Serial computed tomography findings of Coronavirus disease 2019 (COVID-19) pneumonia treated with favipiravir and steroid therapy: report of 11 cases.

BACKGROUND: This study evaluated the time course of computed tomography (CT) findings of patients with COVID-19 pneumonia who required mechanical ventilation and were treated with favipiravir and steroid therapy. RESULTS: Eleven patients with severe COVID-19 pneumonia were included. CT findings assessed at the three time points showed that all patients had ground-glass opacities (GGO) and consolidation and mixed pattern at intubation. Consolidation and mixed pattern disappeared in most of the patients whereas GGO persisted in all patients at 1-month follow-up. In addition to GGO, a subpleural line and bronchus distortion and bronchial dilatation were frequent findings. The degree of resolution of GGO varied depending on each patient. The GGO score correlated significantly with the time from symptoms onset to initiation of steroid therapy (ρ = 0.707, p = 0.015). CONCLUSIONS: At 1-month follow-up after discharge, non-GGO lesions were absorbed almost completely, and GGO were a predominant CT manifestation. Starting steroid therapy earlier after onset of symptoms in severe COVID-19 pneumonia may reduce the extent of GGO at 1-month follow-up.

A case of esophagojejunal varices rupture after proximal gastrectomy with double-tract reconstruction.

BACKGROUND: The varices after proximal or total gastrectomy are uncommon because the supplying vessels are all divided. Emergent upper gastrointestinal endoscopy is the cornerstone of first-line management for the diagnosis and treatment of esophageal varices. However, there is no widely accepted standard strategy for esophagojejunal varices. We report a patient with esophagojejunal varices rupture 3 months after proximal gastrectomy treated with percutaneous transhepatic obliteration. CASE PRESENTATION: A 50-year-old man who had undergone proximal gastrectomy with double-tract reconstruction for esophagogastric junctional cancer 3 months before was admitted to the hospital due to gastrointestinal perforation. We performed emergency surgery and abdominal symptoms and inflammatory response improved postoperative. However, on POD3, he had eruptive bleeding at the just anal side of esophagojejunal anastomosis. Endoscopic clipping was unsuccessful because the mucosa was fragile and easily lacerated. Contrast-enhanced CT scan revealed the dilatation of the jejunal vein flowing into the ascending jejunal limb. Therefore, he was diagnosed as esophagojejunal varices rupture and percutaneous transhepatic obliteration (PTO) was tried for hemostasis. The portal and superior mesenteric veins were catheterized with the percutaneous transhepatic approach. Contrast agent injection into the jejunal branch demonstrated retrograde flow to the azygos vein through esophagojejunal varices. The microcatheter was inserted into the variceal blood supply branch and 10 mL of 5% ethanolamine oleate with iopamidol was injected. After obliteration therapy, the superior mesenteric venogram showed complete occlusion of the variceal supply branch. The patient was discharged from the hospital without any complications after 14 days. CONCLUSION: PTO can be effective for gastroesophageal varices rupture with a dilated jejunal vein of the ascending limb, few supplying vessels, and little ascites.

Surgical treatment of rectal cancer with a Retzius shunt: a case report.

BACKGROUND: A case of a short circuit (Retzius shunt) from the inferior mesenteric vein (IMV) to the inferior vena cava (IVC) without accompanying portal hypertension due to liver cirrhosis is rare. CASE PRESENTATION: An 83-year-old woman who was followed after surgery for thyroid and breast cancer was incidentally found to have rectal cancer on computed tomography (CT). Preoperative three-dimensional CT showed a venous malformation forming a short circuit (Retzius shunt) from the IMV to the IVC. Laparoscopic anterior rectal resection was performed. Operative findings included the Retzius vein crossing the abdominal aorta and the inferior mesenteric artery (IMA) to the IVC and a number of engorged vessels in the mesentery. The Retzius vein and IMA were clipped without major bleeding, and tumor-specific mesorectal excision was then performed. The patient's postoperative clinical course was good, and she was discharged without complications. CONCLUSIONS: Preoperative imaging enabled identification of an unexpected rare disease, thus reinforcing the importance of preoperative imaging.

