Traumatic hematomas of the adrenal glands: CT and US findings in 3 cases

Traumatic hematomas of the adrenal gland are but little known; they are but seldom discussed in literature, and can be demonstrated only by US and CT due to their small size. These lesions are mostly located on the right side, probably following a direct trauma of the adrenal parenchyma against vertebral bodies, or as a result of the rupture of medullary sinusoids for a sharp rise in pressure into the inferior vena cava, during trauma. Bilateral traumatic hematomas can cause severe adrenal failure, and the healing is slow, without calcifications, and takes several months. Three new cases are reported, unilateral on the right adrenal bed. In 2 patients CT demonstrated a slight parenchymal enlargement after thoraco-abdominal traumas; the patients were young and healthy, and the lesions completely disappeared in some years. US detected a third hematoma in a young woman with suspected metastasis from ovarian carcinoma: CT confirmed the parenchymal swelling, and a percutaneous transhepatic biopsy clarified the diagnosis. Adrenal hematomas are to be reported in order to avoid confusing them with neoplastic lesions, even though only percutaneous biopsy allows a quick and reliable diagnosis.     

肾上腺创伤的CT表现

目的 探讨肾上腺损伤(AGT)的CT表现特征.方法 回顾性分析1712例因腹部钝伤行CT检查的患者中AGT患者的CT检查结果.结果 1712例中,共发现AGT 29例(1.7%),右侧损伤23例,左侧3例,双侧3例,共32个病灶.主要CT表现:(1)肾上腺血肿:22例25个病灶,呈孤立立圆形或卵圆形肿块,平扫为高密度或混杂密度,三期动态增强扫描均无强化,肿块周围见推移张开的肾上腺肢体,呈弧形线状明显强化.(2)肾上腺肿胀:4例,表现为受损部肾上腺肢体肿胀,体积增大.(3)肾上腺弥漫性出血:3例,肾上腺被出血包埋,正常肾上腺结构消失.1例伴对比剂外溢,手术证实为肾上腺碎裂伴活动性出血.伴随征象主要包括伤侧肾上腺周围条纹状出血浸润影,膈肌脚增粗等.合并其他胸腹部脏器损伤25例.结论 AGT具有特征性CT表现,采用合理扫描技术并正确认识AGT的CT征象有助于避免漏诊和误诊.     

Right adrenal hematoma following hepatectomy

We present the findings and possible causes in three cases of postoperative adrenal hematomas. In 16 cases of 45 consecutive patients, following segmental right or left lobe hepatectomy, CT was performed in order to evaluate possible fluid collection or other complications. In all cases imaging findings and a correlation with preoperative CT scans were done. Follow-up CT examinations were also reviewed. In three cases solid suprarenal masses with attenuation values consistent with adrenal hematomas were found. Preoperative scans at the same level indicated normal adrenal glands. Follow-up scans revealed the hematoma, stable in size, for up to 12 weeks, although lower attenuation values were evident. Right adrenal hematoma is a possible postoperative complication following hepatectomy; if it remains stable in size, it can be left alone. Received: 29 December 1998; Revised: 25 March 1999; Accepted: 18 May 1999     

外伤性肾上腺血肿CT诊断

目的：探讨外伤性肾上腺血肿的CT影像学诊断价值方法9例因外伤致肾上腺血肿患，分别于1周、1月内、1月以上至6个月追踪随访CT扫描，进行对比分析。结果：血肿早期即1周内病变平扫呈均匀的圆形或椭圆形稍高密度灶，增强扫描无强化，其中有4例见残留正常肾上腺组织且强化明显，血肿1周以上至1个月，血肿均有不同程度缩小、全部病例血肿密度不均，呈厚环状强化；血肿吸收及囊变期1个月至6个月内，大部血肿显示机化缩小为强化明显的结节状，部分吸收消失，少数囊变。结论：外伤性肾上腺血肿各个时期CT有一定特征性，动态随访扫描可对其诊断与鉴别诊断提供可靠依据。     

