Preoperative evaluation of small bowel complications in Crohn's disease: comparison of diffusion-weighted and contrast-enhanced MR imaging.

PURPOSE: To compare the accuracy of MR enterography (MRE) using combined T2-weighted and contrast-enhanced (CE) sequences with that of combined T2- and diffusion-weighted (DW) sequences for the detection of complex enteric Crohn's disease (CD). MATERIALS: Thirty-eight patients who underwent surgery for CD complications and preoperative MRE from 2011 to 2016 were included. MRE examinations were blindly analyzed independently by one junior and one senior abdominal radiologist for the presence of fistula, stenosis and abscesses. During a first reading session, T2-weighted images (WI), steady-state sequences and DW-MRE were reviewed (set 1). During a separate distant session, T2-WI, True-FISP and CE-MRE were reviewed (set 2). Performance of each reader was evaluated by comparison with the standard of reference established using intraoperative and pathological findings. RESULTS: Forty-eight fistulas, 43 stenoses and 11 abscesses were found. For the senior radiologist, sensitivity for the detection of fistula, stenosis and abscess ranged from 80% to 100% for set 1 and 88% to 100% for set 2 and specificity ranged from 56% to 70% for set 1 and 53% to 93% for set 2, with no significant difference between the sets (p = 0.342-0.429). For the junior radiologist, sensitivity ranged from 53% to 63% for set 1 and 64% to 88% for set 2 and specificity ranged from 0% to 25% for set 1 and 17% to 40% for set 2 (p = 0.001 and 0.007, respectively). CONCLUSION: For a senior radiologist, DW-MRE has similar sensitivity as CE-MRE for the detection of CD complications. For a junior radiologist, CE-MRE yields the best results compared with DW-MRE. KEY POINTS: • For experienced readers, DWI has similar diagnostic capability as contrast-enhanced MR imaging for the diagnosis of Crohn's disease complications. • For senior radiologists, gadolinium chelate injection could be waived for the diagnosis of Crohn's disease complications. • The interpretation of DWI for Crohn's disease complications requires some experience.

Accuracy of imaging for predicting operative approach in Crohn's disease.

BACKGROUND: The aim of this study was to assess the accuracy of preoperative imaging in detecting the extent of disease and predicting the operative approach in patients with Crohn's disease. METHODS: Patients with Crohn's disease who were scheduled to undergo operation were evaluated before operation using computed tomography enteroclysis (CTE) and magnetic resonance enterography (MRE). Preoperative imaging findings were correlated with intraoperative and pathological findings to estimate the capabilities of preoperative imaging in detecting lesions due to Crohn's disease. The operative approach determined before surgery was compared with the procedure actually performed, which was based on intraoperative findings. RESULTS: Fifty-two patients with Crohn's disease were studied; 26 were evaluated before surgery with CTE and 26 with MRE. Eighty-nine lesions due to Crohn's disease were confirmed surgically (60 small bowel stenoses, 21 fistulas and 8 abscesses). CTE confirmed the presence of 38 of 41 lesions (sensitivity 93 per cent) and MRE 48 of 48 lesions (sensitivity 100 per cent); a correct estimation of the disease with an exact prediction of the operative approach was obtained in 49 (94 per cent) of 52 patients. Discrepant findings between preoperative imaging and operative findings were observed in three patients (6 per cent), who had CTE. CONCLUSION: Preoperative imaging using CTE or MRE is highly accurate for assessing Crohn's disease lesions before operation, allowing correct prediction of the operative approach.

Accuracy of computed tomographic colonography in a nationwide multicentre trial, and its relation to radiologist expertise.

