A generalized ratiometric chemical exchange saturation transfer (CEST) MRI approach for mapping renal pH using iopamidol.

PURPOSE: To extend the pH detection range of iopamidol-based ratiometric chemical exchange saturation transfer (CEST) MRI at sub-high magnetic field and establish quantitative renal pH MRI. METHODS: Chemical exchange saturation transfer imaging was performed on iopamidol phantoms with pH of 5.5 to 8.0 and in vivo on rat kidneys (n = 5) during iopamidol administration at a 4.7 T. Iopamidol CEST effects were described using a multipool Lorentzian model. A generalized ratiometric analysis was conducted by ratioing resolved iopamidol CEST effects at 4.3 and 5.5 ppm obtained under 1.0 and 2.0 µT, respectively. The pH detection range was established for both the standard ratiometric analysis and the proposed resolved approach. Renal pH was mapped in vivo with regional pH assessed by one-way analysis of variance. RESULTS: Good-fitting performance was observed in multipool Lorentzian resolving of CEST effects (R2 s > 0.99). The proposed approach extends the in vitro pH detection range to 5.5 to 7.5 at 4.7 T. In vivo renal pH was measured to be 7.0 ± 0.1, 6.8 ± 0.1, and 6.5 ± 0.2 for cortex, medulla and calyx, respectively (P < 0.05). CONCLUSIONS: The proposed ratiometric approach extended the iopamidol pH detection range, enabling the renal pH mapping in vivo, which is promising for pH imaging studies at sub-high or low fields with potential clinical applicability. Magn Reson Med 79:1553-1558, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Triphasic contrast enhanced CT simulation with bolus tracking for pancreas SBRT target delineation.

PURPOSE: Bolus-tracked multiphasic contrast computed tomography (CT) is often used in diagnostic radiology to enhance the visibility of pancreas tumors, but is uncommon in radiation therapy pancreas CT simulation, and its impact on gross tumor volume (GTV) delineation is unknown. This study evaluates the lesion conspicuity and consistency of pancreas stereotactic body radiation therapy (SBRT) GTVs contoured in the different contrast phases of triphasic CT simulation scans. METHODS AND MATERIALS: Triphasic, bolus-tracked planning CT simulation scans of 10 consecutive pancreas SBRT patients were acquired, yielding images of the pancreas during the late arterial (LA), portal venous (PV), and either the early arterial or delayed phase. GTVs were contoured on each phase by a gastrointestinal-specialized radiation oncologist and reviewed by a fellowship-trained abdominal radiologist who specializes in pancreatic imaging. The volumes of the registered GTVs, their overlap ratio, and the 3-dimensional margin expansions necessary for each GTV to fully encompass GTVs from the other phases were calculated. The contrast difference between tumor and normal pancreas was measured, and 2 radiation oncologists rank-ordered the phases according to their value for the lesion-contouring task. RESULTS: Tumor-to-pancreas enhancement was on average much larger for the LA and PV than the delayed phase or early arterial phases; the LA and PV phases were also consistently preferred by the radiation oncologists. Enhancement differences among the phases resulted in highly variable GTV volumes with no observed trends. Overlap ratios ranged from 18% to 75% across all 3 phases, improving to 43% to 91% when considering only the preferred LA and PV phases. GTV expansions necessary to encompass all GTVs ranged from 0.3 to 1.8 cm for all 3 phases, improving slightly to 0.1 to 1.4 cm when considering just the LA and PV phases. CONCLUSIONS: For pancreas SBRT, we recommend combining the GTVs from a multiphasic CT simulation with bolus-tracking, including, at a minimum, a Boolean "OR" of the LA and PV phases.

Computed tomography features of benign and malignant solid thyroid nodules.

