濱本 耕平

Abstract Despite advances in diagnostic imaging and interventional techniques, pancreatic pseudoaneurysms remain a life-threatening complication of pancreatitis. Presentation varies among patients and may include intra-abdominal, retroperitoneal, or gastrointestinal bleeding and bleeding into the pancreatic or common bile duct. We present a unique case of a 74-year-old man with a history of heavy alcohol consumption who presented with a haematoma surrounding the caudate lobe of the liver. Initially, alcoholic cirrhosis and a ruptured hepatocellular carcinoma were suspected. Therefore, transarterial embolization (TAE) of the caudate branch of the hepatic artery was performed. However, 3 months later, the patient experienced abdominal pain with a lesser sac haematoma and a seemingly interconnected pancreatic cyst. One month later, a pseudoaneurysm appeared in the pancreatic cyst. TAE was successfully performed for the pseudoaneurysm, and the patient showed no signs of recurrence during the 1-year follow-up.

PURPOSE: Complete androgen insensitivity syndrome (CAIS) and Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS) share common clinical features such as female phenotype, vaginal hypoplasia, and primary amenorrhea. Magnetic resonance imaging (MRI) is performed to investigate the cause of primary amenorrhea. However, the MRI features are also similar in both disorders. They are ultimately diagnosed by chromosome testing, but there is a possibility of misdiagnosis if chromosome testing is not performed. This study aimed to identify MRI features that are useful for differentiating CAIS from MRKHS. METHOD: This multicenter retrospective study included 12 patients with CAIS and 19 patients with MRKHS. Three radiologists blindly evaluated the following features: (1) detection of vagina, (2) detection of nodular and cystic structures in the lateral pelvis; undescended testicles and paratesticular cysts in CAIS and rudimentary uteri and ovaries in MRKHS, (3) their location, (4) number of cysts in the cystic structures, and (5) signal intensity on diffusion-weighted images (DWI) and apparent diffusion coefficient (ADC) values of the nodular structures. Statistical comparisons were performed using Mann-Whitney U and Fisher's exact tests. RESULTS: Compared with MRKHS, the CAIS group showed significantly detectable vagina, more ventrally located nodular and cystic structures, fewer cysts within the cystic structures, and nodular structures with higher signal intensity on DWI and lower ADC values. CONCLUSIONS: MRI features of detectable vagina, location of nodular and cystic structures, number of cysts within the cystic structures, signal intensity on DWI and ADC values of the nodular structures were useful in differentiating CAIS from MRKHS.

A 44-year-old man presented with a chief complaint of constipation. Initial contrast-enhanced CT showed extensive bowel wall thickening, mainly in the left colon, with a thin cord-like inferior mesenteric vein (IMV), in contrast to ectatic mesenteric venous branches, suggesting bowel ischaemia owing to venous stasis. One month later, at the time of symptom exacerbation, CT angiography showed a cord-like IMV and ectatic mesenteric venous branches with early enhancement, suggesting the presence of an arteriovenous fistula (AVF). Owing to the progression of bowel ischaemia and necrosis with peritonitis, emergency surgery was performed. Surgical specimens showed focal myointimal hyperplasia of the proximal mesenteric veins in both ischaemic and non-ischaemic lesions of the resected colon, thus leading to the diagnosis of idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) when combined with the clinical and imaging findings. IMHMV is a bowel ischaemic disease caused by non-thrombotic venous obstruction that requires bowel resection and has been suggested to be associated with AVF. Cord-like IMV and AVF in the mesentery are important CT findings that characterize IMHMV. CT angiography is useful in diagnosing IMHMV.

Lymphatic ascites following pelvic and para-aortic lymphadenectomy is a well-known complication. Surgical treatment and interventional radiology are required in a few cases. To determine the appropriate treatment strategy, it is important to preoperatively detect the presence and location of lymphatic leakage. However, the methods have yet to be established. We report a case in which lymphoscintigraphy with single-photon emission computerized tomography/computed tomography (SPECT/CT) was performed to evaluate pelvic lymphorrhea that occurred following total hysterectomy with pelvic and para-aortic lymphadenectomy for stage IIIA uterine sarcoma. Lymphoscintigraphy with SPECT/CT showed leakage of radioisotopes into the pelvic space, and intranodal lymphangiography was performed based on these findings. Following the procedure, the pelvic lymphorrhea improved, and no radioisotope leakage was confirmed by re-evaluation with lymphoscintigraphy with SPECT/CT. Our case indicates that lymphoscintigraphy with SPECT/CT may be useful for detecting the precise site of lymphatic leakage before interventional radiology or surgery.