高场MRI在闭合性脾损伤诊断中的应用价值

 目的 探讨高场1.5T MRI在闭合性脾损伤诊断中的应用价值。方法 回顾性分析经病理或随诊证实54例闭合性脾损伤患者的1.5T MRI图像信息,并与首诊CT图像相比较,确定脾内血肿及脾被膜血肿为直接诊断征象,脾内密度或信号不均、体积增大、边缘毛糙、腹腔积血为间接诊断征象,分析比较MRI及CT两种影像方法在发现直接与间接征象个数上的差异性。结果 54例脾损伤中,首诊CT确诊46例,疑似5例,3例漏诊;首诊MRI确诊51例,疑似3例,无漏诊。MRI发现脾内血肿个数高于CT,脾被膜血肿、间接征象的发现个数低于CT,差异具有统计学意义(P＜0.05)。结论 MRI脾损伤影像特点具有特征性,在部分隐匿性病例中能够与CT检查互为补充,为临床及时诊治提供重要的参考价值。     

Low-density pheochromocytoma on CT: a mimicker of adrenal adenoma

OBJECTIVE: Attenuation values on CT of less than 10 H are considered characteristic of adrenal adenomas. Adrenal pheochromocytomas can infrequently contain fat that could result in low attenuation on CT. The purpose of our study was to determine if pheochromocytomas could be confused with adenomas by virtue of their attenuation values on unenhanced CT. MATERIALS AND METHODS: CT attenuation and size of nine adrenal nodules producing pheochromocytoma syndrome were measured on unenhanced CT in nine patients. For five patients who received IV contrast material, washout profiles were also calculated. RESULTS: Two of the nine patients had adrenal lesions with attenuation values of less than 10 H; one had a pheochromocytoma with an attentuation of 9.0 H, and the other had a medullary hyperplasia with an attenuation of 1.8 H. These two nodules showed evidence of microscopic fat at histologic examination. No macroscopic fat was seen on the CT scans. The remaining seven patients had lesions with attenuation values exceeding 10 H (mean value, 25.6 H; range, 1.8-41 H). Mean diameter of the nine tumors (including the hyperplastic nodule) was 3.2 cm (range, 0.8-6.7 cm; SD, +/- 2.3 cm). The two low-attenuation lesions also mimicked adenomas by displaying more than 60% contrast washout on 10-min-delayed contrast-enhanced scans, unlike the other three pheochromocytomas for which we had washout data. CONCLUSION: On CT, pheochromocytomas may have attenuation values less than 10 H and also may display more than 60% washout of contrast agents on delayed scanning. Adrenal pheochromocytomas should be included with adenomas in the differential diagnosis both for masses with low attenuation on unenhanced CT and for lesions exhibiting a high percentage of contrast washout.     

Limitations of computerized tomography in diagnosis of subdural hematoma

Summary CT findings in 51 patients with subdural hematomas are studied. Direct signs (hyperdensity, hypodensity) and indirect signs (any form of mass lesion) are distinguished. CT is limited with regard to determining correlations between time and the attenuation values. The factors which influence density of the hematoma are discussed. For a rational approach with subdural hematomas, which present diagnostic problems and reveal the limitations of CT diagnosis, a diagnostic scheme is proposed.     

钝性肾上腺损伤的MSCT表现特征

目的探讨钝性肾上腺损伤(blunt adrenal gland trauma,BAGT)特征性多层螺旋CT(MSCT)表现。资料与方法回顾性分析经手术或临床随访证实的40例BAGT患者的MSCT平扫和动态增强的影像资料。采用GELightspeed多排螺旋CT机,运用薄层小螺距扫描和最大密度投影(MIP)与多平面重组(MPR)技术。结果 40例中,右侧33例,左侧6例,双侧1例。BAGT主要征象:(1)肾上腺血肿29例,MSCT像上呈圆形、卵圆形高密度血肿,三期增强扫描血肿无强化,其周围可见受压推移并张开的人字形、弧线状强化的肾上腺肢体影。(2)肾上腺肿胀8例,MSCT表现为损伤的肾上腺肿胀增粗,但仍保持线状或人字形的肾上腺基本外形,三期增强扫描肿胀的肾上腺强化密度减低。(3)肾上腺碎裂3例,肾上腺变形、碎裂,密度混杂,并被血肿淹没。(4)对比剂外溢2例,增强动脉期损伤的肾上腺肢体可见点状溢出的高密度对比剂影;门静脉期与延迟期呈糊状、结节状高密度,范围扩大。MPR、MIP重组清楚地显示肾上腺肿胀、血肿、碎裂、对比剂外溢征象。结论 BAGT具有特征性CT表现,MSCT动态增强与后处理技术能清楚地显示其各种病理改...     

