CT pulmonary arteriogram diagnosis of macroscopic fat embolism to the lung.

Pulmonary fat embolism (PFE) is a recognised complication of long bone fractures. The majority of cases represent microscopic embolism and are not detectable at CT pulmonary arteriography (CTPA). CT can be used to detect macroscopic fat based on Hounsfield attenuation. This case describes a case of macroscopic fat embolism to the pulmonary arteries which was confidently diagnosed at CTPA. Distinction from thromboembolism is important as treatment is supportive and may avoid risks of anticoagulation.

The role of radiology in addressing the challenge of lung cancer after lung transplantation.

The importance of lung cancer as a complication of lung transplantation is increasingly recognised. It may become an important survival-limiting factor in lung transplant patients as management of other complications continues to improve and utilisation of extended criteria donors grows. Radiology can play a key role in tackling this issue at multiple stages in the transplantation pathway and follow-up process. Routine chest CT as part of pre-transplant recipient assessment (and donor assessment if available) can identify suspicious lung lesions with high sensitivity and detect chronic structural lung diseases such as pulmonary fibrosis associated with an increased risk of malignancy post-transplant. Pre-transplant CT also provides a comparison for later CT studies in the assessment of nodules or masses. The potential role of regular chest CT for lung cancer screening after transplantation is less certain due to limited available evidence on its efficacy. Radiologists should be cognisant of how the causes of pulmonary nodules in lung transplant patients may differ from the general population, vary with time since transplantation and require specific recommendations for further investigation/follow-up as general guidelines are not applicable. As part of the multidisciplinary team, radiology is involved in an aggressive diagnostic and therapeutic management approach for nodular lung lesions after transplant both through follow-up imaging and image-guided tissue sampling. This review provides a comprehensive overview of available clinical data and evidence on lung cancer in lung transplant recipients, and in particular an assessment of the current and potential roles of pre- and post-transplant imaging. KEY POINTS: • Lung cancer after lung transplantation may become an increasingly important survival-limiting factor as mortality from other complications declines. • There are a number of important roles for radiology in tackling the issue which include pre-transplant CT and supporting an aggressive multidisciplinary management strategy where lung nodules are detected in transplant patients. • The introduction of routine surveillance chest CT after transplant in addition to standard clinical follow-up as a means of lung cancer screening should be considered.

MRI safety management in patients with cardiac implantable electronic devices: Utilizing failure mode and effects analysis for risk optimization.

INTRODUCTION: Cardiac implantable electronic devices (CIEDs) are increasing in prevalence. Exposing patients with CIEDs to magnetic resonance imaging (MRI) can lead to adverse outcomes. This has led certain radiology departments to not accept MRI referrals related to patients with CIEDs. Patients with MR-conditional CIEDs can be safely scanned under specific conditions. Our institution has accepted such referrals since 2014. The aim of this study was to systematically identify and reduce risk in our CIED-MRI protocol using failure mode and effects analysis (FMEA). METHODS: A multidisciplinary FMEA team was assembled and included senior stakeholders from the CIED-MRI protocol. A process map was constructed followed by risk analysis and scoring. Targeted interventions were formulated and implemented; high-risk failure modes were prioritized. A new process map and protocol were drafted and repeat risk analysis was performed. Monitoring and re-evaluation of the CIED-MRI pathway were instigated at departmental quality assurance (QA) meetings. RESULTS: Interventions included direct CIED characterization using wireless technology pre-MRI, CIED programming and reprogramming in the MRI suite before and immediately after MRI reducing device downtime and continuous patient monitoring during MRI by a cardiac physiologist. The cumulative risk priority number (RPN) decreased from 1190 pre-FMEA to 492 post-FMEA. DISCUSSION: Despite the risk of exposing CIEDs to the MR environment, patients with MR-conditional CIEDs can be safely scanned with an appropriate multidisciplinary support. We found FMEA an indispensable tool in identifying and minimizing risk with no adverse events recorded since FMEA recommendations were implemented.

Scintigraphic assessment of arterial embolism at mixed thrombin and technetium 99m injection therapy for femoral pseudoaneurysms.

