Stephen J. Skehan

Pulmonary Embolism in Pregnancy: Comparison of Pulmonary CT Angiography and Lung Scintigraphy

OBJECTIVE The purpose of this study was to retrospectively compare the diagnostic adequacy of lung scintigraphy with that of pulmonary CT angiography (CTA) in the care of pregnant patients with suspected pulmonary embolism. MATERIALS AND METHODS Patient characteristics, radiology report content, additional imaging performed, final diagnosis, and diagnostic adequacy were recorded for pregnant patients consecutively referred for lung scintigraphy or pulmonary CTA according to physician preference. Measurements of pulmonary arterial enhancement were performed on all pulmonary CTA images of pregnant patients. Lung scintigraphy and pulmonary CTA studies deemed inadequate for diagnosis at the time of image acquisition were further assessed, and the cause of diagnostic inadequacy was determined. The relative contribution of the inferior vena cava to the right side of the heart was measured on nondiagnostic CTA images and compared with that on CTA images of age-matched nonpregnant women, who were the controls. RESULTS Twenty-eight pulmonary CTA examinations were performed on 25 pregnant patients, and 25 lung scintigraphic studies were performed on 25 pregnant patients. Lung scintigraphy was more frequently adequate for diagnosis than was pulmonary CTA (4% vs 35.7%) (p = 0.0058). Pulmonary CTA had a higher diagnostic inadequacy rate among pregnant than nonpregnant women (35.7% vs 2.1%) (p < 0.001). Transient interruption of contrast material by unopacified blood from the inferior vena cava was identified in eight of 10 nondiagnostic pulmonary CTA studies. CONCLUSION We found that lung scintigraphy was more reliable than pulmonary CTA in pregnant patients. Transient interruption of contrast material by unopacified blood from the inferior vena cava is a common finding at pulmonary CTA of pregnant patients.

Hepatocellular Carcinoma: Illustrated Guide to Systematic Radiologic Diagnosis and Staging According to Guidelines of the American Association for the Study of Liver Diseases

Hepatocellular carcinoma is a malignancy that predominantly occurs in the setting of cirrhosis. Its incidence is rising worldwide. Hepatocellular carcinoma differs from most malignancies because it is commonly diagnosed on the basis of imaging features alone, without histologic confirmation. The guidelines from the American Association for the Study of Liver Diseases (AASLD) are a leading statement for the diagnosis and staging of hepatocellular carcinoma, and they have recently been updated, incorporating several important changes. AASLD advocates the use of the Barcelona Clinic Liver Cancer (BCLC) staging system, which combines validated imaging and clinical predictors of survival to determine stage and which links staging with treatment options. Each stage of the BCLC system is outlined clearly, with emphasis on case examples. Focal liver lesions identified at ultrasonographic surveillance in patients with cirrhosis require further investigation. Lesions larger than 1 cm should be assessed with multiphasic computed tomography or magnetic resonance imaging. Use of proper equipment and protocols is essential. Lesions larger than 1 cm can be diagnosed as hepatocellular carcinoma from a single study if the characteristic dynamic perfusion pattern of arterial hyperenhancement and venous or delayed phase washout is demonstrated. If the imaging characteristics of hepatocellular carcinoma are not met, the alternate modality should be performed. Biopsy should be used if neither modality is diagnostic of hepatocellular carcinoma. Once the diagnosis has been made, the cancer should be assigned a BCLC stage, which will help determine suitable treatment options. Radiologists require a systematic approach to diagnose and stage hepatocellular carcinoma with appropriate accuracy and precision.

Positron emission tomography in the staging and management of breast cancer

Breast cancer is the commonest cause of cancer death in women in the Western world, and imaging is essential in its diagnosis and staging. Metabolic imaging is a novel approach to improving the detection of cancers, as malignant transformation of cells is often associated with increased metabolic activity. This review assesses the possible role of positron emission tomography (PET) as a single non‐invasive imaging modality to replace or complement current imaging and surgical practices in the diagnosis and staging of breast cancer.

