[CT colonography: patient preparation and examination technique]. / CT-Kolonographie: Patientenvorbereitung und Untersuchungstechnik.

An examination technique adapted to comply with the demands of CT colonography is not only a basic requirement for a high-quality examination and correct ascertainment of the findings; it is also essential for far-reaching applications of this method of examination. The technique of CT colonography is based on good patient preparation with the aid of fecal tagging, adequate distension of the colon with CO(2) and acquisition of data with the patient both prone and supine in a thin-slice technique using a low-dose protocol. The different technical aspects of CT colonography are explained in this paper.

Jaw fixation as the key to diagnosis of fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva is a very rare and disabling hereditary disorder of connective tissue characterised by symmetric congenital anomalies of the great toes and thumbs and by progressive heterotopic ossification of tendons, ligaments, fasciae and striated muscles. In this case we report a 17-year-old boy who presented with a painful swelling of the right mandibula with trismus. Multiple heterotopic soft tissue calcifications, severe scoliosis and typical anomalies of toes and thumbs on the radiographs were pathognomonic for fibrodysplasia ossificans progressiva.

Fibrolamellar hepatocellular carcinoma in a 65-year-old woman: CT features.

A 65-year old woman with recurrent deep vein thrombosis underwent a CT scan of the upper abdomen for detection of underlying malignancy. A fibrolamellar hepatocellular carcinoma with extrahepatic subdiaphragmatic satellite lesion was found. This uncommon tumor has distinct clinical, pathological, radiological and prognostic features and therefore it is important to distinguish it from benign liver tumors, especially FNH, and from other malignant liver tumors such as conventional HCC. Though the tumor characteristically occurs in younger patients, our case proves that older patients can also be affected.

Small bowel obstruction due to a persistent omphalomesenteric duct.

We report a case of a Meckel diverticulum connected with the umbilicus through a fibrotic cord causing small bowel obstruction. On admission, the patient presented with an acute abdomen. A plain upright radiography of the abdomen, an ultrasonography of the abdomen, and an enema with gastrografin were performed, showing a small bowel obstruction at the level of the pre-terminal ileum, without revealing the cause. Urgent surgery followed, showing a persistent omphalomesenteric duct connected to the abdominal wall through a fibrotic cord, with a secondary volvulus of the small bowel. The remnant was resected and the volvulus reduced. The post-operative course was uneventful. Because of the serious complications and even possible mortality due to ischemic disease of the affected small bowel the possibility of a complicated persistent omphalomesenteric duct should be kept in mind, even if the preoperative work-up does not reveal a Meckel diverticulum.

CT colonography with fecal tagging after incomplete colonoscopy.

The objective of this study was to evaluate dietary fecal tagging (FT) as a cleansing method prior to CT colonography (CTC) in patients with incomplete conventional colonoscopy (CC). After written informed consent was obtained, 24 patients had standard colonoscopic preparation (ScCl), and 25 patients had FT as cleansing method. Segmental distention, fluid levels, fecal residues, tagged appearance of fluid levels, and residual stool were evaluated. Mann-Whitney U test was used to test for significant differences between FT and ScCl groups. Compared with ScCl, FT improved distention (p=0.001), reduced the amount of fluid (p=0.043), but suffered from residual stool (p=0.046). A clear correlation was found between distention and fluid. No differences were found in stool size between FT and ScCl. FT showed a good labeling of fecal residues, and acceptable labeling of fluid levels. Compared with ScCl, FT reduces fluid, favors distention, but suffers from fecal residues. The tagged nature of these residues, however, allows differentiation from polyps.

Claudication type lower limb pain in an athlete without atherosclerotic risk factors: a case of cystic adventitial disease of the popliteal artery.

Cystic adventitial disease (CAD) of popliteal artery is a rare cause of lower limb claudication. Since its first description in 1947 only about 323 cases have been reported in the literature. We report the case of a 45 year old man with CAD of the popliteal artery causing progressive left lower leg claudication detected by US and Doppler US and characterized with spiral CT angiography. No communication with the knee joint could be demonstrated.

Optimisation of colon cleansing prior to computed tomographic colonography.

