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Recent advances in lymphatic imaging have provided novel insights into the lymphatic system. Interventional radiology has played a significant role in the development of lymphatic imaging techniques and modalities. Radiologists should be familiar with the basic physiology and anatomy of the lymphatic system to understand the imaging features of lymphatic disorders, which reflect their pathophysiology. This study comprehensively reviews the physiological and anatomical aspects of the human lymphatic system as well as the latest lymphatic imaging techniques.
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Lymphatic disorders encompass a broad spectrum of diseases involving the lymphatic system, ranging from traumatic lymphatic leaks to lymphatic malformations. Lymphatic disorders can be categorized into traumatic and non-traumatic disorders according to their etiology. These two categories may be further divided into subgroups depending on the anatomical location of the lymphatic pathology and their association with clinical syndromes. Thoracic duct embolization was a milestone in the field of lymphatic intervention that encouraged the application of percutaneous embolization techniques to treat leaks and reflux disorders in the lymphatic system. Additional access routes for embolization, including retrograde thoracic duct and transhepatic lymphatic access, have also been developed. This article comprehensively reviews a variety of options for the treatment of lymphatic disorders, from conservative management to the most recent embolization techniques.
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Adventitial cystic disease (ACD) is a rare, non-atherosclerotic disease that mainly affects the popliteal artery. Treatment is primarily surgical as endovascular approaches are affected by high recurrence rates. However, some studies have reported successful endovascular treatments of popliteal ACD cases. A 55-year-old female presented with right calf claudication. Computed tomography angiography revealed segmental occlusion of the right distal superficial femoral artery. Subsequently, a drug-eluting stent was successfully deployed. However, an unusual adventitial cystic lesion occluding the lumen that was characteristic of ACD was detected during a postoperative imaging review. It was aspirated using an ultrasound-guided percutaneous needle and drained using a pigtail catheter for 24 hours. Follow-up images after 39 months showed a patent artery with no recurrence of any cystic lesions, highlighting successful ACD treatment via stenting, ultrasound-guided aspiration, and cyst drainage. Stenting and cyst aspiration can be an alternative option for selected patients with ACD.
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Common bile duct (CBD) stones are prevalent in 11% to 21% of patients with gallstones and can cause various clinical manifestations, from biliary colic to biliary sepsis. The treatment of choice is endoscopic retrograde cholangiopancreatography, but approximately 5% to 10% of CBD stones are difficult to remove using these conventional endoscopic methods. Although percutaneous transhepatic cholangioscopy and lithotripsy can be used as an alternative, it can be technically demanding and risky if the intrahepatic duct is not dilated. We report a case of a large CBD stone that was successfully removed using percutaneous transcholecystic cholangioscopy.
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Objective@#To assess the two-year treatment outcomes of chemoembolization with drug-eluting embolics (DEE) for nodular hepatocellular carcinoma (HCC). @*Materials and Methods@#This study was a prospective, multicenter, registry-based, single-arm trial conducted at five university hospitals in Korea. Patients were recruited between May 2011 and April 2013, with a target population of 200. A DC Bead loaded with doxorubicin was used as the DEE agent. Patients were followed up for two years. Per-patient and perlesion tumor response analysis, per-patient overall survival (OS) and progression-free survival (PFS) analysis, and per-lesion tumor control analysis were performed. @*Results@#The final study population included 152 patients, with 207 target lesions for the per-lesion analysis. At one-month, six-month, one-year, and two-year per-patient assessments, complete response (CR) rates were 40.1%, 43.0%, 33.3%, and 19.6%, respectively. The objective response (OR) rates were 91.4%, 55.4%, 35.1%, and 19.6%, respectively. The cumulative two-year OS rate was 79.7%. The cumulative two-year PFS rate was 22.4% and the median survival was 9.3 months. In multivariable analysis, the Child-Pugh score (p = 0.019) was an independent predictor of OS, and tumor multiplicity (p < 0.001), tumor size (p = 0.020), and Child-Pugh score (p = 0.006) were independent predictors of PFS. In per-lesion analysis, one-month, six-month, one-year and two-year CR rates were 57.5%, 58.5%, 45.2%, and 33.3%, respectively, and the OR rates were 84.1%, 65.2%, 46.6%, and 33.3%, respectively. The cumulative two-year per-lesion tumor control rate was 36.2%, and the median time was 14.1 months. The Child-Pugh score (p < 0.001) was the only independent predictor of tumor control. Serious adverse events were reported in 11 patients (7.2%). @*Conclusion@#DEE chemoembolization for nodular HCCs in the Korean population showed acceptable survival, tumor response, and safety profiles after a two-year follow-up. Good liver function (Child-Pugh score A5) was a key predictor of per-patient OS, PFS, and per-lesion tumor control.