Pulmonary CT Angiography Protocol Adapted to the Hemodynamic Effects of Pregnancy

OBJECTIVE The purpose of this study was to compare the image quality of a standard pulmonary CT angiography (CTA) protocol with a pulmonary CTA protocol optimized for use in pregnant patients with suspected pulmonary embolism (PE). MATERIALS AND METHODS Forty-five consecutive pregnant patients with suspected PE were retrospectively included in the study: 25 patients (group A) underwent standard-protocol pulmonary CTA and 20 patients (group B) were imaged using a protocol modified for pregnancy. The modified protocol used a shallow inspiration breath-hold and a high concentration, high rate of injection, and high volume of contrast material. Objective image quality and subjective image quality were evaluated by measuring pulmonary arterial enhancement, determining whether there was transient interruption of the contrast bolus by unopacified blood from the inferior vena cava (IVC), and assessing diagnostic adequacy. RESULTS Objective and subjective image quality were significantly better for group B-that is, for the group who underwent the CTA protocol optimized for pregnancy. Mean pulmonary arterial enhancement and the percentage of studies characterized as adequate for diagnosis were higher in group B than in group A: 321 ± 148 HU (SD) versus 178 ± 67 HU (p = 0.0001) and 90% versus 64% (p = 0.05), respectively. Transient interruption of contrast material by unopacified blood from the IVC was observed more frequently in group A (39%) than in group B (10%) (p = 0.05). CONCLUSION A pulmonary CTA protocol optimized for pregnancy significantly improved image quality by increasing pulmonary arterial opacification, improving diagnostic adequacy, and decreasing transient interruption of the contrast bolus by unopacified blood from the IVC.

Whole body imaging in the abdominal cancer patient: pitfalls of PET-CT

Proper interpretation of PET-CT images requires knowledge of the normal physiological distribution of the tracer, frequently encountered physiological variants, and benign pathological causes of FDG uptake that can be confused with a malignant neoplasm. In addition, not all malignant processes are associated with avid tracer uptake. A basic knowledge of the technique of image acquisition is also required to avoid pitfalls such as misregistration of anatomical and scintigraphic data. This article reviews these potential pitfalls as they apply to the abdomen and pelvis of patients with cancer.

Evaluation of a 3-hour indium-111 leukocyte image as a surrogate for a technetium-99m nanocolloid marrow scan in the diagnosis of orthopedic infection

Objectives: This is a retrospective study to evaluate a 3-hour In-111-labeled leukocyte image as a surrogate for a Tc-99m nanocolloid marrow scan in the investigation of suspected orthopedic infection using In-111 leukocyte scintigraphy. Methods: Images from 51 patients who had received contemporaneous In-111-labeled leukocyte scintigraphy and Tc-99m nanocolloid marrow scintigraphy were reviewed. Initially, the 3-hour and 22-hour In-111-labeled leukocyte images were compared. Sites of abnormal uptake on the 22-hour image were correlated with the 3-hour image and were graded according to the level of concordance or discordance. One week later, the Tc-99m nanocolloid images and 22-hour In-111-labeled leukocyte images of the same patients were compared and graded for concordance or discordance. When discrepancies in grading arose between the observers, a consensus opinion was achieved after additional review of the images a week later. Results: On inspection of the 22-hour In-111 leukocyte images, 93 sites of focal, potentially abnormal leukocyte accumulation were identified. When the grading system was reduced to simply “concordant” or “discordant,” there was good agreement between the observers in the majority of cases, with &kgr; statistics 0.77 for Tc-99m nanocolloid versus 22-hour In-111-labeled leukocyte images and 0.78 for 3-hour versus 22-hour In-111-labeled leukocyte images. Using the comparison of the Tc-99m nanocolloid marrow scan and the 22-hour In-111-labeled leukocyte images to identify concordance or discordance as the “gold standard” for scintigraphic evaluation of suspected orthopedic infection, comparison of the 3-hour In-111-labeled leukocyte images with the 3-hour In-111-labeled leukocyte images gave a sensitivity of 77%, a specificity of 77%, and an accuracy of 77%. Conclusions: A 3-hour image is helpful using In-111-labeled leukocyte scintigraphy.