Colon preparation technique is a major determinant factor for patient compliance and polyp detection in computed tomographic colonography (CTC). The purpose of this study is to compare three different colon cleansing techniques in terms of patient discomfort, sensitivity and specificity. The following colon cleansing methods were compared in 20 patients each: 1. standard colonoscopy cleansing (ScCl) the day of the examination, based on polyethylene glycol (PEG), 2. a slightly reduced cleansing (RcCI) the day prior to the examination, based on a combination of diet, bisacodyl and a reduced intake of PEG, and 3. a cleansing with dietary fecal tagging (FT) the day prior to the examination, based on a combination of diet, bisacodyl, magnesium citrate and a dedicated barium suspension. ScCl resulted in a clean colon, but produces fluid levels hampering a complete CTC and possibly resulting in false negative diagnosis. RcCl reduced the problem of fluid levels, but was faced with the problem of fecal residues, resulting in false positive diagnosis. FT offered the possibility to obtain a dry colon, with labelled fecal residues, thus reducing false positive findings. Optimisation of the diet and replacement of PEG by magnesium citrate in FT reduced the preparation related discomfort and improved the final opinion. FT is the preferred colon cleansing technique because, compared to ScCl, fluid levels are reduced, and compared to RcCl, differentiation between faecal residues and polyps is improved. Moreover, FT reduces preparation related discomfort, compared to both RcCl and ScCl.

Septic arthritis of a lumbar facet joint caused by Staphylococcus aureus.

STUDY DESIGN: Case report of a 35-year-old woman with septic arthritis of a lumbar facet joint. OBJECTIVES: To report a rare case of severe low back pain and the specific differential diagnostic problems. SUMMARY OF BACKGROUND DATA: Differential diagnosis between spondylodiscitis and facet joint septic arthritis on a clinical basis is very difficult. The lesions of the joint appear on a plain film only approximately 1.5 months after onset of the symptoms. Although the radionuclide bone scan is sensitive and shows a more laterally and vertically localized uptake than in spondylodiscitis, this technique is not very specific. Computed tomography scan and magnetic resonance imaging are the most reliable investigations even at the very early stages of the disease. Confirmation of the diagnosis has to be obtained by blood cultures or, in exceptional cases, by direct puncture of the joint. Appropriate antibiotic treatment is in most cases sufficient to heal this lesion. METHODS: The etiology, clinical presentation, technical examinations, and treatment are reviewed. RESULTS: Computed tomography scan and magnetic resonance imaging complemented by positive blood cultures led to the very early diagnosis of septic arthritis of the lumbar facet joint in this relatively young patient. CONCLUSIONS: With our case report we confirm the very small number of data reported in the literature, indicating that infections of the facet joint can be detected at a very early stage using magnetic resonance imaging and computed tomography scan.

Percutaneous treatment of acute multiple limb ischemia.

This study evaluates the use of pulse spray pharmacomechanical thrombolysis (PSPMT) in combination with a low dose urokinase infusion and a possible secondary percutaneous treatment in the management of acute multiple limb ischemia. A retrospective analysis of 185 patients treated with PSPMT revealed eight patients with acute simultaneous ischemia of more than 1 limb. Seven patients presented with acute ischemia of both lower limbs; one patient presented with acute ischemia of the left arm and both lower limbs. All patients were treated using a combination of PSPMT and low dose urokinase infusion. The combination of PSPMT and low dose urokinase infusion was completely successful in 6 cases. In 1 patient with bronchogenic carcinoma PSPMT failed and immediate surgical thrombectomy was performed. In the other patient we obtained clot dissolution with thrombolysis in one leg, residual clots at the popliteal level in the other leg however had to be removed by surgical embolectomy. Embolism was the cause of the occlusion in 6 patients. Atherosclerotic disease appeared to be the underlying cause in the other 2 patients. Atherosclerotic disease was treated with balloon angioplasty and stenting. In the 8 patients with multiple limb ischemia, combination of PSPMT, low dose urokinase infusion, and possibly secondary treatment was useful and constituted a valuable alternative to open surgery. Acute occlusion of the abdominal aorta and acute leg ischemia have a high mortality and amputation rate with variable results in treatment. The use of thrombolysis has reduced the necessity of surgery in arterial occlusive disease and simplifies the treatment of native artery occlusion. Especially in patients with long and multi-level occlusions with poor outflow, thrombolysis seems to be the treatment of choice. In our analysis of 8 cases with acute multiple limb ischemia we review our experience with the combination of pulse spray pharmacomechanical thrombolysis (PSPMT), low dose continuous urokinase infusion and a possible subsequent percutaneous treatment of the obstructing lesion. The final purpose was to investigate if this combination is a successful and safe method in the treatment of acute multiple limb ischemia.

