CT fluoroscopy-guided percutaneous vertebroplasty in spinal malignancy: technical results, PMMA leakages, and complications in 202 patients.

OBJECTIVE: To retrospectively evaluate the incidence and clinical impact of local polymethylmethacrylate (PMMA) leaks and pulmonary cement embolisms occurring under CT fluoroscopy-guided vertebroplasty of symptomatic malignant vertebral osteolyses. MATERIALS AND METHODS: From December 2001 to June 2009, 202 cancer patients (116 women, 86 men; age 63.2±8.6 years) with painful malignant vertebral osteolyses underwent vertebroplasty, with or without vertebral compression fracture. A total of 331 vertebrae were treated in 231 sessions under CT fluoroscopy guidance (120 kV; 10­25 mA; single slice, 4-, 16-, and 128-row CT). In the pre-vertebroplasty CT, the following items were assessed: osteolytic destruction (0, ≤25, ≤50, ≤75, or ≤100%) of vertebral cross-sectional area, posterior wall, and circumference; presence of perivertebral and degree of epidural (no, mild, moderate) soft tissue involvement. Local PMMA leaks were analyzed using the post-vertebroplasty CT. Pulmonary cement embolisms were evaluated in all patients having undergone radiography (CR; n053) or CT (n088) of the chest after vertebroplasty due to their underlying disease. Patient charts were reviewed regarding adverse events. RESULTS: Of 331 treated vertebrae, 32, 20.2, and 15.7% showed more than 50% osteolytic involvement of the vertebral cross-sectional area, posterior wall, and circumference, respectively. Mild or moderate epidural involvement was seen in 13.0 and 8.4%. Local PMMA leakage rate was 58.6% (194 of 331 vertebrae). Pulmonary cement embolisms (segmental, n010; central, n01) were seen after 7.8% of the procedures with follow-up imaging of the chest. No major complications occurred within a 30-day period after vertebroplasty. CONCLUSION: Vertebroplasty of spinal malignancy can be safely performed under CT fluoroscopy guidance even in patients with substantial osteolytic involvement. In our patient collective, PMMA leaks and pulmonary cement embolisms visualized in post-procedural radiography and CT images had no clinical impact.

Transarterial hepatic yttrium-90 radioembolization in patients with unresectable intrahepatic cholangiocarcinoma: factors associated with prolonged survival.

INTRODUCTION: In unresectable intrahepatic cholangiocarcinoma (ICC), systemic chemotherapy often is viewed as the only option, although efficacy is limited. Radioembolization (RE) using yttrium-90 ((90)Y) microspheres is an accepted therapy for patients with hepatocellular-carcinoma or metastatic liver tumors. However, there are limited data on the value of RE in patients with ICC and few data on factors influencing prognosis. The purpose of our retrospective analysis was to establish which factors influenced time-to-progression (TTP) and overall survival (OS). METHODS: Patients with unresectable ICC were treated with (90)Y resin-microspheres and assessed at 3-monthly intervals. Radiologic response was evaluated by using Response Criteria in Solid Tumors (RECIST). Baseline characteristics, biochemical/clinical toxicities, and response were examined for impact on TTP and OS. RESULTS: Thirty-four treatments were administered to 33 patients without major complications. By RECIST, 12 patients had a partial response, 17 had stable disease, and 5 had progressive disease after 3 months. The median OS was 22 months posttreatment and 43.7 months postdiagnosis. Median TTP was 9.8 months. Survival and TTP were significantly prolonged in patients with ECOG 0 (vs. ECOG 1 or 2; median OS: 29.4, 10, and 5.1 months; TTP: 17.5, 6.9, and 2.4 months), tumor burden ≤25% (OS: 26.7 vs. 6 months; TTP: 17.5 vs. 2.3 months), or tumor response (PR or SD vs. PD; OS: 35.5, 17.7 vs. 5.7 months; TTP: 31.9, 9.8 vs. 2.5 months), respectively (P < 0.001). CONCLUSIONS: Radioembolization is an effective and safe option for patients with unresectable ICC. Predictors for prolonged survival are performance status, tumor burden, and RECIST response.

Renal cell carcinoma in patients with a solitary kidney after nephrectomy treated with radiofrequency ablation: mid term results.

