China
Africa
Explore chapters and articles related to this topic
The Mediastinum (including pre-and para-spinal lines, neural tumours, and pneumomediastinum).
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
Intrathoracic goitres descend from the isthmus of the thyroid (Illus. THYROID LINGUAL, Thyroid Pts. 40 & 52), in front of the great veins. They may lie anywhere between the posterior part of the tongue and the aortic arch or sometimes even lower (Illus. THYROID, Pt. 39a-b). About a third of mediastinal goitre become displaced behind the trachea and great vessels, and may even extend around and behind the oesophagus. Displacement usually occurs on the right, and these goitres are probably derived from the posterior and lateral aspects of the thyroid and may mimic an intrapulmonary mass (Illus. THYROID, Pts. 31-37). When not fixed (usually because of their size) goitres tend to move upwards on swallowing. A band between the goitre and the normal thyroid may sometimes be demonstrated by CT or more commonly an isotope scan. Calcification within a goitre is very common and is usually nodular or ring-like in type. It appears to result from previous local haemorrhages and is best seen on tomograms. On CT sections a goitre is often a little denser than muscle, it also shows marked persisting contrast enhancement. Hypervascularity may be shown on angiograms. Most intrathoracic goitres are only minimally hormonally active, and an isotope scan using I131, I123 or Tc99m pertechnctatc (which behaves as a halogen) tends to reflect this, and in most cases only a little of the isotope is taken up, but it is usually enough for diagnosis.
Ultrasound Physics
Published in Debbie Peet, Emma Chung, Practical Medical Physics, 2021
Ultrasound contrast agents: Vascular ultrasound contrast agents take the form of tiny “microbubbles” that are introduced to the blood stream to enhance the ultrasound signal from blood flow. Microbubbles can be generated through agitation of saline and are commercially available as vials of encapsulated microbubbles. Each vial contains millions of 1–10 µm diameter bubbles containing a biocompatible inert gas, encapsulated in a lipid shell. These improve the visibility of vessels and can potentially be targeted to adhere to thrombus or tumours. Contrast-enhanced ultrasound (CEUS) imaging is often used as an adjunct to conventional B-mode imaging to distinguish between benign and malignant tumours through identifying hypervascularity associated with tumour growth.
Endocrine system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Ultrasound: normal adrenal glands may be visible on ultrasound using the liver, spleen, and/or kidneys as an acoustic window, although visualisation is often impaired by patient body habitus or interposition of lung in the costophrenic sulci. Small tumours may be detectable but are often homogeneous and hypoechoic so that characterisation is not possible [4]. Larger tumours (over 3 cm) are more readily detected, and are often heterogeneous due to haemorrhage or necrosis. Hypervascularity can be assessed by ultrasound and may indicate malignancy or phaeochromocytoma (PCC).
Preoperative embolization of suprasellar hemangioblastoma supplied by artery of foramen rotundum: a case report and review of the literature
Published in British Journal of Neurosurgery, 2023
Sungjun Moon, Hui Joong Lee, Subum Lee
Preoperative embolization may provide a useful option for reducing tumor hypervascularity but the procedure is not straightforward when the calibers of feeding arteries are small as was the case here on the right.3 On the left, angiography showed the AFR main feeder with a distinctive corkscrew shape. The AFR branches from the distal IMA, passes through the foramen rotundum, and connects to anterolateral branches of the inferolateral trunk, itself a branch of the internal carotid. So the AFR forms a potential anastomosis between the ECA and ICA.4 In addition, the presence of the artery of superior orbital fissure is also important. This artery arises at the distal IMA, either singly or from a common trunk with AFR, and then runs upward to reach the superior orbital fissure and anastomose with the anteromedial branch of the inferolateral trunk or the ophthalmic artery.5 Reflux of embolic material, therefore, carries risks of blindness or parenchymal embolic infarction, and we recommend preoperative AFR embolization is performed with proper mixtures of Histoacryl and Lipiodol under continuous fluoroscopy to avoid complications.
Emerging immune checkpoint inhibitors for the treatment of hepatocellular carcinoma
Published in Expert Opinion on Emerging Drugs, 2021
Landon L. Chan, Stephen L. Chan
There are several points to note with regard to recent phase III trials involving immune checkpoint inhibitors that have implications to clinical practice. First, it was observed that some patients could achieve durable responses with immune checkpoint inhibitor. Although not entirely predictive, PD-L1 expression is one of the few markers that allow clinicians to gauge the likelihood of response to immune checkpoint inhibitors in many cancers. Indeed, PD-L1 expression (≥1%, or in some cases ≥50%) is required for the use of immune checkpoint inhibitors in many cancer types, such as non-small-cell lung cancers [30], head and neck cancers [68], renal cell carcinoma [69] and breast cancer [70]. However, high PD-L1 expression has not been demonstrated to correlate with response in HCC [25,26,45,52]. Further research will be needed to explore the predictive value of PD-L1 expression, or other biomarkers for response, to identify the patient group who would benefit most from immune checkpoint inhibitors. Furthermore, unlike other cancers, HCC is most commonly diagnosed radiologically. Tumor biopsy is not usually recommended for diagnosis due to intrinsic hypervascularity of HCC. Therefore, there is a need to develop noninvasive biomarkers (e.g. blood-based or radiographical features) to predict response to immune checkpoint inhibitors.
Preoperative adrenal artery embolization followed by surgical excision of giant hypervascular adrenal masses: report of three cases
Published in Acta Chirurgica Belgica, 2018
Ismail Cem Sormaz, Fatih Tunca, Arzu Poyanlı, Yasemin Giles Şenyürek
The patient underwent DSA 24 h prior to the intervention. Angiography images showed that the right adrenal mass was predominantly fed by inferior phrenic artery. The inferior phrenic artery was selectively catheterized with 2.8 French microcatheter (Figure 3(a)) and embolized with polyzene-F hydrogel microspheres (six boxes of 1300 μm and one box of 1100 μm). At the end of the procedure, test imaging showed almost complete disappearance of tumor blush (Figure 3(b)). The patient was closely monitored at the ICU during the subsequent 24 h and had no symptoms associated with arterial embolization. The patient underwent surgical exploration via extended right subcostal incision and right adrenalectomy was performed. During the operation, we observed marked decrease in the hypervascularity of the tumor. The size of the vessels, especially veins, surrounding the adrenal tumor was found to be decreased when compared to preoperative imaging findings. No major blood loss occurred during the operation. The postoperative period was uneventful and the patient was discharged on the 5th postoperative day. The final histopathologic examination revealed perivascular epithelioid cell tumor (PEComa) and the largest diameter of the tumor was measured as 18 cm.