Advantages and Limitations of Focal Liver Lesion Assessment with Ultrasound Contrast Agents: Comments on the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) Guidelines.

Contrast-enhanced ultrasound (CEUS) represents a significant breakthrough in sonography. Due to US contrast agents (UCAs) and contrast-specific techniques, sonography offers the potential to show enhancement of liver lesions in a similar way as contrast-enhanced cross-sectional imaging techniques. The real-time assessment of liver perfusion throughout the vascular phases, without any risk of nephrotoxicity, represents one of the major advantages that this technique offers. CEUS has led to a dramatic improvement in the diagnostic accuracy of US and subsequently has been included in current guidelines as an important step in the diagnostic workup of focal liver lesions (FLLs), resulting in a better patient management and cost-effective therapy. The purpose of this review was to provide a detailed description of contrast agents used in different cross-sectional imaging procedures for the study of FLLs, focusing on characteristics, indications and advantages of UCAs in clinical practice.

Resectability of pancreatic adenocarcinoma: assessment using multidetector-row computed tomography with multiplanar reformations.

The purpose was to assess capabilities of the multidetector-row computed tomography (MDCT) with multiplanar reformations (MPR) for predicting of pancreatic adenocarcinoma resectability. Forty-eight patients deemed to have resectable pancreatic adenocarcinoma after assessment using biphasic MDCT with MPRs underwent surgery for potential tumor resection. Imaging findings were retrospectively evaluated for tumor resectability and correlated with surgical and pathological results. Curative resection was successful in 44 of 48 patients. The positive predictive value for tumor resectability made up 91% with four false-negative results. The reasons for unresectability were venous involvement (1), small liver metastases (2) and peritoneal involvement associated with small metastases to lymph nodes (1). MDCT yielded a negative predictive value of 99% (286 of 288 vessels) for detection of vascular invasion. Our results indicate the tendency towards improved prediction of resectability using MDCT compared to single-detector CT.

Diagnostic accuracy of noninvasive coronary angiography in patients after bypass surgery using 64-slice spiral computed tomography with 330-ms gantry rotation.

BACKGROUND: Multidetector computed tomographic angiography (MDCT) has been shown to allow detection of coronary artery bypass graft (CABG) occlusions and stenoses. However, the assessment of native coronary arteries in addition to CABG has thus far not been sufficiently validated. METHODS AND RESULTS: Fifty patients with a total of 138 CABG (34 mammary grafts, 3 radial grafts, 101 venous grafts) were investigated by MDCT (0.6-mm collimation, 32 detector rows, 2 focal points, 330-ms rotation) 9 to 252 months (mean, 106 months) after surgery. CABG and all native coronary arteries with a diameter of > 1.5 mm were evaluated for the presence of significant stenoses (> or = 50% diameter reduction). Results were compared with quantitative coronary angiography. By MDCT, all CABG were evaluable and were correctly classified as occluded (n=38) or patent (n=100). Sensitivity for stenosis detection in patent grafts was 100% (16/16) with a specificity of 94% (79/84). For the per-segment evaluation of native coronary arteries and distal runoff vessels, sensitivity in evaluable segments (91%) was 86% (87/101) with a specificity of 76% (354/465). If evaluation was restricted to nongrafted arteries and distal runoff vessels, sensitivity was 86% (38/44) with a specificity of 90% (302/334). On a per-patient basis, classifying patients with at least 1 detected stenosis in a CABG, a distal runoff vessel, or a nongrafted artery or with at least 1 unevaluable segment as "positive," MDCT yielded a sensitivity of 97% (35/36) and specificity of 86% (12/14). CONCLUSIONS: We found that 64-slice MDCT permits the evaluation of bypass grafts and the assessment of the native coronary arteries for the presence of stenosis.

Endorectal fusion imaging: A description of a new technique.

