubMed2001

Acute ischemia of the upper extremity: long-term results following thrombembolectomy with the Fogarty catheter.

OBJECTIVE: In 1962, the procedure of arterial thrombembolectomy with the Fogarty catheter was established. Numerous studies have been published studying thrombembolectomies of the lower extremities. Limited information, however, is available following thrombembolectomy of the upper extremity after arterial occlusion. The aim of the present study, therefore, was to determine long-term results (3-5 years after thrombembolectomy) following thrombembolectomy of the upper extremity with the Fogarty catheter in a large retrospective clinical study. DESIGN: In the present study, 251 patients were encountered. Over a period of 20 years, 283 thrombembolectomies with the Fogarty catheter were performed on the upper extremity at the surgical department of the University of Munich. MAIN OUTCOME MEASUREMENTS: The appearance of local and general complications in the postoperative phase, as well as long-term results, were evaluated. RESULTS: The results indicate that general complications - i.e., cardiac insufficiency, cerebral ischemia, etc. - occurred in 18 patients (7.2%). Local complications - i.e., wound infection, persistence of ischemia, or hematoma - were evident in 51 patients (20.3%). Re-occlusion following thrombembolectomy was found in 21 patients (8.8%). The affected extremity had to be amputated in five cases (2.0%), and 14 patients (5.6%) died during the postoperative phase. As a result of multimorbidity of the patients and average age at the time of surgery (73 years), 40% of the patients had died before the date of examination. Nonetheless, 111 patients of the 117 living patients showed no complaints or minor coldness and pain following heavy exercise. CONCLUSIONS: The results of the present study indicate that, in most cases, thrombembolectomy with the Fogarty catheter represents a successful surgical method for the acute treatment of arterial occlusion of the upper extremity.

Adult↗

PubMed2001

Value of systematic mediastinal lymph node dissection during pulmonary metastasectomy.

BACKGROUND: Systematic mediastinal lymph node dissection is the accepted standard when curative resection of bronchial carcinoma is performed. However, mediastinal lymph node dissection is not routinely performed with pulmonary metastasectomy, in which only enlarged or suspicious lymph nodes are removed. The incidence of malignant infiltration of mediastinal lymph nodes in patients with pulmonary metastases is not known. METHODS: Sixty-three patients who underwent 71 resections through a thoracotomy for pulmonary metastases of different primary tumors were studied prospectively. Selected patients showed no evidence of tumor progression or extrathoracic metastases and pulmonary metastasectomy was planned with curative intent. All patients underwent preoperative helical computed tomography (CT) scanning. Only patients with no evidence of suspicious mediastinal lymph nodes on the CT scan (less than 1 cm in the short axis) were included in this study. A mediastinal lymph node dissection was performed routinely with metastasectomy. RESULTS: In 9 patients (14.3%) at least one mediastinal lymph node revealed malignant cells in accordance with the resected metastases. When compared with the preoperative CT scan, additional pulmonary metastases were detected in 16.9% of performed operations. There was a trend toward an improved survival rate in patients without involvement of the mediastinal lymph nodes. The number of pulmonary metastases had no influence on survival. CONCLUSIONS: On a patient-by-patient basis, the frequency of misdiagnosed mediastinal lymph node metastases is about the same as compared with non-small cell bronchial carcinomas. Systematic mediastinal lymph node dissection reveals a significant number of patients, who otherwise are assumed free of residual tumor. The knowledge of metastases to mediastinal lymph nodes after complete resection of pulmonary metastases could influence the decision for adjuvant therapy in selected cases.

Adult↗

PubMed2001

[Evaluation of an electromagnetic virtual target system (CT-guide) for CT-guided interventions].