OBJECTIVE: Reports on the accuracy of computed tomographic colonography (CTC) mainly involve series from expert institutions. The aims of this study were to assess CTC accuracy in a nationwide population and to relate it to radiologist performance in their initial training. DESIGN: Nationwide multicentre trial. SETTING: Twenty-eight radiologists, working in 26 mostly academic clinical units, were involved in the study after having attended a formal specialised 2-day training session on CTC. They worked through a training set of 52 cases with automatic feedback after an attempt at each case. PATIENTS: The study enrolled 845 patients with average and high risk of colorectal cancer, 737 of whom had both complete CTC and videocolonoscopy data, which constituted the dataset. INTERVENTIONS: Patients underwent same-day CTC followed by videocolonoscopy with segmental unblinding of CTC results. MAIN OUTCOME MEASURES: Sensitivity, specificity and positive and negative predictive values for detection of polyps ≥ 6 mm in per-patient and per-lesion analyses of CTC without computer-aided detection. RESULTS: Sensitivity, specificity and positive and negative predictive values for patients with polyps ≥ 6 mm were 69% (95% CI 61% to 77%), 91% (95% CI 89% to 94%), 67% (95% CI 59% to 74%) and 92% (95% CI 90% to 94%), respectively. Univariate analysis showed that the detection rate for polyps ≥ 6 mm was linked to neither radiologist case volume nor number of polyps, but was related to sensitivity achieved in the training set. Pooled sensitivity was 72% (95% CI 63% to 80%) versus 51% (95% CI 40% to 60%) for radiologists achieving above and below median sensitivity in the training set (61%), respectively. Multivariate analysis showed that sensitivity for polyps ≥ 6 mm in the training set was the only remaining significant predictive factor for subsequent performance. CONCLUSIONS: Radiologist sensitivity CTC for detection of polyps ≥ 6 mm in training was the sole independent predictor for subsequent sensitivity in detection of such polyps.

[Management of ileal stenosis in patients with Crohn's disease]. / Prise en charge des sténoses iléales de maladie de Crohn.

Stenosis is the most frequent complication during Crohn's disease. The lesion can be inflammatory, or due to a fibrosing or neoplastic process. The medical treatment with anti-inflammatory drugs is usually sufficient as first line treatment; fibrous lesions require endoscopic or surgical procedures while neoplastic lesions require surgery. A multidisciplinary approach (radiologic, medical, surgical and endoscopic) is needed. In a first part, we discuss the definition of stenosis and the modalities of imaging (particularly MRI) and of treatment (particularly with TNFalpha antagonists). Then we expose the strategy for the management of the most frequent clinical situations: occlusion, ileal inflammatory stenosis, stenosis of an ileocolonic anastomosis and chronic fibrous stenosis. The treatment decision takes into account the results of radiological assessment, CRP level and the effects of the previous treatments.

[Imaging of gastrointestinal stromal tumors]. / Imagerie des tumeurs stromales digestives.

Gastrointestinal stromal tumors (GIST) arising from interstitial cells of Cajal, represent the first type of solid tumor, which is very sensitive to a specific molecularly targeted tyrosine kinase receptor blocker (i. e., imatinib). On CT, which is considered as the reference technique, GISTs typically present as large, well-delineated, heterogeneous and sometimes exophytic masses. In contrast with the absence of lymph node involvement, hepatic metastasis as well as mesenteric involvement can be observed. MR-enteroclysis is indicated to investigate the local extent of the disease in specific cases whereas MR imaging is used to detect hepatic metastasis. Because of a specific treatment, contrast-enhanced imaging is needed for the follow-up of treated tumors. Evaluation of tumor response to treatment is best assessed with CT which still remains the reference imaging technique whereas FDG-PET imaging is used in specific cases.

[Gastrointestinal stromal tumors: role of computed tomography before and after treatment]. / Tumeurs stromales digestives: rôle de la tomodensitometrie avant et apres traitement.

Gastrointestinal stromal tumors (GIST) are the most frequent mesenchymal tumors of the gastrointestinal tract. They are generally located in the stomach or the small bowel and the potential for becoming malignant varies. Due to their expression of c-kit protein, a positive diagnosis as well as a specific targeted treatment by molecular biology (imatinib) are available. Computed tomography is the best imaging method for diagnosis, staging and follow-up of GIST. They appear as a well-defined exophytic mass with heterogeneous enhancement after intravenous injection of iodinated contrast material. They may contain areas of necrosis and/or haemorrhage and enlarged lymph nodes are exceedingly rare. Most common metastatic sites are the liver and mesentery. Large tumour size and liver or mesenteric metastases are computed tomography criteria for a high malignant potential. After treatment, decrease in tumour size, number and density of lesions and the disappearance of enhancing nodules suggest a positive response to imatinib therapy, whereas a new enhancing nodule within a mass is the usual pattern of recurrence. Positron emission tomography may be useful in specific cases when clinical data are inconsistent with computed tomography criteria.