Isolated unilateral proximal interruption of the pulmonary artery: findings of high-resolution computed tomography and three-dimensional volume rendering imaging of the pleura.

A unilateral proximal interruption of the pulmonary artery is a rare entity that is commonly associated with other congenital cardiovascular anomalies. However, less frequently, this condition may occur as an isolated finding, and some patients are completely asymptomatic. We report 2 cases of asymptomatic patients who had an isolated unilateral proximal interruption of the pulmonary artery. Herein, the radiological imaging findings are described with an emphasis on interlobular septal thickening of the affected lung demonstrated with high-resolution computed tomography. Three-dimensional volume rendering imaging clearly demonstrated reticular opacities on the surface of the affected side of the pleura.

[Efficacy of Combined Therapy(Drainage of the Bile Duct, High-Dose Hepatic Artery Infusion, and Radiation)for Hilar Cholangiocellularcarcinoma with Complete Portal Vein Obstruction].

We reported a case of hilar cholangiocellularcarcinoma with complete obstruction of the portal vein. The patient, who was a 65-year-old woman, suffered from fever and general fatigue as a result of acute cholangitis after insertion of a tube stent into the right bile duct. The main tumor was present on the right side of S1 and spread to both sides of the bile duct. S1 lobe was swollen and diffuse intrahepatic invasion was noted in the right lobe and S1. The portal vein was completely obstructed at the porta hepatis with a coronary vein-left renal vein shunt. We immediately administered a high-dose hepatic arterialinfusion( 5-FU 1 g×3 days: one day off 1 g×3 days)(HDHAI)to the right hepatic artery using a transient catheter insertion method. After 2 courses of HDHAI, the intrahepatic invasion decreased. However, after 4 courses of HDHAI(2 on the right side and 2 on the left side), the invasion on the left side of the IVC had increased. We then chose radiation therapy. Subsequently, transient cystic changes were observed; however, 4 months after radiation, the invasion on the left side of the IVC had regrown into the cardia. The patient suffered from vomiting as a result of the narrowing of the esophagus. We chose HDHAI and dilation of the esophagus using a balloon. Finally, the invasion on the left side of the IVC and S1 swelling decreased, and she could eat again. Thirteen months later, she remains an outpatient. We recommend HDHAI and radiation therapy to hilar cholangiocellularcarcinoma even if the portal vein is completely obstructed.

[Pre-Operative Treatment with Transcatheter Arterial Chemoembolization (TACE) and Hepatic Arterial Infusion (HAI) for Liver Metastasis from Gastric Cancer--A Case Report].

The patient was an 83-year-old man who underwent distal gastrectomy for gastric cancer (T3, N1, M0, P0, M0, stage ⅡB) at a different hospital from ours. A metastatic lesion was detected in the liver 5 months after gastrectomy. Although chemotherapy with S-1 or bi-weekly CPT-11 was administered for 6 months, the liver tumor increased in size. The patient was referred to our hospital for treatment of the liver metastasis. Abdominal-computed tomography (CT) and magnetic resonance imaging (MRI) revealed a solitary metastatic liver tumor (9 cm in diameter: S7/S6/S8) with a hypervascular tumor stain. Transcatheter arterial chemoembolization (TACE) using degradable starch microspheres (DSM) plus mitomycin C, and hepatic arterial infusion (HAI) using high-dose 5-fluorouracil (5-FU) (6,000 mg/week), were performed 54 days before curative resection of the liver (S6+S7+S8+S5b/c). Histological findings revealed metastatic adenocarcinoma with a tumor thrombus in the posterior branch of the portal vein. The patient was treated with 2 courses of adjuvant chemotherapy with paclitaxel. No recurrence was observed 8 months after hepatectomy. This case suggests that combined treatment with TACE/HAI as a multimodal treatment might be effective in the management of hypervascular liver metastasis from gastric cancer.

[A Case Report of Huge Liver Synchronous Metastases of Colon Cancer that Occurred after Right Liver Lobectomy].

