Necrotizing soft tissue infections of the body wall: Computed tomographic evaluation

The spectrum of soft tissue infection ranges from cellulitis to uncommon, but potentially fatal, diseases like necrotizing fasciitis and myonecrosis. The severity and extent of infection can be difficult to assess by physical examination alone. Computed tomography can accurately define the location and extent of infection as well as aid in its characterization. This information is critical in guiding surgical intervention in necrotizing soft tissue infections, which have a high mortality rate and require early recognition and aggressive surgical debridement. The presence of soft tissue gas or the involvement of deep fascia is highly suggestive of severe necrotizing soft tissue infection. We describe the computed tomographic appearance of three cases of necrotizing infection involving the fascia and muscles of the body wall.     

A case report of Fournier's gangrene: Imaging ultrasound and computed tomography (CT) scan

Necrotizing fasciitis and/or Fournier''s Gangrene is a rare, life-threatening soft tissue infection that, if not treated promptly, can immediately develop into systemic toxicity. It affects the genital, perineal, and perineal tissues, predominantly affecting men but can be seen in women. The diagnosis is often made clinically but radiologic examinations are helpful to determine the extent of the infection and can aid preoperative planning. Treatment consists of immediate and aggressive surgical debridement of necrotized tissue, broad-spectrum antibiotics, and early resuscitation. Here, we present a 56-year-old male patient with Fournier''s gangrene and describe the physical examination, bedside sonographic, and computed tomography findings. These findings can aid in the evaluation of patients with worrying symptoms so that antibiotics can be administered immediately and specialists can be consulted as needed.     

Magnetic resonance imaging of soft tissue tumors

This article outlines the ability of MR imaging in staging, grading, tissue characterization, and posttherapeutic surveillance of soft tissue tumors. Well-known staging parameters, such as extent, relationship with adjacent structures, and detection of intralesional necrosis, are used in the MR protocol for locoregional staging. Bone scintigraphy and high-resolution CT scan of the lungs are best methods for ruling out metastatic spread. A variety of (solitary or combinations of) grading parameters are described in the radiological literature. The role of MR imaging is to afford recognition of these lesions that need further aggressive work-up, excluding all others. Despite controversial reports, the definite role of MR imaging in grading of soft tissue tumors seems to become established. As for grading, a lot of individual imaging characteristics used for tissue characterization have low sensitivity, but combinations of parameters (age, site, signal intensities) are more useful and often allow to predict a specific diagnosis or to narrow down the list of differential diagnoses. Local recurrences of soft tissue tumors are frequent and can be detected accurately by an easy-to-use MR algorithm.     

18F-FDG PET/CT对下肢开放骨折术后感染的定位诊断价值及引导作用

 目的 评价¹⁸F-FDG PET/CT对下肢开放骨折术后感染的定位诊断价值及对清创术的引导作用。方法 收集医院2018-07至2019-06收治的15例下肢外伤骨折术后可疑慢性局部感染患者资料,清创术前1周内接受¹⁸F-FDG PET/CT检查;根据PET/CT影像定位感染灶,并与术后病理、微生物培养结果及PET/CT对照;分别计算骨感染灶和软组织感染灶的平均SUV_max,并与1例SPECT/CT骨显像进行对比分析;评价PET/CT引导下清创术的效果。结果 15例中6例为单纯骨感染灶,3例为单纯软组织感染灶,6例同时存在骨感染灶及软组织感染灶;PET/CT共发现骨感染灶18处,软组织感染灶12处,其中骨感染灶SUV_max为5.1±3.4,软组织感染灶SUV_max为3.6±2.4;PET/CT对骨感染灶的诊断灵敏性为94.4%,对软组织感染灶的诊断灵敏性为83.3%;PET/CT诊断灵敏性高于SPECT/CT骨显像;经PET/CT引导下的一次清创治愈率为93.3%(14/15)。结论 ¹⁸F-FDG PET/CT诊断下肢开放骨折术后感染的准确性高,引导手术清创效果可靠。     

CT diagnosis of cardiac and pericardial injuries

The purpose of this retrospective study was to determine the CT findings diagnostic of cardiac and pericardial injury, including signs of pericardial tamponade, in patients suffering from blunt and penetrating trauma. A search of the CT radiology database at a level I trauma center was performed to identify cases in which injury to the heart or pericardium was diagnosed, as well as to identify cases of pericardial tamponade. All cases were reviewed to ascertain the specific CT findings, and medical records were reviewed to assess the influence of CT findings on management and to assess for clinical evidence of pericardial tamponade. Eighteen patients had direct CT evidence of cardiac or pericardial injury, including nine cases of pneumopericardium, eight cases of hemopericardium, and one case of intrapericardial gastric herniation. Four of these patients were found to have direct cardiac injuries. Three additional cases with CT evidence of pericardial tamponade were identified, two secondary to cardiac compression by an anterior mediastinal hematoma and one following repair of left ventricular rupture. Of 11 patients with CT evidence of tamponade, only three were suspected clinically. Cardiac and pericardial injuries are usually diagnosed surgically and are often clinically unsuspected, particularly in blunt trauma. As CT is increasingly utilized as a general screening test for thoracic/abdominal trauma, these injuries may be first suspected on the basis of CT findings, and knowledge of the CT findings of cardiac injury or tamponade is crucial.     