Diagnosis and treatment of expanding haematoma of the lateral abdominal wall after blunt abdominal trauma.

We report a rare case of an expanding post-traumatic lateral abdominal wall haematoma. A superselective arteriogram of the deep circumflex iliac artery showed extravasation from the ascending branch, urging emergency therapy. Microcoil and Gelfoam embolisation was successfully performed. Haematomas of the abdominal wall can be divided in the common rectus sheath haematomas and the rare haematomas of the lateral abdominal wall. Differentiating both entities is essential, since there is a strong difference in their vascular supply. The typical vascular supply of the lateral abdominal wall is discussed, with emphasis on the ascending branch of the deep circumflex iliac artery.

Intraperitoneal contrast material combined with CT for detection of peritoneal metastases of ovarian cancer.

OBJECTIVE: To determine the sensitivity and specificity of CT-peritoneography (CT-P) in detecting peritoneal carcinomatosis in primary or recurrent ovarian cancer. METHODS: Twenty-five patients were submitted to a standard abdominal CT (CT) as well as a computed tomography after intraperitoneal infusion of contrast material (CT-P). Twenty patients had ovarian masses clinically suspected to be malignant. In five patients with ovarian cancer who underwent prior debulking surgery, recurrent disease was suspected. RESULTS: In 21/25 patients an ovarian malignancy was histologically confirmed. During surgery peritoneal spread was found in 13 patients; only in 5 cases CT correctly suggested peritoneal metastases (sensitivity 38%). However, in 10/13 women CT-P indicated peritoneal spread, increasing the overall sensitivity from 38% to 77%. Sensitivity varied substantially according to the different abdominal areas, and was lowest in the left subphrenic space (25%). The sensitivity of CT-P was 71% and 72% in the right paracolic gutter and the pelvis, respectively. Sensitivity of CT-P was not found to be size-dependent, but was mainly related to the morphology of the lesions, with 100% sensitivity in nodular lesions, and only 21% sensitivity for flat peritoneal lesions. CT-P did not improve detection of omental metastases, and was not advantageous when ascites was present. Previous surgery reduced overall specificity from 80% to 57%. CONCLUSION: CT-P greatly improved the sensitivity of CT in the preoperative detection of peritoneal spread of ovarian malignancy. However, the technique failed to detect flat peritoneal metastases, and had a low specificity in patients with a history of prior abdominal surgery.

T2-weighted MR imaging of the uterus: comparison of optimized fast spin-echo and HASTE sequences with conventional fast spin-echo sequences.

OBJECTIVE: Our objective was to compare the value of a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence with optimized fast spin-echo and conventional fast spin-echo techniques in evaluation of the uterus. SUBJECTS AND METHODS: Optimized fast spin-echo imaging was compared with fast spin-echo and HASTE imaging, for both image quality and ability to assess the zonal anatomy of the uterus, in 40 volunteers. In optimized fast spin-echo imaging, the imaging time was reduced using partial-Fourier reconstruction, reducing the echo spacing, and increasing the echo train length. RESULTS: HASTE imaging offered the least motion artifact of all techniques. On optimized fast spin-echo imaging, motion artifacts were moderate to severe in 10% of patients. On fast spin-echo imaging, motion artifacts were moderate to severe in 40% of patients. Optimized fast spin-echo imaging was superior to the other two techniques in terms of anatomic sharpness and overall image quality. CONCLUSION: Although HASTE imaging offers the unique feature of providing images free of motion artifacts, optimized fast spin-echo imaging appears to be the preferred technique for T2-weighted imaging of the uterus.

Normal Vaterian sphincter complex: evaluation of morphology and contractility with dynamic single-shot MR cholangiopancreatography.

