Abdominal musculature segmentation and surface prediction from CT using deep learning for sarcopenia assessment.

PURPOSE: The purpose of this study was to build and train a deep convolutional neural networks (CNN) algorithm to segment muscular body mass (MBM) to predict muscular surface from a two-dimensional axial computed tomography (CT) slice through L3 vertebra. MATERIALS AND METHODS: An ensemble of 15 deep learning models with a two-dimensional U-net architecture with a 4-level depth and 18 initial filters were trained to segment MBM. The muscular surface values were computed from the predicted masks and corrected with the algorithm's estimated bias. Resulting mask prediction and surface prediction were assessed using Dice similarity coefficient (DSC) and root mean squared error (RMSE) scores respectively using ground truth masks as standards of reference. RESULTS: A total of 1025 individual CT slices were used for training and validation and 500 additional axial CT slices were used for testing. The obtained mean DSC and RMSE on the test set were 0.97 and 3.7 cm2 respectively. CONCLUSION: Deep learning methods using convolutional neural networks algorithm enable a robust and automated extraction of CT derived MBM for sarcopenia assessment, which could be implemented in a clinical workflow.

Three artificial intelligence data challenges based on CT and MRI.

PURPOSE: The second edition of the artificial intelligence (AI) data challenge was organized by the French Society of Radiology with the aim to: (i), work on relevant public health issues; (ii), build large, multicentre, high quality databases; and (iii), include three-dimensional (3D) information and prognostic questions. MATERIALS AND METHODS: Relevant clinical questions were proposed by French subspecialty colleges of radiology. Their feasibility was assessed by experts in the field of AI. A dedicated platform was set up for inclusion centers to safely upload their anonymized examinations in compliance with general data protection regulation. The quality of the database was checked by experts weekly with annotations performed by radiologists. Multidisciplinary teams competed between September 11th and October 13th 2019. RESULTS: Three questions were selected using different imaging and evaluation modalities, including: pulmonary nodule detection and classification from 3D computed tomography (CT), prediction of expanded disability status scale in multiple sclerosis using 3D magnetic resonance imaging (MRI) and segmentation of muscular surface for sarcopenia estimation from two-dimensional CT. A total of 4347 examinations were gathered of which only 6% were excluded. Three independent databases from 24 individual centers were created. A total of 143 participants were split into 20 multidisciplinary teams. CONCLUSION: Three data challenges with over 1200 general data protection regulation compliant CT or MRI examinations each were organized. Future challenges should be made with more complex situations combining histopathological or genetic information to resemble real life situations faced by radiologists in routine practice.

Do regions of interest location and type influence liver stiffness measurement using magnetic resonance elastography?

PURPOSE: To assess the variability of liver stiffness measurements using magnetic resonance elastography (MRE) at 1.5T, depending on different approaches of regions of interest (ROIs) drawing. MATERIAL AND METHODS: Fifty consecutive patients with successful liver MRE were included. There were 32 men and 18 women with a mean age of 52±14 (SD) years (range: 20-85 years). MRE was acquired using a gradient recalled-echo MRE sequence. At the level of the portal bifurcation, one observer drawn in the right liver first 3 elliptical ROI and then one free-hand ROI, as large as possible based on the confidence map and the anatomy. Three additional elliptical ROIs were further drawn on the slice above and 3 other on the slice below, for a total of 9 elliptical ROIs. The average value of liver stiffness in the 3 elliptical ROIs of the central slice and the one from the 9 elliptical ROIs were computed. Three liver stiffness values were obtained for each patient from the 3 measurement methods (one free-hand ROI, 3 elliptical ROIs and 9 elliptical ROIs). Inter-method variability was assessed using the intra-class correlation coefficient (ICC) and Bland-Altman analysis. RESULTS: The variability between the 3 methods was excellent with ICC>0.978 (P<0.0001). The Bland-Altman analysis revealed high agreement between the 3 methods with bias<0.45kPa and limits of agreement<±1.13kPa. The variability was lower when comparing a large free-hand ROI and the 3-elliptical ROIs, than when comparing the 9-elliptical ROIs to one of the other methods. CONCLUSION: Our results show that the variability between the 3 methods of ROI drawing and placement is very low.

FOLFIRINOX as induction treatment in rectal cancer patients with synchronous metastases: Results of the FFCD 1102 phase II trial.