PURPOSE: Evaluation of the accuracy of a new electromagnetic target system for interventional CT-guided procedures with virtual navigation in a previously acquired helical CT. MATERIAL AND METHODS: The new target system CT-Guide 1010 (Ultraguide, Tirat Hacarmel, Israel) for CT-guided interventions was adapted to the video signal of the Somatom Plus 4 and Volume Zoom (Siemens, Erlangen, Germany). A helical CT-dataset including skin-based sensor cubes was transferred to the integrated navigation system inside the scanner room. 50 image-guided interventions and biopsies were performed outside the gantry using virtual navigation to reach the lesion. The accuracy of the procedures was evaluated using documentation of the needle tip with CT-fluoroscopy, results of histology, and follow-up. RESULTS: The deviation between planned and documented needle tip was 2.2 +/- 2.1 mm in 50 procedures. Time between the end of planning-CT and needle positioning using the system was 13 minutes. There were no complications due to the use of the system. CONCLUSION: The CT-Guide allows for virtual real-time navigation with high accuracy. Advantages are the free needle angulation without gantry tilt, use of optimal CT perfusion phase for virtual navigation, and reduction of radiation exposure to the patient and interventionalist.

Adult↗

PubMed2001

New contrast agents for imaging the liver.

The contrast agents suited for hepatic imaging can be divided into nonspecific, extracellular space- (ECS) directed, reticuloendothelial system- (RES) selective, and hepatocyte-selective compounds. There is a wide variation in regard to biodistribution, pharmacokinetics, contrast behavior, and tissue specificity. The ECS contrast agents provide information on vascularization and perfusion similar to that of X-ray contrast agents. The RES- and hepatocyte-specific contrast agents offer more "functional" information that may enhance tissue characterization; however, the biology of the different hepatocellular and nonhepatocellular tumors is limiting the diagnostic efficacy of the tissue-specific compounds in many respects.

Animals↗

PubMed2000

[MR angiography of the supraaortic vessels].

PURPOSE: To compare high resolution contrast-enhanced MR angiography (MRA) and digital subtraction angiography (DSA) in the assessment of supraaortic vessel stenosis. METHODS: 14 patients with suspicion of cerebrovascular disease or upper limb ischemia underwent selective DSA and high resolution contrast enhanced MRA employing a new Panoramic-Array coil. Stenosis assessment in comparison to DSA followed NASCET criteria. Additionally signal-/noise ratios (SNR) were evaluated to assess contrast enhancement. RESULTS: Diagnostic image quality was achieved in all patients. Sensitivity and specificity for assessing high-grade stenosis of the supraaortic vessels were 100% and 96% respectively. In the assessment of high-grade common or internal carotid artery stenosis sensitivity and specificity was 100%. CONCLUSION: High resolution contrast enhanced supraaortic MRA combined with new coil systems allow for a reliable assessment of stenoses along the whole vessel course including the aortic arch. Previous stent procedures limit its use in postinterventional follow-up.

Adult↗

PubMed2000

[Stenoses and occlusions of the supraaortic vessels--the interdisciplinary interventional treatment of patients with an increased surgical risk].

PURPOSE: The value of elective PTA in stenoses of the supraaortic vessels and especially of the carotid artery is still under discussion. Stenoses after surgical and/or radiation therapy and a high cardio-vascular risk for a surgical procedure, however, justify minimal-invasive techniques. MATERIAL AND METHODS: In 31 patients with 24 symptomatic and 7 asymptomatic stenoses of the supraaortic arteries (3 Acc, 19 Aci, 5 Ascl, 4 Tr.brc, 2 Aax) minimal-invasive angioplasty and stent-placement was performed. The rationale for the interventional procedure was an elevated medical or technical risk of the respective surgical procedure. All procedures were performed using a coaxial technique with a guiding catheter. An open vascular access was necessary in 7 cases due to an unfavorable anatomical situation. RESULTS: The technical success rate was 100%. Peri-interventionally, a TIA occurred in 2 patients (1 spontaneous relieve, 1 complete remission after rt-PA lysis therapy). During the mean follow-up period of 13 months 3 patients died due to non-cerebrovascular reasons. In 2 patients a moderate restenosis, in 1 a high-grade stenosis, and in 1 and complete occlusion occurred without symptoms. After one year of follow-up, all treated stenoses were patent with a restenosis rate of 10.7% without further neurological symptoms. CONCLUSION: Interventional angioplasty with stent-placement of the supraaortic arteries is a safe and effective alternative in patients are at high risk for classical surgical procedures.

Adult↗

PubMed2000

Effect of superparamagnetic iron oxide on bone marrow.