This retrospective study aimed to evaluate the feasibility and effectiveness of radiofrequency ablation (RFA) in patients with solitary kidney for the treatment of renal cell carcinoma (RCC). Within 2 years 10 patients (seven males, three females; age 65+/-8 years) were treated. All patients had a history of nephrectomy of the contralateral kidney. The indications for RFA were inoperability or high probability of complete renal failure after surgical enucleation of the tumor. 13 tumors with a size between 1.9 and 4.2 cm (average 2.7 cm) were treated. In patients with a tumor diameter larger than 2.5 cm a transarterial embolization was performed prior to RFA to reduce heat sink effect and risk of bleeding. Therapeutical success was defined as a lack of contrast enhancement in follow up examinations and shrinking of the treated area. Furthermore all patients' renal function was monitored. RFA of renal tumors under CT-fluoroscopy was feasible in all patients. Within the follow up (3 and 24 months) no tumor recurrence or major complication was detected. One patient developed another RCC and was successfully treated with a second RF-ablation. None of the patients developed renal failure with the need of hemodialysis. In one of the patients a hemorrhage into the surrounding tissue was noticed, which stopped spontaneously. RFA is a valuable and effective therapeutical option in patients with solitary kidney suffering from inoperable renal cell carcinoma. The complication rate is small and an excellent tumor control can be achieved without deterioration of the renal function.

Radiofrequency ablation in the treatment of osteoid osteoma-5-year experience.

PURPOSE: This study aimed to determine the success and complication rates of radiofrequency ablation (RFA) in treatment of osteoid osteoma (OO) and duration of pain relief. Furthermore value of bone biopsy prior to the RFA was evaluated. MATERIALS AND METHODS: Within 61 months 39 patients (23 male, 16 female, 7-53 years, mean 18.7 years, median 17 years) suffering from osteoid osteoma were treated. Lesions were located in femur (n=20), tibia (n=10), spine (n=5), humerus (n=1), radius (n=1), talus (n=1) and pelvis (n=1). In children, RFA was performed under general anaesthesia, in adults conscious sedation was preferred. In 29 of 39 (74%) lesion biopsies were obtained. Cooling of skin was performed in OOs located in bones with minor soft tissue covering (tibia, radius) and saline flushing via an additional needle was performed if the OO was adjacent to nerval structures. Primary success rate, complications, symptom-free interval, follow-up and biopsy results were evaluated. RESULTS: Within observation period (1-61 months; median: 32 months) 38 of 39 patients were successfully treated and had no more complaints. In 3 of 38 patients relapse occurred after 1, 14 and 32 months and RFA was repeated. Two major complications (broken drill, infection) and 2 minor complications (hematoma, prolonged pain) were observed. Biopsy was able to prove diagnosis in 14 of 29 (48%) cases. CONCLUSIONS: Biopsy prior to treatment is not mandatory due to a remarkable amount of false negative findings in clinically and morphologically unambiguous cases of OO. RFA is a highly effective, efficient, minimally invasive and safe method for the treatment of OO.

CT-guided radiofrequency ablation in patients with hepatic metastases from breast cancer.

The purpose of this study was to evaluate technical success, technique effectiveness, and survival following radiofrequency ablation for breast cancer liver metastases and to determine prognostic factors. Forty-three patients with 111 breast cancer liver metastases underwent CT-guided percutaneous radiofrequency (RF) ablation. Technical success and technique effectiveness was evaluated by performing serial CT scans. We assessed the prognostic value of hormone receptor status, overexpression of human epidermal growth factor receptor 2 (HER2), and presence of extrahepatic tumor spread. Survival rates were calculated using the Kaplan-Meier method. Technical success was achieved in 107 metastases (96%). Primary technique effectiveness was 96%. During follow-up local tumor progression was observed in 15 metastases, representing a secondary technique effectiveness of 86.5%. The overall time to progression to the liver was 10.5 months. The estimated overall median survival was 58.6 months. There was no significant difference in terms of survival probability with respect to hormone receptor status, HER2 overexpression, and presence of isolated bone metastases. Survival was significantly lower among patients with extrahepatic disease, with the exception of skeletal metastases. We conclude that CT-guided RF ablation of liver metastases from breast cancer can be performed with a high degree of technical success and technique effectiveness, providing promising survival rates in patients with no visceral extrahepatic disease. Solitary bone metastases did not negatively affect survival probability after RF ablation.

CT fluoroscopy-guided percutaneous vertebroplasty for the treatment of osteolytic breast cancer metastases: results in 62 sessions with 86 vertebrae treated.