AIM OF THE STUDY: The optimal therapeutic strategy in patients with rectal cancer and synchronous unresectable metastases remains unknown. We evaluated the efficacy of FOLFIRINOX induction therapy in this setting. PATIENTS AND METHODS: Chemotherapy-naïve patients received at least 8 cycles of FOLFIRINOX. The primary end-point was the 4-month disease control (4 m DC) rate. Tumour responses were centrally reviewed and assessed by computed tomography scan for metastases (Response Evaluation Criteria in Solid Tumours criteria) and magnetic resonance imaging for rectal tumorus. With a Simon 2-stage design and a targeted (H1) 4 m DC > 75%, 65 patients were enrolled from July 2012 to February 2015: male, 78%; median age, 61 years; performance status, 0-1, 98%; liver metastases, 92%; ≥2 metastatic sites, 63%. RESULTS: Fifty-six (85%) of the 65 patients received the 8 planned FOLFIRINOX cycles. The primary objective was achieved (4 m DC rate: 94%; 95% confidence interval [CI], 86.3-97.8). Primary tumour symptoms decreased from 72% at baseline to 10% at 4 months. Response rate was 86%, and a >70% primary tumour volume decrease was seen in 63% of patients. Forty-four patients (68%) had at least one grade 3 side-effect; no toxic deaths occurred. Median follow-up was 35.0 months (95% CI, 31.3-43.7). Median progression-free survival and overall survival were 10.9 m (95% CI, 8.8-12.9) and 33.4 m (95% CI, 22.6-38.2), respectively. CONCLUSION: Upfront FOLFIRINOX is feasible and allows good local and distant control. It therefore offers the opportunity to choose the best therapeutic strategy for each patient and to personalise treatment according to the local and distant efficacy results of this induction step. TRIAL REGISTRATION: Clinicaltrials.gov, NCT01674309.

Transition zone and anterior stromal prostate cancers: Evaluation of discriminant location criteria using multiparametric fusion-guided biopsy.

PURPOSE: The purpose of this study was to evaluate precise location criteria on magnetic resonance imaging (MRI) to improve detection of transition zone (TZ) and anterior stroma (AS) prostate cancers using targeted MRI/transrectal ultrasound fusion biopsies as a reference standard. MATERIAL AND METHODS: Ninety-six men (mean age: 65 years±7.7 [SD] [range: 46-83 years]) with an elevated prostate-specific antigen (PSA) (PSA≥4ng/mL) who underwent standard and targeted biopsies on a TZ/AS suspicious lesion were included. The database was reviewed to assess topographical and morphological features of each suspicious lesion on MR images (T2-weighted anatomical images on 1.5T MRI or 3T) including PI-RADS score assessed by a senior radiologist. Histopathological examination of MRI-transrectal ultrasound fusion biopsy specimens was used as the reference standard. RESULTS: Ninety patients had a positive targeted biopsy with a median [IQR] lesion size of 16mm [13-20mm]. Homogeneous hypointensity on T2-weighted mages, lenticular shape, lack of capsule and indistinct margins were present in 77/90 (85%) patients. All TZ/AS prostate cancers were located in the anterior half of the prostate: 3% at the base, 69% in the mid gland and 28% at the apex. Lesions were mainly located close to or within the AS (74%) and more rarely laterally compressed close to the peripheral anterior horn. CONCLUSION: Our results suggest that specific topographic criteria of TZ and AS prostate cancers could add independent information to the usual diagnostic criteria in prostate MRI. Transrectal ultrasound fusion-targeted biopsies based on these specific criteria improve volume estimation of prostate cancers with substantial impact for prognosis and treatment planning.

Comparison of semi-automated and manual methods to measure the volume of prostate cancer on magnetic resonance imaging.

