Serial CT Findings of Paragonimus Infested Dogs and the Micro-CT Findings of the Worm Cysts

OBJECTIVE: To investigate the serial CT findings of Paragonimus westermani infected dogs and the microscopic structures of the worm cysts using Micro-CT. MATERIALS AND METHODS: This study was approved by the committee on animal research at our institution. Fifteen dogs infected with P. westermani underwent serial contrast-enhanced CT scans at pre-infection, after 10 days of infection, and monthly thereafter until six months for determining the radiologic-pathologic correlation. Three dogs (one dog each time) were sacrificed at 1, 3 and 6 months, respectively. After fixation of the lungs, both multi-detector CT and Micro-CT were performed for examining the worm cysts. RESULTS: The initial findings were pleural effusion and/or subpleural ground-glass opacities or linear opacities at day 10. At day 30, subpleural and peribronchial nodules appeared with hydropneumothorax and abdominal or chest wall air bubbles. Cavitary change and bronchial dilatation began to be seen on CT scan at day 30 and this was mostly seen together with mediastinal lymphadenopathy at day 60. Thereafter, subpleural ground-glass opacities and nodules with or without cavitary changes were persistently observed until day 180. After cavitary change of the nodules, the migratory features of the subpleural or peribronchial nodules were seen on all the serial CT scans. Micro-CT showed that the cyst wall contained dilated interconnected tubular structures, which had communications with the cavity and the adjacent distal bronchus. CONCLUSION: The CT findings of paragonimiasis depend on the migratory stage of the worms. The worm cyst can have numerous interconnected tubular channels within its own wall and these channels have connections with the cavity and the adjacent distal bronchus.

CT Numbers of Liver and Spleen in Normal Children

PURPOSE: To determine the mean liver CT numbers, and differences between liver and spleen, and liver and back muscle CT numbers in normal children, and to correlate the findings with sex and age. MATERIALS AND METHODS: One hundred and five normal children aged 2-14 years underwent pre-contrast CT scanning. Mean CT numbers of the liver, spleen, and back muscles were calculated, as well as the differences in CT numbers between the liver and spleen (liver-spleen CT numbers), and between the liver and back muscles (liver-back muscles CT numbers). The results were correlated with age and sex. RESULTS: For all children, mean liver, spleen, and back muscle, and liver-spleen and liver-back muscle CT numbers were 70.22+/-6.51 HU, 53.28+/-3.0 HU, 58.31+/-3.57 HU, 17.13+/-6.57 HU, and 11.88+/-5.94 HU, respectively. Mean liver CT numbers and the difference between liver and spleen CT numbers were high in children aged less than seven, bet mean spleen and back CT numbers, and the difference between liver and back muscle CT numbers were not different by age. By sex, all the CT numbers did not vary according to age. The sex of a subject did not affect the CT number. CONCLUSION: The children's mean liver CT number was 70.22+/-6.51 HU and the difference between liver and spleen CT numbers was 17.13+/-6.57 HU. Younger children had higher liver CT and liver-spleen CT numbers than older children. No CT numbers varied according to sex.

Hepatocellular Carcinoma: Comparison Study on Detecting Tumor Vascularity among Various Imaging Techniques

PURPOSE: To compare the detectability of tumor vascularity using triphasic spiral CT, angiography, CT during hepatic arteriography(CTHA) and single-level dynamic CTHA(SLD-CTHA). MATERIALS AND METHODS: Seventy-nine pathologically confirmed nodular hepatocellular carcinomas(HCCs) in 77 patients were included in this study. Sixty patients were male and 17 were female, and their ages ranged from 31 to 77 (average, 57.4) years. HCCs were classified into three groups according to the size: less than 2 cm (n=20), 2 -4 cm (n=32), and more than 4 cm (n=27) in diameter. If a portion of tumor demonstrated greater enhancement than surrounding liver parenchyma, vascularity was deemed to be present. Detectability by each imaging technique was compared according to size and overall. RESULTS: Hypervascularity was frequently detected by SLD-CTHA [90.9%(40/44)], followed by CTHA[88.0%(66/75)], angiography [80.3%(61/76)], triphasic spiral CT [72.4%(42/58)]. In the less than 2 cm group, detectability rates for triphasic spiral CT, angiography, CTHA and SLD-CTHA were 53.3%(8/15), 55.6%(10/18), 76.5%(13/17) and 87.5%(6/7), respectively. while the 2 -4 cm group demonstrated corresponding figures of 71.4%(15/21), 78.1%(25/32), 84.4%(27/32) and 86.4%(19/22). In the more than 4 cm group, the rate for triphasic spiral CT was 86.4%(19/22), while for angiography, CTHA and dynamic CTHA, it was 100%. CONCLUSION: In the detection of hypervascularity of HCC, SLD-CTHA showed the highest rate, followed by CTHA, angiography, and triphasic spiral CT. In HCCs less than 4 cm in diameter, the corresponding ordering was SLD-CTHA, CTHA, angiography and triphasic spiral CT, but in HCCs of more than 4 cm, angiography, CTHA and SLD-CTHA detected hypervascularity equally well. Lesion size most affected the findings of angiography.