Soft tissue and joint infection

Soft tissue infection may be acute or chronic and may be introduced by the haematogenous route, or by inoculation, including surgical infection, or spread from other areas. The spectrum of infecting organism differs in primary infection, in immunodeficiency or when foreign bodies, including prostheses, are present. Bacterial infections are usually more rapid than those due to fungi or atypical organisms. Inflammation usually begins as cellulitis, proceeding through necrosis to cavitation and abscess formation, sometimes complicated by haemorrhage. Imaging, apart from MRI in selected cases, is rarely helpful in the early stages, but early diagnosis of pyomyositis and necrotizing fasciitis is mandatory. When infection is established, US, CT and MRI all have individual value in diagnosis, including biopsy, and in directing therapy, including percutaneous or surgical drainage or debridement. Both MRI and CT are best suited to monitoring progress. Septic arthritis presents as rapidly progressive, destructive arthritis, and early diagnosis is essential to prevent long-term morbidity. Ultrasound offers the best method of detecting early joint effusion and synovial thickening, but aspiration is usually required for diagnosis. In more advanced stages CT is valuable for revealing destructive changes, and MRI for documenting intra-articular changes and detecting inflammation in surrounding bone.     

Soft tissue and joint infection

Soft tissue infection may be acute or chronic and may be introduced by the haematogenous route, or by inoculation, including surgical infection, or spread from other areas. The spectrum of infecting organism differs in primary infection, in immunodeficiency or when foreign bodies, including prostheses, are present. Bacterial infections are usually more rapid than those due to fungi or atypical organisms. Inflammation usually begins as cellulitis, proceeding through necrosis to cavitation and abscess formation, sometimes complicated by haemorrhage. Imaging, apart from MRI in selected cases, is rarely helpful in the early stages, but early diagnosis of pyomyositis and necrotizing fasciitis is mandatory. When infection is established, US, CT and MRI all have individual value in diagnosis, including biopsy, and in directing therapy, including percutaneous or surgical drainage or debridement. Both MRI and CT are best suited to monitoring progress. Septic arthritis presents as rapidly progressive, destructive arthritis, and early diagnosis is essential to prevent long-term morbidity. Ultrasound offers the best method of detecting early joint effusion and synovial thickening, but aspiration is usually required for diagnosis. In more advanced stages CT is valuable for revealing destructive changes, and MRI for documenting intra-articular changes and detecting inflammation in surrounding bone.     

Rheumatoid arthritis of the craniocervical region: assessment and characterization of inflammatory soft tissue proliferations with unenhanced and contrast-enhanced CT

The aim of this study was to depict and characterize inflammatory soft tissue proliferations caused by rheumatoid arthritis (RA) in the craniocervical region by unenhanced and contrast-enhanced CT. Computed tomography of the craniocervical region was performed in 35 patients in the axial plane before and after the i. v. administration of contrast material. According to the densities and contrast enhancement of the inflammatory soft tissue proliferations, four groups were classified. Ancillary findings, such as a compression of the dural sac or spinal cord, erosions of the bony structures, and atlantoaxial subluxation, were also evaluated. Inflammatory soft tissue proliferations were depicted in 28 of 35 patients and could be differentiated by unenhanced and contrast-enhanced CT according to the above defined criteria: effusion in 6 patients (17 %); hypervascular pannus in 8 (23 %); hypovascular pannus in 5 (14 %); and fibrous tissue in 9 patients (26 %). A compression of the dural sac was seen in 11 (31 %) patients; 3 of these had neurological symptoms. Erosions of the odontoid process were found in 20 (57 %) patients; 16 (80 %) of these also showed erosions of the atlas. Atlantoaxial subluxation was seen in 11 (31 %) patients. Inflammatory soft tissue proliferations in the craniocervical region caused by RA can be reliably demonstrated and classified by unenhanced and contrast-enhanced CT, which can differentiate between joint effusion and various forms of pannus and depict ancillary findings. Computed tomography is an alternative method for patients unable to undergo an MRI examination. Received: 4 October 1999; Revised: 7 March 2000; Accepted: 14 March 2000     