The goal of this study was to compare the effects of SPIO particles on the signal intensity of the bone marrow of the vertebra spine in patients with and without liver cirrhosis. Forty-eight patients with normal liver tissue and 56 patients with liver cirrhosis were examined before and after intravenous SPIO administration, using a 1.5-T system (Magnetom Vision, Siemens, Erlangen, Germany) with a semiflexible cp-array coil. Three different pulse sequences were applied: a T1-weighted gradient-echo sequence, a T2-weighted fast spin-echo sequence with spectral fat suppression and a T2*-weighted gradient-echo sequence. The signal-to-noise ratio (SNR) of the liver, vertebra bone and paraspinal muscle were obtained. The SNR value change in each patient group and the SNR value difference between the two groups were evaluated. For assessment of statistical significance, Student's t-test with a level of p < 0.05 was applied. No significant differences in the SNR values of the liver and bone marrow between the two groups could be seen with any of the three sequences precontrast. Using the T1-weighted gradient-echo sequence in the noncirrhotic liver group, pre- and postcontrast comparisons of the SNR values of the liver and bone marrow indicated a decrease of approximately -44.3% (p = 0.02) and increase of approximately 15.3% (p = 0.04), respectively. No significant change was seen in the cirrhotic liver group. With the T2-weighted fast spin-echo sequence, a significant decrease of the SNR value of the liver and the bone marrow in both groups was seen. With the T2*-weighted gradient-echo sequence, the signal intensity decrease of the normal liver tissue was approximately -65.6% (p = 0.00), in cirrhotic liver tissue the decrease was -29.9% (p = 0.02). The SNR values of the bone marrow showed a decrease of -27.8% (p = 0.04) in the noncirrhotic liver group, whereas in the cirrhotic liver group it was only -11.3% and statistically not significant. The effect of SPIO particles on the liver and bone marrow is significantly less in patients with liver cirrhosis.

Adult↗

PubMed2000

Signal changes in liver and spleen after Endorem administration in patients with and without liver cirrhosis.

The goal of this study was compare the effect of Endorem on the signal intensity of the spleen in patients with normal liver tissue and in patients with liver cirrhosis. Thirty patients with normal liver tissue and 47 with liver cirrhosis were examined before and after i.v. Endorem administration. The patients were examined with a 1.5-T magnet system (Magnetom Vision) using a semiflexible cp-array coil. Three different pulse sequences were used: a T1-weighted gradient-echo sequence, a T2-weighted fast spin-echo sequence with spectral fat suppression, and a T2*-weighted gradient-echo sequence. The signal-to-noise ratios (SNRs) of two areas of the liver and spleen were determined. The mean SNRs of the liver and spleen in patients with and without liver cirrhosis were compared. For assessment of statistical significance, the t-test at a level of P < 0.05 was applied. After i.v. administration of Endorem, no differences were seen with the T1-weighted gradient-echo sequence for the liver and spleen and, with the T2-weighted fast spin-echo sequence, no differences were found for the spleen. Significant differences between both groups were seen for the liver with the T2-weighted fast spin-echo sequence. The SNR in the noncirrhotic liver group was 57.4% lower than the SNR in the cirrhotic liver group. With the T2*-weighted gradient-echo sequence, the SNRs of the liver and spleen in the noncirrhotic liver group, compared with the cirrhotic liver group, were 126.8% and 45.6% less, respectively. The effect of Endorem on the liver in patients with Child C-stage liver cirrhosis was 32.1% less than in patients with Child B-stage liver cirrhosis. Likewise, the Endorem effect on the spleen was 27.1% less in patients with Child C-stage compared with Child B-stage liver cirrhosis. Hepatic and splenic uptake of Endorem is significantly decreased in patients with liver cirrhosis.

Adult↗

PubMed2000

Impact of virtual reality imaging on hepatic liver tumor resection: calculation of risk.

The risk involved in partial liver resections depends mainly on tumor localization, invasion of central vascular structures, and parenchymal function. The imaging techniques available today (computed tomography, magnetic resonance imaging) allow us to detect precisely the extent of tumor invasion and their relationship to central vessels. The various three-dimensional reconstruction techniques are helpful with regard to a virtual planning of liver resections. The calculation of remaining liver volumes subsequent to partial hepatectomies are considered to be an essential predictive parameter in terms for the development of postoperative liver failure. In a retrospective and a later consecutive, prospective clinical study we analyzed the postoperative risk in a series of 570 patients. In an univariate analysis 13 of 31 parameters showed significant values. In multivariate analysis only three parameters (partial hepatic resection rate, PHRR), gamma-glutamyltranspeptidase, and prothrombin activity) were independent parameters for predicting liver failure, generating the most significant values for the PHRR. In our experience the most comfortable and precise technique for evaluating PHRR is the b-spline technique.

