Korean Journal of Radiology最新文献

Objective: To investigate the incidence and timing of late growth of subsolid nodules (SSNs) ≥6 mm after initial 5-year stability, its clinical implications, and the appropriate follow-up strategy.

Materials and methods: This retrospective study included SSNs ≥6 mm that remained stable for the initial five years after detection. The incidence and timing of subsequent growth after five years of stability were analyzed using the Kaplan-Meier method. Descriptive analyses were conducted to evaluate the clinical stage shift in the SSNs, showing growth and the presence of metastasis during the follow-up period. Finally, an effective follow-up CT scan strategy for managing SSNs after a 5-year period of stability was investigated.

Results: Two hundred thirty-five eligible SSNs (211 pure ground-glass and 24 part-solid nodules) in 235 patients (median age, 63 years; 132 female) were followed for additional <1 to 181 months (median, 87.0 months; interquartile range [IQR], 47.0-119.0 months) after 5-year stability. Fourteen SSNs (6.0%) showed growth at two to 145 months (median, 96 months; IQR: 43.0-122.25 months) from the CT scan confirming 5-year stability, with the estimated cumulative incidence of growth of 0.4%, 2.1%, and 6.5% at 1, 5, and 10 years, respectively. Nine SSNs (3.8%) exhibited clinical stage shifts. No lung cancer metastases were observed. Hypothetical follow-up CT scans performed at 5, 10, and 15 years after 5-years of stability, would have detected 5 (36%), 11 (79%), and 14 (100%) of the 14 growing SSNs, along with 4 (44%), 8 (89%), and 9 (100%) of the nine stage shifts, respectively.

Conclusion: During a long-term follow-up of pulmonary SSNs ≥6 mm after 5-years of stability, a low incidence of growth without occurrence of metastasis was noted. CT scans every five years after the initial 5-year stability period may be reasonable.

Objective: To assess the feasibility, efficacy, and safety of targeted embolization for cavernous sinus dural arteriovenous fistulas (CSDAVF).

Materials and methods: This retrospective study investigated patients with CSDAVF who underwent endovascular treatment at a tertiary hospital between October 1991 and March 2023. Treatment strategies were determined based on clinical symptoms and shunt characteristics. Targeted or non-targeted curative embolization was performed to achieve complete shunt occlusion. Initially, targeted embolization, selective occlusion of the shunted pouch while preserving the normal cavernous sinus lumen, was conducted, should that fail, non-targeted embolization was performed. In contrast, palliative embolization solely reduced shunt flow. Clinical signs, imaging characteristics, and outcomes were evaluated according to the agreed treatment strategy.

Results: In total, 198 patients with CSDAVF (mean age 59.0 ± 12.1 years, 23.2% male) participated in this study. Of which, 94 patients (47.5%) were treated with targeted embolization, 75 (37.9%) with non-targeted embolization, and 29 (14.6%) with palliative treatment. For patients undergoing curative embolization, 55.7% (94/169) successfully achieved targeted embolization; this procedure was usually used to treat focal fistulas (restrictive or late-restrictive types), whereas diffuse fistulas (proliferative type) often underwent non-targeted or palliative embolization. For patients that underwent targeted embolization, the rate of complete or near-complete occlusion on immediate post-treatment digital subtraction angiography was 93.6% (88/94), with a complication rate of 2.1% (2/94), symptom improvement rate of 96.8% (91/94), and retreatment rate of 5.3% (5/94). No serious complications were reported during follow-up.

Conclusion: When successful, targeted embolization of CSDAVF causes low rates of cranial nerve palsy, retreatment, and good clinical outcomes.

Objective: To survey experts' opinions in abdominal radiology (radiologists) and pancreas-specialized gastroenterology (pancreatologists) in South Korea regarding diagnosing and managing pancreatic cystic neoplasms (PCNs).

Materials and methods: Between August 25, 2023, and October 5, 2023, an online survey was conducted among members of the Korean Society of Abdominal Radiology and the Korean Pancreatobiliary Association via email invitation.