KEY CLINICAL MESSAGE: With the aging of the population, physicians need to pay more attention to assessing the presence or absence of pelvic fractures and urinary retention associated with urethral injury due to such fractures in the elderly when falling from bicycles. ABSTRACT: Walking ability does not rule out the presence of pelvic fractures. Many geriatric patients are likely to fall off bicycles. Physicians should pay more attention when assessing complications related to urethral trauma caused by pelvic fractures in the elderly after falling from bicycles.

A 74-year-old woman was admitted with hypercalcemia and prolonged disturbance of consciousness. The left buttock to the anterior aspect of the left thigh was swollen and erythematous, with a collection of 1.0-cm large, firm, elastic nodules distributed in a zosteriform pattern in the L1-L4 region. Based on autopsy findings, a very rare case of Cobb syndrome was diagnosed due to a spinal vascular malformation at the Th12-L4 level and L5 vertebral hemangioma. Cobb syndrome-associated cutaneous metastasis extending along the same metamere was complicated by immunohistochemically proven parathyroid hormone-related protein-producing advanced bladder carcinoma in this case.

BACKGROUND AND PURPOSE: Subcortical band heterotopia (SBH) is a malformation of cortical development diagnosed via MRI. Currently, patients with SBH are classified according to Di Donato's classification. We aimed to show a variation of SBH and the usefulness of double inversion recovery (DIR) images. METHODS: We retrospectively reviewed the MRI findings of 28 patients with SBH. The patients were classified according to Donato's classification by using conventional MR images, and their DIR findings were reviewed. RESULTS: Of 28 patients, 20 were grade 1 and 8 were grade 2 according to Di Donato's classification. In 15 of 28 patients, the following four types of atypical MRI findings were detected: asymmetry distribution (four cases), coexistence of thin and thick SBH (five cases), and DIR faint abnormal signal intensity in subcortical white matter (five cases) and in deep white matter (five cases). The latter two types were detected on DIR alone and have not been reported. Additionally, these were identified only in the mild group (Di Donato's classification 1-1 or 1-2). CONCLUSION: DIR is a useful MRI sequence for detecting faint white matter signal abnormalities, and it can aid in the accurate classification of SBH and identification of its variations, which may reflect the pathology of SBH.

We report a case of a deep femoral artery aneurysm with a ligated proximal artery that was successfully managed with endovascular therapy. An 84-year-old male was referred to our institute with a history of surgical resection of a left ruptured deep femoral artery aneurysm wherein another aneurysm was found on the peripheral side. Proximal artery ligation of the peripheral lesion was performed. The residual aneurysm had gradually enlarged after surgery, and contrast-enhanced computed tomography showed contrast effects in the aneurysm that extended to the distal artery. The aneurysm was successfully treated by direct percutaneous puncture embolization with N-butyl-cyanoacrylate.

Contrast-enhanced CT and MR angiography are widely used for follow-up of visceral artery aneurysms after coil embolization. However, potential adverse reactions to contrast agents and image deterioration due to susceptibility artifacts from the coils are major drawbacks of these modalities. Herein, we introduced a novel non-contrast-enhanced MR angiography technique using ultra-short TE combined with a modified signal targeting alternating radio frequency with asymmetric inversion slabs, which could provide a serial hemodynamic vascular image with fewer susceptibility artifacts for follow-up after coil embolization.