Initial impact of a systematic multidisciplinary approach on the management of patients with gastroenteropancreatic neuroendocrine tumor

According to the international guidelines, a multidisciplinary approach is currently advised for the optimal care of patients with a gastroenteropancreatic neuroendocrine tumor (GEP NET). In our institution (tertiary care center), a systematic multidisciplinary approach was established in May 2007. In this study, we have aimed to assess the initial impact of establishing a systematic multidisciplinary approach to the management of GEP NET patients. We have collected and compared the biochemical, imaging, and pathological data and the therapeutic strategies in GEP NET patients diagnosed, treated, or followed-up from January 1993 to April 2007 versus GEP NET patients attending our institution after the multidisciplinary approach starting, from May 2007 to October 2008. Data of 91 patients before and 42 patients after the establishment of the multidisciplinary approach (total: 133 consecutive GEP NET patients) have been finally collected and analyzed. Before the establishment of the multidisciplinary approach, a lack of consistency in the biochemical, imaging, and pathological findings before treatment initiation as well as during follow-up of GEP NET patients was identified. These inconsistencies have been reduced by the systematic multidisciplinary approach. In addition, the therapeutic management of GEP NET patients has been altered by the multidisciplinary approach and became more consistent with recommended guidelines. We think that a systematic multidisciplinary approach significantly impacts on GEP NET patient care and should be established in all centers dealing with these tumors.

The Value of Isosulfan Blue Dye in Addition to Isotope Scanning in the Identification of the Sentinel Lymph Node in Breast Cancer Patients With a Positive Lymphoscintigraphy: A Randomized Controlled Trial (ISRCTN98849733).

BACKGROUND Sentinel lymph node biopsy (SLNB) has become the gold standard for axillary staging. Debate remains as to the optimal method of SLN detection. OBJECTIVES Determine whether patients undergoing an SLNB required the addition of isosulfan blue dye to radioisotope when an SLN was identified on a preoperative lymphoscintigram. METHODS A prospective randomized controlled trial comparing the combination of radioisotope and blue dye versus radioisotope alone was performed between March 2010 and September 2012. The trial protocol was registered with Current Controlled Trials. Women with clinically and radiologically node-negative breast cancer with a positive preoperative lymphoscintigram were eligible for inclusion. RESULTS A total of 667 patients were included in the analysis with 342 patients receiving the combination (blue dye and radioisotope) and 325 patients receiving radioisotope alone. The groups were evenly matched both demographically and pathologically. The mean age was 48 years (48.3 vs 47.7 years; P = 0.47), the mean tumour size was 24.2 mm (24.3 mm vs 24.1 mm; P = 0.7) and there was no statistically significant difference in the grade of the tumors between the 2 groups (P = 0.58). There was no difference in the identification rate, nor was that in the number of nodes retrieved between the 2 groups (P = 0.30). There was no difference in the number of positive lymph nodes that were identified between the 2 groups (23.8% vs 22.1%; P = 0.64). CONCLUSIONS This study failed to demonstrate an advantage with the addition of isosulfan blue dye to radioisotope in the identification of the SLN in the presence of a positive preoperative lymphoscintigram.

Staging of gastroenteropancreatic neuroendocrine tumors: how we do it based on an evidence-based approach

In contrast to other common types of malignant tumors, the vast majority of gastroenteropancreatic neuroendocrine tumors are well differentiated and slowly growing with only a minority showing aggressive behavior. It is important to accurately stage patients radiologically so the correct treatment can be implemented and to improve prognosis. In this article, we critically appraise the current literature in an effort to establish the current role of radiologic imaging in the staging of neuroendocrine tumors. We also discuss our protocol for staging neuroendocrine tumors.

Role of bone scan in addition to CT in patients with breast cancer selected for systemic staging.

The majority of women with breast cancer present with localized disease. The optimal strategy for identifying patients with metastatic disease at diagnosis remains unclear. The aim of this study was to evaluate the additional diagnostic yield from isotope bone scanning when added to CT staging of the thorax, abdomen and pelvis (CT‐TAP) in patients with newly diagnosed breast cancer.