Results: The responses from 100 radiologists and 41 pancreatologists were analyzed. Of the respondents, 55.3% (78/141) reported seeing more than 50 patients or reading more than 50 exams related to PCN each month. The most common and preferred diagnostic modality for PCN was contrast-enhanced computed tomography (CECT), favored by 87.8% (36/41) of pancreatologists. When discrepancies arose between CECT or magnetic resonance imaging (MRI) and endoscopic ultrasound, 31.2% (44/141) of the respondents opted for multidisciplinary team discussion, whereas 29.1% (41/141) chose short-term follow-up using CECT or MRI. A total of 88.7% (125/141) of the respondents adhered to the 2017 International Association of Pancreatology (IAP) guidelines in their practice. Among the radiologists, 51.0% (51/100) endorsed a cut-off value of 5 mm for enhancing mural nodules, and 22.0% (22/100) supported a 5 mm/2 yr growth rate in the IAP guidelines v.2017. Additionally, 73.0% (73/100) of radiologists favored discontinuing surveillance, whereas 41.5% (17/41) of pancreatologists disagreed with stopping surveillance.

Conclusion: The survey underscores the clinical burden PCN poses and identifies CECT as the foremost diagnostic tool. Variability was noted in the terminology, differential diagnosis, approaches for resolving discrepancies between imaging examinations, and opinions on surveillance discontinuation among the respondents as a whole, as well as between radiologists and pancreatologists. Although the 2017 IAP guidelines are primarily followed, there remains a level of dissatisfaction with risk stratification among radiologists. This highlights the need for more standardized diagnostic algorithms and improved consensus among specialists to address these challenges.

Objective: There is controversy among different guidelines regarding the use of thermal ablation to treat clinical T1a renal cell carcinomas with tumor sizes ranging from 3.1-4 cm. Therefore, we compared oncological outcomes between heat-based thermal ablation (hTA) and cryoablation (CA) in patients with solid T1a renal cell carcinomas, including those with a tumor size ≤3 cm and a tumor size of 3.1-4 cm.

Materials and methods: Within the Surveillance, Epidemiology, and End Results database (2000-2019), we identified patients with clinical T1a renal cell carcinomas that were histologically confirmed and treated with hTA or CA. After propensity score matching using a 1:1 ratio, the overall survival (OS) and cancer-specific survival (CSS) were estimated and compared between the two methods. Cancer-specific mortality (CSM) was also analyzed, considering other-cause mortality as a competing risk.

Results: Of the 3513 assessable patients, 1426 (40.6%) and 2087 (59.4%) were treated with hTA and CA, respectively. After propensity score matching, the hTA and CA groups included 1393 and 1393 patients, respectively. hTA was associated with shorter OS than CA with a hazard ratio of 1.17 (95% confidence interval, 1.04-1.32; P = 0.010). The hTA and CA groups did not reveal statistically significant differences in CSS with a hazard ratio of 1.07 (95% confidence interval, 0.76-1.50; P = 0.706). The hTA and CA groups did not show statistically significant differences in CSM (P = 0.849). However, the hTA group showed a significantly higher other-cause mortality (P = 0.011).

Conclusion: In patients with clinical stage T1a renal cell carcinomas, hTA was comparable to CA in terms of CSS and CSM. However, hTA resulted in a slightly shorter OS than CA. Large-scale randomized clinical trials are required to obtain more robust evidence.

Objective: We aimed to describe the [¹⁸F]fluorodeoxyglucose (FDG) and prostate-specific membrane antigen (PSMA) PET/CT findings in Korean men with advanced metastatic castration-resistant prostate cancer (mCRPC).

