Clare Roche

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.

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.

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-Hodgkins lymphoma (NHL) of various subtypes. No cases of Hodgkins 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.

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 Wilcoxons test. Differences between rates of lesion detection and characterization (e.g., ulceration, stricturing) were analyzed with a paired Students 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.

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.

CT evaluation of Chamberlain's, McGregor's, and McRae's skull-base lines

AIM To evaluate the mean distance from the odontoid process of C2 to the standard skull-base lines (Chamberlains, McGregors, and McRaes lines) on computed tomography (CT) imaging. To compare these measurements to previously documented plain radiograph and magnetic resonance imaging (MRI) measurements. MATERIALS AND METHODS Reformatted midline sagittal CT images of 150 adults were retrospectively evaluated. The shortest perpendicular distance was measured from the Chamberlains, McGregors and McRaes baselines for each subject to the odontoid tip. Statistical analysis was performed to compare the CT data with the previously obtained MRI and plain film data. RESULTS The mean position of the odontoid process was 1.4mm below Chamberlains line (median 1.2 mm, SD 2.4 mm), 0.8 mm (median 0.9 mm, SD 3 mm) below McGregors line and 5 mm (median 5 mm, SD 1.8 mm) below McRaes line. There is no significant difference between male and female results (p>0.05) or between these CT and previous MRI measurements (p>0.05). CONCLUSION These results provide the mean and range of normal distance from the odontoid process to the most frequently used skull-base lines on the current population on CT.

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.

Imaging of the gastrointestinal complications of systemic chemotherapy

Gastrointestinal complications of chemotherapy may be serious and potentially life-threatening. Familiarity with and awareness of the potential complications associated with various chemotherapeutic agents/regimens is paramount to enable accurate and timely diagnosis. In this article we review the radiological manifestations of the most notable gastrointestinal complications associated with chemotherapeutic administration.

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

ObjectiveTo 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).MethodsOver 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.ResultsSimultaneous 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).ConclusionSmall 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.

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.