Anomalous right upper lobe venous drainage

Lung resections are usually not associated with significant bleeding, but can be fatal, especially in cases of video-assisted thoracoscopic surgery (VATS). Anomalous vascular structures could be a major reason for unexpected bleeding in such surgeries. We present a case of an aberrant upper lobe pulmonary vein that was encountered posterior to the right upper lobe bronchus during a right upper lobectomy via thoracotomy. The anomalous pulmonary vein was identified preoperatively on a computed tomography (CT) scan and hence was looked for before dividing the bronchus. Many centres are adopting the VATS approach for performing lung resections. If an anomalous vein is present posterior to the bronchus, it might be in a blind spot and could be damaged inadvertently, leading to profuse and potentially fatal bleeding. We conclude that the identification of anomalous vascular structures prior to surgery with the help of CT helps in avoiding adverse outcomes.

Increasing the accuracy of 18F-FDG PET/CT interpretation of "mildly positive" mediastinal nodes in the staging of non-small cell lung cancer

INTRODUCTION

The aim of this study was to identify radiological factors that may reduce false-positive results and increase diagnostic accuracy when staging the mediastinum of patients with non-small cell lung carcinoma (NSCLC).

METHODS

This was a retrospective, interdisciplinary, per-node analysis study. We included patients with NSCLC and mediastinal nodes with an SUV max in the range of 2.5-4.0 on PET-CT. We hypothesized that the greatest number of false positive cases would occur in this cohort of patients.

RESULTS

A total of 92 mediastinal lymph nodes were analyzed in 44 patients. Mediastinal disease (N2/N3) was histologically confirmed in 15 of 44 patients and in 34 of 92 lymph nodes; positive predictive value of 37% and false positive rate of 63%. Lymph node SUV max, tumor size, ratio of node SUV max to tumor SUV max (SUVn/SUVp), and ratio of node SUV max to node size (SUV n/SADn) were significantly higher in true positive cases. Using a threshold of 0.3 for SUV node/tumor and 3 for SUV node/size yielded sensitivities of 91% and 71% and specificities of 71% and 69% respectively for the detection of mediastinal disease. Using both ratios in combination resulted in a sensitivity of 65% and a specificity of 88%. Concurrent benign lung disease was observed significantly more frequently in false-positive cases.

CONCLUSION

SUVn/SUVpt and SUVn/SADn may be complimentary to conventional visual interpretation and SUV max measurement in the assessment of mediastinal disease in patients with NSCLC.

Plain abdominal radiographs in patients with Crohn's disease: radiological findings and diagnostic value

AIM

To determine the diagnostic yield and clinical value of plain film of the abdomen (PFA) in Crohn's disease (CD) patients and to determine whether performance of PFA yields definitive diagnostic information or whether additional imaging examinations are required.

MATERIALS AND METHODS

One hundred and seventy-seven CD patients underwent 643 PFAs during the period September 1992 to August 2008. Two radiologists blinded to the clinical details independently evaluated individual PFAs and/or their reports for abnormal findings using the following criteria: normal, small bowel (SB) findings; colonic findings, acute CD complications, extra-colonic findings; global assessment/impression. The results of additional imaging studies performed within 5 days of PFA were recorded and findings were analysed.

RESULTS

A mean of 3.6 (range 1-22) PFAs was performed per patient during the study period. Almost 70% of films were normal (n = 449). SB abnormalities were detected in 21.8% (n = 140) PFAs; most commonly dilated loops (18.8%, n = 121) and mucosal oedema (5%, n = 32). Colonic abnormalities were present in 11.4% (n = 73); most commonly mucosal oedema (7.5%, n = 48) and dilated loops (5%, n = 32). Four cases of pneumoperitoneum were detected. There was no case of toxic megacolon. There was one case in which intra-abdominal abscess/collection was suspected and two cases of obstruction/ileus. Extracolonic findings (renal calculi, sacro-iliitis, etc.) were identified in 7.5% (n = 48). PFAs were followed by additional abdominal imaging within 5 days of PFA in 273/643 (42.5%) of cases.

CONCLUSION

Despite the high rates of utilization of PFA in CD patients, there is a low incidence of abnormal findings (32.5%). Many of the findings are non-specific and clinically irrelevant and PFA is frequently followed by additional abdominal imaging examinations.