BACKGROUND: No previous study has investigated computed tomography (CT) features of benign and malignant solid thyroid nodules using detailed CT features and histopathological results. PURPOSE: To assess CT features of benign and malignant solid thyroid nodules in patients who underwent thyroid surgery. MATERIAL AND METHODS: From January to April 2014, 151 consecutive patients underwent neck CT before thyroid surgery. In each case, neck CT was retrospectively examined by a single radiologist. We evaluated the diagnostic accuracy of specific CT features for differentiating malignant from benign thyroid nodules using histopathological results as a reference standard. RESULTS: Of 173 thyroid nodules in 142 patients, 162 (mean diameter, 12.8 ± 10.3 mm; range, 5.0-93.7 mm) were visualized on neck CT. Of 162 nodules in 133 patients, 116 were malignant and 46 were benign as confirmed by histopathology. A multivariate logistic regression analysis showed a significant difference between malignant and benign thyroid nodules in the degree and pattern of nodular enhancement, but there were no significant differences in other CT features. In particular, thyroid nodules with exophytic configuration, irregular margin, taller-than-wide shape, punctate calcifications, or homogeneously decreased enhancement showed a high malignancy rate. CONCLUSION: The study demonstrated that the degree and pattern of nodular enhancement are helpful CT features for differentiating malignant from benign solid thyroid nodules.

Factors related to thrombosis of gastric varix during balloon-occluded retrograde transvenous obliteration.

BACKGROUND: Balloon-occluded retrograde transvenous obliteration (B-RTO) has become known as an effective treatment for gastric varices with a gastrorenal shunt. However, the appropriate duration to maintain inflation of the catheter balloon for sufficient thrombosis has been unknown. PURPOSE: To evaluate retrospectively the factors related to the development of thrombus in gastric varices by evaluating the necessity of the addition of a sclerosing agent on the second day in overnight B-RTO. MATERIAL AND METHODS: Sixty-five patients who underwent B-RTO for gastric varices with a gastrorenal shunt were studied. The B-RTO catheter was retained overnight in all patients. Incidence of and factors influencing the necessity of additional injections of a sclerosing agent on the second day were investigated. RESULTS: In all 65 patients (100%), B-RTO was technically successful and in 61 patients (93.8%) complete thrombosis of the gastric varices was achieved. In 46 of the 65 patients (70.8%), the sclerosing agent was added on the second day. Higher Child-Pugh score, in particular, lower serum albumin level, and higher prothrombin time-international normalized ratio (PT-INR) were significantly associated with the need for the addition of the sclerosing agent on the second day. Optimal cut-off values for the serum albumin level and PT-INR were 3.6 g/dL and 1.13, respectively. CONCLUSION: Liver function might influence the development of thrombosis of gastric varices in B-RTO. Serum albumin and PT-INR levels would provide information for deciding on the duration of retention of the B-RTO catheter to obtain sufficient therapeutic effectiveness.

Balloon-occluded retrograde transvenous obliteration of gastric varix via the pericardiacophrenic vein.

We encountered a case of gastric varix without a gastrorenal shunt that drained through the left pericardiacophrenic vein, which entered the left brachiocephalic vein. For this case we successfully performed balloon occluded retrograde transvenous obliteration, in which sclerotic agents were infused via the left pericardiacophrenic vein approached from the left subclavian vein.

Successful embolization therapy for bleeding from jejunal varices after choledochojejunostomy: report of a case.

We report a case of successful embolization of jejunal varices that were the cause of massive gastrointestinal bleeding from a choledochojejunostomy site, resulting from obstruction of the extrahepatic portal vein. A 42-year-old man who had undergone choledochojejunostomy for intrahepatic and choledochal stones was readmitted after he started passing massive dark bloody stools. Gastrointestinal endoscopic examination and angiography could not identify the source of bleeding. Percutaneous transhepatic portography showed obstruction of the right branches of the portal vein. The formation of jejunal varices at the site of choledochojejunostomy was revealed by portography and by cholangioscopy, suggesting the varices as the cause of massive bleeding. Bleeding could not be controlled long-term by cholangioscopic sclerosing therapy. We finally stopped the bleeding by embolizing a jejunal vein to the afferent loop.

