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Biomedical subjects

Peter R Mueller

Publications and source records attributed to Peter R Mueller.

At least 73 records · Page 4Linked to original sources
PubMed2002

Using multidetector CT for preoperative vascular evaluation of liver neoplasms: technique and results.

OBJECTIVE: The purpose of our study was to evaluate the performance of CT angiography using multidetector CT (MDCT) for preoperative vascular evaluation in candidates who were scheduled for liver neoplasm resection. SUBJECTS AND METHODS: Forty-two consecutive subjects with malignant liver tumors scheduled for resection were studied with multiphase MDCT. The first 22 subjects underwent both multiphase MDCT angiography and catheter angiography before surgery. The subsequent 20 subjects underwent only preoperative CT angiography. Postprocessing was performed, and the images were analyzed for the depiction of arterial, portal vein, and hepatic vein anatomy and for the identification of important vascular variants. The postprocessing findings were compared and correlated with the findings from catheter angiography (22/42) or intraoperative sonography (42/42) and surgery (42/42). RESULTS: Arterial anomalies were detected on the images of 17 of 42 patients, including a replaced right hepatic artery in five, replaced left hepatic artery in six, accessory right and left hepatic arteries in two, common trunk for the celiac and superior mesenteric arteries in one, and early bifurcation of the celiac artery in one. In 22 patients in whom catheter angiography confirmation was available, the number of arteries and almost all the significant anomalies were correctly identified on CT angiography (accuracy, 97%; sensitivity, 94%; specificity, 100%). In the subset of 20 patients who underwent MDCT angiography without catheter angiography confirmation, all clinically relevant information was provided by CT angiography. The portal and hepatic vein anatomy and the relationships of the liver tumors to the neighboring venous structures were shown on CT. CONCLUSION: Multidetector CT provides valuable preoperative information about hepatic vascular architecture and can be used as a noninvasive alternative to catheter angiography before oncologic liver surgery.

Adult↗
PubMed2002

Percutaneous nonvascular splenic intervention: a 10-year review.

OBJECTIVE: We performed a retrospective review of our experiences with percutaneous splenic interventions to evaluate the safety and usefulness of these procedures. We examined both the success rate and the complication rate. MATERIALS AND METHODS: We used our electronic database to perform a retrospective analysis of patients treated from January 1990 to December 2000. Thirty-nine imaging-guided percutaneous splenic procedures were performed in 38 patients: 27 men and 11 women who ranged in age from 17 to 83 years (mean age, 56.5 years). For 28 procedures, sonographic guidance was used, and for 11, CT guidance was used. Procedures performed included splenic biopsy (n = 24), fluid aspiration (n = 8), and fluid drainage (n = 7). RESULTS: Splenic biopsy was successful in 91% of the procedures; fluid aspiration, in 100%; and fluid drainage, in 86%. The overall complication rate was 10.3%, with three patients requiring emergency splenectomy as a result of massive bleeding after the procedure. Two of these patients had previously unrecognized vascular tumors, and one had concomitant refractory thrombocytopenia. CONCLUSION: This study suggests that splenic biopsy can be performed safely and is of considerable value in diagnosis. Our findings also show that percutaneous catheter drainage of splenic abscesses is successful and that splenectomy should be reserved for failed percutaneous drainage. The complications that occur after procedures on vascular tumors emphasize the importance of requiring normal coagulation parameters before the procedure because the vascular nature of the lesion may be difficult to recognize on imaging before the procedure.

Adolescent↗
PubMedDate not supplied

The difficult biopsy: let's make it easier.

Image-guided percutaneous biopsies of abdominal and pelvic organs are an integral part of the daily practice of many radiologists. Fortunately, most image-guided percutaneous biopsies are straightforward. At times, however, image-guided percutaneous biopsies can be technically challenging due to various factors, including proximity of surrounding vessels or organs, "moving targets" due to respiratory motion, or difficulties in detecting lesions with certain imaging modalities. The purpose of this manuscript is to discuss techniques that can be utilized to increase the successful biopsy of "difficult" lesions. Choices of imaging modality for guiding needle placement will be discussed, as will the use of alternative access routes such as transgluteal, transvaginal, and other transorgan approaches. Factors to improve the accessibility of lesions, including patient positioning and the timing of contrast injections that improve lesion detection, will be discussed.