Imaging features of bowel toxicities in the setting of molecular targeted therapies in cancer patients

Molecular targeted therapies are becoming ubiquitous in cancer treatment. These drugs may cause gastrointestinal toxicities including perforation, pneumatosis, enteritis, colitis and fistula formation. Knowledge of these complications and their management enables early radiological identification and appropriate intervention, reducing patient morbidity and mortality.

Image quality associated with the use of an MR-compatible incubator in neonatal neuroimaging

OBJECTIVES

MRI in the neonate poses significant challenges associated with patient transport and monitoring, and the potential for diminished image quality owing to patient motion. The objective of this study was to evaluate the usefulness of a dedicated MR-compatible incubator with integrated radiofrequency coils in improving image quality of MRI studies of the brain acquired in term and preterm neonates using standard MRI equipment.

METHODS

Subjective and objective analyses of image quality of neonatal brain MR examinations were performed before and after the introduction of an MR-compatible incubator. For all studies, the signal-to-noise ratio (SNR) was calculated, image quality was graded (1-3) and each was assessed for image artefact (e.g. motion). Student's t-test and the Mann-Whitney U-test were used to compare mean SNR values.

RESULTS

39 patients were included [mean gestational age 39 weeks (range 30-42 weeks); mean postnatal age 13 days (range 1-56 days); mean weight 3.5 kg (range 1.4-4.5 kg)]. Following the introduction of the MR-compatible incubator, diagnostic quality scans increased from 50 to 89% and motion artefact decreased from 73 to 44% of studies. SNR did not increase initially, but, when using MR sequences and parameters specifically tailored for neonatal brain imaging, SNR increased from 70 to 213 (p=0.001).

CONCLUSION

Use of an MR-compatible incubator in neonatal neuroimaging provides a safe environment for MRI of the neonate and also facilitates patient monitoring and transport. When specifically tailored MR protocols are used, this results in improved image quality.

Crohn's disease: factors associated with exposure to high levels of diagnostic radiation

AIMS

Exposure to diagnostic radiation may be associated with increased risk of malignancy. The aims of this study were to (1) examine patterns of use of imaging in Crohn's disease; (2) quantify the cumulative effective dose (CED) of diagnostic radiation received by patients; and (3) identify patients at greatest risk of exposure to high levels of diagnostic radiation.

METHODS

409 patients with Crohn's disease were identified at a tertiary centre. CED was calculated retrospectively from imaging performed between July 1992 and June 2007. High exposure was defined as CED>75 mSv, an exposure level which has been reported to increase cancer mortality by 7.3%. Complete data were available for 399 patients. 45 were excluded (20 attended outside the study period, 25 were primarily managed at other centres).

RESULTS

Use of computed tomography increased significantly and accounted for 77.2% of diagnostic radiation. Mean CED was 36.1 mSv and exceeded 75 mSv in 15.5% of patients. Factors associated with high cumulative exposure were: age <17 years at diagnosis (hazard ratio 2.1, confidence interval (CI) 1.1 to 4.1), upper gastrointestinal tract disease (odds ratio (OR) 2.4, CI 1.2 to 4.9), penetrating disease (OR 2.0, CI 1.0 to 3.9) and requirement for intravenous steroids (OR 3.7, CI 2.0 to 6.6); infliximab (OR 2.3, CI 1.2 to 4.4); or multiple (>1) surgeries (OR 2.7, CI 1.4 to 5.4).

CONCLUSIONS

Identifiable subsets of patients with Crohn's disease are at risk of exposure to significant amounts of diagnostic radiation. Given the background risk of neoplasia and exposure to potentially synergistic agents such as purine analogues and other immune modulators, specialist centres should develop low-radiation imaging protocols.

Thromboprophylaxis using a low molecular weight heparin delays fracture repair

Low molecular weight heparins are significantly superior to unfractionated heparin or warfarin in the prevention of thromboembolic episodes associated with orthopaedic surgery. Therapeutic doses of heparin and warfarin have been shown to delay bone repair in a rabbit model. The current study investigated the effect of prophylactic administration of a low molecular weight heparin, enoxaparin, on the healing of a closed rabbit rib fracture. Fracture healing was assessed using histomorphometric, histologic, and immunohistochemical methods at 3, 7, and 14 days, and biomechanical testing with torsional loading was assessed after 21 days. Bone repair was significantly attenuated at all times in animals receiving subcutaneous enoxaparin compared with that of the control animals. Numerous putative mechanisms for this phenomenon are discussed, and additional studies are proposed to elucidate the effects of this pharmacologically diverse group of compounds on all aspects of bone physiology and repair.