Does MRI with oral contrast medium allow single-study depiction of inflammatory bowel disease enteritis and colitis?

OBJECTIVE: To assess the feasibility and utility of magnetic resonance (MR) imaging of the bowel in concurrent small- and large-bowel evaluation for the presence of inflammatory bowel disease (IBD). METHODS: Over a 5-year period, 62 MR examinations performed on 53 patients demonstrated evidence of IBD. Sixteen of these 53 (30.1%) patients had imaging findings of colonic disease and underwent 19 formal MR small bowel examinations. These were further evaluated for bowel distention and image quality. The sensitivity and specificity of the technique compared with colonoscopy as the 'gold standard' was evaluated. RESULTS: Simultaneous imaging of the colon is feasible at MR small bowel follow-through with moderate-to-excellent colonic visibility and colon distention obtained when the contrast medium is present in the colon at the time of image acquisition. MR imaging had a sensitivity of 80% (0.56-0.93), specificity of 100% (0.77-1.00), positive predictive value (PPV) of 1 and a negative predictive value (NPV) of 0.8 for the identification of colitis (based on available concurrent correlation of 38/62 examinations with colonoscopy). CONCLUSION: Small and large bowel MR imaging with orally consumed contrast medium represents a promising, feasible, non-invasive, non-radiating single mode of assessment of the entire gastrointestinal tract, performed at a single sitting.

The urachus revisited: multimodal imaging of benign & malignant urachal pathology.

The urachus is a fibrous tube extending from the umbilicus to the anterosuperior bladder dome that usually obliterates at week 12 of gestation, becoming the median umbilical ligament. Urachal pathology occurs when there is incomplete obliteration of this channel during foetal development, resulting in the formation of a urachal cyst, patent urachus, urachal sinus or urachal diverticulum. Patients with persistent urachal remnants may be asymptomatic or present with lower abdominal or urinary tract symptoms and can develop complications. The purpose of this review is to describe imaging features of urachal remnant pathology and potential benign and malignant complications on ultrasound, CT, positron emission tomography CT and MRI.

Hypotonic MR duodenography with water ingestion alone: feasibility and technique.

To date, cross-sectional imaging of the duodenum has a number of inadequacies, most likely a reflection of its tortuous and complex anatomical course, resulting in somewhat suboptimal imaging. The purpose of this study was to describe and assess the feasibility of performing a 'tubeless', per-oral, single contrast, hypotonic magnetic resonance (MR) duodenography technique. Secondly, to assess the efficacy of intravenous Buscopan in facilitating duodenal distension at cross-sectional MR imaging. Ten healthy volunteers prospectively underwent MR imaging of the duodenum pre- and post-Buscopan immediately after consuming 1,000 ml of water. Images were qualitatively (using a visual assessment grading scale of 1-3) and quantitatively evaluated with regard to degree of small bowel distension by two observers. The contrast medium was successfully ingested and MR examination was completed in all participants. Quantitatively and qualitatively, the per-oral, hypotonic duodenography technique yielded superior distension scores and was significantly greater in diameter in comparison with the per-oral non-hypotonic duodenography technique (p < 0.003, p < 0.002). Per-oral, single-contrast, hypotonic MR duodenography is a feasible, simple, fast mode of investigation of the duodenum, which does not involve radiation and represents a useful technique in the armamentarium of the radiologist.

MR small-bowel follow-through for investigation of suspected pediatric small-bowel pathology.

OBJECTIVE: The purpose of our study was to evaluate the potential role of an MR small-bowel follow-through (SBFT) technique in the investigation of suspected pediatric small-bowel abnormalities. MATERIALS AND METHODS: Between September 2003 and January 2008, 280 MR SBFT examinations were performed for investigation of known or suspected small-bowel abnormalities, including 19 of 280 examinations in 17 children (mean age, 13 years; age range 6-17 years), representing the current study population. A standardized technique was used in all cases, including axial and coronal steady-state free precession acquisitions at successive time intervals until completion. Retrospective analysis of the studies obtained was performed by two radiologists, who blindly and independently scored predefined small-bowel segments according to the degree of luminal distention achieved. Any pathologic lesions detected were also noted. Indicators of examination success as a whole (volume, tolerability, and side effects of oral contrast material) were also noted, as were details pertaining to examination duration (number of visits to the MR table, total table time). RESULTS: Oral contrast medium was ingested and subsequent imaging was possible in all patients; 84.2% of patients tolerated the oral contrast material well and 15.8% showed moderate tolerance. The MR table time ranged from 2 to 4 minutes, without early termination of the examination in any case. The average number of visits to the MR table was 1.3 (range, 1-3). The mean duration for complete small-bowel evaluation was 25 minutes (range, 20-60 minutes). The mean distention scores were well within the diagnostic range in all small-bowel segments for both observers, with a substantial degree of interobserver agreement in score assignment (kappa = 0.73). Pathologic lesions were identified in 53% of studies. CONCLUSION: MR SBFT represents a promising, and perhaps optimal, technique for pediatric small-bowel evaluation for a variety of reasons, including its high tolerability, lack of ionizing radiation, avoidance of duodenojejunal intubation, and excellent luminal distention achieved. Furthermore, this technique allows "pseudodynamic" functional imaging while also showing extraluminal disease, without known biologic risk.

