Monitoring Radiation Doses during Diagnostic and Therapeutic Neurointerventional Procedures: Multicenter Study for Establishment of Reference Levels / 신경중재치료의학

Purpose@#To assess patient radiation doses during diagnostic and therapeutic neurointerventional procedures from multiple centers and propose dose reference level (RL). @*Materials and Methods@#Consecutive neurointerventional procedures, performed in 22 hospitals from December 2020 to June 2021, were retrospectively studied. We collected data from a sample of 429 diagnostic and 731 therapeutic procedures. Parameters including dose-area product (DAP), cumulative air kerma (CAK), fluoroscopic time (FT), and total number of image frames (NI) were obtained. RL were calculated as the 3rd quartiles of the distribution. @*Results@#Analysis of 1160 procedures from 22 hospitals confirmed the large variability in patient dose for similar procedures. RLs in terms of DAP, CAK, FT, and NI were 101.6 Gy·cm2, 711.3 mGy, 13.3 minutes, and 637 frames for cerebral angiography, 199.9 Gy·cm2, 3,458.7 mGy, 57.3 minutes, and 1,000 frames for aneurysm coiling, 225.1 Gy·cm2, 1,590 mGy, 44.7 minutes, and 800 frames for stroke thrombolysis, 412.3 Gy·cm2, 4,447.8 mGy, 99.3 minutes, and 1,621.3 frames for arteriovenous malformation (AVM) embolization, respectively. For all procedures, the results were comparable to most of those already published. Statistical analysis showed male and presence of procedural complications were significant factors in aneurysmal coiling. Male, number of passages, and procedural combined technique were significant factors in stroke thrombolysis. In AVM embolization, a significantly higher radiation dose was found in the definitive endovascular cure group. @*Conclusion@#Various RLs introduced in this study promote the optimization of patient doses in diagnostic and therapeutic interventional neuroradiology procedures. Proposed 3rd quartile DAP (Gy·cm2) values were 101.6 for diagnostic cerebral angiography, 199.9 for aneurysm coiling, 225.1 for stroke thrombolysis, and 412.3 for AVM embolization. Continual evolution of practices and technologies requires regular updates of RLs.

Acute Acquired Metabolic Encephalopathy Based on Diffusion MRI

Metabolic encephalopathy is a critical condition that can be challenging to diagnose. Imaging provides early clues to confirm clinical suspicions and plays an important role in the diagnosis, assessment of the response to therapy, and prognosis prediction. Diffusion-weighted imaging is a sensitive technique used to evaluate metabolic encephalopathy at an early stage.Metabolic encephalopathies often involve the deep regions of the gray matter because they have high energy requirements and are susceptible to metabolic disturbances. Understanding the imaging patterns of various metabolic encephalopathies can help narrow the differential diagnosis and improve the prognosis of patients by initiating proper treatment regimen early.

Cerebral Air Embolism: a Case Report with an Emphasis of its Pathophysiology and MRI Findings

Cerebral air embolism (CAE) is a rare complication of various medical procedures. It manifests with symptoms similar to those of typical acute cerebral infarction, however the treatment is quite different. We present a case of arterial CAE that was associated with a disconnected central venous catheter and appeared as punctate dark signal intensities with aliasing artifacts on the susceptibility-weighted filtered phase magnetic resonance image. The susceptibility-weighted filtered phase image can be helpful for diagnosing CAE and the magnetic resonance imaging reflects the pathophysiology of CAE.