PURPOSE: This retrospective study aimed to assess the results of computed tomographic (CT) fluoroscopy-guided percutaneous vertebroplasty (PV) of painful osteolytic spinal metastases from breast cancer, focusing on the frequency and clinical impact of polymethylmethacrylate (PMMA) leaks. MATERIALS AND METHODS: Within 48 months, 53 patients (52 women; mean age of 62 y +/- 13) with painful osteolytic breast cancer metastases underwent vertebroplasty. Eighty-six vertebrae were treated in 62 sessions under CT fluoroscopy guidance (single slice and four- and 16-row CT). In the planning CT scan, osteolytic destruction (ie, none, < or =25%, < or =50%, < or =75%, or < or =100%) was assessed regarding the vertebral cross-sectional area, the cortical border of the spinal canal, and the outer circumference. CT performed after vertebroplasty was used to detect local PMMA leaks (intradiscal, intraspinal, paravertebral, intercostovertebral/posterolateral, and vascular). Patient charts were reviewed with respect to adverse events. Clinical outcome was assessed on a visual analog scale (VAS) 24 hours before, immediately after, and 6 months after PV. RESULTS: Overall, 37.2%, 12.8%, and 1.2% of vertebrae (N = 86) showed at least a 50% osteolytic involvement of the cross-sectional area, spinal canal, and outer vertebral cortex, respectively. Intradiscal, intraspinal, paravertebral, and intercostovertebral/posterolateral leaks were seen in 31.3%, 26.9%, 26.9%, and 14.9% of vertebrae, respectively. The ratio of basivertebral to segmental venous leaks was 22.4%/23.9%. No major complications (eg, radiculopathy or pulmonary embolism) occurred. VAS scores decreased significantly (P < .05) from 6.4 at 24 hours before PV to 3.4 at a mean follow-up of 9.2 months. CONCLUSIONS: PV of osteolytic breast cancer metastases can be performed safely under CT fluoroscopic guidance even with substantial involvement of the vertebral cross-sectional area or cortical bone. A high clinical success rate was achieved and cortical and vascular PMMA leaks had no impact.

Hepatic yttrium-90 radioembolization of chemotherapy-refractory colorectal cancer liver metastases.

PURPOSE: To present data for radioembolization with yttrium-90 ((90)Y) resin microspheres in patients with colorectal cancer liver metastases in whom currently available therapies had failed. MATERIALS AND METHODS: Retrospective review was conducted of case files of patients with colorectal cancer liver metastases in whom chemotherapy had failed, prompting hepatic (90)Y radioembolization administered as a single-session, whole-liver treatment. Imaging and laboratory follow-up results were available for 36 patients. Response and toxicity were assessed by computed tomography/magnetic resonance imaging with the Response Evaluation Criteria in Solid Tumors and the National Cancer Institute's Common Terminology Criteria for Adverse Events, version 3.0. RESULTS: Forty-one patients (mean age, 61 years; 30 men) received hepatic (90)Y radioembolization with resin microspheres (mean activity, 1.9 GBq). At a median interval of 2.9 months after radioembolization, partial response, stable disease, and progressive disease were demonstrated in seven, 25, and four patients, respectively. Median overall survival was 10.5 months, with improved survival for patients with a decrease in carcinoembryonic antigen level (19.1 months vs 5.4 months) and imaging response (29.3 months vs 4.3 months; P = .0001). Except for one instance of treatment-associated cholecystitis (grade 4 toxicity) and two gastric ulcers (grade 2 toxicity), no severe toxicities were observed. CONCLUSIONS: Hepatic (90)Y radioembolization can be performed with manageable toxicity in patients with colorectal cancer liver metastases whose disease is refractory to chemotherapy. The antitumoral effect is supported by imaging and tumor marker responses. Further investigation is warranted to determine the optimal use of this emerging therapeutic modality.

Radioembolization in patients with hepatic metastases from breast cancer.