Biopsy↗
PubMedDate not supplied

State of the art in adrenal imaging.

The purposes of this article were to outline the current state of adrenal imaging, to highlight new developments, and to review the current radiologic advances that provide improved functional and structural information about adrenal disorders.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

"Hot" spots in hybrid positron emission tomography/computed tomography scanning of the abdomen: protocols, indications, interpretation, responsibilities, and reimbursements.

Although introduction of hybrid positron emission tomography/computed tomography (PET/CT) scanners represents an important development in field of radiology, the alliance of functional imaging with structural imaging has raised many controversial issues. The present review describes some of the important issues in hybrid PET/CT such as specific indications, protocols that deliver diagnostic quality CT scans while ensuring radiation dose associated with hybrid PET/CT examination are minimized, and the feasibility, desirability, and timing of oral and intravenous contrast administration. The issues of clinical indications for hybrid PET/CT versus PET alone will be discussed as well as the role of the CT component (ie, for diagnosis or transmission source alone) are discussed. The logistics of hybrid PET/CT scan interpretation, including the roles of radiologists and nuclear medicine physicians, will be discussed. This review describes the pertinent medical literature and discusses our experience with suitable examples.

Abdomen↗
PubMedDate not supplied

Right-sided colonic diverticulitis: CT findings.

Right-sided colonic diverticulitis is an uncommon but clinically significant condition as it closely mimics other common acute right-sided abdominal conditions like acute appendicitis and cholecystitis. CT can provide a rapid and accurate diagnosis of this condition and thereby prevent unnecessary laparotomy and surgical procedures since it is essentially a benign self-limiting condition requiring medical treatment. It is the aim of this pictorial essay to describe the CT findings and increase awareness among radiologists of this condition.

Acute Disease↗
PubMedDate not supplied

Rare benign and malignant appendiceal lesions: spectrum of computed tomography findings with pathologic correlation.

Although acute appendicitis is the most common disease of the appendix, the appendix can be involved by a wide range of diseases. Diseases other than acute appendicitis may produce signs and symptoms indistinguishable from those of acute appendicitis. Computed tomography (CT) can provide important information for diagnosis and evaluation of appendiceal diseases. The various CT and histologic features of appendiceal benign and neoplastic diseases are discussed, illustrated, and correlated in this article. Radiologists need to understand the full spectrum of appendiceal abnormalities, their underlying pathologic changes, and associated CT imaging findings.

Adult↗
PubMedDate not supplied

Multidetector-row computed tomography angiography for planning intra-arterial chemotherapy pump placement in patients with colorectal metastases to the liver.

PURPOSE: The purpose of this study was to evaluate the use of multidetector computed tomography (MDCT) in the preoperative arterial evaluation of patients scheduled to undergo intra-arterial chemotherapy pump placement. METHODS: Computed tomography scans of 30 patients with hepatic malignancies who were imaged with multiphase MDCT angiography for intra-arterial chemotherapy pump placement were retrospectively analyzed. Dual-phase helical CT was performed, and the arterial phase images were processed to depict the arterial anatomy and to identify pertinent anomalies. All findings were compared and correlated with surgical findings or catheter angiography if surgery was contraindicated. RESULTS: Arterial anomalies identified on CT angiography in 20 of 30 patients included a replaced right hepatic artery (RHA; n = 6) or left hepatic artery (LHA; n = 8), a replaced common hepatic artery (n = 1), an accessory RHA (n = 2) or LHA (n = 6), a replaced gastroduodenal artery (GDA; n = 2), an extrahepatic connection between the accessory RHA and the replaced RHA (n = 1), and a common origin composed of the GDA and RHA and LHA (n = 2). There were no additional arteries or anomalies identified by catheter angiography, when available, or during surgery. Only 1 variant, an accessory hepatic artery, was not located during surgery. In 2 patients, the surgical team decided that pump placement was not feasible because of overly complex anatomy as determined by CT angiography. Computed tomography angiography showed an overall sensitivity of 100% and specificity of 97%. CONCLUSIONS: Multidetector computed tomography angiography is accurate for the preoperative evaluation of normal and aberrant hepatic vasculature in patients under consideration for intra-arterial chemotherapy pump placement. Axial images alone permit recognition of vascular anomalies, including complex anatomy. Nevertheless, 3-dimensional rendering is useful to evaluate complex vascular anatomy and does not require catheter angiographic confirmation. In addition to aiding in selecting patients ideal for pump placement, MDCT permits noninvasive planning of their surgical approach.

