Yon Kwon Ihn

The role of diffusion-weighted imaging and the apparent diffusion coefficient (ADC) values for breast tumors.

Objective We wanted to evaluate the role of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) for detecting breast tumors, as compared with the T1- and T2-weighted images. Materials and Methods Forty-one female patients underwent breast MRI, and this included the T1-, T2-, DWI and dynamic contrast-enhanced images. Sixty-five enhancing lesions were detected on the dynamic contrast-enhanced images and we used this as a reference image for detecting tumor. Fifty-six breast lesions were detected on DWI and the histological diagnoses were as follows: 43 invasive ductal carcinomas, one mucinous carcinoma, one mixed infiltrative and mucinous carcinoma, seven ductal carcinomas in situ (DCIS), and four benign tumors. First, we compared the detectability of breast lesions on DWI with that of the T1- and T2-weighted images. We then compared the ADCs of the malignant and benign breast lesions to the ADCs of the normal fibroglandular tissue. Results Fifty-six lesions were detected via DWI (detectability of 86.2%). The detectabilities of breast lesions on the T1- and T2-weighted imaging were 61.5% (40/65) and 75.4% (49/65), respectively. The mean ADCs of the invasive ductal carcinoma (0.89 ± 0.18 × 10-3mm2/second) and DCIS (1.17 ± 0.18 × 10-3mm2/second) are significantly lower than those of the benign lesions (1.41 ± 0.56 × 10-3mm2/second) and the normal fibroglandular tissue (1.51 ± 0.29 × 10-3mm2/second). Conclusion DWI has a high sensitivity for detecting breast tumors, and especially for detecting malignant breast tumors. DWI was an effective imaging technique for detecting breast lesions, as compared to using the T1- and T2-weighted images.

Acute bilateral basal ganglia lesions in diabetic uraemia: diffusion-weighted MRI.

MethodsWe studied four patients with diabetes mellitus and chronic renal failure who developed sudden choreic movement disorders. The clinical manifestations, laboratory findings, MR imaging findings, and clinical outcome in each patient were evaluated.ResultsAll four patients had long-term diabetes mellitus and severe azotaemia. Brain MR findings consisted of bilateral symmetric basal ganglia lesions, with decreased signal intensity on T1-weighted images and increased signal intensity on T2-weighted images. All three patients who underwent diffusion-weighted MR imaging (DWI) showed signal intensities similar to those of the surroundings in regions corresponding to increased signal intensity on T2-weighted images, with slightly increased apparent diffusion coefficient (ADC) values. Two of the patients showed small focal areas of restricted diffusion within the basal ganglia lesions. After haemodialysis, follow-up MR imaging in all patients demonstrated that the basal ganglia lesions had regressed markedly, with some residual changes. The movement disorders also improved in all patients.ConclusionA syndrome associated with acute bilateral basal ganglia lesions in diabetic uraemic patients is rare, with reversible changes demonstrated by clinical and imaging findings. DWI showed that the bilateral basal ganglia lesions in this syndrome were primarily vasogenic in origin, although there were small foci of cytotoxic oedema within the lesions.

Reconstructive treatment of ruptured blood blister-like aneurysms with stent and coil.

BACKGROUND Controversy remains about the optimal treatment for blood blister--like aneurysms (BBAs). OBJECTIVE To evaluate clinical and angiographic outcomes after reconstructive treatment for BBA with stent and coil. METHODS Thirty-four patients (6 men, 28 women; mean age, 47.3 years) with ruptured BBAs underwent reconstructive treatment with stent and coil. Posttreatment courses and outcomes were retrospectively evaluated. RESULTS Initial treatments were ≥ 2 overlapping stents with or without coiling (n = 28) and single stent with coiling (n = 6). Three BBAs rebled on days 9, 11, and 15 after treatment, resulting in 1 death. Except for 3 patients who died early, 31 patients were followed up for 7 to 80 months (median, 32 months). One patient recovered completely but died of complications of systemic lupus erythematosus at 25 months. Of the remaining 30 patients, 25 had favorable outcomes (modified Rankin scale, 0-2) and 5 had unfavorable outcomes. Angiographic follow-up was available in the 32 BBAs. Eight (25.0%) recurred, all within 5 weeks. In the multiple stents group (n = 26), 22 BBAs showed improvement or complete healing, but 4 (15.4%, 2 rebleedings) had recurrence. In the single stent with coiling group (n = 6), 2 BBAs were stable but 4 (66.7%, 1 rebleeding) had recurrence. Single stent with coiling and Hunt and Hess grade ≥ 4 were 2 independent risk factors for recurrence (P < .05). CONCLUSION Reconstructive treatment with stent and coil appears a viable option for BBAs. Single stent with coiling and Hunt and Hess grade ≥ 4 were 2 independent risk factors for recurrence. Follow-up angiography should be considered mandatory soon after treatment. ABBREVIATIONS BBA, blood blister--like aneurysmICA, internal carotid arterymRS, modified Rankin ScaleSAH, subarachnoid hemorrhage.