PURPOSE: To determine the safety of and survival outcomes associated with single-session, whole-liver radioembolization with Yttrium-90 (90Y)-labelled resin microspheres in patients with nonresectable liver metastases from breast cancer that were refractory to other treatments. MATERIALS AND METHODS: Thirty patients underwent radioembolization with 90Y-labeled resin microspheres infusion in a single-session, whole-liver treatment. All patients had undergone polychemotherapy regimens including at least anthracyclines and taxanes, hormonal therapy, and trastuzumab where applicable. Follow-up data were available for 23 patients. After treatment, the authors assessed tumor response with computed tomography and/or magnetic resonance imaging by using Response Evaluation Criteria in Solid Tumors (RECIST), laboratory and clinical toxicities, and survival. RESULTS: A mean activity of 1.9 GBq of 90Y was delivered. Follow-up at a median of 4.2 months demonstrated partial response, stable disease, and progressive disease in 61%, 35%, and 4% of patients, respectively. With respect to tumor diameters, imaging revealed a maximum and minimum response of -64.8% to +23.6%, respectively (mean, 29.2%; median, 39.7%). The median follow-up time was 14.2 months. The median overall survival was 11.7 months. The median survival of responders and nonresponders was 23.6 and 5.7 months, respectively, and the median survival of patients with and patients without extrahepatic disease was 9.6 and 16 months. Clinically significant toxicities with the appearance of increasing transaminase level, increasing bilirubin level, nausea and vomiting, gastric ulcers, and ascites occurred in eight of 30 patients. One patient's death was attributed to treatment-related hepatic toxicity. CONCLUSIONS: Single-session, whole-liver 90Y radioembolization can be performed with an acceptable toxicity profile in patients with liver metastases from breast cancer. Response to radioembolization in these patients is supported by the decrease in tumor size. Further investigation is warranted to prove survival benefit.

Radiofrequency ablation in combination with osteoplasty in the treatment of painful metastatic bone disease.

PURPOSE: To evaluate the feasibility and effectiveness of combining radiofrequency (RF) ablation and osteoplasty for pain reduction in the treatment of painful osteolytic metastases. MATERIALS AND METHODS: Within 5 years, 22 patients (15 men and seven women; median age, 64 years) with 28 lesions located in the thoracic and lumbar spine, sacrum, pelvis, acetabulum, femur, and tibia were treated. Underlying tumors were breast, lung, renal cell, thyroid, cancer of unknown primary, and multiple myeloma. RF ablation was performed with the patient under moderate sedation and computed tomographic fluoroscopy guidance and was immediately followed by cement injection. Pain relief was evaluated with the visual analogue scale (VAS) score and the extent to which analgesics could be reduced. Clinical success was defined as a substantial reduction in pain and/or a reduced demand for analgesics, and technical success was defined as distribution of cement between both endplates of a vertebral body or at least 75% filling of osteolyses in other bones. RESULTS: Technical success and pain relief was achieved in all patients. Pain ratings with the VAS decreased from a mean of 8.5 to a mean of 5.5 after 24 hours (P < .01), and a further decrease was detected after 3 months to 3.5 (P < .01). The amount or strength of analgesics was reduced in 15 patients and remained unchanged in five. In two patients, the amount of analgesics increased due to tumor progression elsewhere. No major complication, no clinically obvious fracture of a formerly treated bone or treatment-related death, occurred. CONCLUSIONS: RF ablation and osteoplasty can be combined within one session and is both feasible and useful for the treatment of osteolytic bone metastases with regard to pain relief.

RFA of renal cell carcinoma in a solitary kidney.

The incidence of renal cell carcinoma (RCC) is increasing worldwide and diagnosis is made in an earlier stage due to increasing use of CT and ultrasound. Patients with a history of RCC have a high risk to develop another RCC within their remaining kidney. Especially, patients after tumor nephrectomy have to undergo follow-up examinations regularly allowing an early detection of new RCCs. Especially in patients with solitary kidney gold standard therapy (nephron-sparing surgery) can often account for consecutive renal failure with the need for hemodialysis. Percutaneous radiofrequency ablation (RFA) gained worldwide acceptance for the treatment of liver tumors in patients unable to undergo surgery. Furthermore, during the past few years, there is an increasing amount of publications dealing with the effectiveness of minimally invasive therapies like RFA in patients with renal masses. However, in the subgroup of patients with solitary kidney suffering from RCC, there are only case reports regarding safety and midterm outcome available so far. Therefore, the aim of this article is to briefly describe the basic technical principles of RFA and then focus on indications, technique, safety and the midterm outcome after treatment in terms of renal function and relapse.

Radiofrequency ablation of colorectal liver metastases: mid-term results in 68 patients.

