Natural History of Unruptured Visceral Artery Aneurysms Due to Segmental Arterial Mediolysis and Efficacy of Transcatheter Arterial Embolization: A Retrospective Multiinstitutional Study in Japan.

OBJECTIVE. The purpose of this study was to clarify the natural history of unruptured visceral artery aneurysms due to segmental arterial mediolysis and the efficacy of transcatheter arterial embolization. MATERIALS AND METHODS. Patients with a pathologic or clinical diagnosis of visceral artery aneurysms due to segmental arterial mediolysis between 2005 and 2015 were enrolled. For patients with clinical diagnoses, images were collected and assessed by central radiologic review. To clarify the natural history of unruptured aneurysms, the morphologic changes were assessed. The efficacy and safety of transcatheter arterial embolization for aneurysms due to segmental arterial mediolysis were evaluated. RESULTS. Forty-five patients with 123 aneurysms due to segmental arterial mediolysis were enrolled. Among the 123 aneurysms, 70 unruptured aneurysms were evaluated for natural history. Forty-five of the 70 (64%) aneurysms had no change in morphology. Among the other 25 aneurysms, nine (13% of the 70) were reduced in size, 13 (19%) disappeared, and three (4%) were newly found at follow-up. Aneurysms of the middle colic artery were ruptured in 10 of 11 (91%) cases. Transcatheter arterial embolization was performed on 45 aneurysms and was successful in all cases but caused slight arterial injury in three cases (6.7%). CONCLUSION. At initial diagnosis, unruptured aneurysms due to segmental arterial mediolysis are likely to be stable or to resolve, but the risk of rupture of aneurysms of the middle colic artery appears high. Transcatheter arterial embolization is a useful treatment, but careful manipulation is necessary.

Multicenter investigation of the incidence of inferior vena cava filter fracture.

PURPOSE: Inferior vena cava filter fracture (FF) may cause life-threatening complications, including cardiac tamponade, although the actual prevalence remains unclear. Therefore, we investigated the incidence of FF. MATERIALS AND METHODS: Data on fracture incidence with filter brands, filter positions [suprarenal (SR) vs. infrarenal (IR)], and follow-up durations were collected from the databases of eight hospitals. RESULTS: Of 532 patients, Günther Tulip (GT), Trap/OptEase (TE/OE), ALN and VenaTech (VT) were implanted in 345, 147, 38 and 2 patients, respectively. Of these, filter retrieval was attempted in 110 (21.7%) patients and was successful in 106 (96.4%). Of the remaining 426 patients, FFs were observed in two (0.7%) of 270 GT filters and 19 (14.1%) of 135 TE/OE filters. Fragment embolization occurred in one patient with a GT filter (50.0%) and three with a TE/OE filter (15.8%) with a total follow-up interval of 718.0 ± 1019.4 days. FF occurred more frequently in TE/OE than in GT filters (p < 0.001). Kaplan-Meier estimates showed significantly higher fracture-free rates for GT than TE/OE (p < 0.001) and IR-TE/OE than SR-TE/OE (p < 0.05). CONCLUSIONS: TE/OE filters are not suitable for permanent implantation due to the relatively early and high fracture rates.

The incidence of contrast-induced nephropathy (CIN) following transarterial chemoembolisation (TACE) in patients with hepatocellular carcinoma (HCC).

PURPOSE: The purpose of this retrospective study was to investigate the incidence of contrast-induced nephropathy (CIN) caused by transarterial chemoembolisation (TACE) in patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: One hundred forty-one patients treated between 2005 and 2008 undergoing 305 consecutive sessions of TACE were enrolled. CIN was defined as an increase in the serum creatinine level of more than 0.5 mg/dl or more than 25 % from baseline within 3 days after TACE without any other identifiable cause of acute kidney injury. RESULTS: CIN by the present definition was observed after 2.6 % of the TACE sessions. No patient showed clinical signs or symptoms of acute renal failure, or required haemodialysis. None of the patients with an estimated glomerular filtration rate of <60 ml/min/1.73 m(2) developed CIN. CONCLUSION: The present study suggests that TACE is a relatively safe procedure in terms of the risk of CIN under vigorous periprocedural hydration and that the incidence of CIN is comparable to that of AKI associated with intravenous CM administration. KEY POINTS: • CIN would be lower for non-coronary arterial intervention than for coronary intervention. • The present study suggests that the CIN rates following TACE are low. • The incidence of CIN is comparable to that after intravenous CM administration.

CT findings of small bowel strangulation: the importance of contrast enhancement.