BACKGROUND: Fusion imaging is an accepted method in abdominal imaging allowing a simultaneous display of reference imaging with a live ultrasound (US) investigation. For prostate cancer, promising results have been published for endorectal US (ERUS)-guided biopsy of suspicious lesions in magnetic resonance imaging (MRI). To our knowledge, no other indication for the fusion of ERUS with MRI has been reported so far. METHODS: We report on three patients scheduled for ERUS due to anorectal fistulae after treatment (n = 2) or rectal carcinoma (n = 1), which were scheduled for real-time virtual onography (RVS), a method for the fusion of MRI imaging with US. RESULTS: In all patients, RVS was successful. The course of the fistulae could be defined and the success of the treatment could be confirmed. In the patient with rectal carcinoma, the lymph nodes suspicious in MRI could be identified. CONCLUSIONS: MRI/ERUS fusion has the potential for follow-up of anorectal fistulae and abscesses, and staging of anal and rectal tumors.

[Atypical Lipomatous Tumour of the Hand]. / Atypischer lipomatöser Tumor der Hand.

Atypical lipomatous tumours (ALT) are rare semi-malignant adipose tissue tumours with the potential to transform into sarcomas. They may occur throughout the body, although the hands are very rarely involved. We present the case of a 49-year-old man with a lipomatous tumour measuring 8×4 cm at the dorsum of the right thumb. MRI demonstrated an inhomogeneous signal after contrast medium application. The tumour was excised in its entirety. Since histology confirmed the diagnosis of an ALT, the thumb was irradiated. The patient remained free of recurrence. An ALT has to be suspected if a lipomatous tumour is very large. We recommend an MRI prior to surgery in tumours larger than 5 cm. Excision should follow oncologic principles.

Efficacy and tolerability of pegylated IFN-alpha in patients with neuroendocrine gastroenteropancreatic carcinomas.

Interferon-alpha (IFN-alpha) is well established in the treatment of neuroendocrine carcinomas (NEC). Treatment is accompanied by fatigue and flu-like symptoms. In patients with chronic hepatitis C, pegylated IFN (PEGIFN) leads to improved antiviral efficacy and good tolerability. Our aim was to assess the efficacy and tolerability of PEG-IFN on the management of patients with well-differentiated NEC of the gastroenteropancreatic system. In 17 patients, the effect of PEG-IFN-alpha2b was studied. After first-line octreotide treatment, IFN-alpha was added at the time of tumor progression. Six patients were switched from conventional IFN-alpha, and 11 patients were IFN naive. Inhibition of tumor growth, including stabilization of disease, occurred in 13 of 17 patients, and biochemical and symptomatic responses were seen in 7 of 10 patients with functionally active tumors. Tolerability of PEG-IFN-alpha2b was much better than that of IFN-alpha. Fatigue occurred in 59% of all patients but was mild in severity. Eleven of thirteen patients who had a benefit remained on therapy for a median time of 20 months (range 6-30 months). PEG-IFN-alpha2b provides symptomatic and antiproliferative efficacy in patients with NEC. Better tolerability of PEG-IFN-alpha2b improved patients' compliance, justifying its use in patients who do not tolerate conventional IFN-alpha treatment.

Usefulness of multidetector row spiral computed tomography with 64- x 0.6-mm collimation and 330-ms rotation for the noninvasive detection of significant coronary artery stenoses.

Eighty-four patients with suspected coronary artery disease were studied to determine the accuracy of noninvasive coronary angiography using a multidetector computed tomographic scanner with 64- x 0.6-mm collimation and 330-ms gantry rotation. All coronary artery segments with a diameter >1.5 mm were assessed with respect to stenoses >50% decreased diameter. Results were compared with quantitative coronary angiographic findings. After exclusion of unevaluable coronary segments (4%), multidetector computed tomography demonstrated a sensitivity of 93%, a specificity of 97%, and a negative predictive value of 100% in a per-segment analysis. In a per-artery analysis, 15 of 336 arteries (4%) were unevaluable. Sensitivity and specificity in evaluable arteries were 95% and 93%, respectively. In a per-patient analysis (81 of 84 patients included), sensitivity and specificity were 96% and 91%, respectively.