We report a patient who experienced a weight loss, general fatigue, and appetite loss and had huge hepatic metastases of colon cancer after right lobectomy for hepatic stone. After 2 courses of treatment with high-dose hepatic arterial infusion of 5-FU (HDHAI; 5-FU 6 g/week), the appetite loss decreased, and low anterior resection was performed. Unfortunately, the other symptoms continued, and she received 5 additional courses of HDHAI during about 6 months. Finally, all of the symptoms disappeared, and she could receive systemic chemotherapy and HAI. Bone metastasis at vertebra TH 9 was observed about 9 months after radiotherapy, and local recurrence at the anastomosis site was observed at about 1 year 1 months after radiotherapy. Both the metastasis and local recurrence were well controlled. Although the lung metastases were growing slowly (number and size), the patient was well enough to go to the hospital on her own and her weight loss almost disappeared. If liver metastases were the most threatening factor of life, HDHAI may be effective for the improvement of symptoms.

[Five-year-survival in a case of large synchronous liver metastases from colon cancer treated with local (operation, HAI, RFA, and TAE) and systemic combined therapy].

A 58-year-old woman was suffering from abdominal pain due to large liver metastases(LM)and lung metastasis from sigmoid colon cancer. After laparoscopic sigmoidectomy, three 6 g/wk high dose hepatic arterial infusions(HDHAI)of5 - fluorouracil (5-FU) were administered and the tumor decreased in size. Unfortunately, the patient had an infectious pseudoaneurysm at the site of puncture. She was given a drainage and femoro-femoral(F-F)bypass. At last, a hepatectomy, radiofrequency ablation(RFA), and catheter insertion from gastroepiploic artery, were performed successfully. Subsequently, she received a half HDHAI and several systemic chemotherapy drugs. However, residual liver metastases developed thrice and we operated on all of them. Finally, when the hepatic arterial infusion(HAI)catheter became unavailable, we only continued the systemic therapy (Erbitux+FOLFIRI). However, inoperable residual liver metastases(maximum 13 cm in size)occurred. We chose to administer hepatic transarterial embolization(TAE)therapy 3 times. From the second time, we performed TAE from the right subphrenic artery and in the third time, we added 1-day HAI therapy. Finally, the tumor size decreased(maximum 9 cm). The patient is still an outpatient 5 years after the first HDHAI.

[A case of huge liver metastases from the colon cancer suffered from abdominal pain (an amount of LDH was beyond 4,000 IU/L)].

We report a case suffered from an abdominal pain with huge hepatic metastases from the colon cancer. After laparoscopic partial colectomy with a three-time treatment of high dose hepatic arterial infusion by 5-FU (HDHAI), the tumor was decreased in size. Unfortunately she had an infectious pseudoaneurysm at the site of puncture. She was given with a drainage and F-F bypass. She has at last successfully done hepatectomy, radiofrequency ablation (RFA), and insertion of catheter at the site of common hepatic artery from gastroepiploic artery. Then she received a half HDHAI and systemic chemotherapy of CPT-11. However, residual liver metastases happened twice, but we could have them operated all (9.3 months after and 20.5 months after from first operation). If the liver metastases were the most threatening factor of life, HDHAI and repeated hepatectomy maybe effective for prolongation of life.

[Efficacy of short-term high volume (6 g of 5-FU in a week) hepatic arterial infusion for synchronous diffuse liver metastases of sigmoid colon cancer with over 40 thousand ng/mL of CEA of ascites].

We report a case of patient who recovered from liver failure with synchronous diffuse liver metastases of sigmoid colon cancer by a short-term high volume (6 g of 5-FU in a week) hepatic arterial infusion (STHV-HAI). After four times of STHV-HAI, she had sigmoidectomy and bilateral oohorectomy and continued a weekly hepatic arterial infusion therapy until now. The case was a 75-year-old lady. She admitted of general fatigue. Serum bilirubin was about 2 mg/dL, GOT about 200 U/L and CEA over 40 thousand ng/mL. She started STHV-HAI next day of her admission. After 4-course, her liver function became normal and the amount of CEA level became about 1,000 ng/mL. We had the operation of sigmoidectomy and bilateral oohorectomy. After that, she received the HAI every week as an outpatient. The lowest level of CEA became at the 90 ng/mL. The liver metastases were also almost CR. STHV-HAI will be safe and effective to a patient of liver metastases with ascites and jaundice.

