Prevalence of Liver Steatosis in Tuberous Sclerosis Complex Patients: A Retrospective Cross-Sectional Study.

Introduction: Tuberous sclerosis complex (TSC) is a genetic disease caused by pathogenetic variants in either the TSC1 or TSC2 genes. Consequently, the mechanistic target of the rapamycin complex 1 (mTORC1) pathway, a regulator of cell growth, metabolism, and survival, becomes inappropriately activated, leading to the development of benign tumors in multiple organs. The role of mTORC1 in lipid metabolism and liver steatosis in TSC patients has not been well-studied, and clinical data on liver involvement in this population are scarce. Methods: We conducted a retrospective, cross-sectional study to compare liver steatosis in TSC patients with age-, sex-, BMI-, and diabetes status-matched controls. Participants with a definite diagnosis of TSC were recruited from the TSC clinic at UZ Brussel. Liver steatosis was quantified using the fat signal fraction from in-phase and out-of-phase MRI, with a threshold of ≥5% defining the presence of steatosis. We also evaluated the prevalence of liver angiomyolipomata in the TSC group and analyzed risk factors for both liver steatosis and angiomyolipomata. Results: The study included 59 TSC patients and 59 matched controls. The mean fat signal fraction was 4.0% in the TSC group and 3.9% in the controls, showing no significant difference (two-tailed Wilcoxon signed ranks test, p = 0.950). Liver steatosis was observed in 15.3% of TSC patients compared to 23.7% of the controls, which was not statistically significant (two-tailed McNemar test, p = 0.267). Liver angiomyolipomata were identified in 13.6% of the TSC cohort. Conclusions: Our study, describing in detail the liver phenotype of TSC patients, did not reveal a significant difference in the prevalence of MRI-assessed liver steatosis in a large cohort of TSC patients compared to a closely matched control group.

Refractory chylothorax after severe vomiting and coughing in a 4-year-old child.

Chylothorax is the accumulation of lymphatic fluid in the pleural space. It is a rare condition with potentially life-threatening disorders. In children, the etiology of chylothorax can be mainly attributed to idiopathic factors, congenital, miscellaneous, trauma and malignancies. Conservative treatments can solve most chylothorax, but refractory chylothorax can be challenging to manage. We herein present the case of a 4-year-old girl with no previous medical history who was admitted to our institution after severe vomiting and right chylothorax. The etiological assessment could not identify specific causes. Initial treatment was conservative but after 14 days, the patient showed no improvement. An exploratory thoracoscopy using indocyanine green showed no active leaks. Pleurodesis was performed and, later on, ligation of the ductus thoracicus. Hereafter, the patient progressed favorably. Even though conservative treatments of chylothorax show a high success rate, the efficacy of additional therapies and the benefits between surgical procedures need further investigation.

Redefining the vascular anatomy of the medial gastrocnemius muscle: A computed tomography angiography study.

BACKGROUND: The medial gastrocnemius (GN) muscle flap is a historical reconstructive option in lower limb reconstruction. The flap is proximally based on the medial sural artery, and it is assumed not possible to harvest a distally based flap because of the absence of other minor pedicles. The aim of this study is to investigate the presence and the anatomy of a distal secondary pedicle given off by the posterior tibial artery (PTA). METHODS: A retrospective CTA study was performed of 120 limbs between April 2018 and June 2020. 3D reconstruction was performed to delineate the anatomy of the distal secondary pedicle, if present. The distance of the pedicle, if found, from the intermalleolar line to the patella was noted. The number of pedicles, if multiple, was documented, as well as branches to the soleus muscle and the skin. RESULTS: A distal pedicle to the gastrocnemius muscle was found in 64% of limbs. The average location from the intermalleolar line is 168 mm. The branching pattern from the PTA showed an isolated vessel going to the distal medial gastrocnemius (32.8%), two branches to the medial gastrocnemius and skin (39.3%), two branches to the medial gastrocnemius and soleus (24.6%), and three branches to the medial gastrocnemius, soleus, and the skin (3.3%). CONCLUSIONS: This study confirms the presence of the secondary axial distal pedicle of the GN muscle. Furthermore, this study confirms that there is a likely association between the distal medial gastrocnemius pedicle and the PTA skin perforators.

The correlation of muscle quantity and quality between all vertebra levels and level L3, measured with CT: An exploratory study.