BACKGROUND: Clinically evident arterial thrombosis is rare following thrombin injection therapy for femoral pseudoaneurysm. However, it is unclear to what extent injected thrombin may pass to the ipsilateral lower limb arteries. AIMS: To assess if technetium 99m injected at the time of thrombin injection for femoral artery pseudoaneurysm therapy passes into the adjacent lower limb arteries. METHODS: This was a prospective trial with institutional review board approval. Four consecutive patients with common femoral pseudoaneurysms and failed manual compression were enrolled. Under real-time colour flow doppler ultrasound, a mixture of 1000 IU thrombin and approximately 200 MBq technetium 99m was injected in 0.1-mL doses into the pseudoaneurysm until thrombosis occurred. Gamma camera imaging of the syringe before injection, the injected groin after thrombosis and the syringe after injection were performed. Analysis of the gamma camera information was performed to determine the amount of technetium 99m deposited in the arterial tree. RESULTS: All the procedures were technically successful. A mean of 33% (range 3-50%; SD 21) of the administered technetium 99m dose was deposited in the arterial circulation during pseudoaneurysm therapy. No clinically evident arterial thrombosis was identified. CONCLUSION: Technetium 99m is routinely deposited in the arterial circulation following injection of a mixture of thrombin and technetium for therapy of common femoral artery pseudoaneurysms. This suggests that arterial passage of thrombin is more common than clinically evident.

Provision of MR imaging for patients with cardiac implantable electronic devices (CIEDs): a single-center experience and national survey.

BACKGROUND: Patients with cardiac implantable electronic devices (CIEDs) were traditionally denied access to MR imaging due to safety concerns. AIMS: The aim of this study was to review a single-center experience of MR imaging at 1.5T of patients with CIEDs and survey national availability of this service. METHODS: Three hundred thirty-four patients with CIEDs were included in the review. Two hundred nine patients did not progress to MRI due to non MR-conditional CIEDs, retained pacing leads, recent implant insertion, and other patient factors. A record was made of CIED type, number of body parts imaged, numbers of repeat studies and complications. All devices were scanned with cardiology involvement. RESULTS: One hundred twenty-five patients, 90 males, 35 females, aged 20-91 years progressed to MR imaging. Eighty-six patients had pacemakers, 15 had implantable cardioverter devices (ICDs), and 24 had implantable loop recorders (ILRs). Twenty-one patients had more than one body part scanned. Regions scanned included spine n = 82, joints n = 42, head n = 40, heart n = 8, and abdomen/pelvis n = 13. Twenty-six patients had multiple separate MR studies (range 2-6). Three complications included diaphragmatic stimulation when the device was switched to MR-conditional mode resulting in scan abandonment, device failure post-MRI requiring manufacturer reprogramming, and patient dizziness post reprogramming requiring cardiology review. One cardiac study was non-diagnostic due to artifact from a low left-sided ICD. Imaging of patients with pacemakers is available in 14 of 42 (38%) hospitals with MR units nationally. CONCLUSION: MR-conditional CIEDs can be safely scanned with diagnostic quality at 1.5T using a protocol involving radiology and cardiology.

Frequency of nonthromboembolic imaging abnormalities in pregnant women referred for computed tomography pulmonary arteriography.

PURPOSE: The study sought to determine the frequency of nonthromboembolic imaging abnormalities in pregnant women referred for computed tomography pulmonary arteriography (CTPA). MATERIALS AND METHODS: CTPA studies on 100 consecutive pregnant women performed over a 5-year period were reviewed independently by 2 radiologists, with conflicts resolved by consensus. Age range was 18-43 years (mean 28 years). The presence or absence of pulmonary embolism and of nonthromboembolic imaging abnormalities was recorded. These were graded as A if the abnormalities were thought to provide potential alternative explanations for acute symptoms, B if findings were incidental that required clinical or radiologic follow-up, and C if the findings did not require further action. RESULTS: Pulmonary embolism was seen in 5 women. In 2 of these additional findings of consolidation and infarction were seen. Ninety-five women did not have pulmonary embolism. Eleven women (12%) had grade A abnormalities; 6 cases of consolidation, 2 cases of lobar collapse, and 3 cases of heart failure with pleural effusions. One woman had a grade B abnormality due to the presence of pulmonary nodules. Ten women had incidental grade C abnormalities. CONCLUSION: Pulmonary embolism occurs in 5% of pregnant women referred for CTPA. In pregnant women without embolism on CTPA, potential alternative causes for patient symptoms are seen on CT in 12% of cases.

Percutaneous transthoracic computed tomography-guided AICD insertion in a patient with extracardiac Fontan conduit.

Percutaneous pulmonary venous atrial puncture was performed under computed tomography guidance to successfully place an automated implantable cardiac defibrillator into a 26-year-old patient with extracardiac Fontan conduit who had presented with two out-of-hospital cardiac arrests. The procedure avoided the need for lead placement at thoracotomy.

The role of whole-body imaging in the diagnosis, staging, and follow-up of multiple myeloma.

