MR Imaging Findings of Traumatic Thoracic Aortic Injury

PURPOSE: To determine the magnetic resonance imaging (MRI) findings in patients with traumatic thoracic aortic injury and to assess the usefulness of MRI for the diagnosis of aortic injury. MATERIALS AND METHODS: Between May 1990 and June 2000, sixteen patients with blunt thoracic aortic injury underwent MRI. The findings were evaluated with regard to the type of aortic injury, aortic circumference, the size, direction and shape of the pseudoaneurysm, the intimal flap, and pseudocoarctation. Six patients underwent follow-up MRI, and any changes in the findings were assessed. RESULTS: MRI indicated that traumatic thoracic aortic injury comprised localized pseudoaneurysm in 15 patients and extensive aortic dissection in one. The aortic circumference was partially involved in all cases. Pseudoaneurysms were located at the aortic isthmus in 16 cases and the descending thoracic aorta in one. Two patients each had two lesions: two pseudoaneurysms in one, and aortic dissection and pseudoaneurysm in the other. The mean diameter and length of the pseudoaneurysms was 2.8+/-0.8 cm (mean+/-SD) and 3.3+/-1.0 cm (mean+/-SD), respectively. Their direction was anteromedial or anterolateral in 15 cases and posterolateral in two. All were saccular shaped. An intimal flap was present in seven cases and pseudocoarctation was demonstrated in ten. Follow-up MRI revealed changes in the size of a pseudoaneurysm or the length of an aortic dissection. CONCLUSION: The most common finding demonstrated by MRI in patients with traumatic thoracic aortic injury was an anteromedially-directed saccular pseudoaneurysm in the aortic isthmus. This modality was considered useful for evaluation of the entire aorta in cases of multiple pseudoaneurysms or aortic dissection.

CT Imaging Features of Phytobezoar Associated with Small Bowel Obstruction

PURPOSE: The purpose of this study was to evaluate the CT findings of phytobezoar associated with small bowel obstruction. MATERIALS AND METHODS: In 19 patients with phytobezoar associated with small bowel obstruction, two of whom had underlying small bowel disease, we analyzed the morphological characteristics of phytobezoars and changes in the bowel and perienteric regions, as revealed by abdominal Ct imaging. RESULTS: On CT, phytobezoars appeared as single or multiple, gas-containing masses in 17 patients (89%) and as a solid mass without gas in the remaining two (11%). An encapsulating wall was noted in six patients (32%). Among the 17 without underlying small bowel disease, the bowel wall was thickened in 13 (76%) at the obstructed site and/or the bowel proximal to the obstruction. Mesenteric vascular engorgement and haziness were seen in 18 patients (95%) and a small amount of ascites in six (32%). MR images of one patient showed the phytobezoar as a hypointense mass on all sequences. CONCLUSION: CT imaging is useful for the diagnosis of phytobezoar associated with small bowel obstruction.

Percutaneous Intravascular Metallic Stent Placement in Chronic Iliac Artery Stenoses

PURPOSE: To determine the long-term patency of percutaneous intravascular metallic stent placement in patients with chronic iliac artery stenosis. MATERIALS AND METHODS: Intravascular metallic stents were placed percutaneously in 41 limbs of 38 patients with chronic iliac artery stenosis who presented with intermittent claudication in 40 limbs and gangrene in the other. Preoperative angiography showed that complete occlusion occurred in one limb, and luminal stenosis of over 50% in 34 and of less than 50% in six. The mean length of stenoses was 3.1 (range, 1 -8) cm, and in all cases the systolic pressure gradient was over 10 (range, 12 -100, mean, 43) mmHg. Stent placement was indicated by failed balloon angioplasty in 35 limbs, primary stenting in five, and restenosis after balloon angioplasty in one. Technical and clinical success were evaluated in terms of immediate results and stent patency over a period of 1 -49 (mean, 19) months (Kaplan-Meier method). RESULTS: Stent placement was successful in all cases in which residual stenosis was less than 10% and systolic pressure gradient less than 2 mmHg. One to three days after the procedure, clinical symptoms had improved in 40 limbs and ABI (n=23) had increased from 0.64 +/-0.20 to 0.92 +/-0.17. Follow-up studies demonstrated patency rates of 94.1% at 6 months, 90.7% at 1 year, 86.6% at 2 years, and 86.6% at 4 years. CONCLUSION: Our results showed that in patients with chronic iliac artery stenosis, percutaneous intravascular metallic stent placement led to patency rates which were similar over a period of between six months and four years.