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Objective@#To assess the two-year treatment outcomes of chemoembolization with drug-eluting embolics (DEE) for nodular hepatocellular carcinoma (HCC). @*Materials and Methods@#This study was a prospective, multicenter, registry-based, single-arm trial conducted at five university hospitals in Korea. Patients were recruited between May 2011 and April 2013, with a target population of 200. A DC Bead loaded with doxorubicin was used as the DEE agent. Patients were followed up for two years. Per-patient and perlesion tumor response analysis, per-patient overall survival (OS) and progression-free survival (PFS) analysis, and per-lesion tumor control analysis were performed. @*Results@#The final study population included 152 patients, with 207 target lesions for the per-lesion analysis. At one-month, six-month, one-year, and two-year per-patient assessments, complete response (CR) rates were 40.1%, 43.0%, 33.3%, and 19.6%, respectively. The objective response (OR) rates were 91.4%, 55.4%, 35.1%, and 19.6%, respectively. The cumulative two-year OS rate was 79.7%. The cumulative two-year PFS rate was 22.4% and the median survival was 9.3 months. In multivariable analysis, the Child-Pugh score (p = 0.019) was an independent predictor of OS, and tumor multiplicity (p < 0.001), tumor size (p = 0.020), and Child-Pugh score (p = 0.006) were independent predictors of PFS. In per-lesion analysis, one-month, six-month, one-year and two-year CR rates were 57.5%, 58.5%, 45.2%, and 33.3%, respectively, and the OR rates were 84.1%, 65.2%, 46.6%, and 33.3%, respectively. The cumulative two-year per-lesion tumor control rate was 36.2%, and the median time was 14.1 months. The Child-Pugh score (p < 0.001) was the only independent predictor of tumor control. Serious adverse events were reported in 11 patients (7.2%). @*Conclusion@#DEE chemoembolization for nodular HCCs in the Korean population showed acceptable survival, tumor response, and safety profiles after a two-year follow-up. Good liver function (Child-Pugh score A5) was a key predictor of per-patient OS, PFS, and per-lesion tumor control.
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Objective@#To assess the safety and efficacy of lymphopseudoaneurysm (LPA) glue (n-butyl cyanoacrylate [NBCA]) embolization in the management of chylous ascites after retroperitoneal surgery. @*Materials and Methods@#A retrospective analysis from January 2014 to October 2018 was performed in six patients (4 females and 2 males; mean age, 45.3 ± 14.2 years; range, 26–61 years) who underwent LPA embolization for chylous ascites developing after retroperitoneal surgery involving the perirenal space (four donor nephrectomies, one partial nephrectomy, and one retroperitoneal lymphadenectomy). After placing a percutaneous drainage catheter into the LPA or adjacent lymphocele, embolization was performed by filling the LPA itself with a mixture of glue and Lipiodol (Guerbet). @*Results@#Daily drainage from percutaneously placed drains exceeded 300 mL/day despite medical and surgical treatment (volume: mean, 1173 ± 1098 mL; range, 305–2800 mL). Intranodal lymphangiography was performed in four of the six patients and revealed leakage in 2 patients. Percutaneous embolization of the LPA was successful in all patients using an NBCA and Lipiodol mixture in a ratio of 1:1–1:2 (volume: mean, 4.3 ± 1.1 mL; range, 3–6 mL). Chylous ascites was resolved and the drainage catheter was removed in all patients within 4 days after the procedure (mean, 2.0 ± 1.8 days; range, 0–4 days). No procedure-related complications or recurrence of chylous ascites occurred during a mean follow-up period of 37.3 months (range, 21.1–48.4 months). @*Conclusion@#Glue embolization of LPA has the potential to be a feasible and effective treatment method for the management of chylous ascites after retroperitoneal surgery.
