Zeev V. Maizlin

Can CT Replace MRI in Preoperative Assessment of the Circumferential Resection Margin in Rectal Cancer

The surgical circumferential resection margin in total mesorectal excision surgery is defined by the relationship of the tumor to the mesorectal fascia. Patients with anticipated tumor invasion of the mesorectal fascia receive neoadjuvant therapy to downstage/downsize the tumor and to obtain tumor-free resection margins. Tumor relationship to the mesorectal fascia is accurately determined by MRI. Compared with MRI, multidetector-row computed tomography is more widely available, faster, less costly, and provides the ability to simultaneously assess the liver, peritoneum, and retroperitoneum for metastases. PURPOSE: The objective of this study was to compare the accuracy of multidetector-row CT with conventional MRI in diagnosis of rectal cancer invasion of the mesorectal fascial envelope. MATERIALS AND METHODS: During a 2-year period, all patients were enrolled in this study who had biopsy-proven rectal carcinoma and were referred, as a part of the routine preoperative staging workup, for a CT scan of the abdomen and pelvis and also an MRI of the pelvis. All examinations were reviewed independently by 2 radiologists who were blinded from one another, from the findings of the other modality, and from clinical information. Both observers were dedicated abdominal radiologists who are experienced in reading pelvic CT and MRI. Categorical agreement between MRI and multidetector-row CT for all the evaluated parameters of the tumor position, mesorectal fascia, and lymph nodes, as well as the interobserver agreement between CT and MRI, was determined by the intraclass correlation weighted kappa statistic to measure the data sets consistency. RESULTS: Among the studys 92 patients, the tumor characteristics suggested by multidetector-row CT agreed with those of MRI, with a weighted &kgr; ranging from 0.488 to 0.748 for the first reader and 0.577 to 0.800 for the second reader. Interobserver agreement ranged from 0.506 to 0.746. Agreement regarding mesorectal fascia characteristics differed significantly between multidetector-row CT and MRI, depending on the level of assessment. In the distal rectum, agreement was 0.207 for the first reader and 0.385 for the second reader. In the mid rectum, agreement was 0.420 and 0.527, respectively, and in the proximal rectum agreement was 0.508 and 0.520. Interobserver agreement was 0.737 at the distal level and 0.700 at the mid and proximal levels. Agreement regarding measurement of the distance from the tumor to the mesorectal fascia was 0.425 for the first reader and 0.723 for the second reader, with interobserver agreement of 0.766. Agreement in assessment of the number of lymph nodes ranged from 0.743 to 0.787 for the first reader and 0.754 to 0.840 for the second reader. Interobserver agreement ranged from 0.779 to 0.841. Agreement in assessment of the size of the lymph nodes ranged from 0.540 to 0.830 for the first reader and 0.850 to 0.940 for the second reader. Interobserver agreement ranged from 0.900 to 0.920. Agreement in assessment of the distance from nodes to the mesorectal fascia was 0.320 for the first reader and 0.401 for the second reader, with interobserver agreement of 0.950. CONCLUSION: The results of this study differ from previously published data by demonstrating substantial agreement between readers in multidetector-row CT assessment of the tumor, mesorectal fascia, and lymph nodes. With the exceptions of mesorectal fascia in the distal rectum and the distance from the nodes to mesorectal fascia, other evaluated parameters were assessed with moderate and substantial agreement between multidetector-row CT and MRI. However, our findings suggest that multidetector-row CT does not correlate well enough with MRI findings to replace it in rectal cancer staging.

Hürthle Cell Neoplasms of the Thyroid : Sonographic Appearance and Histologic Characteristics

Objective. The purpose of this study was to determine the sonographic features of Hürthle cell neoplasms (HCNs) of the thyroid. Methods. We retrospectively analyzed the sonographic appearance of 15 histologically proven HCNs in 15 patients aged 16 to 70 years (mean age, 44 years). Sonographic features that were reviewed included the size and echogenicity of the tumors, the presence of cystic areas or calcifications, and detectable blood flow on color Doppler imaging. Correlation of sonographic findings with pathologic results was performed. Results. The tumors ranged from 0.4 to 7 cm in diameter, but most were less than 3 cm in diameter. Four (27%) of the 15 tumors were homogeneously hypoechoic. Two tumors (13%) were predominantly hypoechoic with isoechoic areas to thyroid parenchyma. Two (13%) neoplasms were isoechoic to thyroid parenchyma. Four (27%) tumors were predominantly isoechoic, containing hypoechoic areas, and 3 (20%) tumors were hyperechoic. Three neoplasms contained cystic components. None of the tumors contained calcifications. One tumor was avascular on Doppler examination. One neoplasm showed only peripheral blood flow. Thirteen tumors showed internal vascularity, 7 of them with peripheral blood flow. Twelve HCNs were benign, and 3 were malignant on pathologic examination. Conclusions. Hürthle cell neoplasms show a spectrum of sonographic appearances from predominantly hypoechoic to hyperechoic lesions and from peripheral blood flow with no internal flow to extensively vascularized lesions. Pathologic criteria differentiating benign and malignant HCNs (absence or presence of a capsular breach, vascular or extrathyroidal tissue invasion, nodal involvement, and distant metastasis) are beyond the resolution of sonography and fine‐needle aspiration biopsy and require removal of the entire lesion. This precludes diagnosis and characterization of HCNs by sonography.