Transvenous Embolization of Cavernous and Paracavernous Dural Arteriovenous Fistula through the Facial Vein: Report of 12 Cases

Purpose The aim of this study was to evaluate the feasibility and safety of the transfacial venous embolization of cavernous or paracavernous dural arteriovenous fistula (DAVF) in which approach via inferior petrosal sinus (IPS) was not feasible. Materials and Methods We identified the cases of transfacial venous embolization of cavernous sinus (CS) or adjacent dural sinuses from the neurointerventional database of three hospitals. The causes and clinical and angiographic outcomes of transfacial venous embolization were retrospectively evaluated. Results Twelve patients with CS (n = 11) or lesser wing of sphenoid sinus (LWSS, n = 1) DAVF were attempted to treat by transvenous embolization via ipsilateral (n = 10) or contralateral (n = 2) facial vein. Trans-IPS access to the target lesion was impossible due to chronic occlusion (n = 11) or acute angulation adjacent the target lesion (n = 1). In all twelve cases, it was possible to navigate through facial vein, angular vein, superior ophthalmic vein, and then CS. It was also possible to further navigation to contralateral CS through intercavernous sinus in two cases, and laterally into LWSS in one case. Post-treatment control angiography revealed complete occlusion of the DAVF in eleven cases and partial occlusion in one patient, resulting in complete resolution of presenting symptom in eight and gradually clinical improvement in four patients. There was no treatment-related complication during or after the procedure. Conclusion In the cavernous or paracavernous DAVF in which trans-IPS approach is not feasible, the facial vein seems to be safe and effective alternative route for transvenous embolization.

The Efficacy of Endovascular Treatment of Ruptured Blood Blister-Like Aneurysms Using Stent-Assisted Coil Embolization

We report our experience with endovascular treatment and follow-up results of a ruptured blood blister-like aneurysm (BBA) in the supraclinoid internal carotid artery. We performed a retrospective review of ruptured blood blister-like aneurysm patients over a 30-month period. Seven patients (men/women, 2/5; mean age, 45.6 years) with ruptured BBAs were included from two different institutions. The angiographic findings, treatment strategies, and the clinical (modified Rankin Scale) and angiographic outcomes were retrospectively analyzed. All seven BBAs were located in the supraclinoid internal carotid artery. Four of them were ≥ 3 mm in largest diameter. Primary stent-assisted coiling was performed in six out of seven patients, and double stenting was done in one patient. In four patients, the coiling was augmented by overlapping stent insertion. Two patients experienced early re-hemorrhage, including one major fatal SAH. Complementary treatment was required in two patients, including coil embolization and covered-stent placement, respectively. Six of the seven BBAs showed complete or progressive occlusion at the time of late angiographic follow-up. The clinical midterm outcome was good (mRS scores, 0–1) in five patients. Stent-assisted coiling of a ruptured BBA is technically challenging but can be done with good midterm results. However, as early regrowth/re-rupture remains a problem, repeated, short-term angiographic follow-up is required so that additional treatment can be performed as needed.

Diffuse Hepatic Hemangiomatosis without Extrahepatic Involvement in an Adult Patient

We report an extremely rare case of a diffuse hepatic hemangiomatosis without extrahepatic involvement in an adult. The imaging findings of this tumor were similar to those of a hepatic hemangioma and included contrast enhancement with a centripetal filling pattern of the entire hepatic tumor on the delayed phase of a dynamic CT and inhomogeneous diffuse uptake of the entire tumor on blood-pool images obtained five hours later on a 99mTc-labeled red blood cell scan. Despite its rarity, diffuse hepatic hemangiomatosis can be suggested in adult patients with diffusely involved hepatic tumors showing the radiological findings of a hepatic hemangioma.