Iopamidol enema treatment for meconium obstruction of prematurity in extremely low-birth weight infants: a safe and effective method.

BACKGROUND/PURPOSE: Meconium obstruction of prematurity (MO) often occurs in extremely low-birth weight (ELBW) infants, and its treatment is quite a challenge for neonatologists. We attempted to establish a method of primary treatment for MO of prematurity in ELBW infants. METHODS: An iopamidol enema with 50 cm H(2)O static pressure was performed as the primary treatment. This procedure is safe and effective and we recommend this as the first treatment for MO in ELBW infants. RESULTS: The procedure was performed 50 times in 23 infants and no complications occurred. Out of 23 patients, 20 (88%) improved, but the other 3 did not. In the failure group, the procedure was performed on a significantly later date and the mortality rate was higher (12.5 vs. 67%). CONCLUSIONS: This procedure is safe and effective. We recommend this as the first treatment for MO in ELBW infants.

Usefulness of cone-beam volume CT with flat panel detectors in conjunction with catheter angiography for transcatheter arterial embolization.

PURPOSE: To assess the usefulness of cone-beam volume computed tomography (CT) (cone-beam CT) with use of flat panel detectors of the direct conversion type in conjunction with conventional digital subtraction angiography (DSA) in the diagnosis and treatment of patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: Forty-nine consecutive patients (52 suspicious lesions) were prospectively examined. All patients underwent intraarterial rotational angiography with a flat panel detector system, and the cone-beam CT scans were reconstructed from the volume data set. The authors evaluated the diagnostic quality of cone-beam CT for the transcatheter arterial chemoembolization (TACE) procedure. RESULTS: The diagnostic quality of conventional DSA plus cone-beam CT with regard to tumor staining was superior to that of DSA alone. Cone-beam CT showed tumor staining in five lesions that were difficult to diagnose with confidence on the basis of the DSA findings alone. The extent of contrast medium perfusion was sufficiently visualized on all cone-beam CT scans at the tip of the catheter positioned in either the segmental or subsegmental hepatic arteries. In 42 of the 52 lesions (81%), cone-beam CT provided additional useful information for therapeutic decision making or TACE compared with DSA. CONCLUSIONS: Intraarterial cone-beam CT with a flat panel detector can provide clinically acceptable image quality in the assessment of HCC, thereby improving the detection of tumor staining due to HCC and the visualization of the extent of contrast medium perfusion.

Endovascular obliteration of bleeding duodenal varices in patients with liver cirrhosis.

The purpose of this paper is to describe our experience with endovascular obliteration of duodenal varices in patients with liver cirrhosis and portal hypertension. Balloon-occluded transvenous retrograde and percutaneous transhepatic anterograde embolizations were performed for duodenal varices in five patients with liver cirrhosis, portal hypertension, and decreased liver function. All patients had undergone previous endoscopic treatments that failed to stop bleeding and were poor surgical candidates. Temporary balloon occlusion catheters were used to achieve accumulation of an ethanolamine oleate-iopamidol mixture inside the varices. Elimination of the varices was successful in all patients. Retrograde transvenous obliteration via efferent veins to the inferior vena cava was enough to achieve adequate sclerosant accumulation in three patients. A combined anterograde-retrograde embolization was used in one patient with balloon occlusion of afferent and efferent veins. Transhepatic embolization through the afferent vein was performed in one patient under balloon occlusion of both efferent and afferent veins. There was complete variceal thrombosis and no bleeding was observed at follow-up. No major complications were recorded. Endovascular obliteration of duodenal varices is a feasible and safe alternative procedure for managing patients with portal hypertension and hemorrhage from this source.

Lumbar zygapophyseal joint injections in patients with chronic lower back pain.