Introduction: In patients with cancer, low muscle mass has been associated with a higher risk of fatigue, poorer treatment outcomes, and mortality. To determine body composition with computed tomography (CT), measuring the muscle quantity at the level of lumbar 3 (L3) is suggested. However, in patients with cancer, CT imaging of the L3 level is not always available. Thus far, little is known about the extent to which other vertebra levels could be useful for measuring muscle status. In this study, we aimed to assess the correlation of the muscle quantity and quality between any vertebra level and L3 level in patients with various tumor localizations. Methods: Two hundred-twenty Positron Emission Tomography (PET)-CT images of patients with four different tumor localizations were included: 1. head and neck (n = 34), 2. esophagus (n = 45), 3. lung (n = 54), and 4. melanoma (n = 87). From the whole body scan, 24 slices were used, i.e., one for each vertebra level. Two examiners contoured the muscles independently. After contouring, muscle quantity was estimated by calculating skeletal muscle area (SMA) and skeletal muscle index (SMI). Muscle quality was assessed by calculating muscle radiation attenuation (MRA). Pearson correlation coefficient was used to determine whether the other vertebra levels correlate with L3 level. Results: For SMA, strong correlations were found between C1-C3 and L3, and C7-L5 and L3 (r = 0.72-0.95). For SMI, strong correlations were found between the levels C1-C2, C7-T5, T7-L5, and L3 (r = 0.70-0.93), respectively. For MRA, strong correlations were found between T1-L5 and L3 (r = 0.71-0.95). Discussion: For muscle quantity, the correlations between the cervical, thoracic, and lumbar levels are good, except for the cervical levels in patients with esophageal cancer. For muscle quality, the correlations between the other levels and L3 are good, except for the cervical levels in patients with melanoma. If visualization of L3 on the CT scan is absent, the other thoracic and lumbar vertebra levels could serve as a proxy to measure muscle quantity and quality in patients with head and neck, esophageal, lung cancer, and melanoma, whereas the cervical levels may be less reliable as a proxy in some patient groups.

Anatomic study of the profunda artery perforators by multidetector CT scanner and clinical use of the banana-shaped flap design for breast reconstruction.

BACKGROUND: The profunda artery perforator (PAP) flap is a well-known free flap for breast reconstruction. However, a reproducible perforator mapping system has yet to be developed. METHODS: The PAP perforators were localized by CTA using a novel X-Y axis system. Flap dimensions were based on the CTA images and localized PAP-perforators. Perioperative findings and postoperative outcomes were analyzed. RESULTS: A total of 70 lower limbs and 180 PAP perforators were evaluated. An average of 2.78 ± 1.22 and 2.22 ± 0.96 perforators were seen, in the right and left legs, respectively, and were divided in five clusters (PAP1-PAP5) based on their location on the Y-axis. The course of the perforators was noted as well as the average diameter at the origin. The overall average diameter was 1.99 ± 0.86 mm. A banana-shaped PAP-flap was harvested in 10 patients. The mean operative time was 278 min, pedicle length 76 ± 12 mm, and mean flap weight 247 g. No major complications were seen. CONCLUSION: The PAP flap can be mapped by CTA in a reproducible way. The X and Y axes are based on fixed anatomic landmarks and may form the basis for a banana-shaped flap design of the PAP-flap.

The RSNA Pulmonary Embolism CT Dataset.

Supplemental material is available for this article.

Whole-Body MRI for the Detection of Recurrence in Melanoma Patients at High Risk of Relapse.

Introduction: No standard protocol for surveillance for melanoma patients is established. Whole-body magnetic resonance imaging (whole-body MRI) is a safe and sensitive technique that avoids exposure to X-rays and contrast agents. This prospective study explores the use of whole-body MRI for the early detection of recurrences. Material and Methods: Patients with American Joint Committee on Cancer Staging Manual (seventh edition; AJCC-7) stages IIIb/c or -IV melanoma who were disease-free following resection of macrometastases (cohort A), or obtained a durable complete response (CR) or partial response (PR) following systemic therapy (cohort B), were included. All patients underwent whole-body MRI, including T1, Short Tau Inversion Recovery, and diffusion-weighted imaging, every 4 months the first 3 years of follow-up and every 6 months in the following 2 years. A total body skin examination was performed every 6 months. Results: From November 2014 to November 2019, 111 patients were included (four screen failures, cohort A: 68 patients; cohort B: 39 patients). The median follow-up was 32 months. Twenty-six patients were diagnosed with suspected lesions. Of these, 15 patients were diagnosed with a recurrence on MRI. Eleven suspected lesions were considered to be of non-neoplastic origin. In addition, nine patients detected a solitary subcutaneous metastasis during self-examination, and two patients presented in between MRIs with recurrences. The overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were, respectively, 58%, 98%, 58%, 98%, and 98%. Sensitivity and specificity for the detection of distant metastases was respectively 88% and 98%. No patient experienced a clinically meaningful (>grade 1) adverse event. Conclusions: Whole-body MRI for the surveillance of melanoma patients is a safe and sensitive technique sparing patients' cumulative exposure to X-rays and contrast media.