PURPOSE: The purpose of this study was to determine the accuracy of manual semi-automated and volumetric measurements to assess prostate cancer volume on multiparametric magnetic resonance imaging (MP-MRI) using whole-mount histopathology for validation. MATERIALS AND METHODS: We evaluated 30 consecutive men (median age, 65.7 years; interquartile range [IQR], 61.5-70.9 years) with a median prostatic specific antigen of 8.5ng/dL (IQR, 5.5-10.5ng/dL), who underwent MP-MRI before radical prostatectomy. Index tumor volume was determined prospectively and independently on the basis of MRI and whole-mount section volumetric assessment using the maximum histologic diameter (MHD) and the histologic volume (HV). The MRI index tumor volume was determined by two independent radiologists using a single measurement of the maximum tumor dimension (MTD), a simplified MR ellipsoid volume (MREV) calculation and a MR region of interest volume (MROV) segmentation displayed by a commercially available OsiriX®. MTD was compared to MHD, whereas MREV and MROV were compared to HV. RESULTS: Thirty index lesions (median HV, 1.514 cm3; IQR, 0.05-3.780 cm3) were analyzed. The MREV, MROV and HD were significantly correlated with each other (r>0.5). Inter-observer agreement for measurements was good for each method (r>0.780). The MTD was the best predictor of maximum histologic diameter (r=0.980 and 0.791) and had an excellent inter-variability correlation (P<0.0001). CONCLUSION: Prostate cancer histologic volume can be assessed using MREV or MROV with a good accuracy and low inter-observer variability. MTD has the lowest inter-observer variability and provides best degrees of correlation with MHD. MTD should be used on MRI for selecting and following patients for active surveillance and staging before focal treatment of prostate cancer.

Selection of an early biomarker for vascular normalization using dynamic contrast-enhanced ultrasonography to predict outcomes of metastatic patients treated with bevacizumab.

BACKGROUND: Dynamic contrast-enhanced ultrasonography (DCE-US) has been used for evaluation of tumor response to antiangiogenic treatments. The objective of this study was to assess the link between DCE-US data obtained during the first week of treatment and subsequent tumor progression. PATIENTS AND METHODS: Patients treated with antiangiogenic therapies were included in a multicentric prospective study from 2007 to 2010. DCE-US examinations were available at baseline and at day 7. For each examination, a 3 min perfusion curve was recorded just after injection of a contrast agent. Each perfusion curve was modeled with seven parameters. We analyzed the correlation between criteria measured up to day 7 on freedom from progression (FFP). The impact was assessed globally, according to tumor localization and to type of treatment. RESULTS: The median follow-up was 20 months. The mean transit time (MTT) evaluated at day 7 was the only criterion significantly associated with FFP (P = 0.002). The cut-off point maximizing the difference between FFP curves was 12 s. Patients with at least a 12 s MTT had a better FFP. The results according to tumor type were significantly heterogeneous: the impact of MTT on FFP was more marked for breast cancer (P = 0.004) and for colon cancer (P = 0.025) than for other tumor types. Similarly, the differences in FFP according to MTT at day 7 were marked (P = 0.004) in patients receiving bevacizumab. CONCLUSION: The MTT evaluated with DCE-US at day 7 is significantly correlated to FFP of patients treated with bevacizumab. This criterion might be linked to vascular normalization. AFSSAPS NO: 2007-A00399-44.

mTOR-inhibitor treatment of metastatic renal cell carcinoma: contribution of Choi and modified Choi criteria assessed in 2D or 3D to evaluate tumor response.

PURPOSE: To determine whether 2D or 3D Choi and modified Choi (mChoi) criteria could assess the efficacy of everolimus against metastatic renal cell carcinoma (mRCC). METHODS: RECIST-1.1, Choi, and mChoi criteria were applied retrospectively to analyse baseline and 2-month contrast-enhanced computed tomography (CECT) images in 48 patients with mRCC enrolled in the everolimus arm of the French randomized double-blind multicentre phase III trial comparing everolimus versus placebo (RECORD-1). The primary endpoint was centrally reviewed progression-free survival (PFS) calculated from the initial RECORD-1 analysis. Mean attenuation was determined for 2D target lesion regions of interest drawn on CECT sections whose largest diameters had been measured, and for the 3D whole target lesion. RESULTS: The median PFS was 5.5 months. The median PFS for everolimus responders defined using 3D mChoi criteria was significantly longer than for non-responders (7.6 versus 5.4 months, respectively), corresponding to a hazard ratio for progression of 0.45 (95 % CI: 0.22-0.92), with respective 1-year survival rates of 31 % and 9 %. No other 2D or 3D imaging criteria at 2 months identified patients who would benefit from everolimus. CONCLUSIONS: At 2 months, only 3D mChoi criteria were able to identify mRCC patients with a PFS benefit from everolimus. KEY POINTS: Choi criteria could not identify everolimus-treated patients with significantly prolonged PFS. mCHOI enabled identification of everolimus-treated mRCC patients with a PFS benefit. 3D attenuation measurement criteria appeared to perform better than single-slice measurement.

Extra-intestinal malignancies in inflammatory bowel diseases: An update with emphasis on MDCT and MR imaging features.

