Philippe Soyer

MRI of liver metastases from colorectal cancer vs. CT during arterial portography.

A prospective study was performed to compare, with a lesion-by-lesion analysis, the sensitivities of high field strength MRI and CT during arterial portography (CTAP) in detecting hepatic metastases from colorectal cancer. Twenty-one patients with liver metastases from colorectal cancer were prospectively investigated by high field strength MRI (1.5 or 2 T) and CTAP. High field strength MRI was performed with pre and post gadopentetate dimeglumine enhanced T1-weighted SE sequences and T2-weighted SE sequences. All patients underwent partial hepatectomy and 37 metastases were surgically and pathologically proved. The metastasis detection rate (sensitivity) was 94% (35 of 37) for CTAP and 78% (29 of 37) for high field strength MRI. The 16% (95% confidence interval: 1–31%) difference in sensitivity between CTAP and high field strength MRI was statistically significant (p < 0.05, Mc-Nemar test). The use of gadopentetate dimeglumine did not improve the sensitivity of T1-weighted SE sequences. Since our study demonstrated significant difference in sensitivities between high field strength MRI and CTAP in our group of patients, we can conclude that high field strength MRI cannot replace CTAP in the preoperative evaluation of patients with liver metastases from colorectal cancer. Computed tomography during arterial portography must be considered as the preoperative gold standard. Index Terms: Liver, neoplasms—Portography—Magnetic resonance imaging, techniques.

Diffusion-weighted MR Imaging of the Pancreas: Current Status and Recommendations

Advances in image quality over the past few years, mainly due to refinements in hardware and coil systems, have made diffusion-weighted ( DW diffusion weighted ) magnetic resonance (MR) imaging a promising technique for the detection and characterization of pancreatic conditions. DW diffusion weighted MR imaging can be routinely implemented in clinical protocols, as it can be performed relatively quickly, does not require administration of gadolinium-based contrast agents, and enables qualitative and quantitative assessment of tissue diffusivity (diffusion coefficients). In this review, acquisition parameters, postprocessing, and quantification methods applied to pancreatic DW diffusion weighted MR imaging will be discussed. The current common clinical uses of DW diffusion weighted MR imaging (ie, pancreatic lesion detection and characterization) and the less-common applications of DW diffusion weighted MR imaging used for the diagnosis of pancreatic parenchymal diseases will be reviewed. Also, the limitations of the technique, mainly image quality and reproducibility of diffusion parameters, as well as future directions for pancreatic DW diffusion weighted MR imaging will be discussed. The utility of apparent diffusion coefficient ( ADC apparent diffusion coefficient ) measurement for the characterization of pancreatic lesions is now well accepted but there are a number of limitations. Future well-designed, multicenter studies are needed to better determine the most appropriate use of ADC apparent diffusion coefficient in the area of pancreatic disease.

Effectiveness of MR enterography for the assessment of small-bowel diseases beyond Crohn disease.

The use of cross-sectional imaging techniques for the noninvasive evaluation of small-bowel disorders is increasing. The effectiveness of magnetic resonance (MR) enterography for the evaluation of Crohn disease, in particular, is well described in the literature. In addition, MR enterography has an evolving though less well documented role to play in the evaluation of other small-bowel diseases, including various benign and malignant neoplasms arising in isolation or in polyposis syndromes such as Peutz-Jeghers, inflammatory conditions such as vasculitis and treatment-induced enteritis, infectious processes, celiac disease, diverticular disease, systemic sclerosis, and bowel duplication. MR enterography may be useful also for the evaluation of intermittent and low-grade small-bowel obstructions. Advantages of MR imaging over computed tomography (CT) for enterographic evaluations include superb contrast resolution, lack of associated exposure to ionizing radiation, ability to acquire multiplanar primary image datasets, ability to acquire sequential image series over a long acquisition time, multiphasic imaging capability, and use of intravenous contrast media with better safety profiles. MR enterography also allows dynamic evaluations of small-bowel peristalsis and distensibility of areas of luminal narrowing and intraluminal masses by repeating sequences at different intervals after administering an additional amount of the oral contrast medium. Limitations of MR enterography in comparison with CT include higher cost, less availability, more variable image quality, and lower spatial resolution. The advantages and disadvantages of MR enterography performed with ingestion of the oral contrast medium relative to MR enteroclysis performed with infusion of the oral contrast medium through a nasoenteric tube are less certain.