Epidermoid Cyst and Teratoma of the Testis Sonographic and Histologic Similarities

The classic sonographic description of an epidermoid cyst is a mass with a target or onion ring appearance of alternating rings of hyperechogenicity and hypoechogenicity. This study presents a pathologic‐sonographic assessment of classic and nonclassic appearances of an epidermoid cyst of the testis and reports the possible similarity between a classic epidermoid cyst and a teratoma on sonography.

MR Arthrography of the Wrist: Controversies and Concepts

Magnetic resonance arthrography (MRA) has become the preferred modality for imaging patients with internal derangement of the wrist. However, several aspects of MRA use need to be clarified before a standardized approach to the imaging of internal derangement of the wrist can be developed. The objective of the study is to evaluate the efficiency of different magnetic resonance (MR) sequences in the detection of lesions of the triangular fibrocartilage complex (TFCC) and scapholunate and lunotriquetral ligaments on direct MRA. Thirty-one consecutive direct magnetic resonance arthrographic examinations of the wrist using a wrist surface coil were performed for the assessment of the TFCC and intrinsic ligaments on a 1.5-T MR imaging system (Signa; 16 channel, Excite, GE Healthcare, Milwaukee, WI, USA). All patients had wrist pain, and in six cases, there was associated clinical carpal instability. The presence, location, and extent of TFCC, scapholunate ligament (SLL), and lunotriquetral ligament (LTL) lesions on T1 fat-saturated, multiplanar gradient recalled (MPGR) and short tau inversion recovery (STIR) images were identified, compared, and analyzed. Forty-one lesions of the TFCC, SLL, and LTL were visualized on contrast-sensitive (T1 fat-saturated) images in 23/31 (74.2%) patients. Twenty-one lesions of the TFCC and intrinsic ligaments were visualized on noncontrast-sensitive (MPGR and STIR) images (15 tears of the TFCC and six tears of the SLL and LTL). All of these lesions were seen on T1 fat-saturated images; 48.8% (20/41) lesions seen on T1 fat-saturated images (eight tears of TFCC and 12 tears of SLL and LTT) were not seen on MPGR and/or STIR images. Superior contrast resolution, joint distention, and the flow of contrast facilitate the diagnosis of lesions of the TFCC and intrinsic ligaments on contrast-sensitive sequences making MRA the preferred modality for imaging internal derangements of the wrist. Little agreement exists regarding the value and location of perforations of the intrinsic ligaments given that both traumatic and degenerative perforations may be symptomatic. Noncommunicating defects of the ulnar attachments of the triangular fibrocartilage (TFC), tears of the dorsal segment of the SLL, and defects at the lunate attachment of the SLL have a higher likelihood of being symptomatic and caused by trauma rather than by degenerative perforation. Although no consensus exists, it would appear that most arthrographies should be started with a radiocarpal injection. Injection into the distal radioulnar joint should be added if no communicational defects are visualized following radiocarpal injection in patients with ulnar-sided wrist pain.

Utility of MRI Before and After Uterine Fibroid Embolization: Why to Do It and What to Look For

The utility of magnetic resonance imaging (MRI) in the selection, procedure planning, and follow-up of patients undergoing arterial embolization for uterine fibroids is reviewed. Advantages of MRI over ultrasound include multiplanar imaging capability, a larger field of view, increased spatial resolution, improved anatomic detail, and the ability to detect other pelvic disorders. MRI can assess fibroid viability by detecting contrast agent enhancement. Magnetic resonance angiography has a useful role in evaluation of pelvic vasculature. Magnetic resonance parameters such as T1 and T2 relaxation times and diffusion-weighted characteristics have an emerging role in predicting outcome before and after embolization. MRI may be used to evaluate technical success and to image potential complications after embolization.

T2 mapping of articular cartilage of glenohumeral joint with routine MRI correlation--initial experience.

The evaluation of articular cartilage currently relies primarily on the identification of morphological alterations of the articular cartilage. Unlike anatomic imaging, T2 mapping is sensitive to changes in the chemical composition and structure of the cartilage. Clinical evaluation of T2 mapping of the glenohumeral joint has not been previously reported. The objectives of this study were to evaluate the feasibility of magnetic resonance T2 mapping of the glenohumeral joint in routine clinical imaging, to assess the normal T2 mapping appearance of the glenohumeral joint, and to compare the findings on T2 maps to conventional MR pulse sequences. Magnetic resonance imaging (MRI) examinations of 27 shoulders were performed in a routine clinical setting. All studies included acquisition of T2 mapping using a dedicated software. The T2 maps were analyzed along with the routine MR exam and correlation of cartilage appearance on T2 map and on conventional MR sequences. T2 imaging maps were obtained successfully in all patients. T2 maps and routine MRI correlated in cases of normal cartilage and prolonged T2 values and cartilage defects. In four cases, increased T2 relaxation times in the cartilage and cartilage defects were more apparent on T2 maps. Acquisition of T2 maps at the time of routine MRI scanning is feasible and not time-consuming.