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OBJECTIVE: This study proposes a novel reference standard for hypervascular hepatocellular carcinomas (HCCs), established by cone-beam computed tomography-hepatic arteriography (CBCT-HA) and two-year imaging follow-up, and discusses its clinical implication on tumor staging and understanding the intrahepatic distant recurrence (IDR) in relation to dynamic computed tomography (CT).MATERIALS AND METHODS: In this retrospective study, 99 patients were enrolled, who underwent CBCT-HA during initial chemoembolization for HCC suspected on CT. All patients underwent chemoembolization and regular clinical and imaging follow-up for two years. If IDR appeared on follow-up imaging, initial CBCT-HA images were reviewed to determine if a hypervascular focus pre-existed at the site of recurrence. Pre-existing hypervascular foci on CBCT-HA were regarded as HCCs in initial presentation. Initial HCCs were classified into three groups according to their mode of detection (Group I, detected on CT and CBCT-HA; Group II, additionally detected on CBCT-HA; Group III, confirmed by interval growth). We assessed the influence of CBCT-HA and two-year follow-up on initial tumor stage and calculated the proportion of IDR that pre-existed in initial CBCT-HA.RESULTS: A total of 405 nodules were confirmed as HCCs, and 297 nodules initially pre-existed. Of the initial 297 HCCs, 149 (50.2%) lesions were in Group I, 74 (24.9%) lesions were in Group II, and the remaining 74 (24.9%) lesions were in Group III. After applying CBCT-HA findings, 11 patients upstaged in T stage, and 4 patients had a change in Milan criteria. Our reference standard for HCC indicated that 120 of 148 (81.1%) one-year IDR and 148 of 256 (57.8%) two-year IDR existed on initial CBCT-HA.CONCLUSION: The proposed method enabled the confirmation of many sub-centimeter-sized, faintly vascularized HCC nodules that pre-existed initially but clinically manifested as IDR. Our reference standard for HCC helped in understanding the nature of IDR and the early development of HCC as well as the clinical impact of tumor staging and treatment decision.
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Humans , Angiography , Carcinoma, Hepatocellular , Follow-Up Studies , Methods , Neoplasm Staging , Recurrence , Retrospective StudiesABSTRACT
Postoperative chylothorax is a rare occurrence after various thoracic surgical procedures,but it poses a substantial risk of morbidity and mortality. Thoracic duct embolization (TDE)is currently deemed the optimal treatment due to its safety and efficacy. This review offersan introduction to interventional options in this setting, detailing the steps of TDE for theedification of those engaged in postoperative care.
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Non-variceal upper gastrointestinal bleeding (NVUGIB) refers to bleeding that develops in the gastrointestinal tract proximal to the ligament of Treitz. NVUGIB is an important cause for visiting the hospital and is associated with significant morbidity and mortality. Although European and Asian-Pacific guidelines have been published, there has been no previous guidelines regarding management of NVUGIB in Korea. Korea is a country with a high prevalence of Helicobacter pylori infection and patients have easy accessibility to receive endoscopy. Therefore, we believe that guidelines regarding management of NVUGIB are mandatory. The Korean Society of Gastroenterology reviewed recent evidence and recommends practical management guidelines on NVUGIB in Korea.
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Nonvariceal upper gastrointestinal bleeding (NVUGIB) refers to bleeding that develops in the gastrointestinal tract proximal to the ligament of Treitz. NVUGIB requires hospitalization and is associated with significant morbidity and mortality.Although European and Asian-Pacific guidelines have been published, there have been no previous guidelines regarding management of NVUGIB in Korea. Korea has a high prevalence of Helicobacter pylori infections, and patients have easy accessibility to endoscopy. Therefore, we believe that guidelines regarding management of NVUGIB in Korea are essential. The Korean Society of Gastroenterology reviewed the recent evidence and recommends practical management guidelines on NVUGIB in Korea.
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Purpose@#To evaluate the safety and efficacy of the newly designed open-cell type self-expandable nitinol stent (NiTi-stent) for peripheral arteries. @*Materials and Methods@#Twenty-eight limbs of 14 minipigs were randomly assigned to the NiTistent group or conventional nitinol stent group. Stents were symmetrically implanted into the iliac arteries of each animal using carotid artery approach and were observed for 1 month (n = 5) and 6 months (n = 9). The angiographic lumen diameter (ALD), late lumen loss, angiographic stenosis, histomorphometric lumen area, neointimal area, and area stenosis were analyzed and compared between the groups. @*Results@#Stent migration, stent fracture, or thrombus formation were not observed in either group. At the 1-month follow-up, the neointimal area (p = 0.008) and area stenosis (p = 0.016) were significantly smaller in the NiTi-stent group than in the control group. At the 6-months followup, the NiTi-stent group showed significantly larger ALD (p = 0.014), less late lumen loss (p = 0.019), less angiographic stenosis (p = 0.014), larger lumen area (p = 0.040), and smaller neointimal area and area stenosis (p = 0.004 and p= 0.014, respectively) compared with the control group. @*Conclusion@#The NiTi-stent is as safe and effective as the conventional nitinol stent and induces less neointimal hyperplasia in a minipig iliac artery model.