Multiple myeloma is one of the most common hematological malignancies and accounts for significant morbidity and mortality. In the past, detection of myelomatous deposits by radiography was the main method of radiological assessment in this disease. However, in recent years the introduction of whole-body imaging techniques, specifically low-dose whole-body computed tomography, whole-body magnetic resonance imaging, and positron emission tomography, has facilitated a more comprehensive assessment of this heterogeneous and often diffuse disease. Each of these whole-body imaging techniques has specific applications and limitations in the assessment of multiple myeloma that the interpreting radiologist and referring clinician need to be aware of. As these techniques gain further acceptance in the radiology and hematology communities, their use in the assessment of multiple myeloma is likely to increase further.

Cardiac MRI in arrhythmogenic right ventricular cardiomyopathy.

OBJECTIVE: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a cause of sudden cardiac death in otherwise healthy young adults. This article outlines the spectrum of MRI findings in ARVC using a combination of static and cine images. CONCLUSION: The detection of right ventricular enlargement, fatty infiltration, fibrosis, and wall motion abnormalities at MRI is useful in the diagnosis of ARVC.

Steady-state free-precession (SSFP) cine MRI in distinguishing normal and bicuspid aortic valves.

PURPOSE: To assess the diagnostic sensitivity and specificity of double-oblique true fast imaging with steady-state precession (SSFP) cine MRI in distinguishing normal and bicuspid aortic valves. MATERIALS AND METHODS: Echocardiograms on patients referred for MRI of the heart and thoracic aorta over a four-year period were reviewed retrospectively. A total of 17 patients with bicuspid aortic valve were identified and compared to 21 randomly chosen control patients. All patients had double-oblique SSFP (True FISP) cine MRI of the aortic valve independently assessed by two radiologists in a blinded fashion, and graded as bicuspid or normal. Image quality was graded as 1, 2, or 3. Discordance was resolved by consensus. RESULTS: A total of 38 cases were reviewed (27 men, 11 women; age range = 15-67 years, mean = 25.33 years). Interobserver agreement was 0.97 (36/38 cases). One case of normal tricuspid valve was reported as bicuspid by both readers (false-positive). All cases in which disparity arose were rated suboptimal by both readers (grade 2 or 3). Consensus review yielded sensitivity = 100%, specificity = 95.2%, positive predictive value = 94.4%, and negative predictive value = 100%; overall diagnostic accuracy was 97.36%. Interobserver agreement was 0.97. CONCLUSION: Double-oblique True FISP cine MR imaging of the aortic valve is 100% sensitive and 95% specific in distinguishing normal and bicuspid aortic valves.

Large-bore gastrostomy feeding tube insertion by a pull technique using a snare.

We describe a series of three patients who had fluoroscopic-guided placement of a large-bore gastrostomy tube using a pull technique and a large snare placed via a nasogastric or orogastric tube.

MR venography with true fast imaging with steady-state precession for suspected lower-limb deep vein thrombosis.

PURPOSE: To compare true fast imaging with steady-state precession (FISP) magnetic resonance (MR) venography for suspected deep vein thrombosis (DVT) with contrast agent-enhanced venography. MATERIALS AND METHODS: This was a prospective study of randomly selected patients with a clinical suspicion of DVT of the lower limb. Standard contrast venography was performed and compared with MR venography from the inferior vena cava to the feet in 24 patients with use of true FISP sequences (repetition time, 3.74 msec; echo time, 1.8 msec). Two radiologists independently read the MR venography and contrast venography studies. Segment visibility, secondary signs of DVT, and additional diagnoses were noted. RESULTS: MR venography demonstrated all venous segments in the pelvis and thigh. When results were analyzed on a per-patient basis, there was good agreement between contrast venography and MR venography (kappa = 0.64; 95% CI, 0.33-0.94; P = .0001). When the venous system was analyzed on a segmental basis, there was very good agreement between contrast venography and MR venography (kappa = 0.81; 95% CI, 0.68-0.94; P = .0001). The sensitivity and specificity for DVT detection were 100% for the iliac and popliteal segments and 100% and 98%, 68% and 94%, and 87% and 98%, respectively, for the femoral, below-knee, and all veins. Eleven of 14 patients without DVT had an alternative diagnosis suggested by MR venography. CONCLUSIONS: MR venography with axial true FISP allows noninvasive rapid diagnosis of acute DVT in the iliac, femoral, popliteal, and calf muscle veins. MR venography is much less reliable in the tibial or peroneal veins. It may demonstrate a nonvenous cause of a patient's symptoms.