The Usefulness of 0.5 %-Methylcellulous as Oral Contrast Agent: In Subtotal Gastrectomy Patients

PURPOSE: To assess the usefulness of 0.5 %-methylcellulose as oral contrast agent in spiral CT examinationsfor the evaluation of anastomotic site and remnant stomach in patients who have undergone subtotal gastrectomy dueto stomach cancer. MATERIALS AND METHODS: Twenty-seven patients who underwent subtotal gastrectomy for stomachcancer and were referred for the evaluation of anastomosis recurrence and lymph node metastasis wereprosepectively analyzed by spiral CT. They were divided into two groups: before scanning, group A patients drank0.5 %-methylcellulous 500ml as oral contrast agent, while those in group B drank diluted gastrografin 500ml. Threepatients were examined twice. Anatomic delineation of the anastomosis site was graded by two radiologists asexcellent (3), good (2), fair (1), or poor (0). To evaluate the degree of distension, maximal transverse andanterior-posterior diameter of remnant stomach and anastomotic sites were measured. RESULTS: In Group A, anatomicdelineation of the anastomotic site was very much better than in group B (mean score: 2.93 vs 1.80, p<0.05). Inaddition, the maximum diameters of remnant stomach and anastomotic site were significantly larger in group A thanin group B (transverse A-P remnant stomach and anastomosis site: 87.5 +/-14.7mm, 103.3 +/-20.1mm, 17.6 +/-2.9mm vs57.6 +/-20.1mm, 69.9 +/-3 5 . 0 m m , 10.7 +/-7 . 2 m m ) CONCLUSION: In patients who had undergone subtotalgastrectomy, the use of 0.5 %-methylcellulose as oral contrast agent for spiral CT showed excellent anatomicdelineation of the anastomotic site and distension of remnant stomach.

CT Angiography in Patients with Spontaneous Intracerebral Hematoma

PURPOSE: The purpose of this study was to assess the usefulness of CT angiography(CTA) in patients withintracerebral hematoma. MATERIALS AND METHODS: Eighteen patients with spontaneous intracerebral hematoma underwentCTA ; 20-30 seconds after the onset of an injection of contrast media(100mL, with the use of a power injector, ata rate of 3 mL/sec), Scanning(30-second continuous exposure and 60-90mm length) was performed with a table speedof 2-3 mm/sec and section thickness of 2mm. The starting point selected was the floor of the sella turcica. Theresulting data were reformatted by maximum intensity projection(MIP) after reconstruction at 1-mm intervals, andCTA findings were compared with those of conventional angiography(n=17), surgery(n=6), and postcontrast CT(n=10). RESULTS: The diagnostic findings of CTA included five arteriovenous malformations, two aneurysms, one venousangioma, and one venous sinus occlusion, while the remaining nine patients had no vascular lesion. In all cases,CTA findings correlated well with those of conventional angiography and surgery ; in four cases, they weresuperior to those of postcontrast CT. In one cases of arteriovenous malformation, however, the feeding artery anddraining vein were not definite on CTA, and in one case of sinus occlusion, the full length of the superiorsagittal sinus could not be delineated. CONCLUSION: In patients with spontaneous intracerebral hematoma, CTA is avaluable screening method.