Carotid Intraplaque Hemorrhage is Associated with Acute Cerebral Ischemic Events and Progression of Stenosis on Magnetic Resonance Imaging

PURPOSE: To investigate the association of carotid intraplaque hemorrhage (IPH) with acute cerebral ischemic events and progression of stenosis using magnetic resonance (MR) imaging. MATERIALS AND METHODS: From April 2014 to December 2016, 53 patients underwent carotid plaque MR imaging, including magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) sequence. A total of 66 carotid arteries in 53 patients had carotid stenosis, and they were included in this study. Carotid arteries were classified according to the presence of IPH, the age of hemorrhage, and degree of stenosis. We assessed ipsilateral cerebrovascular event rates and progression of stenosis between the IPH and no-IPH groups. RESULTS: Of the 61 carotid arteries assessed, 34 (56%) had IPH, and 27 (44%) had no IPH. Acute cerebral ischemic events were more frequent in the IPH group (47% vs. 22%, P = 0.045), especially in the < 30%-stenosis group (100% vs. 0%, P = 0.028). However, there was no significant difference in the incidence of ischemic events according to the age of hemorrhage (50% vs. 44%, P = 0.492). Among the 61 carotid arteries, 20 carotid arteries had previously undergone carotid artery imaging and were evaluated for plaque progression. The trend for progression of stenosis favored the IPH group versus the no-IPH group, with a marginal P-value (20% ± 12.7 vs. 9.6% ± 5.7, P = 0.063). CONCLUSION: IPH was associated with an increased incidence of acute ischemic events, especially in the mild-stenosis group and it was also associated with progression of stenosis. Evaluation of the carotid IPH by carotid plaque MR could improve discrimination of carotid plaques that cause ischemic events and progression of stenosis.

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

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.

A Rare Case of Viagra Induced Toxic Encephalopathy

Viagra has been prescribed worldwide to treat men with erectile dysfunction. Clinical trials have shown that Viagra may cause various kinds of adverse effects include some central nervous system (CNS) adverse effects. Although extremely rare, toxic encephalopathy also can be one of those effects. This report presents a case of encephalopathy caused by Viagra in correlation with its radiologic findings. Its pharmacologic mechanism and potential effects on the biochemistry of the CNS are reviewed.

Uremic Encephalopathy with Atypical Magnetic Resonance Features on Diffusion-Weighted Images

Uremic encephalopathy is a well-known disease with typical MR findings including bilateral vasogenic or cytotoxic edema at the cerebral cortex or basal ganglia. Involvement of the basal ganglia has been very rarely reported, typically occurring in uremic-diabetic patients. We recently treated a patient who had non-diabetic uremic encephalopathy with an atypical lesion distribution involving the supratentorial white matter, without cortical or basal ganglia involvement. To the best of our knowledge, this is only the second reported case of non-diabetic uremic encephalopathy with atypical MR findings.

Small Cell Carcinoma of the Gallbladder: A Case Report

Small cell carcinoma of the gallbladder is a type of neuroendocrine tumor and very rare. We report ultrasound, CT and MR findings of a small cell carcinoma of the gallbladder that was confirmed by pathology. Small cell carcinoma of the gallbladder was seen as a well-defined mass with peripheral rim enhancement in the gallbladder. In spite of the large size of the mass, direct and extensive invasion of the liver was not detected. However, there were many metastatic lymph nodes.

Comprehension of Two Modalities: Endovascular Coiling and Microsurgical Clipping in Treatment of Intracranial Aneurysms / 신경중재치료의학

A subarachnoid hemorrhage (SAH) is caused by rupture of an intracranial aneurysm. SAHs have significant morbidity and mortality worldwide. Since the 1970s, clipping of intracranial aneurysms has been the standard treatment for SAHs. In the 1990s, a detachable platinum coil device was introduced. This device led to the development of endovascular techniques and reduced the risk of further rupture without a craniotomy. Thus, endovascular coiling has become widely used in patients with ruptured and unruptured intracranial aneurysms (UIAs). Regardless of the treatment technique (clipping or endovascular coiling), the goal of occluding aneurysms is the prevention of rebleeding in ruptured aneurysms and rupture in UIAs. These two treatment techniques have advantages and disadvantages. The question of which technique is more effective in patients with intracranial aneurysms remains controversial. The objective of this article is to provide a comprehensive review of the effect of coiling versus clipping of intracranial aneurysms.