[Percutaneous abdominopelvic interventional procedures using real-time CT fluoroscopy guidance at 21 mAs: an analysis of 99 consecutive cases]. / Procédures interventionnelles percutanées abdominales et pelviennes sous contrôle TDM à l'aide d'un système de guidage fluoroscopique intégré à 21 mA: analyse de 99 cas.

PURPOSE: The purpose of our study was to retrospectively evaluate the efficacy, the limitations and the complications of real-time CT fluoroscopy (Carevision) as an adjunct to CT guidance for percutaneous abdominopelvic interventional procedures. Materials and methods. During a 28 month period, 99 patients (55 men, 44 women) with a mean age of 59 years had percutaneous abdominopelvic interventional procedure under CT guidance using CT fluoroscopy. Sixty-four patients had a percutaneous drainage of an abdominopelvic fluid collection with a Seldinger technique using an 8.5- to 14-F drainage catheter and 35 patients had a percutaneous biopsy using an 18-G automatic core biopsy needle. RESULTS: In all cases, the quality of the real-time CT fluoroscopic images allowed to securely monitor needle advancement towards the target lesion and to confirm correct position of the needle tip. The diameters of target lesions ranged from 1.5 to 10 cm, with a mean value of 4.75 cm. No immediate complications were observed. The real-time CT fluoroscopy times ranged from 25 to 242 sec, with a mean time of 117 sec. All percutaneous procedures (100%) were successfully performed. CONCLUSION: Our initial clinical experience suggests that real-time CT fluoroscopy allows to perform effective and secure percutaneous abdominopelvic interventional procedures. However, because of substantial radiation exposure, its use has to be limited to specific et selected cases.

[Linear or bubbly: a pictorial review of CT features of intestinal pneumatosis in adults]. / Linéaire ou kystique: une revue iconographique des aspects tomodensitométriques de la pneumatose intestinale de l'adulte.

Pneumatosis intestinalis is a rare condition, which is defined by the presence of gas within the bowel wall. In adult patients, pneumatosis intestinalis can be depicted in various circumstances. Owing to the routine use of CT to investigate patients with abdominal pain, pneumatosis intestinalis can be seen as an incidental finding or can be observed in association with a life-threatening disease such as bowel infarction. On CT images, pneumatosis intestinalis can display two different appearances; one that has a cystic or bubbly appearance can be considered as a chronic pneumatosis and is suggestive for a benign cause while the other, which has a linear appearance can be considered as a symptom and is more frequently secondary to a life-threatening cause. However, none of these two CT characteristics can be considered pathognomonic for any of these two categories of causes. In such situations, the analysis of the location, extent and, if any, associated findings may help to differentiate between benign and life-threatening causes. In these patients who present with abdominal signs that mimic symptoms that would warrant surgical exploration, the analysis of associated findings is critical to rule out a life-threatening cause of pneumatosis intestinalis and to obviate the need for unnecessary laparotomy. In adult patients with a known specific disease such as celiac disease, chronic pseudointestinal obstruction or other chronic diseases, even with accompanying pneumoperitoneum, pneumatosis intestinalis does not uniformly mandate surgical exploration. This pictorial review presents the more and the less common pneumatosis intestinalis CT features in adult patients, with the aim of making the reader more familiar with this potentially misleading sign.

Mass-forming lesions of the duodenum: A pictorial review.

Recent advances in imaging have resulted in marked changes in the investigation of the duodenum, which still remains primarily evaluated with videoendoscopy. However, improvements in computed tomography (CT) and magnetic resonance (MR) imaging have made detection and characterization of duodenal mass-forming abnormalities easier. The goal of this pictorial review was to illustrate the most common conditions of the duodenum that present as mass-forming lesions with a specific emphasis on CT and MR imaging. MR imaging used in conjunction with duodenal distension appears as a second line imaging modality for the characterization of duodenal mass-forming lesions. CT remains the first line imaging modality for the detection and characterization of a wide range of duodenal mass-forming lesions.

[Percutaneous drainage of abdomino-pelvic collections. Indications, techniques, and results]. / Drainage percutané des collections abdomino-pelviennes extra-parenchymateuses.

Extra-parenchymal collections in the abdomen and pelvis are a not infrequent occurrence in gastrointestinal pathologies. Twenty years of experience have proved percutaneous drainage to be a safe and effective therapeutic modality. Several studies have demonstrated the efficacy of radio-guided percutaneous drainage which can serve as a substitute for open surgical drainage in 70% of cases. This therapeutic modality should be considered for every case of abdomino-pelvic collection.