The purpose of this study is to illustrate computed tomography (CT) findings suggestive of small bowel strangulation. We have performed the precontrast and postcontrast CT with single and multidetector CT scanners and evaluated the bowel wall changes and mesentery changes and correlated them with the operative findings. The direct CT findings suggestive of small bowel strangulation included high-density bowel wall on precontrast scans; lack of, or diminished contrast enhancement of the involved bowel wall; localized mesenteric fluid accumulation (mesenteric congestion); and localized pneumatosis. The indirect CT signs included C- or U-shaped loops with mesenteric vessels converging toward the obstruction site, ascites, target sign, two adjacent collapsed round loops, and whirl sign. We particularly emphasize the importance of contrast enhancement of bowel mucosa for early diagnosis to differentiate strangulation from a mechanical obstruction without bowel ischemia, and also the importance to differentiate proximal secondary gas-filled dilated small bowel loops from distal primary involved fluid-filled small bowel loops because these two types of small bowel loops are present in the single peritoneal cavity. As early recognition of small bowel strangulation may help improve the patient outcome because the involved bowel loops can be preserved without resection, it is essential to become familiar with the CT signs suggested small bowel obstruction strangulation.

Radiological diagnosis of large-bowel obstruction: neoplastic etiology.

Large-bowel obstruction (LBO) is a relatively common abdominal emergency. The CT exam has become the most important imaging modality for the diagnosis of LBO, following abdominal ultrasound and plain radiography. The recent multi-detector CT (MD-CT) is able to clarify the etiology of LBO and to help in deciding how to treat LBO. Therefore, it is important for the radiologists to become familiar with the imaging findings of LBO, including plain radiograph and CT, due to various causes. In this article, we have shown the characteristics of the radiological findings including plain radiograph, barium study, and CT as well as their correlations with pathologic findings of LBO. The etiology of LBO is usually divided into neoplastic diseases and nonneoplastic diseases. However, the most common cause is the neoplastic etiology. Now, we can afford the critical information concerning the level of obstruction, its cause, the viability of the involved bowel loops, and a decision-making regarding the therapy for patients with LBO, using MD-CT high technology.

Radiological diagnosis of large-bowel obstruction: nonneoplastic etiology.

Large-bowel obstruction (LBO) is a relatively common abdominal emergency. Computed tomography (CT) diagnosis of LBO is often easy, but it is essential to clarify LBO etiology and to decide how to treat it. Therefore, it is important for the radiologist to become familiar with the imaging findings of LBO, including plain radiography and CT, to determine its various causes, as well as the many diseases mimicking LBO. In this article, we show the characteristics of radiological findings of plain radiograph, barium study, and CT and their correlations with pathologic findings. LBO etiology comprises two main categories: neoplastic and nonneoplastic disease. However, the primary causes of LBO are neoplastic etiologies, and nonneoplastic causes are relatively uncommon and unfamiliar to many radiologists in clinical practice. Therefore, in this review, we present nonneoplastic etiology of LBO and diseases simulating LBO and provide critical information concerning the causes of LBO and viability of the involved bowel loops.

Body diffusion-weighted MR imaging of uterine endometrial cancer: is it helpful in the detection of cancer in nonenhanced MR imaging?

OBJECTIVE: In this study, the authors discussed the feasibility and value of diffusion-weighted (DW) MR imaging in the detection of uterine endometrial cancer in addition to conventional nonenhanced MR images. METHODS AND MATERIALS: DW images of endometrial cancer in 23 patients were examined by using a 1.5-T MR scanner. This study investigated whether or not DW images offer additional incremental value to conventional nonenhanced MR imaging in comparison with histopathological results. Moreover, the apparent diffusion coefficient (ADC) values were measured in the regions of interest within the endometrial cancer and compared with those of normal endometrium and myometrium in 31 volunteers, leiomyoma in 14 patients and adenomyosis in 10 patients. The Wilcoxon rank sum test was used, with a p<0.05 considered statistically significant. RESULTS: In 19 of 23 patients, endometrial cancers were detected only on T2-weighted images. In the remaining 4 patients, of whom two had coexisting leiomyoma, no cancer was detected on T2-weighted images. This corresponds to an 83% detection sensitivity for the carcinomas. When DW images and fused DW images/T2-weighted images were used in addition to the T2-weighted images, cancers were identified in 3 of the remaining 4 patients in addition to the 19 patients (overall detection sensitivity of 96%). The mean ADC value of endometrial cancer (n=22) was (0.97+/-0.19)x10(-3)mm(2)/s, which was significantly lower than those of the normal endometrium, myometrium, leiomyoma and adenomyosis (p<0.05). CONCLUSION: DW imaging can be helpful in the detection of uterine endometrial cancer in nonenhanced MR imaging.