Large topographic variability of upper abdominal lymphatics and the consequences for radiation treatment planning.

BACKGROUND AND PURPOSE: Inclusion of regional lymph nodes usually is indicated when treating upper gastrointestinal malignancies. Lymphatics follow the large vessels of this region. Vascular variability with consequences for planning treatment volume (PTV) was studied. MATERIALS AND METHODS: Upper abdominal metric relationship of the vascular origins was analysed in CT scans in 104 patients to estimate its influence on PTV variability. PTV volumes were calculated based on these. Additionally, the PTV size of 3D plans of 34 patients with pancreatic adenocarcinoma (PDAC) was analysed depending on different PTV definitions. RESULTS: Vascular origin varied most for the inferior mesenteric artery (IMA) with substantial PTV size differences. Volumetric variability was analysed for PDAC (IMA versus renal hilum as caudal margin). Additional PTV for IMA was < 100 cc (median) but ranged up to 350 cc in CT (100-199 ml in 14/34 and > 200 ml in 3/34 patients). Data from treatment planning confirmed this observation. CONCLUSIONS: Considerable vascular and lymphatic variability obliges to base PTV on the individual vascular anatomy. For most patients the caudal PTV margin for PDAC can safely be set at the IMA. But PTV should be restricted when the additional volume would lead to a significant increase to avoid haematotoxicity from concomitant gemcitabine which is proportional with PTV size. The risk of kidney toxicity is also subject to PTV expansion in the caudal direction.

Visualization of coronary artery anomalies by contrast-enhanced multi-detector row spiral computed tomography.

BACKGROUND: We investigated the potential of 16-slice multi-detector row spiral CT (MDCT) with retrospective ECG-gating for evaluation of coronary artery anomalies. METHODS: A total of 35 patients (23 men, 12 women, 19-81 years) in whom anomalous coronary arteries had been detected by invasive coronary angiography underwent MDCT (Sensation 16, Siemens, Germany). During one breathhold, a contrast-enhanced (90 ml, 5 ml/s) volume data set of the heart was acquired (16x0.75mm collimation, gantry rotation 375 ms). Images were reconstructed with a slice thickness of 1.0 mm in 0.5-mm intervals using retrospective ECG-gated reconstruction. The 35 data sets and 80 data sets of patients with angiographically normal coronary anatomy were analysed in random order concerning the origin and course of the coronary arteries. The results were compared to invasive coronary angiography. RESULTS: All patients with coronary artery anomalies and all controls with normal coronary anatomy were identified by MDCT. In addition, the origins and course concerning their anatomical relationship to adjacent cardiac structures were visualized in all patients, including right-sided origin of the left main (n=10), left anterior descending coronary artery (n=4) or left circumflex coronary artery (n=10); left-sided origin of the right coronary artery (n=6); four coronary fistula to the pulmonary artery (two from the left anterior descending, one from the right coronary artery, one from the left main), and one fistula from the circumflex coronary artery to the left atrium CONCLUSIONS: The study demonstrates that MDCT is a reliable noninvasive technique to identify and define anomalous coronary arteries and their course.

Coronary artery bypass graft (CABG) patency: assessment with high-resolution submillimeter 16-slice multidetector-row computed tomography (MDCT) versus coronary angiography.