The Usefulness of Levin Tube Inserted Drip Infusion Spiral CT: Comparison with Conventional Method in SubtotalGastrectomy Patients

PURPOSE: To access the usefulness of newly designed Leven tube inserted drip infusion spiral CT for theevaluation of remnant stomach and anastomosis site in patients who have undergone subtotal gastrectomy for stomachcancer. MATERIAL AND METHODS: A new technique named Levin tube inserted drip infusion spiral CT was used toprospectively study 23 patients. A 16Fr Levin tube was inserted into the remnant stomach ; 500ml of tap water wasdrip infused just before CT scanning and an additional 500ml of water was infused during IV contrast injection.Water was infused by gravity, using a water bottle suspended at a height of 90cm(Group A). The 31 patients whounderwent conventional spiral CT scanning immediately after the divided ingestion of 900ml diluted gastrografinwere selected as a control group(Group B). The anatomic delineation of the anastomosis site was graded by tworadiologists as excellent(3), good(2), fair(1) or poor(0). To evaluate the degree of distension, the maximaldiameters of remnant stomach and the anastomosis site, and the thickness of the stomach wall, were also measured. RESULTS: In group A, anatomic delineation of the anastomosis site was excellent, compared to group B(mean score:2.91 vs 1.19, P<0.01). In addition, the maximum diameters of remnant stomach and anastomosis site weresignificantly larger in group A than in group B(transverse A-P remnant stomach and anastomosis site : 92.4+/-16.0mm, 97.6+/-26.5mm, 29.7+/-7.3mm vs 50.6+/-12.9mm, 53.5+/-14.4mm, 7.7+/-4.4mm, P<0.01). The mean thickness of distended stomach wallin group A was 3.2+/-1.7mm ; in group B, measurement was possible in only a few cases, but their number was too smallfor comparison. CONCLUSION: In patients who had undergone subtobal gastrectomy, Levin tube inserted drip infusionspiral CT showed excellent anatomic delineation of the site of anastomosis and remnant stomach. We found thatbecause it increases the distension of remnant stomach and the anastomosis site, this technique is effective forthe evaluation of postoperative stomach.

The Difference of Nodule Detection Rates in the Liver According to the Pitch and Slice Thickness in Spiral CT: Experimental Study by Using Artificial Liver Phantom

PURPOSE: To determine optimal pitch and slice thickness when detecting small hepatoma by spiral CT. MATERIAL AND METHODS: Three types of artificial liver phantom of 45, 65, and 85 HU using agarose and three types ofartifical nodules of cheese with 95 HU of CT attenuation (5, 10 and 15mm in diameter) were prepared. After thethree types of phantom were embedded with three kinds of artificial nodules of different sizes, nine types ofphantom were made. In addition, four more 10-HU artificial liver phantoms embedded with 5-mm nodules were made.After the phantoms were scanned by spiral CT at different slice thicknesses (5, 8 and 10mm) and different pitches(1.0, 1.25, 1.5 and 2.0), nodule detection rates were determined ; these rates were, in addition, determined afteroverlapping reconstruction and changes in CT attenuation according to pitch. RESULT: Regardless of size, pitchand slice thickness, all nodules with more than 30 HU difference between the embedded nodule and artificial liverphantom were detected. The detection rate of 5mm nodules with a density difference of 10 HU decreased at a pitchof 2.0 and at 10mm slice thickness. After overlapping reconstruction, detection rates increased and there were noCT attenuation differences according to pitch. CONCLUSION: Eight-mm slice thickness is preferred and for thedetection of a nodule by spiral CT, pitch should not be greater than 1.5. After overlapping reconstruction,additional nodules were detected.

Imaging of the Jaw Cysts with a Dental CT Software Program: Distinction of Odontogenic Keratocysts from Other Cysts