Detection and evaluation of pelvic lymph nodes in patients with gynecologic malignancies using body diffusion-weighted magnetic resonance imaging.

BACKGROUND: In this study, the potential in detecting and evaluating pelvic lymph node metastases on body diffusion-weighted (DW) images was evaluated in patients with gynecologic malignancies. METHODS: This study included 18 patients with gynecologic malignancy who underwent magnetic resonance imaging in the pelvis using a 1.5-T superconductive magnet. The identification of pelvic nodes on only T2-weighted (T2W) axial images and on DW axial images in addition to T2W axial images was examined and compared. Moreover, we measured and calculated a short-axis diameter, a long-axis diameter, and a ratio of short- and long-axis diameter of nodes on the T2W images and the apparent diffusion coefficient (ADC) values of the nodes on the DW images. These results were compared with histopathologic results. RESULTS: First, 136 (40%) of 340 dissected nodes were identified on T2W images, and 249 (73%) of 340 dissected nodes were identified on DW images in addition to T2W images. Second, the differences in the short-axis diameter, the long-axis diameter, and the ratio of short- and long-axis diameter on T2W images between metastatic and nonmetastatic nodes were not significant. The differences in the ADC values between metastatic and nonmetastatic nodes were not significant. CONCLUSIONS: Body DW images are useful in detection of pelvic lymph nodes in patients with gynecologic malignancy. However, the measurement of ADC values does not contribute to a diagnosis of metastatic nodes.

Scheme for creating a subcutaneous tunnel to place an indwelling implantable central venous access system in the forearm.

We report a method that we have devised in which a secure subcutaneous tunnel is prepared during the placement of an indwelling central venous reservoir in the forearm. Subjects included 69 cases in which a procedure for implanting an indwelling reservoir in the forearm was performed between June 2006 and May 2007. For the subcutaneous tunnel, a 22-G Cathelin needle was advanced from the puncture site, turning toward the subcutaneous pocket side to the deep subcutaneous area. A 14-G Surflo IV catheter was then advanced along the 22-G Cathelin needle from the subcutaneous pocket. With the tip of the 14-G Surflo IV catheter emerging above the skin at the puncture site, the inner needle of the 14-G Surflo IV catheter and the 22-G Cathelin needle were removed. The catheter was passed through the outer 14-G Surflo IV catheter to emerge on the subcutaneous pocket site, then the outer needle of the Surflo catheter was also removed, and a connection to the port was made to create the subcutaneous tunnel. In all 69 cases, the subcutaneous tunnel in the forearm of the nondominant arm was successfully created within a short period of time (100% success rate). No problems were observed due to slack in the catheter until removal of the sutures 1 week later and for 3 months after treatment. With this method, we believe that a subcutaneous tunnel can be prepared in which the contained catheter has minimal freedom of movement, and which minimizes any damage induced by slack in the catheter within the subcutaneous tunnel.

Preoperative evaluation of local invasion and metastatic lymph nodes of colorectal cancer and mesenteric vascular variations using multidetector-row computed tomography before laparoscopic surgery.

OBJECTIVE: To evaluate local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations using multidetector-row computed tomography (MDCT) before laparoscopic colorectal surgery. METHODS: Fifty-one patients with colorectal cancer underwent MDCT. The evaluation items were as follows: (1) local invasion; (2) detected lymph nodes evaluated by short-axis diameter, long-axis diameter, short/long axis diameter ratio, and computed tomography (CT) attenuation; and (3) visualization of mesenteric artery and vein by 3-dimensional-CT angiography. RESULTS: First, in the evaluation of local invasion, overall accuracy was 94.1%. Second, the point of 0.8 or greater in short/long-axis diameter ratio was best index for the diagnosis of metastatic lymph nodes. Using this index, the accuracy of the diagnosis per node was 80.5%. Third, 3-dimensional-CT angiography correctly demonstrated variations of the mesenteric artery and vein. CONCLUSIONS: The MDCT was effective for evaluation of local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations before laparoscopic surgery.

Hepatic computed tomography for simultaneous depiction of hepatocellular carcinoma, intrahepatic portal veins, and hepatic veins in real-time virtual sonography: initial experience.

