Torsion of the Gallbladder Diagnosed by Magnetic Resonance Cholangiopancreatography

Torsion of the gallbladder is a rare entity that is difficult to diagnose preoperatively, the principal differential diagnosis being cholecystitis. The condition occurs most often in the elderly. Although its etiology is unknown, the presence of a redundant mesentery is a prerequisite for torsion. Computed tomography, ultrasound, and magnetic resonance cholangiopancreatography can provide important diagnostic clues. Torsion of the gallbladder occurs when it twists axially, with subsequent occlusion of bile or blood flow. Therefore, prompt surgical treatment is necessary in order to prevent necrosis and perforation. In the present study, we report a case of torsion of the gallbladder diagnosed by magnetic resonance cholangiopancreatography. This condition was successfully treated by laparoscopic cholecystectomy.     

Catastrophic Polyethylene Failure Diagnosed With Magnetic Resonance Imaging in a Painful Total Knee Arthroplasty

Determining the etiology of a painful knee after arthroplasty can be extremely challenging. Traditionally, orthopedists relied mainly on physical examination, laboratory results, serial radiographs, and 3-phase bone or indium-labeled white blood cell scans; however, recent advances in magnetic resonance imaging (MRI) software have given orthopedists another powerful tool in their diagnostic armamentarium. We provide the MRI software modification technique for metallic artifact reduction as well as present a novel case in which MRI was used to diagnose catastrophic polyethylene postfailure in a posterior cruciate ligament substituting knee. Although the role for MRI in the postarthroplasty knee has yet to be clearly defined, its utility in working up a painful arthroplasty when history, physical examination, and other diagnostic utilities fail to provide answers is clearly demonstrated in this case.     

Duodenal Pancreatic Heterotopy Diagnosed by Magnetic Resonance Cholangiopancreatography: Report of a Case

We describe herein the case of a heterotopic pancreas that caused stenosis in the second portion of the duodenum. A 46-year-old man presented with upper abdominal pain and a 12-month history of intermittent vomiting. There was no history of melena, hematochezia, hematemesis, clay-colored stools, jaundice, or hepatitis and he did not describe any food dyscrasias, although fatty foods and alcohol seemed to make the symptoms worse. No specific medication or change in position relieved the pain. An initial diagnosis of chronic pancreatitis with multiple pseudocysts was made on the basis of elevated serum amylase and lipase levels, and abdominal ultrasonography and computed tomography (CT) findings. Medical treatment with octreotide was given for 8 weeks, but without any marked effect. Double-contrast barium examination and esophagogastroduodenoscopy were not diagnostic. Magnetic resonance (MR) cholangiopancreatography revealed findings indicative of cystic dystrophy of a heterotopic pancreas (CDHP), and an endoscopy supported this diagnosis. A pancreatoduodenectomy was performed and pathological examination confirmed a diagnosis of CDHP. In our opinion, MR cholangiopancreatography is the diagnostic tool of choice when CDHP is suspected. Received: August 21, 2000 / Accepted: March 6, 2001     

腰椎间盘突出症根性征的影像学表现分析

目的:探讨使用MRM诊断腰椎间盘突出症神经根性受压症状体征的价值及技术方法.方法:选择根性征阳性及阴性共2组腰椎间盘突出症患者,进行常规CT或MRI及MRM扫描,资料进行分析.结果:神经根受压症状体征对MRM图像上神经根鞘袖内脑脊液截断征象有显著影响(P<0.01),对硬膜囊有无压迹无显著影响(P>0.05),对神经根鞘袖走行正常与改变无显著影响(P>0.05),MRM图像上神经根鞘袖受压、不受压患者MRI显示椎间盘突出大小无显著差异(P>0.05).结论:MRM较MRI或CT能更真实的反映腰椎间盘突出症患者神经根受压状态,与临床症状体征较一致,是CT或MRI的重要补充.     

Predicting Consistency of Meningioma by Magnetic Resonance Imaging

Objective Meningioma consistency is important because it affects the difficulty of surgery. To predict preoperative consistency, several methods have been proposed; however, they lack objectivity and reproducibility. We propose a new method for prediction based on tumor to cerebellar peduncle T2-weighted imaging intensity (TCTI) ratios.Design The magnetic resonance (MR) images of 20 consecutive patients were evaluated preoperatively. An intraoperative consistency scale was applied to these lesions prospectively by the operating surgeon based on Cavitron Ultrasonic Surgical Aspirator (Valleylab, Boulder, Colorado, United States) intensity. Tumors were classified as A, very soft; B, soft/intermediate; or C, fibrous. Using T2-weighted MR sequence, the TCTI ratio was calculated. Tumor consistency grades and TCTI ratios were then correlated.Results Of the 20 tumors evaluated prospectively, 7 were classified as very soft, 9 as soft/intermediate, and 4 as fibrous. TCTI ratios for fibrous tumors were all ≤ 1; very soft tumors were ≥ 1.8, except for one outlier of 1.66; and soft/intermediate tumors were > 1 to < 1.8.Conclusion We propose a method using quantifiable region-of-interest TCTIs as a uniform and reproducible way to predict tumor consistency. The intraoperative consistency was graded in an objective and clinically significant way and could lead to more efficient tumor resection.     

