CT contrast-enhanced

Miller DL, Simmons JT, Chang (1987) Hepatic metastasis detection. Comparison of three CT contrast enhancement methods. Radiology 165 785... 

Norton GA, Kishore PR, Lin J (1978) CT contrast enhancement in cerebral infarction. Am J Roentgenol 131 881-885 Olah L, Wecker S, Hoehn M (2000) Secondary deterioration of apparent diffusion coefficient after 1-hour transient focal cerebral ischemia in rats. J Cereb Blood Flow Metab 20 1474-1482... 

Fig. 8.5 Haemangioma (see arrow). Dynamic CT (contrast-enhanced) portal venous phase (s. figs. 6.15 8.9 36.6, 36.7)...

The frequency of extravasation of ionic and non-ionic contrast media during rapid bolus injection in 5106 CT contrast-enhanced scans was 0.9% (31 patients had extravasation of ionic media and 17 patients had extravasation of non-ionic media) (273). There was no correlation between the injection rate and the frequency of extravasation. None of the patients who had extravasation had permanent damage. 

Contrast enhancement has not been described as a characteristic feature of cavernomas of the CNS in the CT era. Because of the improved contrast resolution of MRI (compared to CT), contrast enhancement is much more visible. However, MRI does not overcome the problem created by the slow blood exchange between the normal blood and the dilated cavernous vessels. Specifically with fast Tl-weighted sequences it is necessary to delay the interval between contrast agent injection and the start of the scanning procedure. 

Fig. 15.8. APN and CT. Contrast-enhanced CT triangularshaped areas of decreased enhancement corresponding to the diseased parenchyma...

Peripheral enhancement of the lesion followed by a central enhancement on contrast CT Contrast enhancement of the lesion on delayed scans (Freeny and Marks 1986)... 

Lacomis JM, Baron RL, Oliver JH, et al (1997) Cholangiocarcinoma delayed CT contrast enhancement patterns. Radiology 203 98-104... 

The amount of contrast material required for CTA is comparable to that used for conventional contrast-enhanced CT imaging. The amount of scanning time required for a CTA examination of the head and neck, such as is usually performed for acute... 

Contrast-enhanced computed tomography (CT) is used to identify the cause of pancreatitis and confirm the diagnosis. Magnetic resonance imaging is used to grade the severity of AP and identify bile duct abnormalities not seen on CT. Ultrasonography is useful to determine pancreatic enlargement and peripancreatic fluid collections. 

A possible way to improve differentiation between normal and diseased tissues is the use of non-specific contrast agents which achieve contrast enhancement based on morphological and physiological properties of tumour tissue. Contrast agents for X-ray, CT and MRI are preferentially taken up by tumour tissue shortly after intravenous injection due to increased tumour vasculature, leaky endothelial structures and enlarged extracellular volumes [34], a phenomenon that is in principle exploitable for optical contrast agents. 

Currently, contrast-enhancing helical CT is considered a mainstay in detecting a suspected pancreatic mass and determining its resectability (35). Many studies have confirmed the accuracy of helical CT in predicting resectability, with a resectability rate approaching 80% (36). 

Although contrast medium has been found to aggravate acute pancreatitis in animal models, some recent studies proved the safety of contrast-enhanced CT in humans (U3, H9). 

Fig. 2. Plain computed tomography (CT) 22 h after the administration of contrast medium. Wedge-shaped contrast enhancement was observed in the bilateral kidneys (From [1], with permission)...

Fig. 6. Delayed CT 48 h after the administration of contrast medium. The serum creatinine level was high (5.5mg/dl), and the contrast-enhanced areas were more extensive than those in Fig. 2 (serum creatinine 1.6mg/dl). Patchy contrast enhancement changed to diffuse contrast enhancement...

Fig. 8. Dynamic CT in the presence of wedge-shaped contrast enhancement (0 s)...

The area of wedge-shaped contrast enhancement increased with the increase in serum creatinine level. When the serum creatinine level exceeded 5 or 6 mg/dl, diffuse contrast enhancement involved the entire kidney. However, even in patients with diffuse contrast enhancement, delayed CT confirmed patchy wedge-shaped contrast enhancement again when the serum creatinine level decreased to 1.2-3.5 mg/dl in the recovery phase (refer to Patient 2 in Fig. 59, Chap. 10, Sect. 1). This finding in the recovery phase cannot be explained by tubular obstruction. 

In order to compare kidney function between the areas where contrast persisted and those where contrast did not persist, we performed additional dynamic CT in a patient with wedge-shaped contrast enhancement [14] (Fig. 14, Patient 3). 

Subsequently, we examined whether it is only patients with exercise-induced acute renal failure (ALPE) who show wedge-shaped contrast enhancement [15-18]. We performed delayed CT on a patient with ALPE and a patient with myoglobin uric acute renal failure (due to a malignant syndrome) when their serum creatinine levels were 3.0 and 1.5mg/dl, and compared the results. Wedge-shaped contrast enhancement was observed only in the patient with ALPE (Patient 19), and not in the patient with myoglobinuric acute renal failure. Diffuse contrast enhancement was noted (serum creatinine level, 3mg/dl) (Fig. 17). 

Wedge-shaped contrast enhancement on plain CT from a few hours to 72 h after the administration of a contrast medium (however, delayed CT after administration of the contrast medium is not essential to making a diagnosis). 

This patient was the first case in our series in which acute renal failure developed after an athletics meeting. After he had participated in a 200-m race, loin pain occurred, leading to acute renal failure. Delayed computed tomography (CT) showed diffuse to patchy contrast enhancement. The details are given in Chap. 2, Sect. 2. 

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