Normal CT Appearance Research Articles

Continent ileostomies: what the radiologist needs to know.

Continent ileostomies are performed in patients who are not candidates for or do not want a traditional J-pouch after total colectomy. In these cases, patients may opt for a type of continent ileostomy instead of an end ileostomy. The most common types of continent ileostomies include the Kock (K) pouch, S-pouch and Barnett Continent Intestinal Reservoir. The normal fluoroscopic and CT appearance of these types of continent ileostomies are reviewed. CT provides better evaluation of the proximal small bowel and pouch for inflammatory bowel disease, while fluoroscopy is superior in evaluating the nipple valve. Common complications of these types of continent ileostomies are discussed including slipped nipple valve, pouch inflammation, fistulas, and polyps. Radiologist should be familiar with the different types of continent ileostomies that exist and their common complications.

CT-Guided Cooled Radiofrequency Denervation for Chronic Arthritis Pain of the Hip and Shoulder.

The paradigm in the treatment of arthritis pain is shifting for previously open surgical denervations of the hip and shoulder, as it already has for the geniculate nerves in knee arthritis. Interventional radiology is poised to contribute to this space with the use of CT guidance to provide safe, fast, and effective targeting of the target nerves for unequivocal diagnostic nerve block and definitive cooled radiofrequency denervation. The authors provide the background of which nerves are targeted for hip and shoulder denervation and the normal CT appearance of these blocks.

Analysis of Chest CT Results of Coronavirus Disease 2019 (COVID-19) Patients at First Follow-Up.

Objective To investigate the dissipation and outcomes of pulmonary lesions at the first follow-up of patients who recovered from moderate and severe cases of COVID-19. Methods From January 21 to March 3, 2020, a total of 136 patients with COVID-19 were admitted to our hospital. According to inclusion and exclusion criteria, 52 patients who recovered from COVID-19 were included in this study, including 33 moderate cases and 19 severe cases. Three senior radiologists independently and retrospectively analyzed the chest CT imaging data of 52 patients at the last time of admission and the first follow-up after discharge, including primary manifestations, concomitant manifestations, and degree of residual lesion dissipation. Results At the first follow-up after discharge, 16 patients with COVID-19 recovered to normal chest CT appearance, while 36 patients still had residual pulmonary lesions, mainly including 33 cases of ground-glass opacity, 5 cases of consolidation, and 19 cases of fibrous strip shadow. The proportion of residual pulmonary lesions in severe cases (17/19) was statistically higher than in moderate cases (19/33) (χ2 = 5.759, P < 0.05). At the first follow-up, residual pulmonary lesions were dissipated to varying degrees in 47 cases, and lesions remained unchanged in 5 cases. There were no cases of increased numbers of lesions, enlargement of lesions, or appearance of new lesions. The dissipation of residual pulmonary lesions in moderate patients was statistically better than in severe patients (Z = −2.538, P < 0.05). Conclusion Clinically cured patients with COVID-19 had faster dissipation of residual pulmonary lesions after discharge, while moderate patients had better dissipation than severe patients. However, at the first follow-up, most patients still had residual pulmonary lesions, which were primarily ground-glass opacity and fibrous strip shadow. The proportion of residual pulmonary lesions was higher in severe cases of COVID-19, which required further follow-up.

Effect of a Previous History of Antiretroviral Treatment on Clinical Picture of Patients with Co-infection of SARS-CoV-2 and HIV: A Preliminary Study