[A new method of short-term high volume (6 g of 5-FU in a week) intermittent hepatic arterial infusion using repeated transient catheter insertion].

We report a case of liver metastases, which had hepatectomy twice and a partial lung resection after sigmoidectomy with partial bladder resection for advanced sigmoid colon cancer. The patient could not be tolerated the systemic chemotherapy, and percutaneous implantation of a catheter also could not have done with subcutaneous reservoir for hepatic arterial infusion because of an anomaly of hepatic artery branched-out from super mesenteric artery. Therefore, we tried an intermittent hepatic arterial infusion using a transient insertion of catheter to control the liver metastases' growth. A total amount of 6 g of 5-FU was continuously injected in a week by one insertion of catheter at the hepatic artery taking one day rest at day 4. During the next 21 months, a total of 11 courses have been done. CEA and CA19-9 were changed from 15 ng/mL, 48 U/ mL to 18, 30, respectively. The patient was able to keep working except for the duration of this treatment. This procedure could be one of the hepatic arterial infusion options.

Magnetic resonance imaging-guided focused ultrasound ablation of uterine fibroids: early clinical experience.

PURPOSE: The aim of this study was to assess the feasibility and effectiveness of magnetic resonance (MRI)-guided focused ultrasound (MRIgFUS) ablation for uterine fibroids and to identify the candidates for this treatment. MATERIALS AND METHODS: A total of 48 patients with a symptomatic uterine fibroid underwent MRIgFUS. The percent ablation volume was calculated, and the patients' characteristics and the MR imaging features of the fibroids that might predict the effect of this treatment were assessed. Changes in the symptoms related to the uterine fibroid were assessed at 6 and 12 months. RESULTS: The planned target zone were successfully treated in 32 patients with bulk-related and menstrual symptoms but unsuccessfully treated in the remaining 16 patients. These 16 patients were obese or their uterine fibroid showed heterogeneous high signal intensity on T2-weighted images. The 32 successfully treated patients were followed up for 6 months. At the 6-month follow-up, bulk-related and menstrual symptoms were diminished in 60% and 51% of patients, respectively. Among them, 17 patients were followed up for 12 months, and 9 of them who showed alleviation of bulk-related symptoms at 6 months had further improvement. The mean percent ablation volume of those nine patients was 51%. In 5 (33%) of the 15 patients with alleviation of menstrual symptoms at 6 months, the symptoms became worse at 12 months. There was a significant difference in the mean percent ablation volume between patients with alleviation of menstrual symptoms and those without (54% vs. 37%; P = 0.03). CONCLUSION: MRIgFUS ablation is a safe, effective treatment for nonobese patients with symptomatic fibroids that show low signal intensity on T2-weighted images. Ablation of more than 50% of the fibroid volume may be needed with a short-term follow-up.

A case of hepatocellular carcinoma treated by MR-guided focused ultrasound ablation with respiratory gating.

Focused ultrasound surgery (FUS) is a method of noninvasive focal thermal ablation. Temperature-sensitive phase-difference magnetic resonance (MR) imaging allows monitoring of the focal point and measurement of tissue temperature elevation in real time, ensuring delivery of a therapeutic dose. A newly developed respiratory monitoring system enables us to track liver tumors, which move with respiration. We report our initial experience using MR-guided FUS with respiratory gating in successfully treating a hepatocellular carcinoma 15 mm in diameter.

Near-real-time feedback control system for liver thermal ablations based on self-referenced temperature imaging.