Composite pheochromocytoma is an extremely rare tumor that comprises a pheochromocytoma and an embryologically related neurogenic tumor, such as ganglioneuroma, ganglioneuroblastoma, neuroblastoma, or peripheral nerve sheath tumor. A 46-year-old male with hypertension, elevated plasma catecholamine levels, and suspected pheochromocytoma presented to the National Defense Medical College Hospital. CT and MRI showed two adjacent masses in the left adrenal gland; one was a 6 cm cephalic lesion and the other was a 1.5 cm caudal lesion. Only the 1.5 cm caudal mass showed uptake on ¹²³I-metaiodobenzylguanisine single photon emission CT/CT. Pheochromocytoma was suspected and a left adrenalectomy was performed. Pathology confirmed that the 6 cm mass was a ganglioneuroma and the 1.5 cm mass a pheochromocytoma, with cellular intermingling at their border. The two masses were diagnosed as a composite pheochromocytoma–ganglioneuroma. This is the first report in which the two components of a composite pheochromocytoma can be clearly distinguished in the pre-operative images. If a patient with clinically suspected pheochromocytoma has different components from a typical pheochromocytoma, composite pheochromocytoma should be considered.

We present a case of subcapsular hepatic hemorrhage with a concomitant diffuse arterioportal shunt successfully treated with transcatheter arterial embolization. An 85-year-old man with duodenal carcinoma developed hemorrhagic shock three days after pancreaticoduodenectomy. Contrast-enhanced computed tomography revealed an extensive subcapsular hepatic hematoma with extravasation. At the same time, diagnostic angiography showed innumerable foci of petechial extravasation from disrupted isolated arteries and the right inferior phrenic artery. In addition, a comorbid diffuse arterioportal shunt in the hematoma area was detected. We performed transcatheter arterial embolization on the peripheral side of the hepatic artery while preserving the proximal portion. Subsequently, the transcatheter arterial embolization for the right inferior phrenic artery was also performed. Complete hemostasis and occlusion of the arterioportal shunt were successful without fulminant liver failure.

We present two cases of external iliac artery perforation occurring after endovascular interventions successfully treated with direct closure using super-selective transcatheter coil embolization. Two patients, one 78-year-old man and one 78-year-old woman, underwent cardiac catheterization via the right femoral approach for coronary artery disease and atrial fibrillation. Following the procedures, both patients suffered severe acute hypotension, and contrast-enhanced computed tomography revealed a massive retroperitoneal hematoma due to perforation of the right external iliac artery. We attempted direct perforation site closure with super-selective transcatheter embolization using microcoils and achieved complete hemostasis in both cases. Our technique could be an alternative treatment option for external iliac artery perforations associated with the endovascular intervention.

BACKGROUND: Massive hemoptysis after thoracic aortic aneurysm (TAA) repair is a rare but potentially lethal condition. Endovascular management is a challenging treatment option due to the complexity of culprit vessel access. CASE PRESENTATION: An 81-year-old woman was referred to our hospital with massive hemoptysis. She had a history of graft replacement and thoracic endovascular aortic repair (TEVAR) for dissecting TAA. Computed tomography (CT) showed massive atelectasis with hematoma in the left lower lung lobe adjacent to the descending aortic aneurysm treated with TEVAR. Contrast-enhanced CT revealed a pseudoaneurysm and proliferation of abnormal vessels at the peripheral side of the left pulmonary ligament artery (PLA) in the atelectasis. The PLA continued to the right subscapular artery via a complex collateral pathway. Diagnostic angiography of the right subcapsular artery revealed a pseudoaneurysm and abnormal vessels at the peripheral side of the left PLA with a systemic-pulmonary artery shunt. Transcatheter arterial embolization (TAE) for the left PLA via the collateral pathway with N-butyl cyanoacrylate achieved complete embolization. The patient's hemoptysis was controlled and she was discharged. CONCLUSIONS: Here we presented a case of massive hemoptysis due to PLA disruption that occurred after TAA repair. TAE via a complex collateral pathway is a feasible and effective treatment for hemoptysis, even in patients who have undergone surgical or endovascular TAA repair.