Functional evaluation of normal and ischemic kidney by means of gadolinium-DOTA enhanced TurboFLASH MR imaging: A preliminary comparison with 99mTc-MAG3 dynamic scintigraphy

The functional value of TurboFLASH MR imaging in the assessment of dynamic contrast enhancement and renal perfusion anomalies was evaluated in seven patients, who also underwent renal scintigraphy in baseline conditions. The basal renograms obtained from MAG-3 scintigraphy (mercapto acetyl triglycine, MAG3-S) and from Gd-DOTA-enhanced turboFLASH MRI were compared. After hydration, the protocol used consisted in breath-hold coronal turboFLASH acquisitions after IV bolus of Gd-DOTA (4 s every 20 s during 10 min) for MRI, and IV bolus of 370 MBq of 99mTc-MAG3 followed by 60 frames of 1 s and then 120 frames of 10 s for MAG3-S. Relative renal functions were computed for both methods by calculation of the integral of the uptake phase between the first and the second minute. Renograms exhibited 10 normal and 4 ischemic kidneys. There was a close correlation between the contrast enhancement of MRI and isotopic uptake in normal and ischemic kidneys. Global renograms of MRI correlated with MAG3-S (r = .82, p < .001) with similar curve shape and time to peak. Relative renal function of the right and left kidney were closely correlated in all patients (r = .98, p < .001), although there was a tendency for MR to overestimate MAG3-S evaluation in kidneys with severe basal dysfunction. Enhanced turboFLASH provides noninvasive assessment of renal perfusion in patients with renovascular disease. Accurate renograms are obtained with dynamic-enhanced MRI, but the relative renal function seems to be overestimated in low values of ischemic kidneys, and needs further comparative evaluation.

Can failure of percutaneous drainage of postoperative abdominal abscesses be predicted

BACKGROUND Percutaneous drainage (PD) of complex postoperative abscesses associated with a variety of factors such as multiple location or enteric fistula remains a matter of debate. Accordingly, this retrospective study was designed to determine the predictive factors for failure of PD of postoperative abscess, in order to better select the patients who may benefit from PD. METHODS From 1992 to 2000, the data of 73 patients who underwent computed tomography (CT)-guided PD for postoperative intra-abdominal abscess, were reviewed. PD was considered as failure when clinical sepsis persisted or subsequent surgery was needed. The possible association between failure of PD and 27 patient-, abscess-, surgical-, and drainage-related variables were assessed using univariate and multivariate analysis. RESULTS Successful PD was achieved in 59 of 73 (81%) patients. The overall mortality was 3% but no patient died after salvage surgery. Multivariate analysis showed that only an abscess diameter of less than 5 cm (P = 0.042) and absence of antibiotic therapy (P = 0.01) were significant predictive variables for failure of PD. CONCLUSIONS CT-guided PD associated with antibiotic therapy could be attempted as the initial treatment of postoperative abdominal abscesses even in complex cases such as loculated abscess or abscess associated with enteric fistula.

Carcinoid tumors of the abdomen: CT features

Carcinoid tumors are rare neuroendocrine neoplasms that belong to a more general category of tumor called the APUDomas. Ninety percent of carcinoid tumors are located in the gastrointestinal tract. Abdominal carcinoid tumors are categorized according to the division of the primitive gut from which they arise. Carcinoid tumors originating from the foregut develop in the gastric wall, duodenum, and pancreas; those originating from the midgut develop from the small bowel, appendix, and right colon; and those originating from the hindgut develop from the transverse or left colon or from the rectum. This report illustrates the computed tomographic appearance of primary and metastatic carcinoid tumors of the abdomen. Among the different organs that may be involved by metastases from carcinoid tumor, special emphasis is placed on the liver.

Obscure gastrointestinal bleeding: preliminary comparison of 64-section CT enteroclysis with video capsule endoscopy

ObjectiveTo retrospectively compare the diagnostic capabilities of 64-section CT enteroclysis with those of video capsule endoscopy (VCE) to elucidate the cause of obscure gastrointestinal bleeding.MethodsThirty-two patients who had 64-section CT enteroclysis and VCE because of obscure gastrointestinal bleeding were included. Imaging findings were compared with those obtained at double balloon endoscopy, surgery and histopathological analysis, which were used as a standard of reference.ResultsConcordant findings were found in 22 patients (22/32; 69%), including normal findings (n = 13), tumours (n = 7), lymphangiectasia (n = 1) and inflammation (n = 1), and discrepancies in 10 patients (10/32; 31%), including ulcers (n = 3), angioectasias (n = 2), tumours (n = 2) and normal findings (n = 3). No statistical difference in the proportions of abnormal findings between 64-section CT enteroclysis (11/32; 34%) and VCE (17/32, 53%) (P = 0.207) was found. However, 64-section CT enteroclysis helped identify tumours not detected at VCE (n = 2) and definitely excluded suspected tumours (n = 3) because of bulges at VCE. Conversely, VCE showed ulcers (n = 3) and angioectasias (n = 2) which were not visible at 64-section CT enteroclysis.ConclusionOur results suggest that 64-section CT enteroclysis and VCE have similar overall diagnostic yields in patients with obscure gastrointestinal bleeding. However, the two techniques are complementary in this specific population.