UNLABELLED: The aim of this retrospective study was to evaluate the efficacy and medium-term survival, after percutaneous radiofrequency ablation (RFA), in patients suffering from hepatic metastases of colorectal cancer. PATIENTS AND METHODS: Between 2000 and 2004, 68 patients (42 men, 26 women; mean age 63 years, range: 38-87 years), with non-resectable liver metastases from colorectal cancer, were treated by RFA subsequently or parallel to chemotherapy. The procedures were mainly performed under conscious sedation and local anesthesia using computed tomography fluoroscopy guidance. The number of lesions, the primary success rate, complications, follow-up time and disease-free survival, as well as the local recurrence rate, were evaluated. RESULTS: One-hundred and eighty-three metastases with a mean diameter of 22.8 mm (5-50 mm) in 68 patients (2.7 +/- 1.1 lesions / patient) were successfully treated using RFA. No major complications and only 4 minor complications were noted. Over an average follow-up period of 21.4 +/- 10.6 months (range, 8 to 38 months), Kaplan-Meier analysis demonstrated a probability of 82% of remaining locally disease-free and a probability of 68% of surviving the first 38 months after treatment. CONCLUSION: For patients with non-resectable hepatic metastases of colorectal cancer, RFA is a safe option in a multimodal treatment concept and may lead to an improvement in survival.

Characterization of hepatocellular tumors: value of mangafodipir-enhanced magnetic resonance imaging.

PURPOSE: To assess the value of mangafodipir trisodium-enhanced MR imaging for characterization of hepatocellular lesions. MATERIALS AND METHODS: Magnetic resonance images of 41 patients with 48 histopathologically proven hepatocellular lesions (20 cases of focal nodular hyperplasia [FNH], 4 adenomas, 15 hepatocellular carcinomas [HCCs], 7 regenerative nodules, and 2 others) were retrospectively studied. Magnetic resonance imaging was performed on a 1.5-T unit (Vision, Siemens, Erlangen, Germany; ACS-NT, Philips, Best, The Netherlands) using T2-weighted, fat-saturation, turbo spin echo imaging and T1-weighted gradient echo imaging before and 20 minutes after infusion of 5 micromol/kg mangafodipir (Amersham Health, Oslo, Norway). Qualitative analysis by 4 blinded independent readers included assessment of unenhanced images and, in a second step, assessment of unenhanced and contrast-enhanced images together. Lesions were classified as benign or malignant using a 5-point scale, and readers made a specific diagnosis. RESULTS: For characterization of hepatocellular lesions, mangafodipir-enhanced imaging was significantly superior to unenhanced imaging (P < 0.05). On receiver operating characteristic analysis, the area under the curve was 0.768 (95% confidence interval: 0.633-0.903) for unenhanced images and 0.866 (95% confidence interval: 0.767-0.966) for evaluation of unenhanced and contrast-enhanced images together (P < 0.05). Analysis of enhancement patterns aided in characterization and classification of tumors. CONCLUSION: Administration of mangafodipir improves the differentiation between adenoma or HCC and "nonsurgical" lesions (FNH or regenerative nodules). The accuracy for arriving at a specific diagnosis is higher when unenhanced and mangafodipir-enhanced images are considered together than for unenhanced MR images alone.

Enhancement of focal liver lesions at gadoxetic acid-enhanced MR imaging: correlation with histopathologic findings and spiral CT--initial observations.

PURPOSE: To detect hepatocyte-selective enhancement of focal lesions with gadoxetic acid at magnetic resonance (MR) imaging and to correlate enhancement in hepatocyte-selective phases with histopathologic findings and in arterial and portal venous phases with biphasic computed tomographic (CT) findings. MATERIALS AND METHODS: Study was supported by local ethics committee; all patients gave written informed consent. In 19 men and 14 women recruited in three clinical studies, histopathologic correlation and CT scans of 41 focal lesions (13 primary malignant lesions, 21 metastases, three adenomas, three cases of focal nodular hyperplasia [FNH], and one cystadenoma) and ultrasonographic confirmation of five cysts were available. MR was performed before and during arterial and portal venous phases and in hepatocyte-selective phases 10 and 20 minutes after injection of gadoxetic acid. Enhancement was evaluated in consensus by two observers. Enhancement pattern and morphologic features during arterial and portal venous phases were correlated between gadoxetic acid-enhanced MR and CT images by means of adjusted chi(2) test. RESULTS: Hepatocyte-selective uptake was observed 10 and 20 minutes after injection in FNH (three of three), adenoma (two of three), cystadenoma (one of one), and highly differentiated hepatocellular carcinoma (HCC [grade G1], two of four). Uptake was not detected in metastases (21 of 21), cholangiocarcinoma (three of three), combined hepatocellular cholangiocarcinoma (one of one), undifferentiated carcinoma (one of one), moderately or poorly differentiated HCC (grade G2-G3) (four of four), HCC (grade G1, two of four), adenoma with atypia (one of three), or cysts (five of five). During arterial and portal venous phases, there was high overall agreement rate of 0.963 between gadoxetic acid-enhanced MR and CT (simultaneous 95% confidence interval: 0.945, 0.981). CONCLUSION: Liver-specific enhancement of focal lesions is hepatocyte selective and correlates with various histopathologic diagnoses regarding presence of certain hepatocytic functions. Arterial and portal venous MR images obtained with gadoxetic acid are comparable to those of CT.