PURPOSE: To investigate the ability of 16-slice multidetector-row computed tomography (MDCT) to visualize coronary artery bypass graft (CABG) patency and to detect bypass stenoses. MATERIALS AND METHODS: Thirty-two patients with 94 grafts (20 mammary artery grafts, 74 venous grafts) were investigated by 16-slice MDCT using a scan protocol with 12 x 0.75 mm slice collimation (pitch 0.3), 420 ms rotation time and simultaneous electrocardiogram (ECG)-registration. One hundred milliliters iodinated contrast agent were injected with a delay according to the individually determined contrast agent transit time. Patients with heart rates above 60 bpm received oral beta-blockade. Cross-sectional images with a slice width of 1.0 mm (0.5 mm increment) were reconstructed using an ECG-gated half-scan reconstruction or a multisegment reconstruction algorithm depending on the heart rate. Bypass grafts were evaluated concerning patency and presence of stenoses > or = 50% diameter reduction on cross-sectional images, multiplanar reformations and maximum intensity projections by two independent observers. Results were compared to coronary bypass angiography. RESULTS: Sixteen-slice MDCT results were compared to those of invasive coronary angiography concerning absence or presence of bypass graft occlusion or relevant stenosis > or = 50% lumen reduction. Coronary CT angiography (CTA) permitted detection of bypass occlusion with 100% sensitivity (28/28) and 98% specificity (64/65). Seventy-eight percent (observer 1) and 84% (observer 2) of all patent grafts were found to be evaluable concerning presence or absence of stenosis. In 34 of 40 (observer 1) and 38 of 43 (observer 2) bypass grafts, high-grade stenoses were correctly ruled out (specificity 85% versus 88%, sensitivity 80% and 82%). Yet, if all patients with either unevaluable grafts/graft anastomosis or relevant graft stenosis were excluded, only 8/32 patients (25%) had fully diagnostic "negative" graft-CTA. According to Kappa statistics, agreement between the observers was 1.0 and 0.93 concerning occlusion and relevant stenosis, respectively. CONCLUSION: Sixteen-slice coronary CTA with sub-millimeter spatial resolution and premedication with oral beta-blockade permits non-invasive assessment of coronary artery bypass grafts with decreasing numbers of unevaluable graft segments. However, patient-based analysis reveals that only a relatively small number of patients ("negative" and completely evaluable graft-CTA) truly profits from noninvasive work-up and could be spared invasive angiography.

Detection of coronary artery stenoses with thin-slice multi-detector row spiral computed tomography and multiplanar reconstruction.

BACKGROUND: We analyzed the accuracy of multi-detector row spiral computed tomography (MDCT) using a 16-slice CT scanner with improved spatial and temporal resolution, as well as routine premedication with beta-blockers for detection of coronary stenoses. METHODS AND RESULTS: Seventy-seven patients with suspected coronary disease were studied by MDCT (12x0.75-mm cross-sections, 420 ms rotation, 100 mL contrast agent IV at 5 mL/s). Patients with a heart rate above 60/min received 50 mg atenolol before the scan. In axial MDCT images and multiplanar reconstructions, all coronary arteries and side branches with a diameter of 1.5 mm or more were assessed for the presence of stenoses exceeding 50% diameter reduction. In comparison to invasive coronary angiography, MDCT correctly classified 35 of 41 patients (85%) as having at least 1 coronary stenosis and correctly detected 57 of 78 coronary lesions (73%). After excluding 38 of 308 coronary arteries (left main, left anterior descending, left circumflex, and right coronary artery in 77 patients) classified as unevaluable by MDCT (12%), 57 of 62 lesions were detected, and absence of stenosis was correctly identified in 194 of 208 arteries (sensitivity: 92%; specificity: 93%; accuracy: 93%; positive and negative predictive values: 79% and 97%). CONCLUSIONS: MDCT coronary angiography with improved spatial resolution and premedication with oral beta-blockade permits detection of coronary artery stenoses with high accuracy and a low rate of unevaluable arteries.

Detection of calcified and noncalcified coronary atherosclerotic plaque by contrast-enhanced, submillimeter multidetector spiral computed tomography: a segment-based comparison with intravascular ultrasound.