OBJECTIVE: The objective of this study was to assess the usefulness of dynamic single-shot MR cholangiopancreatography in the evaluation of the morphology and contractility of the normal Vaterian sphincter complex and to assess whether i.v. injection of glucagon can improve visualization. SUBJECTS AND METHODS: Sixty patients without signs of Vaterian sphincter complex dysfunction were studied. A fast single-shot MR imaging sequence was used to obtain 20 consecutive images of the Vaterian sphincter complex during successive episodes of breathholding. In patients of group A (n = 30), 10 images were obtained before and 10 after i.v. administration of a sphincter-relaxing agent (glucagon). In the patients of group B (n = 30), no glucagon was administered. The degree of visualization of the Vaterian sphincter complex was assessed. RESULTS: Overall, the morphology and contractility of the Vaterian sphincter complex was adequately assessed in 57 patients (95%). However, the number of repetitions required to obtain this result varied greatly (mean, seven; range, two to 18). Glucagon had no apparent effect on the visibility of the most distal portion of the common bile duct. CONCLUSION: Nonvisualization of the most distal portion of the common bile duct on MR cholangiopancreatography studies is a normal variant that can simulate disease. Obtaining serial breath-hold images using a single-shot technique is helpful to avoid diagnostic errors.

Nonalcoholic duct-destructive chronic pancreatitis: imaging findings.

OBJECTIVE: Nonalcoholic duct-destructive chronic pancreatitis is a new entity that should be distinguished from alcoholic chronic pancreatitis. The purpose of this study was to assess the imaging features of nonalcoholic duct-destructive chronic pancreatitis. CONCLUSION: Nonalcoholic duct-destructive chronic pancreatitis has characteristic CT and MR imaging features that include the presence of a focal or more diffuse mass causing either regular or irregular narrowing of the main pancreatic duct, the absence of parenchymal atrophy and significant ductal dilatation proximal to the site of stenosis, and the absence of extrapancreatic spread.

Localized benign fibrous mesothelioma mimicking a malignant tumor of the pleura.

A case of benign fibrous pleural mesothelioma is reported. Imaging studies as well as clinical features suggested malignant pleural mesothelioma. The lesion was judged resectable and no metastases were found. At surgery it was found to be a benign pleural fibrous mesothelioma. Because of the considerable overlap of imaging characteristics between the two entities, the authors conclude that determination of resectability rather than differentiation between benign and malignant mesothelioma should be the primary goal to be achieved by imaging techniques.

Dual-phase helical CT of the liver: value of an early-phase acquisition in the differential diagnosis of noncystic focal lesions.

OBJECTIVE: Contrast-enhanced helical CT images of the liver are usually obtained during the portal vein phase (PVP), during which the parenchyma achieves peak enhancement. The purpose of this study was to determine whether the addition of arterial-phase (AP) scans would lead to improved characterization of focal lesions. MATERIALS AND METHODS: We reviewed the CT appearance of 102 focal lesions with a proven diagnosis. In the first part of the study, we assessed whether the addition of AP scans influenced the diagnostic performance of the three observers. In the second part of the study, we analyzed the morphologic appearance revealed on CT scans of the different types of lesions in the AP and PVP. RESULTS: The addition of AP scans led to a significant increase in the number of correct diagnoses: 71 lesions (70%) were correctly diagnosed with CT scans in both the AP and the PVP, compared with 54 lesions (53%) correctly diagnosed with CT scans in the PVP alone (p < .01). The largest difference was observed in the diagnosis of focal nodular hyperplasia (FNH) and adenoma (16/24 correct diagnoses instead of 6/24) (p < .005). Conversely, AP images did not significantly contribute to the diagnosis of hemangiomas and metastases. The following morphologic features were seen much more often on AP scans than on PVP scans and had a high positive predictive value (PPV): spoke-wheel pattern (FNH; PPV, 100%), central feeding vessel (FNH; PPV, 100%), and heterogeneous appearance with hyperdense components (hepatocellular carcinoma; PPV, 75%). CONCLUSION: Our data show that the radiologists' evaluation of CT scans in both the AP and the PVP improves the differentiation of hepatocellular carcinoma and FNH from other types of hepatic neoplasms.