Non-Functioning, Malignant Pancreatic Neuroendocrine Tumor in a 16-Year-old Boy: A Case Report

We report the case of a 16-year-old boy with a solid pancreatic mass which proved to be a nonfunctioning, malignant pancreatic neuroendocrine tumor (PNET). In pediatric patients, malignant pancreatic tumors are rare, especially malignant PNET. When dynamic contrast enhanced MRI showed a well enhancing solid pancreatic tumor on arterial and delayed phases and combined with malignant features, such as vascular invasion, invasion of adjascent organs, and lymphadenopathy, we should include malignant pancreatic neuroendocrine tumor in the differential diagnosis of childhood pancreatic tumors.

Primary Hepatic Choriocarcinoma: A Case Report

Choriocarcinoma is one of the most common malignancies associated with pregnancy. The characteristics of this malignancy include abnormal growth of the trophoblastic tissue, direct invasion of adjacent organs, and distant metastasis; however, it rarely presents extragonadally. Recently, we have experienced a case of primary hepatic choriocarcinoma in a middle-aged-man, which was characterized by a solitary large hepatic mass with central necrosis and hemorrhaging, as well as metastases to the lung and lymph nodes along the hepatoduodenal ligament. We report this case with a review of the literature.

MR Imaging of Intradural Extramedullary Tuberculoma of the Spinal Cord: Report of Two Cases

Intradural extramedullary tuberculoma of the spinal cord is a rare manifestation of the spinal tuberculosis, with a few cases described so far. Recently, we have experienced two cases of extensive intradural extramedullary tuberculoma at the thoracic spine. So, we report these cases with review of the literatures.

Diffusion-Weighted Imaging of Brain Injury Due to Neonatal Hypoglycemia: A Case Report

Profound hypoglycemia results in significant brain injury because glucose is essential for normal brain functioning. We present here a case of transient neonatal hypoglycemia with diffuse brain injury. Magnetic resonance imaging was performed 2 days after onset, and this revealed bilateral regions of restricted diffusion in the parietal, occipital, frontal and temporal lobes. On the T1-weighted images, the regions showed indistinct gray matter-white matter differentiation. There were subtle high signal intensity lesions along the corresponding regions of the FLAIR and T2-weighted images.

A Case of Persistent Trigeminal Artery with Basilar Artery Hypoplasia: MRI, MRA and TCD findings

No abstract available.

Isolated Spontaneous Dissection of the Superior Mesenteric Artery: Percutaneous Stent Placement in Two Patients

Isolated spontaneous dissection of the superior mesenteric artery (SMA) is a rare cause of acute mesenteric ischemia. Two patients were successfully treated by percutaneous stent placement within the main trunk of the SMA. Emphasis is placed on the feasibility of nonsurgical management with percutaneous stent placement of isolated spontaneous dissection of the SMA.

Closure of Carotid Cavernous Fistula by Manual Carotid Jugular Compression / 대한뇌혈관학회지

A patient with symptomatic dural fistula involving the cavernous sinus did intermittant external manual compression of the cervical carotid artery and jugular vein. We observed complete closure of fistula with improvement of symptoms either clinically or at angiography done 6 weeks later, and recommend this technique with clinical follow up and angiography in selected cases before more definitive therapy is employed.

MR Findings of Kallmann Syndrome

Kallman syndrome is characterised by hypogonadotrophic hypogonadism and anosmia. T1 weighted MR coronal images show the bilateral absence or hypoplasia of olfactory bulbs, tracts, and sulci. We report the MR findings of Kallmann syndrome and revew the literature.

A Case of Mosaic Tetrapaloidy

Tetraploidy of human chromosome(92, XXYY) has been described very rarely. Liveborn infant with tetraploidy was reported in only 17 cases(complete 7 cases, mosaicism 10 cases) in the world, and no cases have been reported in Korea. The diploid-tetraploid mosaicism could arise during the early mitosis of the zygote. In one blastomeric cell, the chromosomes replicate but the cytoplasrn does not divide. We report a case of live infant with mosaic tetraploidy detected in lymphocyte(30%) and amniotic cell culture(25%), who presented with multiple congenital anomalies. A brief review of the literature is included.