OBJECTIVE: The aim of this study was to examine a double-step injection of contrast material in hepatic computed tomography (CT) for the simultaneous depiction of hepatocellular carcinoma (HCC), intrahepatic portal veins, and hepatic veins in real-time virtual sonography. METHODS: This study consisted of 6 patients with solitary HCC nodules with early enhancement on dynamic contrast-enhanced CT. Computed tomographic scanning was performed in a combined late arterial/hepatic phase after 2 sequential contrast material injections. RESULTS: In all 6 patients, the solitary HCC nodule, intrahepatic portal veins, and hepatic veins were simultaneously visualized with enhancement, for which CT values were appreciably higher than that of the liver parenchyma. In virtual sonography, HCC nodules and intrahepatic vessels were simultaneously shown, and the HCC lesions were treated by radio frequency ablation without vascular injury. CONCLUSIONS: A double-step injection of contrast material in hepatic CT was helpful in the identification of the relationship between the HCC nodule and intrahepatic vessels under virtual sonography and contributed to the accurate and safe performance of radio frequency ablation for HCC.

Diffusion-weighted MR imaging for urinary bladder carcinoma: initial results.

The aim of this study was to demonstrate the feasibility of using diffusion-weighted (DW) magnetic resonance (MR) imaging under free breathing for the detection of a urinary bladder carcinoma. In 15 patients with 17 urinary bladder carcinomas, DW images were obtained in the axial plane under free breathing scanning with a multisection spin-echo type single-shot echo planar sequence with a body coil. DW images were evaluated based on cystoscopic findings. Moreover, the apparent diffusion coefficient (ADC) value was measured in a circular region of interest (ROI) within the carcinoma, urine, normal bladder wall, prostate and seminal vesicle. In the results, on the DW images, all 17 carcinomas were clearly shown as high signal intensity relative to the surrounding structure. The ADC value (x10(-3) mm(2)/s) in the carcinoma was 1.18+/-0.19, which was significantly lower compared with that of urine (3.28+/-0.20), the normal bladder wall (2.27+/-0.24), prostate (transition zone: 1.57+/-0.09, peripheral zone:1.85+/-0.22) and seminal vesicle (2.01+/-0.22). In conclusion, DW images under free breathing enabled the clear detection of the urinary bladder carcinoma, whose ADC values were lower compared with those of the surrounding structure. The DW images may be useful in evaluating tumors invading to the surrounding structures.

CT and MR features of sclerosing mesenteritis mimicking a mesenteric metastasis from the carcinoid tumor.

Sclerosing mesenteritis is a rare and benign inflammatory entity characterized by fibrofatty thickening of the mesentery. To our knowledge, there are only a few reports on the features of sclerosing mesenteritis on magnetic resonance (MR) imaging and computed tomography (CT). In this present case, MR imaging demonstrated tissue characterization of fibrosis, and partial maximum intensity projection (MIP) and three-dimensional angiography images obtained using multislice CT clearly revealed the extent of the tumor and the vascular appearance affected by the mass. However, a mesenteric metastasis from the carcinoid tumor may show such imaging features. Therefore, when encountering such a case, we suggest that a tentative diagnosis of sclerosing mesenteritis be made, followed by a biopsy for intraoperative histopathologic analysis to avoid aggressive surgery.

Dual-phase 3D CT angiography during a single breath-hold using 16-MDCT: assessment of vascular anatomy before laparoscopic gastrectomy.