This study aimed to evaluate the diagnostic value of ultrasonographic parameters as an indicator for predicting regional nerve block success. Ultrasound-guided sciatic nerve block was performed in seven dogs using either 2% mepivacaine (nerve-block group) or saline (sham-block group). The cross-sectional area (CSA), nerve blood flow (NBF), and shear wave velocity (SWV) of the sciatic nerve (SWVN), SWV of the biceps femoris muscle (SWVM), and their ratio (SWVNMR) were measured at 0, 30, 60, and 90 min after the nerve block as well as the change rate of each parameter from the baseline. A receiver operating characteristic (ROC) curve analysis was performed to determine the diagnostic value of each parameter in the prediction of nerve block success. No significant changes were observed in the CSA or NBF in association with the nerve block. The SWVN and SWVNMR in the nerve-block group were significantly higher than those in the sham-block group at 90 min and at 30, 60, and 90 min, respectively (p < 0.05). The change rates of SWVN and SWVNMR in the nerve-block group were significantly higher than those in the sham-block group at all time points (p < 0.05). The ROC curve analysis showed that SWVN had a moderate diagnostic accuracy (area under the curve [AUC], 0.779), whereas SWVNMR and change rates of SWVN and SWVNMR had a high diagnostic accuracy (AUC, 0.947, 0.998, and 1.000, respectively). Ultrasonographic evaluation of the SWVN and SWVNMR could be used as indicators for predicting nerve block success.

PURPOSE: The purpose of this study was to evaluate the diagnostic performance of ultra-short echo time magnetic resonance imaging (UTE MRI) in the assessment of pulmonary arteriovenous malformation (PAVM). METHODS: Eighteen consecutive patients (mean [± standard deviation] age, 48.6 ± 16.8 years) with 46 untreated PAVMs who underwent and thin-section computed tomography (CT) and UTE MRI with a 1.5-Tesla and 3-Tesla unit were retrospectively assessed. Two radiologists evaluated the diagnostic capabilities of UTE MRI for the detection and classification of PAVMs with reference to CT. Sensitivity, specificity, and kappa statistics were calculated with reference to CT. We also compared the differences in PAVM measurements between CT and MRI. RESULTS: The sensitivity and specificity of UTE-MRI for the detection of PAVMs were 89.1% and 100%, respectively, for reader 1 and 87.0% and 100%, respectively, for reader 2. In the classification of PAVMs, inter-modality agreement in reader 1 and 2 were both substantial (κ = 0.78 and 0.69, respectively). The measurements of the PAVM feeding artery and sac on CT and MRI were strongly correlated in both readers 1 and 2 (R2 = 0.981 and 0.983, respectively). Both readers 1 and 2 slightly underestimated the diameter of the PAVM feeding artery and sac on UTE MRI (p < 0.001). CONCLUSION: This study indicates that UTE MRI is a feasible and promising modality for noninvasive assessment of PAVMs.

A flow-diverter (FD) device is a well-established tool for the treatment of unruptured intracranial aneurysms. Time-of-flight (TOF) MR angiography (MRA) is widely used for postoperative assessment after the treatment with FD; however, it cannot fully visualize intra-aneurysmal and intrastent flow signals due to the magnetic susceptibility from the FD. Recently, the utility of MRA with ultra-short TE (UTE) sequence and arterial spin labeling technique in assessing the therapeutic efficacy of intracranial aneurysms treated with metallic devices has been reported, but long image acquisition time is one of the drawbacks of this method. Herein, we introduce a novel UTE MRA using the subtraction method that enables the reduction in susceptibility artifacts with a short image acquisition time.

Pulmonary arteriovenous malformation (PAVM) is a rare vascular anomaly, for which transcatheter embolization with metallic coils is the standard of care. Although detecting recanalization after embolotherapy is crucial, direct visualization of residual flow with computed tomography or magnetic resonance (MR) imaging is generally difficult due to metal artifacts. We present a case of recanalized PAVM after coil embolization detected by ultra-short echo time MR angiography using a modified signal targeting with an alternative radio frequency spin labeling technique.

A 25-year-old man with a massive traumatic subcutaneous hematoma in his back was transferred to our emergency department. Contrast-enhanced computed tomography revealed a pseudoaneurysm with extravasation within the hematoma. The patient was unable to take a supine position due to the massive back hematoma. We thus performed a transcatheter embolization of bilateral cervical branches with the patient in the prone position, via a radial artery. After two embolizations, successful hemostasis was achieved. The prone transradial catheterization technique is useful for embolization in patients who cannot be in the supine position.