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Inferior vena cava filters (IVCFs) are effective in preventing pulmonary embolism and their usage has rapidly increased over the past decades. However, complications have also significantly increased, as IVCF occlusion causes serious chronic venous insufficiency. Herein, we report a case of infrarenal IVCF occlusion that was successfully treated with the introduction of kissing stents through the IVCF into both iliac veins. A 54-year-old male presented with non-healing ulcers on his left leg. He had undergone IVCF implantation and warfarin medication due to deep vein thrombosis 4 years earlier in another hospital. Computed tomography (CT) revealed the filter-bearing IVC occlusion. Endovascular IVCF removal was attempted but failed. Kissing stents were deployed across the IVCF and extended into both iliac veins. Cone beam CT showed well-deployed stents just behind the occluded IVCF. Venous flow was restored without complications, and the recurrent ulcer healed immediately.
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PURPOSE: To evaluate clinical characteristics of pediatric nontraumaitc chylothorax and to suggest appropriate therapeutic managements. METHODS: We retrospectively reviewed medical records of 22 patients with nontraumatic chylothorax from January 2005 to December 2018 in the Children's Hospital of Seoul National University. We analyze their etiology, treatment, complications and outcome. RESULTS: Of the 22 patients, 16 were diagnosed before 1 year old and 6 after 1 year old. The causes of chylothorax under 1-year-old children were related to congenital factors (n=9), unknown causes (n=5), and high central venous pressure (n=2). The causes of chylothorax over 1-year-old children were related to congenital factors (n=3), unknown causes (n=1), high venous pressure (n=1), and lymphoma (n=1). All patients had dietary modification. Eight of them were cured by dietary modification, but there was no improvement in over 1-year-old children. Medication was added to patients refractory to dietary modification. Four patients with medication were improved and 5 were improved by surgical management. Nutritional, immunological and other complications occurred in many patients. Five death cases were reported. Four patients were under 1 year old and 1 was over 1 year old. The causes of nontraumatic chylothorax in dead patients were high central venous pressure (n=3), congenital (n=1), and unknown (n=1). CONCLUSION: Nontraumatic chylothorax more frequently occurs in under 1-year-old children. The most common cause is congenital factors. Stepwise management is effective in many patients, but specific treatment is needed in some cases. The prognosis is related to the onset of age and underlying diseases.
Subject(s)
Child , Humans , Central Venous Pressure , Chylothorax , Diet , Feeding Behavior , Lymphoma , Medical Records , Pediatrics , Prognosis , Retrospective Studies , Seoul , Venous PressureABSTRACT
PURPOSE: The AFX2 endograft is a unibody, bifurcated stent graft that can be used to lower complications in certain patients. In this study, we retrospectively reviewed consecutive cases in which the AFX2 system was used to overcome the challenges of narrow distal aorta, as well as to reduce procedure time and contrast medium dose. Furthermore, we compared the results with matched patients treated using the Endurant II endograft system.MATERIALS AND METHODS: This was a retrospective observational study of nine patients with abdominal aortic aneurysm (AAA) who underwent endovascular aneurysm repair (EVAR) using the AFX2 device between June 2017 and April 2018 at Seoul National University Hospital. The patients had narrow distal aorta (n=3), reversed tapered neck (n=1), iliac artery aneurysm (n=2), chronic kidney disease patients (n=2), and impending rupture (n=1). Seven matched patients were treated using the Endurant II graft.RESULTS: In the AFX2 group, the mean procedure time was 87.2 minutes, mean blood loss volume was 157.7 mL, and mean volume of contrast medium used was 48.3 mL. In the Endurant II group, the mean procedure time was 140.0 minutes, mean blood loss volume was 175.0 mL, and mean volume of contrast medium used was 119.3 mL.CONCLUSION: Our preliminary experiences with selected AAA patients treated using the AFX2 endovascular repair system showed good outcomes compared with similar patients treated using the Endurant II system. Therefore, the AFX2 may be a good option to perform EVAR in patients of advanced age who have chronic kidney failure or narrow distal aorta.