Massive air embolism during interventional laser therapy of the liver: successful resuscitation without chest compression.

We report on a rare, acute, life-threatening complication during percutaneous thermal therapy for hepatic metastases. Massive cardiac air embolism occurred during a maneuver of deep inspiration after the dislodgment of an introducer sheath into a hepatic vein. The subsequent cardiac arrest was treated successfully by immediate transthoracic evacuation of the air by needle aspiration followed by electrical defibrillation. In procedures that may be complicated by gas embolism, cardiopulmonary resuscitation should not be initiated before considering the likelihood of air embolism, and eventually aspiration of the gas.

MRI characteristics in focal hepatic disease before and after administration of MnDPDP: discriminant analysis as a diagnostic tool.

The aim of this study was to determine if different types of focal hepatic lesions can be differentiated by specific quantitative and qualitative imaging characteristics pre- and post-Mangafodipir trisodium (MnDPDP) administration using a computerized multivariable, discriminant analysis (DA). In a multicenter trial, 151 patients with focal liver disease were studied at 1.5 and 1.0 T using gradient-recalled echo T1 and fast spin-echo T2-weighted images pre and post MnDPDP (0.005 mmol/kg b.w.) i.v. administration. Analysis could be performed in 141 of 151 of the patients. The variables used in both single variable analysis and DA included contrast-to-noise ratios pre and post MnDPDP, presence of rim enhancement, margin, and heterogeneity of a lesion pre and post MnDPDP. The classification of diagnoses using DA was compared with a standard of reference (HCC in 23%, metastases in 25%, cyst in 13%, FNH in 10%, hemangioma in 11%, and other or no lesion in 18% of the patients; histology in 49%, long-term follow-up in 51% of the cases). In the differentiation of the various hepatic lesions, CNR together with the presence of heterogeneity or rim enhancement as variables for DA gave the highest sensitivity, specificity, and accuracy which ranged between 65 and 93, 44 and 83, and 65 and 86%, respectively. The DA models based on post-MnDPDP variables showed better classification results than the models based on pre-MnDPDP variables. An improvement of accuracy was observed when differentiating HCC from FNH lesion groups (48.9-67.4%; p < or = 0.05), and when differentiating HCC from metastasis lesion groups (68.3-84.1%; p < or = 0.01). In all regards there was no difference for T2-weighted images pre and post MnDPDP. By combining quantitative and qualitative variables, DA proved to be a useful tool in lesion discrimination. Due to considerable heterogeneity within some of the lesion type groups, the definite diagnostic impact of MnDPDP cannot be completely established yet, and further investigation is still necessary.

Subsegmental pulmonary emboli: improved detection with thin-collimation multi-detector row spiral CT.

PURPOSE: To compare different reconstruction thicknesses of thin-collimation multi-detector row spiral computed tomographic (CT) data sets of the chest for the detection of subsegmental pulmonary emboli. MATERIALS AND METHODS: A multi-detector row spiral CT protocol for the diagnosis of pulmonary embolism was used that consisted of scanning the entire chest with 1-mm collimation within one breath hold. In 17 patients with central pulmonary embolism, the raw data were used to perform reconstructions with 1-mm, 2-mm, and 3-mm section thicknesses. For each set of images, each subsegmental artery was independently graded by three radiologists as open, containing emboli, or indeterminate. RESULTS: For the rate of detection of emboli in subsegmental pulmonary arteries, use of the 1-mm section width yielded an average increase of 40% when compared with the use of 3-mm-thick sections (P <.001) and of 14% when compared with the use of 2-mm-thick sections (P =.001). With the use of 1-mm sections versus 3-mm sections, the number of indeterminate cases decreased by 70% (P =.001). Interrater agreement was substantially better with the use of 1-mm and 2-mm sections than with the use of 3-mm sections. CONCLUSION: For the diagnosis of subsegmental pulmonary emboli at multi-detector row CT, the use of 1-mm section widths results in substantially higher detection rates and greater agreement between different readers than the use of thicker sections.