Usefulness of MR Imaging for Diseases of the Small Intestine: Comparison with CT

OBJECTIVE: To evaluate the usefulness of MR imaging for diseases of the small intestine, emphasizing a comparison with CT. MATERIALS AND METHODS: Thirty-four patients who underwent both CT and MR imaging using FLASH 2D and HASTE sequences were analyzed. All patients had various small bowel diseases with variable association of peritoneal lesions. We compared the detectabilities of CT and MR imaging using different MR pulse sequences. The capability for analyzing the characteristics of small intestinal disease was also compared. RESULTS: MR imaging was nearly equal to CT for detecting intraluminal or peritoneal masses, lesions in the bowel and mesentery, and small bowel obstruction, but was definitely inferior for detecting omental lesions. The most successful MR imaging sequence was HASTE for demonstrating bowel wall thickening, coronal FLASH 2D for mesenteric lesions, and axial FLASH 2D for omental lesions. MR imaging yielded greater information than CT in six of 12 inflammatory bowel diseases, while it was equal to CT in six of seven neoplasms and inferior in five of seven mesenteric ischemia. In determining the primary causes of 15 intestinal obstructions, MR imaging was correct in 11 (73%) and CT in nine (60%) patients. CONCLUSION: MR imaging can serve as an alternative diagnostic tool for patients with suspected inflammatory bowel disease, small intestinal neoplasm or obstruction. is a high-speed, heavily T2-weighted sequence with a great sensitivity for fluid (11). This advance may make it possible to use breath-hold turbo spin-echo MR.

Ultrasonic Measurement of the Extraocular Muscles: A Comparison with CT

PURPOSE: To compare the usefulness of orbital ultrasound measurements of extraocular muscle thickness with that of CT measurements in patients with thyroid ophthalmopathy. MATERIALS AND METHODS: Fourteen patients with thyroid ophthalmopathy underwent orbital ultrasound and CT scanning, and 19 normal volunteers underwent ultrasound. For orbital ultrasound, a 5-10 MHz small part probe was applied to bilateral closed eyelids. The medial and lateral rectus muscles were measured on transverse scan, and the superior rectus complex and inferior rectus muscles on longitudinal scan. On orbital CT, the medial and lateral rectus muscles were measured on axial scan, and the superior rectus complex and inferior rectus muscle on coronal scan. The maximum thickness of the belly of each muscle was measured on both ultrasound and CT. The ultrasound detection rates for each measurable muscle were assessed in both the thyroid ophthalmopathy and normal control group, and the statistical significance of the thickness of extraocular muscles measured by ultrasound and CT was evalvated. RESULTS: In patients with thyroid ophthalmopathy and in the normal control group, all medial and lateral rec-tus muscles were successfully measured by ultrasound. The detection rate for the superior rectus complex was 60.7 % in the thyroid ophthalmopathy group and 63.1% in the normal control group, and for the inferior rectus muscle, 78.6% and 39.5% in the two respective groups. A comparison of measurements of the thickness of extraocular muscle using orbital ultrasound and CT showed no statistically significant difference between the medial rectus muscle and the superior rectus complex, but a significant difference between the lateral and inferior rectus muscle. CONCLUSION: In these patients, all medial rectus muscles were easy measurable by ultrasound, and the thickness thus determined was not different from that determined by CT. Orbital ultrasound is thus a useful method for diagnosis and follow-up in patients with thyroid ophthalmopathy in whom the medial rectus mus-cle is thickened.

Ultrasonic Measurement of the Extraocular Muscles: A Comparison with CT

PURPOSE: To compare the usefulness of orbital ultrasound measurements of extraocular muscle thickness with that of CT measurements in patients with thyroid ophthalmopathy. MATERIALS AND METHODS: Fourteen patients with thyroid ophthalmopathy underwent orbital ultrasound and CT scanning, and 19 normal volunteers underwent ultrasound. For orbital ultrasound, a 5-10 MHz small part probe was applied to bilateral closed eyelids. The medial and lateral rectus muscles were measured on transverse scan, and the superior rectus complex and inferior rectus muscles on longitudinal scan. On orbital CT, the medial and lateral rectus muscles were measured on axial scan, and the superior rectus complex and inferior rectus muscle on coronal scan. The maximum thickness of the belly of each muscle was measured on both ultrasound and CT. The ultrasound detection rates for each measurable muscle were assessed in both the thyroid ophthalmopathy and normal control group, and the statistical significance of the thickness of extraocular muscles measured by ultrasound and CT was evalvated. RESULTS: In patients with thyroid ophthalmopathy and in the normal control group, all medial and lateral rec-tus muscles were successfully measured by ultrasound. The detection rate for the superior rectus complex was 60.7 % in the thyroid ophthalmopathy group and 63.1% in the normal control group, and for the inferior rectus muscle, 78.6% and 39.5% in the two respective groups. A comparison of measurements of the thickness of extraocular muscle using orbital ultrasound and CT showed no statistically significant difference between the medial rectus muscle and the superior rectus complex, but a significant difference between the lateral and inferior rectus muscle. CONCLUSION: In these patients, all medial rectus muscles were easy measurable by ultrasound, and the thickness thus determined was not different from that determined by CT. Orbital ultrasound is thus a useful method for diagnosis and follow-up in patients with thyroid ophthalmopathy in whom the medial rectus mus-cle is thickened.