Subject(s)
Humans , Aneurysm , Aorta , Aortic Aneurysm , Aortic Aneurysm, Abdominal , Blood Vessel Prosthesis , Iliac Artery , Kidney Failure, Chronic , Neck , Observational Study , Renal Insufficiency, Chronic , Retrospective Studies , Rupture , Seoul , TransplantsABSTRACT
OBJECTIVE: To determine the efficacy of retrievable metallic stent with fixation string for benign anastomotic stricture after upper gastrointestinal (UGI) surgery. MATERIALS AND METHODS: From June 2009 to May 2015, a total of 56 retrievable metallic stents with fixation string were placed under fluoroscopy guidance in 42 patients who were diagnosed with benign anastomotic stricture after UGI surgery. Clinical success was defined as achieving normal regular diet (NRD). RESULTS: The clinical success rate after the first stent placement was 57.1% (24/42). After repeated stent placement and/or balloon dilation, the clinical success rate was increased to 83.3% (35/42). Six (14.3%) patients required surgical revision to achieve NRD. One (2.4%) patient failed to achieve NRD. Stent migration occurred in 60.7% (34/56) of patients. Successful rate of removing the stent using fixation string and angiocatheter was 94.6% (53/56). Distal migration occurred in 12 stents. Of the 12 stents, 10 (83.3%) were successfully removed whereas 2 could not be removed. No complication occurred regarding distal migration. CONCLUSION: Using retrievable metallic stent with a fixation string is a feasible option for managing early benign anastomotic stricture after UGI surgery. It can reduce complications caused by distal migration of the stent.
Subject(s)
Humans , Constriction, Pathologic , Diet , Fluoroscopy , Reoperation , Stents , Upper Gastrointestinal TractABSTRACT
OBJECTIVE: To test the hypothesis that a safety margin may affect local tumor recurrence (LTR) in subsegmental chemoembolization. MATERIALS AND METHODS: In 101 patients with 128 hepatocellular carcinoma (HCC) nodules (1-3 cm in size and < or = 3 in number), cone-beam CT-assisted subsegmental lipiodol chemoembolization was performed. Immediately thereafter, a non-contrast thin-section CT image was obtained to evaluate the presence or absence of intra-tumoral lipiodol uptake defect and safety margin. The effect of lipiodol uptake defect and safety margin on LTR was evaluated. Univariate and multivariate analyses were performed to indentify determinant factors of LTR. RESULTS: Of the 128 HCC nodules in 101 patients, 49 (38.3%) nodules in 40 patients showed LTR during follow-up period (median, 34.1 months). Cumulative 1- and 2-year LTR rates of nodules with lipiodol uptake defect (n = 27) and those without defect (n = 101) were 58.1% vs. 10.1% and 72.1% vs. 19.5%, respectively (p < 0.001). Among the 101 nodules without a defect, the 1- and 2-year cumulative LTR rates for nodules with complete safety margin (n = 52) and those with incomplete safety margin (n = 49) were 9.8% vs. 12.8% and 18.9% vs. 19.0% (p = 0.912). In multivariate analyses, ascites (p = 0.035), indistinct tumor margin on cone-beam CT (p = 0.039), heterogeneous lipiodol uptake (p = 0.023), and intra-tumoral lipiodol uptake defect (p < 0.001) were determinant factors of higher LTR. CONCLUSION: In lipiodol chemoembolization, the safety margin in completely lipiodolized nodule without defect will not affect LTR in small nodular HCCs.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Carcinoma, Hepatocellular/diagnostic imaging , Chemoembolization, Therapeutic , Cone-Beam Computed Tomography , Ethiodized Oil/administration & dosage , Follow-Up Studies , Liver Neoplasms/diagnostic imaging , Multivariate Analysis , Neoplasm Recurrence, Local/diagnostic imagingABSTRACT
OBJECTIVE: To evaluate the safety and clinical outcomes of chemoembolization in Child-Pugh class C patients with hepatocellular carcinomas (HCC). MATERIALS AND METHODS: The study comprised 55 patients with HCC who were classified as Child-Pugh class C and who underwent initial chemoembolization between January 2003 and December 2012. Selective chemoembolization was performed in all technically feasible cases to minimize procedure-related complications. All adverse events within 30 days were recorded using the Common Terminology Criteria for Adverse Events (CTCAE). The tumor response to chemoembolization was evaluated using the modified Response Evaluation Criteria In Solid Tumors. RESULTS: Thirty (54.5%) patients were within the Milan criteria, and 25 (45.5%) were beyond. The mortality of study subjects at 30 days was 5.5%. Major complications were observed in five (9.1%) patients who