OBJECTIVES: This study aimed to assess the diagnostic accuracy of computed tomography (CT) and time-resolved magnetic resonance angiography (TR-MRA) for patency after coil embolization of pulmonary arteriovenous malformations (PAVMs) and identify factors affecting patency. METHODS: Data from the records of 205 patients with 378 untreated PAVMs were retrospectively analyzed. Differences in proportional reduction of the sac or draining vein on CT between occluded and patent PAVMs were examined, and receiver operating characteristic analysis was performed to assess the accuracy of CT using digital subtraction angiography (DSA) as the definitive diagnostic modality. The accuracy of TR-MRA was also assessed in comparison to DSA. Potential factors affecting patency, including sex, age, number of PAVMs, location of PAVMs, type of PAVM, and location of embolization, were evaluated. RESULTS: The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of CT were 82%, 81%, 77%, 85%, and 82%, respectively, when the reduction rate threshold was set to 55%, which led to the highest diagnostic accuracy. The sensitivity, specificity, PPV, NPV, and accuracy of TR-MRA were 89%, 95%, 89%, 95%, and 93%, respectively. On both univariable and multivariable analyses, embolization of the distal position to the last normal branch of the pulmonary artery was a factor that significantly affected the prevention of patency. CONCLUSIONS: TR-MRA appears to be an appropriate method for follow-up examinations due to its high accuracy for the diagnosis of patency after coil embolization of PAVMs. The location of embolization is a factor affecting patency. KEY POINTS: • Diagnosis of patency after coil embolization for pulmonary arteriovenous malformations (PAVMs) is important because a patent PAVM can lead to neurologic complications. • The diagnostic accuracies of CT with a cutoff value of 55% and TR-MRA were 82% and 93%, respectively. • The positioning of the coils relative to the sac and the last normal branch of the artery was significant for preventing PAVM patency.

BACKGROUND: Peak skin dose (PSD) is closely associated with skin radiation injuries such as skin ulcers in percutaneous coronary intervention (PCI). Although PSD is greater in PCI for chronic total occlusion (CTO) lesions as compared with non-CTO lesions, the determinants of PSD in CTO-PCI are not fully understood. The purpose of this study was to investigate the clinical factors associated with excess PSD in PCI for CTO. METHODS: The study population included a total of 220 CTO-PCI cases that were divided into a standard PSD group (<2 Gy, n = 187) and an excess PSD group (≥2 Gy, n = 33). Clinical, lesion, and procedural characters were compared between the 2 groups. Multivariate logistic regression was performed to investigate the clinical factors associated with excess PSD. RESULTS: Body surface area (BSA) was significantly higher in the excess PSD group (1.85 ± 0.24 m2) than the standard PSD group (1.71 ± 0.18 m2) (p = 0.001). The J-CTO score was significantly higher in the excess PSD group (2.51 ± 1.28) than the standard PSD group (1.60 ± 1.13) (p < 0.001). Multivariate logistic regression analysis revealed that BSA (0.1 mm increase: OR 1.663, 95% CI 1.300-2.128, p < 0.001) and J-CTO score (1-point increase: OR 2.015, 95% CI 1.322-3.071, p = 0.001) were significantly associated with excess PSD. CONCLUSIONS: A large BSA and high J-CTO score were significantly associated with excess PSD. It is important to pay special attention to CTO patients who have a large BSA and/or high J-CTO score to reduce patient's PSD.

Antiangiogenic agents, such as ramucirumab, should be cautiously administered along with radiotherapy because of the enhanced risk of adverse events.

A 52-year-old woman with right-sided breast cancer was diagnosed with a left pulmonary arteriovenous malformation (PAVM) by computed tomography (CT). Percutaneous embolization of the PAVM after treatment of the breast cancer was scheduled to prevent a paradoxical embolic event. She underwent lumpectomy, followed by systemic chemotherapy in combination with tangential field radiotherapy. Subsequently, she received endocrine therapy with tamoxifen, anastrozole, and exemestane, sequentially. There was no change in the PAVM on CT performed during the administration of anastrozole. Subsequently, CT performed five months after switching to exemestane showed obviously decreased size of the affected vessels, and the sac had almost disappeared. To the best of our knowledge, this is the first case report to describe the spontaneous regression of a PAVM during endocrine therapy for breast cancer.