BACKGROUND: We investigated the ability of multidetector spiral computed tomography (MDCT) to detect atherosclerotic plaque in nonstenotic coronary arteries. METHODS AND RESULTS: In 22 patients without significant coronary stenoses, contrast-enhanced MDCT (0.75-mm collimation, 420-ms rotation) and intravascular ultrasound (IVUS) of one coronary artery were performed. A total of 83 coronary segments were imaged by IVUS (left main, 19; left anterior descending, 51; left circumflex, 4; right coronary, 9). MDCT data sets were evaluated for the presence and volume of plaque in the coronary artery segments. Results were compared with IVUS in a blinded fashion. For the detection of segments with any plaque, MDCT had a sensitivity of 82% (41 of 50) and specificity of 88% (29 of 33). For calcified plaque, sensitivity was 94% (33 of 36) and specificity 94% (45 of 47). Coronary segments containing noncalcified plaque were detected with a sensitivity of 78% (35 of 45) and specificity of 87% (33 of 38), but presence of exclusively noncalcified plaque was detected with only 53% sensitivity (8 of 15). If analysis was limited to the 41 proximal segments (segments 1, 5, 6, and 11 according to American Heart Association classification), sensitivity and specificity were 92% and 88% for any plaque, 95% and 91% for calcified plaque, and 91% and 89% for noncalcified plaque. MDCT substantially underestimated plaque volume per segment as compared with IVUS (24+/-35 mm3 versus 43+/-60 mm3, P<0.001). CONCLUSIONS: The results indicate the potential of MDCT to detect coronary atherosclerotic plaque in patients without significant coronary stenoses. However, further improvements in image quality will be necessary to achieve reliable assessment, especially of noncalcified plaque throughout the coronary tree.

Assessment of coronary remodeling in stenotic and nonstenotic coronary atherosclerotic lesions by multidetector spiral computed tomography.

OBJECTIVES: This study was designed to investigate whether contrast-enhanced multidetector spiral CT (MDCT) permits assessment of remodeling in coronary atherosclerotic lesions. BACKGROUND: With sufficient image quality, MDCT permits noninvasive visualization of the coronary arteries, but its ability to assess remodeling has not been evaluated. METHODS: Out of 102 patients in whom MDCT (16-slice scanner, intravenous contrast, 0.75-mm collimation, 420 ms rotation) was performed before invasive coronary angiography, 44 patients with high-quality MDCT data sets showing atherosclerotic plaque in a proximal coronary artery segment were chosen for evaluation. In multiplanar reconstructions orthogonal to the coronary artery, the cross-sectional vessel area was measured for the respective lesion and for a reference segment proximal to the lesion. The "Remodeling Index" was calculated by dividing the vessel area in the lesion by the reference segment. Results were correlated to the presence of stenosis (>50% diameter reduction) in invasive angiography. In a subset of 13 patients, MDCT measurements were verified by IVUS. RESULTS: Reference vessel area was not significantly different between nonstenotic versus stenotic lesions (20 +/- 8 mm(2), n = 23 vs. 22 +/- 8 mm(2), n = 21). The mean Remodeling Index was significantly higher in nonstenotic than in stenotic lesions (1.3 +/- 0.2 vs. 1.0 +/- 0.2, p < 0.001). In five stenotic lesions, "negative remodeling" (Remodeling Index < or = 0.95) was observed. Cross-sectional vessel areas and Remodeling Indices measured by MDCT correlated closely to IVUS (r(2) = 0.77 and r(2) = 0.82, respectively). CONCLUSIONS: Multidetector spiral CT may permit assessment of remodeling of coronary atherosclerotic lesions in selected data sets of sufficient quality.

Definition of elective lymphatic target volume in ductal carcinoma of the pancreatic head based on histopathologic analysis.

PURPOSE: In chemoradiation for pancreatic carcinoma three-dimensional target volume definitions could maximize tolerability and therapeutic effect at the same time because toxicity correlates with treatment volume. We aimed to define guidelines for elective treatment of nodal areas based on pathologic nodal involvement to optimize treatment volume for this tumor. METHODS AND MATERIALS: Pathologic patterns of regional nodal spread in 175 patients who underwent primary pancreatoduodenectomy with > or =10 assessed nodes and literature data on para-aortic spread were the base of the definition of the target volume. Significant correlations between spread to lymphatic areas and tumor characteristics were determined using Fisher's exact test. Computed tomography scans and a Pinnacle3 (Philips, Best, The Netherlands) system were used for treatment planning. RESULTS: Among 175 resected tumors without pretreatment, 76% had regional nodal metastasis and 22% had spread to distant nodes. High-risk lymphatic areas were identified and selected for elective treatment. A standardized planning procedure was derived and tested under treatment conditions. CONCLUSIONS: Histopathologic data allowed us to develop recommendations for standardized treatment planning for ductal carcinoma of the pancreatic head. These are proposed for quality assurance in multicenter studies and routine use.