Aged↗
PubMedDate not supplied

Characterization of small liver lesions: Added role of MR after MDCT.

OBJECTIVE: The purpose of this study is to evaluate the added role of magnetic resonance imaging (MR) in characterizing subcentimeter focal liver lesion(s) detected on multidetector row helical computed tomography (MDCT). MATERIALS AND METHODS: A retrospective analysis was performed in 59 noncirrhotic patients with focal subcentimeter liver lesion(s) detected on a 4- or 16-slice MDCT. All patients had a gadolinium enhanced liver MR on 1.5-T systems within 6 weeks after MDCT. Imaging diagnosis was graded on an ordinal scale of 0-5 (0, normal; 1, definitely benign; and 5, definitely malignant). The final diagnosis was established either by histopathology or follow-up imaging for a period of at least 6 months. Receiver operating characteristic analysis was performed to compare the performances of MDCT and MR in characterization of subcentimeter liver lesions. RESULTS: A total of 178 lesions were detected on MDCT in 59 patients. Of these lesions, 129 (72.5%) lesions were benign and the remaining 49 were malignant. The sensitivity, specificity, positive predictive value, and negative predictive value in differentiation of benign from malignant lesions on MDCT were 81.2%, 77.3%, 60.5%, 90.6 % and on MR were 83.3%, 97.5%, 92.1%, and 94.4 %, respectively. Comparative receiver operating characteristic analysis showed an area under curve for MDCT = 0.76 and MR = 0.95 (P < 0.001). CONCLUSIONS: Liver MR has significantly higher accuracy for characterization of subcentimeter focal liver lesions discovered on MDCT.

Adult↗
PubMedDate not supplied

Sonohysterographic findings of endometrial and subendometrial conditions.

Sonohysterography has become the standard test in the evaluation of dysfunctional uterine and postmenopausal bleeding because it allows reliable differentiation between focal and diffuse endometrial and subendometrial lesions, with the most common being polyps and submucosal fibroids. An endometrial polyp usually appears as a well-defined, homogeneous, polypoid lesion that is isoechoic to the endometrium with preservation of the endometrial-myometrial interface. Atypical polyps have cystic components, multiplicity, a broad base, and hypoechogenicity or heterogeneity. Submucosal fibroids are usually broad-based, hypoechoic, well-defined, solid masses with shadowing and an overlying layer of echogenic endometrium that distorts the endometrial-myometrial interface. Atypical fibroids are pedunculated or have a multilobulated surface. The major advantage of sonohysterography is that it can accurately depict the percentage of the fibroid that projects into the endometrial cavity. Endometrial hyperplasia usually appears as diffuse thickening of the echogenic endometrial stripe without focal abnormality, but occasionally focal hyperplasia can be seen. Endometrial cancer is typically a diffuse process, but early cases can appear as a polypoid mass. Adhesions usually appear as mobile, thin, echogenic bands that bridge a normally distensible endometrial cavity, but occasionally thick, broad-based bands or complete obliteration of the endometrial cavity is seen. Although endometrial lesions have characteristic features, a wide range of appearances is possible, with significant overlap between entities. Radiologists should be familiar with the broad spectrum of findings that may be seen at sonohysterography in both benign and malignant processes to raise the appropriate level of concern and to direct the clinician toward the appropriate means of diagnostic biopsy or surgery.

Algorithms↗
PubMedDate not supplied

Algorithmic approach to CT diagnosis of the abnormal bowel wall.