Repeatability and reproducibility of ADC measurements: a prospective multicenter whole-body-MRI study.

OBJECTIVES: Multicenter oncology trials increasingly include MRI examinations with apparent diffusion coefficient (ADC) quantification for lesion characterization and follow-up. However, the repeatability and reproducibility (R&R) limits above which a true change in ADC can be considered relevant are poorly defined. This study assessed these limits in a standardized whole-body (WB)-MRI protocol. METHODS: A prospective, multicenter study was performed at three centers equipped with the same 3.0-T scanners to test a WB-MRI protocol including diffusion-weighted imaging (DWI). Eight healthy volunteers per center were enrolled to undergo test and retest examinations in the same center and a third examination in another center. ADC variability was assessed in multiple organs by two readers using two-way mixed ANOVA, Bland-Altman plots, coefficient of variation (CoV), and the upper limit of the 95% CI on repeatability (RC) and reproducibility (RDC) coefficients. RESULTS: CoV of ADC was not influenced by other factors (center, reader) than the organ. Based on the upper limit of the 95% CI on RC and RDC (from both readers), a change in ADC in an individual patient must be superior to 12% (cerebrum white matter), 16% (paraspinal muscle), 22% (renal cortex), 26% (central and peripheral zones of the prostate), 29% (renal medulla), 35% (liver), 45% (spleen), 50% (posterior iliac crest), 66% (L5 vertebra), 68% (femur), and 94% (acetabulum) to be significant. CONCLUSIONS: This study proposes R&R limits above which ADC changes can be considered as a reliable quantitative endpoint to assess disease or treatment-related changes in the tissue microstructure in the setting of multicenter WB-MRI trials. KEY POINTS: • The present study showed the range of R&R of ADC in WB-MRI that may be achieved in a multicenter framework when a standardized protocol is deployed. • R&R was not influenced by the site of acquisition of DW images. • Clinically significant changes in ADC measured in a multicenter WB-MRI protocol performed with the same type of MRI scanner must be superior to 12% (cerebrum white matter), 16% (paraspinal muscle), 22% (renal cortex), 26% (central zone and peripheral zone of prostate), 29% (renal medulla), 35% (liver), 45% (spleen), 50% (posterior iliac crest), 66% (L5 vertebra), 68% (femur), and 94% (acetabulum) to be detected with a 95% confidence level.

A focused 35-minute whole body MRI screening protocol for patients with von Hippel-Lindau disease.

BACKGROUND: Von Hippel-Lindau (VHL) disease is an autosomal dominantly inherited tumor syndrome. Affected patients develop central nervous system hemangioblastomas and abdominal tumors, among other lesions. Patients undergo an annual clinical screening program including separate magnetic resonance imaging (MRI) of the brain, whole spine and abdomen. Consequently, patients are repeatedly subjected to time-consuming and expensive MRI scans, performed with cumulative Gadolinium injections. We report our experience with a 35-min whole body MRI screening protocol, specifically designed for detection of VHL-associated lesions. METHODS: We designed an MRI protocol dedicated to the typical characteristics of VHL-associated lesions in different imaging sequences, within the time frame of 35 min. Blank imaging of the abdomen is carried out first, followed by abdominal sequences with Gadolinium contrast. Next, the full spine is examined, followed by imaging of the brain. A single dose of contrast used for abdominal imaging is sufficient for further highlighting of spine- and brain lesions, thus limiting the Gadolinium dosage. We used 1.5 Tesla equipment, dealing with fewer artifacts compared to a 3 Tesla system for spine- and abdominal imaging, while preserving acceptable quality for central nervous system images. In addition, imaging on a 1.5 Tesla scanner is slightly faster. RESULTS: From January 2016 to November 2018, we performed 38 whole body screening MRIs in 18 VHL patients; looking for the most common types of VHL lesions in the abdomen, spine, and brain, both for new lesions and follow-up. The one-step approach MRI examinations lead to 6 surgical interventions for clinically significant or symptomatic hemangioblastomas in the brain and spine. One renal cell carcinoma was treated with radiofrequency ablation. In comparison with previous conventional MRI scans of the same patients, all lesions were visible with the focused protocol. CONCLUSIONS: Annual screening in VHL disease can be done in a rapid, safe and sensitive way by using a dedicated whole body MRI protocol; saving MRI examination time and limiting Gadolinium dose.