Diffusion-weighted magnetic resonance imaging in colorectal cancer.

Magnetic resonance imaging (MRI) plays now a major role in patients with colorectal cancer regarding tumor staging, surgical planning, therapeutic decision, assessment of tumor response to chemoradiotherapy and surveillance of rectal cancer, and detection and characterization of liver or peritoneal metastasis of colorectal cancers. Diffusion-weighted MRI (DW-MRI) is a functional imaging tool that is now part of the standard MRI protocol for the investigation of patients with colorectal cancer. DW-MRI reflects micro-displacements of water molecules in tissues and conveys high degrees of accuracy to discriminate between benign and malignant colorectal conditions. Thus, in addition to morphological imaging, DW-MRI has an important role to accurately detect colorectal neoplasms and peritoneal implants, to differentiate benign focal liver lesions from metastases and to detect tumor relapse within fibrotic changes. This review provides a comprehensive overview of basic principles, clinical applications and future trends of DW-MRI in colorectal cancers.

The presence of cardiophrenic angle lymph nodes is not an indicator of peritoneal carcinomatosis from colorectal cancer on MDCT: Results of a case-control study.

OBJECTIVE: To determine if the presence of cardiophrenic angle lymph nodes (CPALNs) on multidetector-row computed tomography (MDCT) can be considered as an indicator of peritoneal carcinomatosis (PC) in patients with colorectal cancer (CRC). MATERIAL AND METHODS: Two groups of 101 patients each were retrospectively included. Group 1 included patients with PC from CRC and Group 2 included patients with CRC without PC. MDCT examinations were analyzed by two readers working in consensus for the presence or absence of CPALNs and, when present for their dimensions (short and long axis), location (right, left or bilateral) and shape (oval or rounded). RESULTS: Prevalence of CPALNs was 29% in Group 1 and 32% in Group 2. No differences in prevalence of CPALNs were found between the two groups (P = 0.458). Presence of CPALNs had a sensitivity of 29% (95%CI: 23-35%) for the diagnosis of PC and a specificity of 68% (95%CI = 62-74%). No differences in CPALN dimensions, location and shape were found between these two groups. CONCLUSION: Presence of CPALNs cannot be considered as an indicator of PC in patients with CRC. In addition, when present, CPALNs have similar dimensions, location and shapes in patients with PC from CRC than in those without PC.

[CT-Guided transgluteal approach for percutaneous drainage of pelvic abscesses: results in 21 patients]. / Drainage percutané par voie postérieure transglutéale des abcès pelviens sous contrôle tomodensitométrique: analyse de 21 cas.

OBJECTIVE: Percutaneous drainage of pelvic abscesses may be challenging using a conventional anterior route because of overlying intestinal or vascular structures. Although, the posterior transgluteal route is not commonly performed, it may provide a safer approach when the conventional anterior route is not feasible. We retrospectively analyzed our experience in transgluteal percutaneous drainage of pelvic abscesses in 21 patients to determine the feasibility, safety, tolerance and efficacy of this technique. METHODS: The data of 21 patients with pelvic abscesses (15 postoperative and 6 secondary to diverticulitis) who were treated by CT-guided percutaneous transgluteal drainage between 1992 and 2002 were reviewed. Transgluteal drainage was considered as failure in case of persisting clinical sepsis, recurrence of abscess or when surgery was needed. RESULTS: The procedure was well tolerated in all patients. No major complication was observed. In one patient mild hematoma of the piriform muscle was noticed on postprocedure CT scan but did not require a specific treatment. Successful drainage as documented by follow-up CT examination was observed in 20 patients (20/21; 95%). One case of recurrence which was successfully treated by repeated percutaneous transgluteal drainage was observed in our series. CONCLUSION: Percutaneous imaging-guided transgluteal drainage is a feasible, safe, well-tolerated and effective method for the treatment of pelvic abscess when a conventional anterior route is not feasible.

Gastrointestinal stenting: Current status and imaging features.