Our challenge was to design and implement a dedicated temperature imaging feedback control system to guide and assist in a thermal liver ablation procedure in a double-donut 0.5T open MR scanner. This system has near-real-time feedback capability based on a newly developed "self-referenced" temperature imaging method using "moving-slab" and complex-field-fitting techniques. Two phantom validation studies and one ex vivo experiment were performed to compare the newly developed self-referenced method with the conventional subtraction method and evaluate the ability of the feedback control system in the same MR scanner. The near-real-time feedback system was achieved by integrating the following primary functions: (1) imaging of the moving organ temperature; (2) on-line needle tip tracking; (3) automatic turn-on/off the heating devices; (4) a Windows operating system-based novel user-interfaces. In the first part of the validation studies, microwave heating was applied in an agar phantom using a fast spoiled gradient recalled echo in a steady state sequence. In the second part of the validation and ex vivo study, target visualization, treatment planning and monitoring, and temperature and thermal dose visualization with the graphical user interface of the thermal ablation software were demonstrated. Furthermore, MR imaging with the "self-referenced" temperature imaging method has the ability to localize the hot spot in the heated region and measure temperature elevation during the experiment. In conclusion, we have demonstrated an interactively controllable feedback control system that offers a new method for the guidance of liver thermal ablation procedures, as well as improving the ability to assist ablation procedures in an open MR scanner.

Determining the optimal timing for early arterial phase hepatic CT imaging by measuring abdominal aortic enhancement in variable contrast injection protocols.

OBJECTIVE: To find the optimal scan timing for early arterial phase hepatic CT with adequate arterial enhancement after the aortic contrast arrival. METHODS: Sixty patients were divided randomly into three groups, each of which received 2.0 mL/kg of the 300 mgI/mL contrast medium with an injection duration of 30 seconds (Group A, mean rate 3.6 mL/sec); of 25 seconds (B, 4.6 mL/sec); of 30 seconds (3.6 mL/sec) followed by a saline chaser (C). RESULTS: After the contrast arrival, aortic enhancement increased rapidly for 6-15 seconds (mean, 10 seconds) to the initial peak enhancement in all groups, and then, increased moderately to the maximum aortic enhancement over the following 19, 13, and 21 seconds, respectively. The mean maximum aortic enhancement in Group B (392 HU) and C (360 HU) were significantly higher than that in A (326 HU), respectively. The difference between the initial and maximum aortic enhancement was less than 50 HU. CONCLUSION: The optimal timing of the early arterial phase for hepatic CT arteriography is 10-15 seconds after the aortic arrival.

Using superparamagnetic iron oxide-enhanced MRI to differentiate metastatic hepatic tumors and nonsolid benign lesions.

OBJECTIVE: We evaluated the ability of superparamagnetic iron oxide (SPIO)-enhanced MRI to differentiate solid metastatic tumors and nonsolid benign lesions by clarifying the characteristic signal-intensity pattern of each lesion on SPIO-enhanced T2-weighted and heavily T1-weighted gradient-echo images. MATERIALS AND METHODS: SPIO-enhanced MRI was performed using a 1.5-T system in 33 consecutive patients without cirrhosis who had 81 focal hepatic lesions (42 cysts, 13 hemangiomas, 26 metastatic tumors). The relative signal intensity of lesions on SPIO-enhanced heavily T1- and T2-weighted gradient-echo images was classified into one of the following three categories: high intensity, isointensity, or low intensity relative to the surrounding liver parenchyma. The diagnostic accuracy for differentiating solid metastatic tumors from nonsolid benign lesions (cysts or hemangiomas) was determined. RESULTS: A combination of the relative signal intensity of the lesion on T2- and heavily T1-weighted gradient-echo images could be classified into the following five categories: high intensity and high intensity (category 1), high intensity and isointensity (category 2), high intensity and low intensity (category 3), isointensity and isointensity (category 4), and isointensity and low intensity (category 5). According to these categories, category 1 contained two hemangiomas, category 2 had 11 hemangiomas, category 3 had 25 metastatic tumors and two cysts, category 4 had three cysts, and category 5 had 37 cysts and one metastatic tumor. When a tumor with a relative signal intensity of categories 1 or 2 was considered to be a hemangioma (category 3 metastatic tumors and categories 4 and 5 cysts), diagnostic accuracy for characterizing such hepatic lesions was 96% (78/81). CONCLUSION: When evaluating metastatic liver tumors on SPIO-enhanced MRI, we recommend that heavily T1- and T2-weighted gradient-echo images be obtained with our parameters to exclude hemangiomas or cysts.