ObjectivesWe aimed to explore the effect of antiretroviral treatment (ART) history on clinical characteristics of patients with co-infection of SARS-CoV-2 and HIV. MethodsWe retrospectively reviewed 20 patients with laboratory-confirmed co-infection of SARS-CoV-2 and HIV in a designated hospital. Patients were divided into medicine group (n = 12) and non-medicine group (n = 8) according to previous ART history before SARS-CoV-2 infection. ResultsThe median age was 46.5 years and 15 (75%) were female. Ten patients had initial negative RT-PCR on admission, 5 of which had normal CT appearance and 4 were asymptomatic. Lymphocytes were low in 9 patients (45%), CD4 cell count and CD4/CD8 were low in all patients. The predominant CT features in 19 patients were multiple (42%) ground-glass opacities (58%) and consolidations (32%). Erythrocyte sedimentation rate (ESR) in the medicine group was significantly lower than that in the non-medicine group [median (interquartile range, IQR):14.0 (10.0–34.0) vs. 51.0 (35.8–62.0), P = 0.005]. Nineteen patients (95%) were discharged with a median hospital stay of 30 days (IQR, 26–30). ConclusionsMost patients with SARS-CoV-2 and HIV co-infection exhibited mild to moderate symptoms. The milder extent of inflammatory response to SARS-CoV-2 infection might be associated with a previous history of ART in HIV-infected patients.

CT appearance of presumptively normal intrathoracic lymph nodes in cats.

Thoracic CT is commonly performed in cats and has been shown to be more sensitive than radiography for the detection of lymphadenopathy. However, no studies to date have reported the normal CT appearance of feline intrathoracic lymph nodes. The aim of this study was to describe the distribution, number, size and attenuation of presumed normal intrathoracic lymph nodes in cats. Retrospective analysis of the imaging archive in a teaching hospital identified cats that had undergone thoracic CT and were deemed to have no evidence of either intra- or extrathoracic disease that would influence the size of the intrathoracic lymph nodes. Lymph nodes were classified into lymph centres based on anatomical references. Descriptions of the position of each node, number of nodes in each centre, size of each node and attenuation pre- and post-contrast were recorded. Statistical analysis aimed to assess for correlations between these factors and the age, weight and sex of the subjects. Twenty cats were included in the study. One or more lymph nodes were identified in the sternal (n = 19/20), cranial mediastinal (n = 14/20) and tracheobronchial (n = 15/20) centres, while none were identified in other locations. Size varied between lymph centres and within lymph centres where more than one lymph node was identified. Tracheobronchial and sternal nodes were consistent in location, while mediastinal nodes were variable. All nodes were round to ellipsoid in shape and showed moderate enhancement post-contrast. No significant correlations were found with age, weight or sex. This study describes the CT characteristics of presumed normal intrathoracic lymph nodes in cats, and only identified nodes in the sternal, cranial mediastinal and tracheobronchial locations. This study serves as a reference point for CT analysis of feline thoracic lymph nodes.

Incidental fetal imaging with CT: a pictorial essay.

Although CT is not the first choice for abdominal imaging of pregnant patients, it can be indicated for pregnant patients with emergent life-threatening conditions. It is prudent in these cases for the radiologist to be familiar with the normal appearance of the pregnant uterus on CT and to evaluate the female pelvis for potential maternal and fetal abnormalities. We aim to provide examples of the normal CT appearance of the female pelvis related to different gestational ages and to demonstrate variant and abnormal conditions of pregnancy which may be identified by CT.

Pituitary 18F-FDG uptake correlates with serum TSH levels in thyroid cancer patients on 18F-FDG PET/CT.

ObjectiveThe objective of this study was to evaluate the relationship between fluorine-18-fluorodeoxyglucose (18F-FDG) uptake in the pituitary gland and serum thyroid-stimulating hormone (TSH) levels in differentiated thyroid cancer (DTC) patients on 18F-FDG PET/computed tomography (CT).Patients and methodsA total of 215 DTC patients and 215 age-paired and sex-paired healthy screening participants were included. DTC patients were divided into hypothyroid, euthyroid and subclinical hyperthyroid patients according to their serum TSH levels. The relationship between 18F-FDG uptake in the pituitary gland and serum TSH levels was evaluated the in DTC patients, and the pituitary 18F-FDG metabolism was compared in different thyroid status.ResultsThe standardized uptake value of pituitary (SUVp) in all 430 patients was directly correlated with serum TSH levels (r=0.479 and 0.432, all P<0.05). The SUVp in DTC patients was higher than that in 215 healthy participants (z=−10.4, P<0.05). No significant difference of SUVp was observed between euthyroid patients and healthy participants (P=0.145).ConclusionOur study established the positive correlation between pituitary 18F-FDG uptake and serum TSH. TSH values should be measured in patients with incidental pituitary uptake during 18F-FDG PET/CT. L-T4 replacement for DTC patients may well have the same feedback on the thyroid–pituitary axis as the physiologic thyroid status. The diffuse 18F-FDG uptake with normal CT or MRI appearance of the pituitary in patients with DTC indicates physiologic uptake.