Adrenal masses: CT characterization with histogram analysis method

PURPOSE: To evaluate a histogram analysis method for differentiating adrenal adenoma from metastasis at computed tomography (CT). MATERIALS AND METHODS: In a retrospective review of 2 years of clinical CT records, 223 adrenal adenomas in 193 patients (115 with contrast material-enhanced CT, 43 with unenhanced and enhanced CT, and 35 with unenhanced CT) and 31 metastases (25 patients with enhanced CT) were found. In 158 patients with adenomas at enhanced CT, diagnosis was based on stable mass size for more than 1 year (n = 135) and characteristic signal intensity decrease at chemical shift magnetic resonance imaging (n = 23). In 35 patients with adenomas at unenhanced CT, mean attenuation was 10 HU or less. Diagnosis of all metastases was based on rapid growth of a mass or new mass in less than 6 months in patients with cancer. Adrenal metastases with extensive necrosis were excluded. Histogram analysis was performed in a circular region of interest (ROI) for mean attenuation, number of pixels, and range of pixel attenuation for all pixels and for the subset of pixels with less than 0 HU ("negative" pixels). Correlation between mean attenuation and percentage negative pixels was calculated. RESULTS: Negative pixels were present in all 74 unenhanced adenomas with mean attenuation of 10 HU or less and in 14 of 16 unenhanced adenomas with mean attenuation above 10 HU. Of 184 enhanced adenomas, only 20 had mean attenuation of 10 HU or less, but 97 contained negative pixels (77 of these 97 masses had mean attenuation above 10 HU). Increase in percentage negative pixels was highly correlated with decrease in mean attenuation of both unenhanced and enhanced adenomas. None of the adrenal metastases had mean attenuation of 10 HU or less or contained negative pixels. CONCLUSION: The histogram method is far more sensitive than the 10-HU threshold method for diagnosis of adrenal adenomas at enhanced CT, with specificity maintained at 100%.     

Role of multidetector row computed tomography in the assessment of adrenal gland injuries

OBJECTIVE: To determine the prevalence of adrenal injuries in a group of patients submitted to multidetector row CT evaluation after blunt trauma and to assess the impact of CT findings on clinical management decisions. MATERIALS AND METHOD: During a 4-year period, 2026 emergency CT examinations were performed in the setting of major blunt trauma. A total of 82 patients were retrospectively identified as having adrenal gland traumatic lesions. At multidetector row CT the following findings were considered specific of adrenal injury: round or oval hematoma expanding the adrenal gland, irregular hemorrhage obliterating the gland, uniform adrenal gland swelling, active extravasation of contrast material from the adrenal vessels and adrenal gland rupture. Associated CT findings were: stranding of the periadrenal fat, diffuse hemorrhage in the adjacent retroperitoneum and compression of the adrenal gland by adjacent traumatic lesions. RESULTS: We identified 82 patients (46 males and 36 females, age ranging from 15 to 86 years) with adrenal injuries. The right adrenal gland was injured in 60/82 patients, while the left adrenal gland was injured in 21 cases; in 1 patient bilateral adrenal gland traumatic lesions occurred. In 76 patients with non-isolated adrenal injuries concomitant injuries to the liver (49 cases), ipsilateral kidney (18 cases) and spleen (9 cases) were observed. Round or oval hematoma expanding the adrenal gland (61 cases), irregular hemorrhage obliterating the gland (14 cases), stranding of the periadrenal fat (9 cases) and diffuse hemorrhage in the adjacent retroperitoneum (8 cases) were the more frequent findings detected at CT. Six patients underwent surgical intervention for the presence of major injuries to the spleen (three cases), to the liver (one), to the right kidney (one), to the left kidney (one). Seventy-six patients were conservatively treated. CONCLUSION: Blunt adrenal injuries typically present as part of a multiorgan trauma. Familiarity with characteristic CT findings of adrenal trauma is essential for the radiologist to avoid misdiagnosis.     

