# Nodes

Nodes

- Accurate assessment of  nodal involvement remains a chal - lenge for imaging. Most imaging techniques rely purely on size criteria to demonstrate lymph node involvement, with no possibility of  identifying micrometastases in normal-sized nodes. A size criterion of  8–10 /uni00A0 mm is often adopted, but it is not usually possible to distinguish benign reactive nodes from infiltrated nodes. This is a particular problem in patients with intrathoracic neoplasms, in whom enlarged benign reactive mediastinal nodes are common. The echo characteristics of  nodes at endoscopic ultrasound have been used in many centres to increase the accuracy of  nodal staging, and nodal sampling is possible via either mediastinoscopy or transoesoph ageal biopsy under endoscopic ultrasound control. PET/CT is of increasing use in detecting nodal metastases from a wide range of  malignancies, with the capacity to co-register the area of  increased FDG uptake with a precise anatomical location. No vel MRI contrast agents may help in the identification of non-enlarged tumour-infiltrated nodes. 

Figure 8.41
(a)
Endoscopic ultrasound in gastric cancer. The hypoechoic tumour (arrows) is in
/f_i
ltrating the layered structure of the gastric wall
and extending out beyond the serosa.
(b)
Computed tomography scan demonstrates thickening and enhancement of the gastric wall in the
same area (arrows). The stomach is distended with water to provide low-density contrast.

Nodes

- Accurate assessment of  nodal involvement remains a chal - lenge for imaging. Most imaging techniques rely purely on size criteria to demonstrate lymph node involvement, with no possibility of  identifying micrometastases in normal-sized nodes. A size criterion of  8–10 /uni00A0 mm is often adopted, but it is not usually possible to distinguish benign reactive nodes from infiltrated nodes. This is a particular problem in patients with intrathoracic neoplasms, in whom enlarged benign reactive mediastinal nodes are common. The echo characteristics of  nodes at endoscopic ultrasound have been used in many centres to increase the accuracy of  nodal staging, and nodal sampling is possible via either mediastinoscopy or transoesoph ageal biopsy under endoscopic ultrasound control. PET/CT is of increasing use in detecting nodal metastases from a wide range of  malignancies, with the capacity to co-register the area of  increased FDG uptake with a precise anatomical location. No vel MRI contrast agents may help in the identification of non-enlarged tumour-infiltrated nodes. 

Figure 8.41
(a)
Endoscopic ultrasound in gastric cancer. The hypoechoic tumour (arrows) is in
/f_i
ltrating the layered structure of the gastric wall
and extending out beyond the serosa.
(b)
Computed tomography scan demonstrates thickening and enhancement of the gastric wall in the
same area (arrows). The stomach is distended with water to provide low-density contrast.

Nodes

- Accurate assessment of  nodal involvement remains a chal - lenge for imaging. Most imaging techniques rely purely on size criteria to demonstrate lymph node involvement, with no possibility of  identifying micrometastases in normal-sized nodes. A size criterion of  8–10 /uni00A0 mm is often adopted, but it is not usually possible to distinguish benign reactive nodes from infiltrated nodes. This is a particular problem in patients with intrathoracic neoplasms, in whom enlarged benign reactive mediastinal nodes are common. The echo characteristics of  nodes at endoscopic ultrasound have been used in many centres to increase the accuracy of  nodal staging, and nodal sampling is possible via either mediastinoscopy or transoesoph ageal biopsy under endoscopic ultrasound control. PET/CT is of increasing use in detecting nodal metastases from a wide range of  malignancies, with the capacity to co-register the area of  increased FDG uptake with a precise anatomical location. No vel MRI contrast agents may help in the identification of non-enlarged tumour-infiltrated nodes. 

Figure 8.41
(a)
Endoscopic ultrasound in gastric cancer. The hypoechoic tumour (arrows) is in
/f_i
ltrating the layered structure of the gastric wall
and extending out beyond the serosa.
(b)
Computed tomography scan demonstrates thickening and enhancement of the gastric wall in the
same area (arrows). The stomach is distended with water to provide low-density contrast.