Maturation of pelvic ossification centers on computed tomography in normal children.

The pelvis is composed of three paired primary ossification centers: the pubis, the ischium and the ilium. During maturation, multiple secondary ossification centers can be seen in the synchondroses between these bones and in the pelvic apophyses. The fragmented appearance of these centers can be confused with pathology. To examine development of pelvic ossification centers by CT and determine normal appearance throughout childhood. Three pediatric radiologists reviewed 325 pelvic CT scans in children and young adults 5-18years old and graded 6 pelvic ossification centers to evaluate maturational changes in critical structures. Rate and progression of ossification and age at complete fusion vary with gender at the different ossification centers in the growing pelvis. Knowledge of the normal CT appearance of ossification centers throughout childhood is important to differentiate the normal appearance from pathology.

The developing temporal bone: computed tomography measurements and assessment of suture closure from birth to 18 years of age

To describe the normal CT appearance of the developing temporal bone in children from birth to 18years of age. Two hundred and six temporal bone CTs of children from 0.14 to 18.95years were retrospectively selected and reviewed. Temporal bones were measured in a standardized slice orientation using the length of the basal turn of the cochlea, the length and width of the petrous bone, the coronal extent, trailing edge and anterior-posterior dimension of the temporal bone and the angle between petrous bone's length and the midsagittal line in the axial plane showing the basal turn of the cochlea in its greatest extent. Two sutures, two synchondroses and three fissures of the temporal bone were evaluated and graded. Chosen measurements and calculations demonstrate an increase of values from 0 to 18years with the greatest increase occurring during the first 2years of life. The angle between the basal turn of the cochlea and the midsagittal line shows a large variability. Logarithmic trend lines illustrate larger measurements of males as compared to females. The ratio of the basal turn of the cochlea and the length of the petrous bone is about 1:4.1 (f/m) during the first year of life and about 1:6.1 (f)/1:6.8 (m) from 17years onwards. Results of suture closure are described using box-and-whisker plots. The developing temporal bone grows the most during the first 2years of life. Knowledge of changing proportions and suture closure is essential for evaluation of temporal bone CT of children.

Age- and gender-related characteristics of the pubic symphysis and triradiate cartilage in pediatric computed tomography.

There is little information on the pubic symphysis' normal CT appearance in children. We sought to generate age-, gender- and maturity-related symphyseal width appearances in CT scans. Pelvic CT scans performed for any reason during a 6-year period in patients younger than 18years were retrospectively analyzed. The symphysis width was measured in the axial plane and the triradiate cartilage was classified as open or closed. Four hundred twenty-seven CT scans were evaluated and 350 remained for analysis. Age- and gender-related measurements of the symphysis width are illustrated on various centile graphs. When grouping children by age in years 0-6, 7-11, 12-15 and 16-17, mean (standard deviation) symphysis width was 5.4mm (0.9), 5.3mm (1.1), 4.1mm (1.1) and 3.5mm (1.0), respectively, in girls and 5.9mm (1.3), 5.4mm (1.2), 5.2mm (1.1) and 4.0mm (1.0), respectively, in boys. Boys and girls were significantly different in the age groups 12-15years (P<0.001) and 16-17years (P=0.04). In the mature pelvis, the symphyseal gap is significantly (P<0.001) shorter in both genders, and in girls compared to boys (P=0.04). The pubic symphysis width in children differs according to age, gender and maturity. The reference values published herein may help detect symphyseal injury.