Suspected Anastomotic Recurrence of Crohn Disease after Ileocolic Resection: Evaluation with CT Enteroclysis

PURPOSE To determine the utility of computed tomographic (CT) enteroclysis for characterization of the status of the anastomotic site in patients with Crohn disease who had previously undergone ileocolic resection. MATERIALS AND METHODS Written informed consent was prospectively obtained from all patients, and the institutional review board approved the study protocol. CT enteroclysis findings in 40 patients with Crohn disease who had previously undergone ileocolic resection were evaluated independently by two readers. Endoscopic findings, histopathologic findings, and/or the Crohn disease activity index was the reference standard. Interobserver agreement between the two readers was calculated with kappa statistics. Associations between CT enteroclysis findings and anastomotic site status were assessed at univariate analysis. The sensitivity, specificity, and accuracy of CT enteroclysis, with corresponding 95% confidence intervals (CIs), for the diagnosis of normal versus abnormal anastomosis and the diagnosis of anastomotic recurrence versus fibrostenosis were estimated. RESULTS Interobserver agreement regarding CT enteroclysis criteria was good to perfect (kappa = 0.72-1.00). At univariate analysis, stratification and anastomotic wall thickening were the two most discriminating variables in the differentiation between normal and abnormal anastomoses (P < .001). Stratification (P < .001) and the comb sign (P = .026) were the two most discriminating variables in the differentiation between anastomotic recurrence and fibrostenosis. In the diagnosis of anastomotic recurrence, severe anastomotic stenosis was the most sensitive finding (95% [20 of 21 patients]; 95% CI: 76.18%, 99.88%), both comb sign and stratification had 95% specificity (18 of 19 patients; 95% CI: 73.97%, 99.87%), and stratification was the most accurate finding (92% [37 of 40 patients]; 95% CI: 79.61%, 98.43%). In the diagnosis of fibrostenosis, both severe anastomotic stenosis and anastomotic wall thickening were 100% sensitive (eight of eight patients; 95% CI: 63.06%, 100.00%), and using an association among five categorical variables, including severe anastomotic stenosis, anastomotic wall thickening with normal or mild mucosal enhancement, absence of comb sign, and absence of fistula, yielded 88% sensitivity (seven of eight patients; 95% CI: 47.35%, 99.68%), 97% specificity (31 of 32 patients; 95% CI: 83.78%, 99.92%), and 95% accuracy (38 of 40 patients; 95% CI: 83.08%, 99.39%). CONCLUSION CT enteroclysis yields objective and relatively specific morphologic criteria that help differentiate between recurrent disease and fibrostenosis at the anastomotic site after ileocolic resection for Crohn disease. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.09091165/-/DC1.

Severe postpartum haemorrhage from ruptured pseudoaneurysm: successful treatment with transcatheter arterial embolization

The purpose of this retrospective study was to evaluate the role of transcatheter arterial embolization in the management of severe postpartum haemorrhage due to a ruptured pseudoaneurysm and to analyse the clinical symptoms that may suggest a pseudoaneurysm as a cause of postpartum haemorrhage. A retrospective search of our database disclosed seven women with severe postpartum haemorrhage in whom angiography revealed the presence of a uterine or vaginal artery pseudoaneurysm and who were treated using transcatheter arterial embolization. Clinical files were reviewed for possible clinical findings that could suggest pseudoaneurysm as a cause of bleeding. Angiography revealed extravasation of contrast material in five out of seven patients. Transcatheter arterial embolization allowed to control the bleeding in all patients and subsequently achieve vaginal suture in four patients with vaginal laceration. No complications related to transcatheter arterial embolization were noted. Only two patients had uterine atony, and inefficiency of sulprostone was observed in all patients. Transcatheter arterial embolization is an effective and secure technique for the treatment of severe postpartum haemorrhage due to uterine or vaginal artery pseudoaneurysm. Ineffectiveness of suprostone and absence of uterine atony should raise the possibility of a ruptured pseudoaneurysm.

Value of pelvic embolization in the management of severe postpartum hemorrhage due to placenta accreta, increta or percreta.

OBJECTIVES To evaluate the role, efficacy and safety of pelvic embolization in the management of severe postpartum hemorrhage in women with placenta accreta, increta or percreta. METHODS The clinical files and angiographic examinations of 12 consecutive women with placenta accreta (n=4), increta (n=2) or percreta (n=6) who were treated with pelvic embolization because of severe primary (n=10) or secondary (n=2) postpartum hemorrhage were reviewed. Before embolization, four women had complete placental conservation, four had partial placental conservation, three had an extirpative approach and one had hysterectomy after failed partial conservative approach. RESULTS In 10 women, pelvic embolization was successful and stopped the bleeding, after one (n=7) or two sessions (n=3). Emergency hysterectomy was needed in two women with persistent bleeding after embolization, both with placenta percreta and bladder involvement first treated by extirpation. One case of regressive hematoma at the puncture site was the single complication of embolization. CONCLUSIONS In women with severe postpartum hemorrhage due to placenta accreta, increta or percreta, pelvic embolization is effective for stopping the bleeding in most cases, thus allowing uterine conservation and future fertility. Further studies, however, should be done to evaluate the potential of pelvic embolization in women with placenta percreta with bladder involvement.