Differentiating adrenal adenomas from nonadenomas using (18)F-FDG PET/CT: quantitative and qualitative evaluation

RATIONALE AND OBJECTIVES: We sought to assess the ability of (18)F-fluoro-2-deoxy-d-glucose (FDG) PET/CT to distinguish adrenal adenomas from nonadenomas in patients with suspected malignancy. METHODS: Fifty-nine adrenal masses were evaluated with coregistered (18)F-FDG PET (PET/CT). Two reviewers independently graded uptake of (18)F-FDG by visual inspection of the adrenal mass in comparison to liver and background. CT attenuation value of the adrenal mass and the standardized uptake value (SUV) of the mass, liver, background, and primary neoplasm (when visible) were measured. Mean SUVs of the adrenal mass, liver, and background and ratios of the SUVs were calculated. RESULTS: Of 47 adenomas, 43 measured <10 HU on unenhanced CT. Of 12, 12 nonadenomas measured >10 HU on unenhanced CT. Using qualitative assessment of FDG activity in the adrenal mass compared with liver, adenomas were less than, equal to, or more active than the liver in 51%, 38%, and 10%, respectively. Nonadenomas were less than, equal to, or more active than liver in 0%, 25%, and 75%, respectively. The mean SUV of adenomas (4.2) was significantly lower (P = .002) than that of their primary malignancies (9.2) but not that of liver (4.3). The mean SUV of adenomas was not significantly different than that of nonadenomas (5.2), but the mean adrenal/liver ratio (1.0) for the adenomas was significantly lower (P = .006) than that of the nonadenomas (2.1). CONCLUSION: Adrenal adenomas were better differentiated from nonadenomas using unenhanced CT measurements in combination with ratios of the SUVs. Adrenal mass activity, which was visibly less than liver, was more specific for adenoma, whereas adrenal mass activity visibly greater than liver was more specific for malignancy.     

Adrenal hemorrhage after liver transplantation

During orthotopic liver transplantation, ligation and division of the right adrenal vein during recipient hepatectomy may lead to hemorrhagic infarction and/or hematoma formation in the right adrenal gland. Findings in seven liver transplant recipients included initially echogenic or anechoic suprarenal masses on ultrasound scans and inhomogeneous but predominantly hypoattenuating masses on computed tomographic scans. In patients who survived for 4 months or longer, hematomas resolved as early as 20 days and persisted as long as 11 weeks. There was autopsy proof of adrenal hemorrhage in three cases. The adrenal hematomas in this series produced no massive hemorrhages, adrenal insufficiency, or other clinical manifestations. Adrenal hemorrhage after liver transplantation should be recognized and specifically documented, but a hematoma that remains stable in size can be left alone.     

CT manifestations of adrenal trauma: experience with 73 cases

Adrenal injuries, although an uncommon consequence of abdominal trauma, are important to recognize. If bilateral, adrenal trauma could result in life-threatening adrenal insufficiency. Furthermore, in the setting of trauma, adrenal injury can point to other concomitant injuries and has been associated with overall increased morbidity and mortality. In the past, before the advent of computed tomography (CT), detection was difficult, and the diagnosis was often made only at surgery or postmortem. Today, the diagnosis of adrenal injuries can be quickly and accurately made with CT. This retrospective review was carried out to identify, describe, and analyze different CT appearances of adrenal injuries and correlated with associated injuries and observed clinical context and outcomes. A patient cohort of CT-detected adrenal injuries was identified through a radiology software research tool by searching for keywords in radiology reports. The identified CT scans were reviewed and correlated with the patients’ available clinical chart data and follow-up. Between April 1995 and October 2004, 73 cases of CT-detected adrenal injuries were identified, including 48 men and 25 women, with an age range 6 to 90 years and a mean age of 42.7 years. Of the cases, 77% were right-sided, 15% were left-sided, and 8% were bilateral. The causes of injuries were motor vehicle collisions (75%), falls (14%), sports related (4%), and miscellaneous causes (7%). Associated trauma included injuries of the liver (43%), spleen (23%), lung (19%), and kidney (18%), as well as pneumothoraces/hemothoraces (22%). Skeletal injuries included fractures of the ribs, clavicles, and/or scapulae (39%), pelvis and hips (30%), and the spine (23%). Isolated adrenal trauma was seen in only 4% of the cases. The CT findings of adrenal trauma were focal hematoma (30%), indistinct (27%) or enlarged (18%) adrenal gland, gross (15%) or focal (7%) adrenal hemorrhage, and adrenal mass (11%). Associated CT findings included periadrenal fat stranding (93%), retroperitoneal hemorrhage (22%), and thickened diaphragmatic crura (10%). Active adrenal bleeding was seen in one case (1.4%). The incidence of adrenal trauma was estimated to be 0.86%. Surgical management was required only for the associated injuries. The most common CT manifestations of adrenal trauma include focal hematoma, indistinct or ill-defined adrenal gland, adrenal enlargement or mass, and gross or focal adrenal hemorrhage in a normal-sized gland. Periadrenal stranding is very common. Retroperitoneal hemorrhage and crural thickening are also important associated findings. Operative intervention is typically required only for the associated injuries, which commonly accompany adrenal trauma. This original research article was presented at RSNA 2005.     