Nellix Endovascular Aneurysm Sealing System (EVAS): A New Concept in Endovascular Repair - What the Radiologist Needs to Know

The Nellix endovascular aneurysm sealing system (EVAS), licensed in Europe for treating infrarenal abdominal aortic aneurysms, has distinctive design comprising two balloon-expandable endoframes, each surrounded by a polymer-filled endobag. This review describes the current role of CT in both Nellix follow-up and pre-procedure planning, with reference to the inclusion criteria for Nellix insertion and the deployment technique. Knowledge of the expected evolution of CT features following Nellix insertion is important for recognizing potential complications. Examples of normal post-operative CT appearance, as well as complications seen to date are discussed.

Biphasic 68Ga-PSMA-HBED-CC-PET/CT in patients with recurrent and high-risk prostate carcinoma

Binding of (68)Ga-PSMA-HBED-CC ((68)Ga-PSMA) at prostate cancer (PC) cells increases over time. A biphasic protocol may help separating benign from tumor lesions. The aim of this study was the retrospective evaluation of a diagnostic incremental value of a dual-time point (biphasic) (68)Ga-PSMA-PET/CT in patients with prostate cancer. Retrospective analysis of 35 consecutive patients (49-78 years, median 71) with newly diagnosed PC (12/35) or recurrence of PC (23/35). PET/CT (Gemini TF16, Philips) was acquired 1 h and 3 h p. i. of 140-392 MBq (300 MBq median) (68)Ga-PSMA, followed by a diagnostic contrast CT. PET findings were correlated with histology or unequivocal CT findings. Semiquantitative PET data (SUVmax, SUV mean) were acquired and target-to-background-ratios (T/B-ratio) were calculated for benign and malign lesions for both time points. Size of lymph nodes (LN) on diagnostic CT was recorded. Statistical analysis was performed for assessment of significant changes of semiquantitative PET-parameters over time and for correlation of size and uptake of lymph nodes. One hundred and four lesions were evaluated. Sixty lesions were referenced by histology or unequivocal CT findings, including eight (13.3 %) histopathologically benign lymph nodes, 12 (20 %) histopathologically lymph node metastases, 12 (20 %) primary tumors, three (5 %) local recurrences, and 25 (41.7 %) bone metastases. Forty-four lesions were axillary LN with normal CT-appearance. Benign lesions had significantly lower SUVmax and T/B-ratios compared with malignant findings. Malign lesions showed a significant increase of both parameters over time compared to benign findings. There was no correlation between LN size and SUVmax. The sensitivity, specificity, the positive predictive value and negative predictive value of PET/CT regarding pelvic LN was 94 %, 99 %, 89 %, and 99.5 %, respectively. In contrast to benign tissues, the uptake of proven tumor lesions increases on (68)Ga-PSMA-PET/CT over time. A biphasic PET-study may lead to a better detection of tumor lesions in unequivocal findings.

Normal pediatric postmortem CT appearances.

Postmortem radiology is a rapidly developing specialty that is increasingly used as an adjunct to or substitute for conventional autopsy. The goal is to find patterns of disease and possibly the cause of death. Postmortem CT images bring to light processes of decomposition most radiologists are unfamiliar with. These postmortem changes, such as the formation of gas and edema, should not be mistaken for pathological processes that occur in living persons. In this review we discuss the normal postmortem thoraco-abdominal changes and how these appear on CT images, as well as how to differentiate these findings from those of pathological processes.

Unlocking the jaw: advanced imaging of the temporomandibular joint.

Temporomandibular joint (TMJ) dysfunction is a common condition, affecting up to 28% of the population. The TMJ can be affected by abnormal dynamics of the disk-condyle complex, degenerative arthritis, inflammatory arthritis, and crystal arthropathy. Less commonly, neoplasms and abnormal morphologic features of the condyle are causes of TMJ symptoms. Cross-sectional imaging is frequently used for diagnosis. Knowledge of the normal imaging appearance of the TMJ, its appearance on radiological examination, and interventional techniques are useful for providing a meaningful radiologic contribution. This article will review normal TMJ anatomy; describe the normal ultrasound, CT, and MRI appearances of TMJ; provide imaging examples of abnormal TMJs; and illustrate imaging-guided therapeutic TMJ injection.