Mediastinal myelolipoma: CT and MRI appearances

A 72-year-old man presented with a mediastinal mass on chest radiograph. Computed tomography and MR imaging showed that the mass consisted of both fatty and small nodular soft tissue components, highly suggestive of an extramedullary hematopoiesis or a myelolipoma. A CT-guided needle biopsy was next performed and confirmed the diagnosis. We discuss the CT and MR imaging appearances of this tumor and usefulness of a CT-guided needle biopsy to avoid surgery in asymptomatic patients. Received: 8 March 1999; Revised: 23 June 1999; Accepted: 25 June 1999     

Evaluation of CT findings for diagnosis of pleural effusions

Computed tomography studies are usually used to assess patients with pleural effusions, and radiologists should be aware of the significance of different CT findings for the diagnosis of the effusion. The purpose of this study was to evaluate CT findings for etiological diagnosis of pleural effusions. Contrast-enhanced CT of the chest of 211 patients with pleural effusion of definite diagnosis were evaluated. The CT images were evaluated for the presence and extent of pleural effusion, thickening or nodules, extrapleural fat and other changes in the mediastinum or lung. The CT scans were read by two independent observers and correlation between them was evaluated. Comparison of CT findings between benign and malignant effusions, between exudates and transudates, and between empyemas and the other parapneumonic effusions were carried out. Kappa values for most CT findings were > 0.85. Loculation, pleural thickening, pleural nodules, and extrapleural fat of increased density were only present in exudative effusions. Multiple pleural nodules and nodular pleural thickening were the only pleural findings limited to malignant pleural effusions. The signs were also more frequently seen in empyemas than in other parapneumonic effusions. Computed tomography findings can help to distinguish between transudates and exudates. Although there is some overlap between benign and malignant pleural effusions, pleural nodules and nodular pleural thickening were present almost exclusively in the latter. Although differences between CT findings of empyemas and the other parapneumonic effusions exist, there is no finding which can definitely differentiate between them. Received: 27 January 1999; Revised: 24 June 1999; Accepted: 24 August 1999     

Spontaneous suburothelial hemorrhage in coagulopathic patients: CT diagnosis

OBJECTIVE: The objective of our study was to identify and describe the spectrum of CT findings in patients with coagulopathy-induced suburothelial hemorrhage involving the renal collecting system. CONCLUSION: CT findings of suburothelial hemorrhage are often subtle and are best appreciated on unenhanced CT scans because of the high density of the hemorrhage. After contrast injection, uniformly thickened soft tissue enveloping the collecting system is suggestive of this condition. Clinical information regarding the presence of coagulopathy is essential for the radiologist to entertain this relatively rare diagnosis.     

Necrotizing fasciitis of soft tissues: role of diagnostic imaging and review of the literature

PURPOSE: We retrospectively reviewed the diagnostic imaging findings (radiography, CT and US) of our cases of necrotizing fascitis of soft tissues looking for signs that could be useful for early and accurate diagnosis. MATERIAL AND METHODS: May 1991 to February 1998 we examined 130 patients with progressive necrotizing soft tissue infections; in 32 of them (22-84 years old) the retrospective pathologic diagnosis was necrotizing fascitis. Involved sites were the limbs (26/32), the cervical region (5/32) and the perineal region (1/32). Nineteen patients were submitted to conventional radiography, also for soft tissue studies. US was performed in an emergency setting in all the 32 cases, by a selected group of US operators particularly skilled in this kind of soft tissue condition. Contrast enhanced CT was performed in 9 cases. RESULTS: B-mode and Doppler US yielded useful and reliable information for prompt and correct diagnosis. Particularly these techniques showed changes in subcutaneous adipose tissue (28/32), fascia (18/32) and muscle (15/32). We found a good correlation between tissue changes as shown at US and histologic findings, but US missed changes in subcutaneous soft tissue and muscle in 11 cases (3/32 and 8/32, respectively) with subsequent histologic confirmation. Contrast enhanced CT better defined the extent of disease and possible complications, especially in sites that are difficult to study with US. DISCUSSION AND CONCLUSIONS: Early diagnosis and proper treatment are the key issues affecting the chances of recovery for patients with necrotizing fascitis. The clinical suspicion of this condition calls for prompt intervention with effective diagnostic protocols. B-mode, and sometimes color Doppler, US and contrast enhanced CT, together with appropriate laboratory tests, can provide useful information for precise diagnosis and proper treatment.     

Penetrating trauma to the abdominal aorta: CT demonstration of active bleeding

Contrast-enhanced helical computed tomography (CT) is the imaging study of choice for evaluating the abdomen in hemodynamically stable patients following blunt trauma. Surviving victims of penetrating trauma, in contrast, are often hemodynamically unstable and may require urgent celiotomy with or without diagnostic peritoneal lavage (DPL) or ultrasonography. Abdominal CT is not routinely performed in this patient population, but may be done if the patient with penetrating abdominal trauma is stable on admission or becomes so with resuscitation. CT in this context can address questions regarding the location and extent of injury and help decide appropriate management. We present a case of a stabilized blunt and penetrating trauma patient with negative DPL and active retroperitoneal aortic extravasation demonstrated by CT. To our knowledge, penetrating injury to the aorta with active bleeding has not been previously seen on CT.     