Patient Radiation Exposure During Diagnostic and Therapeutic Procedures for Intracranial Aneurysms: A Multicenter Study

Purpose To assess patient radiation doses during cerebral angiography and embolization of intracranial aneurysms across multi-centers and propose a diagnostic reference level (DRL). Materials and Methods We studied a sample of 490 diagnostic and 371 therapeutic procedures for intracranial aneurysms, which were performed at 23 hospitals in Korea in 2015. Parameters including dose-area product (DAP), cumulative air kerma (CAK), fluoroscopic time and total angiographic image frames were obtained and analyzed. Results Total mean DAP, CAK, fluoroscopy time, and total angiographic image frames were 106.2 ± 66.4 Gy-cm2, 697.1 ± 473.7 mGy, 9.7 ± 6.5 minutes, 241.5 ± 116.6 frames for diagnostic procedures, 218.8 ± 164.3 Gy-cm2, 3365.7 ± 2205.8 mGy, 51.5 ± 31.1 minutes, 443.5 ± 270.7 frames for therapeutic procedures, respectively. For diagnostic procedure, the third quartiles for DRLs were 144.2 Gy-cm2 for DAP, 921.1 mGy for CAK, 12.2 minutes for fluoroscopy times and 286.5 for number of image frames, respectively. For therapeutic procedures, the third quartiles for DRLs were 271.0 Gy-cm2 for DAP, 4471.3 mGy for CAK, 64.7 minutes for fluoroscopy times and 567.3 for number of image frames, respectively. On average, rotational angiography was used 1.5 ± 0.7 times/session (range, 0-4; n=490) for diagnostic procedures and 1.6 ± 1.2 times/session (range, 0-4; n=368) for therapeutic procedures, respectively. Conclusion Radiation dose as measured by DAP, fluoroscopy time and image frames were lower in our patients compared to another study regarding cerebral angiography, and DAP was lower with fewer angiographic image frames for therapeutic procedures. Proposed DRLs can be used for quality assurance and patient safety in diagnostic and therapeutic procedures.

Patient Radiation Dose in Diagnostic and Interventional Procedures for Intracranial Aneurysms: Experience at a Single Center

Objective To assess patient radiation doses during cerebral angiography and embolization of intracranial aneurysms in a large sample size from a single center. Materials and Methods We studied a sample of 439 diagnostic and 149 therapeutic procedures for intracranial aneurysms in 480 patients (331 females, 149 males; median age, 57 years; range, 21-88 years), which were performed in 2012 with a biplane unit. Parameters including fluoroscopic time, dose-area product (DAP), and total angiographic image frames were obtained and analyzed. Results Mean fluoroscopic time, total mean DAP, and total image frames were 12.6 minutes, 136.6 ± 44.8 Gy-cm2, and 251 ± 49 frames for diagnostic procedures, 52.9 minutes, 226.0 ± 129.2 Gy-cm2, and 241 frames for therapeutic procedures, and 52.2 minutes, 334.5 ± 184.6 Gy-cm2, and 408 frames for when both procedures were performed during the same session. The third quartiles for diagnostic reference levels (DRLs) were 14.0, 61.1, and 66.1 minutes for fluoroscopy time, 154.2, 272.8, and 393.8 Gy-cm2 for DAP, and 272, 276, and 535 for numbers of image frames in diagnostic, therapeutic, and both procedures in the same session, respectively. The proportions of fluoroscopy in DAP for the procedures were 11.4%, 50.5%, and 36.1%, respectively, for the three groups. The mean DAP for each 3-dimensional rotational angiographic acquisition was 19.2 ± 3.2 Gy-cm2. On average, rotational angiography was used 1.4 ± 0.6 times/session (range, 1-4; n = 580). Conclusion Radiation dose in our study as measured by DAP, fluoroscopy time and image frames did not differ significantly from other reported DRL studies for cerebral angiography, and DAP was lower with fewer angiographic image frames for embolization. A national registry of radiation-dose data is a necessary next step to refine the dose reference level.

Antegrade recanalization of parent artery after internal trapping of ruptured vertebral artery dissecting aneurysm.

We report a patient with a ruptured vertebral artery (VA) dissecting aneurysm that was treated by internal trapping of the aneurysm and parent artery using detachable coils with subsequent antegrade recanalization of occluded vertebral artery during the follow-up period. A 38-year-old man was admitted with a ruptured right VA dissecting aneurysm just distal to origin of right posterior inferior cerebellar artery. The dissected segment of the VA was occluded by coil embolization. The 14 months follow-up angiography showed that dissected aneurysm was completely occluded, but the parent artery was recanalized in an antegrade fashion. Based on this unique case, the authors suggest that careful angiographic follow-up of dissecting aneurysm is required, even in patients successfully treated with endovascular occlusion of the affected artery and aneurysm.

Dural Arteriovenous Fistula Involving an Isolated Sinus Treated Using Transarterial Onyx Embolization

The authors present a case of isolated dural arteriovenous fistula (DAVF) in the transverse sinus, which developed six years after microvascular decompression caused by hemifacial spasm via suboccipital craniectomy. The lesion was successfully treated by transarterial embolization using Onyx. We reviewed the related radiologic and therapeutic features of DAVF involving an isolated sinus and described the feasibility of the use of Onyx.