Perforated Meckel's Diverticulum Masquerading as a Mesenteric Abscess Related to Umbilical Piercing: An Unusual Cause of Acute Abdomen.

Perforated Meckel's diverticulum (MD) is a rare cause of acute abdomen in adults. We describe the case of a 32-year-old man presenting with worsening abdominal pain three weeks following the piercing of his umbilicus. Computed tomography of the abdomen and pelvis demonstrated a small mesenteric collection intimately related to the recently placed navel ornamentation, and a preliminary diagnosis of intra-abdominal abscess secondary to an infected umbilical piercing was made. Initial conservative management with antibiotic therapy was unsuccessful. Subsequent open surgical approach demonstrated an inflamed, perforated Meckel's diverticulum with a small, adjacent infected collection separate from, but in close proximity to the belly-button foreign body. The patient was successfully treated with small bowel resection and followed an uneventful postoperative course.

Duodenal abnormalities at MR small-bowel follow-through.

OBJECTIVE: The cross-sectional characterization of duodenal abnormalities is plagued with inadequacy, a reflection of the meandering course of this segment of the bowel. We consider the imaging appearance of such abnormalities at MRI small-bowel follow-through, illustrating the typical manifestations of each pathologically confirmed condition. CONCLUSION: MRI small-bowel follow-through allows confident duodenal evaluation because of a combination of sufficient luminal distention and multiplanar versatility. Diseases of the duodenum may have a variety of manifestations at MRI small-bowel follow-through, the knowledge of which may aid in confident noninvasive patient diagnosis.

MR enterography of small-bowel lymphoma: potential for suggestion of histologic subtype and the presence of underlying celiac disease.

OBJECTIVE: The objective of our study was to evaluate the morphologic appearances of small-bowel lymphoma using MR enterography to identify key morphologic traits capable of providing an association between imaging manifestations and likely histologic diagnosis. MATERIALS AND METHODS: Over a 54-month period, 10 patients with subsequently confirmed small-bowel lymphoma were imaged using a standardized MR enterography technique. Retrospective chart review was performed to detect associated disease processes, such as celiac disease. The morphologic characteristics of each segment with lymphomatous involvement were evaluated with respect to tumor location, tumor size, mural characteristics, fold features, loop dilatation, luminal stricturing, mesenteric or antimesenteric distribution, mesenteric involvement, and signal intensity. RESULTS: Nineteen distinct segments of lymphomatous involvement were identified in 10 patients, and underlying celiac disease was confirmed in six of the 10 patients. This patient group comprised 10 patients with non-Hodgkin's lymphoma (NHL) of various subtypes. No cases of Hodgkin's lymphoma were encountered. Analysis revealed celiac NHL enteropathy to have a tendency toward localization to a single, long (> 10 cm), smooth continuous bowel segment, often with aneurysmal loop dilatation, in the absence of a distinct mesenteric or antimesenteric distribution. Luminal stricturing was encountered in cases of low-grade lymphoma, whereas mesenteric fat infiltration represented a characteristic of high-grade disease. CONCLUSION: We describe the characteristics of small-bowel lymphoma on MR enterography, identifying a number of key features that may help the interpreting radiologist in suggesting the underlying histologic subtype and whether the presence of underlying celiac disease is likely.

Retroperitoneal fibrosis: a review of clinical features and imaging findings.