Computed tomography demonstrates intestinal wall abnormalities that can be analyzed by categorizing attenuation changes in the intestinal wall and transposing morphologic characteristics learned from barium studies. These attenuation patterns include white, gray, water halo sign, fat halo sign, and black. The white pattern represents avid contrast material enhancement that uniformly affects most of the thickened bowel wall. If the bowel wall is enhanced to a degree equal to or greater than that of venous opacification in the same scan, it should be classified in the white attenuation pattern. Common diagnoses with this pattern include idiopathic inflammatory bowel diseases and vascular disorders. The gray pattern is defined as a thickened bowel wall with limited enhancement whose homogeneous attenuation is comparable with that of enhanced muscle. This pattern is used to differentiate between benign and malignant disease, but it is the least specific of the patterns and should be combined with morphologic observations. The water halo sign indicates stratification within a thickened bowel wall that consists of either two or three continuous, symmetrically thickened layers. Common diagnoses with this sign include idiopathic inflammatory bowel diseases, vascular disorders, infectious diseases, and radiation damage. The fat halo sign refers to a three-layered target sign of thickened bowel in which the middle or "submucosal" layer has a fatty attenuation. Common diagnoses with this sign include Crohn disease in the small intestine and idiopathic inflammatory bowel diseases in the colon. Black attenuation is the equivalent of pneumatosis, and this pattern is commonly seen in ischemia, infection, and trauma.

Algorithms↗
PubMedDate not supplied

CT-guided transgluteal drainage of deep pelvic abscesses: indications, technique, procedure-related complications, and clinical outcome.

Deep pelvic abscesses may present a unique challenge for percutaneous drainage because of numerous overlying structures, which preclude safe percutaneous access. These structures include the pelvic bones, intestine, bladder, iliac vessels, and gynecologic organs. Use of the transgluteal approach to drain these abscesses can circumvent these obstacles and provide a useful surgical alternative or a temporizing measure. The transgluteal approach requires a thorough understanding of the anatomy of the sciatic foramen region and associated anatomic structures. The ideal approach for transgluteal access is to insert the catheter as close to the sacrum as possible, at the level of the sacrospinous ligament. Transgluteal drainage can be performed with the tandem-trocar technique or the Seldinger technique. Modifications of the procedure are needle aspiration not followed by catheter placement, use of the angled gantry technique, bilateral transgluteal drainage, combined anterior and posterior drainage, and drainage of necrotic pelvic masses. The transgluteal approach is a useful option in pediatric patients. Daily catheter care is essential for successful percutaneous catheter therapy. Although pain has been cited as a common complication of the technique, this complication can be minimized with judicious use of analgesia and a meticulous technique. Other complications are hemorrhage and catheter malposition.

Abdominal Abscess↗
PubMedDate not supplied

Urine leaks and urinomas: diagnosis and imaging-guided intervention.

Urine leaks from the kidney, ureter, bladder, and urethra most commonly result from trauma. Urinomas may be occult initially and may lead to complications such as abscess formation and electrolyte imbalances if not promptly diagnosed and appropriately managed. Radiologists play a key role in diagnosing urine leaks and determining their cause and extent. Contrast material-enhanced computed tomography (CT) with delayed imaging, CT cystography, and retrograde urethrography are the diagnostic imaging studies of choice. Studies such as intravenous pyelography, antegrade and retrograde pyelography, renal scintigraphy, and imaging-guided needle aspiration may play complementary diagnostic roles. In some instances, the role of the radiologist ends with the diagnosis of urine leaks, after which patients are treated conservatively or perhaps surgically. Uncomplicated renal urine leaks, extraperitoneal urinary bladder rupture, and type 1 urethral injuries are generally managed conservatively. Urine leaks that require more extensive, imaging-guided treatment can usually be managed safely and effectively with a combination of percutaneous urinoma drainage catheters, percutaneous nephrostomy catheters, ureteral stents, and bladder drainage. In the appropriate setting, use of these management options may reduce urinoma-related complications and limit or totally eliminate the need for urologic surgery.

Adolescent↗
PubMedDate not supplied

Importance and effects of altered workplace ergonomics in modern radiology suites.

The transition from a film-based to a filmless soft-copy picture archiving and communication system (PACS)-based environment has resulted in improved work flow as well as increased productivity, diagnostic accuracy, and job satisfaction. Adapting to this filmless environment in an efficient manner requires seamless integration of various components such as PACS workstations, the Internet and hospital intranet, speech recognition software, paperless electronic hospital medical records, e-mail, office software, and telecommunications. However, the importance of optimizing workplace ergonomics has received little attention. Factors such as the position of the work chair, workstation table, keyboard, mouse, and monitors, along with monitor refresh rates and ambient room lighting, have become secondary considerations. Paying close attention to the basics of workplace ergonomics can go a long way in increasing productivity and reducing fatigue, thus allowing full realization of the potential benefits of a PACS. Optimization of workplace ergonomics should be considered in the basic design of any modern radiology suite.

Asthenopia↗