Carmel G. Cronin

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.

Incidental Adrenal Lesions: Accuracy of Characterization with Contrast-enhanced Washout Multidetector CT—10-minute Delayed Imaging Protocol Revisited in a Large Patient Cohort

PURPOSE To reassess the accuracy of the 10-minute delayed scan to differentiate both lipid-rich and lipid-poor lesions in a large cohort of patients. MATERIALS AND METHODS This HIPAA-compliant retrospective study had institutional review board approval; the need for informed consent was waived. A multidetector computed tomography (CT) adrenal protocol (unenhanced, dynamic contrast material-enhanced, and 10-minute delayed CT) was used in 314 consecutive patients (201 women, 113 men; mean age, 63.6 years) for the period from January 2006 through February 2009. The mean adrenal attenuation during all three CT phases was measured by two readers, and the relative percentage washout (RPW) and absolute percentage washout (APW) values were calculated. APW and RPW receiver operating characteristic (ROC) analysis was performed to evaluate the strength of the tests. RESULTS There were 323 adrenal lesions (213 left, 110 right) consisting of 307 adenomas and 16 nonadenomas. The sensitivity, specificity, and accuracy for the RPW test at a washout threshold of 50% were 55.7%, 100%, and 57.9%, respectively; at 40% were 76.9%, 93.7%, and 77.7%; and at 35% were 81.4%, 93.7%, and 82.0%. The sensitivity, specificity, and accuracy for the APW test at a 60% threshold were 52.1%, 93.3%, and 54.0%, respectively; at 55% were 62.5%, 93.3%, and 64.0%; and at 50% were 71.3%, 80.0%, and 71.7%. Areas under the ROC curve were 0.85 (95% confidence interval: 0.75, 0.95) and 0.91 (95% confidence interval: 0.85, 0.97) for the APW and RPW tests, respectively, to detect adenomatous disease. CONCLUSION The 10-minute delayed adrenal enhancement washout test has reduced sensitivity for the characterization of adrenal adenomas compared with results from prior studies.

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.

Role of PET/CT in Ovarian Cancer

OBJECTIVE The purpose of this article is to review the role of FDG PET/CT in ovarian cancer, which is the leading cause of death among gynecologic cancers. CONCLUSION FDG PET/CT can significantly modify the assessment of the extent of primary and recurrent ovarian cancer and, hence, often alters patient management substantially. FDG PET/CT has thus become a critical tool for the preoperative evaluation of women with primary ovarian cancer and for postoperative follow-up assessment for evidence of recurrence in these patients.

Imaging of bone metastasis: An update

Early detection of skeletal metastasis is critical for accurate staging and optimal treatment. This paper briefly reviews our current understanding of the biological mechanisms through which tumours metastasise to bone and describes the available imaging methods to diagnose bone metastasis and monitor response to treatment. Among the various imaging modalities currently available for imaging skeletal metastasis, hybrid techniques which fuse morphological and functional data are the most sensitive and specific, and positron emission tomography (PET)/computed tomography and PET/magnetic resonance imaging will almost certainly continue to evolve and become increasingly important in this regard.

Unsuspected Pulmonary Emboli in Oncology Patients Undergoing Routine Computed Tomography Imaging

Introduction: Clinically unsuspected pulmonary embolism (PE) can be detected in oncology patients undergoing computed tomography (CT) imaging for reasons other than for PE diagnosis, but there is little prospective data on its true prevalence, clinical importance, or on methods to improve detection. Methods: In consecutive oncology patients undergoing CT imaging of the chest for indications other than PE detection, CT pulmonary angiography (CTPA) was systematically included as part of the imaging protocol. Each imaging study was prospectively analyzed for the presence of PE. A 6-month follow-up was performed. Institutional review board approval was obtained. Results: Four hundred seven oncology patients were included. Indications for chest CT imaging included baseline staging (31%), restaging after therapy (53%), routine surveillance (15%), or assessment of extrathoracic disease (1%). Clinically unsuspected PE were detected in 18 patients (4.4%). The prevalence of unsuspected PE was 6.4% among inpatients and 3.4% among outpatients. PE was more prevalent among patients with metastatic disease (7% versus 2%, p = 0.007) and in patients who had received recent chemotherapy (11% versus 3%, p = 0.008). In 7 (39%) of the 18 patients with clinically unsuspected PE, emboli were only identifiable on the CTPA study and not on the routine chest CT study. The diagnosis of PE led to immediate changes in patient management. Conclusion: Clinically unsuspected PE is present in up to 4.4% of oncology patients undergoing CT imaging for indications other than PE diagnosis. Modifying standard CT imaging protocols to include a CTPA examination optimizes their detection and leads to changes in patient management.

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.