OBJECTIVE: Retroperitoneal fibrosis is a rare collagen vascular disorder of unclear cause. Both benign and malignant associations have been described, rendering differentiation of these entities of paramount importance because sinister pathology alters the diagnosis. Thus, a high level of diligence is required in the investigation of this condition, particularly in patients with concomitant systemic conditions. CONCLUSION: Familiarity with the realm of imaging manifestations of retroperitoneal fibrosis is vital to ensure correct diagnosis and optimal treatment.

MRI small-bowel follow-through: prone versus supine patient positioning for best small-bowel distention and lesion detection.

OBJECTIVE: The purpose of this study was to assess whether prone or supine imaging provides superior small-bowel loop distention during MRI small-bowel follow-through examinations and whether either position is better with regard to lesion detection and evaluation. SUBJECTS AND METHODS: Forty consecutively enrolled clinically referred patients with known or suspected small-bowel abnormalities prospectively underwent 62 MRI small-bowel follow-through examinations in both the prone and the supine positions. Images were blindly and independently reviewed by two observers. Each small-bowel segment was assessed with a 3-point scoring system, and differences in bowel distention in the prone and supine positions were evaluated with a paired Wilcoxon's test. Differences between rates of lesion detection and characterization (e.g., ulceration, stricturing) were analyzed with a paired Student's t test. Interobserver agreement was estimated with the kappa coefficient. RESULTS: In both normal and diseased small bowel, the prone position had statistically significantly higher distention scores than did the supine position (p < 0.05) with a high level of interobserver agreement. This finding, however, did not translate into improved lesion detection or characterization (p > 0.05). CONCLUSION: Although use of the prone position results in superior small-bowel distention during MRI small-bowel follow-through, both the prone and supine positions are equal in terms of lesion detection and feature visualization.

Prevalence and significance of asymptomatic venous thromboembolic disease found on oncologic staging CT.

OBJECTIVE: The purpose of our study was to determine the prevalence of unsuspected venous thromboembolic disease--specifically, of pulmonary embolism (PE) and of inferior vena cava (IVC), iliac, and iliofemoral deep venous thromboses (DVTs)--in oncology patients on staging CT scans of the thorax, abdomen, and pelvis. MATERIALS AND METHODS: Retrospective analysis was performed on 435 consecutive staging CT thorax, abdomen, and pelvis scans performed on a variety of oncology patients for the presence of venous thromboembolic disease. The patient group consisted of 198 men and 237 women who ranged in age from 20 to 79 years (mean, 55 years). Disease type, stage, concomitant surgery or chemoradiation therapy regimes, anticoagulation status, and 6-month clinical and radiologic follow-up findings were recorded. RESULTS: We found a prevalence of 6.8% (23/339) unsuspected iliofemoral, 1.2% (4/339) unsuspected common iliac, and 0.3% (1/315) unsuspected IVC DVTs and 3.3% (13/397) unsuspected PEs occurring in patients with a wide range of malignancies. The overall prevalence of unsuspected venous thromboembolism (i.e., DVT, PE, or both) was 6.3% (25/397). DVT, PE, and venous thromboembolic disease were more common in inpatients (p = 0.002, 0.004, 0.023; relative risk [RR] = 1.6, 2.1, 1.4, respectively) and in those with advanced disease (p = 0.001, 0.01, 0.001; RR = 2.2, 1.8, 2.0, respectively). CONCLUSION: Although there is a known increased risk of thromboembolism (DVT and PE) in oncology patients, many cases are not diagnosed, which can prove fatal. Staging CT simultaneously affords one sole investigation of the pulmonary, IVC, iliac, and upper femoral veins, thereby providing an important diagnostic opportunity. Assessment for DVT and PE is important when reviewing staging CT scans.

Atlanto-occipital dislocation: case report and discussion.

Atlanto-occipital dislocation (AOD) is a devastating condition that frequently results in prehospital cardiorespiratory arrest and accounts for 15% of fatal spinal trauma. Atlanto-occipital dislocation occurs 5 times more commonly in children than adults, and is believed to be caused by hyperextension. Because of improvements in prehospital resuscitation, more victims with AOD now survive to reach the emergency department. Neurologic injury is usually severe secondary to ligamentous disruption that allows the cranium to move with respect to the cervical spine, and associated facial and head injuries are common. There are, however, reports of survivors without neurologic deficits. We present the case of a 46-year-old woman who suffered an AOD after a motor vehicle crash and we discuss the diagnosis of this condition. The signs of AOD are often subtle, and the possibility of this diagnosis must be kept in mind in all patients with a neck injury, even in the absence of neurologic signs. A systematic approach to assessing the cranio-cervical relationship on the lateral cervical x-ray and the appropriate use of CT scanning is essential to identifying AOD. Through this case report we hope to familiarize clinicians with mechanisms of injury and appropriate imaging interpretation that will assist in the diagnosis of AOD.