Inflammatory bowel diseases (IBD) are associated with an increased risk of gastrointestinal cancers and more specifically in sites affected by chronic inflammation. However, patients with IBD have also an increased risk for developing a variety of extra-intestinal cancers. In this regard, hepatobiliary cancers, such as cholangiocarcinoma, are more frequently observed in IBD patients because of a high prevalence of primary sclerosing cholangitis, which is considered as a favoring condition. Extra-intestinal lymphomas, mostly non-Hodgkin lymphomas, and skin cancers are also observed with an increased incidence in IBD patients by comparison with that in patients without IBD. This review provides an update on demographics, risk factors and clinical features of extra-intestinal malignancies, including cholangiocarcinoma, hepatocellular carcinoma and lymphoma, that occur in patients with IBD along with a special emphasis on the multidetector row computed tomography and magnetic resonance imaging features of these uncommon conditions.

An automatic respiratory gating method for the improvement of microcirculation evaluation: application to contrast-enhanced ultrasound studies of focal liver lesions.

Contrast-enhanced ultrasound (CEUS), with the recent development of both contrast-specific imaging modalities and microbubble-based contrast agents, allows noninvasive quantification of microcirculation in vivo. Nevertheless, functional parameters obtained by modeling contrast uptake kinetics could be impaired by respiratory motion. Accordingly, we developed an automatic respiratory gating method and tested it on 35 CEUS hepatic datasets with focal lesions. Each dataset included fundamental mode and cadence contrast pulse sequencing (CPS) mode sequences acquired simultaneously. The developed method consisted in (1) the estimation of the respiratory kinetics as a linear combination of the first components provided by a principal components analysis constrained by a prior knowledge on the respiratory rate in the frequency domain, (2) the automated generation of two respiratory-gated subsequences from the CPS mode sequence by detecting end-of-inspiration and end-of-expiration phases from the respiratory kinetics. The fundamental mode enabled a more reliable estimation of the respiratory kinetics than the CPS mode. The k-means algorithm was applied on both the original CPS mode sequences and the respiratory-gated subsequences resulting in clustering maps and associated mean kinetics. Our respiratory gating process allowed better superimposition of manually drawn lesion contours on k-means clustering maps as well as substantial improvement of the quality of contrast uptake kinetics. While the quality of maps and kinetics was satisfactory in only 11/35 datasets before gating, it was satisfactory in 34/35 datasets after gating. Moreover, noise amplitude estimated within the delineated lesions was reduced from 62 ± 21 to 40 ± 10 (p < 0.01) after gating. These findings were supported by the low residual horizontal (0.44 ± 0.29 mm) and vertical (0.15 ± 0.16 mm) shifts found during manual motion correction of each respiratory-gated subsequence. The developed technique could be used as a basis for accurate quantification of perfusion parameters for the evaluation and follow-up of patients under antiangiogenic therapies.

[Evaluation of a computer aided detection system for lung nodules with ground glass opacity component on multidetector-row CT]. / Evaluation d'un système de détection assisté par ordinateur des nodules parenchymateux pulmonaires avec verre dépoli au scanner multidétecteur.

PURPOSE: To determine the performance of a CAD system for lung nodules with ground glass opacity component on multidetector-row CT. Materials and methods. The CT examinations of 17 patients with at least one persistent subsolid nodule were reviewed. A first non-blinded consensus review by two expert radiologists resulted in the detection of 104 subsolid nodules larger than 3 mm (74 nodules of ground glass attenuation and 30 mixed nodules with solid and ground glass components). The results from this review were used as a gold standard to determine the performances of the CAD system and 3 independent clinical radiologists involved with the primary interpretations. RESULTS: The sensitivity of the CAD system for the detection of ground glass opacities and mixed nodules was 53% and 73% respectively. These values were not statistically different from the values for the 3 independent observers (42-66% for ground glass opacities and 63-80% for mixed nodules). The sensitivity of each observer significantly increased when the nodules detected by the CAD system were added to those detected by each observer (p<0.0001). CONCLUSION: A CAD system has a potential impact on the detection rate of subsolid nodules by radiologists.

[Imaging of the postsurgical liver]. / Imagerie du foie opéré

The appearance of the normal postsurgical liver and of potential complications specific to the type of liver resection performed (partial hepatectomy, cyst fenestration, RF ablation) must be well known by radiologists for early detection and treatment of postoperative complications. Early postoperative imaging of the liver aims at detecting vascular, biliary and extrahepatic complications and relies mainly on Doppler US and CT.