Deep inferior epigastric artery perforator flap harvest after full abdominoplasty.

Abdominal scars are no longer a contra-indication for abdominal perforator flap harvesting. Few research data exists about the regeneration potential of the abdominal wall's perforator system. Therefore, previous abdominoplasty with umbilical transposition is an absolute contra-indication for a DIEaP-flap (deep inferior epigastric artery perforator flap). A 50-year-old patient required a breast reconstruction of the right breast, 10 years after an abdominoplasty with undermining of the superior abdomen and umbilical transposition. The patient was scheduled for a free lumbar artery perforator (LaP) flap. The preoperative computed tomography-angiography mapping showed nice lumbar perforators and to our surprise a good-sized DIEa perforator in the peri-umbilical region. The DIEa perforator on the right hemi-abdomen, consisting of two veins and one artery, was pulsatile and found suitable in size. A classical flap harvest and transfer was further performed. This case report is the first in which a dominant perforator is found in the area of undermining after a full abdominoplasty with umbilical repositioning. Further investigations regarding the nature and timing of re-permeation or regeneration of perforators after abdominoplasty are to be done. Nevertheless, we are convinced that with appropriate perforator mapping and a suitable plan B, previous abdominoplasty is no longer an absolute but a relative contra-indication for performing DIEaP-flap.

MR lymphography in patients with upper limb lymphedema: The GPS for feasibility and surgical planning for lympho-venous bypass.

BACKGROUND AND OBJECTIVES: Lymphedema is caused by insufficient lymphatic drainage leading to abnormal accumulation of interstitial fluid within soft tissues. Lympho-venous anastomosis (LVA), as a surgical option for selected patients, is widely applied. Through preoperative localization of functional lymphatics with indocyanine green, real time visualization of functioning lymphatic vessels is possible. This examination is time consuming and operator dependant and is not suitable to differentiate the ratio of fat hypertrophy to liquid edema. We investigated whether MR lymphangiography is accurate for imaging functional lymphatics and adjacent veins in arms. Furthermore, we investigated the accuracy and predictability of preoperative mapping for the feasibility of performing LVA and the preoperative decision making in lymphedema surgery. METHODS: A prospective study was performed in which 25 patients suffering from lymphedema of the upper extremity were examined. MR lymphography with contrast agent injection in a deep dermal plane was performed. RESULTS: Precise localization of lymphatic vessels crossing a vein was achieved in 18 of 25 arms. In 16 of the 18 patients in whom functional lymphatics were localized with an adjacent vein on MRI an LVA was performed successfully. CONCLUSIONS: MR lymphangiography is an accurate and reproducible method for imaging and mapping of lymphatic channels in the lymphedemateous limb.

Central nervous system gadolinium accumulation in patients undergoing periodical contrast MRI screening for hereditary tumor syndromes.

