High-pitched tin-filtered CT pulmonary angiography in radiation dose reduction for pulmonary embolism investigations in young females.

INTRODUCTION: Computed tomography pulmonary angiography (CTPA) is the gold standard test to investigate pulmonary embolism (PE). This technique carries significant radiation risk in young females because of radiosensitive breast and thyroid tissues. A high-pitched CT technique offers significant radiation dose reduction (RDR) and minimises breathing artefact. The addition of CT tube tin-filtration may offer further RDR. The aim of this retrospective study was to assess RDR and image quality (IQ) of high-pitch tin-filtered (HPTF)-CTPA against conventional-CTPA. METHODS: Retrospective review of consecutive adult females age < 50 years undergoing high pitch tin filtration (HPTF) and standard pitch no tin filtration (SPNF) during a 3-year period beginning in November 2017. CTs in both groups were compared for radiation dose, pulmonary arteries contrast density (Hounsfield units (HU)) and movement artefact. Findings of both groups were compared with the Student's T-test and Mann-Whitney U test, where p < 0.05 being considered significant. Diagnostic quality was also recorded. RESULTS: Ten female patients (mean age 33, 6/10 pregnant) in HPTF group and 10 female patients (mean age 36, 1/10 pregnant) in SPNF group were included. The HPTF group achieved 93% RDR (dose length product: 25.15 mGy.cm vs 337.10 mGy.cm, p < 0.01). There was significant contrast density difference between the two groups in the main, left or right pulmonary arteries (322.72 HU, 311.85 HU and 319.41 HU in HPTF group vs 418.60 HU, 405.10 HU and 415.96 HU in SPNF group respectively, p = 0.03, p = 0.03 and p = 0.04). 8/10 HPTF group and 10/10 in the control group were > 250 HU in all three vessels; the remaining 2 HPTF CTPA were > 210HU. All CT scans in both groups were of diagnostic quality and none exhibited movement artefact. CONCLUSION: This study was the first to demonstrate significant RDR with the HPTF technique whilst maintaining IQ in patients undergoing chest CTPA. This technique is particularly beneficial in young females and pregnant females with suspected PE.

Venous air embolism in CT coronary angiography.

INTRODUCTION: Venous air embolization (VAE) from IV lines is a risk with IV contrast administration. The incidence of VAE ranges from 7% to 23%. While life-threatening VAE is rare, there is the potential risk of serious cerebrovascular events from paradoxical systemic air embolization (SAE) in patients with congenital intracardiac shunts. CT coronary angiogram (CTCA) hypothetically carries a higher risk of VAE as it requires dual injections as compared to single bolus dose contrast used in CT chest (CTC). The aim of this study was to assess the risk of VAE using CTCA as compared to conventional CTC. The incidence of cardiac shunts and their association with paradoxical SAE were also investigated. METHODS: A retrospective study was conducted at a tertiary hospital. Adult patients undergoing CTCA and CTC over a 6-month period in 2017 were included. Images were reviewed on PACS for the presence of VAE. Electronic medical records were interrogated for evidence of neurological sequelae or requiring neurological imaging (CTB/MRIB) within 1 month of the initial imaging. RESULTS: 508 patients were included, 408 underwent CTCA and 100 underwent CTC. The VAE incidence in CTCA was 24% (94 patients) and 10% in the CTC (10 patients). This was statistically significant. Among the CTCA group, 36% (108 patients) had an intracardiac shunt. No statistically significant difference in VAE incidence was identified in CTCA patients with shunts vs without shunts. There was no incidence of SAE in both groups. CONCLUSION: VAE is more common with CTCA than conventional CTC. There were no cases of paradoxical SAE found.

An up-to-date review of cardiac pacemakers and implantable cardioverter defibrillators.

Cardiac pacemakers are one of the most frequently encountered cardiac devices seen on chest imaging. They may include single or dual chamber pacemakers, automated implantable cardioverter defibrillators (AICD), biventricular pacemakers used for cardiac resynchronisation therapy (CRT), wireless CRT, leadless pacemakers, and subcutaneous implantable cardioverter defibrillators (SICD). This review aims to provide an up-to-date review on current implantable pacemaker and defibrillator devices.

Gelfoam slurry tract occlusion after computed tomography-guided percutaneous lung biopsy: Does it prevent major pneumothorax?