Materials and methods: The results of paired FDG and PSMA PET/CT examinations performed in 42 consecutive men with prostate cancer for treatment planning after failure of anti-androgen therapy and chemotherapy were studied. Tumor lesions with FDG or PSMA uptake intensity higher than that of the liver on visual review were considered positive and noted per patient and tumor site (prostate bed, lymph node, bone, and visceral organ). The presence of unequivocally discordant FDG and PSMA uptake patterns in tumor lesions was assessed. Patients were grouped according to the total tumor volume as seen on each PET/CT scan, and the clinical findings between the patient groups were compared using the Mann-Whitney U test.

Results: On patient-based analysis, the image findings were PSMA+/FDG- in 2 patients, PSMA-/FDG+ in one, and PSMA+/FDG+ in 39 patients. On site-based analysis, the discordance (PSMA+/FDG- or PSMA-/FDG+) rate was 9.5% (4/42) for prostate/bed, 11.9% (5/42) for lymph nodes, 9.5% (4/42) for bones, and 11.9% (5/42) for visceral organs. FDG uptake was higher than PSMA uptake in at least one tumor site in 54.8% (23/42) of patients. Patients with greater total tumor volume on FDG PET/CT than that on PSMA PET/CT ("FDG-dominant pattern") accounted for 28.6% (12/42), and they had significantly shorter time from diagnosis (median 25 months vs. 62 months, P = 0.049), and higher aspartate aminotransferase (median 28.5 vs. 22.5, P = 0.027) and lactate dehydrogenase (median 341.5 vs. 224.5, P = 0.010) levels.

Conclusion: Most patients with advanced mCRPC had tumors with positive findings on both FDG and PSMA PET/CT. However, the uptake patterns varied; 54.8% of the patients had tumor(s) with FDG uptake greater than PSMA uptake, and FDG-dominant pattern was noted in 28.6% of the patients.

Objective: The aim of this study was to analyze the origins of prostatic arteries (PAs) in the Korean population and compare them with those reported in the literature.

Materials and methods: From April 2018 to February 2024, 108 male (mean age ± standard deviation: 71.6 ± 9.7 years) with lower urinary tract symptoms (n = 102) or refractory hematuria (n = 6) underwent prostatic artery embolization (PAE). Computed tomography and angiography images were retrospectively reviewed. The branching pattern of the internal iliac artery (IIA) was classified according to the Yamaki system. The origin of the PA was categorized using the de Assis definition, and the incidence of each type was recorded. A systematic literature review was conducted and the most common types of PA were investigated.

Results: PAE was successfully implemented on 211 of the 216 pelvic sidewalls. PA cannulation failed in five sidewalls due to a steno-occlusive state. The most common IIA type was type A, in which the IIA was divided into the superior gluteal artery and gluteal-pudendal trunk (77%). Of 226 PAs analyzed, including 15 in 211 sidewalls exhibiting dual PAs, the most common PA origin was the internal pudendal artery (type IV, 35%), followed by the superior vesical (type I, 25%) and obturator (type III, 21%) arteries. Anterior division of IIA (type II) was less common (10%). Type V (uncommon origins) occurred in 8% of cases, including five distal internal pudendal arteries, four quadfurcations, three inferior gluteal arteries, three trifurcations, two medial femoral circumflex arteries, and two rectal arteries. Two of the five patients with surgically or endovascularly altered anatomy were successfully treated via PAs originating from the medial femoral circumflex arteries. Globally, type I is the most common PA type.

Conclusion: In the Korean population, the most common IIA pattern and PA origin were types A and IV, respectively.

Objective: The aim of this study was to investigate postoperative imaging findings of patients who underwent breast-conserving surgery for cancer and reconstruction with MegaDerm^® (sheet-type and pellet-type), analyzing false positives and recurrences, using multi-modality images.

Materials and methods: This study included 201 women (age range: 28-81 years, mean age ± standard deviation: 53.2 ± 8.6 years) who underwent breast-conserving surgery and immediate reconstruction with MegaDerm^®. Post-surgery, each patient underwent at least one mammography (MG), ultrasonography (US), and MRI, totaling 713 MG, 1063 US, and 607 MRI examinations. Postoperative images were reviewed separately for the two types of MegaDerm^®, and suspicious imaging findings (false positives and recurrences) were analyzed, with a particular focus on the findings in direct contact with MegaDerm^®.