CT diagnosis of diaphragm injuries

Admission supine chest radiographs are the initial and most commonly performed imaging study to evaluate the thorax following trauma. Whenever the chest radiograph is ambiguous or suggestive of a diagnosis of acute diaphragmatic injury, CT is the next study of choice since it is generally available and often used to examine other body regions of the polytraumatized patient. CT is usually diagnostic, particularly if supplemented by multiplanar reformations obtained using a thin slice thickness. Currently MR imaging is used at our trauma center to evaluate the diaphragm in patients with an indeterminate diagnosis after spiral CT. A limited MR imaging examination with T1-weighted sagittal and coronal imaging has been extremely accurate in establishing or excluding diaphragm injury.     

Imaging of chest wall infections

A wide variety of infections can affect the chest wall including pyogenic, tuberculous, fungal, and some other unusual infections. These potentially life-threatening disorders are frequent especially among immunocompromised patients but often misdiagnosed by physical examination and radiographs. The purpose of this article is to describe the clinical and imaging features of these different chest wall infections according to the different imaging modalities with emphasis on ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). The outcome of chest wall infection depends on early diagnosis, severity of the immunosuppression, offending organism, and extent of infection. Because clinical findings and laboratory tests may be not contributive in immunocompromised patients, imaging plays an important role in the early detection and precise assessment of the disease. US, CT, and MRI are all useful: bone destruction is more accurately detected with CT whereas soft tissue involvement are better visualized with US and MRI. CT and US are also used to guide percutaneous biopsy and drainage procedures. MR images are helpful in pre-operative planning of extensive chest wall infections.     

Non-Hodgkin lymphoma in skeletal muscle manifesting as homogeneous masses with CT attenuation similar to muscle

 Two cases are presented of masses in muscle due to non-Hodgkin lymphoma (NHL) that were homogeneous and isoattenuating to normal muscle on CT. In each case, the mass was clinically suspected of representing soft tissue sarcoma. However, the masses were relatively inapparent on CT, being visible predominantly as mass effect – an appearance unlike that of soft tissue sarcomas. It is important to be aware that NHL in muscle can be difficult to detect at CT, even with intravenous contrast enhancement; therefore, a clinically apparent mass should not be dismissed on the basis of an apparently unremarkable CT scan of the region. Such findings should suggest the diagnosis of NHL rather than sarcoma.     

CT, MRI and gallium SPECT in the diagnosis and treatment of petrous apicitis presenting as multiple cranial neuropathies

We present a rare case of petrous apicitis initiated by middle ear inflammation in a diabetic patient with multiple cranial neuropathies for early diagnosis of this potentially life-threatening condition. The lesion appeared as opacification of middle ear, petrous apex with aggressive bony destruction on CT and diffuse petrosal T(1) hypointensity with adjacent soft tissue propagation on MRI. Gallium-67 single-photon emission computed tomography (SPECT) scan also contributed to evaluate response to therapy.     

Emphysematous infections of the abdomen and pelvis: a pictorial review.

Emphysematous (gas-forming) infections of the abdomen and pelvis represent potentially life-threatening conditions that require aggressive medical and often surgical management. The initial clinical manifestation of these entities may be insidious, but rapid progression to sepsis will occur in the absence of early therapeutic intervention. Conventional radiography and ultrasonography are often the initial imaging modalities used to evaluate patients with abdominopelvic complaints. However, when a differential diagnosis remains, or if further localization or confirmation of tentative findings is needed, computed tomography (CT) should be considered the imaging modality of choice. CT is both highly sensitive and specific in the detection of abnormal gas and well suited to reliable depiction of the anatomic location and extent of the gas. Of equal importance may be the capability of CT to help reliably identify benign sources of gas, because treatment (if any) varies dramatically depending on the source. Knowledge of the pathophysiologic characteristics, common predisposing conditions, and typical imaging features associated with gas-forming infections of the gallbladder, stomach, pancreas, and genitourinary system will help make early diagnosis and successful treatment possible. In addition, such knowledge will aid in further diagnostic work-up, surveillance of potential complications, and evaluation of therapeutic response.     

Pancreatic clefts caused by penetrating vessels: a potential diagnostic pitfall for pancreatic fracture on CT

The diagnosis of pancreatic fracture using computerized tomography (CT) is made by identifying a linear defect in the pancreas, often with a variable amount of peripancreatic fluid. However, the fat surrounding arterial and venous vessels which penetrate the pancreas can give a very similar CT appearance – a previously unreported finding. This report describes the CT appearance of such defects as well as the macroscopic and microscopic analysis of the vessels penetrating the pancreas in a cadaver having this CT finding.