Imaging techniques

Imaging techniques

On ultrasonography , an abscess cavity in the liver is seen as a - hypoechoic or anechoic lesion with ill-defined borders; internal echoes suggest necrotic material or debris ( Figure 6.1 ). The - investigation is very accurate and is used for aspiration, both - diagnostic and therapeutic. When there is doubt about the diagnosis, a computed tomography (CT) scan may be helpful ( Figure 6.2 ). Diagnostic aspiration is of limited value exce pt for estab - lishing the typical colour of the aspirate, which is sterile and odourless unless it is secondarily infected. A CT scan may show a raised right hemidiaphragm, a pleural e ff usion and evidence of pneumonitis ( Figure 6.3 ) . - An ‘apple-core’ deformity on barium enema would arouse suspicion of a carcinoma. A colonoscopy with biopsy is man - datory because the radiological and macr oscopic appearance may be indistinguishable from a carcinoma. In doubtful cases, vigorous medical treatment is given and the pa tient undergoes colonoscopy again in 3–4 weeks, as these masses are known to regress completely on a full course of drug therapy . If symp toms persist even partially following full medical treatment in a patient who has recently returned from an endemic area, a colonic carcinoma must be excluded forthwith. This is because a dormant colonic carcinoma may become apparent as a result of infestation with amoebic dysentery causing ‘traveller’s diar rhoea’. However, it must be borne in mind that an amoeboma and a carcinoma can coexist. Summary box 6.2 Diagnostic pointers for infection with Entamoeba histolytica /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF

Figure 6.1 Ultrasound of the liver showing a large amoebic liver abscess with necrotic tissue in the right lobe. Bloody mucoid diarrhoea in a patient from an endemic area or following a recent visit to such a country Upper abdominal pain, fever, cough, malaise In chronic cases, a mass in the right iliac fossa may be an amoeboma but caecal cancer must be excluded by colonoscopy and biopsy Sigmoidoscopy shows typical ulcers – biopsy and scrapes may be diagnostic Serological tests are highly sensitive and speci /f_i c outside endemic areas Ultrasonography and CT scans are the imaging methods of choice

Imaging techniques

On ultrasonography , an abscess cavity in the liver is seen as a - hypoechoic or anechoic lesion with ill-defined borders; internal echoes suggest necrotic material or debris ( Figure 6.1 ). The - investigation is very accurate and is used for aspiration, both - diagnostic and therapeutic. When there is doubt about the diagnosis, a computed tomography (CT) scan may be helpful ( Figure 6.2 ). Diagnostic aspiration is of limited value exce pt for estab - lishing the typical colour of the aspirate, which is sterile and odourless unless it is secondarily infected. A CT scan may show a raised right hemidiaphragm, a pleural e ff usion and evidence of pneumonitis ( Figure 6.3 ) . - An ‘apple-core’ deformity on barium enema would arouse suspicion of a carcinoma. A colonoscopy with biopsy is man - datory because the radiological and macr oscopic appearance may be indistinguishable from a carcinoma. In doubtful cases, vigorous medical treatment is given and the pa tient undergoes colonoscopy again in 3–4 weeks, as these masses are known to regress completely on a full course of drug therapy . If symp toms persist even partially following full medical treatment in a patient who has recently returned from an endemic area, a colonic carcinoma must be excluded forthwith. This is because a dormant colonic carcinoma may become apparent as a result of infestation with amoebic dysentery causing ‘traveller’s diar rhoea’. However, it must be borne in mind that an amoeboma and a carcinoma can coexist. Summary box 6.2 Diagnostic pointers for infection with Entamoeba histolytica /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF

Figure 6.1 Ultrasound of the liver showing a large amoebic liver abscess with necrotic tissue in the right lobe. Bloody mucoid diarrhoea in a patient from an endemic area or following a recent visit to such a country Upper abdominal pain, fever, cough, malaise In chronic cases, a mass in the right iliac fossa may be an amoeboma but caecal cancer must be excluded by colonoscopy and biopsy Sigmoidoscopy shows typical ulcers – biopsy and scrapes may be diagnostic Serological tests are highly sensitive and speci /f_i c outside endemic areas Ultrasonography and CT scans are the imaging methods of choice

Imaging techniques

On ultrasonography , an abscess cavity in the liver is seen as a - hypoechoic or anechoic lesion with ill-defined borders; internal echoes suggest necrotic material or debris ( Figure 6.1 ). The - investigation is very accurate and is used for aspiration, both - diagnostic and therapeutic. When there is doubt about the diagnosis, a computed tomography (CT) scan may be helpful ( Figure 6.2 ). Diagnostic aspiration is of limited value exce pt for estab - lishing the typical colour of the aspirate, which is sterile and odourless unless it is secondarily infected. A CT scan may show a raised right hemidiaphragm, a pleural e ff usion and evidence of pneumonitis ( Figure 6.3 ) . - An ‘apple-core’ deformity on barium enema would arouse suspicion of a carcinoma. A colonoscopy with biopsy is man - datory because the radiological and macr oscopic appearance may be indistinguishable from a carcinoma. In doubtful cases, vigorous medical treatment is given and the pa tient undergoes colonoscopy again in 3–4 weeks, as these masses are known to regress completely on a full course of drug therapy . If symp toms persist even partially following full medical treatment in a patient who has recently returned from an endemic area, a colonic carcinoma must be excluded forthwith. This is because a dormant colonic carcinoma may become apparent as a result of infestation with amoebic dysentery causing ‘traveller’s diar rhoea’. However, it must be borne in mind that an amoeboma and a carcinoma can coexist. Summary box 6.2 Diagnostic pointers for infection with Entamoeba histolytica /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF

Figure 6.1 Ultrasound of the liver showing a large amoebic liver abscess with necrotic tissue in the right lobe. Bloody mucoid diarrhoea in a patient from an endemic area or following a recent visit to such a country Upper abdominal pain, fever, cough, malaise In chronic cases, a mass in the right iliac fossa may be an amoeboma but caecal cancer must be excluded by colonoscopy and biopsy Sigmoidoscopy shows typical ulcers – biopsy and scrapes may be diagnostic Serological tests are highly sensitive and speci /f_i c outside endemic areas Ultrasonography and CT scans are the imaging methods of choice