Primary hyperaldosteronism: comparison of CT, adrenal venography, and venous sampling

Twenty-nine patients with primary hyperaldosteronism were evaluated with computed tomography (CT), adrenal venous sampling, and adrenal venography. Twenty-three patients had aldosteronomas and six had bilateral adrenocortical hyperplasia. Sixteen (70%) of the adenomas were accurately located by CT. All nodules of 1.5 cm or larger diameter and 50% of nodules 1.0-1.4 cm in diameter were demonstrated. Nodules of less than 1.0 cm in diameter generally were not detected. High-resolution CT appeared more sensitive than standard CT (75% vs. 58%). Adrenal venous sampling for aldosterone assay was the most sensitive of the three methods, localizing 22 (96%) of the 23 adenomas. Eighteen (78%) of the adenomas were identified by adrenal venography, although two patients with bilateral cortical hyperplasia were mistakenly diagnosed as having a small adenoma. No such false-positive studies were encountered with CT or adrenal venous sampling.     

CT of bilateral adrenal hemorrhage with acute adrenal insufficiency in the adult

Bilateral adrenal hemorrhage and acute adrenal insufficiency in three acutely ill patients occurred as a complication of pneumonia in two and recent abdominal surgery in the third. The diagnosis was unsuspected in each case before abdominal computed tomography (CT), which showed bilateral adrenal masses. CT was done for suspected intraabdominal sepsis. Adrenal insufficiency was confirmed by endocrine studies, and each patient promptly recovered with steroid replacement therapy. Follow-up CT showed diminution or disappearance of the masses and density changes consistent with resolving hematomas.     

CT of the adrenal gland: the many faces of adrenal hemorrhage

Adrenal hemorrhage is rarely suspected clinically, exhibits no specific clinical symptoms or laboratory findings, and yet is immediately life-threatening when bilateral. Recognition of adrenal hematomas is complicated by the variable appearance of these lesions. We survey the ways in which adrenal hematomas can appear on CT and provide strategies for differentiating hematomas from other adrenal pathologies.     

肾上腺结核的增强CT表现特征与临床病程的相关性

目的探讨肾上腺结核的增强CT表现特征与临床病程的相关性，以提高该病的影像诊断水平。方法经临床证实的肾上腺结核30例，在CT强化图像上观察肾上腺的位置、大小、形态、密度以及强化特征，并结合临床和病理资料加以分析，采用Cochran Armitage趋势检验进行统计分析。结果肾上腺结核累及双侧共27例（90．0％），单侧3例（10．0％）。肾上腺肿块样增大13例，轻度或中度增大17例，轮廓仍保持完整。肾上腺增大密度均匀2例（6．7％），不均匀增大28例（93．3％）。周边强化16例（53．3％），钙化17例（56．7％）。经抗结核治疗后的6例复查CT示，5例双侧增大的肾上腺体积缩小或恢复正常，其内低密度消失，新出现点状钙化2例。钙化多见于临床后期，17例钙化中，病程〉12个月者10例，存在随病程增长而递增的分布趋势（x^2=7．47，P〈0．05），而周边强化则多见于临床早期，16例中有11例临床病程≤12个月，存在随病程增长而递减的分布趋势（x^2=6．60，P〈0．05）。结论肾上腺结核CT具有特征性表现，与临床病程存在一定的相关性，为临床治疗及疗效判断提供指导。     

Can single-phase dual-energy CT reliably identify adrenal adenomas?