BACKGROUND: This study was designed to assess the diagnostic value and clinical benefits of lumbar zygapophyseal joint injections in patients with chronic lower back pain. METHODS: Two hundred and seventy-seven patients (136 males and 141 females, aged 15-82 years) with chronic lower back pain were enrolled in the trial and met the following criteria: pain for more than 1 year; no root signs; and no history of back surgery. Under fluoroscope, a 0.8-1.5 mL mixture of lidocaine, betamethasone dipropionate and iopamidol (1:1:0.5) was injected into each joint after intra-articular localization of the needle tip was confirmed. A questionnaire with a pain scale was administered immediately or the day after injection, and then after 1, 3, 6 and 12 weeks. Partial arthrograms were reviewed by a radiologist. RESULTS: Four hundred and forty-nine joint injections were performed in 277 patients (L3-4, n = 76; L4-5, n = 272; L5-S1, n = 101). Bilateral injections were performed in 117 patients (42.2%). The study group comprised 204 patients (73.6%) with an excellent or good response, whereas the control group comprised the remaining 73 patients (26.4%). The rates of good response in the study group were 72.1% (147/204) after 3 weeks, 40.7% (83/204) after 6 weeks, and 31.4% (64/204) after 12 weeks. Partial arthrograms revealed 25 patients (9.0%) with synovial cysts (L3-4, n = 3; L4-5, n = 14; L5-S1, n = 8); 23 of these patients (92.0%) had a good response to the injections. Five of the 6 patients with spondylolysis (83.3%), having abnormal communication between the injected and contiguous joint, had a good response to the injections. The abovementioned, abnormal partial-arthrogram findings correlated significantly with the rate of good response to the injections. Although 3 patients had contrast medium extravasated into the epidural space during injection, none of the 277 patients had deteriorating lower back pain after the injections. CONCLUSION: Lumbar zygapophyseal joint injections, as a useful diagnostic tool for facet joint syndrome, could also have useful palliative effects in the management of chronic lower back pain.

Transvenous sclerotherapy for huge oesophagogastric varices using open injection sclerotherapy.

BACKGROUND: The optimum procedure for long-term management of oesophagogastric varices when endoscopic sclerotherapy or ligation fails is yet to be established. This report describes a new procedure for treating huge oesophagogastric varices by open injection sclerotherapy. METHODS: Twenty-three patients with huge oesophagogastric varices underwent laparotomy and devascularization of the upper stomach with splenectomy. The left gastric vein was catheterized for repeated injection of 5 per cent ethanolamine oleate during the postoperative period. RESULTS: In all patients, the varices were eradicated after a mean of 3 sessions of sclerotherapy. There were no deaths or major complications during the mean follow-up period of 41 months. Small recurring varices in two patients were treated successfully by endoscopic sclerotherapy and interventional radiology. CONCLUSION: Open injection sclerotherapy is an effective and safe procedure for the treatment of huge oesophagogastric varices.

A novel therapeutic approach for rectal varices: a case report of rectal varices treated with double balloon-occluded embolotherapy.

We present a patient with continuous melena, diagnosed as rectal varices bleeding. She had a history of esophageal varices, which was treated by endoscopic ligation therapy. Eight years after the treatment of esophageal varices, the continuous melena began. Colonoscopic examination showed that the melena was caused by rectal varices, which were so severe that they could not be treated by either endoscopic sclerotherapy or surgical devascularization. Taking into considering the overall risk of treating rectal varices, we chose the approach of double balloon-occluded embolotherapy (DBOE) with 5% ethanolamine oleate with iopamodol as a liquid embolic material. DBOE is one of the interventional radiology techniques (Morita et al., Acta Hepatol Jpn 1994;35:109-120), but in this case was a completely new and novel clinical procedure for rectal varices. After the DBOE therapy, the condition of rectal varices was markedly improved. Thus, DBOE might be a new tool for treating inoperable rectal varices.