Diagnostic Usefulness of Tc-99m Tetrofosmin Scintimammography in Patients with Primary Breast Cancer / 대한핵의학회잡지

PURPOSE: The purpose of this study was to evaluate the diagnostic usefulness of scintimammography performed with Tc-99m tetrofosmin in the detection of primary breast cancer. MATERIALS AND METHODS: Sixty-one patients underwent Tc-99m tetrofosmin scintimammography, plain-filrn mammography and ultrasonography. After intravenous injection of Tc-99m tetrofosmin (740 MBq), prone lateral and anterior scintimammograms were obtained. Scintimammogram was visually interpreted as positive, probably positive, probably negative and negative for malignancy. The tumor to background count ratio (T/B) was measured at 5 minutes and 1 hour. Plain-film mammogram was interprcted as one of 5 categories. Final diagnosis was achieved by surgical histology (58/61) or fine needle aspiration (3/61). Of 61 patients, 44 had cancer and 17 had benign lesion. Tumor size of malignant and benign lesions on ultrasonogram were 2.51+/-1.30 cm (range 1-8 cm), 2.50+/-1.35 cm (range 0.96-6 cm), respectively. RESULTS: The sensitivity of plain-film mammography was 88.6%, specificity 58.8%, positive predictive value 84.7%, and negative predictive value 66.7%. The sensitivity of Tc-99m tetrofosmin scintimammography was 90.9%; specificity, 88.2%; positive predictive value, 94.9%; negative predictive value, 78.9%. Of 25 patients with indeterminate degree of suspicion for malignancy on plain-film mammogram, 23 were correctly diagnosed by scintimamography. The T/B at 5 minutes and 1 hour were 3.78+/-2.21, 3.25+/-1.80 respectively. The T/B was decreased significantly at 1 hour (p<0.001). CONCLUSION: Tc-99rn tetrofosrnin scintimammography was useful diagnostic procedure in the detection of primary breast cancer, especially in patients with indeterminate degree of suspicion for malignancy on plain-film mammogram.

Biodistribution and Scintigraphy of Iodine-131-Iododeoxyadenosine in Rats Bearing Breast Cancer / 대한핵의학회잡지

PURPOSE: I-131 labeled (2'-deoxy-2-iodo-p-D-arabinofuranosyl) adenine (IAD) may be involved in DNA synthesis during active proliferation of tumor cells. We conducted this study to find out the biodistribution of IAD and its feasibility for scintigraphic tumor imaging. MATERIALS AND METHODS: Tosyl acetyl-adenosine was dissolved in acetonitrile, and I-131-NaI was added and heated to synthesize IAD. Female Fisher 344 rats innoculated with breast tumor cells were injected witb 0.27 MBq of IAD. Rats were sacrificed at 0.5, 1, 2, 4, 24h and the % of injected dose per gram of tissue (%ID/g) was determined. For scintigraphy, rats bearing breast cancer were administered with 1.11 MBq of IAD and imaging was perforrned after 2 and 24h. Then, rat body was fixed and rnicrotomized slice was placed on radiographic film for autoradiography, RESULTS: %ID/g of tumor wa.' 0.74 (0.5h), 0.73 (1h), 0.55 (2h), 0.38 (4h), and 0.05 (24h), respectively. At 1h after injection, %ID/g of tumor was higher than that of heart (0.34), liver (0.42), spleen (0.47), kidney (0,69), muscle (0.14), bone (0.33) and intestine (0.51). However, %1D/g of tumor was lower than blood (1.06), lung (0.77), and thyroid (177.71). At 4h, %ID/g of tumor in comparison with other tissue did not change. Tumor contrast expressed by tumor to blood ratio was 0.69 and tumor to muscle ratio was 5.11 at 1h. However, these ratios did not improve through 24h. On autoradiogram and scintigraphy at 2 and 24 hour, the tumor was well visualized. CONCLUSION: This results suggest that Ial) may have a potential for tumor scintigraphy. However, further work is needed to improve localization in tumor tissue.