OBJECTIVE: In this study, we evaluated the efficacy of dual-phase 3D CT angiography (CTA) during a single breath-hold using 16-MDCT in the assessment of vascular anatomy before laparoscopic gastrectomy. MATERIALS AND METHODS: The study involved 20 consecutive patients (10 men, 10 women; mean age, 59 years) scheduled for laparoscopic gastrectomy for the treatment of early gastric cancer. A dual-phase contrast-enhanced CT scan using 16-MDCT was obtained before laparoscopic gastrectomy. After rapid infusion of a nonionic contrast agent, arterial and venous phase scans were obtained serially with an interval of 15 sec during a single breath-hold of 31 sec. Three-dimensional CTA images in the arterial phase (3D CT arteriography) and venous phase (3D CT venography) were individually reconstructed using the volume-rendering technique, and then the images were fused together. We evaluated the detectability of the celiac trunk, left gastric artery (LGA), right gastric artery (RGA), left gastric coronary vein (LCV), Henle's gastrocolic trunk, right gastroepiploic vein (RGEV), and accessory right colic vein on 3D CTA to compare with surgical findings. RESULTS: In all 20 patients, 3D CT arteriography and venography clearly showed the celiac trunk, LGA, RGA, Henle's gastrocolic trunk, RGEV, and accessory right colic vein, which were correctly identified during surgery. The branching pattern of the celiac trunk was classified as Michels type I in 19 patients and Michels type II in one patient. Imaging showed the RGA originating from the proper hepatic artery (PHA) in nine patients; from the gastroduodenal artery (GDA) in seven patients; and from the left hepatic artery (LHA) in four patients. In 12 patients, the LCV joined the portal vein (PV) and in eight, the splenic vein (SV). In all patients, the accessory right colic vein joined the RGEV, and Henle's gastrocolic trunk proximal to the joining point flowed to the superior mesenteric vein (SMV). In all 20 patients, the fused image simultaneously showed arteries and veins around the stomach, with no mismatch between the arterial and venous phase images. In 10 patients, the LCV joined the PV after running along the dorsal side of the PHA, common hepatic artery (CHA), or splenic artery (SA). In eight patients, the LCV joined the SV after running along the ventral side of the PHA, CHA, or SA. In two patients, the LCV joined the PV after running along the ventral side of the CHA, which correlated with the surgical findings. Both the sensitivity and positive predictive values of 3D CTA revealed 100% correct identification of the celiac trunk, LGA, RGA, LCV, Henle's gastrocolic trunk, RGEV, and accessory right colic vein. CONCLUSION: Dual-phase 3D CTA using 16-MDCT clearly revealed individual arteries and veins around the stomach before laparoscopic gastrectomy. The fused image of 3D CT arteriography and venography during a single breath-hold enabled the simultaneous assessment of arteries and veins before laparoscopic gastrectomy.

Benign or malignant?: differentiating breast lesions with computed tomography attenuation values on dynamic computed tomography mammography.

OBJECTIVE: To evaluate enhancement effects of breast lesions with dynamic computed tomography (CT) and to determine characteristics to aid in differential diagnosis of benign and malignant lesions. METHODS: One hundred seventy-six women underwent preoperative dynamic CT, in which they were scanned with rapid injection of contrast media (3 mL/s) after 30 seconds and 2 minutes (early and delayed phases, respectively). The CT values and enhancement patterns of malignant lesions (n = 154) were compared with those of benign lesions (n = 22), and the cut point of CT values with the best validity was analyzed. RESULTS: The CT values of malignant lesions were higher than those of benign lesions in both phases (P < 0.0001). The cut point was determined to be 60 Hounsfield units (HU) in the early phase (44% validity, 90% sensitivity). Washout and plateau patterns were more commonly seen in the malignant group (73% specificity). CONCLUSIONS: The analysis of enhancement effects on CT may lead to more appropriate differentiation of benign and malignant lesions.

[A case of giant fibrovascular polyp of the esophagus: MR findings].

We report a case of giant fibrovascular polyp of the esophagus. The patient was a 69-year-old man who complained of hematemesis. Barium swallowing revealed a long, expansile lesion within the esophagus. Endoscopy demonstrated a pedunculated lesion covered with normal esophageal epithelium. On MRI, the sagittal image showed the characteristic sausage-like shape of the lesion. On T2-weighted images, the lesion demonstrated predominantly low signal intensity, which reflected a fibrous tumor. Opposed-phase imaging showed the area of decreased intensity within the mass, which reflected adipose tissue. MRI was useful for the differential diagnosis of fibrovascular polyp.

Accumulation of 99mTc-PMT in renal metastasis of hepatocellular carcinoma.

We describe here a case in which 99mTc-Sn-N-pyridoxy-5-methyltryptophan (99mTc-PMT) scintigraphy was useful in diagnosing renal metastasis of hepatocellular carcinoma (HCC). A 62-year-old man who had undergone hepatectomy for HCC presented 6 years after initial diagnosis with left flank pain and was found on CT and MRI to have a tumor in the left kidney. Hepatobiliary scintigraphy using 99Tc-PMT was performed, and 99mTc-PMT accumulation was found in the tumor. Nephrectomy was performed and metastasis of HCC was confirmed.

Three-dimensional CT angiography of the hepatic artery: use of multi-detector row helical CT and a contrast agent.

The administration of a contrast agent to obtain optimal images at three-dimensional computed tomographic (CT) angiography of the hepatic artery by using multi-detector row helical CT was investigated. Three-dimensional CT angiographic images were evaluated visually, and quantitative evaluation was performed by measuring the postcontrast CT number of the aorta. The injection rate of 5 mL/sec was significantly superior to that of 4 mL/sec in both evaluations. At administration of a contrast agent with 300 or 350 milligrams of iodine per milliliter, there were no significant differences in either evaluations. The preferable injection rate to obtain sufficient three-dimensional CT angiographic data was 5 mL/sec.