Doxorubicin and streptozotocin after failed biotherapy of neuroendocrine tumors.

BACKGROUND: Well-differentiated neuroendocrine tumors are treated primarily with somatostatin analogs and interferon-alpha. It is not clear what therapy should be applied after failed biotherapy. Our aim was to establish whether patients whose tumors rapidly progress under biotherapy may benefit from chemotherapy. PATIENTS AND METHODS: In 10 patients with metastatic neuroendocrine tumors (4 foregut, 3 midgut, 1 retroperitoneal, and 2 of unknown origin) streptozotocin and doxorubicin were used as second-line or third-line therapy. Tumor response was assessed by computed tomography of the abdomen and thorax and measurement of tumor secretion products (serum chromogranin A, urinary 5-hydroxyindoleacetic acid). RESULTS: Three patients showed a radiological response over a mean time of 30 mo (range: 7-67 mo). Median survival after initiation of chemotherapy was 50 mo in patients with a response and 8 mo in non-responders. Three patients developed major side effects (nephrotoxicity, diabetes, and encephalopathy). CONCLUSION: Streptozotocin and doxorubicin produce poor response rates in patients with progressive neuroendocrine tumors after failed biotherapy, but may prolong life in those patients who show a tumor response.

[Diagnostic imaging with a 64-slice computed tomography scanner--the first year in clinical routine]. / 64-Schicht-Spiral-CT: Ein Jahr klinischer Einsatz.

The implementation of 64-slice scanners allows for isotropic imaging with shortened acquisition time. Beam-hardening and spiral artifacts can be reduced by using sophisticated tube technology with so called double-z-sampling. The following article is meant to provide a brief overview concerning substantial changes as they could be witnessed in clinical routine using a 64-slice scanner, with special focus on CT-angiography in general and CT-angiography of the coronaries.

Feasibility and usefulness of using swallow contrast-enhanced ultrasound to diagnose Zenker's diverticulum: preliminary results.

Zenker's diverticulum (ZD) may be misdiagnosed on conventional ultrasound as a thyroid nodule or other lesion. A barium esophagram is usually used to confirm the diagnosis; however, this procedure exposes the patient to radiation. The aim of this study was to evaluate the feasibility of using swallow contrast-enhanced ultrasound (swallow-CEUS) to diagnose ZD. Ten consecutive patients with ZD (7 men and 3 women, aged 67 ± 11 y) were included in the study. In 4 patients, ZD was incidentally found on head and neck ultrasound, and in 6 patients, ZD was suspected because of dysphagia. All lesions could be detected on conventional ultrasound before swallow-CEUS. Ten healthy volunteers (8 men and 2 women, aged 60 ± 12 y) were chosen as a control group. Written informed consent was obtained. With the patient in the sitting or upright position, conventional ultrasound was performed first to image the lesion, then the patient was asked to swallow ultrasound contrast agent (UCA) (2-4 drops of SonoVue diluted with about 200 mL of tap water). Transity of the contrast agent in the esophagus was imaged with CEUS. Retention of the UCA in the diverticulum was monitored for at least 3 min. All patients underwent a barium esophagram as the gold standard. Swallow-CEUS revealed that in all patients (100%), the UCA was transported from the pharynx to the esophagus while the patient swallowed. ZD appeared as a pouch-shaped structure at the posterior pharyngo-esophageal junction that retained UCA longer than 3 min. The barium esophagram confirmed the diagnosis of ZD in all patients. For the 10 volunteers, no abnormal structure (retaining UCA) was detected during or after swallowing of UCA. With the advantages of no radiation and bedside availability, swallow-CEUS may become a method of choice in confirmation of the diagnosis of ZD, especially when ZD is suspected on conventional ultrasound.