Female↗

PubMed2000

[Effects of biphasic spiral CT, conventional and iron oxide enhanced MRI on therapy and therapy costs in patients with focal liver lesions].

PURPOSE: Evaluation of the diagnostic efficacy and cost-benefit of contrast enhanced CT (CT) and MRI pre- and post-SPIO-particles in focal hepatic disease with consideration of therapeutic outcome. METHODS: In 52 patients with the suspicion of primary or secondary hepatic malignancy, biphasic spiral CT and breath-hold gradient-echo T1- and fast spin-echo T2-weighted MRI pre- and post-iron oxide administration (1.5 T, body-phased-array coil) were compared. The number of hepatic lesions and the related diagnoses resulting from each imaging modality were recorded and statistically correlated to the final diagnoses established by biopsy/OP (34/52), long term follow-up of 12 months (18/52), and a consensus reading of all imaging modalities considering all clinical imaging information. The most likely induced therapy resulting from each imaging test was correlated to the final therapy. Based on data from the hospitals accountants, the therapy-related costs were estimated without hospitalization costs. RESULTS: In 34/52 (65.4%) of the cases the correct diagnosis was primarily stated by CT (sensitivity [se.] 85.2%, specificity [sp.] 44.0%). In additional 10/52 of the cases unenhanced MRI (se. 91.4%, sp. 75.0%) enabled correct diagnoses, and in another 6 cases the diagnosis was established only by SPIO-MRI (se. 100%, sp. 86.7%). Considering the possible therapeutic recommendation arising from each modality, CT would have induced needles therapy costs of 191,042 DM, unenhanced MRI of 171,035 DM, and SPIO-MRI of 7,311 DM. In comparison to the real therapy costs of 221,873 DM, this would have corresponded to an unnecessary increase of therapy costs of 86.1%, 77.1%, and 3.3%, respectively. In two cases (1 hemangioma, 1 regenerative nodule) all modalities failed, causing unnecessary surgery in one patient. DISCUSSION: In this problem-oriented scenario unenhanced and SPIO-enhanced MRI proved to be superior to CT regarding diagnostic efficacy. The cost-benefit resulted mainly due to preserving patients from unnecessary surgical procedures.

Adenoma, Liver Cell↗

PubMed2000

Segmental and subsegmental pulmonary arteries: evaluation with electron-beam versus spiral CT.

PURPOSE: To compare contrast agent-enhanced spiral and electron-beam computed tomography (CT) for the analysis of segmental and subsegmental pulmonary arteries. MATERIALS AND METHODS: CT angiography of the pulmonary arteries was performed in 56 patients to rule out pulmonary embolism. Electron-beam CT was performed in 28 patients. The other 28 patients underwent spiral CT with comparable scanning protocols. The depiction of segmental and subsegmental arteries was analyzed by three independent readers. The contrast enhancement in the main pulmonary artery was measured in each patient. RESULTS: Analysis was performed in 1,120 segmental and 2, 240 subsegmental arteries. One segmental (RA7, P =.010) and two subsegmental (LA7b, P =.029; RA6a+b, P =.038) arteries in paracardiac and basal segments of the lung were depicted significantly better with electron-beam CT. There was no statistically significant difference between electron-beam and spiral CT in the total number of analyzable peripheral arteries depicted. The mean contrast enhancement in the main pulmonary artery was 362 HU in electron-beam CT studies versus 248 HU in spiral CT studies. CONCLUSION: Detailed visualization of peripheral pulmonary arteries is well within the scope of advanced CT techniques. Electron-beam CT has minor advantages in analyzing paracardiac arteries, probably because of reduction of motion artifacts and higher contrast enhancement. Further studies are needed to establish whether electron-beam CT allows a more confident diagnosis of emboli in these vessels.

Adult↗