Results: MegaDerm^® appeared as a circumscribed mass with homogeneous iso- or high density on MG, posterior shadowing on US, and no enhancement on MRI. Calcification was more common and increased in size in sheet-type MegaDerm^®, while pellet-type often exhibited irregular margins. Nine out of 17 false positives had suspicious findings in direct contact with MegaDerm^®, and six out of nine recurrences showed similar findings. Common suspicious findings included calcifications, asymmetries, and MegaDerm^® irregularities on MG; masses and MegaDerm^® irregularities on US; and enhancing masses and MegaDerm^® irregularities with enhancement on MRI. Notably, MegaDerm^® irregularity with calcification was observed on MG and US in only one recurrence case. In 44.4% (4/9) of false-positives in direct contact with MegaDerm^®, suspicious findings showed no change or resolution on follow-up.

Conclusion: Suspicious imaging findings in direct contact with MegaDerm^® may be associated with false positives or recurrences. Therefore, it is essential to recognize these characteristic findings and review the patient's history of MegaDerm^® insertion when in doubt.

Objective: To evaluate the effects of microwave (MW) power and antenna approach methods on extrahepatic tumor seeding and ablation zone size using an ex vivo subcapsular tumor-mimic model.

Materials and methods: Forty-one subcapsular tumor mimics were prepared by injecting a mixture of contrast media into bovine liver blocks. Ablation was performed using low- and high-power protocols (75 W and 100 W for 4 and 3 minutes, respectively). The antenna approach was assessed in two directions: parallel and perpendicular to the capsule. CT scans were obtained before and after the ablation to detect contrast leakage on the hepatic surface. The presence of leakage, ablation zone size, and the timing of the first popping sound were compared between the two groups.

Results: Five cases of contrast leakage were observed in the low-power group (n = 21) and 17 in the high-power group (n = 20) (23.8% vs. 85.0%, P < 0.001). Contrast leaks were less frequently observed in the low-power protocol compared to the high-power protocol, regardless of the antenna approach (18.2% [2/11] vs. 80.0% [8/10], P = 0.009 for parallel access; 30.0% [3/10] vs. 90.0% [9/10], P = 0.020 for perpendicular access). The timing of the first popping sound was significantly delayed in the low-power group compared to the high-power group (137.7 ± 51.4 s vs. 77.8 ± 31.4 s, P < 0.001). The size of the ablation zone did not differ significantly between the two power groups (P = 0.415). The parallel and perpendicular antenna approaches did not show significant differences in the number of contrast leaks, popping sound timing, or ablation-zone size (P = 0.536, 0.463, and 0.271, respectively).

Conclusion: Low-power MW ablation may be superior to a high-power protocol in reducing the risk of tumor seeding in subcapsular tumors, regardless of the antenna approach.

Active surveillance (AS) has been widely adopted as an alternative to immediate surgery owing to the indolent nature and favorable outcomes of papillary thyroid microcarcinoma (PTMC). AS is generally recommended for tumors measuring ≤1 cm without aggressive cytological subtypes, risk of gross extrathyroidal extension (ETE), lymph node metastasis (LNM), or distant metastasis. AS requires careful patient selection based on various patient and tumor characteristics, and ultrasound (US) findings. Moreover, during AS, regular US is performed to monitor any signs of tumor progression, including tumor growth, new US features of potential gross ETE, and LNM. Therefore, appropriate imaging-based assessment plays a crucial role in determining whether AS or surgery should be pursued. However, detailed recommendations concerning US evaluation are currently insufficient, necessitating the formulation of this guideline. The Korean Society of Thyroid Radiology has developed a consensus statement for low-risk PTMC, covering US assessment methods when considering AS as a management option and conducting follow-up imaging tests during AS. This guideline aims to provide optimal scientific evidence and expert opinion consensus regarding a standardized US-based assessment protocol for low-risk PTMC.