Evaluation of optimal timing of arterial phase imaging for the detection of hypervascular hepatocellular carcinoma by using triple arterial phase imaging with multidetector-row helical computed tomography.

PURPOSE: We evaluated the optimal timing of arterial phase imaging for detection of hypervascular hepatocellular carcinoma by using triple arterial phase imaging with multidetector-row helical computed tomography. MATERIALS AND METHODS: Forty-nine patients with 90 hypervascular hepatocellular carcinomas (3 to 50 mm in diameter; mean, 18.7 mm) underwent triple arterial phase imaging of the whole liver using a multidetector-row helical computed tomography. At 20 seconds, 30 seconds, and 40 seconds after intravenous administration of 100 mL of 300 mgI/mL of nonionic contrast medium at a rate of 4 mL/s, early, middle, and late arterial phase images were obtained serially during a single breath-hold with an interscan delay of 5 seconds. Detector-row configurations of 4 mm x 4, scan pitch of 5.5, and scan time of 5 seconds for each phase were used. Forty prospective reconstruction images of 5-mm thickness for each phase were obtained. The images from each phase were interpreted separately for detection of hypervascular hepatocellular carcinoma by 3 observers independently who were unaware of tumor burden in the liver. Sensitivity, positive predictive value, and area under the receiver operating characteristic curve values for each arterial phase were calculated and compared statistically. RESULTS: The mean sensitivity and positive predictive values for hypervascular hepatocellular carcinoma diagnosis of blind readers were 37% and 87% for the early arterial phase, 73% and 85% for the middle arterial phase, and 49% and 81% for the late arterial phase, respectively. The middle arterial phase imaging showed significantly superior sensitivity compared with the early and late arterial phase for detecting hepatocellular carcinoma (P < 0.05). Mean area under the receiver operating characteristic curve value of the middle arterial phase imaging (0.84) was significantly higher that that of the early (0.56) or late arterial phase (0.62; P < 0.05). CONCLUSION: If a single arterial phase is used for diagnosis of hypervascular hepatocellular carcinoma, the middle phase (delay time of 30 seconds) is optimal.

Detection of hypervascular hepatocellular carcinoma with dynamic magnetic resonance imaging with simultaneously obtained in-phase and opposed-phase echo images.

PURPOSE: The technique of double-phase echo chemical shift gradient-echo magnetic resonance (MR) imaging with the fast low-angle shot sequence (double-echo FLASH) provides in-phase and opposed-phase (double-phase) images simultaneously. The purpose of this study was to assess whether the dynamic study with a combination of in-phase and opposed-phase (double-phase) echo images improves the detectability of hypervascular hepatocellular carcinoma (HCC) compared with that with either in-phase or opposed-phase images alone. METHOD: Thirty-seven patients with 107 hypervascular HCCs who underwent the whole-liver double-phase echo dynamic MR imaging were enrolled in the study. Three radiologists blindly read in-phase images alone, opposed-phase images alone, and then double-phase images together. Sensitivity and positive predictive values as well as the areas below the alternative-free response receiver operating characteristic curve (Az values) for each imaging technique were calculated and compared statistically. RESULTS: The mean sensitivity, positive predictive values, and Az values for hypervascular HCCs were 51%, 77%, and 0.52 for in-phase imaging; 55%, 86%, and 0.58 for opposed-phase imaging; and 57%, 84%, and 0.63 for double-phase imaging, respectively. The mean sensitivity for opposed-phase imaging was significantly higher than that for in-phase imaging (P < 0.05), and the mean sensitivity for double-phase imaging was higher than that for in-phase imaging (P < 0.01). The mean Az value for the double-phase imaging was significantly higher than that for in-phase imaging (P < 0.01). CONCLUSION: Dynamic MR imaging with double-phase images was recommended for the detection of hypervascular HCC.

Detection of hepatocellular carcinoma: comparison of dynamic MR imaging with dynamic double arterial phase helical CT.