were all beyond the Milan criteria: two hepatic failures, one hepatic encephalopathy, and two CTCAE grade 3 increases in aspartate aminotransferase/alanine aminotransferase abnormality. The mean length of hospitalization was 6.3 ± 8.3 days (standard deviation), and 18 (32.7%) patients were discharged on the next day after chemoembolization. The tumor responses of the patients who met the Milan criteria were significantly higher (p = 0.014) than those of the patients who did not. The overall median survival was 7.1 months (95% confidence interval: 4.4-9.8 months). CONCLUSION: Even in patients with Child-Pugh class C, chemoembolization can be performed safely with a selective technique in selected cases with a small tumor burden.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Alanine Transaminase/metabolism , Aspartate Aminotransferases/metabolism , Carcinoma, Hepatocellular/mortality , Chemoembolization, Therapeutic/adverse effects , Hepatic Encephalopathy/etiology , Length of Stay , Liver Neoplasms/mortality , Liver Transplantation , Proportional Hazards Models , Severity of Illness Index , Survival Rate , Treatment Outcome , Tumor BurdenABSTRACT
OBJECTIVE: To evaluate the feasibility of percutaneous access via the recanalized paraumbilical vein for varix embolization. MATERIALS AND METHODS: Between July 2008 and Jan 2014, percutaneous access via the recanalized paraumbilical vein for varix embolization was attempted in seven patients with variceal bleeding. Paraumbilical vein puncture was performed under ultrasonographic guidance, followed by introduction of a 5-Fr sheath. We retrospectively evaluated the technical feasibility, procedure-related complications, and clinical outcomes of each patient. RESULTS: Recanalized paraumbilical vein catheterization was performed successfully in all patients. Gastroesophageal varix embolization was performed in six patients, and umbilical varix embolization was performed in one patient. Embolic materials used are N-butyl cyanoacrylate (n = 6) and coil with N-butyl cyanoacrylate (n = 1). There were no procedure-related complications. One patient underwent repeated variceal embolization 6 hours after initial procedure via recanalized paraumbilical vein, due to rebleeding from gastric varix. CONCLUSION: Percutaneous access via the paraumbilical vein for varix embolization is a simple alternative in patients with portal hypertension.
Subject(s)
Adult , Child , Female , Humans , Male , Middle Aged , Embolization, Therapeutic , Enbucrilate/therapeutic use , Esophageal and Gastric Varices/diagnostic imaging , Intracranial Hemorrhages/etiology , Retrospective Studies , Tomography, X-Ray Computed , Treatment Outcome , Umbilical Veins/surgeryABSTRACT
OBJECTIVE: To investigate whether the low-tube-voltage (80-kVp), intermediate-tube-current (340-mAs) MDCT using the Iterative Reconstruction in Image Space (IRIS) algorithm improves lesion-to-liver contrast at reduced radiation dosage while maintaining acceptable image noise in the detection of hepatocellular carcinomas (HCC) in thin (mean body mass index, 24 +/- 0.4 kg/m2) adults. SUBJECTS AND METHODS: A phantom simulating the liver with HCC was scanned at 50-400 mAs for 80, 100, 120 and 140-kVp. In addition, fifty patients with HCC who underwent multiphasic liver CT using dual-energy (80-kVp and 140-kVp) arterial scans were enrolled. Virtual 120-kVP scans (protocol A) and 80-kVp scans (protocol B) of the late arterial phase were reconstructed with filtered back-projection (FBP), while corresponding 80-kVp scans were reconstructed with IRIS (protocol C). Contrast-to-noise ratio (CNR) of HCCs and abdominal organs were assessed quantitatively, whereas lesion conspicuity, image noise, and overall image quality were assessed qualitatively. RESULTS: IRIS effectively reduced image noise, and yielded 29% higher CNR than the FBP at equivalent tube voltage and current in the phantom study. In the quantitative patient study, protocol C helped improve CNR by 51% and 172% than protocols A and B (p < 0.001), respectively, at equivalent radiation dosage. In the qualitative study, protocol C acquired the highest score for lesion conspicuity albeit with an inferior score to protocol A for overall image quality (p < 0.001). Mean effective dose was 2.63-mSv with protocol A and 1.12-mSv with protocols B and C. CONCLUSION: CT using the low-tube-voltage, intermediate-tube-current and IRIS help improve lesion-to-liver CNR of HCC in thin adults during the arterial phase at a lower radiation dose when compared with the standard technique using 120-kVp and FBP.