Rotation of the atlantico-axial joint, investigated using CT and MRI.

The vertebral column is composed of a series of joints, each capable of a specific range of movement. To investigate these movements, a study into the physiological range of rotation at the atlanto-axial joint has been undertaken. The movements and their interpretation under imaging conditions are crucial if any underlying spinal deformity or the consequences of trauma are present in an individual. 28 healthy volunteers were examined using dynamic Magnetic Resonance Imaging with maximum head rotation to the right and left sides in turn. An anatomical specimen of the atlanto-occipital joint was imaged using Computed Tomography with the specimen fixed in varying degrees of rotation. The results indicate that there is a significant but incomplete loss of contact between the articular surfaces of C1 (atlas) and C2 (axis). The range of motion to the right was between 20 and 48.5 degrees (mean 32.4 degrees) and to the left was between 13 and 52.75 degrees (mean 3.2 degrees). Statistical significance between left and right movement was not demonstrated. The instantaneous axis of rotation was examined for the joint and was found to be located within the odontoid peg (dens). These findings indicated that a wide range of movement occurs within the atlanto-axial joint in normal subjects. Furthermore, the appearances under imaging could be misinterpreted as a pathological subluxation. This has implications if the subject with a spinal deformity also has a dysplasia associated with a potential subluxation. The siting of the instantaneous axis of rotation within the odontoid is also important in furthering the understanding of the movement of this joint.

Normal small bowel wall characteristics on MR enterography.

PURPOSE: To assess the normal small bowel parameters, namely bowel diameter, bowel wall thickness, number of folds (valvulae connivientes) per 2.5 cm (in.), fold thickness and interfold distance per small bowel segment (duodenum, jejunum, proximal ileum, distal ileum and terminal ileum) on MR enterography. MATERIALS AND METHODS: Between September 2003 and January 2008, 280 MR enterography examinations were performed for investigation of known or suspected small bowel pathology. 120 of these examinations were normal. Sixty-five (m=29, f=36, mean age=34 years, range=17-73 years) of 120 examinations without a prior small bowel diagnosis, with no prior or subsequent abnormal radiology or endoscopy examinations, no prior small bowel surgery and with a minimum 3 years follow-up demonstrating normality were retrospectively evaluated for the described small bowel parameters. RESULTS: We found the mean diameter of the duodenum to be 24.8mm (S.D.=4.5mm), jejunum to be 24.5mm (S.D.=4.2mm), proximal ileum to be 19.5mm (S.D.=3.6mm), distal ileum to be 18.9 mm (S.D.=4.2mm) and terminal ileum to be 18.7 mm (S.D.=3.6mm). The number of folds per 2.5 cm varied from 4.6 in the jejunum to 1.5 in the terminal ileum. The fold thickness varied from 2.1mm in the duodenum to 1.8mm in the terminal ileum. The small bowel parameters gradually decreased in size from the duodenum to the smallest measurements which were in the terminal ileum. The bowel wall is similar in size throughout the small bowel measuring 1.5+/-0.5mm. CONCLUSION: These results provide the mean, range of normality and standard deviation of the small bowel parameters per segment on the current population on MR enterography. From our experience, knowledge of these parameters is extremely helpful and essential in the everyday assessment of MR enterography studies.

Sacral insufficiency fracture complicated by epidural haematoma and cauda equina syndrome in a patient with multiple myeloma.

We report the case of a patient with multiple myeloma (MM) and extensive lytic bone disease who presented with a short history of back pain and leg weakness. Magnetic resonance imaging (MRI) of the lumbar spine revealed a sacral insufficiency fracture complicated by an epidural haematoma. Bleeding tendency in this case can be accounted for by platelet function defects, often described in plasma cell disorders in the absence of obvious coagulation abnormalities. Surgical intervention was contraindicated as a result of poor overall patient performance status (poor surgical candidate due to extensive myelomatous bone disease, previous vertebral compression fractures requiring orthopaedic stabilisation, and requiring opiate analgesia for bone pain) and management was conservative. Patients presenting with back pain and documented bone disease in the setting of myeloma should be managed with a high index of clinical suspicion and considered for urgent MR imaging to avoid missing this serious and potentially reversible complication. We report the undescribed causative association between sacral insufficiency fracture and lumbo-sacral epidural haematoma. We illustrate the MRI signal and contrast enhancement pattern of an acute presentation of epidural haematoma.