The use of stents in the gastrointestinal tract has been subjected to major changes. Initially, the use of stents was restricted to malignant strictures in patients with metastatic disease. But thanks to reduction of the morbidity and mortality rates, they are now used with curative intention and in patients with benign diseases after careful selection. However, for patients presenting with colon obstruction due to an advanced colon carcinoma, the mortality and morbidity are still high. The purpose of this review is to provide an overview of indications, techniques and further developments of the stents in the gastrointestinal tract and to highlight the predominant role of multidetector row computed tomography (MDCT) in the detection of potential complications.

Major complications due to transjugular liver biopsy: Incidence, management and outcome.

PURPOSE: The purpose of this study was to retrospectively evaluate the incidence of intraperitoneal bleeding and other major complications of transjugular liver biopsy (TJLB) and analyze their outcome and management. MATERIALS AND METHODS: The clinical files of 341 consecutive patients who had TJLB were retrospectively analyzed. There were 237 men and 104 women (mean age: 51.38±12.8 years; range: 17-89 years). All patients had TJLB because standard percutaneous transhepatic biopsy was contraindicated. Patients' files were reviewed to search for major and minor procedure-related complications during or immediately after TJLB. RESULTS: TJLBs were technically successful in 331/341 patients (97.07%; 95%CI: 94.67-98.58%). Major complications consisted exclusively of intraperitoneal bleeding due to liver capsule perforation and were observed in 2/341 patients (0.59%; 95%CI: 0.07-2.10%). They were treated using transcatheter arterial or venous embolization with a favorable outcome. The most frequent minor complications were abdominal pain (35/341; 10.26%; 95%CI: 7.25-13.99%) and supraventricular arrhythmia (15/341; 4.40%; 95%CI: 2.48-7.15%). No cases of inadvertent injury of the carotid artery were observed. CONCLUSION: Major complications during TJLB are extremely rare and can be managed using arterial or venous embolization with a favorable outcome. Our results reinforce the general assumption that TJLB is a safe and well-tolerated technique.

MDCT and MR imaging of the jejunum.

Recent refinements in cross-sectional imaging have dramatically modified the investigation of the jejunum. Improvements in multidetector row computed tomography (MDCT) and magnetic resonance (MR) imaging technology have made detection and characterization of jejunal abnormalities easier. Current options include MDCT and MR imaging using either enterography or enteroclysis. The goal of this pictorial review is to outline the current imaging techniques that are used to investigate the jejunum and illustrate the most common conditions that affect this small bowel segment with a specific focus on MDCT and MR imaging using enterography or enteroclysis. MR imaging used in conjunction with optimal jejunal distension appears as the modality of choice for the diagnosis of a wide range of jejunal abnormalities. MDCT remains the first line imaging modalities because of an acute presentation in a substantial number of patients.

MDCT of acute colitis in adults: an update in current imaging features.

Acute colitis is often diagnosed on multidetector row computed tomography (MDCT) because patients with this condition present with abdominal pain and a variety of nonspecific symptoms. Acute colitis has multiple causes with varying degrees of severity. Analysis of the extent of colonic involvement, presence of specific MDCT imaging features and associated signs should help radiologist narrow the diagnosis. Integrating the results of clinical examination and biological tests is mandatory, and in case of ambiguous or nonspecific MDCT findings, endoscopy and colon biopsy should always be considered for a definite diagnosis. The purpose of this review is to discuss and illustrate MDCT features that are helpful for characterizing acute colitis in adults and to provide an update in current MDCT features.

Three-dimensional MDCT angiography of splanchnic arteries: pearls and pitfalls.

Fast scanning along with high resolution of multidetector computed tomography (MDCT) have expanded the role of non-invasive imaging of splanchnic arteries. Advancements in both MDCT scanner technology and three-dimensional (3D) imaging software provide a unique opportunity for non-invasive investigation of splanchnic arteries. Although standard axial computed tomography (CT) images allow identification of splanchnic arteries, visualization of small or distal branches is often limited. Similarly, a comprehensive assessment of the complex anatomy of splanchnic arteries is often beyond the reach of axial images. However, the submillimeter collimation that can be achieved with MDCT scanners now allows the acquisition of true isotropic data so that a high spatial resolution is now maintained in any imaging plane and in 3D mode. This ability to visualize the complex network of splanchnic arteries using 3D rendering and multiplanar reconstruction is of major importance for an optimal analysis in many situations. The purpose of this review is to discuss and illustrate the role of 3D MDCT angiography in the detection and assessment of abnormalities of splanchnic arteries as well as the limitations of the different reconstruction techniques.