BACKGROUND: Patients with hereditary tumor syndromes undergo periodical magnetic resonance imaging (MRI) screening with Gadolinium contrast. Gadolinium accumulation has recently been described in the central nervous system after repeated administrations. The prevalence and rate of accumulation in different subgroups of patients are unknown. Neither are the mechanism nor clinical impact. This may cause uncertainty about the screening. To explore the prevalence and rate of Gadolinium accumulation in different subgroups, we retrospectively analyzed MRIs of patients with von Hippel-Lindau disease (VHL) and Tuberous Sclerosis Complex (TSC). METHODS: We determined the prevalence and rate of accumulation in the dentate nucleus and globus pallidus on unenhanced T1-weighted MRI from VHL and TSC patients. We compared the signal intensities of these regions to the signal intensity of the pons. We evaluated the impact of number of MRIs, kidney function and liver function on Gadolinium accumulation. RESULTS: Twenty eight VHL patients and 24 TSC patients were included. The prevalence of accumulation in the dentate nucleus and globus pallidus increased linearly according to number of Gadolinium enhanced MRIs and was higher in the VHL group (100%). A significant linear correlation between number of MRIs and increased signal intensity was observed in the VHL group. CONCLUSIONS: Gadolinium accumulation occurs in almost all patients undergoing contrast MRI screening after >5 MRIs. We advocate a screening protocol for patients with hereditary tumor syndromes that minimizes the Gadolinium dose. This can be accomplished by using a single administration to simultaneously screen for brain, spine and/or abdominal lesions, using an MRI protocol focused on either VHL- or TSC-specific lesions. Higher prevalence and rate of accumulation in VHL patients may be explained by the typical vascular leakage accompanying central nervous system hemangioblastomas.

Lumbar Artery Perforator Flap: An Anatomical Study Using Multidetector Computed Tomographic Scan and Surgical Pearls for Breast Reconstruction.

BACKGROUND: Breast reconstruction with the lumbar artery perforator flap is indicated in patients with unfavorable abdominal donor site. In addition to their clinical experience with lumbar artery perforator free flap breast reconstruction, the authors present an anatomical study of the origin and course of the perforators. METHODS: Images of multidetector computerized tomography scans were used to visualize the location of the dominant lumbar artery perforator in 20 patients. The medical files of the authors' patients who underwent lumbar artery perforator flap breast reconstruction were also analyzed. RESULTS: Multidetector computed tomographic imaging in 20 female patients with a mean age of 47 years revealed an equal number of dominant perforators (10 left and 10 right); 60 percent were third lumbar artery perforators, 30 percent were fourth, and the remaining were second. The dominant perforators were mainly located 42.6 mm from the y axis at their origin at the transverse process, and 69.5 mm when emerging in the subcutaneous tissue. Six patients had nine successful lumbar artery perforator flaps for breast reconstruction. Average operative time was 270 minutes. Due to shortness of pedicle and mismatching between diameter of lumbar artery and internal mammary artery, vascular bypass (harvested from the deep inferior epigastric vessels) was required in 50 percent of the cases. The major complication at the donor site was seroma (80 percent). CONCLUSIONS: The lumbar artery perforator has a constant anatomical location. The free lumbar artery perforator flap provides an ample amount of tissue for breast reconstruction; however, its major disadvantages are the small artery diameter, shortness of the pedicle, and high seroma rate at the donor site. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

[A patient with high creatinine levels but no renal failure: reversed autodialysis in a patient with a ruptured bladder]. / Een patiënt met hoog creatinine maar zonder nierfalen: omgekeerde auto-dialyse bij een patiënt met een blaasruptuur.

BACKGROUND: In case of a ruptured bladder with urine leakage into the peritoneal cavity 'reversed autodialysis' can occur, in which urea and creatinine diffuse back into the bloodstream via the peritoneum. This causes clinical signs of pseudorenal failure, with raised concentrations of creatinine and urea. The urea/creatinine ratio does not change. CASE DESCRIPTION: A 34-year-old female patient experienced increasing abdominal pain 3 days after laparoscopic myomectomy. Acute renal failure was suspected because of increased serum concentrations of creatinine and urea, but no cause could be found. There was a build-up of fluid in the abdominal cavity, which proved to be urine originating from an iatrogenic rupture of the bladder. Serum levels normalised following repair of the rupture. CONCLUSION: If serum creatinine levels rise rapidly following abdominal surgery or blunt abdominal trauma the bladder should be examined for possible perforation, particularly if the abdominal dimension increases. A ruptured bladder leading to pseudorenal failure is an indication for rapid surgical intervention.

Comparative Interpretation of CT and Standard Radiography of the Pleura.

Many diseases affect the pleural space in both adults and children, including common diseases such as pneumonia, cancer and heart failure. Pleural effusion is the most common manifestation of pleural disease, and it is often a secondary effect of another disease process. Imaging plays a crucial role in the management of pleural disease. Chest radiography often remains the first examination in the assessment of these patients. Depending on the clinical context, the optimal imaging technique for further evaluation might be computed tomography (CT), ultrasound (US), or magnetic resonance (MR).