Phase I trial of strictly time-scheduled gemcitabine and cisplatin with concurrent radiotherapy in patients with locally advanced pancreatic cancer.

PURPOSE: Maximal therapeutic gain in xenograft sarcoma and toxicity for jejunal mucosa is time dependent for concurrent gemcitabine and radiotherapy (RT). We used a time-dependent schedule to determine the maximal-tolerated dose and dose-limiting toxicities (DLTs; Grade 4 hematologic or Grade 3 other toxicity). METHODS AND MATERIALS: Patients with pancreatic cancer (n = 33), periampullary carcinoma (n = 1), or bile duct cancer (n = 2) were treated with 3-day conformal RT with 50.4 Gy (tumor, lymphatics) plus a 5.4-Gy boost. Concurrent cisplatin (20 mg/m(2)/d on Days 1-5 and 29-33) and gemcitabine (initially 600 mg/m(2), weekly on Fridays 68 h before RT) were administered. Because of DLT, the doses were reduced to 500 mg/m(2) weekly and then 500, 400, or 300 mg/m(2) on Days 2, 5, 26, 33. RESULTS: DLT occurred at all dose levels of gemcitabine >300 mg/m(2). Fourteen patients were treated at the recommended Phase II dose of gemcitabine (300 mg/m(2)) without DLT. The response to chemoradiation allowed 10 of 30 initially unresectable patients with primary pancreatic carcinoma to undergo radical surgery, including a complete response in 2 cases. CONCLUSIONS: At the recommended Phase II dose, chemoradiation with gemcitabine and cisplatin can be administered safely in pancreatic carcinoma. However, at higher dose levels, toxicity is severe and frequent. Patients with a chance for conversion to resection could benefit from this schedule.

Quantitative parameters of image quality in multidetector spiral computed tomographic coronary imaging with submillimeter collimation.

Multidetector computed tomography (MDCT) permits visualization of the coronary arteries, but limited spatial and temporal resolution can lead to artifacts. We quantitatively evaluated the image quality that can be obtained with the latest generation of MDCT scanners with submillimeter collimation and increased gantry rotation speed. Thirty patients with angiographically proved absence of significant coronary artery stenoses (mean age 56 +/- 13 years, mean heart rate 62 +/- 13 beats/min) were studied by MDCT (12 x 0.75 mm collimation, 420-ms tube rotation, 210-ms temporal resolution, 500 mA, 120 kVp, retrospective electrocardiographic gating). In multiplanar reconstructions of the 4 major coronary arteries (left main, left anterior descending, left circumflex, and right coronary artery), the overall visualized vessel length and the length of segments without motion artifacts were measured. Vessel diameters at 8 predefined locations were measured in MDCT maximum intensity projections and in corresponding invasive angiograms. The mean lengths of visualized coronary arteries were left main 13 +/- 6 mm, left anterior descending 138 +/- 39 mm, left circumflex 84 +/- 34 mm, and right coronary artery 155 +/- 41 mm. On average, 93 +/- 13% of the total visualized vessel length was depicted without motion artifacts (left main 100 +/- 0%, left anterior descending 93 +/- 12%, left circumflex 91 +/- 17%, and right coronary artery 87 +/- 14%). The percentage of vessel length visualized free of motion artifacts was significantly higher in patients with a heart rate 60 beats/min (96 +/- 8% vs 89 +/- 17%, p <0.05). Vessel diameters in MDCT correlated closely to quantitative coronary angiography (R(2) 0.83 to 0.87). In conclusion, MDCT with submillimeter collimation and improved temporal resolution permits reliable visualization of the vessel lumen and accurate measurements of vessel dimensions.