The association between avulsions of the reflected head of the rectus femoris and labral tears: A retrospective study

Background: The aim of this study was to investigate if an association existed between the reflected head of rectus femoris avulsion injuries and labral tears in pediatric patients referred for magnetic resonance arthrography (MRA) or magnetic resonance imaging (MRI) evaluation. Methods: Electronic medical records of the patients between the ages of 12 and 18 who were treated at the hospitals affiliated by McMaster University between June 2000 and November 2010 with a diagnosis of rectus femoris avulsion injuries were retrospectively identified and analyzed. Patients were included if they had magnetic resonance imaging or MRA images of their hip. Results: Nine patients with avulsion injuries of the rectus femoris muscle were identified. The patient population consisted of 4 females and 5 males (range, 8 to 17 y, mean age 14 y). All injuries occurred during sports activity, which included running and kicking during soccer, skating in hockey, and a squatting exercise. MRA examination of 7 of these patients demonstrated associated labral tears. All patients were initially treated conservatively. Five patients continued to sustain from residual pain in the 9 months after the initial injury. Two of these patients with significant refractory pain were subsequently treated with hip arthroscopy. Intraoperatively, 1 small labral tear and 1 labral avulsion were identified and treated. Conclusions: This study suggests that there may be an association between avulsion of the reflected head of rectus femoris and labral injuries and that there may be an underlying spectrum of traction injuries. Patients with rectus femoris avulsion injuries with persistent symptoms may be at risk for concurrent traumatic labral tears. Level of Evidence: Level 4, retrospective case series.

Is it a fibroid? Are you sure? Sonography with MRI assistance.

Uterine fibroids are common benign lesions. Other common benign masses include renal cysts, renal angiomyolipomas, hepatic cysts, hepatic hemangiomas, thyroid cysts, adrenal incidentalomas, pulmonary granulomas and hamartomas, ovarian cysts, and dermoids. All these conditions, especially in asymptomatic patients, almost never have clinical significance. However, it is important to differentiate them from more sinister or even malignant lesions. In general, when a lesion is described as a fibroid, no further evaluation is performed. So if we say that a lesion is a fibroid, we have to be sure. Endometrial fibroids may mimic endometrial polyps or endometrial cancer. Subserous, especially pedunculated fibroids, may need further evaluation to differentiate them from ovarian pathology, colonic pathology, or even müllerian duct anomalies. Pelvic magnetic resonance imaging may be helpful in these cases.

How to Measure Scapholunate and Cobb’s Angles on MRI and CT

The measurement of angles between anatomical structures is common in radiological and orthopedic practice. Frequently used measurements include scapholunate angle for assessment of wrist instability and Cobb’s angle used for assessment of scoliosis. Measurements of these angles are easily performed on plain X-ray radiographs. However, the situation is more complicated when these measurements are to be performed on cross-sectional (CT or MRI) examinations. On some of the diagnostic workstations, it is not possible to perform angle measurements between the structures if they are not identified on the same image and are located on different images of the same projection or plane. We present a simple solution to measure angles between structures on different images that can be used both in CT and MR.

Do we really need to thank the Beatles for the financing of the development of the computed tomography scanner

Abstract It is commonly believed that the revenues from the selling of the Beatles’ records by Electric and Musical Industries (EMI) allowed the company to develop the computed tomography (CT) scanner. Some went to define this as the Beatles’ gift to medicine. However, significant controversies and discrepancies arise from analysis of this statement, making its correctness doubtful. The details of financing required for the CT development and the part of EMI in financial input have never been publicly announced. This work analyzes the financial contributions to the CT development and investigates if the revenues received from the sales of the Beatles’ records were used for the creation of the CT scanner. Timeline of the development of the EMI CT scanner and the financial inputs of EMI and British Department of Health and Social Security (DHSS) were assessed. Without salary expenses to Godfrey Hounsfield and his team, the development of the CT scanner cost EMI approximately £100,000. The British DHSS’s expenses were £606,000. Hence, the financial contribution of DHSS into the development of the CT scanner was significantly bigger than that of EMI. Accordingly, British tax payers and officials of British DHSS are to be thanked for the CT scanner. The Beatles’ input into the world’s culture is valuable and does not require decoration by nonexistent connection to the development of CT. A positive aspect to this misconception is that it keeps in public memory the name of the company that developed the CT scanner.