Balloon-occluded retrograde transvenous obliteration for gastric varices with gastrorenal or gastrocaval collaterals.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of balloon-occluded retrograde transvenous obliteration for gastric varices with gastrorenal or gastrocaval collaterals. SUBJECTS AND METHODS: Thirty patients who had gastric varices with gastrorenal or gastrocaval collaterals underwent balloon-occluded retrograde transvenous obliteration. A 5-French balloon catheter was inserted in the gastrorenal collateral, gastrocaval collateral, or both, and a 5% solution of ethanolamine oleate iopamidole that contained equal amounts of ethanolamine oleate and iopamidole 300 was injected into the gastric varices. One day, 1 week, and 1 month after balloon-occluded retrograde transvenous obliteration, hepatic and renal function tests (total bilirubin, transaminase, blood ammonia, serum creatinine, and blood urea nitrogen) were done. To evaluate therapeutic efficacy, we observed the site with endoscopy every 2 weeks and obtained enhanced CT scans every month. The observation time ranged from 10 to 30 months. RESULTS: After balloon-occluded retrograde transvenous obliteration, gastric varices disappeared completely in all 30 cases in 4-16 weeks (mean, 10 weeks). Recurrence of gastric varices was observed in three cases (10%), which were treated with repeated balloon-occluded retrograde transvenous obliteration. Esophageal varices were aggravated in three patients (10%), who underwent successful endoscopic injection sclerotherapy. Complications of balloon-occluded retrograde transvenous obliteration were fever and hemoglobinuria, which disappeared in about 5 days. We observed no significant hepatic and renal functional damage. CONCLUSION: Balloon-occluded retrograde transvenous obliteration offers good control of gastric varices with gastrorenal or gastrocaval collaterals, even if hepatic function is poor.

Percutaneous penile venoablation for treatment of impotence.

Percutaneous penile venoablation with sclerosing agents and coils was performed in 58 patients. Of 104 ablations attempted, 44 of 51 (86%) transpenile, and 46 of 53 (86.7%) retrograde interventions were technically successful. In 40 patients (69%) erectile function improved (intercourse was possible in 21 without additional measures). Initially improved erectile function deteriorated in 24 patients during follow-up (in an average of 6 months); in 15 of these, intercourse was still possible with injection of vasoactive drugs. In 7 patients, repeat venoablation improved erectile function again. Hot contrast medium was slightly superior to sodium morrhuate as a sclerosing agent. In successfully treated patients, the average decrease in venous leakage was 30 ml/min vs 13 ml/min in treatment failures, with considerable overlap between both groups. Only minor complications were observed. We conclude that percutaneous penile venoablation is technically feasible, and safe. Whether the procedure will have a definite role in the treatment of venogenic impotence, however, still has to be determined.

Intraocular radiation blocking.

Iodine-based liquid radiographic contrast agents were placed in normal and tumor-bearing (Greene strain) rabbit eyes to evaluate their ability to block iodine-125 radiation. This experiment required the procedures of tumor implantation, vitrectomy, air-fluid exchange, and 125I plaque and thermoluminescent dosimetry (TLD) chip implantation. The authors quantified the amount of radiation attenuation provided by intraocularly placed contrast agents with in vivo dosimetry. After intraocular insertion of a blocking agent or sham blocker (saline) insertion, episcleral 125I plaques were placed across the eye from episcleral TLD dosimeters. This showed that radiation attenuation occurred after blocker insertion compared with the saline controls. Then computed tomographic imaging techniques were used to describe the relatively rapid transit time of the aqueous-based iohexol compared with the slow transit time of the oil-like iophendylate. Lastly, seven nontumor-bearing eyes were primarily examined for blocking agent-related ocular toxicity. Although it was noted that iophendylate induced intraocular inflammation and retinal degeneration, all iohexol-treated eyes were similar to the control eyes at 7 and 31 days of follow-up. Although our study suggests that intraocular radiopaque materials can be used to shield normal ocular structures during 125I plaque irradiation, a mechanism to keep these materials from exiting the eye must be devised before clinical application.