BACKGROUND: Skin radiation injuries, especially radiation ulcers, are serious side effects caused by ionizing radiation during percutaneous coronary interventions (PCI). Because skin radiation injuries are closely associated with the peak skin dose, it is important to minimize the peak skin dose. The aim of the present study was to investigate the determinants of greater peak skin dose in current PCI. METHODS: We included 707 consecutive coronary artery lesions, and divided them into an excess radiation group (n = 26; defined as peak skin dose ≥2 Gy) and a standard radiation group (n = 681; defined as peak skin dose <2 Gy). Clinical, lesion, and procedural characteristics were compared between the 2 groups. Univariate and multivariate logistic regression analyses were performed to identify determinants of the excess radiation group. RESULTS: A multivariate logistic regression analysis revealed that body surface area (BSA) [0.1 m2 increase: odds ratio (OR) 1.39, 95% confidence interval (CI) 1.13-1.71, P < 0.01], PCI to a right coronary artery (RCA) (OR 3.11, 95% CI 1.35-7.17, P < 0.01), and PCI to a chronic total occlusion (CTO) (OR 6.69, 95% CI 2.65-16.87, P < 0.01) were significantly associated with the excess radiation group. CONCLUSIONS: Greater BSA, PCI to RCA lesions, and PCI to CTO lesions were significantly associated with excess radiation dose. The first step in the prevention of radiation injuries in current PCI will be to recognize these risk factors.

An 83-year-old man with a history of carbon ion radiotherapy for hepatocellular carcinoma nine years ago presented to a primary care hospital with a fever and abdominal pain. He underwent computed tomography, which revealed the rupture of a hepatic pseudoaneurysm close to the fiducial marker for carbon ion radiotherapy and bleeding into the bile duct. He was successfully treated with transcatheter arterial embolization. Thereafter, re-rupture occurred from a site proximal to the first rupture, and this was treated similarly. It is necessary to be alert for not only tumor recurrence but also pseudoaneurysm occurrence after carbon ion radiotherapy.

Leiomyosarcoma of the inferior vena cava is a rare malignant tumor originating from smooth muscle cells of the vascular media. Its preoperative diagnosis by conventional noninvasive examinations such as abdominal ultrasonography, X-ray computed tomography, and magnetic resonance imaging, may be difficult because of their nonspecific findings. We present the case of a 72-year-old woman with leiomyosarcoma of the inferior vena cava diagnosed by intravascular ultrasonography.

We report a case of intractable chylothorax after right upper lobectomy and nodal dissection via median sternotomy for lung cancer in a 67-year-old man. Lymphangiography (LAG) with lipiodol and sequential computed tomography showed the thoracic duct in the left posterior mediastinum and massive lymphatic leakage in the anterior and middle mediastinum. The Chylous leakage was resolved by LAG with lipiodol. Our findings suggest that variation of the thoracic duct should be evaluated by LAG when intractable chylothorax or chylomediastinum develops after anterior mediastinal surgery.

【背景】現行の卒後臨床研修制度下で放射線科研修は必修ではないが，自治医科大学附属さいたま医療センターでは70～80％の初期研修医が自由選択期間に放射線科研修を選択しており，研修ニーズは高いと考えられる。【目的】研修医の当センター放射線科研修に対するニーズとそれに適した研修内容に関して検討する。【方法】当センターにおいて放射線科研修を選択した30名の初期研修医に対して，研修開始前希望調査および無記名による研修終了時アンケートを行った。【結果】研修前の希望調査では救急疾患の読影研修希望が最も多く，研修終了時のアンケートでは症例集を利用した救急画像のレビュー形式の指導が高評価であった。研修中に勉強になったこととして，救急疾患や頭部MRIの読影を挙げる研修医が多かった一方で，終了後のアンケートでは救急疾患の読影，頭部CT/MRIや外傷の読影といった救急診療に関わる読影が不足しているとの意見も多数見られた。【結語】当院放射線科研修において，初期研修医が救急疾患画像や各必修研修科での臨床診療に即した読影研修を希望している実態が明らかとなった。今後の当センター放射線科の研修においては，本調査結果で明らかとなったニーズに適した研修内容の充実が望まれる。