OBJECTIVE: Three-dimensional (3D) Fourier transformation-enhanced fast gradient-echo sequences with a special spectral inversion recovery pulse and fat suppression developed for abdominal imaging, including MR angiography, can show enhanced areas clearly. The purpose of this study was to evaluate the efficacy of dynamic MR imaging with the pulse sequences for the detection of hypervascular hepatocellular carcinoma by comparing it with that of dynamic helical CT with double arterial phase imaging. SUBJECTS AND METHODS: Fifty-three patients with 103 hypervascular hepatocellular carcinoma nodules who underwent both dynamic MR imaging with 3D Fourier transformation-enhanced fast gradient-echo sequences with a special spectral inversion recovery pulse and dynamic helical CT with double arterial phase imaging were enrolled in the study. For dynamic MR imaging, unenhanced, arterial, portal venous, and equilibrium phase images were obtained before and approximately 19, 60, and 120 sec, respectively, after injection of gadopentetate dimeglumine. Three observers independently interpreted the images obtained with each technique in a blinded manner and in random order. RESULTS: Mean sensitivity and positive predictive values of CT for hypervascular hepatocellular carcinoma (66% and 97%, respectively) were higher than those of MR imaging (63% and 96%, respectively), but there was no significant difference in detecting sensitivity among the observers (p < 0.05). CT and MR imaging were complementary, with some tumors undetected by CT but revealed on MR imaging. There was also no significant difference in A(z) values between CT (0.74) and MR imaging (0.71) (p < 0.05). CONCLUSION: Dynamic MR imaging with 3D Fourier transformation-enhanced fast gradient-echo sequences with a special spectral inversion recovery pulse is recommended to improve the detection of hypervascular hepatocellular carcinoma nodules in addition to the use of dynamic helical CT with double arterial phase imaging.

Detection of hypervascular hepatocellular carcinoma by dynamic magnetic resonance imaging with double-echo chemical shift in-phase and opposed-phase gradient echo technique: comparison with dynamic helical computed tomography imaging with double arterial phase.

PURPOSE: The technique of double-echo chemical shift gradient echo magnetic resonance imaging (MRI) with the fast low-angle shot (double-echo FLASH) sequence provides in-phase and opposed-phase images in a single breath hold. The purpose of this study was to evaluate the efficacy of dynamic MRI with double-echo FLASH imaging for the detection of hypervascular hepatocellular carcinoma by comparing it with dynamic helical computed tomography (CT) imaging with double arterial phase. MATERIALS AND METHODS: Twenty-nine patients with 67 hypervascular hepatocellular carcinoma nodules who underwent both dynamic MRI with double-echo FLASH imaging (repetition time/echo time/flip angle: 160/3.6, 7.0/80 degrees ) and dynamic helical CT imaging with double arterial phase were enrolled in the study. For dynamic MRI, precontrast, arterial, portal venous, and equilibrium phase images were obtained before and approximately 19, 60, and 120 seconds, respectively, after intravenous injection of 0.1 mmol/kg of gadopentetate dimeglumine at a rate of 2 ml/s. For dynamic CT imaging, quadraphase images, including early arterial, late arterial, portal venous, and equilibrium phases, were obtained serially approximately 20, 30, 70, and 180 seconds, respectively, after intravenous administration of 2 ml/kg of 300 mgI/ml of nonionic contrast medium at a rate of 5 ml/s. Three masked observers independently interpreted images obtained with each technique in random order, separately and without patient identifiers. Sensitivity and positive predictive values as well as the area below the alternative-free response receiver operating characteristic curve (Az) for each imaging technique were calculated and compared statistically. RESULTS: Mean sensitivity and positive predictive values of MRI for hypervascular hepatocellular carcinoma were 48% and 94%, respectively, and those of CT imaging were 47% and 91%, respectively. In 11 (38%) of the 29 patients, at least one observer judged dynamic MRI to be superior, whereas in 5 patients (17%), dynamic CT was judged to be superior. There was no significant difference in the sensitivity and positive predictive values between these techniques (p > 0.05). There was no significant difference either in mean Az values between CT (0.55) and MRI (0.57) (p = 0.61). CONCLUSION: Dynamic MRI with double-echo FLASH imaging can detect hypervascular hepatocellular carcinoma as well as dynamic helical CT imaging with double arterial phase.