Cervical contrast enhancement

The low-signal-intensity middle layer corresponds to the cervical stroma and mostly consists of connective tissue. The outer layer has a signal intensity that is comparable to that of the myometrium and is characterized by a more loose tissue structure [20] and may not always be distinguishable from the parametria even on T2-weighted images. The mucosa in the cervical canal shows the strongest enhancement and is thus clearly distinct from the less enhancing stromal layer. The outer stromal layer of the cervix and the portio also show contrast enhancement. 

In patients with locally advanced or recurrent cervical cancer, it is often necessary to exclude ureteral obstruction, which can be done on transverse T2-weighted images that also serve to assess the paraaortic lymph nodes. In addition, coronal T2-weighted turbo-spin echo (TSE) sequences enable excellent evaluation for possible urinary retention and require little extra time to acquire. In addition, contrast-enhanced MR urography can be performed to exclude tumor-induced hydronephrosis. 

Recurrent cervical cancer is associated with bone metastases (Fig. 7.39) in 15%-29% of patients at autopsy [ too, 103]. Typical locations are the bony pelvis as well as the lumbar and other vertebral bodies. Bone metastases in the ribs and extremities are less common. Skeletal metastases typically have an osteolytic character and originate from locally advanced or recurrent tumor in the pelvic sidewall or arise through retrograde tumor spread in patients with para-aor-tic lymph node metastasis [104]. Hematogenous dissemination to the skeleton occurs late. MRl with unenhanced and contrast-enhanced fat-saturated Tl-weighted sequences depicts bone metastases as hyperintense lesions in the low-intensity bone marrow with a high sensitivity. CT primarily shows the extent of osseous destruction. 

Postema S, Pattynama PM, van Rijswijk CS, TYimbos JB (1999) Cervical carcinoma can dynamic contrast-enhanced MR imaging help predict tumor aggressiveness Radiology 1999 210 217-220... 

The difficulty inherent to visualisation of squamous cell carcinoma of the head and neck by current imaging is that invariably there are soft tissue and hard tissue components of the disease. MRI is undoubtedly superior for imaging soft tissues and CT for bone. The introduction of FDG PET has helped clinicians to identify the inherent problem of the unknown primary. However it wasn t until co-registration with CT that more accurate analysis of the position was obtained. Analyses of PET/CT vs contrast-enhanced CT (Chen AY et al. 2006), the use of PET/CT to improve accuracy of initial cervical nodal staging 0eong et al. 2007) and the use of PET/CT for staging as well as surveillance of difficult areas such as skull base tumours have all been recently reported (Gil et al. 2007). 

Fig. 32.9. a T2-weighted MR scan showing cervical cancer with infiltration into the right parametric space (arrow), b Same patient in a contrast-enhanced CT scan. Due to the reduced soft tissue contrast, the infiltration of the parametric space (a) cannot be clearly delineated... 

Whole-body CT (WB-CT) protocols in multisystem trauma usually consist of a non-contrast enhanced head CT, which is followed by a contrast-enhanced chest and abdominal CT. For evaluation of the spine, reformations from the chest and abdomen are of diagnostic image quality if the primary colUmation was 2.5 mm or less, and dedicated scans of the spine are not obligatory (Mann et al. 2003). The cervical spine can be scanned separately with thin coUimations after the head scan, or can be included in the chest scan. The latter option has the advantage that the cervical vessels are contrast-enhanced, and vascular injuries can be ruled out from the same dataset, sparing one additional scan. 

These studies should always be performed with and without contrast enhancement and a bone windowed as well as a soft tissue windowed evaluation of the CT scan of the lesion should be done. Direct coronal images are indispensable in the presence of cervical or skull base mass lesion and 1 to 3 mm sections are required for the petrous temporal bone evaluation. Due to the hypervascularity of the paragangliomas, intense homogeneous enhancement of these tumors occurs following the contrast administration. 

Fig. 2.4. a Axial unenhanced cervical CT of a 16-year-old female shows a slightly hypodense mass containing a calcified phle-bolith in the left parotid region, b After contrast injection, the venous malformation slightly enhances, remains hypodense and is better delineated... 

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