[Real-time contrast-enhanced ultrasound in the evaluation of focal liver lesions: diagnostic efficacy and economical issues from a French multicentric study]. / Echographie de contraste temps réel dans la prise en charge diagnostique des lésions nodulaires hépatiques: évaluation des performances diagnostiques et de l'impact économique sur une étude multicentrique française.

The recent introduction of high-end ultrasound equipment combined with recent contrast agents provides marked improvements in the characterization of focal liver lesions as previously reported by monocentric studies. The aim of the present study was to evaluate the diagnostic performance of Contrast-Enhanced Ultrasonography (CEUS) using SonoVue as well as its medico-economic value for characterization of focal liver lesions. These nodules were not characterized on previous CT or conventional sonography. This prospective multicentric study conducted in 15 French centres found diagnostic performances similar to those reported for CT and MRI, with a concordance rate of 84.5%, sensitivity greater than 80% and specificity greater than 90% for all types of lesions. Higher acceptance was found for CEUS compared to other imaging modalities. Economical assessment based on examination reimbursment and contrast agent cost showed a lower cost for contrast ultrasound versus CT and MRI. This French multicentric study confirmed the high diagnostic value of CEUS for focal liver lesion characterization and demonstrated a lower economical impact compared to other imaging modalities such as CT and MRI.

[Tissue attenuation in small animals on contrast enhanced ultrasound]. / Prise en compte de l'atténuation ultrasonore en présence d'agents de contraste chez le petit animal.

Despite recent advances in contrast-enhanced ultrasound imaging, evaluation of tissue perfusion with contrast-enhanced ultrasound is still impaired by shadowing effects. These effects are particularly relevant in small animal studies due to high frequency imaging. Current methods of tissue attenuation correction are not suited for contrast-enhanced ultrasound examinations, because microbubble acoustic response to ultrasound waves is far more complex than that of tissues. A method allowing in vivo tissue attenuation correction in the presence of contrast agents is presented.

[Computer-aided detection of lung nodules on thin collimation MDCT: impact on radiologists' performance]. / Evaluation de l'impact d'un système CAD sur la performance des radiologues pour la détection des nodules pulmonaires sur des examens scanographiques multicoupes du thorax.

OBJECTIVES: Evaluate the improvement in detecting lung nodules when using multidetector CT (MDCT) computer-assisted diagnosis (CAD). MATERIAL AND METHODS: Three radiologists (R1, R2, R3) with different levels of experience independently interpreted 30 MDCT examinations of the thorax taken for screening purposes, first without and then with CAD. The diagnosis was established by two of the three radiologists interpreting the images together, assisted by the CAD. RESULTS: The consensus reading identified 133 nodules, 61 (46%) of which were 4 mm or larger. The sensitivity values in the detection of nodules before and after using the CAD were 54% and 80% (R1), 38% and 71% (R2), and 70% and 88% (R3), respectively. When considering only the nodules that were 4 mm or larger, the sensitivity values varied before and after using the CAD, from 62% to 95% (R1), from 41% to 84% (R2), and from 74% to 92% (R3). By combining two by two the three radiologists' results obtained without the CAD, the sensitivity values were 65%, 83%, and 77%, respectively, for all the nodules, and 70%, 85%, and 77% for the nodules that were 4 mm or larger. The CAD induced a total of 105 false-positive results, with a mean of 3.5 per examination. CONCLUSION: The lung nodules missed by the radiologist can be detected if the CAD is used as a second reader. The CAD can be at least as beneficial as the use of a second independent reader.

Quantification of ultrasound contrast agent response: comparison of continuous wave Doppler and power Doppler to backscattered radiofrequency data.

Our goal was to compare two quantification methods of ultrasound contrast agents available in clinical practice [continuous wave Doppler intensity (CWDI) and power Doppler intensity (PWDI)] to the reference technique (radio-frequency analysis) with a simple recirculating flow phantom using a renal dialysis cartridge. Measurements were made at different doses of perflenapent emulsion and BR1. Cineloops of power Doppler images were recorded using a clinically available ultrasound unit (HDI 3000). Simultaneously, integrated backscatter (IBS) was measured by analysis of radiofrequency signals, whereas Doppler signal intensity was measured with a continuous wave Doppler device. A linear relationship was found between CWDI and IBS and between PWDI and IBS when R(2) was calculated for each pair of parameters injection-by-injection. Results are summarized by the average R(2) for all injections between CWDI and IBS (BR1: R(2) = 0.93 +/- 0.05, perflenapent emulsion: R(2) = 0.94 +/- 0.03) and between PWDI and IBS (BR1: R(2) = 0.88 +/- 0.07, perflenapent emulsion: R(2) = 0.79 +/- 0.09). However, for all data obtained from all different injected doses and for both contrast agents, there was considerable variation of CWDI and PWDI values measured for a given value of IBS. In conclusion, for a fixed microbubble population, CWDI and PWDI can be proposed for quantification of USCA. However, their important variations observed at each dose make it difficult to link a single value of PWDI or CWDI or IBS to a single microbubble distribution composition.