Imaging appearance of the lateral rectus-superior rectus band in 100 consecutive patients without strabismus.

The lateral rectus-superior rectus band is an orbital connective tissue structure that has been implicated in a form of strabismus termed sagging eye syndrome. Our purpose was to define the normal MR imaging and CT appearance of this band in patients without strabismus. Orbital MR imaging and CT examinations in 100 consecutive patients without strabismus were evaluated. Readers graded the visibility of the lateral rectus-superior rectus band on coronal T1WI, coronal STIR, and coronal CT images. Readers determined whether the band demonstrated superotemporal bowing or any discontinuities and whether a distinct lateral levator aponeurosis was seen. Reader agreement was assessed by κ coefficients. Association between imaging metrics and patient age/sex was calculated by using the Fisher exact test. The lateral rectus-superior rectus band was visible in 95% of coronal T1WI, 68% of coronal STIR sequences, and 70% of coronal CT scans. Ninety-five percent of these bands were seen as a continuous, arc-like structure extending from the superior rectus/levator palpebrae muscle complex to the lateral rectus muscle; 24% demonstrated superotemporal bowing; and in 82% of orbits, a distinct lateral levator aponeurosis was visible. Increasing patient age was negatively associated with lateral rectus-superior rectus band visibility (P=.03), positively associated with lateral rectus-superior rectus band superotemporal bowing (P=.03), and positively associated with lateral levator aponeurosis visibility (P=.01). The lateral rectus-superior rectus band is visible in most patients without strabismus on coronal T1WI. The age effect with respect to its visibility and superotemporal bowing could represent age-related connective tissue degeneration.

Predicting positive bone marrow biopsies (BMBs) in patients (PTS) with advanced prostate cancer (APC).

180 Background: Advanced prostate cancer (APC) is a molecularly heterogeneous disease, with evidence of clonal evolution that could be responsible for resistance to treatment. About 90% of patients (pts) with APC have bone metastases. The acquisition of a bone marrow biopsies (BMBs) is a safe and feasible technique for obtaining tissue, with a low rate of complications. We hypothesized that pre-biopsy clinical variables may increase the success rate of BMBs in APC. Methods: Standard BMBs of the iliac crest were performed in APC pts between October 2011 and June 2013. All pts signed ethics approved consent. In the control cohort (n=10) BMBs were collected in pts with normal CT and bone scan appearance. Minimum, maximum, and mean Hounsfield Units (HU) of the iliac crest on pre-biopsy CTs were determined. Clinical and laboratory variables were collected from the electronic record system. Biopsies were defined as containing 50 or more or 1 to 50 malignant cells or none (negative). Univariate analysis was performed to determine variables associated with biopsy positivity with 50 or more cells. For variables with p value&lt;0.1, the optimal cut-off point was determined by ROC curve analysis. A multivariate analysis with optimal cut-off points was then performed. Results: A total of 71 BMBs were performed in 57 pts. None of the control biopsies in pts with normal CT and bone scan (10 of 10) contained tumor. A total of 46 of 61 BMBs (75.4%) were positive. 38 of 61 (62.3%) contained 50 or more cells. Prior treatments were docetaxel in 57 (79.2%) and abiraterone in 42 (58%) pts. Bisphosphonates had been used in 21 (28.8%) pts. The significant variables on univariate analysis were ALP more than or equal to 200 IU/L (p=0.059), prostate-specific antigen (PSA) more than or equal to 225 ng/mL (p=0.008), lactate dehydrogenase (LDH) more than or equal to 200 IU/L (p=0.09), mean HU more than or equal to 125 (p=0.000) and maximum HU more than or equal to 550 (p=0.001). These factors were tested in multivariate analysis. Only PSA and mean HU were significant in multivariate analysis. The combined PSA and mean HU score had an ROC AUC of 0.79. Conclusions: A combination of PSA and mean HU on CT could assist physicians in selecting APC patients/ iliac crest site more likely to have a positive BMB. Prospective evaluation is ongoing in a validation set.