Purpose

To evaluate whether single-phase dual-energy-CT-based attenuation measurements can reliably differentiate lipid-rich adrenal adenomas from malignant adrenal lesions.

Materials and methods

We retrospectively identified 51 patients with adrenal masses who had undergone contrast-enhanced dual-energy-CT (140/100 or 140/80 kVp). Virtual non-contrast and colour-coded iodine images were generated, allowing for measurement of pre- and post-contrast density on a single-phase acquisition. Adrenal adenoma was diagnosed if density on virtual non-contrast images was ≤10 HU. Clinical follow-up, true non-contrast CT, PET/CT, in- and opposed-phase MRI, and histopathology served as the standard of reference.

Results

Based on the standard of reference, 46/57 (80.7 %) adrenal masses were characterised as adenomas or other benign lesions; 9 malignant lesions were detected. Based on a cutoff value of 10 HU, virtual non-contrast images allowed for correct identification of adrenal adenomas in 33 of 46 (71 %), whereas 13/46 (28 %) adrenal adenomas were lipid poor with a density ≥10 HU. Based on the threshold of 10 HU on the virtual non-contrast images, the sensitivity, specificity, and accuracy for detection of benign adrenal lesions was 73 %, 100 %, and 81 % respectively.

Conclusion

Virtual non-contrast images derived from dual-energy-CT allow for accurate characterisation of lipid-rich adrenal adenomas and can help to avoid additional follow-up imaging.

Key Points

? Adrenal adenomas are a common lesion of the adrenal glands. ? Differentiation of benign adrenal adenomas from malignant adrenal lesions is important. ? Dual-energy based virtual non-contrast images help to evaluate patients with adrenal adenomas.     

肾上腺损伤的CT诊断

目的: 探讨肾上腺损伤的CT表现及其诊断价值.材料和方法: 回顾性分析经手术或CT随访证实的9例肾上腺损伤的CT表现.结果: 单侧肾上腺损伤7例(右侧6例,左侧1例),双侧肾上腺损伤2例.肾上腺损伤肿胀型2例,表现为肾上腺体积增大,密度增高;肾上腺血肿形成7例.肾周脂肪内出现条纹状出血影6例;膈脚增粗5 例;合并其他脏器损伤8例.结论: CT,尤其是多排螺旋CT能准确显示肾上腺损伤的多种病理解剖改变,对肾上腺损伤的诊断具有重要价值.     

Subdural hematomas in infants with benign enlargement of the subarachnoid spaces are not pathognomonic for child abuse

BACKGROUND AND PURPOSE: Patients who have benign enlargement of the subarachnoid spaces (BESS) have long been suspected of having an increased propensity for subdural hematomas either spontaneously or as a result of accidental injury. Subdural hematomas in infants are often equated with nonaccidental trauma (NAT). A better understanding of the clinical and imaging characteristics of subdural hematomas that occur either spontaneously or as a result of accidental trauma may help distinguish this group of patients from those who suffer subdural hematomas as a result of NAT. The purpose of this study is to describe the clinical and imaging characteristics of subdural hematomas that occur either spontaneously or as a result of accidental injury in infants with BESS. METHODS: We conducted a retrospective review of all patients with BESS complicated by subdural hematomas evaluated at a single institution from 1998 to 2004. Data concerning the patient's clinical presentation, physical findings, imaging, and management are described. RESULTS: During the study period, 7 patients with BESS complicated by subdural hematoma were identified. Their mean age at identification of the subdural hematoma was 7.4 months of age. In 5 cases, there was no recognized trauma before identification of the subdural hematoma. In 3 cases, baseline CT or MR imaging was available, showing prominent subarachnoid spaces without any evidence of subdural hemorrhage. CONCLUSION: Although suspicious for NAT, subdural hematomas can occur in children either spontaneously or as a result of accidental trauma. Caution must be exercised when investigating for NAT based on the sole presence of subdural hematomas, especially in children who are otherwise well and who have BESS.