[Infected aneurysm of abdominal aorta: early CT finding]. / Anévrisme infectieux de l'aorte abdominale: un aspect TDM précoce.

Infected abdominal aortic aneurysm is an uncommon but life-threatening disease, especially in case of salmonella infection. Early CT findings should be well known in order to allow immediate diagnosis and accurate management. The authors present an early CT finding of a salmonella infected aneurysm of abdominal aorta in an HIV-infected patient. This pattern consists in a slight-enhancing focal densification of periaortic soft-tissue, while aorta remains of normal size. Within two weeks, infection progressed to the constitution of an infected aneurysm. This CT finding seems to be initial to previously described signs.

Evaluation of air trapping at CT: comparison of continuous-versus suspended-expiration CT techniques.

PURPOSE: To compare thin-section computed tomographic (CT) scans obtained during suspended end expiration with helical CT scans obtained during continuous expiration for the assessment of air trapping. MATERIALS AND METHODS: Forty-nine patients with an airway disease were examined with suspended-end-expiration CT after a 6-8-second expiratory maneuver, which was followed with continuous-expiration CT during a 10-second expiratory maneuver. The extent of expiratory air-trapping areas was calculated by two observers by using a semiquantitative grid score. The relative decrease in attenuation in the areas of air trapping was evaluated with a visual continuous-scale score. RESULTS: Air trapping was noted in 36 and 35 patients with continuous-expiration CT and with suspended-end-inspiration CT, respectively. The extents of and relative attenuation decreases in air-trapping areas in patients with air-trapping areas on at least one expiratory CT scan increased significantly in scans obtained with continuous-expiration CT compared with those obtained with suspended-end-expiration CT, respectively, with mean extent scores of 0.24 +/- 0.20 (SD) and 0.18 +/- 0.20 (paired t test, P: =.001) respectively, and with mean relative contrast decrease scores of 0.35 +/- 0.23 and 0.27 +/- 0.23 (paired t test, P: =.007), respectively. CONCLUSION: When suspended-end-expiration CT images are ambiguous, complementary continuous-expiration CT can be used to improve the conspicuity and apparent extent of air trapping.

Transjugular versus percutaneous renal biopsy for the diagnosis of parenchymal disease: comparison of sampling effectiveness and complications.

PURPOSE: To compare the effectiveness and safety of transjugular renal biopsy with those of percutaneous renal biopsy for diagnosis of renal parenchymal disease. MATERIALS AND METHODS: Results and complications of 400 consecutive transjugular renal biopsies performed between 1993 and 1998 with a modified Colapinto transjugular hepatic biopsy system were compared retrospectively with those of 400 percutaneous renal biopsies performed during the same period. Transjugular renal biopsy was associated with 14 cardiac and 35 hepatic biopsies. Number of glomeruli per tissue core, adequacy of tissue core for histopathologic diagnosis, and rate and severity of complications were analyzed. RESULTS: Renal tissue was obtained with percutaneous renal biopsy in 382 (95.5%) of 400 patients and with transjugular renal biopsy in 383 (95.8%) of 400 patients. The mean numbers of intact glomeruli per tissue core with optical microscopy were 11.2 +/- 7.7 (SD) and 9.8 +/- 7.6 for percutaneous renal biopsy and transjugular renal biopsy, respectively. With immunofluorescent microscopy, the mean numbers were 6.4 +/- 5.3 and 4.6 +/- 4.6 for percutaneous renal biopsy and transjugular renal biopsy, respectively. Tissue cores were adequate for histopathologic diagnosis in 98.2% with both techniques. Major complications occurred with transjugular renal biopsy in four patients and with percutaneous renal biopsy in three patients. CONCLUSION: Use of transjugular renal biopsy provides diagnostic yield and safety similar to those of percutaneous renal biopsy and allows multiorgan biopsy during the same procedure. It can be recommended in patients with percutaneous renal biopsy contraindication or failure.