PURPOSE: To evaluate the usefulness of a dental CT software program in the assessment of jaw cysts and in the differentiation of odontogenic keratocysts and other cysts. MATERIALS AND METHODS: Seventeen patients with proven jaw cysts (8 maxillae & 9 mandibles) were evaluated with a dental CT software program for location, locularity, the presence or absence of marginal scalloping, and height to length ratio. For the delineation of involvement or displacement of neurovascular bundles, cortical erosion, perforation or expansion, and tooth root resorption by the jaw cysts, images from this program were compared to conventional images. RESULTS: Seventeen lesions icomprised 15 odontogenic cysts (five odontogenic keratocysts, five radicular, three residual and two dentigerous cysts) and two non-odontogenic cysts (one nasopalatine duct cyst and one postoperative maxillary cyst). Images of jaw cysts obtained with the dental CT software program delineated much more clearly than conventional images the status of neurovascular bundle and cortical bone, but there was no clear difference between the two modalities in delineating tooth root erosion. Dental CT findings of five mandibular odontogenic keratocysts were scalloped margin in all, mandibular ramus involvement in four, height to length ratio below 60% in four, and multilocularity in two. The findings of the other 12 cysts (eight maxillae and four mandibles) were unilocularity in all, smooth inner margin in ten, height to length ratio below 60% in only two, and ramus involvement in none. CONCLUSION: Adental CT software program is an improved imaging modality for assessing jaw cysts ; and findings which tend to indicate odontogenic keratocysts are marginal scalloping, mandibular ramus involvement, prominent spread along the marrow space and multilocularity.

Carcinoma of Ampulla of Vater: Emphasis on the CT Technique

PURPOSE: To demonstrate a CT technique by which carcinoma of the ampulla of Vater can be more accurately diagnosed, and to describe the radiologic findings this carcinoma. MATERIALS AND METHODS: We retrospectively reviewed CT findings in 26 patients with pathologically proven carcinoma of the ampulla of Vater. One additional cup of diluted oral contrast medium was ingested immediately before the scan. We analysed the difference in detection rate of the mass in the duodenal lumen with and without duodenal luminal opacification of gastrografin.We also evaluated the size and shape of the mass, dilatation of CBD and the pancreatic duct, and lymph node metastasis. In addition, we analyzed multimodality imaging findings ultrasonogram (US) : 13; hypotonic duodenogram (HTDG): 7; ERCP : 17) of carcinoma of the ampulla of Vater. RESULTS: Nodular soft tissue masses protruding into the duodenal lumen were identified in 21 of 26 cases. In 95% of cases (21/22) with favorable opacification and distension of the duodenum, masses were clearly identified on CT imaging. However, in four caseswith poor opacification and distension of the duodenum, masses could not be observed(P=0.000). The mass on CT scanshowed a well-defined margin, round or lobulated contour, and contrast enhancement similar to that of thepancreas. CBD dilatation was identified in 20 cases and pancreatic duct dilatation in 12. On US, protruding massesin the distal CBD were observed in nine of 13 cases(60%) and on HTDG, in six of seven cases(86%). as well-definedfilling defects. Conclusion : Since the accuracy of CT diagnosis of intestinal lesions is directly proportional tothe degree of intestinal distension and opacification with oral contrast, we believe that adequate ct techniquefor distending and opacitying the duodeual lumen are necessary for early diagnosis of carcinoma of the ampulla ofVater.

Usefulness of CT Angiography in Patients with Intracranial Occlusive Vascular Disease of the Circle of Willis: Comparison with Conventional Angiography

PURPOSE: To assess the usefulness of CT angiography(CTA) compared with compared with conventional angiography(CA) in the evaluation of intracranial occlusive vascular disease. MATERIALS AND METHODS: We evaluated 26 patients with clinically suspected intracranial occlusive vascular disease studied with both CTA and CA. Incases where there was no vascular lesion on CA, we used CTA to retrospectively review the detection rate and size of individual vessels, and compared the findings with those obtained by CA. In cases of occlusive vascular lesion, we evaluated the degree of stenosis on CTA and compared this with the CA findings. We also measured the time taken to use both modalities. RESULTS: Sixteen patients had no vascular lesion and ten patients had occlusive vascularlesions. Compared with CA, CTA detected 97%(124/128) of normal intracranial arteies ; their diameter measured on CTA was slightly smaller than that on CA. On CTA, the degree of stenosis was correctly estimated in eight lesions, underestimated in one and overestimated in one. Examination time ranged between 15 and 20 minutes with CTA and between 40 and 60 minutes with CA. CONCLUSION: Compared with CA, CTA shows good correlation in the delineation of intracranial normal and occlusive vessels around the Circle of Willis. CTA may be an additional tool for the evaluation of the Circle of Willis in patients with suspected intracranial occlusive vascular disease. CTA may, additionally, be used as a follow-up method in patients with acute cerebral infarctions after thrombolytic therapy.