Quantitative Magnetic Resonance Imaging of Human Brain Development: Ages 4-18

Brain magnetic resonance images (MRI) of 104 healthy childrenand adolescents, aged 4–18, showed significant effectsof age and gender on brain morphometry. Males had larger cerebral(9%) and cerebellar (8%) volumes (P < 0.0001 and P = 0.008.respectively), which remained significant even after correctionfor height and weight After adjusting for cerebral size, theputamen and globus pallidus remained larger in males, whilerelative caudate size was larger in females. Neither cerebralnor cerebellar volume changed significantly across this agerange. Lateral ventricular volume increased significantly inmales (trend for females), with males showing an increase inslope after age 11. In males only, caudate and putamen decreasedwith age (P = 0.007 and 0.05, respectively). The left lateralventricles and putamen were significantly greater than the rightP = 0.01 and 0.0001, respectively). In contrast, the cerebralhemispheres and caudate showed a highly consistent right greater-than-leftasymmetry (P < 0.0001 for both). All volumes demonstrateda high degree of variability. These findings highlight gender-specificmaturational changes of the developing brain and the need forlarge gender-matched samples in pediatric neuropsychiatric studies.     

Further Imaging for Suspected Isolated Greater Trochanteric Fractures: Multiplanar Reformation Computed Tomography or Magnetic Resonance Imaging

BackgroundMost isolated greater trochanter (IGT) fractures are treated conservatively. However, some require surgical fixation although indications for surgery have not yet been established. Many surgeons perform surgical fixation when the intertrochanteric extension crosses the midline on magnetic resonance (MR) images. Nevertheless, for mechanical strength, cortical bone integrity is more important than that of intramedullary cancellous trabeculae. We retrospectively evaluated the clinical usefulness of multiplanar reformation computed tomography (MPR CT) in determining treatment strategies for IGT fractures.MethodsWe evaluated 99 cases of suspected IGT fractures between October 2004 and December 2019. They were 66 women and 33 men with a mean age of 77 years. The mean follow-up period was 34 months. Most patients were evaluated with plain radiographs, followed by additional imaging study via MPR CT in 65 cases, magnetic resonance imaging (MRI) in 5 cases, and both in 17 cases. Typically, fractures were fixed surgically when a cortical breakage was detected in the intertrochanteric area on MPR CT, while fractures without evidence of cortical breakage on MPR CT were treated conservatively.ResultsIn 13 out of 82 cases evaluated by MPR CT, incomplete cortical breakage in the intertrochanteric area was detected, of which 10 were treated surgically. The remaining 3 cases were treated conservatively due to patient’s refusal, poor medical condition, and failure to detect breakage. Of 69 cases without cortical breakage, 61 cases were successfully treated conservatively. Among the 17 cases evaluated by both MPR CT and MRI, cortical breakage was detected in 3, of which the intertrochanteric extension crossed the midline on the MR image only in 1 case. Of the remaining 14 cases without breakage, the intertrochanteric extension crossed the midline in 5. Among these 5 cases, 3 were treated conservatively.ConclusionsThe results suggest that MPR CT is a useful imaging modality for further evaluation of IGT fractures. It was especially valuable in evaluating cortical bone integrity, which may be more critical for fracture stability.     

Study of the Sniffing Position by Magnetic Resonance Imaging

Background: The "sniffing position" is widely considered essential to the performance of orotracheal intubation and has become the cornerstone of training in anesthesiology. However, the anatomic superiority of this patient head position has not been established.

Methods: Eight healthy young adult volunteers underwent magnetic resonance imaging scanning in three anatomic positions: head in neutral position, in simple extension, and in the "sniffing position" (neck flexed and head extended by means of a pillow). The following measurements were made on each scan: (1) the axis of the mouth (MA); (2) the pharyngeal axis (PA); (3) the laryngeal axis (LA); and (4) the line of vision. The various angles between these axes were defined: [alpha] angle between the MA and PA, [beta] angle between PA and LA, and [delta] angle between line of vision and LA.

Results: Both simple extension and sniffing positions significantly improved (P < 0.05) the [delta] angle associated with best laryngoscopic view. Our results show that the [beta] value increases significantly (P < 0.05) when the head position is shifted from the neutral position ([beta] = 7 +/- 6[degrees]) to the sniffing position ([beta] = 13 +/- 6[degrees]), and the [alpha] value slightly (but significantly) decreases (from 87 +/- 10[degrees] to 63 +/- 11[degrees];P < 0.05). Anatomic alignment of the LA, PA, and MA axes is impossible to achieve in any of the three positions tested. There were no significant differences between angles observed in simple extension and sniffing positions.