INTRODUCTION: Computed tomography (CT)-guided lung biopsy is a frequently performed procedure in the diagnostic workup for suspicious lung nodules that can be complicated by pneumothorax. This retrospective study assessed the efficacy of biopsy tract occlusion with a gelatin sponge slurry for preventing post-biopsy pneumothorax. METHODS: Retrospective analysis was conducted on consecutive adult patients who underwent CT-guided lung biopsy over a 10-year period. Age, gender, existing chronic obstructive pulmonary disease (COPD), evidence of emphysema on CT, location of the lesion and the presence of pneumothorax on post-procedure CT and 4-h chest radiograph were recorded. RESULTS: Two hundred and ninety-six patients were included (126 patients in the non-gelfoam group and 170 in the gelfoam group). When gelfoam was used, risk of developing an immediate pneumothorax was lower (P = 0.032). Patients with emphysema were 2.4 times more likely to develop a delayed pneumothorax without gelfoam (P = 0.034). There was a significantly higher risk of both immediate and delayed pneumothorax in non-peripheral lesions without gelfoam (P = 0.001 and P = 0.002, respectively). The frequency of requiring a chest tube to treat a pneumothorax was 86% lower when gelfoam was used (P = 0.012). CONCLUSION: Gelfoam is effective in preventing immediate pneumothorax. In patients with emphysema, there was a significantly higher risk of delayed pneumothorax without gelfoam. Additionally, non-peripheral lesions were more likely to develop pneumothorax when gelfoam was not used. The use of gelfoam was especially important in preventing the development of major pneumothoraces that would require drainage with a chest tube.

An Uncommon Presentation of a Primary Bone Tumor: Anti-AMPA (Anti-α-Amino-3-Hydroxy-5-Methyl-4-Isoxazolepropionic acid) Receptor Limbic/Paraneoplastic Encephalitis as a Presenting Feature of Ewing Sarcoma.

Anti-AMPA (anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) receptor limbic encephalitis is a rare autoimmune syndrome. It can be associated with an underlying malignancy, such as lung, breast, or thymus. We are reporting a case of a 19-year-old patient who presented with a 2-week history of confusion and short-term memory loss. A magnetic resonance imaging of brain showed increased T2 hyperintensity within the hippocampi bilaterally. Cerebrospinal fluid analysis was positive for anti-AMPA receptor antibodies. A computed tomography revealed multiple pulmonary metastases as well as an expansile lucent and sclerotic lesion in the ilium, which was subsequently biopsied. Histopathology confirmed a diagnosis of Ewing sarcoma (ES). Fluorescence in situ hybridization testing of the specimen identified EWSR1 (22q12.2) signal rearrangements in 80% of cells scored. To date, this is the first case report describing anti-AMPA receptor limbic/paraneoplastic encephalitis as a presenting feature of ES. Although it is rare, the possibility of ES may be considered in young patients presenting with anti-AMPA receptor limbic encephalitis.

Efficacy of 'breath holding at ease' during CT pulmonary angiography in the improvement of contrast enhancement in pulmonary arteries.

INTRODUCTION: The aim of this study is to assess whether breath-hold at ease by patients during the CT pulmonary angiography (CTPA) will improve contrast enhancement in pulmonary arteries. METHODS: Retrospective review was conducted on 51 consecutive CTPA studies undertaken in the traditional method of patients taking deep inspiration and breath-hold immediately prior to scanning, and subsequently 75 consecutive CTPA studies with patients breathing-holding at ease immediately prior to and during the scanning. Attenuation values in pulmonary arteries of different anatomical levels in both groups were measured in Hounsfield unit (HU). Results were compared between the two groups. RESULTS: The mean attenuation value in pulmonary arteries including pulmonary trunk, main and proximal pulmonary arteries calculated in HU in the 'deep inspiration and breath-hold' group was 327 HU (95% confidence interval: 315 to 339 HU). The mean attenuation value in pulmonary arteries in the 'breath hold at ease' group was calculated to be 390 HU (95% confidence interval: 381 to 399 HU); that is, an overall 17.95% increase (P-value < 0.0001) in attenuation value in this group. CONCLUSIONS: By asking patients to breath-hold at ease instead of taking deep inspiration and breath hold prior to CTPA scan can effectively improve contrast enhancement in pulmonary arteries, therefore producing a higher-quality CT pulmonary angiography scan.

Extra-medullary haematopoiesis: a pictorial review of its typical and atypical locations.

Extra-medullary haematopoiesis (EMH) occurs in many haematological disorders and is secondary to insufficient bone marrow function or ineffective erythropoiesis. It usually presents as haematopoietic masses in several typical and atypical body locations. This pictorial review briefly discusses the common EMH locations encountered in clinical practice, including the liver, spleen, lymph nodes and paravertebral regions. Unusual presentation as focal hepatic and splenic masses is also discussed. Some atypical EMH locations are then presented together with their pathophysiology and relevant illustrations. These include EMH in the intra-spinal canal, pre-sacral region, nasopharynx and paranasal sinuses. Intra-spinal EMH can cause cord compression and present with neurological symptoms. In these cases, urgent treatment may be required. Haematopoietic masses in the other atypical locations can present with obstructive symptoms or may be diagnosed incidentally on imaging. EMH in unusual locations need to be monitored with follow-up imaging to ensure their stability. In some circumstances, tissue biopsy is appropriate to confirm the diagnosis and exclude other sinister pathology (e.g. malignancy). Treatment is only required where symptoms are present. Management options include blood transfusion, radiotherapy, hydroxyurea or surgical resection in selected cases.