Anticlockwise swirl of mesenteric vessels: A normal CT appearance, retrospective analysis of 200 pediatric patients

ObjectiveThe counterclockwise rotation of the SMV on SMA is a normal and non-specific finding, which results in an incomplete swirl formation on CT scans. However, it has a potential to be misinterpreted as ‘midgut volvulus’ resulting in serious clinical implications. The study was done to determine the frequency and degree of counterclockwise rotation of the SMV on SMA on CT in normal otherwise asymptomatic pediatric patients undergoing CT scan. MethodsIn this IRB approved study, we retrospectively analyzed abdominal CT scan examinations of 200 consecutive pediatric patients (age range of 11 days to 18 years), which were performed for different clinical indications over a period of 10 months. They were evaluated for the absence or presence and degree of counterclockwise rotation of the mesenteric vessels. ResultsOf the 200 patients, 128 (64%) patients showed no clockwise or anticlockwise rotation of mesenteric vessels. Counterclockwise rotation of SMV on SMA was seen in 72 (36%) patients. Further, the degree of rotation of vessels was also calculated, based on the criteria proposed by the authors. ConclusionsThe counterclockwise rotation of SMV on SMA gives an appearance of mesenteric whirlpool in otherwise normal mesenteric vessels and can be misinterpreted as midgut volvulus. It is a normal CT appearance and is due to a variation in branching pattern of mesenteric vessels. Awareness of this normal branching pattern of mesenteric vessels is important to avoid an inadvertent laparotomy.

Bacteriology of normal frontal sinuses

PurposeThe aim of this cross-sectional trial was to identify the bacterial flora and to quantify the level of bacterial presence in healthy adult frontal sinus cavities. Materials and methodsNinety five consecutive patients undergoing craniotomy of the anterior cranial fossa were enrolled. All patients were evaluated preoperatively by a sino-nasal questionnaire, nasal endoscopy and CT scan. Exclusion criteria were patients with sinus tumours, presenting a cold in the past 8weeks, having signs or symptoms suggestive of sinus disease, history suggestive of allergic rhinitis and/or asthma, having undergone hospitalization or an outpatient clinic visit within the past 12months, patients with known systemic disease, having previous sinus or nose surgery, history of trauma of the sino-nasal region, or having used systemic antibiotics, steroids, or nasal spray in the past 8weeks. Lavages were obtained from frontal sinuses before craniotomy through trephination of the anterior wall. The sinus was irrigated with sterile saline followed by aspiration. Specimens were inoculated for aerobic and anaerobic organisms. ResultsAfter applying the exclusion criteria, 42 patients (84 sinuses) were finally included in the study. Bacterial organisms were recovered in 12 of 84 (14.28%) sinuses. However, 85.72% of the sinuses were found to be sterile. Bacteria recovered included three different coagulase-negative staphylococci, one Citrobacter diversus and two Micrococcus spp. No anaerobic organism was isolated. ConclusionsThis study demonstrated that the majority of frontal sinuses of asymptomatic adults with normal CT and endoscopic appearance are sterile.

S20 Time-resolved CT pulmonary angiography contrast transit time in patients with pulmonary embolism: a novel functional CT metric of right heart strain?

Introduction and ObjectivesAcute right ventricular (RV) failure is known to cause death in patients with pulmonary embolus due to circulatory collapse. CT pulmonary angiogram (CTPA) is now considered the gold...

Contrast-Enhanced MDCT Characteristics of Parathyroid Adenomas

Minimally invasive directed parathyroidectomy has replaced conventional surgical techniques aimed at exploring all four glands in the bilateral neck. These changes have created the need for better preoperative imaging localization techniques. In this article, we describe the CT imaging characteristics of surgically confirmed adenomas and review anatomy and embryology to aid the radiologist in successfully identifying adenomas using contrast-enhanced CT. Knowledge of normal CT appearance, contrast enhancement, and expected location are critical to correct interpretation of parathyroid adenoma at CT.