The rheumatoid cervical spine: signs of instability on plain cervical radiographs.

The cervical spine is a common focus of destruction from rheumatoid arthritis, second only to the metacarpophalangeal joints. Joint, bone and ligament damage in the cervical spine leads to subluxations which can cause cervical cord compression resulting in paralysis and even sudden death. Because many patients with significant subluxations are asymptomatic, the radiologist plays a key role in recognizing the clinically important clues to instability on plain radiographs of the cervical spine-often difficult in rheumatoid arthritis when the bony landmarks are osteoporotic or eroded. This review focuses on the signs of instability on plain radiographs of the cervical spine, using diagrams and clinical examples to illustrate methods of identifying significant subluxations in rheumatoid arthritis.

The atlanto-axial joint: physiological range of rotation on MRI and CT.

AIMS: To measure the range of rotation and determine the instantaneous axis of rotation of the atlanto-axial joint in healthy volunteers using magnetic resonance imaging (MRI) and to highlight the appearances of the rotated atlanto-axial joint on computed tomography (CT) and MRI. MATERIALS AND METHODS: Twenty-eight healthy volunteers were examined using MRI during maximal head rotation. In addition, an anatomical specimen of the atlanto-axial joint, fixed in varying degrees of rotation, was imaged using CT. RESULTS: At the extremes of physiological rotation in healthy subjects there is striking but incomplete loss of contact between the articular surfaces of the atlas (C1) and the axis (C2). The range of rotation to the right was 20-48.5 degrees (mean 32.4 degrees ) and to the left was 13-52.75 degrees (mean 34.2 degrees ). There was no significant difference between rotation to the right and left (P = 0.455). Total rotation was 45-88.5 degrees (mean 69.25 degrees ). The instantaneous axis of rotation was located within the odontoid peg. CONCLUSION: There is a wide range of atlanto-axial rotation in normal subjects. The instantaneous axis of rotation lies within the odontoid peg. The appearances of the rotated atlanto-axial joint are striking and may be misinterpreted as subluxation.

CT and pathologic assessment of prospective nodal staging in patients with ductal adenocarcinoma of the head of the pancreas.

OBJECTIVE: The aim of our study was to compare the assessment of peripancreatic lymph nodes using CT with the gold standard of detailed histopathologic assessment of resected specimens in patients with pancreatic ductal adenocarcinoma. SUBJECTS AND METHODS: Sixty-two patients with presumed pancreatic carcinoma were prospectively studied with dual-phase contrast-enhanced helical CT, and images were interpreted in consensus by three radiologists. Complete surgical resection was performed in 28 patients. A detailed nodal classification system was used for radiologic, surgical, and pathologic staging in the nine patients whose final diagnosis at histology was pancreatic ductal adenocarcinoma. RESULTS: Forty lymph nodes were prospectively identified on CT in these nine patients. Two of 23 nodes (9%) measuring less than 5 mm in the short-axis diameter were malignant, four of 11 nodes (36%) measuring 5-10 mm were malignant, and one of six nodes (17%) larger than 10 mm was malignant. Using a short-axis diameter of greater than 10 mm as the criterion for nodal involvement, we found a sensitivity of 14% (1/7) and a specificity of 85% (28/33), with a positive predictive value of 17% (1/6), a negative predictive value of 82% (28/34), and an overall accuracy of 73% (29/40). Ovoid nodal shape, clustering of nodes, and the absence of a fatty hilum were not useful predictors of malignancy on CT. CONCLUSION: In resectable pancreatic ductal adenocarcinoma, CT is not accurate overall for the prediction of nodal involvement. In a patient with presumed pancreatic carcinoma that is considered to be resectable, the depiction on CT of peripancreatic nodes should not prevent attempted curative resection.

Selections from the buffet of food signs in radiology.

Certain pathologic conditions have classic radiologic manifestations that resemble various types of food. These "food signs" are highly memorable and easily recognizable and include findings that resemble various fruits and vegetables; meat, fish, and egg dishes; pasta, rice, grains, and bread (carbohydrates); desserts, cakes, and candy; and dishes, cutlery, condiments, and so on. It is important that radiologists recognize these classic signs, which will allow confident diagnosis on the basis of imaging findings alone or narrowing of the differential diagnosis.